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Sample records for antioxidant impacting atmospheric

  1. Atmospheric oxidation and antioxidants

    CERN Document Server

    Meurant, Gerard

    1993-01-01

    Volume I reviews current understanding of autoxidation, largely on the basis of the reactions of oxygen with characterised chemicals. From this flows the modern mechanism of antioxidant actions and their application in stabilisation technology.

  2. Iodide accumulation provides kelp with an inorganic antioxidant impacting atmospheric chemistry

    Science.gov (United States)

    Küpper, Frithjof C.; Carpenter, Lucy J.; McFiggans, Gordon B.; Palmer, Carl J.; Waite, Tim J.; Boneberg, Eva-Maria; Woitsch, Sonja; Weiller, Markus; Abela, Rafael; Grolimund, Daniel; Potin, Philippe; Butler, Alison; Luther, George W.; Kroneck, Peter M. H.; Meyer-Klaucke, Wolfram; Feiters, Martin C.

    2008-01-01

    Brown algae of the Laminariales (kelps) are the strongest accumulators of iodine among living organisms. They represent a major pump in the global biogeochemical cycle of iodine and, in particular, the major source of iodocarbons in the coastal atmosphere. Nevertheless, the chemical state and biological significance of accumulated iodine have remained unknown to this date. Using x-ray absorption spectroscopy, we show that the accumulated form is iodide, which readily scavenges a variety of reactive oxygen species (ROS). We propose here that its biological role is that of an inorganic antioxidant, the first to be described in a living system. Upon oxidative stress, iodide is effluxed. On the thallus surface and in the apoplast, iodide detoxifies both aqueous oxidants and ozone, the latter resulting in the release of high levels of molecular iodine and the consequent formation of hygroscopic iodine oxides leading to particles, which are precursors to cloud condensation nuclei. In a complementary set of experiments using a heterologous system, iodide was found to effectively scavenge ROS in human blood cells. PMID:18458346

  3. The impact of Quercetin like flavonoid antioxidants on Cancer Therapy

    OpenAIRE

    Akan, Zafer

    2015-01-01

    Uncontrolled consumption of medical plants may lead controversial result over the patients who are receiving radiotherapy or chemotherapy for cancer treatment. Especially, flavonoid free radical scavenger including chemical and plants may not be innocent as much as thought. Free radical scavenger antioxidant extracts uses for commonly for two aims; the prevention of cancer and therapy of cancer.In the light of recent developments the impact of antioxidant usage on cancer treatment and prevent...

  4. Impact of Amazonian deforestation on atmospheric chemistry

    OpenAIRE

    Ganzeveld, L.N.; Lelieveld, J.

    2004-01-01

    A single-column chemistry and climate model has been used to study the impact of deforestation in the Amazon Basin on atmospheric chemistry. Over deforested areas, daytime ozone deposition generally decreases strongly except when surface wetness decreases through reduced precipitation, whereas nocturnal soil deposition increases. The isoprene and soil nitric oxide emissions decrease although nitrogen oxide release to the atmosphere increases due to reduced canopy deposition. Deforestation als...

  5. Nitrogen atmosphere and natural antioxidants effect on muesli oxidation during long-time storage

    Directory of Open Access Journals (Sweden)

    Dorota Klensporf-Pawlik

    2009-03-01

    Full Text Available The effects of natural antioxidants from raspberry and black currant seeds and modified atmosphere packaging on muesli oxidative stability measured by monitoring volatile lipid oxidation products were evaluated. The effectiveness toward lipid oxidation was investigated during 10 months storage at ambient temperature. Both ethanolic extracts as well as nitrogen atmosphere influenced lipid oxidation rate in muesli measured by volatile compounds content. The most abundant lipid derived volatile compounds was hexanal. After storage, its concentration changed from 802 µg/kg to 9.8 mg/kg in muesli stored in air atmosphere, whereas in muesli stored in nitrogen atmosphere with raspberry seed extract addition it raised to 3.1 mg/kg. Although, both natural antioxidants rich in phenolic compounds, were effective towards lipid oxidation, the strongest inhibiting effect had modified atmosphere packaging. The addition of ethanolic extracts did not fortify its positive effect. Total concentration of volatile compounds in muesli after 10 months of storage was 19.6 mg/kg when stored in air and 13.7 and 11.8 mg/kg when stored with raspberry and black currant seeds extract addition respectively, while 9.8 mg/kg when stored in nitrogen atmosphere without antioxidants, and 9.7 and 9.9 mg/kg when stored with antioxidants mentioned above.

  6. Impacts of Oxidative Stress and Antioxidants on Semen Functions

    Directory of Open Access Journals (Sweden)

    Amrit Kaur Bansal

    2011-01-01

    Full Text Available Oxidative stress (OS has been considered a major contributory factor to the infertility. Oxidative stress is the result of imbalance between the reactive oxygen species (ROS and antioxidants in the body which can lead to sperm damage, deformity, and eventually male infertility. Although high concentrations of the ROS cause sperm pathology (ATP depletion leading to insufficient axonemal phosphorylation, lipid peroxidation, and loss of motility and viability but, many evidences demonstrate that low and controlled concentrations of these ROS play an important role in sperm physiological processes such as capacitation, acrosome reaction, and signaling processes to ensure fertilization. The supplementation of a cryopreservation extender with antioxidant has been shown to provide a cryoprotective effect on mammalian sperm quality. This paper reviews the impacts of oxidative stress and reactive oxygen species on spermatozoa functions, causes of ROS generation, and antioxidative strategies to reduce OS. In addition, we also highlight the emerging concept of utilizing OS as a tool of contraception.

  7. Impact of biomass burning on the atmosphere

    International Nuclear Information System (INIS)

    Fire has played an important part in biogeochemical cycling throughout most of the history of our planet. Ice core studies have been very beneficial in paleoclimate studies and constraining the budgets of biogeochemical cycles through the past 160,000 years of the Vostok ice core. Although to date there has been no way of determining cause and effect, concentration of greenhouse gases directly correlates with temperature in ice core analyses. Recent ice core studies on Greenland have shown that significant climate change can be very rapid on the order of a decade. This chapter addresses the coupled evolution of our planet's atmospheric composition and biomass burning. Special attention is paid to the chemical and climatic impacts of biomass burning on the atmosphere throughout the last century, specifically looking at the cycles of carbon, nitrogen, and sulfur. Information from ice core measurements may be useful in understanding the history of fire and its historic affect on the composition of the atmosphere and climate

  8. Enhancement of antioxidant effects of naringin after atmospheric pressure dielectric barrier discharge plasma treatment.

    Science.gov (United States)

    Kim, Tae Hoon; Jang, Soo Jeung; Chung, Hyung-Wook; Kim, Hyun-Joo; Yong, Hae In; Choe, Wonho; Jo, Cheorun

    2015-03-15

    Naringin is the natural chief bitter flavonoid found in Citrus species. Herein, bitter naringin was treated with atmospheric pressure plasma to afford two new converted flavonoids, narinplasmins A (2) and B (3), along with the known compound, 2R-naringin. The structures of the two new naringin derivatives were elucidated on the basis of spectroscopic methods. The antioxidant activity of all isolates was evaluated based on 1,1-diphenyl-2-picrylhydrazyl and peroxynitrite (ONOO(-)) scavenging assays. The new flavanone glycoside 2 containing a methoxyalkyl group exhibited significantly improved antioxidant properties in these assays relative to the parent naringin.

  9. Atmospheric impacts of evaporative cooling systems

    International Nuclear Information System (INIS)

    The report summarizes available information on the effects of various power plant cooling systems on the atmosphere. While evaporative cooling systems sharply reduce the biological impacts of thermal discharges in water bodies, they create (at least, for heat-release rates comparable to those of two-unit nuclear generating stations) atmospheric changes. For an isolated site such as required for a nuclear power plant, these changes are rather small and local, and usually environmentally acceptable. However, one cannot say with certainty that these effects will remain small as the number of reactors on a given site increases. There must exist a critical heat load for a specific site which, if exceeded, can create its own weather patterns, and thus create inadvertent weather changes such as rain and snow, severe thunderstorms, and tornadoes. Because proven mathematical models are not available, it is not now possible to forecast precisely the extent and frequency of the atmospheric effects of a particular heat-dissipation system at a particular site. Field research on many aspects of cooling system operation is needed in order to document and quantify the actual atmospheric changes caused by a given cooling system and to provide the data needed to develop and verify mathematical and physical models. The more important topics requiring field study are plume rise, fogging and icing (from certain systems), drift emission and deposition rates, chemical interactions, cloud and precipitation formation and critical heat-release rates

  10. Aircraft induced sulphur impact on the atmosphere

    Science.gov (United States)

    Dessens, O.; Rogers, H. L.; Pyle, J. A.

    2009-12-01

    Sulphur is present in aviation fuel and as consequence SO2 is emitted by aviation in the atmosphere. SO2 is then rapidly oxidised in H2SO4 that can produce sulphuric acid aerosol. The impact of the sulphuric acid aerosol on the atmospheric chemistry has been studied in two different region of the atmosphere: the upper troposphere lower stratosphere (UTLS) and the surface. The first part of the study will focus on the impact of sulphur emissions from aircraft at cruise altitude within the UTLS. The results presented have been obtained with the stratospheric chemistry transport model (CTM) SLIMCAT. For that study a full microphysical module for stratospheric sulphuric aerosol (SAMM) has been included within the CTM. The impact on the ozone concentration in the UTLS is calculated for the present day subsonic fleet emissions. The sulphuric acid aerosol surface density due to aviation reach 1.8μm2/cm3 and the ozone change calculated is -0.22ppbv at the mid-latitudes Northern Hemisphere at 12 km altitude (ozone change due to NOx emissions at the same location: +4.5ppbv). These results are compared to results from other models calculated during the QUANTIFY project. The second part of the study is looking at the impact of the sulphur emitted by aviation below 3kFeet. These calculations have been performed with the tropospheric CTM pTOMCAT. For that purpose a standard tropospheric sulphur cycle as well as a tropospheric microphysic parametrisation of sulphuric acid aerosol have been introduced within pTOMCAT. Two different fuel are used under 3kFeet in the simulations: one normal kerosene and one ultra-low-sulphur (ULS) kerosene. The reduction in sulphuric acid aerosol surface density using the ULS fuel is only reaching -2 to -5% compare to the background surface level (sulphur emissions from other anthropic and biogenic sources are higher than aviation). The impact of the ULS fuel use on the ozone concentration within the planetary boundary layer is relatively weak and

  11. Impact of biomass burning on the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Dignon, J.

    1993-03-01

    Fire has played an important part in biogeochemical cycling throughout most of the history of our planet. Ice core studies have been very beneficial in paleoclimate studies and constraining the budgets of biogeochemical cycles through the past 160,000 years of the Vostok ice core. Although to date there has been no way of determining cause and effect, concentration of greenhouse gases directly correlates with temperature in ice core analyses. Recent ice core studies on Greenland have shown that significant climate change can be very rapid on the order of a decade. This chapter addresses the coupled evolution of our planet`s atmospheric composition and biomass burning. Special attention is paid to the chemical and climatic impacts of biomass burning on the atmosphere throughout the last century, specifically looking at the cycles of carbon, nitrogen, and sulfur. Information from ice core measurements may be useful in understanding the history of fire and its historic affect on the composition of the atmosphere and climate.

  12. ANTIOXIDANT DEPLETION AND OIT VALUES OF HIGH IMPACT PP STRANDS

    Institute of Scientific and Technical Information of China (English)

    Werner W. Muller; Ines Jakob; Chun-shan Li; Renate Tatzky-Gerth

    2009-01-01

    The service life of a polyolefin product depends to large extent on the type and amount of the antioxidants added. During the manufacturing, storage and use of the product the antioxidants are depleted by physical processes and chemical degradation, and this impairs its long-term performance. The initial and in-use oxidation stability is often characterized and monitored by the measurement of the oxidative induction time (OIT), and service life predictions are based on the rate of decrease of the OIT value. To study the correlation between the OIT value and the actual antioxidant concentration, eight random arrays of high-impact polypropylene (PP) strands stabilized using six different antioxidant packages (composed of Irgafos 168, Irganox 1010 and 1330, Chimassorb 944) were immersed in hot water (80℃ and 90℃) and oven aged in air (80℃) for more than two years, and the change of OIT values and antioxidant concentrations was measured. For phosphitic and phenolic stabilizers water immersion is generally a more critical aging condition than oven aging in air, while for the hindered amine stabilizers (HAS) the opposite was observed. As expected, a linear correlation between OIT values and concentrations was found for the "classical" package of phosphitic and phenolic stabilizers. In the case of Irganox 1330, the change of the OIT values during aging was considerably slower than the change of concentration. Even when zero concentration was reached according to the vanishing peak height in the chromatogram, a considerable OIT value was still measurable. This may be due to unidentified degradation products of lrganox 1330 which still act as antioxidants in the long run. Addition of HAS (Chimassorb 944) seems to enhance the initial OIT of stabilized phenolic samples and the long-term effectiveness of the phenolic stabilization under air oven aging conditions. However, the marked long-term effectiveness of the HAS itself and the slow change with time of the

  13. Antioxidants

    Science.gov (United States)

    Antioxidants are man-made or natural substances that may prevent or delay some types of cell damage. Antioxidants are found in many foods, including fruits and ... are also available as dietary supplements. Examples of antioxidants include Beta-carotene Lutein Lycopene Selenium Vitamin A ...

  14. Impact of Polyphenol Antioxidants on Cycling Performance and Cardiovascular Function

    Directory of Open Access Journals (Sweden)

    Joel D. Trinity

    2014-03-01

    Full Text Available This investigation sought to determine if supplementation with polyphenol antioxidant (PA improves exercise performance in the heat (31.5 °C, 55% RH by altering the cardiovascular and thermoregulatory responses to exercise. Twelve endurance trained athletes ingested PA or placebo (PLAC for 7 days. Consecutive days of exercise testing were performed at the end of the supplementation periods. Cardiovascular and thermoregulatory measures were made during exercise. Performance, as measured by a 10 min time trial (TT following 50 min of moderate intensity cycling, was not different between treatments (PLAC: 292 ± 33 W and PA: 279 ± 38 W, p = 0.12. Gross efficiency, blood lactate, maximal neuromuscular power, and ratings of perceived exertion were also not different between treatments. Similarly, performance on the second day of testing, as assessed by time to fatigue at maximal oxygen consumption, was not different between treatments (PLAC; 377 ± 117 s vs. PA; 364 ± 128 s, p = 0.61. Cardiovascular and thermoregulatory responses to exercise were not different between treatments on either day of exercise testing. Polyphenol antioxidant supplementation had no impact on exercise performance and did not alter the cardiovascular or thermoregulatory responses to exercise in the heat.

  15. Atmospheric anthropic impacts tracked by the French atmospheric mobile observatory

    Science.gov (United States)

    Cuesta, J.; Chazette, P.; Flamant, P. H.

    2009-04-01

    A new ATmospheric Mobile ObServatory, so called "ATMOS", has been developed by the LiMAG "Lidar, Meteorology and Geophysics" team of the Institut Pierre Simon Laplace (IPSL) in France, in order to contribute to international field campaigns for studying atmospheric physico-chemistry, air quality and climate (i.e. aerosols, clouds, trace gazes, atmospheric dynamics and energy budget) and the ground-based validation of satellite observations. ATMOS has been deployed in the framework of i) LISAIR, for monitoring air quality in Paris in 2005, ii) AMMA "African Monsoon Multidisciplinary Analysis", in Tamanrasset and in Niamey for observing the aerosols and the atmospheric boundary layer in the Sahara and in the Sahel in 2006, iii) COPS "Convectively and Orographycally driven Precipitation Study" in the Rhin Valley in 2007 and iv) the validation of the spatial mission CALIPSO, launched in April 2006. In the coming years, ATMOS will be deployed i) in the Paris Megacity, in the framework of MEGAPOLI (2009-2010), ii) in southern France (near Marseille) for the Chemistry-Aerosol Mediterranean Experiment CHARMEX (2011-2012) and iii) the validation of ADM-Aeolus in 2010-2011 and Earth-Care in 2012. ATMOS payload is modular, accounting for the different platforms, instruments and measuring techniques. The deployment of ATMOS is an essential contribution to field campaigns, complementing the fixed sites, and a potential alternative of airborne platforms, heavier and more expensive. ATMOS mobile payload comprises both the remote sensing platform MOBILIS ("Moyens mOBIles de téLédetection de l'IPSL") and the in-situ physico-chemical station SAMMO ("Station Aérosols et chiMie MObile"). MOBILIS is an autonomous and high-performance system constituted by a full set of active and passive remote sensing instrumentation (i.e. Lidars and radiometers), whose payload may be adapted for either i) long term fixed monitoring in a maritime container or a shelter, ii) ground-based transect

  16. Antioxidant Activity of Centella asiatica (Linn.) Urban: Impact of Extraction Solvent Polarity

    OpenAIRE

    Asiqur Rahaman; Shahdat Hossain; Taslima Nahar

    2013-01-01

    In vitro antioxidant activity of Centella asiatica (Linn.) and the impact of extraction solvent polarity on the antioxidant potential were investigated in the present study. 100% ethanol, 50% ethanol and water were chosen as extraction solvent due to arithmetic progression of their polarity. Total polyphenol, flavonoid, β-carotene, tannin and vitamin C content of three extracts were estimated while antioxidant potential was assayed by total reducing power assay and 2, 2-diphenyl-1-picrylhydra...

  17. Sex hormones modulate circulating antioxidant enzymes: Impact of estrogen therapy

    Directory of Open Access Journals (Sweden)

    Francesco Bellanti

    2013-01-01

    Conclusions: Menopause is associated with significant change in antioxidant gene expression that in turn affects circulating redox state. Estrogens replacement therapy is able to prevent and counteract such modifications by acting as regulators of key antioxidant gene expression. These findings suggest that antioxidant genes are, almost in part, under the control of sex hormones, and that pathophysiology of the difference in gender disease may depend on the redox biology.

  18. CO2 Impacts on the Martian Atmosphere

    Science.gov (United States)

    Kelley, Michael; Bauer, James; Bodewits, Dennis; Farnham, Tony; Stevenson, Rachel; Yelle, Roger

    2014-09-01

    The dynamically new comet C/2013 A1 (Siding Spring) will pass Mars at the extremely close distance of 140,000 km on 2014 Oct 19. This encounter is unique---a record close approach to a planet with spacecraft that can observe its passage---and currently, all 5 Mars orbiters have plans to observe the comet and/or its effects on the planet. Gas from the comet's coma is expected to collide with the Martian atmosphere, altering the abundances of some species and producing significant heating, inflating the upper atmosphere. We propose DDT observations with Spitzer/IRAC to measure the comet's CO2+CO coma (observing window Oct 30 - Nov 20), to use these measurements to derive the coma's CO2 density at Mars during the closest approach, and to aid the interpretation of any observed effects or changes in the Martian atmosphere.

  19. Genotoxic effect of ethacrynic acid and impact of antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Ward, William M.; Hoffman, Jared D.; Loo, George, E-mail: g_loo@uncg.edu

    2015-07-01

    It is known that ethacrynic acid (EA) decreases the intracellular levels of glutathione. Whether the anticipated oxidative stress affects the structural integrity of DNA is unknown. Therefore, DNA damage was assessed in EA-treated HCT116 cells, and the impact of several antioxidants was also determined. EA caused both concentration-dependent and time-dependent DNA damage that eventually resulted in cell death. Unexpectedly, the DNA damage caused by EA was intensified by either ascorbic acid or trolox. In contrast, EA-induced DNA damage was reduced by N-acetylcysteine and by the iron chelator, deferoxamine. In elucidating the DNA damage, it was determined that EA increased the production of reactive oxygen species, which was inhibited by N-acetylcysteine and deferoxamine but not by ascorbic acid and trolox. Also, EA decreased glutathione levels, which were inhibited by N-acetylcysteine. But, ascorbic acid, trolox, and deferoxamine neither inhibited nor enhanced the capacity of EA to decrease glutathione. Interestingly, the glutathione synthesis inhibitor, buthionine sulfoxime, lowered glutathione to a similar degree as EA, but no noticeable DNA damage was found. Nevertheless, buthionine sulfoxime potentiated the glutathione-lowering effect of EA and intensified the DNA damage caused by EA. Additionally, in examining redox-sensitive stress gene expression, it was found that EA increased HO-1, GADD153, and p21mRNA expression, in association with increased nuclear localization of Nrf-2 and p53 proteins. In contrast to ascorbic acid, trolox, and deferoxamine, N-acetylcysteine suppressed the EA-induced upregulation of GADD153, although not of HO-1. Overall, it is concluded that EA has genotoxic properties that can be amplified by certain antioxidants. - Highlights: • Ethacrynic acid (EA) caused cellular DNA damage. • EA-induced DNA damage was potentiated by ascorbic acid or trolox. • EA increased ROS production, not inhibited by ascorbic acid or trolox. • EA

  20. Giant Impact Induced Atmospheric Blow-Off

    OpenAIRE

    Ahrens, Thomas J.; Shen, Andy H.; Ni, Sidao

    2004-01-01

    Previous calculations indicate that the Earth suffered impacts from objects up to Mars size. Such a giant impact may have produced a temporary ejecta-based ring that accreted to form the Moon. To simulate the surface waves from such events we approximated the cratering source as a buried pressurized sphere. For a 10^27 J impactor we calculated the resulting surface wave using the mode summation method of Sato et al.. For such an impact, the solid Earth free-surface velocity above, and antipod...

  1. Sunglint Impact on Atmospheric Soundings from Hyperspectral Resolution Infrared Radiances

    Institute of Scientific and Technical Information of China (English)

    YAO Zhigang; Jun LI; Jinlong LI

    2012-01-01

    ABSTRACT The mid-wave infrared band (3-5 μm) has been widely used for atmospheric soundings.The sunglint impact on the atmospheric parameter retrieval using this band has been neglected because the reflected radiances in this band are significantly less than those in the visible band.In this study,an investigation of sunglint impact on the atmospheric soundings was conducted with Atmospheric InfraRed Sounder observation data from 1 July to 7 July 2007 over the Atlantic Ocean.The impact of sunglint can lead to a brightness temperature increase of 1.0 K for the surface sensitive sounding channels near 4.58 μm.This contamination can indirectly cause a positive bias of 4 g kg-1 in the water vapor retrieval near the ocean surface,and it can be corrected by simply excluding those contaminated channels.

  2. Impact of biomass burning on the atmosphere. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Dignon, J.

    1994-04-01

    Fire has played an important part in biogeochemical cycling throughout much of the history of our plant. This report addresses the coupled evolution of our planet`s atmospheric composition and biomass burning. Special attention is paid to the chemical and climatic impacts of biomass burning on the atmosphere throughout the last century, specifically looking at the cycles of carbon, nitrogen, and sulfur. Information from ice core measurements may be useful in understanding the history of fire and its historic affect on the composition of the atmosphere and climate.

  3. Impact of aviation upon the atmosphere. Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Carpentier, J. [Comite Avion-Ozone, 75 - Paris (France)

    1997-12-31

    The commercial air traffic, either for business or for tourism will induce a special increase of long haul flights, with cruising altitudes of about 10 to 12 km. These altitudes correspond to the upper troposphere for the low latitudes (tropical zones) and to the lower stratosphere for middle and high latitudes. The prospect of a world air traffic multiplied by a factor 2 within the next fifteen years, with an increasing part of the long-haul flights, raises the problem of the impact of aircraft emissions on the upper troposphere and on the lower stratosphere. The air traffic growth which is forecast for the next two decades as well as for long term will be larger than the GDP growth. But technical progress concerning airframes, engines, navigation systems and improvements of air traffic control and airports will keep the aircraft emissions growth at a rate which will not exceed the GDP growth rate. The aviation`s share of global anthropogenic emissions will remain lower than 3 percent. The regulations related to NO{sub x} emissions from aircraft will reduce the aviation`s share of nitrogen oxides from human sources at a level of 1 percent. (R.P.)

  4. Impact of Atmospheric Forcing on the Ocean Prediction under Typhoon

    Science.gov (United States)

    Ko, D. S.; Wu, C.

    2012-12-01

    The impact of atmospheric forcing on the ocean prediction under Typhoon Fanapi and Typhoon Megi (2010) is investigated applying an ocean nowcast/forecast system (EASNFS) that covers the northwestern Pacific Ocean and the East Asian marginal seas. The model resolution is ~ 8 km at the study area. There are 40 vertical layers with dense upper layers to better resolve upper ocean variations. Ocean model assimilates the altimetry data to produce important subsurface oceanic mesoscale features for the impact study. The atmospheric forcing is provided by an atmospheric model on a triple (54/18/6 km) nested grid that moves with typhoon. The 10-m wind and sea level air pressure are applied to drive ocean model. The wind and air pressure are interpolated onto the ocean model grid and meshed with prediction from NOGAPS (Navy Operational Global Atmospheric Prediction System) to account for the area that the triple nested grid does not cover. The simulation is conducted for the time period from September 1 to October 1, 2010 for the duration of Typhoon Fanapi and from October 1 to November 1, 2010 for Megi. To compare, a parallel simulation driven by NOGAPS forcing alone for the same periods is also conducted. The impact of atmospheric forcing is examined by comparison of ocean model predictions with remote sensing and in-situ data taken during ITOP 2010 Intensive Observation Period.

  5. Free radicals, antioxidants and functional foods: Impact on human health

    OpenAIRE

    Lobo, V.; Patil, A.; A Phatak; N Chandra

    2010-01-01

    In recent years, there has been a great deal of attention toward the field of free radical chemistry. Free radicals reactive oxygen species and reactive nitrogen species are generated by our body by various endogenous systems, exposure to different physiochemical conditions or pathological states. A balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body's ability to regulate them, a condition known as oxidative stress...

  6. The effect of postharvest 1-MCP treatment and storage atmosphere on 'Cripps Pink' apple phenolics and antioxidant activity.

    Science.gov (United States)

    Hoang, Nga T T; Golding, John B; Wilkes, Meredith A

    2011-08-01

    This study investigated the effect of a postharvest 1-methylcyclopropene (1-MCP) treatment, controlled atmosphere and storage time on the total antioxidant activity (TAA) and phenolic compounds in the peel and flesh of 'Cripps Pink' apples (Malus domestica Borkh.). Preclimacteric apples were harvested and treated with 1-MCP then stored in normal atmosphere (NA) or controlled atmosphere (CA) at 0°C for up to 160days. In general, the level of phenolics decreased by 9% in the peel and significantly increased twofold in the flesh during cold storage, regardless of storage atmosphere or 1-MCP treatment. However, treatment with 1-MCP resulted in significantly lower concentrations of chlorogenic acid and procyanidin B2 in apple flesh, and catechin and epicatechin in the peel compared to the control fruits. There was no significant effect of CA on the phenolic compounds during long-term storage, except for quercetin 3-galactoside and quercetin 3-glucoside, which both significantly increased under CA storage. Total antioxidant activity (TAA) is an important nutritional attribute of apples in the human diet. The results showed that TAA in the peel tissue was about eight times higher than that of the flesh, with mean values of 4.75gTE/kgFW and 0.56TE/kgFW, respectively. The TAA in both the peel and flesh tissue increased significantly during storage by 40% and 70%, respectively. The storage atmosphere did not significantly affect TAA in either the peel or flesh, whilst the 1-MCP treatment significantly reduced the TAA in the peel tissue only. These results show the beneficial combined effects of pre-storage 1-MCP treatment and CA on 'Cripps Pink' apple phenolic composition and antioxidant capacity during long term storage.

  7. Atmospheric Nitrogen Inputs to the Ocean and their Impact

    Science.gov (United States)

    Jickells, Tim D.

    2016-04-01

    Atmospheric Nitrogen Inputs to the Ocean and their Impact T Jickells (1), K. Altieri (2), D. Capone (3), E. Buitenhuis (1), R. Duce (4), F. Dentener (5), K. Fennel (6), J. Galloway (7), M. Kanakidou (8), J. LaRoche (9), K. Lee (10), P. Liss (1), J. Middleburg (11), K. Moore (12), S. Nickovic (13), G. Okin (14), A. Oschilies (15), J. Prospero (16), M. Sarin (17), S. Seitzinger (18), J. Scharples (19), P. Suntharalingram (1), M. Uematsu (20), L. Zamora (21) Atmospheric nitrogen inputs to the ocean have been identified as an important source of nitrogen to the oceans which has increased greatly as a result of human activity. The significance of atmospheric inputs for ocean biogeochemistry were evaluated in a seminal paper by Duce et al., 2008 (Science 320, 893-7). In this presentation we will update the Duce et al 2008 study estimating the impact of atmospheric deposition on the oceans. We will summarise the latest model estimates of total atmospheric nitrogen deposition to the ocean, their chemical form (nitrate, ammonium and organic nitrogen) and spatial distribution from the TM4 model. The model estimates are somewhat smaller than the Duce et al estimate, but with similar spatial distributions. We will compare these flux estimates with a new estimate of the impact of fluvial nitrogen inputs on the open ocean (Sharples submitted) which estimates some transfer of fluvial nitrogen to the open ocean, particularly at low latitudes, compared to the complete trapping of fluvial inputs on the continental shelf assumed by Duce et al. We will then estimate the impact of atmospheric deposition on ocean primary productivity and N2O emissions from the oceans using the PlankTOM10 model. The impacts of atmospheric deposition we estimate on ocean productivity here are smaller than those predicted by Duce et al impacts, consistent with the smaller atmospheric deposition estimates. However, the atmospheric input is still larger than the estimated fluvial inputs to the open ocean

  8. Vulnerability assessment of atmospheric environment driven by human impacts.

    Science.gov (United States)

    Zhang, Yang; Shen, Jing; Ding, Feng; Li, Yu; He, Li

    2016-11-15

    Atmospheric environment quality worsening is a substantial threat to public health worldwide, and in many places, air pollution due to the intensification of the human activity is increasing dramatically. However, no studies have been investigated the integration of vulnerability assessment and atmospheric environment driven by human impacts. The objective of this study was to identify and prioritize the undesirable environmental changes as an early warning system for environment managers and decision makers in term of human, atmospheric environment, and social economic elements. We conduct a vulnerability assessment method of atmospheric environment associated with human impact, this method integrates spatial context of Geographic Information System (GIS) tool, multi-criteria decision analysis (MCDA) method, ordered weighted averaging (OWA) operators under the Exposure-Sensitivity- Adaptive Capacity (ESA) framework. Decision makers can find out relevant vulnerability assessment results with different vulnerable attitudes. In the Beijing-Tianjin-Hebei (BTH) region, China, we further applied this developed method and proved it to be reliable and consistent with the China Environmental Status Bulletin. Results indicate that the vulnerability of atmospheric environment in the BTH region is not optimistic, and environment managers should do more about air pollution. Thus, the most appropriate strategic decision and development program of city or state can be picked out assisting by the vulnerable results. PMID:27424115

  9. Vulnerability assessment of atmospheric environment driven by human impacts.

    Science.gov (United States)

    Zhang, Yang; Shen, Jing; Ding, Feng; Li, Yu; He, Li

    2016-11-15

    Atmospheric environment quality worsening is a substantial threat to public health worldwide, and in many places, air pollution due to the intensification of the human activity is increasing dramatically. However, no studies have been investigated the integration of vulnerability assessment and atmospheric environment driven by human impacts. The objective of this study was to identify and prioritize the undesirable environmental changes as an early warning system for environment managers and decision makers in term of human, atmospheric environment, and social economic elements. We conduct a vulnerability assessment method of atmospheric environment associated with human impact, this method integrates spatial context of Geographic Information System (GIS) tool, multi-criteria decision analysis (MCDA) method, ordered weighted averaging (OWA) operators under the Exposure-Sensitivity- Adaptive Capacity (ESA) framework. Decision makers can find out relevant vulnerability assessment results with different vulnerable attitudes. In the Beijing-Tianjin-Hebei (BTH) region, China, we further applied this developed method and proved it to be reliable and consistent with the China Environmental Status Bulletin. Results indicate that the vulnerability of atmospheric environment in the BTH region is not optimistic, and environment managers should do more about air pollution. Thus, the most appropriate strategic decision and development program of city or state can be picked out assisting by the vulnerable results.

  10. The potential impact of hydrogen energy use on the atmosphere

    Science.gov (United States)

    van Ruijven, B. J.; Lamarque, J. F.; van Vuuren, D. P.; Kram, T.; Eerens, H.

    2009-04-01

    Energy models show very different trajectories for future energy systems (partly as function of future climate policy). One possible option is a transition towards a hydrogen-based energy system. The potential impact of such hydrogen economy on atmospheric emissions is highly uncertain. On the one hand, application of hydrogen in clean fuel cells reduces emissions of local air pollutants, like SOx and NOx. On the other hand, emissions of hydrogen from system leakages are expected to change the atmospheric concentrations and behaviour (see also Price et al., 2007; Sanderson et al., 2003; Schultz et al., 2003; Tromp et al., 2003). The uncertainty arises from several sources: the expected use of hydrogen, the intensity of leakages and emissions, and the atmospheric chemical behaviour of hydrogen. Existing studies to the potential impacts of a hydrogen economy on the atmosphere mostly use hydrogen emission scenarios that are based on simple assumptions. This research combines two different modelling efforts to explore the range of impacts of hydrogen on atmospheric chemistry. First, the potential role of hydrogen in the global energy system and the related emissions of hydrogen and other air pollutants are derived from the global energy system simulation model TIMER (van Vuuren, 2007). A set of dedicated scenarios on hydrogen technology development explores the most pessimistic and optimistic cases for hydrogen deployment (van Ruijven et al., 2008; van Ruijven et al., 2007). These scenarios are combined with different assumptions on hydrogen emission factors. Second, the emissions from the TIMER model are linked to the NCAR atmospheric model (Lamarque et al., 2005; Lamarque et al., 2008), in order to determine the impacts on atmospheric chemistry. By combining an energy system model and an atmospheric model, we are able to consistently explore the boundaries of both hydrogen use, emissions and impacts on atmospheric chemistry. References: Lamarque, J.-F., Kiehl, J. T

  11. Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants

    Institute of Scientific and Technical Information of China (English)

    Sugreev; Verma; Kousik; Kesh; Nilanjan; Ganguly; Sayantan; Jana; Snehasikta; Swarnakar

    2014-01-01

    The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases(MMPs). Degradation of extracellular matrix(ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metallopro-teinase(TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK(reversion including cysteinerich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2,-9 and-14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species(ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is

  12. Potential Atmospheric Impact Generated by Space Launches Worldwide

    Science.gov (United States)

    Brady, B. B.; Desain, J. D.; Curtiss, T. J.

    2010-12-01

    This paper evaluates the exhaust products generated from launch vehicles worldwide. Information on atmospheric deposition of carbon dioxide, water vapor, nitrogen dioxide, sulfates, inorganic chlorine and alumina particulates due to launch vehicles is presented. The potential for environmental impact from ozone destruction and global climate change due to space launches from worldwide sources is discussed. The exhaust from launch vehicles contains many components that have the potential to effect atmospheric concentrations of greenhouse gases. These greenhouse gases absorb and emit radiation within the thermal infrared range. The loss or gain of greenhouse gases has the net effect of changing the total global radiative balance. Launch vehicles are different than many other anthropogenic sources of these exhaust components (primarily the burning of fossil fuels), because vehicles deposit these exhaust components at all levels of the Earth’s atmosphere rather than just the lower troposphere.

  13. Simulating the Atmospheric Impact of Criegee Intermediates: Implementation of new understanding in atmospheric chemical mechanisms

    Science.gov (United States)

    Bloss, William; Newland, Mike; Rickard, Andrew; Vereecken, Luc; Evans, Mathew; Munoz, Amalia; Rodenas, Mila

    2016-04-01

    Unsaturated hydrocarbons - alkenes - account for about 90% of global VOC. Stabilized Criegee Intermediates (SCI) are thought to be formed in the atmosphere mainly from reactions of unsaturated hydrocarbons with ozone. SCI have been shown in laboratory and chamber experiments to rapidly oxidise SO2 and NO2, providing a potentially important gas phase oxidation route for these species in the atmosphere. They have also been implicated in the formation of aerosol and organic acids. However, the importance of SCI reactions with traces gases is critically dependent on the relative ratio of the rate constants for the reactions of the SCI with these and other trace gases, with H2O, and for unimolecular decomposition, which vary between SCIs, and between geometric isomers. The selection of reactions and rate constants is critically important in determining the calculated impact of SCI processes upon atmospheric composition and chemistry. Since the recent resurgence in interest in this chemistry, a number of model studies have been performed, with SCI mechanisms of varying comprehensiveness and accuracy, as the understanding of the community has evolved from new laboratory, theoretical and chamber studies, and field observations. Here we present an assessment of the dependence of modelled SCI abundance, behaviour and impacts upon the Criegee mechanism adopted, in the context of (a) the accepted status quo prior to the laboratory and field studies of Welz et al. and Mauldin et al., (b) changes to the SCI mechanism reflecting new kinetics for key bimolecular reactions, e.g. with SO2 and NO2; (c) emerging understanding of the interactions of SCI with water vapour and their unimolecular decomposition and (d) reactions with other atmospheric trace gases. The modelled SCI behaviour is compared with the results from recent chamber studies, and the resulting calculated SCI abundance and impacts evaluated for urban and forested atmospheric boundary layer scenarios.

  14. The trajectory and atmospheric impact of asteroid 2014 AA

    Science.gov (United States)

    Farnocchia, Davide; Chesley, Steven R.; Brown, Peter G.; Chodas, Paul W.

    2016-08-01

    Near-Earth asteroid 2014 AA entered the Earth's atmosphere on 2014 January 2, only 21 h after being discovered by the Catalina Sky Survey. In this paper we compute the trajectory of 2014 AA by combining the available optical astrometry, seven ground-based observations over 69 min, and the International Monitoring System detection of the atmospheric impact infrasonic airwaves in a least-squares orbit estimation filter. The combination of these two sources of observations results in a tremendous improvement in the orbit uncertainties. The impact time is 3:05 UT with a 1σ uncertainty of 6 min, while the impact location corresponds to a west longitude of 44.2° and a latitude of 13.1° with a 1σ uncertainty of 140 km. The minimum impact energy estimated from the infrasound data and the impact velocity result in an estimated minimum mass of 22.6 t. By propagating the trajectory of 2014 AA backwards we find that the only window for finding precovery observations is for the three days before its discovery.

  15. The atmospheric impact trajectory of asteroid 2014 AA

    CERN Document Server

    Farnocchia, D; Brown, P G; Chodas, P W

    2016-01-01

    Near-Earth asteroid 2014 AA entered the Earth's atmosphere on 2014 January 2, only 21 hours after being discovered by the Catalina Sky Survey. In this paper we compute the trajectory of 2014 AA by combining the available optical astrometry, seven ground-based observations over 69 minutes, and the International Monitoring system detection of the atmospheric impact infrasonic airwaves in a least-squares orbit estimation filter. The combination of these two sources of observations results in a tremendous improvement in the orbit uncertainties. The impact time is 3:05 UT with a 1-sigma uncertainty of 6 min, while the impact location corresponds to a west longitude of 44.7 deg and a latitude of 13.1 deg with a 1-sigma uncertainty of 140 km. The minimum impact energy estimated from the infrasound data and the impact velocity result in an estimated minimum mass of 22.6 t. By propagating the trajectory of 2014 AA backwards we find that the only window for finding precovery observations is for the three days before it...

  16. Transport impacts on atmosphere and climate: Land transport

    Science.gov (United States)

    Uherek, Elmar; Halenka, Tomas; Borken-Kleefeld, Jens; Balkanski, Yves; Berntsen, Terje; Borrego, Carlos; Gauss, Michael; Hoor, Peter; Juda-Rezler, Katarzyna; Lelieveld, Jos; Melas, Dimitrios; Rypdal, Kristin; Schmid, Stephan

    2010-12-01

    Emissions from land transport, and from road transport in particular, have significant impacts on the atmosphere and on climate change. This assessment gives an overview of past, present and future emissions from land transport, of their impacts on the atmospheric composition and air quality, on human health and climate change and on options for mitigation. In the past vehicle exhaust emission control has successfully reduced emissions of nitrogen oxides, carbon monoxide, volatile organic compounds and particulate matter. This contributed to improved air quality and reduced health impacts in industrialised countries. In developing countries however, pollutant emissions have been growing strongly, adversely affecting many populations. In addition, ozone and particulate matter change the radiative balance and hence contribute to global warming on shorter time scales. Latest knowledge on the magnitude of land transport's impact on global warming is reviewed here. In the future, road transport's emissions of these pollutants are expected to stagnate and then decrease globally. This will then help to improve the air quality notably in developing countries. On the contrary, emissions of carbon dioxide and of halocarbons from mobile air conditioners have been globally increasing and are further expected to grow. Consequently, road transport's impact on climate is gaining in importance. The expected efficiency improvements of vehicles and the introduction of biofuels will not be sufficient to offset the expected strong growth in both, passenger and freight transportation. Technical measures could offer a significant reduction potential, but strong interventions would be needed as markets do not initiate the necessary changes. Further reductions would need a resolute expansion of low-carbon fuels, a tripling of vehicle fuel efficiency and a stagnation in absolute transport volumes. Land transport will remain a key sector in climate change mitigation during the next decades.

  17. Analysis Of The 2009 July Impact Debris In Jupiter'S Atmosphere

    Science.gov (United States)

    Sanchez-Lavega, Agustin; Hueso, R.; Legarreta, J.; Pérez-Hoyos, S.; García-Melendo, E.; Gómez, J. M.; Rojas, J. F.; Orton, G. S.; Wesley, A.; IOPW International Outer Planet Watch Team

    2009-09-01

    We report the analysis of images obtained by the contributors to the International Outer Planet Watch (IOPW) of the debris left in the atmosphere of Jupiter by the object that impacted the planet between 18 and 19 July 2009. The discovery images by Anthony Wesley in July 19.625 and the first two days of its tracking, shows a dark debris spot (continuum wavelength) located at planetocentric latitude -55.1 deg and 304.5 deg System III longitude. The imaging survey indicates that the spot was not present in July 18.375, so the impact occurred during a window between both dates. The main spot had a size of about 4,500 km and to its Northwest a thin debris halo of similar size was initially observed. Methane band images at a wavelength of 890 nm shows the spot to be bright indicating that the debris aerosols are highly placed in the atmosphere relative to surrounding clouds. At the central latitude of the impact, the Jovian flow has nearly zero speed but anticyclonic vorticity bounded by jets at -51.5 deg (directed westward with velocity -10 m/s) and at -57.5 deg (directed eastward with velocity 25 m/s). The morphology in the continuum and the spot brightness in the methane band strongly suggest that the feature was caused by a cometary or asteroidal impact, similar in behaviour to the SL9 impacts of 1994. This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07. RH acknowledges a "Ramón y Cajal” contract from MEC.

  18. Solar wind interaction with Venus and impact on its atmosphere

    Science.gov (United States)

    Barabash, S.; Futaana, Y.; Wieser, G. S.; Luhmann, J.

    2014-04-01

    We present a review of the solar wind interaction with Venus and how the interaction affects the Venusian atmosphere. The Venus Express observations for more than 8 years (2005-present) and quantitatively new simulation codes substantially advanced physical understanding of the plasma processes in the near-Venus space since the Pioneer Venus Orbiter (PVO) mission (1978-1992). The near-Venus space can be divided into several plasma domains: the magnetotail with the plasmasheet, induced magnetosphere, and magnetosheath. The bow shock separates the undisturbed solar wind from the Venus-affected environment. We review the shapes and positions of the boundaries enveloping the main domains and discuss how they are formed by the current systems and pressure balance. In particular, we discuss the morphology and dynamics of the near-Venus magnetotail that was not accessible by PVO. Using the unique Venus Express measurements we discuss the ion acceleration processes and their links to the ionosphere. The focus is given to the Venus' atmosphere erosion associated with the solar wind interaction, both through the energy (ion acceleration) and momentum (atmospheric sputtering) transfer. We review the measurements of the escape rates, their variability with the upstream solar wind conditions and the solar cycle. We emphasize the measurements duirng extreme solar wind conditions as an analogue with nominal conditions for the young Sun. The modeling efforts in this area are also reviewed as they provide a quantitatively approach to understand the impact of the solar wind interaction on the atmospheric evolution. Finally, we compare Venus with other planets of the terrestrial planet group, the Earth and Mars. The Earth, a twin planet of the similar size, is magnetized. Mars, an unmagnetized planet like Venus, possesses by far weaker gravitation to hold its atmospheric gasses. This comparative magnetosphere approach based on the natural solar system laboratory of experiments gives

  19. Effects of 1-Methylcyclopropene and Modified Atmosphere Packaging on the Antioxidant Capacity in Pepper “Kulai” during Low-Temperature Storage

    OpenAIRE

    Chung Keat Tan; Zainon Mohd Ali; Ismanizan Ismail; Zamri Zainal

    2012-01-01

    The objective of the present study was to simultaneously evaluate the effect of a postharvest treatment on the pepper's antioxidant content and its ability to retain its economical value during the postharvest period. The fruits were pretreated by modified atmosphere packaging (MAP) with or without treatment with 1-methylcyclopropene (1-MCP) before cold storage at 10°C. Changes in the levels of non-enzymatic antioxidants, including the total phenolic, ascorbic acid levels and the total glutat...

  20. Impact of aircraft emissions on the atmospheric chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dameris, M.; Sausen, R.; Grewe, V.; Koehler, I.; Ponater, M. [Deutsche Forschungs- und Versuchsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Steil, B. [Max-Planck-Inst. fuer Meteorologie, Hamburg (Germany); Bruehl, Ch. [Max-Planck-Inst. fuer Chemie (Otto-Hahn-Institut), Mainz (Germany)

    1997-12-31

    A hierarchy of models of different complexity has been applied to estimate the impact of aircraft NO{sub x} emissions on atmospheric chemistry. The global circulation model ECHAM3 has been coupled with two types of chemistry modules. The first of these describes only a simplified (linear) NO{sub x} and HNO{sub 3} chemistry while the second one is a comprehensive chemistry module (CHEM), describing tropospheric and stratospheric chemistry including photochemical reactions and heterogeneous reactions on sulphate aerosols and PSCs. The module CHEM has been coupled either off-line or with feedback via the ozone concentration. First results of multilayer integrations (over decades) are discussed. (author) 27 refs.

  1. Effects of antioxidants on the fate and impact of spilled vegetable oils in aquatic environments

    Energy Technology Data Exchange (ETDEWEB)

    Salam, D.A.; Suidan, M.T. [University of Cincinnati (United States)], email: salamda@email.uc.edu; Venosa, A.D. [U.S. Environmental Protection Agency (United States)

    2011-07-01

    Adding antioxidants to vegetable oils prevents lipid oxidation. Antioxidants always influence oil biodegradability and their toxicity patterns in impacted water bodies. This study used glyceryl trilinoleate as a model system to investigate the impact of butylated-hydroxytoluene (BHT) concentration on the biodegradability of vegetable oils and induced toxicity. As is known, glyceryl trilinoleate is the most susceptible triglyceride with regard to auto-oxidation. Biodegradation experiments on glyceryl trilinoleate were run by means of respirometric experiments. In this study, various concentrations of BHT ranging from 0 to 200 ppm (no BHT added, 50, 100, 200) were tested and the completely mixed conditions in 250 mL microcosms were simulated. There were three replicate samples and three abiotic blanks per BHT level. Through observing the competition between polymerization and biodegradation, it was found out that toxicity did not exist in the liquid phase after 19 weeks of incubation with the exception of the abiotic blanks with no BHT added.

  2. Ozone in the atmosphere. Basic principles, natural and human impacts

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Peter [Technical Univ. Munich (Germany). Immission Research; Dameris, Martin [German Aerospace Center (DLR), Oberpfaffenhofen-Wessling (Germany). Inst. of Atmospheric Physics

    2014-09-01

    Comprehensive coverage of ozone both in the upper and the lower atmosphere. Essential overview of atmospheric ozone research written by two experienced and acknowledged experts. Numerous qualified references to the scientific literature. Peter Fabian and Martin Dameris provide a concise yet comprehensive overview of established scientific knowledge about ozone in the atmosphere. They present both ozone changes and trends in the stratosphere, as well as the effects of overabundance in the troposphere including the phenomenon of photosmog. Aspects such as photochemistry, atmospheric dynamics and global ozone distribution as well as various techniques for ozone measurement are treated. The authors outline the various causes for ozone depletion, the effects of ozone pollution and the relation to climate change. The book provides a handy reference guide for researchers active in atmospheric ozone research and a useful introduction for advanced students specializing in this field. Non-specialists interested in this field will also profit from reading the book. Peter Fabian can look back on a life-long active career in ozone research, having first gained international recognition for his measurements of the global distribution of halogenated hydrocarbons. He also pioneered photosmog investigations in the metropolitan areas of Munich, Berlin, Athens and Santiago de Chile, and his KROFEX facility provided controlled ozone fumigation of adult tree canopies for biologists to investigate the effects of ozone increases on forests. Besides having published a broad range of scientific articles, he has also been the author or editor of numerous books. From 2002 to 2005 he served the European Geosciences Union (EGU) as their first and Founding President. Martin Dameris is a prominent atmospheric modeler whose interests include the impacts of all kinds of natural and man-made disturbances on the atmospheric system. His scientific work focuses on the connections between ozone and

  3. Ozone in the atmosphere. Basic principles, natural and human impacts

    International Nuclear Information System (INIS)

    Comprehensive coverage of ozone both in the upper and the lower atmosphere. Essential overview of atmospheric ozone research written by two experienced and acknowledged experts. Numerous qualified references to the scientific literature. Peter Fabian and Martin Dameris provide a concise yet comprehensive overview of established scientific knowledge about ozone in the atmosphere. They present both ozone changes and trends in the stratosphere, as well as the effects of overabundance in the troposphere including the phenomenon of photosmog. Aspects such as photochemistry, atmospheric dynamics and global ozone distribution as well as various techniques for ozone measurement are treated. The authors outline the various causes for ozone depletion, the effects of ozone pollution and the relation to climate change. The book provides a handy reference guide for researchers active in atmospheric ozone research and a useful introduction for advanced students specializing in this field. Non-specialists interested in this field will also profit from reading the book. Peter Fabian can look back on a life-long active career in ozone research, having first gained international recognition for his measurements of the global distribution of halogenated hydrocarbons. He also pioneered photosmog investigations in the metropolitan areas of Munich, Berlin, Athens and Santiago de Chile, and his KROFEX facility provided controlled ozone fumigation of adult tree canopies for biologists to investigate the effects of ozone increases on forests. Besides having published a broad range of scientific articles, he has also been the author or editor of numerous books. From 2002 to 2005 he served the European Geosciences Union (EGU) as their first and Founding President. Martin Dameris is a prominent atmospheric modeler whose interests include the impacts of all kinds of natural and man-made disturbances on the atmospheric system. His scientific work focuses on the connections between ozone and

  4. Impact of phytic acid on nutrient bioaccessibility and antioxidant properties of dehusked rice.

    Science.gov (United States)

    Lee, H H; Loh, S P; Bong, C F J; Sarbini, S R; Yiu, P H

    2015-12-01

    Whole grains consumption promotes health benefits, but demonstrates controversial impacts from phytic acid in meeting requirements of good health. Therefore, this study was aimed to determine the nutrient bioaccessibility and antioxidant properties of rice cultivars named "Adan" or "Bario" and deduce the nutritional impact of phytic acid. Majority of the dehusked rice in the collection showed an acceptable level of in-vitro starch digestibility and in-vitro protein digestibility, but were poor in antioxidant properties and bioaccessibility of minerals (Ca, Fe and Zn). The drawbacks identified in the rice cultivars were due to relatively high phytic acid content (2420.6 ± 94.6 mg/100 g) and low phenolic content (152.39 ± 18.84 μg GAE/g). The relationship between phytic acid content and mineral bioaccessibility was strongest in calcium (r = 0.60), followed by iron (r = 0.40) and zinc (r = 0.27). Phytic acid content did not significantly correlate with in-vitro starch digestibility and in-vitro protein digestibility but showed a weak relationship with antioxidant properties. These suggest that phytic acid could significantly impair the mineral bioaccessibility of dehusked rice, and also act as an important antioxidant in non-pigmented rice. Bario rice cultivars offered dehusked rice with wide range of in-vitro digestibility of starch and protein, and also pigmented rice as a good source of antioxidants. However, there is a need to reduce phytic acid content in dehusked rice for improved mineral bioaccessibility among Bario rice cultivars. PMID:26604353

  5. The impact of oceanic heat transport on the atmospheric circulation

    CERN Document Server

    Knietzsch, Marc-Andre; Lunkeit, Frank

    2014-01-01

    A general circulation model of intermediate complexity with an idealized earthlike aquaplanet setup is used to study the impact of changes in the oceanic heat transport on the global atmospheric circulation. Focus is put on the Lorenz energy cycle and the atmospheric mean meridional circulation. The latter is analysed by means of the Kuo-Eliassen equation. The atmospheric heat transport compensates the imposed oceanic heat transport changes to a large extent in conjunction with significant modification of the general circulation. Up to a maximum about 3PW, an increase of the oceanic heat transport leads to an increase of the global mean near surface temperature and a decrease of its equator-to-pole gradient. For larger transports, the gradient is reduced further but the global mean remains approximately constant. This is linked to a cooling and a reversal of the temperature gradient in the tropics. A larger oceanic heat transport leads to a reduction of all reservoirs and conversions of the Lorenz energy cycl...

  6. Meteor bodies entering the Martian atmosphere: possible impact consequences

    Science.gov (United States)

    Kuznetsova, Daria; Gritsevich, Maria

    The investigation of meteorite production on Mars has attracted considerable attention during the recent years. The possible meteorite showers are identified e.g. [1], and the estimates of meteorite fluxes on Mars are found e.g. [2,3]. In this study, we develop the theory describing a meteoroid entry into an atmosphere of a planet and apply our results to the Martian atmosphere. We introduce two key dimensionless parameters, which are based on physical parameterization and have unique values for every single meteoroid case. This allows us to derive the condition for the meteorite fall identification in a simple analytical form, which can be directly implemented for analysis and classification of the possible impact consequences. To describe the motion we use the classical equations of the model of meteor body deceleration [4,5]. The analytical dimensionless solution for the mass-velocity dependence and the height-velocity dependence can be expressed using two main parameters: (i) the ballistic coefficient alpha, which shows the ratio between the mass of the atmospheric column along the trajectory and the body's pre-entry mass, and (ii) the mass loss parameter beta, which is proportional to the ratio between the initial kinetic energy of the body and energy which is required to insure total mass loss of the body due to ablation and fragmentation [6-8]. To determine the possible consequences of impact for any given meteoroid, we use the meteorite-fall condition: the terminal mass of the meteoroid should exceed or be equal to a certain chosen value. This condition can be written using the parameters alpha and beta, so the impact consequences are described by the position of the case-under-investigation point relatively to the boundary curve in the (alpha,beta) space. Following a number of studies [9-11] we analyze the hypothesis that describes the possible evolution of Martian atmospheric density until present. Based on the properties of the meteorites recently found

  7. The Impact of Clouds and Hazes in Substellar Atmospheres

    Science.gov (United States)

    Morley, Caroline; Fortney, Jonathan J.; Marley, Mark S.

    2016-01-01

    The formation of clouds significantly alters the spectra of cool substellar atmospheres from terrestrial planets to brown dwarfs. In cool planets like Earth and Jupiter, volatile species like water and ammonia condense to form ice clouds. In hot planets and brown dwarfs, iron and silicates instead condense, forming dusty clouds. Irradiated methane-rich planets may have substantial hydrocarbon hazes. During my thesis, I have studied the impact of clouds and hazes in a variety of substellar objects. First, I present results for cool brown dwarfs including clouds previously neglected in model atmospheres. Model spectra that include sulfide and salt clouds can match the spectra of T dwarf atmospheres; water ice clouds will alter the spectra of the newest and coldest brown dwarfs, the Y dwarfs. These sulfide/salt and ice clouds potentially drive spectroscopic variability in these cool objects, and this variability should be distinguishable from variability caused by hot spots.Next, I present results for small, cool exoplanets between the size of Earth and Neptune, so-called super Earths. They likely have sulfide and salt clouds and also have photochemical hazes caused by stellar irradiation. Vast resources have been dedicated to characterizing the handful of super Earths accessible to current telescopes, yet of the planets smaller than Neptune studied to date, all have radii in the near-infrared consistent with being constant in wavelength, likely showing that these small planets are consistently enshrouded in thick hazes and clouds. Very thick, lofted clouds of salts or sulfides in high metallicity (1000× solar) atmospheres create featureless transmission spectra in the near-infrared. Photochemical hazes with a range of particle sizes also create featureless transmission spectra at lower metallicities. I show that despite these challenges, there are promising avenues for understanding this class of small planets: by observing the thermal emission and reflectivity of

  8. Processes Impacting Atmosphere-Surface Exchanges at Arctic Terrestrial Sites

    Science.gov (United States)

    Persson, Ola; Grachev, Andrey; Konopleva, Elena; Cox, Chris; Stone, Robert; Crepinsek, Sara; Shupe, Matthew; Uttal, Taneil

    2015-04-01

    Surface energy fluxes are key to the annual cycle of near-surface and soil temperature and biologic activity in the Arctic. While these energy fluxes are undoubtedly changing to produce the changes observed in the Arctic ecosystem over the last few decades, measurements have generally not been available to quantify what processes are regulating these fluxes and what is determining the characteristics of these annual cycles. The U.S. National Oceanic and Atmospheric Administration has established, or contributed to the establishment of, several terrestrial "supersites" around the perimeter of the Arctic Ocean at which detailed measurements of atmospheric structure, surface fluxes, and soil thermal properties are being made. These sites include Barrow, Alaska; Eureka and Alert, Canada; and Tiksi, Russia. Atmospheric structure measurements vary, but include radiosoundings at all sites and remote sensing of clouds at two sites. Additionally, fluxes of sensible heat and momentum are made at all of the sites, while fluxes of moisture and CO2 are made at two of the sites. Soil temperatures are also measured in the upper 120 cm at all sites, which is deep enough to define the soil active layer. The sites have been operating between 3 years (Tiksi) and 24 years (Barrow). While all sites are located north of 71° N, the summer vegetation range from lush tundra grasses to rocky soils with little vegetation. This presentation will illustrate some of the atmospheric processes that are key for determining the annual energy and temperature cycles at these sites, and some of the key characteristics that lead to differences in, for instance, the length of the summer soil active layer between the sites. Atmospheric features and processes such as cloud characteristics, snowfall, downslope wind events, and sea-breezes have impacts on the annual energy cycle. The presence of a "zero curtain" period, when autumn surface temperature remains approximately constant at the freezing point

  9. Modelling the impact of aircraft emissions on atmospheric composition

    Science.gov (United States)

    Wasiuk, D. K.; Lowenberg, M. H.; Shallcross, D. E.

    2012-12-01

    Emissions of the trace gases CO2, CO, H2O, HC, NOx, and SOx that have the potential to perturb large scale atmospheric composition are accumulating in the atmosphere at an unprecedented rate as the demand for air traffic continues to grow. We investigate the global and regional effects of aircraft emissions on the atmosphere and climate using mathematical modelling, sensitivity simulations, and perturbation simulations and present historical and spatial distribution evolution of the global and regional number of departures, fuel burn and emissions. A comprehensive aircraft movement database spanning years 2005 - 2012, covering 225 countries and over 223 million departures on approximately 41000 unique routes serves as a basis for our investigation. We combine air traffic data with output from an aircraft performance model (fuel burn and emissions) including 80 distinct aircraft types, representing 216 of all the aircraft flown in the world in 2005 - 2012. This accounts for fuel burn and emissions for 99.5% of the total number of departures during that time. Simulations are being performed using a state of the art 3D Lagrangian global chemical transport model (CTM) CRI-STOCHEM for simulation of tropospheric chemistry. The model is applied with the CRI (Common Representative Intermediates) chemistry scheme with 220 chemical species, and 609 reactions. This allows us to study in detail the chemical cycles driven by NOx, governing the rate of formation of O3 which controls the production of OH and indirectly determines the lifetime of other greenhouse gases. We also investigate the impact of the Eyjafjallajökull eruption on the European air traffic and present a model response to the perturbation of NOx emissions that followed.

  10. The impact of oceanic heat transport on the atmospheric circulation

    Directory of Open Access Journals (Sweden)

    M.-A. Knietzsch

    2014-11-01

    Full Text Available A general circulation model of intermediate complexity with an idealized earthlike aquaplanet setup is used to study the impact of changes in the oceanic heat transport on the global atmospheric circulation. Focus is put on the Lorenz energy cycle and the atmospheric mean meridional circulation. The latter is analysed by means of the Kuo–Eliassen equation. The atmospheric heat transport compensates the imposed oceanic heat transport changes to a large extent in conjunction with significant modification of the general circulation. Up to a maximum about 3 PW, an increase of the oceanic heat transport leads to an increase of the global mean near-surface temperature and a decrease of its equator-to-pole gradient. For larger transports, the gradient is reduced further but the global mean remains approximately constant. This is linked to a cooling and a reversal of the temperature gradient in the tropics. A larger oceanic heat transport leads to a reduction of all reservoirs and conversions of the Lorenz energy cycle but of different relative magnitude for the individual components. The available potential energy of the zonal mean flow and its conversion to eddy available potential energy are affected most. Both the Hadley and Ferrel cell show a decline for increasing oceanic heat transport, with the Hadley cell being more sensitive. Both cells exhibit a poleward shift of their maxima, and the Hadley cell broadens for larger oceanic transports. The partitioning, by means of the Kuo–Eliassen equation, reveals that zonal mean diabatic heating and friction are the most important sources for changes of the Hadley cell, while the behaviour of the Ferrell cell is mostly controlled by friction.

  11. European Commission research on aircraft impacts in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Amanatidis, G.T.; Angeletti, G. [European Commission (CEC), Brussels (Belgium)

    1997-12-31

    Aircraft engines release in the troposphere and lower stratosphere a number of chemical compounds (NO{sub x}, CO{sub 2}, CO, H{sub 2}O, hydrocarbons, sulphur, soot, etc.) which could potentially affect the ozone layer and the climate through chemical, dynamical and radiative changes. The global amount of gases and particles emitted by current subsonic and projected supersonic aircraft fleets can be estimated, but significant uncertainties remain about the fate of these emissions in the atmosphere. The European efforts concerning these potential atmospheric impacts of aircraft emissions are conducted by the Environment and Climate Research Programme of the European Commission (EC) as well as by national programmes of the Member States of the European Union (EU). The European research activities in this field, are described, divided for practical reasons in two periods. The first includes activities supported under the 3. Framework Programme for R and D activities which covered the period from 1992 up to 1996, while the second period has started in early 1996 and is supported under the 4. Framework Programme. (R.P.) 6 refs.

  12. Impact of increased anthropogenic atmospheric nitrogen deposition on ocean biogeochemistry

    Science.gov (United States)

    Yang, Simon; Gruber, Nicolas

    2015-04-01

    In the last century, the strong increase in anthropogenic emissions and agricultural activities brought about a tripling in atmospheric nitrogen deposition (AND) rates to oceans. There is growing evidence for a strong fingerprint of increased AND on aquatic systems. Increases in excess N over P (N*) have been attributed to the growing anthropogenically sourced N-deposition in the North western Pacific (Kim et al. 2011) and the North Pacific (Kim et al. 2014). In this study, we use the ocean component of the global earth system model CESM and forced it with transient atmospheric nitrogen deposition from 1850 to 2000 (Lamarque et al. 2013) to study the impact of increased N-deposition on ocean biogeochemistry. We simulate detectable signals in N* in the northern hemisphere as well as a complex pattern of increases and decreases in ocean productivity, with the former causing an expansion of oxygen minimum zones and an increase in water column denitrification. The increase in AND also reduces the ecological niches for N2-fixers, causing a substantial decrease in global ocean N-fixation. Despite this increase in N-loss by denitrification and decrease in N-gain by N-fixation, the increase in AND has put the global marine N-budget severely out of balance ( 10 TgN.yr-1). Finally, we extend our simulation to 2100 using the RCP 8.5 emission scenario to find that these changes will probably grow in the future.

  13. Effect of controlled atmosphere storage on pericarp browning, bioactive compounds and antioxidant enzymes of litchi fruits.

    Science.gov (United States)

    Ali, Sajid; Khan, Ahmad Sattar; Malik, Aman Ullah; Shahid, Muhammad

    2016-09-01

    'Gola' litchi fruits were stored under ten different CA-combinations at 5±1°C to investigate its effects on pericarp browning, biochemical quality and antioxidative activities. Control fruit turned completely brown after 28days of storage and were excluded from the study. Fruit-stored under CA7-combination (1% O2+5% CO2) showed reduced weight loss, pericarp browning, membrane leakage and malondialdehyde contents. Soluble solid contents, titratable acidity and ascorbic acid contents were higher in CA7-stored fruit. Activities of catalase and superoxide dismutase enzymes, levels of total anthocyanins, DPPH radical-scavenging-activity and phenolic contents were significantly higher in CA7-stored litchi fruit. In contrast, activities of polyphenol oxidase and peroxidase enzymes were substantially lower in fruit kept under CA7-combination. Fruit subjected to CA7-conditions also maintained higher organoleptic quality. In conclusion, 1% O2+5% CO2 CA-conditions delayed pericarp browning, maintained antioxidative activities and biochemical characteristics along with better organoleptic quality of litchi fruit for 35days. PMID:27041293

  14. Effect of modified atmosphere packaging (MAP) with low and superatmospheric oxygen on the quality and antioxidant enzyme system of golden needle mushrooms (Flammulina velutipes) during postharvest storage

    NARCIS (Netherlands)

    Wang, Cheng T.; Wang, Chang T.; Cao, Y.P.; Nout, M.J.R.; Sun, B.G.; Liu, L.

    2011-01-01

    To quantify the effect of oxygen concentrations on the quality and antioxidant enzyme system of stored golden needle mushroom, modified atmosphere packaging (MAP) with low and initial superatmospheric oxygen was applied during mushroom storage, and physiological changes associated with postharvest d

  15. The impact of match-play tennis in a hot environment on indirect markers of oxidative stress and antioxidant status

    Science.gov (United States)

    Knez, Wade L; Périard, JP

    2014-01-01

    Objectives The purpose of this study was to determine the impact of changes in oxidative stress and antioxidant status in response to playing tennis in HOT (∼36°C and 35% relative humidity (RH)) and COOL (∼22°C and 70% RH) conditions. Methods 10 male tennis players undertook two matches for an effective playing time (ie, ball in play) of 20 min, corresponding to ∼122 and ∼107 min of total play in HOT and COOL conditions, respectively. Core body temperature, body mass and indirect markers of oxidative stress (diacrons reactive oxygen metabolic test) and antioxidant status (biological antioxidant potential test) were assessed immediately prematch, midmatch and postmatch, and 24 and 48 h into recovery. Results Regardless of the condition, oxidative stress remained similar throughout play and into recovery. Likewise, match-play tennis in the COOL had no impact on antioxidant status. However, antioxidants status increased significantly in the HOT compared with COOL environment (ptennis in the heat does not exacerbate the development of oxidative stress, but significantly increases antioxidant status. These data suggest that the heat stress observed in the HOT environment may provide a necessary signal for the upregulation of antioxidant defence, dampening cellular damage. PMID:24668382

  16. PRESERVING THE QUALITY AND PROLONGATION THE SHELF-LIFE OF BEEF PACKED UNDER VACUUM OR MODIFIED ATMOSPHERE USING TERNARY ANTIOXIDANT BLEND

    Directory of Open Access Journals (Sweden)

    Alexander Stoyanov Staykov

    2016-06-01

    Full Text Available Keeping the quality and prolongation the shelf-life of stored at 0  0.5ºC packed under vacuum or modified (80%О2/20%СО2 atmosphere beef m. semimembranosus sprayed with 0.02% solution, containing 10 g.l-1 dihydroquercetin from Siberian larch (Larix sibirica Ledeb, 5 g.l-1 rosemary (Rosmarinus officinalis extract and 1 g.l-1 L-ascorbic acid was studied. The experiments were carried out with five samples: control - air packaged; vacuum packaged; vacuum packaged and treated with 0.02% ternary antioxidant blend; packaged under modified atmosphere (80%O2/20%CO2; and packaged under rich in oxygen modified atmosphere, after spaying with 0.02% ternary antioxidant blend. Samples were stored 28 days (to 32 d post mortem at 0  0.5ºC. The pre-treatment of beef with ternary antioxidant blend preserve the sensory scores and colour properties of beef, and inhibited total microbial growth, and development of Brochothrix termosphacta and pathogens to the end of storage (28 d at 0  0.5ºC, was found. The pre-treatment of beef with ternary antioxidant blend was not main factors which can affect the pH and free amino nitrogen changes in fresh beef. The pre-treatment of beef with 0.02% ternary antioxidant blend may be successfully used for preserving the quality and prolonging the shelf-life of beef m. semimembranosus packed under modified (80%О2/20%СО2 atmosphere. The shelf-life can extend with 75% compared to air packed meat, and with 7 days against only vacuum- or modified atmosphere packed beef.

  17. Solar activity impact on the Earth's upper atmosphere

    Science.gov (United States)

    Kutiev, Ivan; Tsagouri, Ioanna; Perrone, Loredana; Pancheva, Dora; Mukhtarov, Plamen; Mikhailov, Andrei; Lastovicka, Jan; Jakowski, Norbert; Buresova, Dalia; Blanch, Estefania; Andonov, Borislav; Altadill, David; Magdaleno, Sergio; Parisi, Mario; Miquel Torta, Joan

    2013-02-01

    The paper describes results of the studies devoted to the solar activity impact on the Earth's upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomagnetic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV) radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data.

  18. Solar activity impact on the Earth’s upper atmosphere

    Directory of Open Access Journals (Sweden)

    Parisi Mario

    2013-02-01

    Full Text Available The paper describes results of the studies devoted to the solar activity impact on the Earth’s upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomagnetic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data.

  19. The impact of space electric field research on atmospheric studies

    Science.gov (United States)

    Mozer, F. S.

    1974-01-01

    Space measurements of electric fields have provided instrumentation for measuring atmospheric parameters and a better basis for understanding the electrical coupling between the magnetosphere and the atmosphere. Applications of an incoherent scatter radar (developed for ionospheric electric field research) to the measurement of atmospheric winds and turbulence and of Langmuir double probes (also developed for space research) for measurement of atmospheric electric fields are described. The increased knowledge of magnetospheric electric fields has focused attention on the electrical coupling between the magnetosphere and the atmosphere with conclusions that should considerably modify previous physical concepts in both domains.

  20. Atmospheric pressure photoionization mass spectrometry as a tool for the investigation of the hydrolysis reaction mechanisms of phosphite antioxidants

    Science.gov (United States)

    Papanastasiou, M.; McMahon, A. W.; Allen, N. S.; Johnson, B. W.; Keck-Antoine, K.; Santos, L.; Neumann, M. G.

    2008-08-01

    The hydrolysis reaction mechanism of phosphite antioxidants is investigated by liquid chromatography-mass spectrometry (LC/MS). The phosphites were chosen because they differed in chemical structure and phosphorus content. Dopant assisted-atmospheric pressure photoionization (DA-APPI) is chosen as the ion source for the ionization of the compounds. In our previous work, DA-APPI was shown to offer an attractive alternative to atmospheric pressure chemical ionization (APCI) since it provided background-ion free mass spectra and higher sensitivity [M. Papanastasiou, et al., Polymer Degradation and Stability 91 (11) (2006) 2675-2682]. In positive ion mode, the molecules are generally detected in their protonated form. In negative ion mode, the phosphites are unstable and only fragment ions are observed; these however, are characteristic of each phosphite and may be used for the identification of the analytes in complex mixtures. The analytes under investigation are exposed to accelerated humid ageing conditions and their hydrolytic pathway and stability is investigated. Different substituents around the phosphorus atom are shown to have a significant effect on the stability of the phosphites, with phenol substituents producing very hydrolytically stable structures. Alkanox P24 and PEP-36 follow a similar hydrolytic pathway via the scission of the first and then the second POphenol bonds, eventually leading to the formation of phenol, phosphorous acid and pentaerythritol as end products. HP-10 exhibits a rather different structure and the products detected suggest scission of either the POhydrocarbon or one of the POphenol bonds. A phenomenon similar to that of autocatalysis is observed for all phosphites and is attributed to the formation of dialkyl phosphites as intermediate products.

  1. Impact of Melatonin Enrichment during Germination of Legumes on Bioactive Compounds and Antioxidant Activity.

    Science.gov (United States)

    Aguilera, Yolanda; Herrera, Teresa; Liébana, Rosa; Rebollo-Hernanz, Miguel; Sanchez-Puelles, Carlos; Martín-Cabrejas, María A

    2015-09-16

    This study assesses the impact of melatonin enriched watering on the germination of lentils (Lens culinaris L.) and kidney beans (Phaseolus vulgaris L.). The melatonin levels in lentil and bean sprouts measured by HPLC-MS/MS were more important than those found in other legumes and sprouts, being higher in lentil (1090 ng/g) than in kidney bean (529 ng/g) sprouts. This alternative germination promoted a significant increase of the development of radicles in comparison with the traditional germination. The decreases in the phenolic load were less accentuated than previously observed (lentil sprouts displayed 394 mg gallic acid equivalents (GAE)/100 g of dry weight (DW)), probably due to the protective effect of melatonin. The antioxidant capacity (oxygen radical absorbing capacity assay) increased in these sprouts, reaching 85 and 56 μmol of Trolox equivalents/g DW in lentils and beans, respectively. Hence, the melatonin-enriched foods exhibited potent free radical scavenger and antioxidant functions that may be used as a nutritional strategy to alleviate and prevent chronic and age-related diseases. PMID:26307852

  2. IMPACT OF HEAVY METALS ON ANTIOXIDANT ACTIVITY IN DIFFERENT TISSUE OF MILK FISH Chanos chanos.

    Directory of Open Access Journals (Sweden)

    Sivakumar Rajeshkumar,

    2013-02-01

    Full Text Available The impact of heavy metal accumulation on antioxidant activity in Chanos chanos, (Milk fish was studied in two different locations polluted sites (Kaattuppalli Island and less polluted sites (Kovalam estuary. Accumulation of heavy metals in the gills, liver and muscles were observed Zn >Fe >Cu >Pb >Mn >Cd >Ni. The results reveal that highest concentration of metals in muscle, gills and liver were observed in Kaattuppalli Island when compared to Kovalam estuary. The antioxidant activity showed significant increased in lipid peroxidase (LPO, superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GPx, glutathione-S-tranferese (GST and reduced glutathione (GSH in different tissues of Chanos chanos collected Kaattuppalli Island. Among the studied enzymes, total glutathione peroxidase, catalase and glutathione Stransferase appeared to be the most responsive biomarkers of oxidative stress biomarkers and membrane disruption as the sensitive parameters of environmental pollutant contamination and their importance in biomonitoring of aquatic ecosystems. This is also the first such attempt reported at the tissue level from South India stressing the importance of biomarkers in biomonitoring programmes using fish muscle, gills and liver as the model system.

  3. Effects of 1-Methylcyclopropene and Modified Atmosphere Packaging on the Antioxidant Capacity in Pepper “Kulai” during Low-Temperature Storage

    Directory of Open Access Journals (Sweden)

    Chung Keat Tan

    2012-01-01

    Full Text Available The objective of the present study was to simultaneously evaluate the effect of a postharvest treatment on the pepper's antioxidant content and its ability to retain its economical value during the postharvest period. The fruits were pretreated by modified atmosphere packaging (MAP with or without treatment with 1-methylcyclopropene (1-MCP before cold storage at 10°C. Changes in the levels of non-enzymatic antioxidants, including the total phenolic, ascorbic acid levels and the total glutathione level, as well as enzymatic antioxidants, including ascorbate peroxidase (APX, glutathione reductase (GR, and catalase (CAT, were determined. Both treatments successfully extended the shelf life of the fruit for up to 25 days, and a high level of antioxidant capacity was maintained throughout the storage period. However, 1-MCP treatment maintained the high antioxidant capacity for a longer period of time. The 1-MCP-treated peppers maintained high levels of phenolic content, a high reduced glutathione (GSH/oxidised glutathione (GSSG ratio, decreased levels of ascorbic acid and CAT activity, and increased levels of APX and GR compared with the peppers that were not treated with 1-MCP. The overall results suggested that a combination of 1-MCP and MAP was the most effective treatment for extending shelf life while retaining the nutritional benefits.

  4. Impacts of Passive Smoking on Learning and Memory Ability of Mouse Offsprings and Intervention by Antioxidants

    Institute of Scientific and Technical Information of China (English)

    JIE YANG; ZHU-GE XI; JUN-WEN LI; LI-NA JIANG; ZHEN-LI YUAN; YU-FEI ZHENG; LU WANG; MIN JI; ZHI-QIANG SHEN; XIN-WEI WANG; QIANG MA

    2008-01-01

    Objective To determine the impact of passive smoking and the protective effect of antioxidants such as vitamin E and quercetin on learning and memory ability of mouse offsprings. Methods A passive smoking model of pregnant mice wasestablished.Learning and memory ability was evaluated by the water maze test and long term potentiation (LTP).Nitric oxide (No),content, nitric oxide synthase(NOS),acetylcholinesteras(Ache)activity in brain,vitamin E concentration,and reactive oxygen species(ROS)in seruln were determined.The latency period(the time during which the mice swim from the starting position to the ending position)and errors(the number of mice entering the blind end)in control and antioxidant intervention groups were compared with those in the smoke exposure group after6 days.Results The latency period as well as errors in the air,control diet,tobacco smoke(TS),and vitaminE diet groups were decreased significantlyas compared with the TS and control diet groups (P<0.05).LTP was restrained in the TS and control diet groups.LTP in all the antioxidant diet groups was significantly increased compared with the TS and control diet groups.In addition,NOS and acetylcholinesteras(Ache)activitiy was significantly higher in the TS and control diet groups than in the air and control diet group.NO content was not significantly different amongthedifferent groups,and significantly lower in the TS and vitamin E diet groups than in the TS group,control diet group,quercetin diet group,and mixture diet group(P<0.05).Vitamin E concentration and ROS activity in serum were correlated with the outcome of water maze and LTP.Conclusion Passive smoking reduces LTP formation by disturbing the hippocampus function of mice.by decreasing NOS and Ache activity and increasing NO content.Antioxidants (especially vitamin E)partially improve the learning and memory ability of offsprings whose mothers are exposed to tobacco smoke during pregnancy.

  5. Swell impact on wind stress and atmospheric mixing in a regional coupled atmosphere-wave model

    DEFF Research Database (Denmark)

    Wu, Lichuan; Rutgersson, Anna; Sahlée, Erik;

    2016-01-01

    -wave-coupled regional climate model, separately and combined. The swell influence on atmospheric mixing is introduced into the atmospheric mixing length formula by adding a swell-induced contribution to the mixing. The swell influence on the wind stress under wind-following swell, moderate-range wind, and near...... reduces the near-surface wind speed. Introducing the wave influence roughness length has a larger influence than does adding the swell influence on mixing. Compared with measurements, adding the swell influence on both atmospheric mixing and wind stress gives the best model performance for the wind speed...... when developing climate models....

  6. Atmospheric Impacts of Marcellus Shale Gas Activities in Southwestern Pennsylvania

    Science.gov (United States)

    Presto, A. A.; Lipsky, E. M.; Saleh, R.; Donahue, N. M.; Robinson, A. L.

    2012-12-01

    Pittsburgh and the surrounding regions of southwestern Pennsylvania are subject to intensive natural gas exploration, drilling, and extraction associated with the Marcellus Shale formation. Gas extraction from the shale formation uses techniques of horizontal drilling followed by hydraulic fracturing. There are significant concerns about air pollutant emissions from the development and production of shale gas, especially methane emissions. We have deployed a mobile monitoring unit to investigate the atmospheric impacts of Marcellus Shale gas activities. The mobile sampling platform is a van with an on-board generator, a high-resolution GPS unit, cameras, and instrumentation for measuring methane, criteria gases (SO2, NOx, CO, O3), PM size distributions (scanning mobility particle sizer), black carbon mass (multi-angle absorption photometer), particle-bound polycyclic aromatic hydrocarbons, volatile organic compounds (gas chromatograph with flame ionization detection), and meteorological data. A major advantage of the mobile sampling unit over traditional, stationary monitors is that it allows us to rapidly visit a variety of sites. Sampling at multiple sites allows us to characterize the spatial variability of pollutant concentrations related to Marcellus activity, particularly methane. Data collected from the mobile sampling unit are combined with GIS techniques and dispersion models to map pollutants related to Marcellus Shale operations. The Marcellus Shale gas activities are a major and variable source of methane. The background methane concentration in Pittsburgh is 2.1 +/- 0.2 ppm. However, two southwestern Pennsylvania counties with the highest density of Marcellus Shale wells, Washington and Greene Counties, have many areas of elevated methane concentration. Approximately 11% of the sampled sites in Washington County and nearly 50% of the sampled sites in Greene County have elevated (>2.3 ppm) methane concentrations, compared to 1.5% of sites with elevated

  7. Impact of middle-atmospheric composition changes on greenhouse cooling in the upper atmosphere

    Science.gov (United States)

    Akmaev, R. A.; Fomichev, V. I.; Zhu, X.

    2006-12-01

    The greenhouse effect, commonly associated with lower-atmospheric warming, manifests as cooling in the middle and upper atmosphere. Carbon dioxide is the main cooler and its continuing rise has been demonstrated to result in dramatic temperature reductions, particularly in the thermosphere. In a hydrostatic atmosphere, the cooling is associated with a density decrease at a given height. The stratospheric ozone depletion documented in satellite observations since 1979 and a steady increase of water vapor are also expected to introduce a net cooling in the middle atmosphere primarily via a reduced solar heating and increased emissions in the infrared, respectively. These effects are simulated with the global spectral mesosphere/lower thermosphere model (SMLTM) extending approximately from the tropopause to over 200 km. Climatological distributions of the radiatively active gases are prescribed in the model, which makes it suitable for studies with imposed realistic trends in CO2, O3, and H2O approximately corresponding to the period 1980 2000. Although confined to the stratosphere, the ozone depletion has a profound cooling effect on mesospheric temperatures, which is comparable to or exceeding that of the CO2 forcing. The water vapor cooling appears to play a secondary but non-negligible role, especially in the overall density reduction in the lower thermosphere. The additional hydrostatic contraction of the colder middle atmosphere is predicted to result in a local maximum of the density decline near 110 km of up to -6.5% per decade over the twenty-year period.

  8. Spectroscopic Observation of Chemical Interaction Between Impact-induced Vapor Clouds and the Ambient Atmosphere

    Science.gov (United States)

    Sugita, S.; Heineck, J. T.; Schultz, P. H.

    2000-01-01

    Chemical reactions within impact-induced vapor clouds were observed in laboratory experiments using a spectroscopic method. The results indicate that projectile-derived carbon-rich vapor reacts intensively with atmospheric nitrogen.

  9. Pathways, Impacts, and Policies on Severe Aerosol Injections into the Atmosphere: 2011 Severe Atmospheric Aerosols Events Conference

    KAUST Repository

    Weil, Martin

    2012-09-01

    The 2011 severe atmospheric events conference, held on August 11-12, 2011, Hamburg, Germany, discussed climatic and environmental changes as a result of various kinds of huge injections of aerosols into the atmosphere and the possible consequences for the world population. Various sessions of the conference dealt with different aspects of large aerosol injections and severe atmospheric aerosol events along the geologic time scale. A presentation about radiative heating of aerosols as a self-lifting mechanism in the Australian forest fires discussed the question of how the impact of tropical volcanic eruptions depends on the eruption season. H.-F. Graf showed that cloud-resolving plume models are more suitable to predict the volcanic plume height and dispersion than one-dimensional models. G. Stenchikov pointed out that the absorbing smoke plumes in the upper troposphere can be partially mixed into the lower stratosphere because of the solar heating and lofting effect.

  10. Raman microspectroscopy for probing the impact of a dietary antioxidant on human breast cancer cells.

    Science.gov (United States)

    Medeiros, P S C; Batista de Carvalho, A L M; Ruano, C; Otero, J C; Marques, M P M

    2016-06-15

    Breast cancer is the second most common type of cancer worldwide and the most frequent among women, being the fifth cause of death from neoplastic disease. Since this is an oxidative-stress related neoplasia, it is largely preventable. A dietary isoflavone abundant in soybean - daidzein - is currently being investigated owing to its chemopreventive and/or chemotherapeutic properties towards the human MDA-MB-231 (metastatic, estrogen-unresponsive) and MCF-7 (estrogen-responsive) breast cancer cell lines. Biological assays for evaluation of antitumour and anti-invasive activities were combined with state-of-the-art vibrational microspectroscopy techniques. At 50 and 100 μM concentrations and 48 h incubation time, daidzein was found to induce a marked decrease in cell viability (ca. 50%) for MDA-MB-231 and MCF-7 cells (respectively ca. 50% and 42%) and 40% inhibition of cell migration. MicroRaman analysis of fixed cells upon exposure to this isoflavone unveiled its metabolic impact on both cell lines. Multivariate data analysis (unsupervised PCA) led to a clear discrimination between the control and DAID-exposed cells, with distinctive effects on their biochemical profile, particularly regarding DNA, lipids and protein components, in a cell-dependent way. This is the first reported study on the impact of dietary antioxidants on cancer cells by microRaman techniques. PMID:27227510

  11. Impacts of 3 years of elevated atmospheric CO

    NARCIS (Netherlands)

    Drigo, B.; Kowalchuk, G.A.; Knapp, B.A.; Pijl, A.S.; Boschker, H.T.S.; van Veen, J.A.

    2013-01-01

    Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term i

  12. Atmospheric ions, boreal forests and impacts on climate

    Science.gov (United States)

    Manninen, H. E.; Nieminen, T.; Franchin, A.; Järvinen, E.; Kontkanen, J.; Hirsikko, A.; Hõrrak, U.; Mirme, A.; Tammet, H.; Kerminen, V.-M.; Petäjä, T.; Kulmala, M.

    2012-04-01

    Aerosol particles play an important role in the Earth's atmosphere and in the climate system: They scatter and absorb solar radiation, facilitate chemical processes, and serve as seeds for cloud formation. The aerosol particles have direct cooling and warming effects on climate (IPCC, 2007). Secondary new particle formation (NPF) is a globally important source of aerosol particles (Kulmala and Kerminen, 2008). Currently, the mechanisms of particle formation and the vapors participating in this process are, however, not truly understood. Several formation and growth mechanisms have been proposed for the very first steps of the process: homogeneous, heterogeneous, ion-induced and kinetic nucleation and activation type cluster growth. Small ions are part of the atmospheric aerosol spectrum, and in atmospheric sciences study of ion-aerosol interactions is essential. Small ions are small molecular clusters carrying a net electric charge. They are produced by ionisation of molecules in the air. Typically the small ion concentrations vary in the range of 100-2000 cm-3 in both polarities (Hirsikko et al., 2011). Ion-induced NPF is limited by the ion production rate, which typically is around 10 ion pairs cm-3s-1 in the boundary layer over the ground. The ion production rate has strong spatial and temporal dependence. The ionisation mechanisms change with altitude: radon and gamma radiation from the ground and galactic cosmic rays dominate close to the Earth's surface, while higher in the free troposphere cosmic rays become the main driving factor. In order to fully explain atmospheric NPF and subsequent growth, we need to measure directly the very initial steps of the formation processes. Air ion spectrometers measure the mobility distributions of charged aerosol particles in the mobility diameter range of 0.8-42 nm (Mirme et al., 2007; Tammet et al., 2011). Neutral cluster and air ion spectrometers measure additionally the mobility distribution of neutral particles larger

  13. Impact of aerosols and atmospheric particles on plant leaf proteins

    Science.gov (United States)

    Yan, Xing; Shi, Wen Z.; Zhao, Wen J.; Luo, Na N.

    2014-05-01

    Aerosols and atmospheric particles can diffuse and absorb solar radiation, and directly affect plant photosynthesis and related protein expression. In this study, for the first time, we performed an extensive investigation of the effects of aerosols and atmospheric particles on plant leaf proteins by combining Geographic Information System and proteomic approaches. Data on particles with diameters of 0.1-1.0 μm (PM1) from different locations across the city of Beijing and the aerosol optical depth (AOD) over the past 6 years (2007-2012) were collected. In order to make the study more reliable, we segregated the influence of soil pollution by measuring the heavy metal content. On the basis of AOD and PM1, two regions corresponding to strong and weak diffuse solar radiations were selected for analyzing the changes in the expression of plant proteins. Our results demonstrated that in areas with strong diffuse solar radiations, plant ribulose bisphosphate carboxylase was expressed at higher levels, but oxygen evolved in enhancer protein and light-harvesting complex II protein were expressed at lower levels. The expression of ATP synthase subunit beta and chlorophyll a-b binding protein were similar in both regions. By analyzing the changes in the expression of these leaf proteins and their functions, we conclude that aerosols and atmospheric particles stimulate plant photosynthesis facilitated by diffuse solar radiations.

  14. Geoinformation modeling system for analysis of atmosphere pollution impact on vegetable biosystems using space images

    Science.gov (United States)

    Polichtchouk, Yuri; Ryukhko, Viatcheslav; Tokareva, Olga; Alexeeva, Mary

    2002-02-01

    Geoinformation modeling system structure for assessment of the environmental impact of atmospheric pollution on forest- swamp ecosystems of West Siberia is considered. Complex approach to the assessment of man-caused impact based on the combination of sanitary-hygienic and landscape-geochemical approaches is reported. Methodical problems of analysis of atmosphere pollution impact on vegetable biosystems using geoinformation systems and remote sensing data are developed. Landscape structure of oil production territories in southern part of West Siberia are determined on base of processing of space images from spaceborn Resource-O. Particularities of atmosphere pollution zones modeling caused by gas burning in torches in territories of oil fields are considered. For instance, a pollution zones were revealed modeling of contaminants dispersal in atmosphere by standard model. Polluted landscapes areas are calculated depending on oil production volume. It is shown calculated data is well approximated by polynomial models.

  15. Acute effects of a large bolide impact simulated by a global atmospheric circulation model

    Science.gov (United States)

    Thompson, Starley L.; Crutzen, P. J.

    1988-01-01

    The goal is to use a global three-dimensional atmospheric circulation model developed for studies of atmospheric effects of nuclear war to examine the time evolution of atmospheric effects from a large bolide impact. The model allows for dust and NOx injection, atmospheric transport by winds, removal by precipitation, radiative transfer effects, stratospheric ozone chemistry, and nitric acid formation and deposition on a simulated Earth having realistic geography. Researchers assume a modest 2 km-diameter impactor of the type that could have formed the 32 km-diameter impact structure found near Manson, Iowa and dated at roughly 66 Ma. Such an impact would have created on the order of 5 x 10 to the 10th power metric tons of atmospheric dust (about 0.01 g cm(-2) if spread globally) and 1 x 10 to the 37th power molecules of NO, or two orders of magnitude more stratospheric NO than might be produced in a large nuclear war. Researchers ignore potential injections of CO2 and wildfire smoke, and assume the direct heating of the atmosphere by impact ejecta on a regional scale is not large compared to absorption of solar energy by dust. Researchers assume an impact site at 45 N in the interior of present day North America.

  16. Impact of Wind Farms on the Marine Atmospheric Boundary Layer

    DEFF Research Database (Denmark)

    Volker, Patrick J.H.; Hall, Alex; Capps, Scott B.;

    The presented work is part of a study sponsored by the California Institute of Energy and Environment, in which the impact of the aimed increasing contribution of clean alternative energy sources in the next 30 years will be investigated. Due to the huge wind energy potential along the Californian...... coast, we will focus on the environmental impacts of large offshore wind farms which become feasible, since offshore turbine technology has matured significantly in the last decade....

  17. The environmental radiological atmospheric impact modelling system (ERAIMS) at ANSTO, Lucas Heights

    International Nuclear Information System (INIS)

    Decision-makers managing the emergency response to an actual or potential release of airborne radionuclides from the Lucas Heights Science and Technology Centre (LHSTC) require real-time estimates of the trajectory and dispersion of any released radionuclides. Complex terrain surrounding the LHSTC has an impact on the downwind trajectory and atmospheric dispersion of released radionuclides. Under certain atmospheric conditions, the released cloud could be transported into the valley without direct impact on the nearest population. This entrapment in the steep sided, narrow valley, might mean that the cloud could remain more concentrated and cause impacts on more distant receptor populations down the valley. Alternatively, the cloud could disperse directly across the valley to the nearest residential population without any significant entrainment into, or impact, on the valley. The Environmental Radiological Atmospheric Impact Modelling System (ERAIMS) is a realtime response model which has been developed for the LHSTC. It estimates downwind impacts based on a pre-set source term, prevailing meteorological conditions which are measured every 15 minutes, receptor characteristics and exposure pathways. This paper describes the total system, from collection and calibration of meteorological data, to the running of the models in the ANSTO emergency response facility and display of data for controllers of any emergency. The current assessment of different atmospheric dispersion models available for use in this facility will also be discussed in terms of atmospheric tracer studies conducted in the region and International Best Practice. Copyright (2000) Australasian Radiation Protection Society Inc

  18. The impact of extrusion on the content of polyphenols and antioxidant activity of rye grains (Secale cereale L.

    Directory of Open Access Journals (Sweden)

    Dorota Gumul

    2010-09-01

    Full Text Available Background. Polyphenols which are included in a group of food antioxidants have a beneficial impact on human organism, as they prevent the occurrence of life style diseases, including cardiovascular diseases and cancer. Cereals are the main source of polyphenols in a human diet, and especially rye is characterized by high level of these compounds. Many technological processes applied in food production cause a decrease of polyphenols in rye and reduce their antioxidative activity. The aim of the study was to estimate quantitative changes of polyphenols in rye grains subjected to extrusion, under varying process conditions and establish the antioxidant activity of the obtained rye extrudates. Material and methods. The materials were extrudates prepared from grains of three rye cultivars, namely Amilo, Rostockie and Agrikolo. Extrusion was performed in a single-screw laboratory extruder Brabender 20 DN. Contents of phenolic acids and apigenin in analysed samples was checked by HPLC. Antioxidant activity was measured by FRAP and EPR methods. Results. All rye extrudates contained ferulic acid levels (53-104 mg/100 g d.m. approximately 112-316% higher as compared to raw material (25 mg/100 g d.m.. The highest antioxidant activity (using of FRAP method was measured in extrudates prepared at extrusion parameters: 14% moisture of raw material and 180°C but the lowest at 20% moisture and 120°C. The analysis of spin label reduction kinetics (in EPR method allowed to conclude, that its reduction was greater for extrudates (except extrudates obtained at moisture content 20% and 120°C as compared to raw material. Conclusions. Content of polyphenols and antioxidative activity of rye extrudates is highly dependant on the moisture content of raw material and extrusion temperature.

  19. Impact of Hydrophobicity on Antioxidant Efficacy in Low-Moisture Food.

    Science.gov (United States)

    Barden, Leann; Barouh, Nathalie; Villeneuve, Pierre; Decker, Eric

    2015-06-24

    The polarity and partitioning of antioxidants (AOX) in lipid dispersions and bulk oils have a large impact on efficacy, but this has not yet been studied in low-moisture foods. Using a homologous series of rosmarinic esters as AOX in crackers, we determined that efficacy increases with increasing hydrophobicity based on lipid hydroperoxide and hexanal generation. Confocal microscopy was used to determine the location of both lipids and AOX. Hydrophobic rosmarinic esters partitioned more closely with the lipid than rosmarinic acid, presumably placing the hydrophobic AOX at the site of oxidation reactions. Partitioning and efficacy of the intermediate polarity ester were affected by mode of incorporation (e.g., added to the water or to the lipid prior to dough formation). The synthetic AOXs propyl gallate, butylhydroxytoluene, and tert-butylhydroquinone gave similar results with the more hydrophobic BHT and TBHQ being more effective at reducing lipid hydroperoxide and hexanal generation than the more hydrophilic propyl gallate. These results provide important information on which AOX would be most effective in low-moisture foods. PMID:26039572

  20. Impact of Antioxidants on Cardiolipin Oxidation in Liposomes: Why Mitochondrial Cardiolipin Serves as an Apoptotic Signal?

    Science.gov (United States)

    Lokhmatikov, Alexey V.; Voskoboynikova, Natalia; Cherepanov, Dmitry A.; Skulachev, Maxim V.; Steinhoff, Heinz-Jürgen; Skulachev, Vladimir P.; Mulkidjanian, Armen Y.

    2016-01-01

    Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane—liposomes of pure bovine heart CL—we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively. The kinetics of CL oxidation was monitored via formation of conjugated dienes at 234 nm. We found that natural ubiquinols and ubiquinol-based amphiphilic antioxidants were equally efficient in protecting CL liposomes from peroxidation; the chromanol-based antioxidants, including alpha-tocopherol, were 2-3 times less efficient. Amphiphilic antioxidants, but not natural ubiquinols and alpha-tocopherol, were able, additionally, to protect the CL bilayer from oxidation by acting from the water phase. We suggest that the previously reported therapeutic efficiency of mitochondrially targeted amphiphilic antioxidants is owing to their ability to protect those CL molecules that are inaccessible to natural hydrophobic antioxidants, being trapped within respiratory supercomplexes. The high susceptibility of such occluded CL molecules to oxidation may have prompted their recruitment as apoptotic signaling molecules by nature. PMID:27313834

  1. Antidiabetic and Antioxidant Impacts of Desert Date (Balanites aegyptiaca) and Parsley (Petroselinum sativum) Aqueous Extracts: Lessons from Experimental Rats

    OpenAIRE

    Abou Khalil, Nasser S.; Alaa S. Abou-Elhamd; Wasfy, Salwa I. A.; El Mileegy, Ibtisam M. H.; Hamed, Mohamed Y.; Ageely, Hussein M

    2016-01-01

    Medicinal plants are effective in controlling plasma glucose level with minimal side effects and are commonly used in developing countries as an alternative therapy for the treatment of type 1 diabetes mellitus. The aim of this study is to evaluate the potential antidiabetic and antioxidant impacts of Balanites aegyptiaca and Petroselinum sativum extracts on streptozotocin-induced diabetic and normal rats. The influences of these extracts on body weight, plasma glucose, insulin, total antioxi...

  2. Effect of a single large impact on the coupled atmosphere-interior evolution of Venus

    Science.gov (United States)

    Gillmann, Cédric; Golabek, Gregor J.; Tackley, Paul J.

    2016-04-01

    We investigate the effect of a single large impact either during the Late Veneer or Late Heavy Bombardment on the evolution of the mantle and atmosphere of Venus. We use a coupled interior/exterior numerical code based on StagYY developed in Gillmann and Tackley (Gillmann, C., Tackley, P.J. [2014]. J. Geophys. Res. 119, 1189-1217). Single vertical impacts are simulated as instantaneous events affecting both the atmosphere and mantle of the planet by (i) eroding the atmosphere, causing atmospheric escape and (ii) depositing energy in the crust and mantle of the planet. The main impactor parameters include timing, size/mass, velocity and efficiency of energy deposition. We observe that impact erosion of the atmosphere is a minor effect compared to melting and degassing triggered by energy deposition in the mantle and crust. We are able to produce viable pathways that are consistent with present-day Venus, especially considering large Late Veneer Impacts. Small collisions (<100 km radius) have only local and transient effects. Medium-sized impactors (100-400 km) do not have much more consequence unless the energy deposition is enhanced, for example by a fast collision. In that case, they have comparable effects to the largest category of impacts (400-800 km): a strong thermal anomaly affecting both crust and mantle and triggering melting and a change in mantle dynamics patterns. Such an impact is a global event and can be responsible for volcanic events focused at the impact location and near the antipode. Depending on the timing of the impact, it can also have major consequences for the long-term evolution of the planet and its surface conditions by either (i) efficiently depleting the upper mantle of the planet, leading to the early loss of its water or (ii) imposing a volatile-rich and hot atmosphere for billions of years.

  3. Impact of oceanic circulation changes on atmospheric δ13CO2

    Science.gov (United States)

    Menviel, L.; Mouchet, A.; Meissner, K. J.; Joos, F.; England, M. H.

    2015-12-01

    δ13CO2 measured in Antarctic ice cores provides constraints on oceanic and terrestrial carbon cycle processes linked with millennial-scale and glacial/interglacial changes in atmospheric CO2. However, the interpretation of δ13CO2 is not straightforward. Using two Earth system models of intermediate complexity we perform a set of sensitivity experiments in which the formation rates of North Atlantic Deep Water (NADW), North Pacific Deep Water (NPDW), Antarctic Bottom Water (AABW) and Antarctic Intermediate Water (AAIW) are varied. We study the impact of these circulation changes on atmospheric δ13CO2 as well as on the oceanic δ13C distribution. In general, we find that the formation rates of AABW, NADW, NPDW and AAIW are negatively correlated with changes in δ13CO2: namely strong oceanic ventilation decreases atmospheric δ13CO2. However, since large scale ocean circulation reorganizations also impact nutrient utilization and the Earth's climate the relationship between atmospheric δ13CO2 levels and ocean ventilation rate is not unequivocal. In both models atmospheric δ13CO2 is very sensitive to changes in AABW formation rates: increased AABW formation enhances the upwelling of low δ13C waters to the surface and decreases atmospheric δ13CO2. By contrast, the impact of NADW changes on atmospheric δ13CO2 is less robust and might be model dependent.

  4. Exposure or release of ferulic acid from wheat aleurone: impact on its antioxidant capacity.

    Science.gov (United States)

    Rosa, Natalia N; Dufour, Claire; Lullien-Pellerin, Valérie; Micard, Valérie

    2013-12-01

    The relationship between the aleurone cell integrity and the exposure or release of bioavailable ferulic acid (FA) with the antioxidant capacity of aleurone in in vitro and under simulated gastric conditions was explored. The antioxidant capacity of aleurone was increased by around 2-fold when its median particle size was reduced to under 50 μm. The opening of aleurone cells increased the physical exposure of FA bound to the insoluble polysaccharides, which seemed to be responsible of the increased antioxidant capacity. Synergistic combination of xylanase and feruloyl esterase was found to be the most efficient enzymatic treatment releasing up to 86% of total FA in bioaccessible forms. This enzymatic treatment significantly enhanced the radical scavenging activity of aleurone by up to 4-fold, which overlapped the overall antioxidant potential estimated from the total content of FA in aleurone. The improvement in the antioxidant capacity of aleurone was also observed in the simulated gastric digestion by inhibition of lipid oxidation.

  5. Interactions between Carotenoids from Marine Bacteria and Other Micronutrients: Impact on Stability and Antioxidant Activity.

    Science.gov (United States)

    Sy, Charlotte; Dangles, Olivier; Borel, Patrick; Caris-Veyrat, Catherine

    2015-11-19

    Recently isolated spore-forming pigmented marine bacteria Bacillus indicus HU36 are sources of oxygenated carotenoids with original structures (about fifteen distinct yellow and orange pigments with acylated d-glucosyl groups). In this study, we evaluated the stability (sensitivity to iron-induced autoxidation) and antioxidant activity (inhibition of iron-induced lipid peroxidation) of combinations of bacterial HU36 carotenoids with the bacterial vitamin menaquinone MQ-7 and with phenolic antioxidants (vitamin E, chlorogenic acid, rutin). Unexpectedly, MQ-7 strongly improves the ability of HU36 carotenoids to inhibit Fe(II)-induced lipid peroxidation, although MQ-7 was not consumed in the medium. We propose that their interaction modifies the carotenoid antioxidant mechanism(s), possibly by allowing carotenoids to scavenge the initiating radicals. For comparison, β-carotene and lycopene in combination were shown to exhibit a slightly higher stability toward iron-induced autoxidation, as well as an additive antioxidant activity as compared to the carotenoids, individually. HU36 carotenoids and phenolic antioxidants displayed synergistic activities in the inhibition of linoleic acid peroxidation induced by heme iron, but not by free iron. Synergism could arise from antioxidants interacting via electron transfer through the porphyrin nucleus of heme iron. Overall, combining antioxidants acting via complementary mechanisms could be the key for optimizing the activity of this bacterial carotenoid cocktail.

  6. Recharge of the early atmosphere of Mars by impact-induced release of CO2

    Science.gov (United States)

    Carr, Michael H.

    1989-01-01

    The question as to whether high impact rates early in the history of Mars could have aided in maintaining a relatively thick CO2 atmosphere is discussed. Such impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by the addition of carbon to Mars from the impacting bolides. On the assumption that cratering rates on Mars were comparable to those of the moon's Nectarial period, burial rates are a result of 'impact gardening' at the end of heavy bombardment are estimated to have ranged from 20 to 45 m/million years; at these rates, 0.1-0.2 bar of CO2 would have been released every 10 million years as a result of burial to depths at which carbonate dissociation temperatures are encountered.

  7. Proceedings of impact of aircraft emissions upon the atmosphere. V. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The study of the effect of aircraft on atmosphere is a new challenge that the scientific community has to face. This conference`s topics are various aspects of this challenge. The poster sessions of Volume 2 accompanying sessions 1 through 7 contain various aspects of aerosols, contrails, instruments, measurements, modelling, climatic impacts, projects, transport, atmospheric chemistry etc. The 49 papers of Vol.2. were indexed and abstracted individually for the Energy Database. (R.P.)

  8. Alkyl chain length impacts the antioxidative effect of lipophilized ferulic acid in fish oil enriched milk

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Lyneborg, Karina Sieron; Villeneuve, Pierre;

    2015-01-01

    Lipophilization of phenolics by esterification with fatty alcohols may alter their localization in an emulsion and thereby their antioxidant efficacy. In this study, synthesized unbranched alkyl ferulates were evaluated as antioxidants in fish oil enriched milk. Lipid oxidation was determined...... by peroxide values and concentration of volatile oxidation products. A cut-off effect in the antioxidant efficacy in relation to the alkyl chain length was observed. The most efficient alkyl ferulate was methyl ferulate followed by ferulic acid and butyl ferulate, whereas octyl ferulate was prooxidative...

  9. Impact of sea ice cover changes on the Northern Hemisphere atmospheric winter circulation

    Directory of Open Access Journals (Sweden)

    D. Handorf

    2012-01-01

    Full Text Available The response of the Arctic atmosphere to low and high sea ice concentration phases based on European Center for Medium-Range Weather Forecast (ECMWF Re-Analysis Interim (ERA-Interim atmospheric data and Hadley Centre's sea ice dataset (HadISST1 from 1989 until 2010 has been studied. Time slices of winter atmospheric circulation with high (1990–2000 and low (2001–2010 sea ice concentration in the preceding August/September have been analysed with respect to tropospheric interactions between planetary and baroclinic waves. It is shown that a changed sea ice concentration over the Arctic Ocean impacts differently the development of synoptic and planetary atmospheric circulation systems. During the low ice phase, stronger heat release to the atmosphere over the Arctic Ocean reduces the atmospheric vertical static stability. This leads to an earlier onset of baroclinic instability that further modulates the non-linear interactions between baroclinic wave energy fluxes on time scales of 2.5–6 d and planetary scales of 10–90 d. Our analysis suggests that Arctic sea ice concentration changes exert a remote impact on the large-scale atmospheric circulation during winter, exhibiting a barotropic structure with similar patterns of pressure anomalies at the surface and in the mid-troposphere. These are connected to pronounced planetary wave train changes notably over the North Pacific.

  10. Atmospheric Variability of CO2 impact on space observation Requirements

    Science.gov (United States)

    Swanson, A. L.; Sen, B.; Newhart, L.; Segal, G.

    2009-12-01

    If International governments are to reduce GHG levels by 80% by 2050, as recommended by most scientific bodies concerned with avoiding the most hazardous changes in climate, then massive investments in infrastructure and new technology will be required over the coming decades. Such an investment will be a huge commitment by governments and corporations, and while it will offer long-term dividends in lower energy costs, a healthier environment and averted additional global warming, the shear magnitude of upfront costs will drive a call for a monitoring and verification system. Such a system will be required to offer accountability to signatories of governing bodies, as well as, for the global public. Measuring the average global distribution of CO2 is straight forward, as exemplified by the long running station measurements managed by NOAA’s Global Monitoring Division that includes the longterm Keeling record. However, quantifying anthropogenic and natural source/sink distributions and atmospheric mixing have been much more difficult to constrain. And, yet, an accurate accounting of all anthropogenic source strengths is required for Global Treaty verification. The only way to accurately assess Global GHG emissions is to construct an integrated system of ground, air and space based observations with extensive chemical modeling capabilities. We look at the measurement requirements for the space based component of the solutions. To determine what space sensor performance requirements for ground resolution, coverage, and revisit, we have analyzed regional CO2 distributions and variability using NASA and NOAA aircraft flight campaigns. The results of our analysis are presented as variograms showing average spatial variability over several Northern Hemispheric regions. There are distinct regional differences with the starkest contrast between urban versus rural and Coastal Asia versus Coastal US. The results suggest specific consequences on what spatial and temporal

  11. Impact of clouds and precipitation on atmospheric aerosol

    Science.gov (United States)

    Andronache, Constantin

    2015-04-01

    Aerosols have a significant impact on the dynamics and microphysics of continental mixed-phase convective clouds. High aerosol concentrations provide enhanced cloud condensation nuclei that can lead to the invigoration of convection and increase of surface rainfall. Such effects are dependent on environmental conditions and aerosol properties. Clouds are not only affected by aerosol, they also alter aerosol properties by various processes. Cloud processing of aerosol includes: convective redistribution, modification in the number and size of aerosol particles, chemical processing, new particle formation around clouds, and aerosol removal by rainfall to the surface. Among these processes, the wet removal during intense rain events, in polluted continental regions, can lead to spikes in acidic deposition into environment. In this study, we address the effects of clouds and precipitation on the aerosol distribution in cases of convective precipitation events in eastern US. We examine the effects of clouds and precipitation on various aerosol species, as well as their temporal and spatial variability.

  12. Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity

    Science.gov (United States)

    Martino, M.; Hamilton, D.; Baker, A. R.; Jickells, T. D.; Bromley, T.; Nojiri, Y.; Quack, B.; Boyd, P. W.

    2014-07-01

    The atmospheric deposition of both macronutrients and micronutrients plays an important role in driving primary productivity, particularly in the low-latitude ocean. We report aerosol major ion measurements for five ship-based sampling campaigns in the western Pacific from ~25°N to 20°S and compare the results with those from Atlantic meridional transects (~50°N to 50°S) with aerosols collected and analyzed in the same laboratory, allowing full incomparability. We discuss sources of the main nutrient species (nitrogen (N), phosphorus (P), and iron (Fe)) in the aerosols and their stoichiometry. Striking north-south gradients are evident over both basins with the Northern Hemisphere more impacted by terrestrial dust sources and anthropogenic emissions and the North Atlantic apparently more impacted than the North Pacific. We estimate the atmospheric supply rates of these nutrients and the potential impact of the atmospheric deposition on the tropical western Pacific. Our results suggest that the atmospheric deposition is P deficient relative to the needs of the resident phytoplankton. These findings suggest that atmospheric supply of N, Fe, and P increases primary productivity utilizing some of the residual excess phosphorus (P*) in the surface waters to compensate for aerosol P deficiency. Regional primary productivity is further enhanced via the stimulation of nitrogen fixation fuelled by the residual atmospheric iron and P*. Our stoichiometric calculations reveal that a P* of 0.1 µmol L-1 can offset the P deficiency in atmospheric supply for many months. This study suggests that atmospheric deposition may sustain ~10% of primary production in both the western tropical Pacific.

  13. Study on the atmospheric component with the scope of analyses on the environmental impact

    International Nuclear Information System (INIS)

    This work has been carried out following a specific request from Italian National Department for Environment and shows technical approaches and methodologies of analyses and forecasts set up for environmental impact studies referred to 'atmospheric environment'. This work is presented according to the general items and objectives fixed by the same Department in the wider operative system for the application in Italy of environmental impact procedures. (author)

  14. Assessing the impact of crops on regional CO{sub 2} fluxes and atmospheric concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Corbin, K. D. (Commonwealth Scientific and Industrial Research Organization (CSIRO), Marine and Atmospheric Research, Aspendale (Australia)), e-mail: katherine.corbin@csiro.au; Denning, A. S.; Lokupitiya, E. Y.; Schuh, A. E.; Baker, I. T. (Dept. of Atmospheric Science, Colorado State Univ., Fort Collins, CO (United States)); Miles, N. L.; Davis, K. J.; Richardson, S. (Dept. of Meteorology, Pennsylvania State Univ., University Park, PA (United States))

    2010-11-15

    Human conversion of natural ecosystems to croplands modifies not only the exchange of water and energy between the surface and the atmosphere, but also carbon fluxes. To investigate the impacts of crops on carbon fluxes and resulting atmospheric CO{sub 2} concentrations in the mid-continent region of the United States, we coupled a crop-specific phenology and physiology scheme for corn, soybean and wheat to the coupled ecosystem-atmosphere model SiB3-RAMS. Using SiBcrop-RAMS improved carbon fluxes at the local scale and had regional impacts, decreasing the spring uptake and increasing the summer uptake over the mid-continent. The altered fluxes changed the mid-continent atmospheric CO{sub 2} concentration field at 120 m compared to simulations without crops: concentrations increased in May and decreased >20 ppm during July and August, summer diurnal cycle amplitudes increased, synoptic variability correlations improved and the gradient across the mid-continent region increased. These effects combined to reduce the squared differences between the model and high-precision tower CO{sub 2} concentrations by 20%. Synoptic transport of the large-scale N-S gradient caused significant day-to-day variability in concentration differences measured between the towers. This simulation study shows that carbon exchange between crops and the atmosphere significantly impacts regional CO{sub 2} fluxes and concentrations

  15. Impact of atmospheric deposition of As, Cd and Pb on their concentration in carrot and celeriac

    International Nuclear Information System (INIS)

    Root crops, carrot and celeriac, were exposed to atmospheric deposition in a polluted versus reference area. An effect was observed on the As, Cd and Pb concentrations of the leaves and the storage organs. The concentrations in the whole storage organs correlated well with atmospheric deposition, which shows that they even could be used for biomonitoring. Nevertheless, leaves remain much more appropriate. The results revealed also a significant increase of the As and Cd concentration in the consumable part of the storage organs as a function of their atmospheric deposition. As such the experiments allowed deriving regression equations, useful for modeling the atmospheric impact of trace elements on the edible parts of root crops. For Pb, however, there was hardly any significant impact on the inner parts of the storage organs and as such the transfer of Pb in the food chain through root crops can be considered to be negligible. - Highlights: ► This paper is exploring new ideas on biomonitoring. ► Some airborne trace elements are transported to unexposed plant parts. ► Storage organs accumulate also airborne trace elements. ► Biomonitoring is useful to study the transfer of trace elements in the food chain. - Biomonitoring as a tool to study the impact of atmospherically deposited trace elements on the food chain.

  16. The Atmospheres of Earth-like Planets after Giant Impact Events

    CERN Document Server

    Lupu, R E; Marley, Mark S; Schaefer, Laura; Fegley, Bruce; Morley, Caroline; Cahoy, Kerri; Freedman, Richard; Fortney, Jonathan J

    2014-01-01

    It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well known example. In the aftermath of such collisions the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO2, and H2O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H2O and CO2, while the formation of CH4, and NH3 is quenched due to short dynamical timescales. Other important constituents are HF, HCl, NaCl, an...

  17. Heterogeneity of atmospheric ammonia at the landscape scale and consequences for environmental impact assessment.

    Science.gov (United States)

    Vogt, Esther; Dragosits, Ulrike; Braban, Christine F; Theobald, Mark R; Dore, Anthony J; van Dijk, Netty; Tang, Y Sim; McDonald, Chris; Murray, Scott; Rees, Robert M; Sutton, Mark A

    2013-08-01

    We examined the consequences of the spatial heterogeneity of atmospheric ammonia (NH₃) by measuring and modelling NH₃ concentrations and deposition at 25 m grid resolution for a rural landscape containing intensive poultry farming, agricultural grassland, woodland and moorland. The emission pattern gave rise to a high spatial variability of modelled mean annual NH₃ concentrations and dry deposition. Largest impacts were predicted for woodland patches located within the agricultural area, while larger moorland areas were at low risk, due to atmospheric dispersion, prevailing wind direction and low NH3 background. These high resolution spatial details are lost in national scale estimates at 1 km resolution due to less detailed emission input maps. The results demonstrate how the spatial arrangement of sources and sinks is critical to defining the NH₃ risk to semi-natural ecosystems. These spatial relationships provide the foundation for local spatial planning approaches to reduce environmental impacts of atmospheric NH₃.

  18. Two- and Three-dimensional simulations of atmospheric erosion by impacts

    Science.gov (United States)

    Korycansky, D. G.; Zahnle, Kevin J.; Catling, David C.

    2015-11-01

    One of the key features of Earth-sized planets in this and other systems is the presence or absence of an atmosphere. A mechanism for atmsopheric loss post-formation is erosion by hypervelocity impacts by massive objects. We are carrying out simulations of the effects of hypervelocity impacts with the aim of assessing the efficiency of the process and disentangling the effects of impact erosion from other mechanisms such as thermal escape. For our overall project, we consider three types of planets: Mars-type, Earth-type, and a "super-Earth" (8 M_earth). Surface atmospheric pressures are 1, 10, and 100 bars. Three diameters of impactors are considered (4.6, 17, and 36.8 km) with impact velocities of 2, 4, 6, and 8 times the escape velocity of the target. Impact simulations can be divided between "local" and "global" cases depending on the geometry of the impact, chiefly the impactor size relative to the target planet and the depth of the atmosphere compared to the planet's radius. The calculations discussed here are local: the curvature of the planet and the radial dependence of the gravitational field are neglected. The impact simulations are carried out with the CTH code, developed at Sandia National Laboratory. CTH is a highly advanced code widely used in the planetary science community. It utilizes adaptive mesh refinement to concentrate computational resources at locations of physical interest in the simulation, such as shockfronts and material interfaces. It makes use of material strength models and advanced tabular equations of state such as ANEOS and the SESAME library. Post-impact analysis yields fluxes of material moving at escape speed or faster through the boundaries (chiefly the upper boundary at the exobase); we integrate the flux to get the total amount of escaping material. Although we track three kinds of material (impactor, target surface, atmosphere), here we report only on the last (escaping atmosphere). We will present results from 2D and 3D

  19. An experimental and numerical study of the atmospheric stability impact on wind turbine wakes

    DEFF Research Database (Denmark)

    Machefaux, Ewan; Larsen, Gunner Chr.; Koblitz, Tilman;

    2015-01-01

    In this paper, the impact of atmospheric stability on a wind turbine wake is studied experimentally and numerically. The experimental approach is based on full-scale (nacelle based) pulsed lidar measurements of the wake flow field of a stall-regulated 500 kW turbine at the DTU Wind Energy, Risø c...

  20. Impact of oceanic circulation changes on atmospheric δ13CO2

    Science.gov (United States)

    Menviel, L.; Mouchet, A.; Meissner, K. J.; Joos, F.; England, M. H.

    2015-11-01

    δ13CO2 measured in Antarctic ice cores provides constraints on oceanic and terrestrial carbon cycle processes linked with millennial-scale changes in atmospheric CO2. However, the interpretation of δ13CO2 is not straightforward. Using carbon isotope-enabled versions of the LOVECLIM and Bern3D models, we perform a set of sensitivity experiments in which the formation rates of North Atlantic Deep Water (NADW), North Pacific Deep Water (NPDW), Antarctic Bottom Water (AABW), and Antarctic Intermediate Water (AAIW) are varied. We study the impact of these circulation changes on atmospheric δ13CO2 as well as on the oceanic δ13C distribution. In general, we find that the formation rates of AABW, NADW, NPDW, and AAIW are negatively correlated with changes in δ13CO2: namely, strong oceanic ventilation decreases atmospheric δ13CO2. However, since large-scale oceanic circulation reorganizations also impact nutrient utilization and the Earth's climate, the relationship between atmospheric δ13CO2 levels and ocean ventilation rate is not unequivocal. In both models atmospheric δ13CO2 is very sensitive to changes in AABW formation rates: increased AABW formation enhances the transport of low δ13C waters to the surface and decreases atmospheric δ13CO2. By contrast, the impact of NADW changes on atmospheric δ13CO2 is less robust and might be model dependent. This results from complex interplay between global climate, carbon cycle, and the formation rate of NADW, a water body characterized by relatively high δ13C.

  1. Impact of tributyltin on antioxidant and DNA damage response in spermatozoa of freshwater prawn Macrobrachium rosenbergii.

    Science.gov (United States)

    Rani, K Umaa; Musthafa, M Saiyad; War, Mehrajuddin; Al-Sadoon, Mohammad K; Paray, Bilal Ahmad; Shareef, T H Mohamed Ahadhu; Nawas, P Mohideen Askar

    2015-12-01

    Effects of tributyltin (TBT) on antioxidant [total superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR)] and DNA damage levels in the spermatozoa were studied and reported here for the first time in the freshwater prawn Macrobrachium rosenbergii. Three groups of (n = 10 in each group) fishes were exposed to three different nominal concentrations of TBT viz., 1, 2, and 4 mg L(-1) along with control group for 90 days. Significant decrease of antioxidant and increased DNA damage levels were seen at higher doses of 2 and 4 mg L(-1). In prawn, the antioxidant level plays a vital role in sperm protection, activation, differential functions related to the physiology, and reproductive behavior. This study serves as a biomonitoring tool to assess the TBT effects on reproductive behavior of aquatic biota.

  2. THE IMPACT OF ENVIRONMENTALLY FRIENDLY POSTHARVEST TREATMENTS ON THE ANTIOXIDANT ACTIVITY OF STRAWBERRY FRUITS DURING STORAGE

    Directory of Open Access Journals (Sweden)

    Ivna Štolfa

    2014-12-01

    Full Text Available Proper postharvest storage is an effective way to maintain the quality and nutritional values of fruits. The aim of this study was to determine how environmentally friendly postharvest treatments with salicylic acid solution, colloidal silver solution and ozone, affect the antioxidant activity of strawberry fruits (Fragaria x ananassa Duch. cv. Albion during 7 days of storage at 4°C. The content of ascorbic acid, total phenols and antioxidant activity of strawberry fruits were determined spec-trophotometrically. After 7 days of storage in strawberry fruits treated with all three treatments separately, the contents of ascorbic acid were higher than in the control fruits, supporting the usefulness of these treatments for preserving fruit quality and nutritional value during storage. The treatment with salicylic acid solution showed the most beneficial effect during storage causing a significant increase in the content of ascorbic acid, phenols and antioxidant activity at the end of the storage period.

  3. Antioxidant activity of bulbs and aerial parts of Crocus caspius, impact of extraction methods.

    Science.gov (United States)

    Khalili, Masomeh; Fathi, Hamed; Ebrahimzadeh, Mohammad Ali

    2016-05-01

    Crocus genus (Iridaceae) is comprises approximately 80 species. In this study in vitro antioxidant activities of extracts from C. caspius bulbs and aerial parts were investigated. Ultrasonically assisted extraction (US), percolation method (PE) and polyphenolic fraction (PP) were used. Antioxidant activities were evaluated with five different tests. Aerial parts US extract with high levels of phenol and flavonoids were the most potent extract in DPPH radical scavenging than others. Aerial parts PE extract had shown very potent reducing power, which was so better than other extracts (p<0.01). Aerial parts PP fraction showed very good Fe(2+) chelating ability. Aerial parts US extract were the most potent extract in scavenging of H(2)O(2). Bulb PP fraction with IC(50)=22.8±0.7 µg ml(-1) was the most potent fraction in nitric oxide scavenging. The results improved high levels of antioxidant activities of C. caspius bulbs and aerial parts in all tested models.

  4. Impact of different drying parameters on color, β-carotene, antioxidant activity and minerals of apricot (Prunus armeniacaL.

    Directory of Open Access Journals (Sweden)

    Bige İNCEDAYI

    2016-03-01

    Full Text Available Abstract Apricot is one of the fruits dried by using different methods, such as sun, convective or microwave drying. The effects of drying methods on the components of this fruit differ depending upon the temperature or time parameters. In this research, the impacts of convective, microwave and microwave–convective drying techniques on color, β-carotene, minerals and antioxidant activity of apricots were investigated. The color values (L*, b*,ΔEab, h° and C*ab of dried fruit were decreased, while the a* values increased. Compared with a fresh sample, the dried apricots showed a 1.4-3.9-fold proportional increase in β-carotene based on the increment of dry matter. The samples dried at high temperature and microwave levels, at 75 °C+90 watt and 75 °C+160 watt, showed lower antioxidant activity. Of the different drying treatments, the microwave-convective method (50 °C+160 watt obtained a higher β-carotene content while maintaining antioxidant activity with a short drying time.

  5. Antidiabetic and Antioxidant Impacts of Desert Date (Balanites aegyptiaca and Parsley (Petroselinum sativum Aqueous Extracts: Lessons from Experimental Rats

    Directory of Open Access Journals (Sweden)

    Nasser S. Abou Khalil

    2016-01-01

    Full Text Available Medicinal plants are effective in controlling plasma glucose level with minimal side effects and are commonly used in developing countries as an alternative therapy for the treatment of type 1 diabetes mellitus. The aim of this study is to evaluate the potential antidiabetic and antioxidant impacts of Balanites aegyptiaca and Petroselinum sativum extracts on streptozotocin-induced diabetic and normal rats. The influences of these extracts on body weight, plasma glucose, insulin, total antioxidant capacity (TAC, malondialdehyde (MDA levels, and liver-pyruvate kinase (L-PK levels were assessed. Furthermore, the weight and histomorphological changes of the pancreas were studied in the different experimental groups. The herbal preparations significantly reduced the mean plasma glucose and MDA levels and significantly increased the mean plasma insulin, L-PK, and TAC levels in the treated diabetic groups compared to the diabetic control group. An obvious increase in the weight of the pancreas and the size of the islets of Langerhans and improvement in the histoarchitecture were evident in the treated groups compared to untreated ones. In conclusion, the present study provides a scientific evidence for the traditional use of these extracts as antidiabetic and antioxidant agents in type 1 diabetes mellitus.

  6. Antidiabetic and Antioxidant Impacts of Desert Date (Balanites aegyptiaca) and Parsley (Petroselinum sativum) Aqueous Extracts: Lessons from Experimental Rats.

    Science.gov (United States)

    Abou Khalil, Nasser S; Abou-Elhamd, Alaa S; Wasfy, Salwa I A; El Mileegy, Ibtisam M H; Hamed, Mohamed Y; Ageely, Hussein M

    2016-01-01

    Medicinal plants are effective in controlling plasma glucose level with minimal side effects and are commonly used in developing countries as an alternative therapy for the treatment of type 1 diabetes mellitus. The aim of this study is to evaluate the potential antidiabetic and antioxidant impacts of Balanites aegyptiaca and Petroselinum sativum extracts on streptozotocin-induced diabetic and normal rats. The influences of these extracts on body weight, plasma glucose, insulin, total antioxidant capacity (TAC), malondialdehyde (MDA) levels, and liver-pyruvate kinase (L-PK) levels were assessed. Furthermore, the weight and histomorphological changes of the pancreas were studied in the different experimental groups. The herbal preparations significantly reduced the mean plasma glucose and MDA levels and significantly increased the mean plasma insulin, L-PK, and TAC levels in the treated diabetic groups compared to the diabetic control group. An obvious increase in the weight of the pancreas and the size of the islets of Langerhans and improvement in the histoarchitecture were evident in the treated groups compared to untreated ones. In conclusion, the present study provides a scientific evidence for the traditional use of these extracts as antidiabetic and antioxidant agents in type 1 diabetes mellitus. PMID:27019854

  7. Functionalized Mesoporous Silica Nanoparticle with Antioxidants as a New Carrier That Generates Lower Oxidative Stress Impact on Cells.

    Science.gov (United States)

    Ebabe Elle, Raymond; Rahmani, Saher; Lauret, Céline; Morena, Marion; Bidel, Luc Philippe Régis; Boulahtouf, Abdelhay; Balaguer, Patrick; Cristol, Jean-Paul; Durand, Jean-Olivier; Charnay, Clarence; Badia, Eric

    2016-08-01

    Mesoporous silica nanoparticles (MSNs) were covalently coated with antioxidant molecules, namely, caffeic acid (MSN-CAF) or rutin (MSN-RUT), in order to diminish the impact of oxidative stress induced after transfection into cells, thus generating safer carriers used for either drug delivery or other applications. Two cellular models involved in the entry of NPs in the body were used for this purpose: the intestinal Caco-2 and the epidermal HaCaT cell lines. Rutin gave the best results in terms of antioxidant capacities preservation during coupling procedures, cellular toxicity alleviation, and decrease of ROS level after 24 h incubation of cells with grafted nanoparticles. These protective effects of rutin were found more pronounced in HaCaT than in Caco-2 cells, indicating some cellular specificity toward defense against oxidative stress. In order to gain more insight about the Nrf2 response, a stable transfected HaCaT cell line bearing repeats of the antioxidant response element (ARE) in front of a luciferase reporter gene was generated. In this cell line, both tBHQ and quercetin (Nrf2 agonists), but not rutin, were able to induce, in a dose-dependent fashion, the luciferase response. Interestingly, at high concentration, MSN-RUT was able to induce a strong Nrf2 protective response in HaCaT cells, accompanied by a comparable induction of HO-1 mRNA. The level of these responses was again less important in Caco-2 cells. To conclude, in keratinocyte cell line, the coupling of rutin to silica nanoparticles was beneficial in term of ROS reduction, cellular viability, and protective effects mediated through the activation of the Nrf2 antioxidant pathway.

  8. Impacts of elevated atmospheric CO2 and O3 on forests: phytochemistry, trophic interactions, and ecosystem dynamics.

    Science.gov (United States)

    Lindroth, Richard L

    2010-01-01

    Prominent among the many factors now affecting the sustainability of forest ecosystems are anthropogenically-generated carbon dioxide (CO2) and ozone (O3). CO2 is the substrate for photosynthesis and thus can accelerate tree growth, whereas O3 is a highly reactive oxygen species and interferes with basic physiological functions. This review summarizes the impacts of CO2 and O3 on tree chemical composition and highlights the consequences thereof for trophic interactions and ecosystem dynamics. CO2 and O3 influence phytochemical composition by altering substrate availability and biochemical/physiological processes such as photosynthesis and defense signaling pathways. Growth of trees under enriched CO2 generally leads to an increase in the C/N ratio, due to a decline in foliar nitrogen and concomitant increases in carbohydrates and phenolics. Terpenoid levels generally are not affected by atmospheric CO2 concentration. O3 triggers up-regulation of antioxidant defense pathways, leading to the production of simple phenolics and flavonoids (more so in angiosperms than gymnosperms). Tannins levels generally are unaffected, while terpenoids exhibit variable responses. In combination, CO2 and O3 exert both additive and interactive effects on tree chemical composition. CO2-and O3-mediated changes in plant chemistry influence host selection, individual performance (development, growth, reproduction), and population densities of herbivores (primarily phytophagous insects) and soil invertebrates. These changes can effect shifts in the amount and temporal pattern of forest canopy damage and organic substrate deposition. Decomposition rates of leaf litter produced under elevated CO2 and O3 may or may not be altered, and can respond to both the independent and interactive effects of the pollutants. Overall, however, CO2 and O3 effects on decomposition will be influenced more by their impacts on the quantity, rather than quality, of litter produced. A prominent theme to emerge

  9. Antioxidant potential of herbs extracts and impact on HepG2 cells viability

    Directory of Open Access Journals (Sweden)

    Anna Gramza-Michałowska

    2008-12-01

    Full Text Available Mercury poisoning is responsible for inducing serious adverse effects in living organisms. One of protection factors could be substances proven to possess high antioxidant and metal chelating activity – plant polyphenols. There are many sources of polyphenols in plant kingdom but the most interesting for food industry could be widely consumed herbs. Aim of the research was to evaluate antioxidative potential of selected plant extracts and its influence on HepG2 cells in different conditions. Ethanolic herbs extracts were characterised by total polyphenol content. Antioxidant activity was estimated with use of DPPH• and ABTS+• radicals scavenging methods and FRAP. Research included cells viability estimation by the MTT assay and cells exposition to HgCl2, chemical agent inducing cell death. Analysis of herbs extracts antioxidative activity showed best potential represented thyme and marjoram, highest FRAP was evaluated in samples with mint and marjoram extracts. On the basis of received results it was found that examined plant extracts showed weak protection against Hg presence in examined cells environment.

  10. Effects of hydrodynamics and thermal radiation in the atmosphere after comet impacts

    Science.gov (United States)

    Nemchinov, I. V.; Popova, M. P.; Shubadeeva, L. P.; Shuvalov, V. V.; Svetsov, V. V.

    1993-01-01

    Radiation phenomena in the atmosphere after impacts of cosmic bodies have special features in comparison with the surface nuclear explosions. First, initial concentration of energy after the impact is lower, and second, a wake after the passage of the meteoroid through the atmosphere has a dramatic effect on the atmospheric flow and radiation transfer. Consequently, scaling laws can not be employed for prediction of the flow in the atmosphere and the light flux on the Earth's surface. If a density of high-velocity impactor is low relative to the ground, as in a case of a comet impact on rocks, a major part of the kinetic energy is converted to internal energy of dense hot vapors. But radiation effects can be essential even for fairly low velocities of the impactor. To clarify this issue we have undertaken calculations of 100-Mt explosions at the Earth's surface caused by small comets with velocities from 10 to 70 km/sec. That is, the initial concentration of energy has been varied. The calculations have shown that for velocities of the comet greater or about 20 km/sec a portion of energy emitted from the fireball exceeds 20% of the total energy of the explosion and this quantity does not change very much with the velocity. Other aspects of this investigation are discussed.

  11. The Climatology and Impacts of Atmospheric Rivers near the Coast of Southern Alaska

    Science.gov (United States)

    Nardi, K.; Barnes, E. A.; Mundhenk, B. D.

    2015-12-01

    Atmospheric rivers, narrow plumes of anomalously high tropospheric water vapor transport, frequently appear over the Pacific Ocean. Popularized by colloquialisms such as the "Pineapple Express," atmospheric rivers often interact with synoptic-scale disturbances to produce significant precipitation events over land masses. Previous research has focused extensively on the impacts of this phenomenon with respect to high-precipitation storms, namely during boreal winter, on the western coast of the contiguous United States. These events generate great scientific, political, and economic concerns for nearby cities, farms, and tourist destinations. Recently, researchers have investigated similar high-precipitation events along the southern coast of Alaska. Specifically, previous work has discussed several major events occurring during the September-November timeframe. One particular event, in October 2006, produced an all-time record for water levels at several river observation sites. This study examines the climatology of atmospheric rivers in the vicinity of southern Alaska. Data (1979-2014) from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) is used to detect atmospheric rivers approaching, and making landfall on, the southern Alaskan coast from the Kenai Peninsula to the Gulf of Alaska region. A seasonal cycle in the strength and frequency of atmospheric rivers over Alaska is shown. Furthermore, the study assesses the synoptic conditions coincident with atmospheric rivers and examines several instances of particularly strong precipitation events. For example, wintertime atmospheric river events tend to occur when a blocking high exists over southeastern Alaska. These results have the potential to help forecasters and emergency managers predict high-precipitation events and lessen potential negative impacts.

  12. Atmospheric emissions and air quality impacts from natural gas production and use.

    Science.gov (United States)

    Allen, David T

    2014-01-01

    The US Energy Information Administration projects that hydraulic fracturing of shale formations will become a dominant source of domestic natural gas supply over the next several decades, transforming the energy landscape in the United States. However, the environmental impacts associated with fracking for shale gas have made it controversial. This review examines emissions and impacts of air pollutants associated with shale gas production and use. Emissions and impacts of greenhouse gases, photochemically active air pollutants, and toxic air pollutants are described. In addition to the direct atmospheric impacts of expanded natural gas production, indirect effects are also described. Widespread availability of shale gas can drive down natural gas prices, which, in turn, can impact the use patterns for natural gas. Natural gas production and use in electricity generation are used as a case study for examining these indirect consequences of expanded natural gas availability. PMID:24498952

  13. Consideration of impact of atmospheric intrusion in subsurface sampling for investigation of suspected underground nuclear explosions

    International Nuclear Information System (INIS)

    Radioactive noble gases radioxenon and radioargon constitute the primary smoking gun of an underground nuclear explosion. The aim of subsurface sampling of soil gas as part of an on-site inspection (OSI) is to search for evidence of a suspected underground nuclear event. It has been hypothesized that atmospheric gas can disturb soil gas concentrations and therefore potentially add to problems in civilian source discrimination verifying treaty compliance under the comprehensive nuclear-test ban treaty. This work describes a study of intrusion of atmospheric air into the subsurface and its potential impact on an OSI using results of simulations from the underground transport of environmental xenon (UTEX) model. (author)

  14. Localization, innovation and entrepreneurship: an appraisal of the analytical impact of Marshall's notion of industrial atmosphere

    OpenAIRE

    Jacques-Laurent Ravix

    2014-01-01

    The purpose of the paper is to appraise the impact of Marshall?s ideas on today?s analysis of localized industrial activities, with a special focus on his vision of the entrepreneur?s action on the emergence of local industrial atmosphere. The first section uses Marshall?s approach to industrial dynamics. This approach articulates knowledge and organization and the role of local actors in the structuring of industrial districts leading to the rise of some peculiar atmospheres. Section two exa...

  15. Impact of electron chemistry on the structure and composition of Io's atmosphere

    Science.gov (United States)

    Smyth, William H.; Wong, M. C.

    2004-09-01

    Two-dimensional model calculations (altitude and solar zenith angle) are performed to investigate the impact of electron chemistry on the composition and structure of Io's atmosphere. The calculations are based upon the model of Wong and Smyth (2000, Icarus 146, 60-74) for Io's SO 2 sublimation atmosphere with the addition of new electron chemistry, where the interactions of the electrons and neutrals are treated in a simple fashion. The model calculations are presented for Io's atmosphere at western elongation (dusk ansa) for both a low-density case (subsolar temperature of 113 K) and a high-density case (subsolar temperature of 120 K). The impact of electron-neutral chemistry on the composition and structure of Io's atmosphere is confined primarily to an interaction layer. The penetration depth of the interaction layer is limited to high altitudes in the thicker dayside atmosphere but reaches the surface in the thinner dayside and/or nightside atmosphere at larger solar zenith angles. Within most of the thicker dayside atmosphere, the column density of SO 2 is not significantly altered by electrons, but in the interaction layer all number densities are significantly altered: SO 2 is reduced, O, SO, S, and O 2 are greatly enhanced, and O, SO, and S become comparable to SO 2 at high altitudes. For the thinner nightside atmosphere, the species number densities are dramatically altered: SO 2 is drastically reduced to the least abundant species of the SO 2 family, SO and O 2 are significantly reduced at all altitudes, and O and S are dramatically enhanced and become the dominant species at all altitudes except near the surface. The interaction layer also defines the location of the emission layer for neutrals excited by electron impact and hence determines the fraction of the total neutral column density that is visible in remote observation. Electron chemistry may also impact the ratio of the equatorial to polar SO 2 column density deduced from Lyman- α images and

  16. The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

    Directory of Open Access Journals (Sweden)

    J. C. McWilliams

    2007-10-01

    Full Text Available Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical biogeochemical ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

  17. Understanding the impact of plant competition on the coupling between vegetation and the atmosphere

    Science.gov (United States)

    Loon, Marloes P.; Dekker, Stefan C.; Anten, Niels P. R.; Rietkerk, Max; Vilà-Guerau de Arellano, Jordi

    2015-11-01

    Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation functioning and associated atmospheric interactions. Our aim was to investigate how the coupling between vegetation and atmosphere is influenced by plant competition. Though included in some coupled vegetation-atmosphere models, little attention has been paid to systematically study the impact of plant competition in determining the evolution of surface and atmospheric variables. We used a coupled vegetation-atmosphere model and included a new representation of plant competition. We compared the model results with diurnal data from Ameriflux Bondville site over a growing season. Including competition improved LAI (Leaf Area Index) and net ecosystem exchange of CO2 (NEE) predictions; if competition was not considered, there were strong deviations from observations. Remarkably, competition increased LAI while it reduced whole stand photosynthesis, resulting in a less negative NEE. Finally, independent of competition, latent heat flux, surface temperature, specific humidity, and atmospheric CO2 are well reproduced by the model. Only the sensible heat flux was overestimated, mainly due to the imbalance in the surface energy balance that can lead to lower measured sensible heat fluxes. Sensitivity analysis showed that the importance of plant competition on model outcomes increases with more nitrogen and water availability and may differ between soil types. We thus quantified the potential effect of plant competition in a coupled vegetation-atmosphere system and showed that it strongly influences this system, and therefore, we propose that competition should be considered in more vegetation-atmosphere models.

  18. Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake

    Directory of Open Access Journals (Sweden)

    A. Oschlies

    2009-04-01

    Full Text Available The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively. On longer than decadal timescales, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization may not come from the atmosphere but from the terrestrial biosphere.

  19. The impact of nitrite and antioxidants on ultraviolet-A-induced cell death of human skin fibroblasts.

    Science.gov (United States)

    Opländer, Christian; Cortese, Miriam M; Korth, Hans-Gert; Kirsch, Michael; Mahotka, Csaba; Wetzel, Wiebke; Pallua, Norbert; Suschek, Christoph V

    2007-09-01

    Nitrite (NO(2)(-)) occurs ubiquitously in biological fluids such as blood and sweat. Ultraviolet A-induced nitric oxide formation via decomposition of cutaneous nitrite, accompanied by the production of reactive oxygen (ROS) or nitrogen species (RNS), represents an important source for NO in human skin physiology. Examining the impact of nitrite and the antioxidants glutathione (GSH), Trolox (TRL), and ascorbic acid (ASC) on UVA-induced toxicity of human skin fibroblasts (FB) we found that NO(2)(-) concentration-dependently enhances the susceptibility of FB to the toxic effects of UVA by a mechanism comprising enhanced induction of lipid peroxidation. While ASC completely protects FB cultures from UVA/NO(2)(-)-induced cell damage, GSH or TRL excessively enhances UVA/NO(2)(-)-induced cell death by a mechanism comprising nitrite concentration-dependent TRL radical formation or GSH-derived oxidative stress. Simultaneously, in the presence of GSH or TRL the mode of UVA/NO(2)(-)-induced cell death changes from apoptosis to necrosis. In summary, during photodecomposition of nitrite, ROS or RNS formation may act as strong toxic insults. Although inhibition of oxidative stress by NO and other antioxidants represents a successful strategy for protection from UVA/NO(2)(-)-induced injuries, GSH and TRL may nitrite-dependently aggravate the injurious impact by TRL or GSH radical formation, respectively.

  20. Suitability of antioxidant capacity, flavonoids and phenolic acids for floral authentication of honey. Impact of industrial thermal treatment.

    Science.gov (United States)

    Escriche, Isabel; Kadar, Melinda; Juan-Borrás, Marisol; Domenech, Eva

    2014-01-01

    Total antioxidant activity, physicochemical parameters, and the profile of flavonoids and phenolic acid compounds were evaluated for: their ability to distinguish between the botanical origins of four types of Spanish honey, the impact of industrial thermal treatment, and the effect of the year of collection. Citrus honey had the lowest levels of all the analysed variables, then rosemary and polyfloral, and honeydew the highest ones. Botanical origin affects the profile of flavonoids and phenolic compounds sufficiently to permit discrimination thanks to the predominance of particular compounds such as: hesperetin (in citrus honey); kaempferol, chrysin, pinocembrin, caffeic acid and naringenin (in rosemary honey) and myricetin, quercetin, galangin and particularly p-coumaric acid (in honeydew honey). The impact of industrial thermal treatments is lower than the expected variability as a consequence of the year of collection, though neither factor has enough influence to alter these constituent compounds to the point of affecting the discrimination of honey by botanical origin. PMID:24001823

  1. Impact of biomass burning on surface water quality in Southeast Asia through atmospheric deposition: field observations

    Science.gov (United States)

    Sundarambal, P.; Balasubramanian, R.; Tkalich, P.; He, J.

    2010-03-01

    Atmospheric nutrients have recently gained attention as a significant additional source of new nitrogen (N) and phosphorus (P) loading to the ocean. The effect of atmospheric N on marine productivity depends on the biological availability of both inorganic and organic N and P forms. During October 2006, the regional smoke haze episode in Southeast Asia (SEA) that resulted from uncontrolled forest fires in Sumatra and Borneo blanketed large tracts of the region. In this work, we determined the composition of nutrients in aerosols and rainwater during haze and non-haze periods to assess their impacts on aquatic ecosystem in SEA for the first time. We compared atmospheric dry and wet deposition of N and P species in aerosol and rainwater in Singapore between haze and non haze periods. Air mass back trajectories showed that large-scale forest and peat fires in Sumatra and Kalimantan were a significant source of atmospheric nutrients to aquatic environments in Singapore and SEA region on hazy days. It was observed that the average concentrations of nutrients increased approximately by a factor of 3 to 8 on hazy days when compared with non-hazy days. The mean dry atmospheric fluxes (g/m2/year) of TN and TP observed during hazy and non-hazy days were 4.77±0.775 and 0.3±0.082, and 0.91±0.471 and 0.046±0.01, respectively. The mean wet deposition fluxes (g/m2/year) of TN and TP were 12.2±3.53 and 0.726±0.074, and 2.71±0.989 and 0.144±0.06 for hazy and non-hazy days, respectively. The occurrences of higher concentrations of nutrients from atmospheric deposition during smoke haze episodes may have adverse consequences on receiving aquatic ecosystems with cascading impacts on water quality.

  2. Impact of atmospheric convectively coupled equatorial Kelvin waves on upper ocean variability

    Science.gov (United States)

    Baranowski, Dariusz B.; Flatau, Maria K.; Flatau, Piotr J.; Matthews, Adrian J.

    2016-03-01

    Convectively coupled Kelvin waves (CCKWs) are atmospheric weather systems that propagate eastward along the equatorial wave guide with phase speeds between 11 and 14 m s-1. They are an important constituent of the convective envelope of the Madden-Julian oscillation (MJO), for which ocean-atmosphere interactions play a vital role. Hence, ocean-atmosphere interactions within CCKWs may be important for MJO development and prediction and for tropical climate, in general. Although the atmospheric structure of CCKWs has been well studied, their impact on the underlying ocean is unknown. In this paper, the ocean-atmosphere interactions in CCKWs are investigated by a case study from November 2011 during the CINDY/DYNAMO field experiment, using in situ oceanographic measurements from an ocean glider. The analysis is then extended to a 15 year period using precipitation data from the Tropical Rainfall Measuring Mission and surface fluxes from the TropFlux analysis. A methodology is developed to calculate trajectories of CCKWs. CCKW events are strongly controlled by the MJO, with twice as many CCKWs observed during the convectively active phase of the MJO compared to the suppressed phase. Coherent ocean-atmosphere interaction is observed during the passage of a CCKW, which lasts approximately 4 days at any given longitude. Surface wind speed and latent heat flux are enhanced, leading to a transient suppression of the diurnal cycle of sea surface temperature (SST) and a sustained decrease in bulk SST of 0.1°C. Given that a typical composite mean MJO SST anomaly is of the order of 0.3°C, and more than one CCKW can occur during the active phase of a single MJO event, the oceanographic impact of CCKWs is of major importance to the MJO cycle.

  3. Antioxidants, oxidants, and redox impacts on cell function - A tribute to Helmut Sies.

    Science.gov (United States)

    Cadenas, Enrique; Packer, Lester; Traber, Maret G

    2016-04-01

    This article is in tribute to Helmut Sies and is written by his friends from the Oxygen Club of California with personal recollections from each of us: Enrique Cadenas on "Oxidative Stress and Mentorship", Lester Packer on "The Antioxidant Network", and Maret G. Traber on "Nutrition and Chronic Disease". We conclude with a brief overview of the positive influence Helmut Sies has had on the Oxygen Club of California. PMID:27095223

  4. Impact of dehulling and germination on nutrients, antinutrients, and antioxidant properties in horsegram.

    Science.gov (United States)

    Pal, R S; Bhartiya, Anuradha; ArunKumar, R; Kant, Lakshmi; Aditya, J P; Bisht, J K

    2016-01-01

    The changes in chemical composition, antioxidant activity and minerals content of horse gram seed after dehulling and germination of 12 advance lines were investigated. Dehulled samples had a higher protein content compared with the raw and germinated. Total soluble sugars (TSS) content increased significantly (p ≤ 0.05) after dehulling (29.31 %) and germination (98.73 %) whereas, the total lipids increased (10.98 %) significantly (p ≤ 0.05) after dehulling and decreased (36.41 %) significantly (p ≤ 0.05) after germination. Dehulling and germination significantly decreased the amount of phytic acid (PA), tannin (TN) and oxalic acid (OA). Trypsin inhibitor units decreased (26.79 %) significantly (p ≤ 0.05) after germination. The minerals (Ca, Fe and Cu) composition of the germinated horsegram flour samples was significantly higher than the raw and dehulled flour. The functional properties of flours were studied and found that the bulk density (11.85 %) and oil absorption capacity (18.92 %) significantly increased after germination. Raw samples followed by germinated samples showed the highest concentrations of phytochemicals responsible for the antioxidant activity and also the antioxidant capacities. principal component analysis revealed that in case of dehulled samples; TN, polyphenols, DPPH and ABTS radical inhibition, TSS, total antioxidant, OA, protein, FRAP value, Ca and Zn had positive correlation among themselves while in case of germinated samples, protein, oil absorption capacity, FRAP value, OA, total flavonoids, DPPH radical inhibition, Ca and Cu had positive correlation among themselves. Present study suggest that germination combined with dehulling process improved quality of horsegram by enhancing the nutritive value and reducing the antinutrients. PMID:26787953

  5. Impact of atmospheric nitrogen deposition on phytoplankton productivity in the South China Sea

    Science.gov (United States)

    Kim, Tae-Wook; Lee, Kitack; Duce, Robert; Liss, Peter

    2014-05-01

    The impacts of anthropogenic nitrogen (N) deposition on the marine N cycle are only now being revealed, but the magnitudes of those impacts are largely unknown in time and space. The South China Sea (SCS) is particularly subject to high anthropogenic N deposition, because the adjacent countries are highly populated and have rapidly growing economies. Analysis of data sets for atmospheric N deposition, satellite chlorophyll-a (Chl-a), and air mass back trajectories reveals that the transport of N originating from the populated east coasts of China and Indonesia, and its deposition to the ocean, has been responsible for the enhancements of Chl-a in the SCS. We found that atmospheric N deposition contributed approximately 20% of the annual biological new production in the SCS. The airborne contribution of N to new production in the SCS is expected to grow considerably in the coming decades.

  6. Antioxidant effect of nondigestible levan and its impact on cardiovascular disease and atherosclerosis.

    Science.gov (United States)

    Dahech, Imen; Harrabi, Bahira; Hamden, Khaled; Feki, Abdelfattah; Mejdoub, Hafedh; Belghith, Hafedh; Belghith, Karima Srih

    2013-07-01

    Levan polysaccharide, a type of fructan, has been shown to favorably affect diabetes type 2 and hypercholesterolemia. Recent reports have indicated that excessive oxidative stress contributes to the development of atherosclerosis linked metabolic syndrome. The objective of this current study was to investigate the possible protection against oxidative stress linked atherosclerosis. A group of twenty four male rats was divided into four subgroups; a normal diet group (Control), normal rats received levan (L), a high-cholesterol diet group (Chol) and a high-cholesterol diet with 5% (w/w) levan group. After the treatment period, the plasma antioxidant enzymes and lipid profiles were determined. Our results show that treatment with levan positively changed plasma antioxidant enzyme activities by increasing superoxide dismutase (SOD) and catalase (CAT) by 40% and 28%, respectively, in heart. Similarly, the treatment of Chol fed groups with levan positively changed lipid profiles by decreasing total cholesterol, triglycerides and LDL-cholesterol by 50%, 38.33% and 64%, respectively. Thus may have potential antioxidant effects and could protect against oxidative stress linked atherosclerosis. PMID:23624165

  7. Impact of aerobic and anaerobic exercise training on oxidative stress and antioxidant defense in athletes.

    Science.gov (United States)

    Park, Song-Young; Kwak, Yi-Sub

    2016-04-01

    Exercise mediates an excessive free radical production leading to oxidative stress (OS). The body has natural antioxidant systems that help decrease OS, and these systems may be enhanced with exercise training. However, only a few studies have investigated the differences in resting OS and antioxidant capacity (AOC) between aerobically trained athletes (ET), anaerobically trained athletes (RT), and untrained individuals (UT). Therefore, this study sought to investigate the resting and postexercise OS and AOC in ET, RT, and UT. Sixty healthy young males (26.6±0.8 yr) participated in this study. Subjects were divided into three groups, ET, RT, and UT by distinct training background. Resting plasma malondialdehyde (MDA) and protein carbonyls (PC) were not significantly different in ET, RT, and UT. However, MDA and PC were significantly increased following a graded exercise test (GXT) in UT but not in ET and RT. Resting total antioxidant capacity (TAC) levels and TAC were not different in ET, RT, and UT. Interestingly, TAC levels significantly decreased after the GXT in all groups. Additionally, UT showed lower post-exercise TAC levels compared to ET and RT. These results showed that ET, RT, and UT have similar OS and AOC at rest. However, both ET and RT have greater AOC against exercise mediated OS compared to UT. These findings may explain, at least in part, why both aerobic and anaerobic types of exercise training improve redox balance. However, it appears there is no specific exercise type effect in terms of redox balance. PMID:27162773

  8. Impact of Elicitation on Antioxidant and Potential Antihypertensive Properties of Lentil Sprouts.

    Science.gov (United States)

    Peñas, Elena; Limón, Rocío I; Martínez-Villaluenga, Cristina; Restani, Patrizia; Pihlanto, Anne; Frias, Juana

    2015-12-01

    The aim of this study was to investigate the application of elicitors (500 μM ascorbic acid, 50 μM folic acid, 5 mM glutamic acid and 50 ppm chitosan in 5 mM glutamic acid) during lentil germination up to 8 days as a strategy to increase germination rate and to enhance the accumulation of γ-aminobutyric acid (GABA) and phenolic compounds. The effect of elicitation on the protein profile and antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities of sprouted lentils was also evaluated. The application of elicitors did not negatively affect the germination yield of lentils and no significant changes on the protein pattern of lentils germinated in the presence of elicitors were observed. Chitosan/glutamic acid increased by 1.6-fold the GABA content in lentil sprouts, whilst ascorbic and folic acids as well as chitosan/glutamic acid were highly effective to enhance the total content of phenolic compounds and the antioxidant activity of sprouted lentils. All elicited lentil sprouts showed ability to inhibit ACE activity (IC50: 9.5-11.9 μg peptides/mL). Therefore, elicitation can be considered a promising approach to improve the content of compounds with antioxidant and potential antihypertensive activities in lentil sprouts.

  9. Impact of Elicitation on Antioxidant and Potential Antihypertensive Properties of Lentil Sprouts.

    Science.gov (United States)

    Peñas, Elena; Limón, Rocío I; Martínez-Villaluenga, Cristina; Restani, Patrizia; Pihlanto, Anne; Frias, Juana

    2015-12-01

    The aim of this study was to investigate the application of elicitors (500 μM ascorbic acid, 50 μM folic acid, 5 mM glutamic acid and 50 ppm chitosan in 5 mM glutamic acid) during lentil germination up to 8 days as a strategy to increase germination rate and to enhance the accumulation of γ-aminobutyric acid (GABA) and phenolic compounds. The effect of elicitation on the protein profile and antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities of sprouted lentils was also evaluated. The application of elicitors did not negatively affect the germination yield of lentils and no significant changes on the protein pattern of lentils germinated in the presence of elicitors were observed. Chitosan/glutamic acid increased by 1.6-fold the GABA content in lentil sprouts, whilst ascorbic and folic acids as well as chitosan/glutamic acid were highly effective to enhance the total content of phenolic compounds and the antioxidant activity of sprouted lentils. All elicited lentil sprouts showed ability to inhibit ACE activity (IC50: 9.5-11.9 μg peptides/mL). Therefore, elicitation can be considered a promising approach to improve the content of compounds with antioxidant and potential antihypertensive activities in lentil sprouts. PMID:26433888

  10. Impact of aerobic and anaerobic exercise training on oxidative stress and antioxidant defense in athletes.

    Science.gov (United States)

    Park, Song-Young; Kwak, Yi-Sub

    2016-04-01

    Exercise mediates an excessive free radical production leading to oxidative stress (OS). The body has natural antioxidant systems that help decrease OS, and these systems may be enhanced with exercise training. However, only a few studies have investigated the differences in resting OS and antioxidant capacity (AOC) between aerobically trained athletes (ET), anaerobically trained athletes (RT), and untrained individuals (UT). Therefore, this study sought to investigate the resting and postexercise OS and AOC in ET, RT, and UT. Sixty healthy young males (26.6±0.8 yr) participated in this study. Subjects were divided into three groups, ET, RT, and UT by distinct training background. Resting plasma malondialdehyde (MDA) and protein carbonyls (PC) were not significantly different in ET, RT, and UT. However, MDA and PC were significantly increased following a graded exercise test (GXT) in UT but not in ET and RT. Resting total antioxidant capacity (TAC) levels and TAC were not different in ET, RT, and UT. Interestingly, TAC levels significantly decreased after the GXT in all groups. Additionally, UT showed lower post-exercise TAC levels compared to ET and RT. These results showed that ET, RT, and UT have similar OS and AOC at rest. However, both ET and RT have greater AOC against exercise mediated OS compared to UT. These findings may explain, at least in part, why both aerobic and anaerobic types of exercise training improve redox balance. However, it appears there is no specific exercise type effect in terms of redox balance.

  11. Spatial structure and scale feature of the atmospheric pollution source impact of city agglomeration

    Institute of Scientific and Technical Information of China (English)

    XU Xiangde; ZHOU Xiuji; SHI Xiaohui

    2005-01-01

    The spatial structure and multi-scale feature of the atmospheric pollution influence domain of Beijing and its peripheral areas (a rapidly developed city agglomeration) is dissected and analyzed in this paper on the basis of the atmospheric pollution dynamic-chemical process observation data of the urban building ensemble boundary layer of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter (February) and summer (August) 2003, and relevant meteorological elements and satellite retrieval aerosol optical depth (AOD), etc. comprehensive data with the dynamic-statistical integrated analysis of "point-surface" spatial structure. Results show that there existed significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution, and the principal component analysis (PCA) results of statistical model also indicate that SO2 and NOX dominated in the component structure of winter aerosol particle; instead, CO and NOX dominated in summer. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of building ensembles at urban different observational sites of Beijing in winter and summer showed an "in-phase" variation and its spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accorded with those of atmospheric wind field: the longer period was dominative in winter, but the shorter period in summer, revealing the impact of the seasonal scale feature of winter/summer atmospheric general circulation on the period of atmospheric pollution variations. It is found that from analyzing urban area thermal heterogeneity that the multiscale effect of Beijing region urban heat island (UHI) was associated with the heterogeneous expansion of tall buildings area. In urban atmospheric dynamical and thermal characteristic spatial structures, the

  12. The impact of atmospheric H2S on growth and sulfur metabolism of Allium cepa L.

    NARCIS (Netherlands)

    Durenkamp, M; De Kok, LJ

    2002-01-01

    The impact of atmospheric H2S deposition on growth and sulfur metabolism has been studied in onion (Allium cepa L.). The H2S Uptake followed saturation kinetics with respect to the H2S concentration. The maximum H2S uptake rate (JH(2)S(max)) was approx. 1 mumol g(-1) FW h(-1) and the KH2S (H2S conce

  13. Impact of the aerosol type on HICO™ atmospheric correction in coastal waters

    Directory of Open Access Journals (Sweden)

    C. Bassani

    2014-05-01

    Full Text Available The aim of this work is to evaluate the radiative impact of the aerosol type on the results of the atmospheric correction of HICO™ (Hyperspectral Imager for the Coastal Ocean hyperspectral data. The reflectance was obtained by using the HICO@CRI (HICO ATmospherically Corrected Reflectance Imagery algorithm, a physically-based atmospheric correction algorithm developed specifically for HICO™ data by adapting the vector version of the Second Simulation of a Satellite Signal in the Solar Spectrum (6SV radiative transfer code. The HICO@CRI algorithm was applied on six HICO™ images acquired in the Northern part of the Mediterranean Basin, using the micro-physical properties measured with a CIMEL sun sky-radiometer at the Acqua Alta Oceanographic Tower (AAOT AERONET site and the optical properties of the maritime, continental, and urban aerosol types provided by default by the 6SV. The results highlight that the aerosol type can improve the accuracy of the atmospheric correction. Indeed, the accuracy of the water reflectance retrieved from the available HICO™ data decreases in the sensor spectral domain, considering the AERONET micro-physical properties, of 30% using the urban aerosol type, of 20% using the continental type, and finally of less than 10% assuming a maritime type. Thus, the aerosol type has to be taken into consideration in the atmospheric correction of hyperspectral data over coastal environment, if water quality analysis has to be performed, because of the influence of aerosol type on the water reflectance.

  14. Simulation of the impact of thunderstorm activity on atmospheric gas composition

    Science.gov (United States)

    Smyshlyaev, S. P.; Mareev, E. A.; Galin, V. Ya.

    2010-08-01

    A chemistry-climate model of the lower and middle atmosphere has been used to estimate the sensitivity of the atmospheric gas composition to the rate of thunderstorm production of nitrogen oxides at upper tropospheric and lower stratospheric altitudes. The impact that nitrogen oxides produced by lightning have on the atmospheric gas composition is treated as a subgrid-scale process and included in the model parametrically. The natural uncertainty in the global production rate of nitrogen oxides in lightning flashes was specified within limits from 2 to 20 Tg N/year. Results of the model experiments have shown that, due to the variability of thunderstorm-produced nitrogen oxides, their concentration in the upper troposphere and lower stratosphere can vary by a factor of 2 or 3, which, given the influence of nitrogen oxides on ozone and other gases, creates the potential for a strong perturbation of the atmospheric gas composition and thermal regime. Model calculations have shown the strong sensitivity of ozone and the OH hydroxyl to the amount of lightning nitrogen oxides at different atmospheric altitudes. These calculations demonstrate the importance of nitrogen oxides of thunderstorm origin for the balance of atmospheric odd ozone and gases linked to it, such as ozone and hydroxyl radicals. Our results demonstrate that one important task is to raise the accuracy of estimates of the rate of nitrogen oxide production by lightning discharges and to use physical parametrizations that take into account the local lightning effects and feedbacks arising in this case rather than climatological data in models of the gas composition and general circulation of the atmosphere.

  15. Sea ice edge position impact on the atmospheric boundary layer temperature structure

    Science.gov (United States)

    Khavina, Elena; Repina, Irina

    2016-04-01

    temperature on heights from 0 to 1000 m. (time resolution 5 min., height resolution 50 m.). Results: 1) The structure of atmospheric temperature changes rapidly while the vessel is crossing the sea ice edge; 2) The impact of the underlying surface on the atmosphere above it was registered on the heights from 0 to 1000 meters; 3) The data on ice edge position obtained from the satellite and from the vessel varies greatly. Those discrepancies affect the further processing and analysis of data significantly and might cause the errors in models' development.

  16. Simulating the impacts of large scale insect- and disease-driven tree mortality on atmospheric chemistry

    Science.gov (United States)

    Geddes, J.; Heald, C. L.; Silva, S. J.; Martin, R.

    2015-12-01

    Land-use and land-cover change (LUC) is an important driver of global change through the alteration of local energy, moisture, and carbon exchanges. LUC can also directly impact the emission and deposition of important reactive trace gases, altering the oxidative chemistry of the atmosphere and subsequently air quality and climate. Large-scale tree mortality as a result of insects and disease may therefore have unexplored feedbacks on atmospheric chemistry. Between 2013 and 2027, over 80 million acres of treed land in the United States is predicted to experience basal area mortality rates exceeding 25%. We harmonized the description of land cover across the relevant surface-atmosphere exchange processes in the GEOS-Chem chemical transport model to facilitate LUC simulations, and used this adapted model to test the impact of projected tree mortality according to the 2012 USDA National Insect and Disease Risk Assessment. Nation-wide biogenic VOC emissions were reduced by 5%, with local impacts approaching 50% in some regions. By themselves, these emission reductions resulted in lower surface-level O3 mixing ratios, but this was counteracted by decreases in the O3 deposition velocity (by up to 10%) due to the reduction in vegetation density. Organic aerosol mass concentrations were also significantly affected across the United States, decreasing by 5-10% across the eastern U.S. and the northwest, with local impacts exceeding 25% in some regions. We discuss the general impacts on air quality in clean and polluted regions of the US, and point to developments needed for a more robust understanding of land cover change feedbacks.

  17. Antioxidant assays - consistent findings from FRAP and ORAC reveal a negative impact of organic cultivation on antioxidant potential in spinach but not watercress or rocket leaves.

    Science.gov (United States)

    Payne, Adrienne C; Mazzer, Alice; Clarkson, Graham J J; Taylor, Gail

    2013-11-01

    Watercress (Rorippa nasturtium-aquaticum), wild rocket (Diplotaxis tenuifolia), and spinach (Spinacia oleracea) are commercial crops reported to have high concentrations of antioxidants, possibly contributing to disease prevention following human consumption. Following analysis of supermarket-purchased salad leaves, we report the antioxidant content potential of these species using two comparable techniques assessing the consistency between the assays - by the ferric reducing antioxidant power (FRAP) assay and the oxygen radical absorbance capacity (ORAC) assay. The leaves were harvested from both conventionally and organically managed crops, to investigate whether organic agriculture results in improved crop quality. Watercress had the highest FRAP and ability to scavenge free radicals, followed by spinach and rocket. For watercress and rocket, there was no significant effect of organic agriculture on FRAP and ORAC, but for spinach, the antioxidant potential was reduced and this was significant at the 5% level of probability for FRAP but not ORAC, although the trend was clear in both tests. We conclude that there is variation in salad crop antioxidant potential and that FRAP and ORAC are useful techniques for measuring antioxidants in these salad crops with similar ranking for each salad crop studied.

  18. The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

    Directory of Open Access Journals (Sweden)

    J. C. McWilliams

    2008-03-01

    Full Text Available Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, integrated over 10 years, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production and export. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

  19. Impact features tracing hypervelocity airbursts on earth from the atmosphere to the ground

    Science.gov (United States)

    Courty, M. M.

    2012-12-01

    In the absence of deep craters, impact features have been debated to possibly tracing proximal ejecta from yet undetected structure or airburst debris from a meteorite collision with the terrestrial atmosphere or lithosphere. We examine the possibility for impact features to have originated from the shock layer formed ahead of a hypervelocity collider in the earth atmosphere. This hypothesis is approached by comparing impact features from controlled materials to puzzling geological ones: (1) debris collected at the ground from a high altitude meteor airburst recorded on 2011 August 2nd in Southern France; (2) laboratory experiments performed for defense purposes at the CEA Gramat Center (France) with the Persephone hypervelocity light gas gun; (3) the Zhamanshin impact breccia, the Lybian glass, the Egyptian Dakhleh glass, the Tasmanian Darwin glass, the Australasian tektite strewnfield and the Australian Henbury crater field. The Persephone experiments include collisions from 4.1 to 7.9 km/s by a steel projectile embedded into a polycarbonate holder with a polystyrene separator on to a 40 mm thick aluminum target. The impact features been characterized by coupling Environmental SEM with EDS, Raman micro-spectrometry, XRD, TEM, Tof-SIMS, ICP-MS and isotope analyses. Similar carbonaceous polymorphs that are closely imbricated at meso to nano-scales to the crystallized components (including the metal blebs) and to the glass phases (spherules or matrix) are present in all the impact features studied. They dominantly consist of aliphatic polymers, rare aromatic compounds, with graphite-lonsdaleite inclusions. The Persephone experiments help relating the graphite-lonsdaleite couple to transformed organic residues by the transient high pressure shock (a few tens MPa) and the transient heating (ca 100°C) and the aliphatic polymers to new hydrocarbons that formed from the pulverized polycarbonate and polystyrene. The Persephone experiments provide the controlled situation

  20. Future changes of the atmospheric composition and the impact of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Grewe, V.; Dameris, M.; Hein, R.; Sausen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Steil, B. [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany). Abt. Chemie der Atmosphaere

    1999-05-01

    The development of the future atmospheric chemical composition, with respect of NO{sub y} and O{sub 3} is investigated by means of the off-line coupled dynamic-chemical general circulation model ECHAM3/CHEM. Two time slice experiments have been performed for the years 1992 and 2015, which include changes in sea surface temperatures, greenhouse gas concentrations, emissions of CFCs, NO{sub x} and other species, i.e., the 2015 simulation accounts for changes in chemically relevant emissions and for a climate change and its impact on air chemistry. The 2015 simulation clearly shows a global increase in ozone except for large areas of the lower stratosphere, where no significant changes or even decreases in the ozone concentration are found. For a better understanding of the importance of (A) emissions like NO{sub x} and CFCs, (B) future changes of air temperature and water vapour concentration, and (C) other dynamic parameters, like precipitation and changes in the circulation, i.e. wind speed, diabatic circulation, stratosphere-troposphere-exchange, the simulation of the future atmosphere has been performed stepwise. This method requires a climate-chemistry model without interactive coupling of chemical species. Model results show that the direct effect of emissions (A) plays a major role for the composition of the future atmosphere, but they also clearly show that climate change has a significant impact and strongly reduces the NO{sub y} and ozone concentration in the lower stratosphere. (orig.)

  1. Impacts of changes in climate, land use and land cover on atmospheric mercury

    Science.gov (United States)

    Zhang, H.; Holmes, C. D.; Wu, S.

    2016-09-01

    Mercury is an important pollutant that can be transported globally due to its long lifetime in the atmosphere. Atmosphere-surface exchange is a major process affecting the cycling of mercury in the global environment and its impacts on food webs. We investigate the sensitivities of the air-surface exchange, atmospheric transport, and budget of mercury to projected 2000-2050 changes in climate and land use/land cover with a global chemical transport model (GEOS-Chem). We find that annual mean Hg(0) dry deposition flux over land could increase by up to 20% in northern mid-latitudes by 2050 due to increased vegetation and foliage density. Climate change can significantly affect both the wet deposition and atmospheric chemistry of mercury. In response to the projected climate change, the annual mean wet deposition flux increases over most continental regions and decreases over most of the mid-latitude and tropical oceans. The annual mean mercury wet deposition flux over northern and southern high latitudes increases by 7% and 8% respectively, largely driven by increases in precipitation there. Surface Hg(0) is predicted to increase generally, because high temperatures decrease Hg(0) oxidation by bromine and high moisture increases aqueous Hg(II) photo reduction. The combined effects of projected changes in climate, land use and land cover increase mercury deposition to the continental biosphere and decrease mercury deposition to the marine biosphere.

  2. NATO Advanced Study Institute on Pollutants from Combustion Formation and Impact on Atmospheric Chemistry

    CERN Document Server

    2000-01-01

    This volume is based on the lectures presented at the NATO Advanced Study Institute: (ASI) «Pollutants Formation from Combustion. Formation Mechanisms and Impact on th th Atmospheric Chemistry» held in Maratea, Italy, from 13 to 26 september 1998. Preservation of the environment is of increasing concern in individual countries but also at continental or world scales. The structure of a NATO ASI which involve lecturers and participants of different nationalities was thought as especially well suited to address environmental issues. As combustion is known to substantially contribute to the damaging of the atmosphere, it was natural to concentrate the ASI program on reviewing the currently available knowledge of the formation mechanisms of the main pollutants liberated by combustion systems. In most situations, pollutants are present as trace components and their formation and removal is strongly conditioned by the chemical reactions initiated by fuel consumption. Therefore specific lectures were aimed at defi...

  3. Impacts of SST and SST Anomalies on Low-Frequency Oscillation in the Tropical Atmosphere

    Institute of Scientific and Technical Information of China (English)

    HE Jinhai; YU Jingjing; SHEN Xinyong

    2007-01-01

    Considering the multiscale character of LFO (low-frequency oscillation) in the tropical atmosphere, the effects of SST on LFO in the tropical atmosphere are discussed by using an absolute ageostrophic, baroclinic model. Here, SST effects include sea surface heating and forcing of SST anomalies (SSTAs). Studies of the influences of sea surface heating on LFO frequency and stability show that sea surface heating can slow the speed of waves and lower their frequency when SST is comparatively low; while higher SST leads to unstable waves and less periods of LFO. Since the impact of a SSTA on ultra-long waves is more evident than that on kilometer-scale waves, long-wave approximation is used when we continue to study the effect of SSTAs. Results indicate that SSTAs can lead to a longer period of LFO, and make waves unstable. In other words,positive (negative) SSTAs can make waves decay (grow).

  4. The molecular composition of impact-generated atmospheres on terrestrial planets during the post-accretion stage

    Science.gov (United States)

    Kuwahara, Hideharu; Sugita, Seiji

    2015-09-01

    Both geochemical measurements and theoretical calculations suggest that impact degassing from meteoritic materials after the completion of main phase of planetary accretion may have produced a large fraction of the early terrestrial atmospheres. However, the molecular compositions of such impact-generated atmospheres are not well constrained because the thermodynamic cooling path, which controls the chemical reactions in impact-induced vapor, has not been investigated extensively. In this study, we theoretically assess the chemical reactions within impact-induced vapor that cools adiabatically until the pressure equilibrates with the ambient atmosphere. The calculation results indicate that there are two primary controlling factors for the cooling path: impact entropy gain and atmospheric pressure. The former is mainly determined by both impact velocity and the presence/absence of an ocean. The degree of atmospheric effect depends on vapor plume size. For large impacts, atmospheric containment of vapor expansion is inefficient. However, the expansion of small vapor plumes is contained by the pre-existing atmosphere and their terminal molecular composition is controlled by this process. This is because whether a chemical reaction quenches during adiabatic cooling or during subsequent radiative cooling would depend on the cooling transition temperature, at which adiabatic expansion stops and radiative cooling takes over. For high atmospheric pressures and/or the vapor generated by high-velocity impacts, adiabatic expansion will cease at higher temperatures than typical quenching temperatures. Thus, the molecular composition of the vapor will not greatly depend on the impact velocity. The calculation results suggest that the molecular composition of the impact-induced vapor would vary widely (i.e., CH4/CO ratios) even if the compositions of the impactors are the same. More specifically, the impact-induced vapor generated by lower velocity impacts may be rich in CH4

  5. Spatial structure and scale feature of the atmospheric pollution source impact of city agglomeration

    Institute of Scientific and Technical Information of China (English)

    XU; Xiangde; ZHOU; Xiuji; SHI; Xiaohui

    2005-01-01

    The spatial structure and multi-scale feature of the atmospheric pollution influence domain of Beijing and its peripheral areas (a rapidly developed city agglomeration) is dissected and analyzed in this paper on the basis of the atmospheric pollution dynamic-chemical process observation data of the urban building ensemble boundary layer of the Beijing City Air Pollution Observation Experiment (BECAPEX) in winter (February) and summer (August) 2003, and relevant meteorological elements and satellite retrieval aerosol optical depth (AOD), etc. comprehensive data with the dynamic-statistical integrated analysis of "point-surface" spatial structure. Results show that there existed significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution, and the principal component analysis (PCA) results of statistical model also indicate that SO2 and NOX dominated in the component structure of winter aerosol particle; instead, CO and NOX dominated in summer. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of building ensembles at urban different observational sites of Beijing in winter and summer showed an "in-phase" variation and its spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accorded with those of atmospheric wind field: the longer period was dominative in winter, but the shorter period in summer, revealing the impact of the seasonal scale feature of winter/summer atmospheric general circulation on the period of atmospheric pollution variations. It is found that from analyzing urban area thermal heterogeneity that the multiscale effect of Beijing region urban heat island (UHI) was associated with the heterogeneous expansion of tall buildings area. In urban atmospheric dynamical and thermal characteristic spatial structures, the

  6. Sanitary impact of the particulate atmospheric urban pollution; Impact sanitaire de la pollution atmospherique urbaine particulaire

    Energy Technology Data Exchange (ETDEWEB)

    Sentissi, M.

    1999-03-22

    The pollution of particulates origin is one of the principle actual problem relative to air quality. In France, the fine particulates come from industry and automobile traffic, especially, the diesel vehicles. The most worrying characteristic is their fineness, that allow them to stay in suspension during a long time and penetrate into pulmonary alveoli, with toxic elements at their surface such metals, acids, polycyclic aromatic hydrocarbons. The objective of this work is to take stock of epidemiology and toxicology studies evaluating the sanitary impact of particulates in suspension. (N.C.)

  7. Impact of biomass burning on ocean water quality in Southeast Asia through atmospheric deposition: field observations

    Science.gov (United States)

    Sundarambal, P.; Balasubramanian, R.; Tkalich, P.; He, J.

    2010-12-01

    Atmospheric nutrients have recently gained considerable attention as a significant additional source of new nitrogen (N) and phosphorus (P) loading to the ocean. The effect of atmospheric macro nutrients on marine productivity depends on the biological availability of both inorganic and organic N and P forms. During October 2006, the regional smoke haze episodes in Southeast Asia (SEA) that resulted from uncontrolled forest and peat fires in Sumatra and Borneo blanketed large parts of the region. In this work, we determined the chemical composition of nutrients in aerosols and rainwater during hazy and non-hazy days to assess their impacts on aquatic ecosystem in SEA for the first time. We compared atmospheric dry and wet deposition of N and P species in aerosol and rainwater in Singapore between hazy and non-hazy days. Air mass back trajectories showed that large-scale forest and peat fires in Sumatra and Kalimantan were a significant source of atmospheric nutrients to aquatic environments in Singapore and SEA region on hazy days. It was observed that the average concentrations of nutrients increased approximately by a factor of 3 to 8 on hazy days when compared with non-hazy days. The estimated mean dry and wet atmospheric fluxes (mg/m2/day) of total nitrogen (TN) were 12.72 ± 2.12 and 2.49 ± 1.29 during non-hazy days and 132.86 ± 38.39 and 29.43 ± 10.75 during hazy days; the uncertainty estimates are represented as 1 standard deviation (1σ) here and throughout the text. The estimated mean dry and wet deposition fluxes (mg/m2/day) of total phosphorous (TP) were 0.82 ± 0.23 and 0.13 ± 0.03 for non-hazy days and 7.89 ± 0.80 and 1.56 ± 0.65 for hazy days. The occurrences of higher concentrations of nutrients from atmospheric deposition during smoke haze episodes may have adverse consequences on receiving aquatic ecosystems with cascading impacts on water quality.

  8. Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate

    Directory of Open Access Journals (Sweden)

    C. E. Morris

    2011-01-01

    Full Text Available For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with proposals that the atmosphere is a global biome for microbial metabolic activity and perhaps even multiplication. As part of a series of papers on the sources, distribution and roles in atmospheric processes of biological particles in the atmosphere, here we describe the pertinence of questions relating to the potential roles that air-borne micro-organisms might play in meteorological phenomena. For the upcoming era of research on the role of air-borne micro-organisms in meteorological phenomena, one important challenge is to go beyond descriptions of abundance of micro-organisms in the atmosphere toward an understanding of their dynamics in terms of both biological and physico-chemical properties and of the relevant transport processes at different scales. Another challenge is to develop this understanding under contexts pertinent to their potential role in processes related to atmospheric chemistry, the formation of clouds, precipitation and radiative forcing. This will require truly interdisciplinary approaches involving collaborators from the biological and physical sciences, from disciplines as disparate as agronomy, microbial genetics and atmosphere physics, for example.

  9. Impact of MODIS SWIR band calibration improvements on Level-3 atmospheric products

    Science.gov (United States)

    Wald, Andrew; Levy, Robert C.; Angal, Amit; Geng, Xu; Xiong, Jack; Hoffman, Kurt

    2016-05-01

    The spectral reflectance measured by the MODIS reflective solar bands (RSB) is used for retrieving many atmospheric science products. The accuracy of these products depends on the accuracy of the calibration of the RSB. To this end, the RSB of the MODIS instruments are primarily calibrated on-orbit using regular solar diffuser (SD) observations. For λ earth-scene targets. This correction has been implemented in C6 for the Terra MODIS 1.24 μm band over the entire mission, and for the 1.38 μm band in the forward processing. As the instruments continue to operate beyond their design lifetime of six years, a similar correction is planned for other short-wave infrared (SWIR) bands as well. MODIS SWIR bands are used in deriving atmosphere products, including aerosol optical thickness, atmospheric total column water vapor, cloud fraction and cloud optical depth. The SD degradation correction in Terra bands 5 and 26 impact the spectral radiance and therefore the retrieval of these atmosphere products. Here, we describe the corrections to Bands 5 (1.24 μm) and 26 (1.38 μm), and produce three sets (B5, B26 correction = on/on, on/off, and off/off) of Terra-MODIS Level 1B (calibrated radiance product) data. By comparing products derived from these corrected and uncorrected Terra MODIS Level 1B (L1B) calibrations, dozens of L3 atmosphere products are surveyed for changes caused by the corrections, and representative results are presented. Aerosol and water vapor products show only small local changes, while some cloud products can change locally by >10%, which is a large change.

  10. Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

    Science.gov (United States)

    Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

    2015-12-15

    The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC

  11. Atmospheric Impact of Large Methane Emissions and the Gulf Oil Spill

    Science.gov (United States)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D. J.

    2010-12-01

    A vast quantity of a highly potent greenhouse gas, methane, is locked in the solid phase as methane clathrates in ocean sediments and underneath permafrost regions. Clathrates are ice-like deposits containing a mixture of water and gas (mostly methane) which are stable under high pressure and low temperatures. Current estimates are about 1600 - 2000 GtC present in oceans and about 400GtC in Arctic permafrost (Archer et al. 2009). This is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could rapidly destabilize the geothermal gradient which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could result in a number of effects including strong greenhouse heating, increased surface ozone, reduced stratospheric ozone, and intensification of the Arctic ozone hole. Many of the effects in the chemistry of the atmosphere are non-linear. In this paper, we present a parametric study of the effect of large scale methane release to the atmosphere. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with super-fast atmospheric chemistry module to simulate the response to increasing CH4 by 2, 3, 10 and 100 times that of the present day. We have also conducted a parametric study of the possible impact of gaseous emissions from the oil spill in the Gulf of Mexico, which is a proxy for future clathrate releases. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

    Science.gov (United States)

    Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

    2015-12-15

    The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC

  13. Addressing model error through atmospheric stochastic physical parametrizations: impact on the coupled ECMWF seasonal forecasting system.

    Science.gov (United States)

    Weisheimer, Antje; Corti, Susanna; Palmer, Tim; Vitart, Frederic

    2014-06-28

    The finite resolution of general circulation models of the coupled atmosphere-ocean system and the effects of sub-grid-scale variability present a major source of uncertainty in model simulations on all time scales. The European Centre for Medium-Range Weather Forecasts has been at the forefront of developing new approaches to account for these uncertainties. In particular, the stochastically perturbed physical tendency scheme and the stochastically perturbed backscatter algorithm for the atmosphere are now used routinely for global numerical weather prediction. The European Centre also performs long-range predictions of the coupled atmosphere-ocean climate system in operational forecast mode, and the latest seasonal forecasting system--System 4--has the stochastically perturbed tendency and backscatter schemes implemented in a similar way to that for the medium-range weather forecasts. Here, we present results of the impact of these schemes in System 4 by contrasting the operational performance on seasonal time scales during the retrospective forecast period 1981-2010 with comparable simulations that do not account for the representation of model uncertainty. We find that the stochastic tendency perturbation schemes helped to reduce excessively strong convective activity especially over the Maritime Continent and the tropical Western Pacific, leading to reduced biases of the outgoing longwave radiation (OLR), cloud cover, precipitation and near-surface winds. Positive impact was also found for the statistics of the Madden-Julian oscillation (MJO), showing an increase in the frequencies and amplitudes of MJO events. Further, the errors of El Niño southern oscillation forecasts become smaller, whereas increases in ensemble spread lead to a better calibrated system if the stochastic tendency is activated. The backscatter scheme has overall neutral impact. Finally, evidence for noise-activated regime transitions has been found in a cluster analysis of mid

  14. Process analysis of the modelled 3-D mesoscale impact of aircraft emissions on the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, J.; Ebel, A.; Lippert, E.; Petry, H. [Koeln Univ. (Germany). Inst. fuer Geophysik und Meterorologie

    1997-12-31

    A mesoscale chemistry transport model is applied to study the impact of aircraft emissions on the atmospheric trace gas composition. A special analysis of the simulations is conducted to separate the effects of chemistry, transport, diffusion and cloud processes on the transformation of the exhausts of a subsonic fleet cruising over the North Atlantic. The aircraft induced ozone production strongly depends on the tropopause height and the cruise altitude. Aircraft emissions may undergo an effective downward transport under the influence of stratosphere-troposphere exchange activity. (author) 12 refs.

  15. Antioxidant and antimicrobial effects of dietary supplementation with rosemary diterpenes (carnosic acid and carnosol) vs vitamin E on lamb meat packed under protective atmosphere.

    Science.gov (United States)

    Ortuño, Jordi; Serrano, Rafael; Bañón, Sancho

    2015-12-01

    The antioxidant and antimicrobial effects on lamb meat of the dietary use of rosemary diterpenes and vitamin E were compared. Thirty fattening lambs were assigned to three diets: (C) control; (R) C plus 600 mg kg(-1) carnosic acid and carnosol at 1:1 w:w; or (E) C plus 600 mg kg(-1) α-tocopherol. The deposition of the dietary supplements in the muscle was determined. Microbial quality (total viable counts, Lactic Acid Bacteria, Enterobacteriaceae, Escherichia coli and Salmonella spp), oxidative stability (CIELab color, malondialdehyde and total carbonyls) and sensory attributes (appearance and odor) were determined in loin stored at 2°C under 70% O2/30% CO2 atmosphere. Microbial quality was ensured by packaging and chilling. The E-diet was more effective (P ≤ 0.05) than the R-diet in preventing meat oxidation, although the latter had antimicrobial effects on meat. The shelf life of lamb (assessed as the loss of freshness) could be increased by 5 (R-diet) or 10 (E-diet) days.

  16. Antioxidant and antimicrobial effects of dietary supplementation with rosemary diterpenes (carnosic acid and carnosol) vs vitamin E on lamb meat packed under protective atmosphere.

    Science.gov (United States)

    Ortuño, Jordi; Serrano, Rafael; Bañón, Sancho

    2015-12-01

    The antioxidant and antimicrobial effects on lamb meat of the dietary use of rosemary diterpenes and vitamin E were compared. Thirty fattening lambs were assigned to three diets: (C) control; (R) C plus 600 mg kg(-1) carnosic acid and carnosol at 1:1 w:w; or (E) C plus 600 mg kg(-1) α-tocopherol. The deposition of the dietary supplements in the muscle was determined. Microbial quality (total viable counts, Lactic Acid Bacteria, Enterobacteriaceae, Escherichia coli and Salmonella spp), oxidative stability (CIELab color, malondialdehyde and total carbonyls) and sensory attributes (appearance and odor) were determined in loin stored at 2°C under 70% O2/30% CO2 atmosphere. Microbial quality was ensured by packaging and chilling. The E-diet was more effective (P ≤ 0.05) than the R-diet in preventing meat oxidation, although the latter had antimicrobial effects on meat. The shelf life of lamb (assessed as the loss of freshness) could be increased by 5 (R-diet) or 10 (E-diet) days. PMID:26186399

  17. 10-year record of atmospheric composition in the high Himalayas: source, transport and impact

    Science.gov (United States)

    Bonasoni, Paolo; Laj, Paolo; Marinoni, Angela; Cristofanelli, Paolo; Maione, Michela; Putero, Davide; Calzolari, Francescopiero; Decesari, Stefano; Facchini, Maria Cristina; Fuzzi, Sandro; Gobbi, Gianpaolo; Sellegri, Karine; Verza, Gianpietro; Vuillermoz, Elisa; Arduini, Jgor

    2016-04-01

    South Asia represents a global "hot-spot" for air-quality and climate impacts. Since the end of the 20th Century, field experiments and satellite observations identified a thick layer of atmospheric pollutants extending from the Indian Ocean up to the atmosphere of the Himalayas. Since large amount of short-lived climate pollutants (SLCPs) - like atmospheric aerosol (in particular, the light-absorbing aerosol) and ozone - characterize this region, severe implications were recognized for population health, ecosystem integrity as well as regional climate impacts, especially for what concerns hydrological cycle, monsoon regimes and cryosphere. Since 2006, the Nepal Climate Observatory - Pyramid (NCO-P, 27.95N, 86.82 E, 5079 m a.s.l.), a global station of the WMO/GAW programme has been active in the eastern Nepal Himalaya, not far from the Mt. Everest. NCO-P is located away from large direct anthropogenic pollution sources. The closest major urban area is Kathmandu (200 km south-west from the measurement site). As being located along the Khumbu valley, the observations are representative of synoptic-scale and mountain thermal circulation, providing direct information about the vertical transport of pollutants/climate-altering compounds to the Himalayas and to the free troposphere. In the framework of international programmes (GAW/WMO, UNEP-ABC, AERONET) the following continuous measurement programmes have been carried out at NCO-P: surface ozone, aerosol size distribution (from 10 nm to 25 micron), total particle number, aerosol scattering and absorption coefficients, equivalent BC, PM1-PM10, AOD by sun-photometry, global solar radiation (SW and LW), meteorology. Long-term sampling programmes for the off-line determination of halogenated gases and aerosol chemistry have been also activated. The atmospheric observation records at NCO-P, now representing the longest time series available for the high Himalayas, provided the first direct evidences about the systematic

  18. Research and application on the technology system of multiscale assessment of the impact on the atmospheric environment by urban planning

    Institute of Scientific and Technical Information of China (English)

    WANG Guangtao; WANG Xiaoyun; MIAO Shiguang; JIANG Weimei; GUO Wenli; JI Chongping; CHEN Xianyan

    2005-01-01

    Improvement of the atmospheric environment in urban planning is an important issue to implement the sustainable development of cities. In this paper, in order to meet the demand of planning office to compare and assess quantitatively of the designs in multi-scale, based on geographical information system (GIS) data with high resolution, a multi-scale numerical modeling system for the atmospheric environment impact of urban planning is set up, and the multi-scale assessment index system is established, which compose the technology system of multi-scale assessment of the impact on the atmospheric environment by urban planning. In urban planning (urban development of Beijing) and optimizing layouts of Olympic Green, it has been applied to quantitatively evaluating the impact on atmospheric environment by urban planning before construction, which offers scientific foundation to optimize the whole and local urban layout.

  19. Impact of MODIS SWIR band calibration improvements on Level-3 atmospheric products

    Science.gov (United States)

    Wald, Andrew; Levy, Robert C.; Angal, Amit; Geng, Xu; Xiong, Jack; Hoffman, Kurt

    2016-05-01

    The spectral reflectance measured by the MODIS reflective solar bands (RSB) is used for retrieving many atmospheric science products. The accuracy of these products depends on the accuracy of the calibration of the RSB. To this end, the RSB of the MODIS instruments are primarily calibrated on-orbit using regular solar diffuser (SD) observations. For λ vapor, cloud fraction and cloud optical depth. The SD degradation correction in Terra bands 5 and 26 impact the spectral radiance and therefore the retrieval of these atmosphere products. Here, we describe the corrections to Bands 5 (1.24 μm) and 26 (1.38 μm), and produce three sets (B5, B26 correction = on/on, on/off, and off/off) of Terra-MODIS Level 1B (calibrated radiance product) data. By comparing products derived from these corrected and uncorrected Terra MODIS Level 1B (L1B) calibrations, dozens of L3 atmosphere products are surveyed for changes caused by the corrections, and representative results are presented. Aerosol and water vapor products show only small local changes, while some cloud products can change locally by >10%, which is a large change.

  20. On the Impact of Wind Farms on a Convective Atmospheric Boundary Layer

    Science.gov (United States)

    Lu, Hao; Porté-Agel, Fernando

    2015-10-01

    With the rapid growth in the number of wind turbines installed worldwide, a demand exists for a clear understanding of how wind farms modify land-atmosphere exchanges. Here, we conduct three-dimensional large-eddy simulations to investigate the impact of wind farms on a convective atmospheric boundary layer. Surface temperature and heat flux are determined using a surface thermal energy balance approach, coupled with the solution of a three-dimensional heat equation in the soil. We study several cases of aligned and staggered wind farms with different streamwise and spanwise spacings. The farms consist of Siemens SWT-2.3-93 wind turbines. Results reveal that, in the presence of wind turbines, the stability of the atmospheric boundary layer is modified, the boundary-layer height is increased, and the magnitude of the surface heat flux is slightly reduced. Results also show an increase in land-surface temperature, a slight reduction in the vertically-integrated temperature, and a heterogeneous spatial distribution of the surface heat flux.

  1. The impact of atmospheric deposition of cadmium on dominant algal species in the East China Sea

    Science.gov (United States)

    Quan, Qiwei; Chen, Ying; Ma, Qingwei; Wang, Fujiang; Meng, Xi; Wang, Bo

    2016-04-01

    Cadmium (Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem, affecting the phytoplankton community and primary productivity. In this study, we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea (ECS) through both laboratory and in situ mesocosm incubation experiments. The mesocosm experiment showed that Cd in low concentration (0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity. In high concentration (0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity. The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate, as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth. We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region. In our laboratory experiments, adding Cd, similar to aerosol deposition, stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu (dinoflagellate) and Skeletonema costatum (diatom). Adding Cd on a higher level inhibited the growth of both the species, but Skeletonema costatum seemed obviously more sensitive to toxicity. This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS.

  2. Fukushima Daiichi Nuclear Plant accident: Atmospheric and oceanic impacts over the five years.

    Science.gov (United States)

    Hirose, Katsumi

    2016-06-01

    The Fukushima Daiichi Nuclear Plant (FDNPP) accident resulted in huge environmental and socioeconomic impacts to Japan. To document the actual environmental and socioeconomic effects of the FDNPP accident, we describe here atmospheric and marine contamination due to radionuclides released from the FDNPP accident using papers published during past five years, in which temporal and spatial variations of FDNPP-derived radionuclides in air, deposition and seawater and their mapping are recorded by local, regional and global monitoring activities. High radioactivity-contaminated area in land were formed by the dispersion of the radioactive cloud and precipitation, depending on land topography and local meteorological conditions, whereas extremely high concentrations of (131)I and radiocesium in seawater occurred due to direct release of radioactivity-contaminated stagnant water in addition to atmospheric deposition. For both of atmosphere and ocean, numerical model simulations, including local, regional and global-scale modeling, were extensively employed to evaluate source terms of the FDNPP-derived radionuclides from the monitoring data. These models also provided predictions of the dispersion and high deposition areas of the FDNPP-derived radionuclides. However, there are significant differences between the observed and simulated values. Then, the monitoring data would give a good opportunity to improve numerical modeling. PMID:27032342

  3. Impact of atmospheric wet deposition on phytoplankton community structure in the South China Sea

    Science.gov (United States)

    Cui, Dong-Yang; Wang, Jiang-Tao; Tan, Li-Ju; Dong, Ze-Yi

    2016-05-01

    The South China Sea (SCS), which is the largest marginal sea in East Asia, plays a significant role in regional climate change. However, research on the phytoplankton community structure (PCS) response to atmospheric wet deposition remains inadequate. In this study, field incubation experiments were performed to survey the impact of atmospheric wet deposition on the PCS in the SCS in December 2013. Results indicate that the mean dissolved inorganic nitrogen/dissolved inorganic phosphorous (DIN/DIP) ratio in rainwater was 136, which was higher than that in seawater. Under low initial nutrient concentrations, rainwater inputs not only significantly increased total chlorophyll a (Chl a) concentrations but also potentially altered the PCS. The total Chl a concentration increased 1.7-, 1.9-, and 1.6-fold; microphytoplankton increased 2.6-, 3.2-, and 1.7-fold with respect to their initial values in the 5%, 10% addition, and 10% addition (filtered) treatment samples, respectively. Finally, microphytoplankton contributed 61% to the total Chl a concentration in 10% addition treatment samples. Differences in the nutrients induced by atmospheric wet deposition resulted in a shift in the advantage from picophytoplankton to microphytoplankton. Diatoms became the predominant species, accounting for 55% of the total abundance after rainwater addition.

  4. Impact of atmospheric release in stable night meteorological conditions; can emergency models predict dispersion

    International Nuclear Information System (INIS)

    Atmospheric dispersion of pollutant or radionuclides in stratified meteorological condition, i.e. especially when weather conditions are very stable, mainly at night, is still poorly understood and not well apprehended by the operational atmospheric dispersion models. However, correctly predicting the dispersion of a radioactive plume, and estimating the radiological consequences for the population, following an unplanned atmospheric release of radionuclides are crucial steps in an emergency response. To better understand dispersion in these special weather conditions, IRSN performed a series of 22 air sampling campaigns between 2010 and 2013 in the vicinity of the La Hague nuclear reprocessing plant (AREVA - NC, France), at distances between 200 m and 3000 m from the facility. Krypton-85 (85Kr), a b-and g-emitting radionuclide, released during the reprocessing of spent nuclear fuel was used as a non-reactive tracer of radioactive plumes. Experimental campaigns were realized in stability class stable or very stable (E or F according to Pasquill classification) 18 times, and in neutral conditions (D according to Pasquill classification) 4 times. During each campaign, Krypton-85 real time measurement were made to find the plume around the plant, and then integrated samples (30 min) were collected in bag perpendicularly to the assumed wind direction axis. After measurement by gamma spectrometry, we have, when it was possible, estimate the point of impact and the width of the plume. The objective was to estimate the horizontal dispersion (width) of the plume at ground level in function of the distance and be able to calculate atmospheric transfer coefficients. In a second step, objective was to conclude on the use of common model and on their uncertainties. The results will be presented in terms of impact on the near-field. They will be compared with data obtained in previous years in neutral atmospheric conditions, and finally the results will be confronted with those

  5. Impact of atmospheric release in stable night meteorological conditions; can emergency models predict dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Connan, O.; Hebert, D.; Solier, L.; Voiseux, C.; Lamotte, M.; Laguionie, P.; Maro, D.; Thomas, L. [IRSN/PRP-ENV/SERIS/LRC (France)

    2014-07-01

    Atmospheric dispersion of pollutant or radionuclides in stratified meteorological condition, i.e. especially when weather conditions are very stable, mainly at night, is still poorly understood and not well apprehended by the operational atmospheric dispersion models. However, correctly predicting the dispersion of a radioactive plume, and estimating the radiological consequences for the population, following an unplanned atmospheric release of radionuclides are crucial steps in an emergency response. To better understand dispersion in these special weather conditions, IRSN performed a series of 22 air sampling campaigns between 2010 and 2013 in the vicinity of the La Hague nuclear reprocessing plant (AREVA - NC, France), at distances between 200 m and 3000 m from the facility. Krypton-85 ({sup 85}Kr), a b-and g-emitting radionuclide, released during the reprocessing of spent nuclear fuel was used as a non-reactive tracer of radioactive plumes. Experimental campaigns were realized in stability class stable or very stable (E or F according to Pasquill classification) 18 times, and in neutral conditions (D according to Pasquill classification) 4 times. During each campaign, Krypton-85 real time measurement were made to find the plume around the plant, and then integrated samples (30 min) were collected in bag perpendicularly to the assumed wind direction axis. After measurement by gamma spectrometry, we have, when it was possible, estimate the point of impact and the width of the plume. The objective was to estimate the horizontal dispersion (width) of the plume at ground level in function of the distance and be able to calculate atmospheric transfer coefficients. In a second step, objective was to conclude on the use of common model and on their uncertainties. The results will be presented in terms of impact on the near-field. They will be compared with data obtained in previous years in neutral atmospheric conditions, and finally the results will be confronted with

  6. Antioxidant properties of caroot juices and their impact on intestinal and probiotic bacteria

    OpenAIRE

    Aleksandra Duda-Chodak; Tomasz Tarko; Łukasz Wajda; Bożena Kręcioch

    2015-01-01

    There is a growing interest in non-dairy probiotic products. The main aim of the study was to evaluate the impact of juice prepared from 15 various cultivars of carrot on the growth of representatives of human intestinal microbiota (Bifidobacterium catenulatum, Escherichia coli) and probiotic strains (Lactobacillus acidophilus LA-5, Lactobacillus casei 01). Carrot juice was added to liquid medium at a final concentration of 5.0% and their impact on the bacteria number was assess...

  7. Impact of urban atmospheric environment on hospital admissions in the elderly

    Directory of Open Access Journals (Sweden)

    Edelci Nunes da Silva

    2012-08-01

    Full Text Available OBJECTIVE: To analyze the impact of intra-urban atmospheric conditions on circulatory and respiratory diseases in elder adults. METHODS: Cross-sectional study based on data from 33,212 hospital admissions in adults over 60 years in the city of São Paulo, southeastern Brazil, from 2003 to 2007. The association between atmospheric variables from Congonhas airport and bioclimatic index, Physiological Equivalent Temperature, was analyzed according to the district's socioenvironmental profile. Descriptive statistical analysis and regression models were used. RESULTS: There was an increase in hospital admissions due to circulatory diseases as average and lowest temperatures decreased. The likelihood of being admitted to the hospital increased by 12% with 1ºC decrease in the bioclimatic index and with 1ºC increase in the highest temperatures in the group with lower socioenvironmental conditions. The risk of admission due to respiratory diseases increased with inadequate air quality in districts with higher socioenvironmental conditions. CONCLUSIONS: The associations between morbidity and climate variables and the comfort index varied in different groups and diseases. Lower and higher temperatures increased the risk of hospital admission in the elderly. Districts with lower socioenvironmental conditions showed greater adverse health impacts.

  8. Impact of Ion Implantation on Licorice (Glycyrrhiza uralensis Fisch) Growth and Antioxidant Activity Under Drought Stress

    International Nuclear Information System (INIS)

    Low energy ion beams are known to have stimulation effects on plant generation and to improve plants' intrinsic quality. In the present study, the growth and physiological index of licorice implanted with 0, 8, 10, 12 and 14x (2.6x1015) ions/cm2 were investigated under well-watered and drought-stress conditions. The results showed that a proper dose of ion implantation was particularly efficient in stimulating the licorice growth and improving the plant biomass significantly in both the well-watered and drought-stress conditions. The physiological results of licorice measured by leaf water potential, lipid oxidation, soluble protein and antioxidant system showed a significant correlation between ion implantation and water regime except for leaf water potential. Therefore, the study indicated that ion implantation can enhance licorice's drought tolerance by increasing the activity of superoxide dismutase (SOD), catalase (CAT) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability to lower oxidative damage to lipids in plants. Ion beam implantation, therefore, provides an alternative method to enhance licorice drought tolerance

  9. Impact of blanching on polyphenol stability and antioxidant capacity of innovative coriander (Coriandrum sativum L.) pastes.

    Science.gov (United States)

    Kaiser, Andrea; Kammerer, Dietmar R; Carle, Reinhold

    2013-09-01

    Fresh coriander leaves were steam- and water-blanched at 100 °C and at 90 and 100 °C, respectively, for 1-10 min, and subsequently comminuted to form a paste. Pasty products obtained from coriander fruits were processed after water-blanching applying the same time-temperature regimes. Among the 11 phenolics characterised in leaves by high-performance liquid chromatography coupled to mass spectrometric detection, several caffeic acid derivatives, 5-feruloylquinic and 5-p-coumaroylquinic acids were tentatively identified for the first time. In fruits, 10 phenolics were detected, whereas rutin, a dicaffeic acid derivative and two feruloylquinic and caffeoylquinic acid isomers were newly detected. Upon steam-blanching for 1 min, phenolic contents and antioxidant capacities remained virtually unchanged. In contrast, water-blanching and extended steam-blanching even yielded increased levels compared to the unheated control, whereas short-time water-blanching resulted in higher values than prolonged heat treatment. Thus, short-time water-blanching is recommended as the initial unit in the processing of coriander leaves and fruits into novel pasty products.

  10. Impact of Ion Implantation on Licorice ( Glycyrrhiza uralensis Fisch ) Growth and Antioxidant Activity Under Drought Stress

    Institute of Scientific and Technical Information of China (English)

    LIU Jingnan; TONG Liping; SHEN Tongwei; LI Jie; WU Lijun; YU Zengliang

    2007-01-01

    Low energy ion beams are known to have stimulation effects on plant generation and to improve plants' intrinsic quality. In the present study, the growth and physiological index of licorice implanted with 0, 8, 10, 12 and 14× (2.6×l015) ions/cm2 were investigated under well-watered and drought-stress conditions. The results showed that a proper dose of ion implantation was particularly efficient in stimulating the licorice growth and improving the plant biomass significantly in both the well-watered and drought-stress conditions. The physiological results of licorice measured by leaf water potential, lipid oxidation, soluble protein and antioxidant system showed a significant correlation between ion implantation and water regime except for leaf water potential. Therefore, the study indicated that ion implantation can enhance licorice's drought tolerance by increasing the activity of superoxide dismutase (SOD), catalase (CAT) and DPPH (l,l-diphenyl-2-picrylhydrazyl) radical scavenging ability to lower oxidative damage to lipids in plants. Ion beam implantation, therefore, provides an alternative method to enhance licorice drought tolerance.

  11. Impact of Ion Implantation on Licorice (Glycyrrhiza uralensis Fisch) Growth and Antioxidant Activity Under Drought Stress

    Science.gov (United States)

    Liu, Jingnan; Tong, Liping; Shen, Tongwei; Li, Jie; Wu, Lijun; Yu, Zengliang

    2007-06-01

    Low energy ion beams are known to have stimulation effects on plant generation and to improve plants' intrinsic quality. In the present study, the growth and physiological index of licorice implanted with 0, 8, 10, 12 and 14× (2.6×1015) ions/cm2 were investigated under well-watered and drought-stress conditions. The results showed that a proper dose of ion implantation was particularly efficient in stimulating the licorice growth and improving the plant biomass significantly in both the well-watered and drought-stress conditions. The physiological results of licorice measured by leaf water potential, lipid oxidation, soluble protein and antioxidant system showed a significant correlation between ion implantation and water regime except for leaf water potential. Therefore, the study indicated that ion implantation can enhance licorice's drought tolerance by increasing the activity of superoxide dismutase (SOD), catalase (CAT) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability to lower oxidative damage to lipids in plants. Ion beam implantation, therefore, provides an alternative method to enhance licorice drought tolerance.

  12. Cross Sections for Electron Impact Excitation of Ions Relevant to Planetary Atmospheres Observation

    Science.gov (United States)

    Tayal, Swaraj S.

    1998-01-01

    The goal of this research grant was to calculate accurate oscillator strengths and electron collisional excitation strengths for inelastic transitions in atomic species of relevance to Planetary Atmospheres. Large scale configuration-interaction atomic structure calculations have been performed to obtain oscillator strengths and transition probabilities for transitions among the fine-structure levels and R-matrix method has been used in the calculations of electron-ion collision cross sections of C II, S I, S II, S III, and Ar II. A number of strong features due to ions of sulfur have been detected in the spectra of Jupiter satellite Io. The electron excitation cross sections for the C II and S II transitions are studied in collaboration with the experimental atomic physics group at the Jet Propulsion Laboratory. There is excellent agreement between experiment and theory which provide an accurate and broad-base test of the ability of theoretical methods used in the calculation of atomic processes. Specifically, research problems have been investigated for: electron impact excitation cross sections of C II: electron impact excitation cross sections of S III; energy levels and oscillator strengths for transitions in S III; collision strengths for electron collisional excitation of S II; electron impact excitation of inelastic transitions in Ar II; oscillator strengths of fine-structure transitions in neutral sulfur; cross sections for inelastic scattering of electrons from atomic nitrogen; and excitation of atomic ions by electron impact.

  13. Atmospheric outflow of Nutrients to the Bay of Bengal: Impact of continental sources

    Science.gov (United States)

    Sarin, Manmohan; Srinivas, Bikkina

    2014-05-01

    The air-sea deposition of nutrients (N, P and Fe) to the oceanic regions located downwind of pollution sources in south Asia is gaining considerable attention in the present-day scenario of climate change. We report here a case study on the abundances of nutrients, their sources and temporal variability in the atmospheric outflow from the Indo-Gangetic Plain (IGP) to the Bay of Bengal (BoB). Air mass back trajectory analysis suggests conspicuous downwind transport of chemical constituents from the IGP to BoB during the late NE-monsoon (January-April). During rest of the year, wind-regimes do not favour the atmospheric transport from the IGP, making BoB a unique oceanic region in the global perspective. Concentrations of NO3-, NH4+, NOrg, PO43- and Fews in the atmospheric outflow from the IGP, studied during November'09 - March'10, show pronounced temporal variability. The inorganic nitrogen dominates (NH4+-N: ~ 90 % of NInorg) the total soluble nitrogen (NTot). Although the contribution of organic nitrogen is not significant, the mass ratio of NOrg/NTot in the outflow varied from 0.07 to 0.40. The abundances of PInorg and Fews varied from 0.4 to 4.8 nmol m-3 and 0.2 to 0.6 nmol m-3, respectively. The high abundance of K+and significant (P-value iron (FeTot: 60-1144 ng m-3), its fractional solubility (Fews %: 6.7 -26.5) and co-variability of Fews (%) with nss-SO42- suggests chemical processing of alluvial dust during atmospheric transport from the IGP. The characteristic mass ratios of nutrients (NInorg/NTot: 0.92 ± 0.13, NOrg/NTot: 0.21 ± 0.11, and PInorg/nss-Ca2+: 0.35 ± 0.23) in the atmospheric outflow from the IGP show striking similarity with those reported over the BoB. These results have implications to further increase in the atmospheric deposition of nutrients and their impact on biogeochemistry of surface Bay of Bengal.

  14. Impact of atmospheric refraction: how deeply can we probe exo-earth's atmospheres during primary eclipse observations?

    Energy Technology Data Exchange (ETDEWEB)

    Bétrémieux, Yan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Kaltenegger, Lisa, E-mail: betremieux@mpia.de [Also at Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. (United States)

    2014-08-10

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density and pressure, probed during primary eclipses as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction for all exoplanets and tabulate the critical altitude, density, and pressure for an exoplanet identical to Earth with a 1 bar N{sub 2}/O{sub 2} atmosphere as a function of both the incident stellar flux (Venus, Earth, and Mars-like) at the top of the atmosphere and the spectral type (O5-M9) of the host star. We show that such a habitable exo-Earth can be probed to a surface pressure of 1 bar only around the coolest stars. We present 0.4-5.0 μm model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

  15. Impact of Atmospheric Microparticles on the Development of Oxidative Stress in Healthy City/Industrial Seaport Residents

    Directory of Open Access Journals (Sweden)

    Kirill Golokhvast

    2015-01-01

    Full Text Available Atmospheric microsized particles producing reactive oxygen species can pose a serious health risk for city residents. We studied the responses of organisms to microparticles in 255 healthy volunteers living in areas with different levels of microparticle air pollution. We analyzed the distribution of microparticles in snow samples by size and content. ELISA and flow cytometry methods were employed to determine the parameters of the thiol-disulfide metabolism, peroxidation and antioxidant, genotoxicity, and energy state of the leukocytes. We found that, in the park areas, microparticles with a size of 800 μm or more were predominant (96%, while in the industrial areas, they tended to be less than 50 μm (93%, including size 200–300 nm (7%. In the industrial areas, we determined the oxidative modification of proteins (21% compared to the park areas, p≤0.05 and DNA (12%, p≤0.05, as well as changes in leukocytes’ energy potential (53%, p≤0.05. An increase in total antioxidant activity (82%, p≤0.01 and thiol-disulfide system response (thioredoxin increasing by 33%, p≤0.01; glutathione, 30%, p≤0.01 with stable reductases levels maintains a balance of peroxidation-antioxidant processes, protecting cellular and subcellular structures from significant oxidative damage.

  16. Impact of atmospheric refraction: How deeply can we probe exo-Earth's atmospheres during primary eclipse observations?

    CERN Document Server

    Betremieux, Y

    2013-01-01

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density, probed during primary eclipses, as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction and show that most habitable exo-Earths cannot be probed down to their surface. We present 0.4-5.0micron model transmission spectra of Earth's atmosphere viewed as a transiting exoplanet, and show how atmospheric refraction modifies the transmission spectrum depending on the spectral type (O5-M9) of the host star. We demonstrate that refraction is another phenomenon that can potentially explain flat transmission spectra over some spectral regions.

  17. Atmospheric impact of the 1783–1784 Laki eruption: Part I Chemistry modelling

    Directory of Open Access Journals (Sweden)

    D. S. Stevenson

    2003-01-01

    Full Text Available Results from the first chemistry-transport model study of the impact of the 1783–1784 Laki fissure eruption (Iceland: 64°N, 17°W upon atmospheric composition are presented. The eruption released an estimated 61 Tg(S as SO2 into the troposphere and lower stratosphere. The model has a high resolution tropopause region, and detailed sulphur chemistry. The simulated SO2 plume spreads over much of the Northern Hemisphere, polewards of ~40°N. About 70% of the SO2 gas is directly deposited to the surface before it can be oxidised to sulphuric acid aerosol. The main SO2 oxidants, OH and H2O2, are depleted by up to 40% zonally, and the lifetime of SO2 consequently increases. Zonally averaged tropospheric SO2 concentrations over the first three months of the eruption exceed 20 ppbv, and sulphuric acid aerosol reaches ~2 ppbv. These compare to modelled pre-industrial/present-day values of 0.1/0.5 ppbv SO2 and 0.1/1.0 ppbv sulphate. A total sulphuric acid aerosol yield of 17–22 Tg(S is produced. The mean aerosol lifetime is 6–10 days, and the peak aerosol loading of the atmosphere is 1.4–1.7 Tg(S (equivalent to 5.9–7.1 Tg of hydrated sulphuric acid aerosol. These compare to modelled pre-industrial/present-day sulphate burdens of 0.28/0.81 Tg(S, and lifetimes of 6/5 days, respectively. Due to the relatively short atmospheric residence times of both SO2 and sulphate, the aerosol loading approximately mirrors the temporal evolution of emissions associated with the eruption. The model produces a reason-able simulation of the acid deposition found in Greenland ice cores. These results appear to be relatively insensitive to the vertical profile of emissions assumed, although if more of the emissions reached higher levels (>12 km, this would give longer lifetimes and larger aerosol yields. Introducing the emissions in episodes generates similar results to using monthly mean emissions, because the atmospheric lifetimes are similar to the repose periods

  18. Impact of dust storm on chemical species of S, Cl and Ca in Shanghai atmosphere particles

    International Nuclear Information System (INIS)

    Background: Dust storm originated from the northwest region of China brought dust particles for Shanghai every spring, which resulted in serious particulate pollution. However, the studies of the impact of dust storm on the Shanghai atmospheric aerosols were limited to the concentrations of ions and elements. It is considered that the chemical species of atmospheric aerosols were much more necessary for the evaluation of the impact of dust storm on the particulate pollution in Shanghai. Purpose: Based on the elements concentration variations, backward trajectories of air masses and chlorine, calcium, sulfur species in aerosols during the dust event, the impact of dust storm on the chemical species of aerosols in Shanghai was studied. Methods: Elements concentrations of the samples were analyzed by X-ray fluorescence (XRF) based on synchrotron radiation. To identify the potential importance of different source regions on aerosol composition during dust events, the air mass trajectories were calculated by using the model HYSPLIT version 4 developed by NOAA/ARL. Chemical species of S, Cl, Ca were analyzed by synchrotron radiation X-ray absorption near edge structure (XANES). Sulfur K-edge XANES is capable of distinguishing various sulfate species in a non-destructive way and we used linear combination fitting procedure to quantify the concentrations of sulfate species in PM. Results: Elements concentration variations during the dust storm period showed that crust elements (Si, Al, Ca, K, Mg, Fe, Ti) in particles increased substantially during dust storm. However, pollution elements (S, Zn, Pb, Cu, V, Cr, As) from local region decreased by the clean effect of dust storm. Combined XANES of S, Cl, Ca in particulate samples with backward trajectories, the possible sources and reasons of their chemical species were studied. During dust storm, sulfur mainly existed as CaSO4·2H2O, Cl existed as organic chloride and Cl-, Ca existed as CaCO3. In the samples of other days

  19. Impact of difference in absorption line parameters in spectroscopic databases on CO2 and CH4 atmospheric content retrievals

    Science.gov (United States)

    Chesnokova, T. Yu.; Chentsov, A. V.; Rokotyan, N. V.; Zakharov, V. I.

    2016-09-01

    The impact of uncertainties in CH4 and CO2 absorption line parameters in modern spectroscopic databases on the atmospheric transmission simulation in the near-infrared region is investigated. The atmospheric contents of CH4 and CO2 are retrieved from the absorption solar spectra measured by a ground-based Fourier transform spectrometer. Different spectroscopic databases are used in the forward radiative transfer model and a comparison of the retrieved results is made.

  20. Dust storms and their impact on ocean and human health: dust in Earth's atmosphere

    Science.gov (United States)

    Griffin, Dale W.; Kellog, Christina A.

    2004-01-01

    Satellite imagery has greatly influenced our understanding of dust activity on a global scale. A number of different satellites such as NASA's Earth-Probe Total Ozone Mapping Spectrometer (TOMS) and Se-viewing Field-of-view Sensor (SeaWiFS) acquire daily global-scale data used to produce imagery for monitoring dust storm formation and movement. This global-scale imagery has documented the frequent transmission of dust storm-derived soils through Earth's atmosphere and the magnitude of many of these events. While various research projects have been undertaken to understand this normal planetary process, little has been done to address its impact on ocean and human health. This review will address the ability of dust storms to influence marine microbial population densities and transport of soil-associated toxins and pathogenic microorganisms to marine environments. The implications of dust on ocean and human health in this emerging scientific field will be discussed.

  1. Impact of Altitudes and Habitats on Valerenic Acid, Total Phenolics, Flavonoids, Tannins, and Antioxidant Activity of Valeriana jatamansi.

    Science.gov (United States)

    Jugran, Arun K; Bahukhandi, Amit; Dhyani, Praveen; Bhatt, Indra D; Rawal, Ranbeer S; Nandi, Shyamal K

    2016-07-01

    The changes in total phenolics, flavonoids, tannins, valerenic acid, and antioxidant activity were assessed in 25 populations of Valeriana jatamansi sampled from 1200 to 2775 m asl and four habitat types of Uttarakhand, West Himalaya. Significant (p < 0.05) variations in total phenolics, flavonoids, valerenic acid, and antioxidant activity in aerial and root portions and across the populations were observed. Antioxidant activity measured by three in vitro antioxidant assays, i.e., 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) (ABTS) radical scavenging, 2,2'-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging, and ferric-reducing antioxidant power (FRAP) assays, showed significant (p < 0.05) differences across the populations. However, no clear pattern was found in phytochemicals across the altitudinal range. Among habitat types, (pine, oak, mixed forest, and grassy land), variation in phytochemical content and antioxidant activity were observed. Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity. The results recommended that the identified populations with higher value of phytochemicals and antioxidants can be utilized for mass multiplication and breeding program to meet the domestic as well as commercial demand. PMID:26971960

  2. Impact of Urban Surface Roughness Length Parameterization Scheme on Urban Atmospheric Environment Simulation

    Directory of Open Access Journals (Sweden)

    Meichun Cao

    2014-01-01

    Full Text Available In this paper, the impact of urban surface roughness length z0 parameterization scheme on the atmospheric environment simulation over Beijing has been investigated through two sets of numerical experiments using the Weather Research and Forecasting model coupled with the Urban Canopy Model. For the control experiment (CTL, the urban surface z0 parameterization scheme used in UCM is the model default one. For another experiment (EXP, a newly developed urban surface z0 parameterization scheme is adopted, which takes into account the comprehensive effects of urban morphology. The comparison of the two sets of simulation results shows that all the roughness parameters computed from the EXP run are larger than those in the CTL run. The increased roughness parameters in the EXP run result in strengthened drag and blocking effects exerted by buildings, which lead to enhanced friction velocity, weakened wind speed in daytime, and boosted turbulent kinetic energy after sunset. Thermal variables (sensible heat flux and temperature are much less sensitive to z0 variations. In contrast with the CTL run, the EXP run reasonably simulates the observed nocturnal low-level jet. Besides, the EXP run-simulated land surface-atmosphere momentum and heat exchanges are also in better agreement with the observation.

  3. Changes in Emissions in Megacities during the Past Decades: Impact on the Distribution of Atmospheric Compounds

    Science.gov (United States)

    Doumbia, E. H. T.; Granier, C.; Sindelarova, K.; Tilmes, S.; Bouarar, I.; Richter, A.; Hilboll, A.; Conley, A. J.; Garcia, R. R.; Kinnison, D. E.; Lamarque, J. F.; Marsh, D. R.; Smith, A. K.; Neely, R.; Turnock, S.

    2015-12-01

    The surface emissions of atmospheric compounds have changed dramatically in many world regions during the past decades. We will evaluate these changes through an analysis of different global and regional anthropogenic emissions inventories, focusing on several megacities. In European and North American megacities, surface emissions of chemical compounds have decreased significantly, while they have increased in many other megacities in different parts of the world. Simulations performed with the CAM4-Chem Community Earth System Model will be used to evaluate the impact of the changes in emissions on the distributions chemical compounds in different megacities. These simulations were performed as part of the Chemistry-Climate Model Initiative (CCMI), a project of the International Global Atmospheric Chemistry Project (IGAC). The analysis of the simulations will focus more particularly on nitrogen dioxide: this species has been observed by satellite measurements since the late 1990s. Model results and satellite observations will be analysed for everal megacities in Europe and North America, where strong emission controls have been implemented. Other megacities in China, India, Africa and South America, where few emission regulations have been enforced have seen large increases in their emissions: we will evaluate the consistency of the model simulations and satellite observations of NO2 in these cities.

  4. Will greater shrub abundance greatly impact tundra surface-atmosphere exchanges of energy and carbon?

    Science.gov (United States)

    Humphreys, E.; Lafleur, P.

    2015-12-01

    Increasing deciduous shrub abundance, productivity, and range in the Arctic comes with the potential for both negative and positive feedbacks to the climate system. This study presents six seasons of eddy covariance measurements of carbon dioxide (CO2) and latent and sensible heat fluxes along a shrub gradient in Canada's Low Arctic. Three flux tower sites with 17, 45, and 64% dwarf birch cover were established within a few kilometers of each other to investigate differences in microclimate, energy and carbon exchanges. As expected, there was greater winter snow depth but less summer soil thaw with greater shrub cover. However, snowmelt timing and speed were usually similar among sites. Despite a reduction in albedo in spring and greater leaf area through summer, latent heat fluxes were consistently lower with greater shrub cover. Offset by small differences in sensible heat fluxes, total seasonal atmospheric heating (combined sensible and latent heat fluxes) was similar among sites. We anticipated greater net uptake of CO2 through the growing season with greater shrub cover. However, that was only the case in some years. There was much more week-to-week and year-to-year variability in CO2 fluxes at the shrubbiest site suggesting photosynthesis and respiration processes were more sensitive to weather variations. Shrub abundance does impact tundra surface-atmosphere exchanges of energy and carbon but these observations also highlight the complexity involved in predicting the net climate feedback effect of current and future Arctic vegetation change.

  5. Methane emission by termites: Impacts on the self-cleansing mechanisms of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mugedo, J.Z.A. [Maseno Univ. College (Kenya)

    1996-12-31

    Termites are reported to emit large quantities of methane, carbon dioxide, carbon monoxide, hydrogen and dimethyl sulfide. The emission of other trace gases, namely C{sub 2} to C{sub 10} hydrocarbons, is also documented. We have carried out, both in the field and in the laboratory, measurements of methane emissions by Macrotermes subhyalinus (Macrotermitinae), Trinervitermes bettonianus (Termitinae), and unidentified Cubitermes and Microcerotermes species. Measured CH{sub 4} field flux rates ranged from 3.66 to 98.25g per m{sup 2} of termite mound per year. Laboratory measurements gave emission rates that ranged from 14.61 to 165.05 mg CH{sub 4} per termite per year. Gaseous production in all species sampled varied both within species and from species to species. Recalculated global emission of methane from termites was found to be 14.0 x 10{sup 12} g CH{sub 4}, per year. From our study, termites contribution to atmospheric methane content is between 1.11% and 4.25% per year. This study discusses the greenhouse effects as well as photochemical disposal of methane in the lower atmosphere in the tropics and the impacts on the chemistry of HO{sub x} systems and CL{sub x} cycles.

  6. Investigation the efficiency of various methods of volatile oil extraction from Trichodesma africanum and their impact on the antioxidant and antimicrobial activities

    OpenAIRE

    Jaradat, Nidal Amin; Zaid, Abdel Naser; Abuzant, Aladdin; Shawahna, Ramzi

    2016-01-01

    Background: Currently, there is an increasing interest in developing more efficient techniques for the extraction of phytochemicals. Microwaves and ultrasonic extraction methods are promising techniques that can be used for this purpose. Objectives: The purpose of this study was to investigate the impact of different extraction methods on yield, antioxidant and antimicrobial activities of volatile oil extracted from Trichodesma africanum. Materials and Methods: Volatile oil was extracted usin...

  7. The Impact of Atmospheric InfraRed Sounder (AIRS) Profiles on Short-term Weather Forecasts

    Science.gov (United States)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovec, Gary J.; Lapenta, William

    2007-01-01

    The Atmospheric Infrared Sounder (AIRS), together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced spacebased atmospheric sounding systems. The combined AlRS/AMSU system provides radiance measurements used to retrieve temperature profiles with an accuracy of 1 K over 1 km layers under both clear and partly cloudy conditions, while the accuracy of the derived humidity profiles is 15% in 2 km layers. Critical to the successful use of AIRS profiles for weather and climate studies is the use of profile quality indicators and error estimates provided with each profile Aside form monitoring changes in Earth's climate, one of the objectives of AIRS is to provide sounding information of sufficient accuracy such that the assimilation of the new observations, especially in data sparse region, will lead to an improvement in weather forecasts. The purpose of this paper is to describe a procedure to optimally assimilate highresolution AIRS profile data in a regional analysis/forecast model. The paper will focus on the impact of AIRS profiles on a rapidly developing east coast storm and will also discuss preliminary results for a 30-day forecast period, simulating a quasi-operation environment. Temperature and moisture profiles were obtained from the prototype version 5.0 EOS science team retrieval algorithm which includes explicit error information for each profile. The error profile information was used to select the highest quality temperature and moisture data for every profile location and pressure level for assimilation into the ARPS Data Analysis System (ADAS). The AIRS-enhanced analyses were used as initial fields for the Weather Research and Forecast (WRF) system used by the SPORT project for regional weather forecast studies. The ADASWRF system will be run on CONUS domain with an emphasis on the east coast. The preliminary assessment of the impact of the AIRS profiles will focus on quality control issues associated with AIRS

  8. An estimate of the impact of transient luminous events on the atmospheric temperature

    Directory of Open Access Journals (Sweden)

    E. Arnone

    2008-09-01

    Full Text Available We present an order of magnitude estimate of the impact of sprites and other transient luminous events (TLEs on the atmospheric temperature via ozone changes. To address the effects of expected TLE-ozone changes of at most a few percent, we first study the linearity of the radiatively driven response of a stratosphere-mesosphere model and of a general circulation model (GCM to a range of uniform climatological ozone perturbations. The study is limited to Northern Hemisphere winter conditions, when planetary wave activity is high and the non linear stratosphere-troposphere coupling can be strong. Throughout most of the middle atmosphere of both models, the radiatively driven temperature response to uniform 5% to 20% ozone perturbations shows a close-to linear relationship with the magnitude of the perturbation. A mid-latitude stratopause ozone perturbation is then imposed as an idealised experiment that mimics local temperature gradients introduced by the latitudinal dependence of TLEs. An unrealistically high 20% magnitude is adopted for the regional ozone perturbation to obtain statistical significance in the model response. The local linearity of the radiatively driven response is used to infer a first order estimate of TLE-induced temperature changes of the order of 0.015 K under typical conditions, and less than a peak temperature change of 0.3 K at 60–70 km height in coincidence of extraordinarily active TLE-producing thunderstorms before horizontal mixing quickly occurs. In the latter case, dedicated mesoscale modelling is needed to study the relevance of regional non linear processes which are expected to impact these radiatively driven responses.

  9. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 2: Aviation

    Directory of Open Access Journals (Sweden)

    M. Righi

    2015-12-01

    Full Text Available We use the EMAC (ECHAM/MESSy Atmospheric Chemistry global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications to simulate the impact of aviation emissions on global atmospheric aerosol and climate in 2030. Emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare our findings with the results of a previous study with the same model configuration focusing on year 2000 emissions. We also characterize the aviation results in the context of the other transport sectors presented in a companion paper. In spite of a relevant increase in aviation traffic volume and resulting emissions of aerosol (black carbon and aerosol precursor species (nitrogen oxides and sulfur dioxide, the aviation effect on particle mass concentration in 2030 remains quite negligible (on the order of a few ng m-3, about one order of magnitude less than the increase in concentration due to other emission sources. Due to the relatively small size of the aviation-induced aerosol, however, the increase in particle number concentration is significant in all scenarios (about 1000 cm-3, mostly affecting the northern mid-latitudes at typical flight altitudes (7–12 km. This largely contributes to the overall change in particle number concentration between 2000 and 2030, which results also in significant climate effects due to aerosol-cloud interactions. Aviation is the only transport sector for which a larger impact on the Earth's radiation budget is simulated in the future: The aviation-induced RF in 2030 is more than doubled with respect to the year 2000 value of −15 mW m-2, with a maximum value of −63 mW m-2 simulated for RCP2.6.

  10. Study of the impact of atmospheric emissions ({sup 41}AR) during operation of a nuclear reactor research

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Simone F.; Barreto, Alberto A.; Jacomino, Vanusa Maria F.; Rodrigues, Paulo Cesar H. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The knowledge of the atmosphere dispersion of radionuclides, resulting from a nuclear reactor emissions during normal operation, is an important step in the process of nuclear licensing and environmental. This step requires a study to evaluate the radiological environmental impact. The results of this study are used by radiation protection agents to control the exposure of public to radiation during the operation of nuclear facilities. The elaboration of environmental impact assessment due to atmospheric emissions is based on a study of atmospheric dispersion. The aim of this study is estimate the concentrations of radionuclides in different compartments of the ecosystem and calculate the dose received by man as a result of radiation exposure in different scenarios of interest. This paper deals with the case study of the impact of atmospheric emissions of {sup 41}Ar during operation of a nuclear research reactor. This study was accomplished with the application of the dispersion model ARTM (Radionuclide Transport Atmospheric Model), along with the geoprocessing resources. Among the results are: the spatial distribution of population by age; topography of the region, local wind rose, atmospheric stability and the estimate of the concentration of radionuclide {sup 41}Ar and of dose. The results indicate that the dose, by external irradiation due to immersion in the cloud, was below the limits established by regulatory agencies. (author)

  11. Impact of continental outflow on chemistry of atmospheric aerosols over tropical Bay of Bengal

    Directory of Open Access Journals (Sweden)

    B. Srinivas

    2011-07-01

    Full Text Available The continental outflow from Indo-Gangetic Plain and south-east Asia dominates the widespread dispersal of pollutants over tropical Bay of Bengal (BoB during the late NE-monsoon (January–March. It is thus pertinent to assess the impact on marine atmospheric boundary layer of BoB. The chemical data, based on analyses of size-segregated (PM2.5 and PM10 aerosols, suggest the dominance of nss-SO42− (range: 1.3 to 28 μg m−3 in PM2.5. Almost all SO42− is of anthropogenic origin and accounts for as much as 65 % of the water-soluble inorganic constituents. The impact of anthropogenic sources is further evident from the widespread depletion of chloride (range: 40 to 100 % compared to sea-salt composition. The carbonaceous species (EC and OC contribute nearly 25 % to PM2.5; and significant linear relationship with K+ suggests biomass burning as their dominant source (biofuels and agricultural waste. The enhancement in the fractional solubility of aerosol Fe, as assessed in PM2.5, re-emphasizes the impact of combustion sources (biomass and fossil-fuel and chemical processing (of dust during the long-range transport. The high enrichment factors of heavy metals (Pb and Cd further demonstrate the influence of pollution sources on the chemistry of MABL. The downwind transport of pollutants and exchange across air-sea interface can, thus, have profound impact on the ocean surface biogeochemistry.

  12. Impact of atmospheric refraction: How deeply can we probe exo-Earth's atmospheres during primary eclipse observations?

    OpenAIRE

    Betremieux, Y.; Kaltenegger, L.

    2013-01-01

    Most models used to predict or fit exoplanet transmission spectra do not include all the effects of atmospheric refraction. Namely, the angular size of the star with respect to the planet can limit the lowest altitude, or highest density and pressure, probed during primary eclipses, as no rays passing below this critical altitude can reach the observer. We discuss this geometrical effect of refraction for all exoplanets, and tabulate the critical altitude, density and pressure for an exoplane...

  13. Antioxidant properties of caroot juices and their impact on intestinal and probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Aleksandra Duda-Chodak

    2015-08-01

    Full Text Available There is a growing interest in non-dairy probiotic products. The main aim of the study was to evaluate the impact of juice prepared from 15 various cultivars of carrot on the growth of representatives of human intestinal microbiota (Bifidobacterium catenulatum, Escherichia coli and probiotic strains (Lactobacillus acidophilus LA-5, Lactobacillus casei 01. Carrot juice was added to liquid medium at a final concentration of 5.0% and their impact on the bacteria number was assessed by measurement of the turbidity after 24 h of culture. The number of cells was expressed as % of positive control (medium without juice addition. Juices prepared from all tested cultivars of carrot inhibited the growth of Bifidobacterium catenulatum, and the strongest inhibitory effect was observed for juices obtained from the 'Kongo F1' cultivar (3.40 ±2.85% of positive control, 'Rumba F1'(4.17 ±2.27% and 'Broker F1' (5.35 ±2.14%. The majority of tested juices also inhibited the growth of E. coli, but those prepared from the 'Niland F1', 'Napa F1', 'Afro F1'and 'Samba F1' cultivars stimulated the growth of this bacterium. The probiotic strains were less sensitive to carrot juice impact than intestinal species, however both stimulation and inhibition could be observed. Juices made from the cultivars 'Kongo F1' and 'Deep Purple F1' acted negatively on the growth of both probiotic strains, while juice from 'Bangor F1' cultivar inhibited L. casei 01 growth, but stimulated the growth of LA-5. The obtained results suggest that 'Kongo F1' and 'Deep Purple F1' cultivars are not suitable as an additive or raw material for the production of probiotic products, because of their inhibitory properties against probiotic strains. Concluding, carrots can be used as raw material for the production of probiotic beverages, however both the cultivar of carrot and the strains of probiotic bacteria used for the production should be selected carefully. The most suitable for production of

  14. Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

    International Nuclear Information System (INIS)

    The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. - Biomonitoring Spatial and Temporal dust emissions in dry climates

  15. Temporal Evolution and Atmospheric Impacts of Tropospheric Volcanic Emissions from In-Situ Measurements and Modelling

    Science.gov (United States)

    Roberts, Tjarda

    2010-05-01

    Assessment of the impact of tropospheric volcanic gas and aerosol emissions requires integration of observation and modelling. Knowledge and understanding is rapidly advancing in both areas, particularly due to the development of kinetic plume models of reactive halogen chemistry, and due to recent advances in measurement techniques for collecting in situ measurements of plume physico-chemical properties (i.e. using meteorological balloon and aircraft platforms), as well as a proliferation of remote sensing DOAS measurements. Here, we demonstrate this synergic relationship through model-observation plume studies. Volcanoes are a large natural source of SO2 and sulphate to the atmosphere, as is well demonstrated from both observational and model studies. In a recent study that deployed quasi-Lagrangian balloons in emissions at Kilauea volcano, Hawaii, both H2O(g) and SO2(g) were measured in situ, in the downwind plume. The observations showed periods of both correlation and anti-correlation between SO2 and water-vapour, implying the occurrence of both source and sink processes. Co-emission of volcanic H2O with SO2 accounts for the correlation. We use a thermodynamic model along the plume transect to assess how H2O-sulphate interactions might account for H2O anti-correlation with SO2 within the plume to elucidate in-plume sulphate formation, both near-vent (as predicted by high-T thermodynamic models) and downwind (as predicted by kinetic models). Volcanoes are a source of halogens (HBr, HCl) to the atmosphere, and volcanic plumes are highly reactive zones, not only in the high-temperature region near the vent, but also in the downwind plume where autocatalytic chemistry cycles produce reactive halogens such as BrO, first discovered from DOAS observations. The rapid formation of BrO can be reproduced through modelling which predicts high concentrations (reaching ppbv) on short formation timescales (minutes). Simulations using the PlumeChem model (developed to analyse

  16. Biological aerosol particles in the atmosphere and their impact on clouds (BIOCLOUDS)

    Science.gov (United States)

    Amato, Pierre; Attard, Eleonore; Deguillaume, Laurent; Delort, Anne-Marie; Flossmann, Andrea; Good, Nicholas; Joly, Muriel; Koop, Thomas; Möhler, Ottmar; Monier, Marie; Morris, Cindy; Oehm, Caroline; Pöschl, Ulrich; Sancelme, Martine

    2015-04-01

    The project BIOCLOUDS aimed at investigating and quantifying the role of bioaerosols in tropospheric clouds. We focused on the studies on microorganisms, mainly bacteria. To reach our objective we (1) isolated and identified INA bacterial strains in cloud waters, (2) studied in more details IN properties of bacteria isolated from cloud waters in laboratories and cloud chamber, (3) used new data as input to cloud models. 1. Isolation and Identification of INA bacterial strains in cloud waters Cloud water samples were collected at the puy de Dôme station under sterile conditions, microorganisms were cultured on agar plates and further identified by DNA sequencing coding for16SrRNA. 257 bacterial strains isolated from 25 cloud events were screened and 44 isolates were selected as they belonged to Pseudomonas, Xanthomonas and Erwinia genera which are potential INA candidates. Using the classical "Droplet Freezing method" as ice nucleation test, 7 strains were shown INA+. Their cumulative IN frequency profiles were established and showed that some of them are very efficient, for example the strain Pseudomonas syringae 13b74 started to nucleate a t-3°C and 4% of the cells were active at- 5°C. 2. Further laboratory investigations of IN properties of cloud bacterial strains All the experiments presented in this section were carried out with 3 Pseudomonas syringae strains. We tested the influence of O3, NO, UV and pH, which are atmospheric markers of anthropogenic activity, on the IN activity of the Pseudomonas strains. It was clearly shown that pH had a main influence, acidic pHs decreased the IN activity of the strains. This suggests a negative impact of human emissions on the natural capacity of bacteria to precipitate with rain. The 3 Pseudomas strains were sprayed in the AIDA cloud chamber. The survival of these strains with time before cloud formation was measured and will be used in the future to parameterize models for bacterial transport. After cloud formation

  17. The impact of deforestation in the Amazonian atmospheric radiative balance: a remote sensing assessment

    Directory of Open Access Journals (Sweden)

    E. T. Sena

    2012-06-01

    Full Text Available This paper addresses the Amazonian radiative budget after considering three aspects of deforestation: (i the emission of aerosols from biomass burning due to forest fires; (ii changes in surface albedo after deforestation and (iii modifications in the column water vapour amount over deforested areas. Simultaneous Clouds and the Earth's Radiant Energy System (CERES shortwave fluxes and aerosol optical depth (AOD retrievals from the Moderate Resolution Imaging SpectroRadiometer (MODIS were analysed during the peak of the biomass burning seasons (August and September from 2000 to 2009. A discrete-ordinate radiative transfer (DISORT code was used to extend instantaneous remote sensing radiative forcing assessments into 24-h averages. The mean direct radiative forcing of aerosols at the top of the atmosphere (TOA during the biomass burning season for the 10-yr studied period was −5.6 ± 1.7 W m−2. Furthermore, the spatial distribution of the direct radiative forcing of aerosols over Amazon was obtained for the biomass burning season of each year. It was observed that for high AOD (larger than 1 at 550 nm the imbalance in the radiative forcing at the TOA may be as high as −20 W m−2 locally. The surface reflectance plays a major role in the aerosol direct radiative effect. The study of the effects of biomass burning aerosols over different surface types shows that the direct radiative forcing is systematically more negative over forest than over savannah-like covered areas. Values of −15.7 ± 2.4 W m−2550 nm and −9.3 ± 1.7 W m−2550 nm were calculated for the mean daily aerosol forcing efficiencies over forest and savannah-like vegetation respectively. The overall mean annual albedo-change radiative forcing due to deforestation over the state of Rondônia, Brazil, was determined as −7.3 ± 0.9 W m−2. Biomass burning aerosols impact the radiative

  18. Impacts of near-future cultivation of biofuel feedstocks on atmospheric composition and local air quality

    Science.gov (United States)

    Ashworth, K.; Folberth, G.; Hewitt, C. N.; Wild, O.

    2012-01-01

    Large-scale production of feedstock crops for biofuels will lead to land use changes. We quantify the effects of realistic land use change scenarios for biofuel feedstock production on isoprene emissions and hence atmospheric composition and chemistry using the HadGEM2 model. Two feedstocks are considered: oil palm for biodiesel in the tropics and short rotation coppice (SRC) in the mid-latitudes. In total, 69 Mha of oil palm and 9 Mha of SRC are planted, each sufficient to replace just over 1% of projected global fossil fuel demand in 2020. Both planting scenarios result in increases in total global annual isoprene emissions of about 1%. In each case, changes in surface concentrations of ozone and biogenic secondary organic aerosol (bSOA) are substantial at the regional scale, with implications for air quality standards. However, the changes in tropospheric burden of ozone and the OH radical, and hence effects on global climate, are negligible. Over SE Asia, one region of oil palm planting, increases in annual mean surface ozone and bSOA concentrations reach over 3 ppbv (+11%) and 0.4 μg m-3 (+10%) respectively for parts of Borneo, with monthly mean increases of up to 6.5 ppbv (+25%) and 0.5 μg m-3 (+12%). Under the SRC scenario, Europe experiences monthly mean changes of over 0.6 ppbv (+1%) and 0.1 μg m-3 (+5%) in June and July, with peak increases of over 2 ppbv (+3%) and 0.5 μg m-3 (+8 %). That appreciable regional atmospheric impacts result from low level planting scenarios demonstrates the need to include changes in emissions of reactive trace gases such as isoprene in life cycle assessments performed on potential biofuel feedstocks.

  19. Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2012-08-01

    Full Text Available The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B, and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE, presented in a companion paper, and with the recent past (year 2000. Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario.

    As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000.

    Radiative Forcing (RF calculations show that the net effect of AIR, SHIP and ROAD combined will change from a~marginal cooling of −0.38 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 8.9 (B1 or −31 ± 20 mW m−2 (A1B in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −20 ± 5.4 mW m−2 in 2000 to

  20. Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2012-12-01

    Full Text Available The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B, and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE, presented in a companion paper, and with the recent past (year 2000. Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario.

    As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000.

    Radiative forcing (RF calculations show that the net effect of AIR, SHIP and ROAD combined will change from a marginal cooling of −0.44 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 9.3 (B1 or −32 ± 18 mW m−2 (A1B in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −19 ± 5.3 mW m−2 in 2000 to

  1. Gamma irradiation of air-dried olive leaves : effective decontamination and impact on the antioxidative properties and on phenolic compounds

    OpenAIRE

    Aouidi, F.; Ayari, S.; Ferhi, H.; Roussos, Sevastianos; M. Hamdi

    2011-01-01

    Olive leaves are commercialized for their antioxidative value due to their valuable phenolic compounds. The present study aimed to evaluate the effect of gamma irradiation on microbial load, on antioxidative properties and on phenolic compounds of air-dried olive leaves. Irradiation was applied up to 25 kGy (5 kGy intervals) to powdered and intact samples. Total aerobic bacteria, yeast and mold, and lactic acid bacteria were counted after gamma irradiation. Decontamination was obtained at 20 ...

  2. Estimating the Overall Impact of a Change in Agricultural Practices on Atmospheric CO(sub 2)

    International Nuclear Information System (INIS)

    One option for sequestering carbon in the terrestrial biosphere is to increase the carbon (C) stocks in agricultural soils. There is now an extensive literature on the amount of C that has been lost from soils as a consequence of humans disturbing natural ecosystems, and of the amount of C that might be returned to soils with improved management practices. Improvements in management practices could include efficient use of fertilizers and irrigation water, use of crop rotations, and changing from conventional tillage (CT) to conservation tillage (or, more specifically, to no-till (NT)). The Intergovernmental Panel on Climate Change (IPCC) has estimated that 55 x 10(sup 9) Mg of soil C have been lost, globally, largely as a result of cultivating former grasslands, forests, and wetlands. The IPCC estimated further that 22-29 x 10(sup 9) Mg of C could be returned to existing, world, agricultural soils under improved management regimes. Historical losses of soil organic C (SOC) in the US, due to cultivation, have been estimated to be 1.3(+-) 0.3 x 10(sup 9) Mg (Kern and Johnson 1993). Kern and Johnson projected that by increasing NT practice in the US from 27% in 1990 to 76%, a total of 0.4(+-) 0.1 x 10(sup 9) Mg C could be sequestered in the soil during the interval 1990-2020. These studies tend to focus on increasing the C stocks in soils rather than on the overall effect that changes in agricultural practice would have on C stocks in the atmosphere. Changing agricultural practice can impact net CO(sub 2) emissions to the atmosphere in three fundamental ways: (1) it can lead to an increase in the C held in agricultural soils, (2) it can lead to a change in emissions of CO(sub 2) from fossil fuel burning, and (3) it can change agricultural productivity, and hence the amount of cultivated land needed to meet the demand for agricultural products. Changing agricultural practice can also affect the net emissions of other greenhouse gases, such as N(sub 2)O emissions

  3. Atmospheric nitrogen deposition in world biodiversity hotspots: the need for a greater global perspective in assessing N deposition impacts

    NARCIS (Netherlands)

    Phoenix, G.K.; Hicks, W.K.; Cinderby, S.; Kuylenstierna, J.C.I.; Stock, W.D.; Dentener, F.J.; Giller, K.E.; Austin, A.T.; Lefroy, R.D.B.; Gimeno, B.S.; Ashmore, M.R.; Ineson, P.

    2006-01-01

    Increased atmospheric nitrogen (N) deposition is known to reduce plant diversity in natural and semi-natural ecosystems, yet our understanding of these impacts comes almost entirely from studies in northern Europe and North America. Currently, we lack an understanding of the threat of N deposition t

  4. PHOTOPROTECTIVE ANTIOXIDANT PHYTOCHEMICALS

    OpenAIRE

    Deore, Sharada L.; Saroj Kombade; Baviskar, Bhushan A.; Khadabadi, S. S.

    2012-01-01

    Many ayurvedic natural products have properties to rejuvenate and protect the skin from environmental pollution, chemicals, atmospheric temperature fluctuation, UVA and UVB radiation, wrinkling, hyperpigmentation (excessive tanning) and inflammation. The present review focuses on properties and mechanism of action of photoprotective antioxidant phytoconstituents obtained from ayurvedic plants such as flavonoids, carotenoids, phenolics which can be useful in development of effective photoprote...

  5. Aircraft Measurements of Saharan dust properties and impact of atmospheric transport during Fennec

    Science.gov (United States)

    Ryder, Claire; Highwood, Ellie; Rosenberg, Phil; Trembath, Jamie; Brooke, Jennifer; Bart, Mark; Dean, Angela; Dorsey, James; Crosier, Jonny; McQuaid, Jim; Brindley, Helen; Banks, James; Marsham, John; Sodemann, Harald; Washington, Richard

    2013-04-01

    Measurements of Saharan dust from recent airborne campaigns have found variations in size distributions and optical properties across Saharan and sub-Saharan Africa. These variations have an impact on radiation and thus weather and climate, and are important to characterise and understand, in particular, to understand how they vary with time after dust uplift, transport, and height in the atmosphere. New in-situ aircraft measurements from the Fennec 2011 aircraft campaign over a remote part of the Sahara Desert and the Atlantic Ocean will be presented and compared to previous airborne measurements. Size distributions extending to 300 μm will be shown, representing measurements extending further into the coarse mode than previously published for Saharan dust. The dust sampled by the aircraft covered a wide variety of loadings, dust source regions (Mali, Mauritania and Algeria) and dust ages (from fresh uplift to several days old). A significant coarse mode was present in the size distribution measurements with effective diameter up to 23 μm, and the mean size distribution showed greater concentrations of coarse mode than previous aircraft measurements. Single scattering albedo (SSA) values at 550nm calculated from these size distributions revealed high absorption from 0.77 to 0.95, with a mean of 0.85. Directly measured SSA values were higher (0.91 to 0.99) but new instrumentation revealed that these direct measurements, behind Rosemount inlets, overestimate the SSA by 0.02 to 0.20 depending on the concentration of coarse particles present. This is caused by inlet inefficiencies and pipe losses. Previous measurements of SSA from aircraft measurements may also have been overestimates for this reason. This has a significant impact on atmospheric heating rates. The largest dust particles were encountered closest to the ground, and were most abundant in cases where dust was freshly uplifted. Number concentration, mass loading and extinction coefficient showed inverse

  6. Understanding the impact of plant competition on the coupling between vegetation and the atmosphere.

    NARCIS (Netherlands)

    van Loon, M.P.; Dekker, S.C.; Anten, Niels; Rietkerk, M.G.; de Arellano, Jordi Vila-Guerau

    2015-01-01

    Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation functioning and associated atmospheric interactions. Our aim was to investigate how the coupling between vegetation and atmosphere is influenced by plant

  7. Impact of atmospheric deposition on the metabolism of coastal microbial communities

    Science.gov (United States)

    Martínez-García, Sandra; Arbones, B.; García-Martín, E. E.; Teixeira, I. G.; Serret, P.; Fernández, E.; Figueiras, F. G.; Teira, E.; Álvarez-Salgado, X. A.

    2015-02-01

    The impact of rain water collected at marine, urban and rural sites on coastal phytoplankton biomass, primary production and community composition as well as the effect on microbial plankton metabolism was studied in 3 microcosm experiments conducted under contrasting spring, autumn and winter conditions. The measured responses were highly variable. Rainwater additions increased chlorophyll a (Chl a) concentration (5-68% difference between rainwater treatments relative to the control) in all experiments and reduced or stimulated primary production (PP) depending on the treatment and the experiment (from -10 to +169% relative to the control). Autotrophic stimulation was highest in spring, probably related to the low initial natural nutrient concentrations. Under winter nutrient replete conditions, rainwater inputs changed the phytoplankton community although this change did not promote increases in primary production. Enhancement of net autotrophy (increase of net oxygen production up to 227%) after rainwater inputs were only found during the period of low nutrient availability. Inputs of dissolved organic nitrogen (DON) explained a large fraction of the variability in the response of PP, Chl a, community respiration (CR) and net community production (NCP). Our results suggest that differences in the initial environmental conditions (i.e. nutrient availability), rainwater composition and the ability of the present autotrophic communities to utilize the new nutrients result in substantial changes in the microbial responses and associated biologically-mediated carbon fluxes. As atmospheric nutrient inputs into coastal oceans are increasing rapidly, our results help to understand the effects of different inputs on the metabolism of distinct microbial communities.

  8. Macro Impact of the Law on Prevention and Control of Atmospheric Pollution on Power Industry Development

    Institute of Scientific and Technical Information of China (English)

    王志轩

    2001-01-01

    The newly revised and enlarged main contents of the Law ofPrevention and Control of Atmospheric Pollution are described. The macro impacts of the law on the power industry development are analyzed mainly in respects to power demand and readjustment of power structure and layout, clean production and pollution control level, scientific management of environmental protection, in accordance with law as well as changes of construction and operation costs. And finally, several questions worthy to be noted in course of implementation of the new law are enumerated.%阐述大气污染防治法新修订的主要内容;重点从电力需求、结构和布局调整、生产和污染控制水平、依法对环境保护进行科学管理、建设和运行成本变化等方面分析大气法对电力发展的宏观影响;提出电力企业在贯彻大气法中应注意的事项。

  9. A reappraisal of the 1835 eruption of Cosigüina and its atmospheric impact

    Science.gov (United States)

    Self, S.; Rampino, M. R.; Carr, M. J.

    1989-10-01

    In the “great” January 1835 eruption of Cosigüina volcano, Nicaragua, andesitic magma and lithic material were erupted over a period of at least three days. Proximal facies consist of clastogenic lava, scoria-fall, and lithic ash-fall produced by phreatomagmatic to vulcanian or plinian activity, together with surge deposits and lithic block-falls. Pyroclastic flow deposits covered some flanks of the volcano and entered the sea in the Gulf of Fonseca. Little record exists of the distal ash-fall, thus the total bulk volume erupted can only be roughly constrained to 2.9 5.6 km3. Furthermore, the amount of juvenile material is thought to be small. A recent study of volatiles in 1835 scoria suggests sulfur release from the magma was negligible. This reappraisal indicates that the Cosigüina eruption probably had little global climatic impact. Despite its violent nature, the magnitude of the eruption was modest. The eruption occurred too late to initiate the Northern Hemisphere cooling trend form 1828 1836. Dry fogs and other atmospheric optical phenomena usually observed after eruptions that contribute significantly to the stratospheric aerosol burden were not recorded after 1835.

  10. Energetic electron precipitation impacts on the middle atmosphere: From satellite observations to chemistry-climate modeling

    Science.gov (United States)

    Sinnhuber, Miriam; Bender, Stefan; Burrows, John P.; Funke, Bernd; Fytterer, Tilo; Nieder, Holger; Reddmann, Thomas; Stiller, Gabriele; Versick, Stefan; von Clarmann, Thomas; Maik Wissing, Jan

    2016-04-01

    Precipitation of energetic particles - mainly protons from solar coronal mass ejections or electrons accelerated in auroral or geomagnetic storms - directly affects the mesosphere and lower thermosphere. Nitric oxides (N, NO, NO2) and hydrogen radicals (H, OH) are formed by particle impact dissociation and ionization and subsequent ion chemistry reactions. However, the stratosphere and possibly even tropospheric weather systems can be affected indirectly by downward transport of particle-induced nitric oxides from their source regions into the stratosphere during polar winter, subsequent ozone depletion, and dynamical feedbacks with radiative (ozone) heating and cooling. This so-called "EPP indirect effect" forms one aspect of solar-climate interactions which will be recommended to include in chemistry-climate models, e.g., in the upcoming CMIP-6 experiment. We will present recent observations of mesospheric nitric oxide formation due to particle precipitation, as well as downwelling of particle induced NOy. Observations are compared to results from three 3-dimensional global chemistry-climate and chemistry-transport models of the middle atmosphere, and the subsequent ozone depletion is assessed using CCM / CTM model results.

  11. The Impact of Agricultural Practices in China on Land-Atmosphere Interactions

    Institute of Scientific and Technical Information of China (English)

    XU Xingkui; Jason K.LEVY

    2011-01-01

    Human-induced land usc changes and the resulting alterations in vegetation features are major but poorly recognized drivers of regional climatic patterns. In order to investigate the impacts of anthropoghnicallyinduced seasonal vegetation cover changes on regional climate in China, harmonic analysis is applied to 1982 2000 National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radioneter (AVVHRR)-derived normalized difference vegetation index (NDVI) time series (ten day interval data). For two climatic divisions of South China, it is shown that the first harmonic term is in phase with air temperature, while the second and third harmonics are in phase with agricultural cultivation.The Penman-Monteith Equation and the Complementary Relationship Areal Evapotranspiration (CRAE)model suggest that monthly mean evapotranspiration is out of phase with temperature and precipitation in regions with significant second or third harnouics. Finally, seasonal vegetation cover changes associated with agricultural cultivation are identified: for cropped areas, the temperature and precipitation time series have a single maximum value, while the monthly evapotranspiration time series has a bimodal distribution.It is hypothesized that multi-cropping causes the land surface albedo to sharply increase during harvesting,thereby altering the energy distributiou ratio and contributing to observed seasonal vegetation cover changes.

  12. Impact of meteorological inflow uncertainty on tracer transport and source estimation in urban atmospheres

    Science.gov (United States)

    Lucas, Donald D.; Gowardhan, Akshay; Cameron-Smith, Philip; Baskett, Ronald L.

    2016-10-01

    A computational Bayesian inverse technique is used to quantify the effects of meteorological inflow uncertainty on tracer transport and source estimation in a complex urban environment. We estimate a probability distribution of meteorological inflow by comparing wind observations to Monte Carlo simulations from the Aeolus model. Aeolus is a computational fluid dynamics model that simulates atmospheric and tracer flow around buildings and structures at meter-scale resolution. Uncertainty in the inflow is propagated through forward and backward Lagrangian dispersion calculations to determine the impact on tracer transport and the ability to estimate the release location of an unknown source. Our uncertainty methods are compared against measurements from an intensive observation period during the Joint Urban 2003 tracer release experiment conducted in Oklahoma City. The best estimate of the inflow at 50 m above ground for the selected period has a wind speed and direction of 4.6-2.5+2.0 m s-1 and 158.0-23+16 , where the uncertainty is a 95% confidence range. The wind speed values prescribed in previous studies differ from our best estimate by two or more standard deviations. Inflow probabilities are also used to weight backward dispersion plumes and produce a spatial map of likely tracer release locations. For the Oklahoma City case, this map pinpoints the location of the known release to within 20 m. By evaluating the dispersion patterns associated with other likely release locations, we further show that inflow uncertainty can explain the differences between simulated and measured tracer concentrations.

  13. Impacts of the 2014-2015 Holuhraun eruption on the UK atmosphere

    Science.gov (United States)

    Twigg, Marsailidh M.; Ilyinskaya, Evgenia; Beccaceci, Sonya; Green, David C.; Jones, Matthew R.; Langford, Ben; Leeson, Sarah R.; Lingard, Justin J. N.; Pereira, Gloria M.; Carter, Heather; Poskitt, Jan; Richter, Andreas; Ritchie, Stuart; Simmons, Ivan; Smith, Ron I.; Sim Tang, Y.; Van Dijk, Netty; Vincent, Keith; Nemitz, Eiko; Vieno, Massimo; Braban, Christine F.

    2016-09-01

    Volcanic emissions, specifically from Iceland, pose a pan-European risk and are on the UK National Risk Register due to potential impacts on aviation, public health, agriculture, the environment and the economy, from both effusive and explosive activity. During the 2014-2015 fissure eruption at Holuhraun in Iceland, the UK atmosphere was significantly perturbed. This study focuses one major incursion in September 2014, affecting the surface concentrations of both aerosols and gases across the UK, with sites in Scotland experiencing the highest sulfur dioxide (SO2) concentrations. The perturbation event observed was confirmed to originate from the fissure eruption using satellite data from GOME2B and the chemical transport model, EMEP4UK, which was used to establish the spatial distribution of the plume over the UK during the event of interest. At the two UK European Monitoring and Evaluation Program (EMEP) supersite observatories (Auchencorth Moss, SE Scotland, and Harwell, SE England) significant alterations in sulfate (SO42-) content of PM10 and PM2.5 during this event, concurrently with evidence of an increase in ultrafine aerosol most likely due to nucleation and growth of aerosol within the plume, were observed. At Auchencorth Moss, higher hydrochloric acid (HCl) concentrations during the September event (max = 1.21 µg m-3, cf. annual average 0.12 µg m-3 in 2013), were assessed to be due to acid displacement of chloride (Cl-) from sea salt (NaCl) to form HCl gas rather than due to primary emissions of HCl from Holuhraun. The gas and aerosol partitioning at Auchencorth Moss of inorganic species by thermodynamic modelling confirmed the observed partitioning of HCl. Using the data from the chemical thermodynamic model, ISORROPIA-II, there is evidence that the background aerosol, which is typically basic at this site, became acidic with an estimated pH of 3.8 during the peak of the event.Volcano plume episodes were periodically observed by the majority of the UK

  14. Simulations of the impact of high pulse atmospheric deposition events on a low nutrient low chlorophyll (LNLC) marine ecosystem

    Science.gov (United States)

    Christodoulaki, Sylvia; Petihakis, George; Tsiaras, Konstantinos; Triantafyllou, George; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2014-05-01

    Nutrient availability controls ocean productivity and partitioning of carbon between the ocean and atmosphere, mediated by the limiting potential of macro and micronutrients such as N, P, Fe and Si. Atmospheric deposition is a major pathway for nutrient delivery with potential to alter the role of the ocean from a sink to a source of CO2 and vice versa. Mediterranean region is of interest for both its marine and atmospheric environments. Its Sea is one of the world's most oligotrophic regions in terms of both primary productivity and chlorophyll-a concentration. Its atmosphere is a cross road of air masses of distinct origin highly affected by both natural and anthropogenic emissions. These emissions strongly interact in the atmosphere, due to the high photochemical activity in the area, leading to the formation of nutrients such as nitrogen compounds. Dust aerosols from the African continent are also affecting the area and act as carriers of nutrients such as iron and phosphorus. In the Eastern Basin, where nutrient riverine inputs are very low, wet and dry atmospheric inputs of N and P are the main source of new nutrients in the euphotic zone of the open sea, particularly during the stratification period. In the present study, the impact of an intense atmospheric nitrogen and phosphorus deposition pulse event on the marine ecosystem in the East Mediterranean Sea is investigated. This is achieved by coupling atmospheric and sea water observations with a 1-D ocean physical-biogeochemical model, set up for the Cretan Sea as a representative E. Mediterranean open sea area (Christodoulaki et al., 2012, Journal of Marine Systems, doi: 10.1016/j.jmarsys.2012.07.007). Atmospheric deposition measurements of Dissolved Inorganic Phosphorous and Nitrogen are obtained from the station of Finokalia, shown to be a representative background station for atmospheric observations in the area, whereas, oceanographic data are obtained from the M3A station. Analysis of this high pulse

  15. Scenarios of atmospheric mass evolution on Mars influenced by asteroid and comet impacts since the late Noachian

    Science.gov (United States)

    Pham, L. B. S.; Karatekin, Ö.

    2016-06-01

    Early in its history, Mars probably had a denser atmosphere and higher surface temperatures to sustain the presence of stable liquid water or saline solution at the surface. Impacts by asteroids and comets could affect the atmospheric evolution of a planet, by removing part of its atmosphere and by delivering into it material and volatiles. In this study we investigate the atmospheric loss and delivery of volatiles between the end of the Noachian and present, with the help of a semi-analytic model. Our results suggest that impacts alone can hardly remove a significant amount of atmospheric mass over this period. Contribution of additional factors such as outgassing and non-thermal escape processes cannot explain neither the presence of surface pressure larger than few hundreds of mbars 3.9 Gyr ago, unless parameter values outside of their expected range are considered. Based on extreme case scenarios, maximum surface pressures at the end of the Noachian, could be as much as 0.25 bar or 1.9 bar, with and without CO2 storage into carbonate reservoirs, respectively.

  16. Characterization of a boreal convective boundary layer and its impact on atmospheric chemistry during HUMPPA-COPEC-2010

    Directory of Open Access Journals (Sweden)

    H. G. Ouwersloot

    2012-10-01

    Full Text Available We studied the atmospheric boundary layer (ABL dynamics and the impact on atmospheric chemistry during the HUMPPA-COPEC-2010 campaign. We used vertical profiles of potential temperature and specific moisture, obtained from 132 radio soundings, to determine the main boundary layer characteristics during the campaign. We propose a classification according to several main ABL prototypes. Further, we performed a case study of a single day, focusing on the convective boundary layer, to analyse the influence of the dynamics on the chemical evolution of the ABL. We used a mixed layer model, initialized and constrained by observations. In particular, we investigated the role of large scale atmospheric dynamics (subsidence and advection on the ABL development and the evolution of chemical species concentrations. We find that, if the large scale forcings are taken into account, the ABL dynamics are represented satisfactorily. Subsequently, we studied the impact of mixing with a residual layer aloft during the morning transition on atmospheric chemistry. The time evolution of NOx and O3 concentrations, including morning peaks, can be explained and accurately simulated by incorporating the transition of the ABL dynamics from night to day. We demonstrate the importance of the ABL height evolution for the representation of atmospheric chemistry. Our findings underscore the need to couple the dynamics and chemistry at different spatial scales (from turbulence to mesoscale in chemistry-transport models and in the interpretation of observational data.

  17. The impact of residential combustion emissions on atmospheric aerosol, human health, and climate

    Science.gov (United States)

    Butt, E. W.; Rap, A.; Schmidt, A.; Scott, C. E.; Pringle, K. J.; Reddington, C. L.; Richards, N. A. D.; Woodhouse, M. T.; Ramirez-Villegas, J.; Yang, H.; Vakkari, V.; Stone, E. A.; Rupakheti, M.; Praveen, P. S.; van Zyl, P. G.; Beukes, J. P.; Josipovic, M.; Mitchell, E. J. S.; Sallu, S. M.; Forster, P. M.; Spracklen, D. V.

    2016-01-01

    Combustion of fuels in the residential sector for cooking and heating results in the emission of aerosol and aerosol precursors impacting air quality, human health, and climate. Residential emissions are dominated by the combustion of solid fuels. We use a global aerosol microphysics model to simulate the impact of residential fuel combustion on atmospheric aerosol for the year 2000. The model underestimates black carbon (BC) and organic carbon (OC) mass concentrations observed over Asia, Eastern Europe, and Africa, with better prediction when carbonaceous emissions from the residential sector are doubled. Observed seasonal variability of BC and OC concentrations are better simulated when residential emissions include a seasonal cycle. The largest contributions of residential emissions to annual surface mean particulate matter (PM2.5) concentrations are simulated for East Asia, South Asia, and Eastern Europe. We use a concentration response function to estimate the human health impact due to long-term exposure to ambient PM2.5 from residential emissions. We estimate global annual excess adult (> 30 years of age) premature mortality (due to both cardiopulmonary disease and lung cancer) to be 308 000 (113 300-497 000, 5th to 95th percentile uncertainty range) for monthly varying residential emissions and 517 000 (192 000-827 000) when residential carbonaceous emissions are doubled. Mortality due to residential emissions is greatest in Asia, with China and India accounting for 50 % of simulated global excess mortality. Using an offline radiative transfer model we estimate that residential emissions exert a global annual mean direct radiative effect between -66 and +21 mW m-2, with sensitivity to the residential emission flux and the assumed ratio of BC, OC, and SO2 emissions. Residential emissions exert a global annual mean first aerosol indirect effect of between -52 and -16 mW m-2, which is sensitive to the assumed size distribution of carbonaceous emissions

  18. Peculiarities in the formation of complex organic compounds in a nitrogen-methane atmosphere during hypervelocity impacts

    Science.gov (United States)

    Zaitsev, M. A.; Gerasimov, M. V.; Safonova, E. N.; Vasiljeva, A. S.

    2016-03-01

    Results of the experiments on model impact vaporization of peridotite, a mineral analogue of stony asteroids, in a nitrogen-methane atmosphere are presented. Nd-glass laser (γ = 1.06 µm) was used for simulation. Pulse energy was ~600-700 J, pulse duration ~10-3 s, vaporization tempereature ~4000-5000 K. The gaseous medium (96% vol. of N2 and 4% vol. of CH4, P = 1 atm) was a possible analogue of early atmospheres of terrestrial planets and corresponded to the present-day atmosphere composition of Titan, a satellite of Saturn. By means of pyrolytic gas chromatography/mass spectrometry, it is shown that solid condensates obtained in laser experiments contain relatively complex lowand high-molecular weight (kerogen-like) organic compounds. The main products of condensate pyrolysis were benzene and alkyl benzenes (including long-chain ones), unbranched aliphatic hydrocarbons, and various nitrogen-containing compounds (aliphatic and aromatic nitriles and pyrrol). It is shown that the nitrogen-methane atmosphere favors the formation of complex organic compounds upon hypervelocity impacts with the participation of stony bodies even with a small methane content in it. In this process, falling bodies may not contain carbon, hydrogen, and other chemical elements necessary for the formation of the organic matter. In such conditions, a noticeable contribution to the impact-induced synthesis of complex organic substances is probably made by heterogeneous catalytic reactions, in particular, Fischer-Tropsch type reactions.

  19. Wet and dry extraction of coconut oil: impact on lipid metabolic and antioxidant status in cholesterol coadministered rats.

    Science.gov (United States)

    Nevin, K Govindan; Rajamohan, Thankappan

    2009-08-01

    Because coconut oil extracted by wet process (virgin coconut oil, VCO) is gaining popularity among consumers, this study was conducted to evaluate VCO compared with coconut oil extracted by dry process (copra oil, CO) for their influence on lipid parameters, lipid peroxidation, and antioxidant status in rats coadministered with cholesterol. VCO, CO, and cholesterol were fed in a semi-synthetic diet to 24 male Sprague-Dawley rats for 45 days. After the experimental period, lipid and lipid peroxide levels and antioxidant enzyme activities were observed. Chemical composition and antioxidant properties of the polyphenolic fraction from VCO and CO were also analyzed. The results showed that lipid and lipid peroxide levels were lower in VCO-fed animals than in animals fed either CO or cholesterol alone. Antioxidant enzyme activities in VCO-fed animals were comparable with those in control animals. Although the fatty acid profiles of both oils were similar, a significantly higher level of unsaponifiable components was observed in VCO. Polyphenols from VCO also showed significant radical-scavenging activity compared with those from CO. This study clearly indicates the potential benefits of VCO over CO in maintaining lipid metabolism and antioxidant status. These effects may be attributed in part to the presence of biologically active minor unsaponifiable components.

  20. Atmospheric coupling of Tsunami: observations from Tohoku and impact on tsunami physical properties and phase/group velocities

    Science.gov (United States)

    Lognonne, P. H.; Kherani, E. A.; Coisson, P.; Astafyeva, E.; Occhipinti, G.; Rolland, L. M.; Yahagi, T.; Khelfi, K.; Sladen, A.; Hebert, H.; Makela, J. J.

    2012-12-01

    Tsunamis, through a dynamic coupling between the ocean and atmosphere, are generating atmospheric waves, detected in the ionosphere for tsunamis with amplitudes as much as 1 cm in the open ocean. Signals associated to the Tohoku tsunami have therefore been observed with huge signal to noise ratio, not only over Japan, but all over the Pacific, up to Chili. These signals have been moreover modelled, not only for the Total Electronic Contents perturbation signals, but also of the airglow detected for the first time over Hawaii and for the magnetic perturbations detected in Japan. We present in this paper the two sides of this coupling. The first side resumes the different observations and modelling of the Tohoku ionospheric signals observed by GEONET, by the GSI magnetic network and by Airglow cameras in Hawaii and Chili. Comparison between data and modelling are shown. The second side present the effects of the atmospheric coupling on the tsunami properties, i.e. amplitudes, phase/group velocities and excitation coefficients. By taking into account the coupling of tsunami with both the solid Earth and atmosphere, we show that specific resonances between the ocean and the atmosphere exist, enabling to understand the large and peaked signal spectrum. Local Time and geographical variations of this coupling is studied, as well as its dependence with the ocean depth. The impacts of atmospheric coupling on the propagation travel time of tsunamis is finally presented and discussed.

  1. Impacts of near-future cultivation of biofuel feedstocks on atmospheric composition and local air quality

    Directory of Open Access Journals (Sweden)

    K. Ashworth

    2011-09-01

    Full Text Available Large-scale production of feedstock crops for biofuels will lead to land-use changes. We quantify the effects of realistic land use change scenarios for biofuel feedstock production on isoprene emissions and hence atmospheric composition and chemistry using the HadGEM2 model. Two feedstocks are considered: oil palm for biodiesel in the tropics and short rotation coppice (SRC in the mid-latitudes. In total, 69 Mha of oil palm and 92 Mha of SRC are planted, each sufficient to replace just over 1 % of projected global fossil fuel demand in 2020. Both planting scenarios result in increases in total global annual isoprene emissions of about 1 %. In each case, changes in surface concentrations of ozone and biogenic secondary organic aerosol (bSOA are significant at the regional scale and are detectable even at a global scale with implications for air quality standards. However, the changes in tropospheric burden of ozone and the OH radical, and hence effects on global climate, are negligible. The oil palm plantations and processing plants result in global average annual mean increases in ozone and bSOA of 38 pptv and 2 ng m−3 respectively. Over SE Asia, one region of planting, increases reach over 2 ppbv and 300 ng m−3 for large parts of Borneo. Planting of SRC causes global annual mean changes of 46 pptv and 3 ng m−3. Europe experiences peak monthly mean changes of almost 0.6 ppbv and 90 ng m−3 in June and July. Large areas of Central and Eastern Europe see changes of over 1.5 ppbv and 200 ng m−3 in the summer. That such significant atmospheric impacts from low level planting scenarios are discernible globally clearly demonstrates the need to include changes in emissions of reactive trace gases such as isoprene in life cycle assessments performed on potential biofuel feedstocks.

  2. A multi-biomarker risk assessment of the impact of brominated flame retardant-decabromodiphenyl ether (BDE209) on the antioxidant system of earthworm Eisenia fetida.

    Science.gov (United States)

    Zhang, Wei; Liu, Kou; Chen, Lin; Chen, Lei; Lin, Kuangfei; Fu, Rongbing

    2014-07-01

    Decabromodiphenyl ether (BDE209) is the major contaminant at e-waste recycling sites (EWRSs), and its potential toxicological effects on terrestrial organisms have received extensive attention. However, the impacts of BDE209 on the antioxidant defense system in terrestrial organisms remain vague. Therefore, indoor incubation tests were performed systematically on control and contaminated soil samples to determine the effects of BDE209 on the antioxidant system of earthworm Eisenia fetida. The results showed that compared to the controls, superoxide dismutase (SOD) activities in all treated groups were elevated significantly after 21 and 28 days exposure; catalase (CAT) activities were much higher in all tests during the entire exposure period; peroxidase (POD) and glutathione-s-transferase (GST) activities generally decreased and indicated contrary response trend; the total antioxidant capacity (T-AOC) after exposure to low level of BDE209 (1 mg kg(-1)) was induced, whereas at 10 and 100 mg kg(-1) concentrations it showed suppression status; electron paramagnetic resonance (EPR) spectra suggested that hydroxyl radicals (OH) in earthworms were significantly induced by BDE209; the changes in malondialdehyde (MDA) contents suggested that reactive oxygen species (ROS) might lead to cellular lipid peroxidation in earthworms. The results of these observations suggested that severe oxidative stress occurred in E. fetida, and it may play an important role in inducing the BDE209 toxicity to earthworms. PMID:25016100

  3. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    OpenAIRE

    Venot Olivia; Fray Nicolas; Bénilan Yves; Gazeau Marie-Claire; Hébrard Eric; Larcher Gwenaelle; Schwell Martin; Dobrijevic Michel; Selsis Franck

    2014-01-01

    Ultraviolet (UV) absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are se...

  4. Impact of biomass burning on ocean water quality in Southeast Asia through atmospheric deposition: eutrophication modeling

    OpenAIRE

    P. Sundarambal; P. Tkalich; Balasubramanian, R

    2010-01-01

    Atmospheric deposition of nutrients (N and P species) can intensify anthropogenic eutrophication of coastal waters. It was found that the atmospheric wet and dry depositions of nutrients was remarkable in the Southeast Asian region during the course of smoke haze events, as discussed in a companion paper on field observations (Sundarambal et al., 2010b). The importance of atmospheric deposition of nutrients in terms of their biological responses in the coastal waters of the ...

  5. Reassessing the impacts and the atmospheric circulation of the large storms over Portugal

    Science.gov (United States)

    Varino, F.; Trigo, R. M.; Zêzere, J. L.

    2012-04-01

    The present work was made possible after the recently development of a database of flooding and landslide events that occurred in Portugal during the 20 century. This database was collected through careful analysis of most available daily Portuguese newspapers at the time, namely "Diário de Noticias" and "Século" describing the consequences of important hydro-geological hazards during the 20 century. Therefore it is possible to evaluate the impact of these events through relatively detailed reports of the most affected places, including; number of deaths, dislodged and evacuated people, and even involved rescue entities or costs. On the other hand, the analysis of meteorological conditions for these events was made possible through the recent development of the 20 Century Reanalysis dataset from National Oceanic & Atmospheric Administration (NOAA) (Compo et al., 2011), that covers the entire period in study. This long-term database allows re-evaluating the atmospheric conditions not only at the surface but also at several levels of the atmosphere, enabling a new approach to the studied events. Moreover, the new reanalysis is also more extended in time, with available data from 1871 until 2008 which makes it possible to represent and study the weather events before 1948 with a new perspective. In this work it is analysed in detail the most important and devastating storm that took place since 1871, including the strongest sequence of storms ever observed in early December 1876 that lead to catastrophic floods in river Guadiana and Tagus. Other extreme events episodes that took place throughout the 20 century and never studied before are also analysed (albeit in less detail), namely on the 22 December 1909, 20 November 1937, 23 January and 1 February 1941, 19 November 1945, 2 January 1962 and 25 November 1967 the deadliest flood ever that occurred in Portugal. For each event it was computed the sequence of 6 hourly weather fields of precipitation rate and mean sea

  6. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Precipitation Forecasting

    Science.gov (United States)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles in clear and cloudy regions with accuracy which approaches that of radiosondes. The purpose of this paper is to describe an approach to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research WRF (ARW) model using WRF-Var. Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in clear and partly cloudy regions, and uncontaminated portions of retrievals above clouds in overcast regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts resulting from improved thermodynamic fields. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  7. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Weather Forecasting

    Science.gov (United States)

    Chou, Shih-Hung; Zavodsky, Bradley T.; Jedlovee, Gary J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimension variational (3DVAR) analysis component (WRF-Var). Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in both clear and partly cloudy regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts due to instability added in the forecast soundings by the AIRS profiles. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  8. Characteristics of re-suspended road dust and its impact on the atmospheric environment in Beijing

    Science.gov (United States)

    Han, Lihui; Zhuang, Guoshun; Cheng, Shuiyuan; Wang, Ying; Li, Juan

    A sampling campaign of re-suspended road dust samples from 53 sites that could cover basically the entire Beijing, soil samples from the source regions of dust storm in August 2003, and aerosol samples from three representative sites in Beijing from December 2001 to September 2003, was carried out to investigate the characteristics of re-suspended road dust and its impact on the atmospheric environment. Ca, S, Cu, Zn, Ni, Pb, and Cd were far higher than its crustal abundances and Ca 2+, SO 42-, Cl -, K +, Na +, NO 3- were major ions in re-suspended road dust. Al, Ti, Sc, Co, and Mg in re-suspended road dust were mainly originated from crustal source, while Cu, Zn, Ni, and Pb were mainly derived from traffic emissions and coal burning, and Fe, Mn, and Cd were mainly from industrial emissions, coal combustion and oil burning. Ca 2+ and SO 42- mainly came from construction activities, construction materials and secondary gas-particle conversions, Cl - and Na + were derived from industrial wastewater disposal and chemical industrial emissions, and NO 3- and K + were from vehicle emissions, photochemical reactions of NO X, biomass and vegetable burning. The contribution of mineral aerosol from inside Beijing to the total mineral aerosols was ˜30% in spring of 2002, ˜70% in summer of 2002, ˜80% in autumn of 2003, ˜20% in PM 10 and ˜50% in PM 2.5, in winter of 2002. The pollution levels of the major pollution species, Ca, S, Cu, Zn, Ni, Pb, Fe, Mn, and Cd in re-suspended road dust reached ˜76%, ˜87%, ˜75%, ˜80%, ˜82%, ˜90%, ˜45%, ˜51%, and ˜94%, respectively. Re-suspended road dust from the traffic and construction activities was one of the major sources of pollution aerosols in Beijing.

  9. The impact of Southern Ocean residual upwelling on atmospheric CO2 on centennial and millennial timescales

    Science.gov (United States)

    Lauderdale, Jonathan M.; Williams, Richard G.; Munday, David R.; Marshall, David P.

    2016-05-01

    This study examines the variability of the power dissipation index (PDI) for different regions of the East Asia region during the period 1960-2013. The annual PDI (APDI) in the region is calculated as the sum of the PDI, defined as the cube of the maximum sustained wind speed at landfall of each tropical cyclone (TC) making landfall at that region. Upward and downward trends in APDI are found in the northern and southern parts of East Asia respectively, suggesting a possible northward shift in TC landfall locations. Interdecadal variations of the APDI can also be found in some regions. The APDI in various regions show a close relation with the PDI distribution over the western North Pacific (WNP) with three characteristic patterns. The ENSO and basin-wide mode represents the PDI patterns associated with ENSO events and the overall PDI over the WNP. The east-west dipole mode and the north-south dipole mode denote the east-west and north-south shifts of PDI respectively. Based on the steering flow (average winds within the 850-300 hPa layer) near the East Asian coast, a three-cell model for TC landfall in East Asia is proposed, which corresponds to three major modes of the atmospheric circulation in the WNP. Each of these modes shows an anomalous circulation located east of Taiwan, east of Japan and the South China Sea, respectively and each of which has a significant impact on the APDI in some regions along the coast of East Asia. A northward shift in the APDI along the East Asian coast is identified in the period 1997-2013 as a result of the change in steering flow pattern, northward shift in TC genesis location and weaker vertical wind shear over the ocean near the coastal areas.

  10. Blooming of Irganox 3114® antioxidant onto a medical grade elastomer. Impact of the recrystallization conditions on the antioxidant polymorphism, on the film wettability and on the antioxidant leachability.

    Science.gov (United States)

    Saunier, J; Mazel, V; Aymes-Chodur, C; Yagoubi, N

    2012-11-01

    Studying the blooming and recrystallization of additives onto the surface of polymer medical devices is of a great interest because it can affect the biocompatibility of the material. The polymorphism of a phenolic antioxidant (Irganox 3114(®)) used as an additive in medical devices and pharmaceutical packaging was studied: two different polymorphs were characterized by differential scanning measurements, FTIR and X-ray diffraction analyses. Then, the behavior of the additive in medical grade polyurethane films was described: a recrystallization into the stable polymorphic form was observed onto the polymer surface after annealing at different temperatures. The morphology observed depends not only on the additive/polymer ratio but also on the whole amount of additive in the polymer film. Depending on the recrystallization morphology, the wettability with water could be lowered and the leachability of the additives into aqueous media could be favored. PMID:22884835

  11. Blooming of Irganox 3114® antioxidant onto a medical grade elastomer. Impact of the recrystallization conditions on the antioxidant polymorphism, on the film wettability and on the antioxidant leachability.

    Science.gov (United States)

    Saunier, J; Mazel, V; Aymes-Chodur, C; Yagoubi, N

    2012-11-01

    Studying the blooming and recrystallization of additives onto the surface of polymer medical devices is of a great interest because it can affect the biocompatibility of the material. The polymorphism of a phenolic antioxidant (Irganox 3114(®)) used as an additive in medical devices and pharmaceutical packaging was studied: two different polymorphs were characterized by differential scanning measurements, FTIR and X-ray diffraction analyses. Then, the behavior of the additive in medical grade polyurethane films was described: a recrystallization into the stable polymorphic form was observed onto the polymer surface after annealing at different temperatures. The morphology observed depends not only on the additive/polymer ratio but also on the whole amount of additive in the polymer film. Depending on the recrystallization morphology, the wettability with water could be lowered and the leachability of the additives into aqueous media could be favored.

  12. Gamma irradiation of air-dried olive leaves: Effective decontamination and impact on the antioxidative properties and on phenolic compounds.

    Science.gov (United States)

    Aouidi, Fathia; Ayari, Samia; Ferhi, Hana; Roussos, Sevastianos; Hamdi, Moktar

    2011-08-01

    Olive leaves are commercialized for their antioxidative value due to their valuable phenolic compounds. The present study aimed to evaluate the effect of gamma irradiation on microbial load, on antioxidative properties and on phenolic compounds of air-dried olive leaves. Irradiation was applied up to 25kGy (5kGy intervals) to powdered and intact samples. Total aerobic bacteria, yeast and mold, and lactic acid bacteria were counted after gamma irradiation. Decontamination was obtained at 20kGy. The radioresistance of microbial population was high with D10 values between 9.74 and 25.12kGy. Besides, gamma irradiation up to 25kGy was found to maintain the antioxidant capacity, molecular mass distribution of polyphenolics, total phenolics, ortho-diphenols, flavonoids, oleuropein, verbascoside and rutin contents. To conclude, the improvement of the microbial quality of air-dried olive leaves, without affecting phenolic composition and antioxidative properties, can be successively achieved by the application of gamma irradiation treatment. PMID:25214102

  13. The impact of forest canopy structure on simulations of atmosphere-biosphere NO

    NARCIS (Netherlands)

    Firanj, Ana; Lalic, Branislava; Ganzeveld, Laurens; Podrascanin, Zorica

    2015-01-01

    The concentrations and fluxes of reactive nitrogen species in the land-atmosphere system are controlled by complex interactions between emissions, turbulent transfer, dry deposition and chemical transformations. The forest canopy can significantly affect turbulent fluxes between the atmosphere, t

  14. Biogeochemical context impacts seawater pH changes resulting from atmospheric sulfur and nitrogen deposition

    NARCIS (Netherlands)

    Hagens, M.; Hunter, K.A.; Liss, P.S.; Middelburg, J.J.

    2014-01-01

    Seawater acidification can be induced both by absorption of atmospheric carbon dioxide (CO2) and by atmospheric deposition of sulfur and nitrogen oxides and ammonia. Their relative significance, interplay, and dependency on water column biogeochemistry are not well understood. Using a simple biogeoc

  15. Observations of Recent Arctic Sea Ice Volume Loss and Its Impact on Ocean-Atmosphere Energy Exchange and Ice Production

    Science.gov (United States)

    Kurtz, N. T.; Markus, T.; Farrell, S. L.; Worthen, D. L.; Boisvert, L. N.

    2011-01-01

    Using recently developed techniques we estimate snow and sea ice thickness distributions for the Arctic basin through the combination of freeboard data from the Ice, Cloud, and land Elevation Satellite (ICESat) and a snow depth model. These data are used with meteorological data and a thermodynamic sea ice model to calculate ocean-atmosphere heat exchange and ice volume production during the 2003-2008 fall and winter seasons. The calculated heat fluxes and ice growth rates are in agreement with previous observations over multiyear ice. In this study, we calculate heat fluxes and ice growth rates for the full distribution of ice thicknesses covering the Arctic basin and determine the impact of ice thickness change on the calculated values. Thinning of the sea ice is observed which greatly increases the 2005-2007 fall period ocean-atmosphere heat fluxes compared to those observed in 2003. Although there was also a decline in sea ice thickness for the winter periods, the winter time heat flux was found to be less impacted by the observed changes in ice thickness. A large increase in the net Arctic ocean-atmosphere heat output is also observed in the fall periods due to changes in the areal coverage of sea ice. The anomalously low sea ice coverage in 2007 led to a net ocean-atmosphere heat output approximately 3 times greater than was observed in previous years and suggests that sea ice losses are now playing a role in increasing surface air temperatures in the Arctic.

  16. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    CERN Document Server

    Venot, Olivia; Bénilan, Yves; Gazeau, Marie-Claire; Hébrard, Eric; Larcher, Gwenaelle; Schwell, Martin; Dobrijevic, Michel; Selsis, Franck

    2015-01-01

    Ultraviolet (UV) absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm....

  17. Impact of aircraft exhaust on the atmosphere. Box model studies and 3-D mesoscale numerical case studies of seasonal differences

    Energy Technology Data Exchange (ETDEWEB)

    Petry, H.; Ebel, A.; Franzkowiak, V.; Hendricks, J.; Lippert, E.; Moellhoff, M. [Koeln Univ. (Germany). Inst. fuer Geophysik und Meteorologie

    1997-12-31

    The impact of aircraft emissions released in the tropopause region on atmospheric trace gases as O{sub 3} or HNO{sub 3} is investigated by means of model studies. Special emphasis is drawn on seasonal effects. A box model is applied as well as a 3-D mesoscale chemistry transport model. These model studies show that the impact of aircraft emissions on ozone in the tropopause region is much stronger in summer than in late autumn with a difference of one order of magnitude. (author) 14 refs.

  18. Tropical forests and the global carbon cycle: impacts of atmospheric carbon dioxide, climate change and rate of deforestation.

    OpenAIRE

    Cramer, Wolfgang; Bondeau, Alberte; Schaphoff, Sibyll; Lucht, Wolfgang; Smith, Benjamin; Sitch, Stephen

    2004-01-01

    The remaining carbon stocks in wet tropical forests are currently at risk because of anthropogenic deforestation, but also because of the possibility of release driven by climate change. To identify the relative roles of CO2 increase, changing temperature and rainfall, and deforestation in the future, and the magnitude of their impact on atmospheric CO2 concentrations, we have applied a dynamic global vegetation model, using multiple scenarios of tropical deforestation (extrapolated from two ...

  19. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 1: Land transport and shipping

    OpenAIRE

    Righi, M; Hendricks, J.; Sausen, R.

    2014-01-01

    Using the EMAC global climate-chemistry model coupled to the aerosol module MADE, we simulate the impact of land transport and shipping emissions on global atmospheric aerosol and climate in 2030. Future emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs) designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare the resulting 2030 land-transport- and ...

  20. The global impact of the transport sectors on atmospheric aerosol in 2030 - Part 1: Land transport and shipping

    OpenAIRE

    Righi, Mattia; Hendricks, Johannes; Sausen, Robert

    2015-01-01

    Using the EMAC global climate-chemistry model coupled to the aerosol module MADE, we simulate the impact of land transport and shipping emissions on global atmospheric aerosol and climate in 2030. Future emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs) designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare the resulting 2030 land-transport- and shipping-induced aerosol concent...

  1. Land cover change impacts on atmospheric chemistry: simulating projected large-scale tree mortality in the United States

    OpenAIRE

    Geddes, Jeffrey A.; Heald, Colette L.; Martin, Randall V.; Silva, Sam James

    2016-01-01

    Land use and land cover changes impact climate and air quality by altering the exchange of trace gases between the Earth's surface and atmosphere. Large-scale tree mortality that is projected to occur across the United States as a result of insect and disease may therefore have unexplored consequences for tropospheric chemistry. We develop a land use module for the GEOS-Chem global chemical transport model to facilitate simulations involving changes to the land surface, and to improve consist...

  2. Impact of Different Aerosols on the Evolution of the Atmospheric Boundary Layer

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The present work analyzes the effect of aerosols on the evolution of the atmospheric boundary layer (ABL) over Shangdianzi in Beijing.A one-dimensional ABL model and a radiative transfer scheme are incorporated to develop the structure of the ABL.The diurnal variation of the atmospheric radiative budget,atmospheric heating rate,sensible and latent heat fluxes,surface and the 2 m air temperatures as well as the ABL height,and its perturbations due to the aerosols with different single-scattering albedo (SSA) are studied by comparing the aerosol-laden atmosphere to the clean atmosphere.The results show that the absorbing aerosols cause less reduction in surface evaporation relative to that by scatting aerosols,and both surface temperature and 2 m temperature decrease from the clean atmosphere to the aerosol-laden atmosphere.The greater the aerosol absorption,the more stable the surface layer.After 12:00 am,the 2 m temperature increases for strong absorption aerosols.In the meantime,there is a slight decrease in the 2 m temperature for purely scattering aerosols due to radiative cooling.The purely scattering aerosols decrease the ABL temperature and enhance the capping inversion,further reducing the ABL height.

  3. he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study

    Energy Technology Data Exchange (ETDEWEB)

    Keene, William C. [University of Virginia; Long, Michael S. [University of Virginia

    2013-05-20

    of marine aerosol production on the microphysical properties of aerosol populations and clouds over the ocean and the corresponding direct and indirect effects on radiative transfer; (2) atmospheric burdens of reactive halogen species and their impacts on O3, NOx, OH, DMS, and particulate non-sea-salt SO42-; and (3) the global production and influences of marine-derived particulate organic carbon. The model reproduced major characteristics of the marine aerosol system and demonstrated the potential sensitivity of global, decadal-scale climate metrics to multiphase marine-derived components of Earth's troposphere. Due to the combined computational burden of the coupled system, the currently available computational resources were the limiting factor preventing the adequate statistical analysis of the overall impact that multiphase chemistry might have on climate-scale radiative transfer and climate.

  4. Hydrodynamical model atmospheres: Their impact on stellar spectroscopy and asteroseismology of late-type stars

    CERN Document Server

    Ludwig, Hans-G

    2016-01-01

    Hydrodynamical, i.e. multi-dimensional and time-dependent, model atmospheres of late-type stars have reached a high level of realism. They are commonly applied in high-fidelity work on stellar abundances but also allow the study of processes that are not modelled in standard, one-dimensional hydrostatic model atmospheres. Here, we discuss two observational aspects that emerge from such processes, the photometric granulation background and the spectroscopic microturbulence. We use CO5BOLD hydrodynamical model atmospheres to characterize the total granular brightness fluctuations and characteristic time scale for FGK stars. Emphasis is put on the diagnostic potential of the granulation background for constraining the fundamental atmospheric parameters. We find a clear metallicity dependence of the granulation background. The comparison between the model predictions and available observational constraints at solar metallicity shows significant differences, that need further clarification. Concerning microturbule...

  5. Characterization of a boreal convective boundary layer and its impact on atmospheric chemistry during HUMPPA-COPEC-2010

    Directory of Open Access Journals (Sweden)

    H. G. Ouwersloot

    2012-06-01

    Full Text Available We studied the atmospheric boundary layer (ABL dynamics and the impact on atmospheric chemistry during the HUMPPA-COPEC-2010 campaign. We used vertical profiles of potential temperature and specific moisture, obtained from 132 radio soundings, to determine the main boundary layer characteristics during the campaign. We propose a classification according to several main ABL prototypes. Further, we performed a case study of a single day characterized as a convective boundary layer to analyse the influence of the dynamics on the chemical evolution of the ABL, using a systematic analysis that can easily be extended to other periods during HUMPPA-COPEC-2010. We used a mixed layer model, initialized and constrained by observations. In particular, we investigated the role of large scale atmospheric dynamics (subsidence and advection on the ABL development and the evolution of chemical species concentrations. We find that, if the large scale forcings are taken into account, the ABL dynamics are represented satisfactorily. Subsequently, we studied the impact of mixing with a residual layer aloft during the morning transition on atmospheric chemistry. The time evolution of NOx and O3 concentrations, including morning peaks, can be explained and accurately simulated by incorporating the transition of the ABL dynamics from night to day. We demonstrate the importance of the ABL height evolution for the representation of atmospheric chemistry. Our findings underscore the need to couple the dynamics and chemistry at different spatial scales (from turbulence to mesoscale in chemistry-transport models and in the interpretation of observational data.

  6. Evaluation of the Impact of Atmospheric Infrared Sounder (AIRS) Radiance and Profile Data Assimilation in Partly Cloudy Regions

    Science.gov (United States)

    Zavodsky, Bradley; Srikishen, Jayanthi; Jedlovec, Gary

    2013-01-01

    Improvements to global and regional numerical weather prediction have been demonstrated through assimilation of data from NASA s Atmospheric Infrared Sounder (AIRS). Current operational data assimilation systems use AIRS radiances, but impact on regional forecasts has been much smaller than for global forecasts. Retrieved profiles from AIRS contain much of the information that is contained in the radiances and may be able to reveal reasons for this reduced impact. Assimilating AIRS retrieved profiles in an identical analysis configuration to the radiances, tracking the quantity and quality of the assimilated data in each technique, and examining analysis increments and forecast impact from each data type can yield clues as to the reasons for the reduced impact. By doing this with regional scale models individual synoptic features (and the impact of AIRS on these features) can be more easily tracked. This project examines the assimilation of hyperspectral sounder data used in operational numerical weather prediction by comparing operational techniques used for AIRS radiances and research techniques used for AIRS retrieved profiles. Parallel versions of a configuration of the Weather Research and Forecasting (WRF) model with Gridpoint Statistical Interpolation (GSI) are run to examine the impact AIRS radiances and retrieved profiles. Statistical evaluation of 6 weeks of forecast runs will be compared along with preliminary results of in-depth investigations for select case comparing the analysis increments in partly cloudy regions and short-term forecast impacts.

  7. Impact of rocket exhaust plumes on atmospheric composition and climate – an overview

    OpenAIRE

    Voigt, Christiane; Schumann, Ulrich; Graf, Kaspar; Gottschaldt, Klaus-Dirk

    2013-01-01

    Rockets are the only direct anthropogenic emission sources into the upper atmosphere. Gaseous rocket emissions include CO, N2, H2, H2O, and CO2, while solid rocket motors (SRM) additionally inject significant amounts of aluminum oxide (Al2O3) particles and gaseous chlorine species into the atmosphere. These emissions strongly perturb local at- mospheric trace gas and aerosol distributions. Here, the previous aircraft measurements in various rocket exhaust plumes including several large spa...

  8. Impact of uncertainties in atmospheric mixing on simulated UTLS composition and related radiative effects

    OpenAIRE

    Riese, Martin; Ploeger, F; Rap, A.; B. Vogel; P. Konopka; Dameris, Martin; Forster, P

    2012-01-01

    The upper troposphere/lower stratosphere (UTLS) region plays an important role in the climate system. Changes in the structure and chemical composition of this region result in particularly large changes in radiative forcings of the atmosphere. Quantifying the processes that control UTLS composition (e.g., stratosphere-troposphere exchange) therefore represents a crucial task. We assess the influence of uncertainties in the atmospheric mixing strength on global UTLS distributions of greenh...

  9. Impact of acid atmospheric deposition on soils: Field monitoring and aluminium chemistry.

    OpenAIRE

    Mulder, J.

    1988-01-01

    The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions were obtained from intensive monitoring programmes conducted at a number of sites in northwestern Europe and North-America. Specific hypotheses were tested in laboratory experiments.Atmospheric acid inputs do...

  10. The impact of vibrational Raman scattering of air on DOAS measurements of atmospheric trace gases

    OpenAIRE

    J. Lampel; Frieß, U.; Platt, U.

    2015-01-01

    In remote sensing applications, such as differential optical absorption spectroscopy (DOAS), atmospheric scattering processes need to be considered. After inelastic scattering on N2 and O2 molecules, the scattered photons occur as additional intensity at a different wavelength, effectively leading to "filling-in" of both solar Fraunhofer lines and absorptions of atmospheric constituents, if the inelastic scattering happens after the absorption. Measured spectra in p...

  11. Impact of aerosols present in Titan's atmosphere on the CASSINI radar experiment

    OpenAIRE

    Rodriguez, S; Paillou, Philippe; Dobrijevic, M.; Ruffié, G.; Coll, P.; Bernard, J. M.; Encrenaz, P.

    2003-01-01

    International audience Simulations of Titan's atmospheric transmission and surface reflectivity have been developed in order to estimate how Titan's atmosphere and surface properties could affect performances of the Cassini radar experiment. In this paper we present a selection of models for Titan's haze, vertical rain distribution, and surface composition implemented in our simulations. We collected dielectric constant values for the Cassini radar wavelength ($\\sim 2.2$ cm) for materials ...

  12. The impact of vibrational Raman scattering of air on DOAS measurements of atmospheric trace gases

    OpenAIRE

    Lampel, J; Frieß, U.; U. Platt

    2015-01-01

    In remote sensing applications, such as differential optical absorption spectroscopy (DOAS), atmospheric scattering processes need to be considered. After inelastic scattering on N2 and O2 molecules, the scattered photons occur as additional intensity at a different wavelength, effectively leading to filling-in of both solar Fraunhofer lines and absorptions of atmospheric constituents. Measured spectra in passive DOAS applications are typically corrected for rotationa...

  13. Impact of cosmic rays and solar energetic particles on the Earth’s ionosphere and atmosphere

    OpenAIRE

    Mateev Lachezar; Lastovicka Jan; Kudela Karel; Asenovski Simeon; Velinov Peter I.Y.; Mishev Alexander; Tonev Peter

    2013-01-01

    A brief review of the study during COST Action ES0803 of effects due to cosmic rays (CR) and solar energetic particles (SEP) in the ionosphere and atmosphere is presented. Models CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere) and application of CORSIKA (COsmic Ray SImulations for KAscade) code are considered. They are capable to compute the cosmic ray ionization profiles at a given location, time, solar and geomagnetic activity. Intercomparison of the models, as well as c...

  14. Enhanced solubility and ecological impact of atmospheric phosphorus deposition upon extended seawater exposure.

    Science.gov (United States)

    Mackey, Katherine R M; Roberts, Kathryn; Lomas, Michael W; Saito, Mak A; Post, Anton F; Paytan, Adina

    2012-10-01

    Atmospheric P solubility affects the amount of P available for phytoplankton in the surface ocean, yet our understanding of the timing and extent of atmospheric P solubility is based on short-term leaching experiments where conditions may differ substantially from the surface ocean. We conducted longer- term dissolution experiments of atmospheric aerosols in filtered seawater, and found up to 9-fold greater dissolution of P after 72 h compared to instantaneous leaching. Samples rich in anthropogenic materials released dissolved inorganic P (DIP) faster than mineral dust. To gauge the effect of biota on the fate of atmospheric P, we conducted field incubations with aerosol samples collected in the Sargasso Sea and Red Sea. In the Sargasso Sea phytoplankton were not P limited, and biological activity enhanced DIP release from aerosols, and aerosols induced biological mineralization of dissolved organic P in seawater, leading to DIP accumulation. However, in the Red Sea where phytoplankton were colimited by P and N, soluble P was rapidly consumed by phytoplankton following aerosol enrichment. Our results suggest that atmospheric P dissolution could continue over multiple days once reaching the surface ocean, and that previous estimates of atmospheric P deposition may underestimate the contribution from this source.

  15. Impact of atmospheric uncertainties and viscous interaction effects on the performance of aeroassisted orbital transfer vehicles

    Science.gov (United States)

    Talay, T. A.; White, N. H.; Naftel, J. C.

    1984-01-01

    Simulations of aerobraking trajectories of aeroassisted orbital transfer vehicles (AOTV's) returning from geosynchronous orbit were analyzed to examine the effects of high-altitude viscous interactions and off-nominal atmospheres on AOTV return weight, heating, and loads performance. Viscous interaction effects encountered at high altitudes had little detrimental effect on the return weight capabilities for AOTV's representing a range of lift/drag ratios. Most of the AOTV return weight increase over an all-propulsive OTV occurred for a low lift/drag ratio. Smaller increases in return weight were observed for higher lift/drag ratios, at the expense of significantly higher heating and aerodynamic loads. Off-nominal atmospheres based on Shuttle-derived data and multipliers on a U.S. Standard Atmosphere were considered. AOTV's intended for entry under standard atmospheric conditions either deorbited during the pass through the off-nominal atmospheres or missed the target phasing orbit by wide margins. The AOTV's could successfully negotiate these atmospheres when new bank-angle histories were implemented with little loss and sometimes with a gain in return weight.

  16. Cryopreservation of ram semen with antioxidant supplemented soybean lecithin-based extenders and impacts on incubation resilience.

    Science.gov (United States)

    Toker, M Berk; Alcay, Selim; Gokce, Elif; Ustuner, Burcu

    2016-06-01

    The scope of this study was investigation the affects of various antioxidants on 1% soybean lecithin-based semen extenders for ram semen cryopreservation. Ejaculates, collected via electrically stimulated ejaculation, that have a thick consistency, rapid wave motion (3-5 on a 0-5 scale) and >75% initial motility were pooled. The pooled samples were split into four equal aliquots as 5 mM Methionine, 5 mM Cysteamine, 1 mM Cysteine and a sample of antioxidant-free control group. Each sample group was diluted to a ratio of 1/5 (semen/extender, v/v) as final concentration and two step dilution method was used for cryopreservation. Extender groups were assessed for sperm motility, plasma membrane functional integrity using hypoosmotic swelling test (HOST), damaged acrosome using FITC-Pisum sativum agglutinin (PSA-FITC) and DNA integrity using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Semen samples also incubated for 6 h in humidified air with 5% CO2 at 39 °C to evaluate post-thaw incubation resilience of semen characteristics. The results showed that freezing and thawing procedures had negative effects on motility (P < 0.05), plasma membrane integrity (P < 0.05) and acrosomal integrity (P < 0.05). After 6 h of incubation time, the Cysteine supplemented extender group yielded significantly higher results than other extender groups in terms of spermatological parameters. Furthermore MDA levels in the antioxidant groups were lower than control group (P < 0.05). Nevertheless, there were no significant differences among antioxidant groups.

  17. Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status

    OpenAIRE

    Babaknia Ari; DiSilvestro Robert A; Brown Erin C; Devor Steven T

    2004-01-01

    Abstract Background Although soy protein may have many health benefits derived from its associated antioxidants, many male exercisers avoid soy protein. This is due partly to a popular, but untested notion that in males, soy is inferior to whey in promoting muscle weight gain. This study provided a direct comparison between a soy product and a whey product. Methods Lean body mass gain was examined in males from a university weight training class given daily servings of micronutrient-fortified...

  18. Iron-ascorbate-mediated lipid peroxidation causes epigenetic changes in the antioxidant defense in intestinal epithelial cells: impact on inflammation.

    Directory of Open Access Journals (Sweden)

    Sabrina Yara

    Full Text Available INTRODUCTION: The gastrointestinal tract is frequently exposed to noxious stimuli that may cause oxidative stress, inflammation and injury. Intraluminal pro-oxidants from ingested nutrients especially iron salts and ascorbic acid frequently consumed together, can lead to catalytic formation of oxygen-derived free radicals that ultimately overwhelm the cellular antioxidant defense and lead to cell damage. HYPOTHESIS: Since the mechanisms remain sketchy, efforts have been exerted to evaluate the role of epigenetics in modulating components of endogenous enzymatic antioxidants in the intestine. To this end, Caco-2/15 cells were exposed to the iron-ascorbate oxygen radical-generating system. RESULTS: Fe/Asc induced a significant increase in lipid peroxidation as reflected by the elevated formation of malondialdehyde along with the alteration of antioxidant defense as evidenced by raised superoxide dismutase 2 (SOD2 and diminished glutathione peroxidase (GPx activities and genes. Consequently, there was an up-regulation of inflammatory processes illustrated by the activation of NF-κB transcription factor, the higher production of interleukin-6 and cycloxygenase-2 as well as the decrease of IκB. Assessment of promoter's methylation revealed decreased levels for SOD2 and increased degree for GPx2. On the other hand, pre-incubation of Caco-2/15 cells with 5-Aza-2'-deoxycytidine, a demethylating agent, or Trolox antioxidant normalized the activities of SOD2 and GPx, reduced lipid peroxidation and prevented inflammation. CONCLUSION: Redox and inflammatory modifications in response to Fe/Asc -mediated lipid peroxidation may implicate epigenetic methylation.

  19. Impact of organic and inorganic fertilizers application on the phytochemical and antioxidant activity of Kacip Fatimah (Labisia pumila Benth).

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Karimi, Ehsan; Ghasemzadeh, Ali

    2013-09-05

    A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah) in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P₂O₅:10% K₂O) and inorganic fertilizer (NPK green; 15% N, 15% P₂O₅, 15% K₂O)] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic fertilizer enhanced the production of total phenolics, flavonoids, ascorbic acid, saponin and gluthathione content in L. pumila, compared to the use of inorganic fertilizer. The nitrate content was also reduced under organic fertilization. The application of nitrogen at 90 kg N/ha improved the production of secondary metabolites in Labisia pumila. Higher rates in excess of 90 kg N/ha reduced the level of secondary metabolites and antioxidant activity of this herb. The DPPH and FRAP activity was also highest at 90 kg N/ha. The results indicated that the use of chicken dung can enhance the production of secondary metabolites and improve antioxidant activity of this herb.

  20. Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status

    Directory of Open Access Journals (Sweden)

    Babaknia Ari

    2004-12-01

    Full Text Available Abstract Background Although soy protein may have many health benefits derived from its associated antioxidants, many male exercisers avoid soy protein. This is due partly to a popular, but untested notion that in males, soy is inferior to whey in promoting muscle weight gain. This study provided a direct comparison between a soy product and a whey product. Methods Lean body mass gain was examined in males from a university weight training class given daily servings of micronutrient-fortified protein bars containing soy or whey protein (33 g protein/day, 9 weeks, n = 9 for each protein treatment group. Training used workouts with fairly low repetition numbers per set. A control group from the class (N = 9 did the training, but did not consume either type protein bar. Results Both the soy and whey treatment groups showed a gain in lean body mass, but the training-only group did not. The whey and training only groups, but not the soy group, showed a potentially deleterious post-training effect on two antioxidant-related related parameters. Conclusions Soy and whey protein bar products both promoted exercise training-induced lean body mass gain, but the soy had the added benefit of preserving two aspects of antioxidant function.

  1. Impact of Organic and Inorganic Fertilizers Application on the Phytochemical and Antioxidant Activity of Kacip Fatimah (Labisia pumila Benth

    Directory of Open Access Journals (Sweden)

    Ehsan Karimi

    2013-09-01

    Full Text Available A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P2O5:10% K2O and inorganic fertilizer (NPK green; 15% N, 15% P2O5, 15% K2O] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic fertilizer enhanced the production of total phenolics, flavonoids, ascorbic acid, saponin and gluthathione content in L. pumila, compared to the use of inorganic fertilizer. The nitrate content was also reduced under organic fertilization. The application of nitrogen at 90 kg N/ha improved the production of secondary metabolites in Labisia pumila. Higher rates in excess of 90 kg N/ha reduced the level of secondary metabolites and antioxidant activity of this herb. The DPPH and FRAP activity was also highest at 90 kg N/ha. The results indicated that the use of chicken dung can enhance the production of secondary metabolites and improve antioxidant activity of this herb.

  2. Impact of organic and inorganic fertilizers application on the phytochemical and antioxidant activity of Kacip Fatimah (Labisia pumila Benth).

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Karimi, Ehsan; Ghasemzadeh, Ali

    2013-01-01

    A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah) in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P₂O₅:10% K₂O) and inorganic fertilizer (NPK green; 15% N, 15% P₂O₅, 15% K₂O)] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic fertilizer enhanced the production of total phenolics, flavonoids, ascorbic acid, saponin and gluthathione content in L. pumila, compared to the use of inorganic fertilizer. The nitrate content was also reduced under organic fertilization. The application of nitrogen at 90 kg N/ha improved the production of secondary metabolites in Labisia pumila. Higher rates in excess of 90 kg N/ha reduced the level of secondary metabolites and antioxidant activity of this herb. The DPPH and FRAP activity was also highest at 90 kg N/ha. The results indicated that the use of chicken dung can enhance the production of secondary metabolites and improve antioxidant activity of this herb. PMID:24013410

  3. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  4. PHOTOPROTECTIVE ANTIOXIDANT PHYTOCHEMICALS

    Directory of Open Access Journals (Sweden)

    Sharada L Deore

    2012-07-01

    Full Text Available Many ayurvedic natural products have properties to rejuvenate and protect the skin from environmental pollution, chemicals, atmospheric temperature fluctuation, UVA and UVB radiation, wrinkling, hyperpigmentation (excessive tanning and inflammation. The present review focuses on properties and mechanism of action of photoprotective antioxidant phytoconstituents obtained from ayurvedic plants such as flavonoids, carotenoids, phenolics which can be useful in development of effective photoprotective herbal cosmetic formulation.

  5. Exploring the climatic impact of the continental vegetation on the Mezosoic atmospheric CO2 and climate history

    Directory of Open Access Journals (Sweden)

    N. Bouttes

    2008-09-01

    Full Text Available In this contribution, we continue our exploration of the factors defining the Mesozoic climatic history. We improve the Earth system model GEOCLIM designed for long term climate and geochemical reconstructions by adding the explicit calculation of the biome dynamics using the LPJ model. The coupled GEOCLIM-LPJ model thus allows the simultaneous calculation of the climate with a 2-D spatial resolution, the coeval atmospheric CO2, and the continental biome distribution. We found that accounting for the climatic role of the continental vegetation dynamics (albedo change, water cycle and surface roughness modulations strongly affects the reconstructed geological climate. Indeed the calculated partial pressure of atmospheric CO2 over the Mesozoic is twice the value calculated when assuming a uniform constant vegetation. This increase in CO2 is triggered by a global cooling of the continents, itself triggered by a general increase in continental albedo owing to the development of desertic surfaces. This cooling reduces the CO2 consumption through silicate weathering, and hence results in a compensating increase in the atmospheric CO2 pressure. This study demonstrates that the impact of land plants on climate and hence on atmospheric CO2 is as important as their geochemical effect through the enhancement of chemical weathering of the continental surface. Our GEOCLIM-LPJ simulations also define a climatic baseline for the Mesozoic, around which exceptionally cool and warm events can be identified.

  6. Impact of cosmic rays and solar energetic particles on the Earth’s ionosphere and atmosphere

    Directory of Open Access Journals (Sweden)

    Mateev Lachezar

    2013-03-01

    Full Text Available A brief review of the study during COST Action ES0803 of effects due to cosmic rays (CR and solar energetic particles (SEP in the ionosphere and atmosphere is presented. Models CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere and application of CORSIKA (COsmic Ray SImulations for KAscade code are considered. They are capable to compute the cosmic ray ionization profiles at a given location, time, solar and geomagnetic activity. Intercomparison of the models, as well as comparison with direct measurements of the atmospheric ionization, validates their applicability for the entire atmosphere and for the different levels of the solar activity. The effects of CR and SEP can be very strong locally in the polar cap regions, affecting the physical-chemical and electrical properties of the ionosphere and atmosphere. Contributions here were also made by the anomalous CR, whose ionization is significant at high geomagnetic latitudes (above 65°–70°. Several recent achievements and application of CR ionization models are briefly presented. This work is the output from the SG 1.1 of the COST ES0803 action (2008–2012 and the emphasis is given on the progress achieved by European scientists involved in this collaboration.

  7. Contribution of the infrasound technology to characterize large scale atmospheric disturbances and impact on infrasound monitoring

    Science.gov (United States)

    Blanc, Elisabeth; Le Pichon, Alexis; Ceranna, Lars; Pilger, Christoph; Charlton Perez, Andrew; Smets, Pieter

    2016-04-01

    The International Monitoring System (IMS) developed for the verification of the Comprehensive nuclear-Test-Ban Treaty (CTBT) provides a unique global description of atmospheric disturbances generating infrasound such as extreme events (e.g. meteors, volcanoes, earthquakes, and severe weather) or human activity (e.g. explosions and supersonic airplanes). The analysis of the detected signals, recorded at global scales and over near 15 years at some stations, demonstrates that large-scale atmospheric disturbances strongly affect infrasound propagation. Their time scales vary from several tens of minutes to hours and days. Their effects are in average well resolved by the current model predictions; however, accurate spatial and temporal description is lacking in both weather and climate models. This study reviews recent results using the infrasound technology to characterize these large scale disturbances, including (i) wind fluctuations induced by gravity waves generating infrasound partial reflections and modifications of the infrasound waveguide, (ii) convection from thunderstorms and mountain waves generating gravity waves, (iii) stratospheric warming events which yield wind inversions in the stratosphere, (iv)planetary waves which control the global atmospheric circulation. Improved knowledge of these disturbances and assimilation in future models is an important objective of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project. This is essential in the context of the future verification of the CTBT as enhanced atmospheric models are necessary to assess the IMS network performance in higher resolution, reduce source location errors, and improve characterization methods.

  8. The space and time impacts on U.S. regional atmospheric CO2 concentrations from a high resolution fossil fuel CO2 emissions inventory

    OpenAIRE

    Katherine D. Corbin; Denning, A Scott; Gurney, Kevin R

    2011-01-01

    To improve fossil fuel CO2 emissions estimates, high spatial and temporal resolution inventories are replacing coarse resolution, annual-mean estimates distributed by population density. Because altering the emissions changes a key boundary condition to inverse-estimated CO2 fluxes, it is essential to analyse the atmospheric impacts of redistributing anthropogenic emissions. Using a coupled ecosystem–atmosphere model, we compare 2004 atmospheric CO2 concentrations resulting from coarse and hi...

  9. Massive impact-induced release of carbon and sulfur gases in the early Earth's atmosphere

    Science.gov (United States)

    Marchi, S.; Black, B. A.; Elkins-Tanton, L. T.; Bottke, W. F.

    2016-09-01

    Recent revisions to our understanding of the collisional history of the Hadean and early-Archean Earth indicate that large collisions may have been an important geophysical process. In this work we show that the early bombardment flux of large impactors (>100 km) facilitated the atmospheric release of greenhouse gases (particularly CO2) from Earth's mantle. Depending on the timescale for the drawdown of atmospheric CO2, the Earth's surface could have been subject to prolonged clement surface conditions or multiple freeze-thaw cycles. The bombardment also delivered and redistributed to the surface large quantities of sulfur, one of the most important elements for life. The stochastic occurrence of large collisions could provide insights on why the Earth and Venus, considered Earth's twin planet, exhibit radically different atmospheres.

  10. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    Directory of Open Access Journals (Sweden)

    Venot Olivia

    2014-02-01

    Full Text Available Ultraviolet (UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm. Within the studied range of temperature, the CO2 cross section can vary by more than two orders of magnitude. This, in particular, makes the absorption of CO2 significant up to wavelengths as high as 230 nm, while it is negligible above 200 nm at 300 K. To investigate the influence of these new data on the photochemistry of exoplanets, we implemented the measured cross section into a 1D photochemical model. The model predicts that accounting for this temperature dependency of CO2 cross section can affect the computed abundances of NH3, CO2, and CO by one order of magnitude in the atmospheres of hot Jupiter and hot Neptune.

  11. Effect of mechanical alloying atmosphere on the microstructure and Charpy impact properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Two types of oxide dispersion strengthened (ODS) ferritic steels, with the composition of Fe-14Cr-2W-0.3Ti-0.3Y2O3 (in weight percent), have been produced by mechanically alloying elemental powders of Fe, Cr, W, and Ti with Y2O3 particles either in argon atmosphere or in hydrogen atmosphere, degassing at various temperatures, and compacting the mechanically alloyed powders by hot isostatic pressing. It was found in particular that mechanical alloying in hydrogen yields a significant reduction in oxygen content in the materials, a lower dislocation density, and a strong improvement in the fast fracture properties of the ODS ferritic steels, as measured by Charpy impact tests.

  12. Impact of agriculture crop residue burning on atmospheric aerosol loading – a study over Punjab State, India

    Directory of Open Access Journals (Sweden)

    Darshan Singh

    2010-02-01

    Full Text Available The present study deals with the impact of agriculture crop residue burning on aerosol properties during October 2006 and 2007 over Punjab State, India using ground based measurements and multi-satellite data. Spectral aerosol optical depth (AOD and Ångström exponent (α values exhibited larger day to day variation during crop residue burning period. The monthly mean Ångström exponent "α" and turbidity parameter "β" values during October 2007 were 1.31±0.31 and 0.36±0.21, respectively. The higher values of "α" and "β" suggest turbid atmospheric conditions with increase in fine mode aerosols over the region during crop residue burning period. AURA-OMI derived Aerosol Index (AI and Nitrogen dioxide (NO2 showed higher values over the study region during October 2007 compared to October 2006 suggesting enhanced atmospheric pollution associated with agriculture crop residue burning.

  13. Impact of polychlorinated biphenyl (Aroclor 1254) and vitamin C on antioxidant system of rat ventral prostate

    Institute of Scientific and Technical Information of China (English)

    M.Sridhar; P.Venkataraman; S.Dhanammal; A.Arunkumar; M.M.Aruldhas; N.Srinivasan; J.Arunakaran

    2004-01-01

    Aim:To evaluate the effect of polychlorinated biphenyls (PCB) and vitamin C on ventral prostatic antioxidant system in adult male rats.Methods:A group of 20 adult male rats were administered ip Aroclor 1254 in corn oil at a dose of 2 mg.kg-1·day-1 for 30 days.Ten control rats were administered only the vehicle.After 30 days the treated rats were divided at random into 2 sub-groups of 10 animals each.One sub-group received vitamin C at a dose of 500 mg.kg-1·day-1 for 10 days.The other group was maintained as Aroclor 1254 control.Twenty-four hours after the last treatment the rats were killed by decapitation.Ventral prostatic homogenate was prepared and used for the estimation of enzymatic antioxidants,including superoxide dismutase (SOD),catalase (CAT) and glutathione-S-transferase (GST) and hydrogen peroxide (H2O2),lipid peroxidation (LPO) and prostatic acid phosphatase.The serum levels of total T3,total T4,TSH,testosterone and estradiol were also assayed.Results:The body weight and ventral prostatic weight were reduced in PCB treated rats.The activities of SOD,CAT,GST and acid phosphatase were decreased while the levels of H2O2 and lipid peroxidation were increased in the ventral prostate of PCB treated rats.Administration of vitamin C restored these parameters.Serum levels of thyroid hormones,estradiol and testosteron ewere decreased in PCB treated animals.Administration of vitamin C restored the thyroid hormone levels.Conclusion:PCB induces oxidative stress and decreases the antioxidant enzymes in the ventral prostate of adult male rats;the effects could be reversed by the administration of vitamin C.(Asian J Androl 2004 Mar;6:19-22)

  14. Impact of Organic and Inorganic Fertilizers Application on the Phytochemical and Antioxidant Activity of Kacip Fatimah (Labisia pumila Benth)

    OpenAIRE

    Ehsan Karimi; Ali Ghasemzadeh; Jaafar, Hawa Z. E.; Mohd Hafiz Ibrahim

    2013-01-01

    A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah) in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P2O5:10% K2O) and inorganic fertilizer (NPK green; 15% N, 15% P2O5, 15% K2O)] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic f...

  15. Impacts of Multi-Scale Solar Activity on Climate.Part Ⅰ:Atmospheric Circulation Patterns and Climate Extremes

    Institute of Scientific and Technical Information of China (English)

    Hengyi WENG

    2012-01-01

    The impacts of solar activity on climate are explored in this two-part study.Based on the principles of atmospheric dynamics,Part Ⅰ propose an amplifying mechanism of solar impacts on winter climate extremes through changing the atmospheric circulation patterns.This mechanism is supported by data analysis of the sunspot number up to the predicted Solar Cycle 24,the historical surface temperature data,and atmospheric variables of NCEP/NCAR Reanalysis up to the February 2011 for the Northern Hemisphere winters.For low solar activity,the thermal contrast between the low- and high-latitudes is enhanced,so as the mid-latitude baroclinic ultra-long wave activity.The land-ocean thermal contrast is also enhanced,which amplifies the topographic waves.The enhanced mid-latitude waves in turn enhance the meridional heat transport from the low to high latitudes,making the atmospheric “heat engine” more efficient than normal. The jets shift southward and the polar vortex is weakened.The Northern Annular Mode (NAM) index tends to be negative.The mid-latitude surface exhibits large-scale convergence and updrafts,which favor extreme weather/climate events to occur.The thermally driven Siberian high is enhanced,which enhances the East Asian winter monsoon (EAWM).For high solar activity,the mid-latitude circulation patterns are less wavy with less meridional transport.The NAM tends to be positive,and the Siberian high and the EAWM tend to be weaker than normal.Thus the extreme weather/climate events for high solar activity occur in different regions with different severity from those for low solar activity.The solar influence on the midto high-latitude surface temperature and circulations can stand out after renoving the influence from the El Ni(n)o-Southern Oscillation.The atmospheric amplifying mechanism indicates that the solar impacts on climate should not be simply estimated by the magnitude of the change in the solar radiation over solar cycles when it is compared with

  16. The impact of atmospheric species on the degradation of CIGS solar cells

    NARCIS (Netherlands)

    Theelen, M.; Foster, C.; Steijvers, H.; Barreau, N.; Vroon, Z.; Zeman, M.

    2015-01-01

    CIGS solar cells were exposed to liquid water purged with the atmospheric gases carbon dioxide (CO2), oxygen (O2), nitrogen (N2) and air in order to investigate their chemical degradation behavior. The samples were analyzed by electrical, compositional and optical me

  17. The impact of increased atmospheric carbon dioxide on microbial community dynamics in the rhizosphere

    NARCIS (Netherlands)

    Drigo, Barbara

    2009-01-01

    Rising atmospheric CO2 levels are predicted to have major consequences upon carbon cycle feedbacks and the overall functioning of terrestrial ecosystems. Photosynthetic activity and the structure of terrestrial macrophytes is expected to change, but it remains uncertain how this will affect soil-bor

  18. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    Science.gov (United States)

    Graven, Heather D

    2015-08-01

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  19. Assessing the impact of non-tidal atmospheric loading on a Kalman filter-based terrestrial reference frame

    Science.gov (United States)

    Abbondanza, Claudio; Altamimi, Zuheir; Chin, Toshio; Collilieux, Xavier; Dach, Rolf; Gross, Richard; Heflin, Michael; König, Rolf; Lemoine, Frank; Macmillan, Dan; Parker, Jay; van Dam, Tonie; Wu, Xiaoping

    2014-05-01

    The International Terrestrial Reference Frame (ITRF) adopts a piece-wise linear model to parameterize regularized station positions and velocities. The space-geodetic (SG) solutions from VLBI, SLR, GPS and DORIS used as input in the ITRF combination process account for tidal loading deformations, but ignore the non-tidal part. As a result, the non-linear signal observed in the time series of SG-derived station positions in part reflects non-tidal loading displacements not introduced in the SG data reduction. In this analysis, we assess the impact of non-tidal atmospheric loading (NTAL) corrections on the TRF computation. Focusing on the a-posteriori approach, (i) the NTAL model derived from the National Centre for Environmental Prediction (NCEP) surface pressure is removed from the SINEX files of the SG solutions used as inputs to the TRF determinations; (ii) adopting a Kalman-filter based approach, two distinct linear TRFs are estimated combining the 4 SG solutions with (corrected TRF solution) and without the NTAL displacements (standard TRF solution). Linear fits (offset and atmospheric velocity) of the NTAL displacements removed during step (i) are estimated accounting for the station position discontinuities introduced in the SG solutions and adopting different weighting strategies. The NTAL-derived (atmospheric) velocity fields are compared to those obtained from the TRF reductions during step (ii). The consistency between the atmospheric and the TRF-derived velocity fields is examined. We show how the presence of station position discontinuities in SG solutions degrades the agreement between the velocity fields and compare the effect of different weighting structure adopted while estimating the linear fits to the NTAL displacements. Finally, we evaluate the effect of restoring the atmospheric velocities determined through the linear fits of the NTAL displacements to the single-technique linear reference frames obtained by stacking the standard SG SINEX files

  20. External costs of atmospheric Pb emissions: valuation of neurotoxic impacts due to inhalation

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Thomsen, Marianne; Frohn, Lise;

    2010-01-01

    The Impact Pathway Approach (IPA) is an innovative methodology to establish links between emissions, related impacts and monetary estimates. Only few attempts have so far been presented regarding emissions of metals; in this study the external costs of airborne lead (Pb) emissions are assessed us...

  1. Evaluation of the use of Syzygium cumini fruit extract as an antioxidant additive in orange juice and its sensorial impact.

    Science.gov (United States)

    Tobal, Thaise Mariá; da Silva, Roberto; Gomes, Eleni; Bolini, Helena Maria André; Boscolo, Mauricio

    2012-05-01

    This work is an exploratory study of the possibility of promoting the consumption of Syzygium cumini fruit by adding its extract to orange juice making good use of its functional (antioxidant) properties. S. cumini fruit extract was characterized in terms of its anthocyanin content (2.11 g/100 g expressed in cyanidine-3-glucoside equivalents), total phenolic compounds (360 mg/100 g expressed in gallic acid equivalents) and antioxidant capacity evaluated by the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging method. The effects of the addition of S. cumini fruit crude extract as well as its chromatographic fractions on the juice were assessed chemically by headspace solid-phase micro-extraction and gas chromatography coupled with a mass spectrometry detector. Only six compounds had their chromatographic peak intensities clearly changed and the results are discussed in terms of the inhibition of the formation of 2-octanone, hexanol, α-copaene, and α-panasinsene and the conservation of octyl acetate and p-menth-1-en-9-ol. Sensory evaluation of orange juice with and without S. cumini crude extract addition did not show any significant differences in the sensorial profile, discriminative and acceptance tests. PMID:21981004

  2. Impact of marine mercury cycling on coastal atmospheric mercury concentrations in the North- and Baltic Sea region

    Directory of Open Access Journals (Sweden)

    Johannes Bieser

    2016-06-01

    Full Text Available Abstract The cycling of mercury between ocean and atmosphere is an important part of the global Hg cycle. Here we study the regional contribution of the air-sea exchange in the North- and Baltic Sea region. We use a newly developed coupled regional chemistry transport modeling (CTM system to determine the flux between atmosphere and ocean based on the meteorological model COSMO-CLM, the ocean-ecosystem model ECOSMO, the atmospheric CTM CMAQ and a newly developed module for mercury partitioning and speciation in the ocean (MECOSMO. The model was evaluated using atmospheric observations of gaseous elemental mercury (GEM, surface concentrations of dissolved gaseous mercury (DGM, and air-sea flux (ASF calculations based on observations made on seven cruises in the western and central Baltic Sea and three cruises in the North Sea performed between 1991 and 2006. It was shown that the model is in good agreement with observations: DGM (Normalized Mean Bias NMB=-0.27 N=413, ASF (NMB=-0.32, N=413, GEM (NMB=0.07, N=2359. Generally, the model was able to reproduce the seasonal DGM cycle with the best agreement during winter and autumn (NMBWinter=-0.26, NMBSpring=-0.41, NMBSummer=-0.29, NMBAutumn=-0.03. The modelled mercury evasion from the Baltic Sea ranged from 3400 to 4000 kg/a for the simulation period 1994–2007 which is on the lower end of previous estimates. Modelled atmospheric deposition, river inflow and air-sea exchange lead to an annual net Hg accumulation in the Baltic Sea of 500 to 1000 kg/a. For the North Sea the model calculates an annual mercury flux into the atmosphere between 5700 and 6000 kg/a. The mercury flux from the ocean influenced coastal atmospheric mercury concentrations. Running CMAQ coupled with the ocean model lead to better agreement with GEM observations. Directly at the coast GEM concentrations could be increased by up to 10% on annual average and observed peaks could be reproduced much better. At stations 100km downwind

  3. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    Science.gov (United States)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  4. The impact of boreal deciduous and evergreen forests on atmospheric CO2 seasonality

    Science.gov (United States)

    Welp, L.; Graven, H. D.; Keeling, R. F.; Bi, J.

    2015-12-01

    The seasonal cycle of atmospheric CO2 is largely controlled by the terrestrial biosphere. It is well known that the seasonal amplitude of net ecosystem productivity (NEP) is the largest in the far north, where forest productivity is compressed into a short growing season. Since 1960, the seasonal amplitude of atmospheric CO2 north of 45N has increased by 35-55%. The increase in the seasonal amplitude is a difficult benchmark for coupled climate-carbon models to replicate. In fact, the models vary widely in their mean seasonal cycle representation. The boreal region has a strong influence on CO2 seasonality at Barrow. Deciduous and evergreen plant functional types (PFTs) have different patterns of NEP. We identified four pairs of nearby deciduous and evergreen forest PFTs with eddy covariance measurements. Evergreen forests show an early peak in NEP in May-June, while deciduous forests have a larger peak in NEP later in June-July. The influence of each PFT on the seasonal cycle at Barrow was computed from atmospheric transport results. We normalized the amplitude influence by the growing season NEP of the tower-based PFT flux and found that deciduous forests have 1.4 to 1.8 times more influence (per unit of growing season NEP) at Barrow than evergreen PFT. This diagnosis depends on the timing of the sharp seasonal draw-down at Barrow, which occurs too late to be explained by evergreen forests. The cycle at Barrow therefore appears to be strongly influenced by deciduous PFT, despite the dominance of evergreen PFTs in boreal forests. This paradoxical conclusion is also reached when examining the seasonality of land surface fluxes calculated using atmospheric inverse methods. We examine how these different PFTs, and possible trends in relative abundance, affect the seasonality of atmosphere CO2 using FluxNet data and atmospheric transport modelling. Our results highlight the importance of parameterizing multiple PFTs or individual species within grid cells in models in

  5. Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, M.; Wagner, M. J.

    2011-08-01

    Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.

  6. Coupled Atmosphere-Fire Simulations of Fireflux: Impacts of Model Resolution on Model Performance

    CERN Document Server

    Kochanski, Adam K; Jenkins, M A; Mandel, J; Beezley, J D

    2011-01-01

    The ability to forecast grass fire spread could be of a great importance for agencies making decisions about prescribed burns. However, the usefulness of the models used for fire-spread predictions is limited by the time required for completing the coupled atmosphere-fire simulations. In this study we analyze the sensitivity of a coupled model with respect to the vertical resolution of the atmospheric grid and the resolution of fire mesh that both affect computational performance of the model. Based on the observations of the plume properties recorded during the FireFlux experiment (Clements et al., 2007), we try to establish the optimal model configuration that provides realistic results for the least computational expense.

  7. The Impact of Oceanic Heat Transport on the Atmospheric Circulation: a Thermodynamic Perspective

    CERN Document Server

    Schröder, Alexander; Lunkeit, Frank

    2014-01-01

    The present study investigates how global thermodynamic properties of the climate system are affected by the changes in the intensity of the imposed oceanic heat transport in an atmospheric general circulation model in aqua-planet configuration. Increasing the poleward oceanic heat transport results in an overall increase in the surface temperature and a decrease in the equator-to-pole surface temperature difference as a result of the ice-albedo feedback. Following the classical ansatz by Stone, the atmospheric heat transport changes in such a way that the total poleward heat transport remains almost unchanged. We also find that the efficiency of the climate machine, the intensity of the Lorenz energy cycle and the material entropy production of the system decline with increased oceanic heat transport which suggests that the climate system becomes less efficient and turns into a state of reduced entropy production, as the enhanced oceanic transport performs a stronger large-scale mixing between geophysical fl...

  8. Impact of atmospheric clutter on Doppler-limited gas sensors in the submillimeter/terahertz.

    Science.gov (United States)

    Medvedev, Ivan R; Neese, Christopher F; Plummer, Grant M; De Lucia, Frank C

    2011-06-20

    It is well known that clutter (spectral interference) from atmospheric constituents can be a severe limit for spectroscopic point sensors, especially where high sensitivity and specificity are required. In this paper, we will show for submillimeter/terahertz (SMM/THz) sensors that use cw electronic techniques the clutter limit for the detection of common target gases with absolute specificity (probability of false alarm ≪ 10⁻¹⁰) is in the ppt (1 part in 10¹²) range or lower. This is because the most abundant atmospheric gases are either transparent to SMM/THz radiation (e.g., CO₂) or have spectra that are very sparse relative to the 10⁵ Doppler-limited resolution elements available (e.g., H₂O). Moreover, the low clutter limit demonstrated for cw electronic systems in the SMM/THz is independent of system size and complexity.

  9. Proceedings of impact of aircraft emissions upon the atmosphere. V. 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The study of the effect of aircraft on atmosphere is a new challenge that the scientific community has to face. This conference`s topics are various aspects of this challenge. The seven sessions of Volume 1 are: Present status and perspectives; Emission and traffic; Physics and chemistry of the aircraft wake; Natural and anthropogenic emissions - specific instrumentation; Global scale - chemistry; Global scale - climate. The 51 papers of Vol. 1. were indexed and abstracted individually for the Energy Database. (R.P.)

  10. Impact of assimilation window length on diurnal features in a Mars atmospheric analysis

    Directory of Open Access Journals (Sweden)

    Yongjing Zhao

    2015-05-01

    Full Text Available Effective simulation of diurnal variability is an important aspect of many geophysical data assimilation systems. For the Martian atmosphere, thermal tides are particularly prominent and contribute much to the Martian atmospheric circulation, dynamics and dust transport. To study the Mars diurnal variability and Mars thermal tides, the Geophysical Fluid Dynamics Laboratory Mars Global Climate Model with the 4D-local ensemble transform Kalman filter (4D-LETKF is used to perform an analysis assimilating spacecraft temperature retrievals. We find that the use of a ‘traditional’ 6-hr assimilation cycle induces spurious forcing of a resonantly enhanced semi-diurnal Kelvin waves represented in both surface pressure and mid-level temperature by forming a wave 4 pattern in the diurnal averaged analysis increment that acts as a ‘topographic’ stationary forcing. Different assimilation window lengths in the 4D-LETKF are introduced to remove the artificially induced resonance. It is found that short assimilation window lengths not only remove the spurious resonance, but also push the migrating semi-diurnal temperature variation at 50 Pa closer to the estimated ‘true’ tides even in the absence of a radiatively active water ice cloud parameterisation. In order to compare the performance of different assimilation window lengths, short-term to mid-range forecasts based on the hour 00 and 12 assimilation are evaluated and compared. Results show that during Northern Hemisphere summer, it is not the assimilation window length, but the radiatively active water ice clouds that influence the model prediction. A ‘diurnal bias correction’ that includes bias correction fields dependent on the local time is shown to effectively reduce the forecast root mean square differences between forecasts and observations, compensate for the absence of water ice cloud parameterisation and enhance Martian atmosphere prediction. The implications of these results for

  11. Soil moisture variability and its possible impact on the atmosphere : A case in Sri Lanka

    OpenAIRE

    Yamanaka, Tsutomu; Kaihotsu, Ichirow; Shimada, Jun; Nandakumar, Vythilingam

    2001-01-01

    Time series analyses of soil moisture, rainfall, air temperature and other hydrometeorological components observed at inland area of Sri Lanka in 1994 were carried out. Auto-correlation analysis gives a time scale from 10 to 30 days as persistency of soil moisture anomaly, which is considerably small relative to that under midlatitude temperate climate and is shorter than that for atmospheric temperature. Two dominant periodicities are detected from spectral analysis : 45-60-day period (espec...

  12. Longwave atmospheric radiation as a possible indicator of the aviation impact

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, N.A. [Central Aerological Observatory of the Russian Federal Service for Hydrometeorology and Environmental Monitoring, Moscow (Russian Federation)

    1997-12-31

    Aircraft emissions changing composition of the atmospheric air should be sensed by radiation parameters, such as downward (in first turn) and upward long-wave fluxes. It might be supposed that the accurate measurements of long-wave (LW) radiation fluxes in regions of crowded aircraft routes time outside these regions, could detect the influence. Main transformation of the long-wave radiation (LWR) proceeds in the troposphere which absorbs and irradiates the LWR. The only mass method of the LWR measurements in the free atmosphere became the radiometer probe. In the former USSR it was successfully developed in 1961, and since 1963 the special radiometer sounding network started to make regular observations over the USSR territory. Rather small spatial variations of the downward LWR flux was observed indicating rather high homogeneity of the atmosphere composition. Analysis of the seasonal variations of the downward LWR has revealed that over some stations it has the opposite course of changes from summer to winter and it is mainly observed at rather high levels. (R.P.) 10 refs.

  13. The Impacts of Atmospheric Stability on the Accuracy of Wind Speed Extrapolation Methods

    Directory of Open Access Journals (Sweden)

    Jennifer F. Newman

    2014-01-01

    Full Text Available The building of utility-scale wind farms requires knowledge of the wind speed climatology at hub height (typically 80–100 m. As most wind speed measurements are taken at 10 m above ground level, efforts are being made to relate 10-m measurements to approximate hub-height wind speeds. One common extrapolation method is the power law, which uses a shear parameter to estimate the wind shear between a reference height and hub height. The shear parameter is dependent on atmospheric stability and should ideally be determined independently for different atmospheric stability regimes. In this paper, data from the Oklahoma Mesonet are used to classify atmospheric stability and to develop stability-dependent power law fits for a nearby tall tower. Shear exponents developed from one month of data are applied to data from different seasons to determine the robustness of the power law method. In addition, similarity theory-based methods are investigated as possible alternatives to the power law. Results indicate that the power law method performs better than similarity theory methods, particularly under stable conditions, and can easily be applied to wind speed data from different seasons. In addition, the importance of using co-located near-surface and hub-height wind speed measurements to develop extrapolation fits is highlighted.

  14. Atmospheric 3H impact assessment (2004-2008) around Narora Atomic Power Station

    International Nuclear Information System (INIS)

    Atmospheric tritium activity is measured regularly around Narora Atomic Power Station (NAPS) since gaseous waste, which contains tritium, is being released through a 145 m high stack at NAPS site. Atmospheric data collected during 2004-2008 shows a large variation of 3H concentration in air, fluctuating in the range of ≤0.2-91.6 Bq.m-3. Significantly, higher tritium levels were measured in samples near the site boundary (1.6 km) of NAPS compared to off-site locations. The atmospheric dilution factor was found to be in the range of 1.1x10-7-7.3x10-7 s.m-3. The scavenging of NAPS site was found to be varying from 0.2x104 to 14.1x104 (Bq.m-3 rain water per Bqm-3 air). The inhalation dose to a member of general public at different distances (1.6-30 km) from NAPS site was found to be in the range of 0.21 μSv.y-1. (author)

  15. Lithium spectral line formation in stellar atmospheres. The impact of convection and NLTE effects

    CERN Document Server

    Klevas, J; Steffen, M; Caffau, E; Ludwig, H -G

    2015-01-01

    Different simplified approaches are used to account for the non-local thermodynamic equilibrium (NLTE) effects with 3D hydrodynamical model atmospheres. In certain cases, chemical abundances are derived in 1D NLTE and corrected for the 3D effects by adding 3D-1D LTE abundance corrections (3D+NLTE approach). Alternatively, average model atmospheres are sometimes used to substitute for the full 3D hydrodynamical models. We tested whether the results obtained using these simplified schemes (i.e., 3D+NLTE, NLTE) may reproduce those derived using the full 3D NLTE computations. The tests were made using 3D hydrodynamical CO5BOLD model atmospheres of the main sequence (MS), main sequence turn-off (TO), subgiant (SGB), and red giant branch (RGB) stars, all at [M/H]=0.0 and -2.0. Our goal was to investigate the role of 3D and NLTE effects on the formation of the 670.8 nm lithium line by assessing strengths of synthetic 670.8 nm line profiles, computed using 3D/1D NLTE/LTE approaches. Our results show that Li 670.8 n...

  16. Impact of acute exercise on antioxidant enzymes activity and lipid status in blood of patients with hypertension

    Directory of Open Access Journals (Sweden)

    Kostić Nada

    2009-01-01

    Full Text Available Background/Aim. Many studies support the hypothesis that oxidative stress is involved in the pathogenic process of a variety of diseases including hypertension. In humans, hypertension is also considered a state of oxidative stress that can contribute to the development of arteriosclerosis and other hypertension- induced organ damage. The aim of this study was to evaluate an influence of acute physical exercise on antioxidative enzymes activity and lipid status in patients with hypertension. Methods. Forty patients with hypertension and 20 age-matched controls were included in the study. To assess an influence of acute exercise on lipids and antioxidative enzymes activity the following parameters were determined at rest and immediately after the acute cardiopulmonary exercise cycloergometer test: triglycerides (TG, total cholesterol, low density cholesterol (LDL, oxidised LDL cholesterol (OxLDL, superoxide dismutase (SOD, glutathione peroxidase (GSH-Px and plasminogen activator inhibitor (PAI. Results. In basal condition, hypertensive patients compared to the control group had increased, but not significantly, level of Ox LDL (88.61±14.06 vs 79.00±29.26 mmol/L, PAI (3.06±0.56 vs 2.6±0.35 U/mL and activity of GSH-Px (50.22±15.20 vs 44.63±13.73 U/g Hb. After acute exercise test, there was significantly greater level of Ox LDL (79.0±29.26 vs 89.3±29.07 mmol/L; p < 0.05 only in the control group. GSH-Px activity was significantly decreased only in hypertensive patients after acute exercise (50.22±15.2 vs 42.82±13.42 U/g Hb; p < 0.05, but not in the controls. Conclusion. No significantly elevated Ox LDL, GSH-Px and PAI-1 levels were found in hypertensive patients during basal condition in comparison with healthy subjects. Decreased GSH-Px activity was associated with those in acute exercise only in hypertensive patients. It could be an important indicator of deficiency of physiological antioxidative defense mechanism in hypertensive

  17. Impact of atmospheric molecular absorption on the temporal and spatial evolution of ultra-short optical pulses.

    Science.gov (United States)

    Gebhardt, Martin; Gaida, Christian; Stutzki, Fabian; Hädrich, Steffen; Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas

    2015-06-01

    We present a rigorous study on the impact of atmospheric molecular absorption on the linear propagation of ultrashort pulses in the mid-infrared wavelength region. An ultrafast thulium-based fiber laser was employed to experimentally investigate ultrashort-pulse propagation through the atmosphere in a spectral region containing several strong molecular absorption lines. The atmospheric absorption profile causes a significant degradation of the pulse quality in the time domain as well as a distortion of the transverse beam profile in the spatial domain. Numerical simulations carried out in the small signal limit accurately reproduce the experimental observations in the time domain and reveal that the relative loss in peak power after propagation can be more than twice as high as the relative amount of absorbed average power. Although their nature is purely linear (i.e. the intensities considered are sufficiently low) the discussed effects represent significant challenges to performance-scaling of mid-infrared ultrafast lasers operating in spectral regions with molecular absorption bands. Guidelines for an efficient mitigation of the pulse quality degradation and the beam profile distortion are discussed. PMID:26072749

  18. Aerosol hygroscopicity and its impact on atmospheric visibility and radiative forcing in Guangzhou during the 2006 PRIDE-PRD campaign

    Science.gov (United States)

    Liu, Xingang; Zhang, Yuanhang; Cheng, Yafang; Hu, Min; Han, Tingting

    2012-12-01

    The objective of this study is to quantify the relation of aerosol chemical compositions and optical properties, and to assess the impact of relative humidity (RH) on atmospheric visibility and aerosol direct radiative forcing (ADRF). Mass concentration and size distribution of aerosol chemical compositions as well as aerosol optical properties were concurrently measured at Guangzhou urban site during the PRD (Pearl River Delta) campaign from 1 to 31 July, 2006. Gaseous pollutant NO2 and meteorological parameter were simultaneously monitored. Compared with its dry condition, atmospheric ambient extinction coefficient σext(RH) averagely increased about 51% and atmospheric visibility deceased about 35%, among which RH played an important role on the optical properties of water soluble inorganic salts. (NH4)2SO4 is the most important component responsible for visibility degradation at Guangzhou. In addition, the asymmetry factor g increased from 0.64 to 0.74 with the up-scatter fraction β decreasing from 0.24 to 0.19 when RH increasing from 40% to 90%. At 80% RH, the ADRF increased about 280% compared to that at dry condition and it averagely increased about 100% during the campaign under ambient conditions. It can be inferred that aerosol water content is a key factor and could not be ignored in assessing the role of aerosols in visibility impairment and radiative forcing, especially in the regions with high RH.

  19. Exploring the impacts of land-use change on tropical rainfall using satellite remote sensing and atmospheric back trajectories

    Science.gov (United States)

    Spracklen, Dominick; Arnold, Stephen; Taylor, Christopher

    2013-04-01

    Vegetation affects precipitation patterns through altering moisture, energy and trace-gas fluxes between the surface and atmosphere. Here we explore the effect of tropical vegetation and land-use change on precipitation using satellite remote sensed observations of precipitation from the tropical Rainfall Measuring Mission and other satellites combined (TRMM3B42) and leaf area index (LAI) from the Moderate Resolution Imaging Spectroradiometer (MODIS). We combine these observations with a Lagrangian atmospheric transport model which we use to describe daily variability in atmospheric transport patterns. We calculate cumulative exposure of air masses to tropical vegetation and explore relationships between this exposure and observed precipitation. We use remote sensed observations of land-use change that has occurred over recent decades to explore how exposure of air masses to vegetation has changed. We find that for more than 60% of the tropical land surface, air that has experienced a large cumulative exposure to vegetation in the preceding few days produces at least twice as much rain as air that has little exposure to vegetation. To understand potential mechanisms behind this relationship we explore the atmospheric water budget along analysed back trajectories using specific humidity from analysed meteorological fields combined with global land-surface model output of evapotranspiration (ET). We find that ET in air masses with large exposure to vegetation maintains atmospheric moisture sufficiently to explain observed relationships with precipitation. We estimate the impact of 2000-2010 land-use change on the exposure of air masses to vegetation. We focus on regions of rapid-land use change and explore how these changes have altered air mass exposure to vegetation. We attempt to identify locations where large enough changes may have already occurred to allow an observable impact on precipitation. Finally we use a business-as-usual scenario of Amazonian

  20. The Impact of Clouds on Ecosystem-Atmosphere CO18O Exchanges in the U.S. Great Plains

    Science.gov (United States)

    Still, C. J.; Riley, W. J.; Biraud, S. C.; Noone, D. C.; Berry, J. A.

    2005-12-01

    The downward excursion in δ18O of atmospheric CO2 observed during the 1990s and the large interannnual variability characteristic of this isotopologue are not understood. We hypothesize that these variations in δ18O of atmospheric CO2 may be linked to global-scale variations in cloud cover and its influence on biosphere-atmosphere CO18O exchanges. Recent work has demonstrated the influence of clouds on canopy photosynthesis through increases in the diffuse radiation fraction and relative humidity, combined with decreases in leaf temperature. In concert, these alterations tend to increase canopy photosynthesis, which should also increase CO18O fluxes. However, photosynthetic CO18O fluxes also depend on the δ18O of leafwater, and enhanced cloudiness should decrease the δ18O of leafwater by enhancing relative humidity. Thus, the net impact of differing cloud cover on biosphere-atmosphere CO18O exchanges is difficult to predict. To capture these contrasting effects, we employed a comprehensive ecosystem isotope model (ISOLSM) in the southern great plains region of Oklahoma and Kansas. This region is particularly amenable for such a study because of the density of cloud property and radiation measurements. The region contains natural and agricultural ecosystems representing a variety of photosynthetic pathways and growth forms, including tallgrass prairie pastures, broadleaf forests, and crops. To drive the model across the entire region, we used Mesonet meteorological data collected at 120 stations in 2004, as well as precipitation δ18O values from the National Atmospheric Deposition Program network. LAI profiles from 2004 were derived from MODIS data. Our results suggest a large impact of clouds on photosynthetic CO2 and CO18O fluxes across this region. In an unstressed broadleaf deciduous forest (LAI=6.3), three sequential midsummer days with contrasting cloud cover illustrate this impact. Julian Day 222 is sunny, JD 223 is partly cloudy, and JD 224 is very

  1. The impact of facility relocation on patients' perceptions of ward atmosphere and quality of received forensic psychiatric care.

    Science.gov (United States)

    Alexiou, Eirini; Degl' Innocenti, Alessio; Kullgren, Anette; Wijk, Helle

    2016-08-01

    In recent years, large groups of forensic psychiatric patients have been relocated into new medium- and maximum-security forensic psychiatric facilities in Sweden, where a psychosocial care approach is embedded. From this perspective and on the assumption that physical structures affect the therapeutic environment, a prospective longitudinal study was designed to investigate the impact of the facility relocation of three forensic psychiatric hospitals on patients' perceptions of ward atmosphere and quality of received forensic psychiatric care. Participants were patients over 18 years of age sentenced to compulsory forensic psychiatric treatment. Data were obtained by validated questionnaires. Overall, 58 patients (78%) answered the questionnaires at baseline with a total of 25 patients (34%) completing follow-up 1 at six months and 11 patients (15%) completing follow-up 2, one year after relocation. Approximately two-thirds of the participants at all time-points were men and their age range varied from 18 to 69. The results of this study showed that poor physical environment features can have a severe impact on care quality and can reduce the possibilities for person-centered care. Furthermore, the study provides evidence that the patients' perceptions of person-centered care in forensic psychiatric clinics are highly susceptible to factors in the physical and psychosocial environment. Future work will explore the staff's perception of ward atmosphere and the possibilities to adapt a person-centered approach in forensic psychiatric care after facility relocation. PMID:27213839

  2. The impact of facility relocation on patients' perceptions of ward atmosphere and quality of received forensic psychiatric care.

    Science.gov (United States)

    Alexiou, Eirini; Degl' Innocenti, Alessio; Kullgren, Anette; Wijk, Helle

    2016-08-01

    In recent years, large groups of forensic psychiatric patients have been relocated into new medium- and maximum-security forensic psychiatric facilities in Sweden, where a psychosocial care approach is embedded. From this perspective and on the assumption that physical structures affect the therapeutic environment, a prospective longitudinal study was designed to investigate the impact of the facility relocation of three forensic psychiatric hospitals on patients' perceptions of ward atmosphere and quality of received forensic psychiatric care. Participants were patients over 18 years of age sentenced to compulsory forensic psychiatric treatment. Data were obtained by validated questionnaires. Overall, 58 patients (78%) answered the questionnaires at baseline with a total of 25 patients (34%) completing follow-up 1 at six months and 11 patients (15%) completing follow-up 2, one year after relocation. Approximately two-thirds of the participants at all time-points were men and their age range varied from 18 to 69. The results of this study showed that poor physical environment features can have a severe impact on care quality and can reduce the possibilities for person-centered care. Furthermore, the study provides evidence that the patients' perceptions of person-centered care in forensic psychiatric clinics are highly susceptible to factors in the physical and psychosocial environment. Future work will explore the staff's perception of ward atmosphere and the possibilities to adapt a person-centered approach in forensic psychiatric care after facility relocation.

  3. Three-dimensional modeling of HCFC-123 in the atmosphere: assessing its potential environmental impacts and rationale for continued use.

    Science.gov (United States)

    Wuebbles, Donald J; Patten, Kenneth O

    2009-05-01

    HCFC-123 (C2HCl2F3) is used in large refrigeration systems and as a fire suppression agent blend. Like other hydrochlorofluorocarbons, production and consumption of HCFC-123 is limited under the Montreal Protocol on Substances that Deplete the Ozone Layer. The purpose of this study is to update the understanding of the current and projected impacts of HCFC-123 on stratospheric ozone and on climate and to discuss the potential environmental effects from continued use of this chemical for specific applications. For the first time, the Ozone Depletion Potential (ODP) of a HCFC is determined using a three-dimensional model (MOZART-3) of atmospheric physics and chemistry. All previous studies have relied on results from two-dimensional models. The derived HCFC-123 ODP of 0.0098 is smaller than previous values. Analysis of the projected uses and emissions of HCFC-123, assuming reasonable levels of projected growth and use in centrifugal chiller and fire suppressant applications, suggests an extremely small impact on the environment due to its short atmospheric lifetime, low ODP, low Global Warming Potential (GWP), and the small production and emission of its limited applications. The current contribution of HCFC-123 to stratospheric reactive chlorine is too small to be measurable.

  4. Three-dimensional modeling of HCFC-123 in the atmosphere: assessing its potential environmental impacts and rationale for continued use.

    Science.gov (United States)

    Wuebbles, Donald J; Patten, Kenneth O

    2009-05-01

    HCFC-123 (C2HCl2F3) is used in large refrigeration systems and as a fire suppression agent blend. Like other hydrochlorofluorocarbons, production and consumption of HCFC-123 is limited under the Montreal Protocol on Substances that Deplete the Ozone Layer. The purpose of this study is to update the understanding of the current and projected impacts of HCFC-123 on stratospheric ozone and on climate and to discuss the potential environmental effects from continued use of this chemical for specific applications. For the first time, the Ozone Depletion Potential (ODP) of a HCFC is determined using a three-dimensional model (MOZART-3) of atmospheric physics and chemistry. All previous studies have relied on results from two-dimensional models. The derived HCFC-123 ODP of 0.0098 is smaller than previous values. Analysis of the projected uses and emissions of HCFC-123, assuming reasonable levels of projected growth and use in centrifugal chiller and fire suppressant applications, suggests an extremely small impact on the environment due to its short atmospheric lifetime, low ODP, low Global Warming Potential (GWP), and the small production and emission of its limited applications. The current contribution of HCFC-123 to stratospheric reactive chlorine is too small to be measurable. PMID:19534136

  5. Modeling impacts of NH3 on uptake of H2SO4 by charged nucleating nanoparticles in the Earth's atmosphere

    Science.gov (United States)

    Nadykto, A. B.; Nazarenko, K. M.; Markov, P. N.; Yu, F.

    2016-06-01

    The understanding of the role of ammonia, a well-known stabilizer of binary sulfuric acid-water clusters, in the gas-to-nanoparticle conversion in the Earth atmosphere is critically important for the assessment of aerosol radiative forcing associated with the climate changes. The sulfuric acid H2SO4 is present in the atmosphere in the form of the gas-phase hydrates (H2SO4)(H2O)n, whose interaction with NH3 leads to the formation of more stable bisulfate clusters (NH3)(H2SO4)(H2O)n. Although the impact of NH3 on the thermochemical stability of binary clusters nucleating homogeneously has been studied in some detail in the past, the effect of ammonia on other microphysical properties relevant to nucleation remains insufficiently well understood. In the present study, the effect of ammonia on the electrical dipole moment controlling the nucleation of airborne ions via the dipole-charge interaction has been investigated using the Density Functional Theory (DFT), ab initio MP2 and model chemistry G3 methods. The presence of ammonia in (H2SO4)(H2O)n is found to lead to very large enhancement in the dipole moment, which exceeds 2.0-2.5 Debyes (˜60-80%), 3.7-5.0 Debyes (˜90-180%), 1.4-4.5 Debyes (˜50-150%) and 2.1-5.5 Debyes (˜60-700%) for n = 0, n = 1, n = 2 and n = 3, respectively. The implications of this include the significantly increased uptake of the sulfuric acid, the key atmospheric nucleation precursor, by airborne ions and neutrals (due to dipole-dipole interaction), enhanced nucleation rates and the elevated production of ultrafine particles, which cause adverse health impacts.

  6. Impacts of greenhouse gases and aerosol direct and indirect effects on clouds and radiation in atmospheric GCM simulations of the 1930-1989 period

    OpenAIRE

    Quaas, Johannes; Dufresne, Jean-Louis; Boucher, Olivier; Le Treut, Hervé

    2015-01-01

    Among anthropogenic perturbations of the Earth\\'s atmosphere, greenhouse gases and aerosols are considered to have a major impact on the energy budget through their impact on radiative fluxes. We use three ensembles of simulations with the LMDZ general circulation model to investigate the radiative impacts of five species of greenhouse gases (CO2, CH4, N2O, CFC-11 and CFC-12) and sulfate aerosols for the period 1930-1989. Since our focus is on the atmospheric changes in clouds and radiation f...

  7. Observing the Impact of the Anthropocene from Space: the Evolution of Atmospheric Observation

    Science.gov (United States)

    Burrows, John P.

    2016-04-01

    From the Neolithic revolution to the industrial revolution over ~ 10 000 years, the earth's population rose from several millions to 1 Billion powered by energy from a mixture of biofuels, water and solar power and a limited amount of the combustion of coal. The industrial revolution began in the UK in the late 18th century, and has been fuelled by the combustion of fossil fuels, initially coal but then oil and gas. This has led to a dramatic rise in both the human population, now comprising over 7 Billion with more than 50% living in urban areas, and its standard of living. The expectation is that by 2050 population will be of the order of 10 Billion with 75% dwelling in urban areas. Anthropogenic activity has resulted in pollution from the local to the global scale, changes in land use, the destruction of stratospheric ozone, the modification of biogeochemical cycling, the destruction of species, ecosystems and ecosystem services and climate change. The earth has entered a new geological epoch the anthropocene. The observation of atmospheric composition provides a unique early warning of the natural and anthropogenic origins of change. Consistent and consolidated measurements from the local to the global scale are required to test our knowledge of the biogeochemical cycles, which determine atmospheric composition, and to assess and attribute accurately their modification by anthropogenic activity. To achieve global measurements of atmospheric constituents (trace gases, aerosol and cloud parameters) the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY), Project was initiated in the early 1980s. This was the first passive remote sensing space based instrumentation, designed to make simultaneous contiguous measurements of the solar upwelling radiation at the top of the atmosphere from the ultraviolet to the shortwave infrared. The SCIAMACHY project resulted in measurements of the instruments GOME, originally called SCIA-mini, on ESA

  8. Land cover change impacts on atmospheric chemistry: simulating projected large-scale tree mortality in the United States

    Science.gov (United States)

    Geddes, Jeffrey A.; Heald, Colette L.; Silva, Sam J.; Martin, Randall V.

    2016-02-01

    Land use and land cover changes impact climate and air quality by altering the exchange of trace gases between the Earth's surface and atmosphere. Large-scale tree mortality that is projected to occur across the United States as a result of insect and disease may therefore have unexplored consequences for tropospheric chemistry. We develop a land use module for the GEOS-Chem global chemical transport model to facilitate simulations involving changes to the land surface, and to improve consistency across land-atmosphere exchange processes. The model is used to test the impact of projected national-scale tree mortality risk through 2027 estimated by the 2012 USDA Forest Service National Insect and Disease Risk Assessment. Changes in biogenic emissions alone decrease monthly mean O3 by up to 0.4 ppb, but reductions in deposition velocity compensate or exceed the effects of emissions yielding a net increase in O3 of more than 1 ppb in some areas. The O3 response to the projected change in emissions is affected by the ratio of baseline NOx : VOC concentrations, suggesting that in addition to the degree of land cover change, tree mortality impacts depend on whether a region is NOx-limited or NOx-saturated. Consequently, air quality (as diagnosed by the number of days that 8 h average O3 exceeds 70 ppb) improves in polluted environments where changes in emissions are more important than changes to dry deposition, but worsens in clean environments where changes to dry deposition are the more important term. The influence of changes in dry deposition demonstrated here underscores the need to evaluate treatments of this physical process in models. Biogenic secondary organic aerosol loadings are significantly affected across the US, decreasing by 5-10 % across many regions, and by more than 25 % locally. Tree mortality could therefore impact background aerosol loadings by between 0.5 and 2 µg m-3. Changes to reactive nitrogen oxide abundance and partitioning are also locally

  9. Governing processes for reactive nitrogen compounds in the atmosphere in relation to ecosystem, climatic and human health impacts

    Directory of Open Access Journals (Sweden)

    O. Hertel

    2012-07-01

    Full Text Available Reactive nitrogen (Nr compounds have different fates in the atmosphere due to differences in governing processes of physical transport, deposition and chemical transformation. Nr compounds addressed here include reduced nitrogen (NHx: ammonia (NH3 and its reaction product ammonium (NH4+, oxidized nitrogen (NOy: nitrogen monoxide (NO + nitrogen dioxide (NO2 and their reaction products as well as organic nitrogen compounds (organic N. Pollution abatement strategies need to take into account these differences in the governing processes of these compounds when assessing their impact on ecosystem services, biodiversity, human health and climate. NOx (NO + NO2 emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions have little impact on nearby ecosystems because of the small dry deposition rates of NOx. These compounds need to be converted into nitric acid (HNO3 before removal through deposition is efficient. HNO3 sticks quickly to any surface and is thereby either dry deposited or incorporated into aerosols as nitrate (NO3. In contrast to NOx compounds, NH3 has potentially high impacts on ecosystems near the main agricultural sources of NH3 because of its large ground-level concentrations along with large dry deposition rates. Aerosol phase NH4+ and NO3 contribute significantly to background PM2.5 and PM10 (mass of aerosols with a diameter of less than 2.5 and 10 μm, respectively with an impact on radiation balance as well as potentially on human health. Little is known quantitatively and

  10. Role of Atmospheric Chemistry in the Climate Impacts of Stratospheric Volcanic Injections

    Science.gov (United States)

    Legrande, Allegra N.; Tsigaridis, Kostas; Bauer, Susanne E.

    2016-01-01

    The climate impact of a volcanic eruption is known to be dependent on the size, location and timing of the eruption. However, the chemistry and composition of the volcanic plume also control its impact on climate. It is not just sulfur dioxide gas, but also the coincident emissions of water, halogens and ash that influence the radiative and climate forcing of an eruption. Improvements in the capability of models to capture aerosol microphysics, and the inclusion of chemistry and aerosol microphysics modules in Earth system models, allow us to evaluate the interaction of composition and chemistry within volcanic plumes in a new way. These modeling efforts also illustrate the role of water vapor in controlling the chemical evolution, and hence climate impacts, of the plume. A growing realization of the importance of the chemical composition of volcanic plumes is leading to a more sophisticated and realistic representation of volcanic forcing in climate simulations, which in turn aids in reconciling simulations and proxy reconstructions of the climate impacts of past volcanic eruptions. More sophisticated simulations are expected to help, eventually, with predictions of the impact on the Earth system of any future large volcanic eruptions.

  11. The impacts of recent permafrost thaw on land–atmosphere greenhouse gas exchange

    International Nuclear Information System (INIS)

    Permafrost thaw and the subsequent mobilization of carbon (C) stored in previously frozen soil organic matter (SOM) have the potential to be a strong positive feedback to climate. As the northern permafrost region experiences as much as a doubling of the rate of warming as the rest of the Earth, the vast amount of C in permafrost soils is vulnerable to thaw, decomposition and release as atmospheric greenhouse gases. Diagnostic and predictive estimates of high-latitude terrestrial C fluxes vary widely among different models depending on how dynamics in permafrost, and the seasonally thawed ‘active layer’ above it, are represented. Here, we employ a process-based model simulation experiment to assess the net effect of active layer dynamics on this ‘permafrost carbon feedback’ in recent decades, from 1970 to 2006, over the circumpolar domain of continuous and discontinuous permafrost. Over this time period, the model estimates a mean increase of 6.8 cm in active layer thickness across the domain, which exposes a total of 11.6 Pg C of thawed SOM to decomposition. According to our simulation experiment, mobilization of this previously frozen C results in an estimated cumulative net source of 3.7 Pg C to the atmosphere since 1970 directly tied to active layer dynamics. Enhanced decomposition from the newly exposed SOM accounts for the release of both CO2 (4.0 Pg C) and CH4 (0.03 Pg C), but is partially compensated by CO2 uptake (0.3 Pg C) associated with enhanced net primary production of vegetation. This estimated net C transfer to the atmosphere from permafrost thaw represents a significant factor in the overall ecosystem carbon budget of the Pan-Arctic, and a non-trivial additional contribution on top of the combined fossil fuel emissions from the eight Arctic nations over this time period. (paper)

  12. Land use changes and its impacts on air quality and atmospheric patterns

    Science.gov (United States)

    Freitas, E. D.; Mazzoli, C. R.; Martins, L. D.; Martins, J. A.; Carvalho, V.; Andrade, M.

    2013-05-01

    Possible modifications on atmospheric patterns and air quality caused by land use changes are discussed in this work. With the increasing interest in alternative energy sources, mainly due to the replacement of fossil fuels, large part of the Brazilian territory is being used for sugar cane cultivation. The resultant modifications in land use and some activities associated to this crop are studied with some detail through numerical modeling of the atmosphere. The same tool was applied to study the effect of surface type and emission sources over urban areas in the neighborhoods of the cultivated areas, in particular those located in the Metropolitan Area of Campinas, inside the state of São Paulo, Brazil. The main focus of this work was to identify some relationship between these two types of land use modification and its influence on the regional atmospheric circulation patterns and air quality over agricultural and urban areas affected by biomass burning and the traditional sources of pollutants, such as industries and vehicles. First, the effect of urban areas was analyzed and it was possible to identify typical patterns associated with urban heat islands, especially over the city of Campinas. In this region, air temperature differences up to 3 K were detected during night time. During the day, due to the atmospheric conditions of the studied period, this effect was not significant. Afterwards, the effect of sugar cane cultivated regions was discussed. The results show that the regions of sugar cane grow can significantly modify the surface energy fluxes, with direct consequences to the standards of local temperature and humidity and over nearby regions. Sensitivity tests were carried out during part of September, 2007, through the substitution of the sugar cane by a generic crop in the model, and show that during the day the cultivated areas can present temperatures up to 0,65 k higher than those in the case of the generic one. Throughout the dispersion module

  13. Environmental atmospheric impact assessment by the emission of particles in an industrial area

    International Nuclear Information System (INIS)

    The content of metals present in suspended particulate matter was evaluated using analytical related nuclear techniques, in order to discriminate the contribution of different emission sources to the atmospheric concentration in the area of Campana, located in the Province of Buenos Aires. The levels of Ti, V, Cr, Mn, Ni, Cu, Zn, Sr, Ag, Cd y Pb were quantified by Wave Dispersion X-Ray Florescence spectrometry (WDXRF), Total Reflection X-Ray Fluorescence spectrometry (TRXRF) and Inducted Coupled Plasma Absorption Emission spectroscopy (ICP-AES). (author)

  14. Modelling the impact of Baltic Sea upwelling on the atmospheric boundary layer

    OpenAIRE

    Sproson, David; Sahlée, Erik

    2014-01-01

    Coastal upwelling, with a strong sea-surface temperature (SST) signal, is extremely common in the Baltic Sea during the summer months. Although the spatial scale of upwelling is small, its high frequency of occurrence in the semi-enclosed basin may allow the SST signature to have significant feedback onto the lower atmosphere. In this paper, we develop a method to remove the signature of upwelling from SST fields, and use these modified SST fields as the lower boundary condition of an atmosph...

  15. Impact of a Reduced Arctic Sea Ice Cover on Ocean and Atmospheric Properties

    OpenAIRE

    Sedláček, Jan; Knutti, Reto; Martius, Olivia; Beyerle, Urs

    2012-01-01

    The Arctic sea ice cover declined over the last few decades and reached a record minimum in 2007, with a slight recovery thereafter. Inspired by this the authors investigate the response of atmospheric and oceanic properties to a 1-yr period of reduced sea ice cover. Two ensembles of equilibrium and transient simulations are produced with the Community Climate System Model. A sea ice change is induced through an albedo change of 1 yr. The sea ice area and thickness recover in both ensembles a...

  16. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 1: Land transport and shipping

    Directory of Open Access Journals (Sweden)

    M. Righi

    2015-01-01

    Full Text Available Using the EMAC (ECHAM/MESSy Atmospheric Chemistry global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications, we simulate the impact of land transport and shipping emissions on global atmospheric aerosol and climate in 2030. Future emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare the resulting 2030 land-transport- and shipping-induced aerosol concentrations to the ones obtained for the year 2000 in a previous study with the same model configuration. The simulations suggest that black carbon and aerosol nitrate are the most relevant pollutants from land transport in 2000 and 2030 and their impacts are characterized by very strong regional variations during this time period. Europe and North America experience a decrease in the land-transport-induced particle pollution, although in these regions this sector remains a major source of surface-level pollution in 2030 under all RCPs. In Southeast Asia, however, a significant increase is simulated, but in this region the surface-level pollution is still controlled by other sources than land transport. Shipping-induced air pollution is mostly due to aerosol sulfate and nitrate, which show opposite trends towards 2030. Sulfate is strongly reduced as a consequence of sulfur reduction policies in ship fuels in force since 2010, while nitrate tends to increase due to the excess of ammonia following the reduction in ammonium sulfate. The aerosol-induced climate impact of both sectors is dominated by aerosol-cloud effects and is projected to decrease between 2000 and 2030, nevertheless still contributing a significant radiative forcing to Earth's radiation budget.

  17. Impact of uncertainties in atmospheric boundary conditions on ocean model solutions

    Science.gov (United States)

    Chaudhuri, Ayan H.; Ponte, Rui M.; Forget, Gael

    2016-04-01

    We quantify differences in ocean model simulations derived solely from atmospheric uncertainties and investigate how they relate to overall model errors as inferred from comparisons with data. For this purpose, we use a global configuration of the MITgcm to simulate 4 ocean solutions for 2000-2009 using 4 reanalysis products (JRA-25, MERRA, CFSR and ERA-Interim) as atmospheric forcing. The simulations are compared against observations and against each other for selected variables (temperature, sea-level, sea-ice, streamfunctions, meridional heat and freshwater transports). Forcing-induced differences are comparable in magnitude to model-observation misfits for most near-surface variables in the tropics and sub-tropics, but typically smaller at higher latitudes and polar regions. Forcing-derived differences are expectedly largest near the surface and mostly limited to the upper 1000 m but can also be seen as deep as 4000 m, especially in regions of deep water formation. Errors are not necessarily local in nature and can be advected to different basins. Results indicate that while forcing adjustments might suffice in optimization procedures of near-surface fields and at low-to-mid latitudes, other control parameters are likely needed elsewhere. Forcing-induced differences can be dominated by large spatial scales and specific time scales (e.g. annual), and thus appropriate error covariances in space and time need to be considered in optimization methodologies.

  18. Airborne load of Cassia pollen in West Bengal, eastern India: its atmospheric variation and health impact.

    Science.gov (United States)

    Hussain, Mir Musaraf; Mandal, Jyotshna; Bhattacharya, Kashinath

    2013-03-01

    A Burkard personal volumetric sampler was used at Sriniketan, a town about 150 km northwest of Calcutta, in the state of West Bengal, in eastern India to record the frequency of three common airborne Cassia pollen types, Cassia tora, Cassia occidentalis, and Cassia fistula for two consecutive years (2004-2006). Correlation was made between the meteorological factors and the pollen concentration in the atmosphere. The study reports Cassia pollinosis by in vivo skin prick test in respiratory allergic patients. The highest positive reactions were exhibited by C. tora (34.7 %), C. fistula (33.3 %), and C. occidentalis (28.5 %). The allergic potential of these was investigated by in vitro enzyme linked immunosorbent assay test. Their protein components were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in the range of 15.8-81.5 kDa. In C. occidentalis and C. fistula, 11 bands were found, while it was 10 in C. tora. The results show that the Cassia pollen occur significantly in the atmosphere with the potential to elicit an allergic response in susceptible patients.

  19. Atmospheric carbonaceous aerosols from Indo-Gangetic Plain and Central Himalaya: impact of anthropogenic sources.

    Science.gov (United States)

    Ram, Kirpa; Sarin, M M

    2015-01-15

    In the present-day scenario of growing anthropogenic activities, carbonaceous aerosols contribute significantly (∼20-70%) to the total atmospheric particulate matter mass and, thus, have immense potential to influence the Earth's radiation budget and climate on a regional to global scale. In addition, formation of secondary organic aerosols is being increasingly recognized as an important process in contributing to the air-pollution and poor visibility over urban regions. It is, thus, essential to study atmospheric concentrations of carbonaceous species (EC, OC and WSOC), their mixing state and absorption properties on a regional scale. This paper presents the comprehensive data on emission sources, chemical characteristics and optical properties of carbonaceous aerosols from selected urban sites in the Indo-Gangetic Plain (IGP) and from a high-altitude location in the central Himalaya. The mass concentrations of OC, EC and WSOC exhibit large spatio-temporal variability in the IGP. This is attributed to seasonally varying emissions from post-harvest agricultural-waste burning, their source strength, boundary layer dynamics and secondary aerosol formation. The high concentrations of OC and SO4(2-), and their characteristic high mass scattering efficiency, contribute significantly to the aerosol optical depth and scattering coefficient. This has implications to the assessment of single scattering albedo and aerosol radiative forcing on a regional scale. PMID:25199599

  20. Integrating atmospheric and volcanic gas data in support of climate impact studies using semantic technologies

    Science.gov (United States)

    Sinha, K.; Fox, P.; Raskin, R.; McGuinness, D.

    2008-05-01

    In support of a NASA-funded scientific application (SESDI; Semantically Enabled Science Data Integration Project; (http://sesdi.hao.ucar.edu/) that needs to share volcano and climate data to investigate statistical (e.g. height of the tropopause) relationships between volcanism and global climate, we have generated a volcano and plate tectonic ontologies and leveraged and re-factored the existing SWEET (Semantic Web for Earth and Environmental Terminology) ontoloy. To fulfil several goals we have developed set of packages for integrating the relevant ontologies (which are shared and reused by a broad community of users) to provide access to the key solid-earth (volcano) and atmospheric related databases. We present details on how ontologies are used in this science application setting, the methodologies employed to create the ontologies, register them to the underlying data and the implementation for use by scientists. SESDI is an NASA/ESTO/ACCESS-funded project involving the High Altitude Observatory at the National Center for Atmospheric Research (NCAR), McGuinness Associates Consulting, NASA/JPL and Virginia Polytechnic University.

  1. Impact of galactic cosmic rays on Earth’s atmosphere and human health

    Science.gov (United States)

    Singh, A. K.; Siingh, Devendraa; Singh, R. P.

    2011-07-01

    The galactic cosmic rays (GCRs) originating from astrophysical sources and traversing through the interstellar/interplanetary medium reach the terrestrial atmosphere and produce complex dynamic changes in it. The flow rate of GCRs incident on the Earth’s upper atmosphere is varied by the solar wind and the geomagnetic field. Striking correlations between the cloud cover and GCR fluxes on long time scale are observed whereas on short time scale no significant correlation is found. These observations are directly related to climate variations on short term as well as long term. In the present paper, we have reviewed and attempted to provide an overview of cosmic ray effects on terrestrial processes such as electrical phenomena, lightning discharges cloud formation and cloud coverage, temperature variation, space weather phenomena, Earth’s climate and the effects of GCRs on human health. It is shown that CRs control long term variations of some of the above mentioned physical processes, which in turn control short term and long term variations in climate. It is also pointed out that there are many basic phenomena which need further study and require new and long term data set.

  2. Impact of Atmospheric Attenuations Time Resolutions in Solar Radiation Derived from Satellite Imagery

    Science.gov (United States)

    Cony, Marco; Liria, Juan; Weisenberg, Ralf; Serrano, Enrique

    2014-05-01

    Accurate knowledge of solar irradiance components at the earth surface is of highly interest in many scientific and technology branches concerning meteorology, climate, agriculture and solar energy applications. In the specific case of solar energy systems the solar resource analysis with accuracy is a first step in every project since it is a required data for design, power output estimations, systems simulations and risk assessments. Solar radiation measurement availability is increasing both in spatial density and in historical archiving. However, it is still quite limited and most of the situations cannot make use of a long term ground database of high quality since solar irradiance is not generally measured where users need data. Satellite-derived solar radiation estimations are a powerful and valuable tool for solar resource assessment studies that have achieved a relatively high maturity due to years of developments and improvements. However, several sources of uncertainty are still present in satellite-derived methods. In particular, the strong influence of atmospheric attenuation information as input to the method is one of the main topics of improvement. Since solar radiation attenuation by atmospheric aerosols, and water vapor in a second place, is, after clouds, the second most important factor determining solar radiation, and particularly direct normal irradiance, the accurate knowledge of aerosol optical depth and water vapor content is relevant in the final output of satellite-derived methods. This present work, two different datasets we are used for extract atmospheric attenuation information. On the one hand the monthly mean values of the Linke turbidity factor from Meteotest database, which are twelve unique values of the Linke turbidity worldwide with a spatial resolution of 1/12º. On the other hand, daily values of AOD (Aerosol Optical Depth) at 550 nm, Angstrom alpha exponent and water vapor column were taken from a gridded database that

  3. Impacts of atmospheric pollution on the plant communities of British acid grasslands

    Energy Technology Data Exchange (ETDEWEB)

    Payne, Richard J., E-mail: r.payne@mmu.ac.uk [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Geography, School of Environment and Development, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Stevens, Carly J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ (United Kingdom); Dise, Nancy B. [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Gowing, David J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Pilkington, Michael G.; Phoenix, Gareth K. [Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN (United Kingdom); Emmett, Bridget A. [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Ashmore, Michael R. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)

    2011-10-15

    Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent. - Highlights: > Ozone exposure, N and base cation deposition modify UK acid grassland composition. > Ozone influences community composition without reducing species richness. > Nitrogen and base cation deposition have interacting impacts. > Distinct species responses to pollutants suggest potential for bioindication. - Ozone exposure and nitrogen deposition have distinct but additive impacts on the plant communities of British acid grasslands.

  4. Effects of Plastic Box Modified Atmosphere Storage on the Antioxidant System of Fresh-cut Fuji Apple%箱式气调贮藏对鲜切富士苹果抗氧化系统的影响

    Institute of Scientific and Technical Information of China (English)

    姜爱丽; 胡文忠; 代喆; 田密霞; 刘程惠

    2011-01-01

    以富士苹果为试材,研究了鲜切富士苹果在5℃的5%O2+5%CO:或5%02+10%CO2箱式气调贮藏条件下抗氧化系统的变化情况。每3d测定1次酶促防御系统的酶活性和非酶促防御系统的抗氧化物质的含量,并测定呼吸速率、腐烂率和褐交情况。结果表明:与对照相比,2种CO2浓度的箱武气调贮藏条件均可启动酶促防御系统,使过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性得到提高,同时也加速了非酶促防御系统抗氧化物质的消耗,降低了总酚和Vc含量以及贮藏中后期的还原型谷胱甘肽(GSH)含量。2种浓度的CO2处理可有效减慢呼吸速率,抑制腐烂的发生并有效降低褐变程度,其中5%0:+5%CO2更有利于鲜切富士苹果褐交的控制,而5%0,+10%CO2更有利于抑制腐烂。%In order to determine the effects of plastic box modified atmosphere storage on the antioxidant system of fresh-cut Fuji apple, the condition of 5% 02 +5% C02 and 5% 02 + 10% CO= atmosphere at 5℃ were established in this experiment. Meanwhile, the activity of enzymatic defense system, the concentration of non - enzyme antioxidants as well as respiration rate, rot rate and browning degree were measured every 3 d. The results indicated that two kinds of plastic box modified atmosphere with high CO2 were all able to start the enzymatic defense system. There- fore, not only the peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) activities were increased, but the consumption of antioxidant in non-enzymatic defense system were also accelerate. The total phenolics, Vc and reduced glutathione (GSH) content were decreased. Moreover, 5 % 02 + 5 % CO2 and 5 % 02 +10 % C02 effectively slowed down the respiration rate, inhibited the occurrence of decay and reduced the degree of browning. Apples stored with 5 % 02 +5 % CO2 was better in

  5. The impact of pollutants on the antioxidant protection of species of the genus Tilia at different developmental stages

    Directory of Open Access Journals (Sweden)

    A. A. Alexeyeva

    2016-03-01

    Full Text Available The influence of transport fumes and industrial waste on the activity of catalase, benzidine-peroxidase and guaiacol-peroxidase was studied in the dormant buds, leaves and seeds of the following species of the genus Tilia:T. platyphyllos Scop., T. europaea L., T. amurensis Rupr. and T. begoniifolia Stev. We tested the hypothesis that the action of pollutants changes the state of antioxidant protection at different stages of tree development in contaminated phytocenoses. An increase in catalase activity was observed in leaves of all linden species, and the action of transport fumes caused excess over control level by 118, 118, 196, and 61% respectively for T. platyphyllos, T. europaea, T. amurensis and T. begoniifolia. The action of industrial waste was accompanied by a slight decrease in catalase activity in T. europaea leaves, and increase in activity in leaves of T. amurensis and T. begoniifolia (143% and 115%. Benzidine-peroxidase activity increased due to the influence of transport fumes on leaves of T. amurensis and T. begoniifolia (103% and 44%, but decreased due to the effect of industrial waste on leaves of T. europaea, T. amurensis and T. begoniifolia (46%, 30%, and 44% respectively, and was suppressed in the seeds of T. europaea, T. amurensis and T. begoniifolia both under the influence of transport (42%, 47% and 33% below control and industrial emissions (19%, 19% and 45%, and was reduced in buds of T. platyphyllos, T. europaea and T. amurensis due to the effect of transport fumes (21%, 9% and 20% respectively. Guaiacol-peroxidase activity decreased due to the influence of transport fumes in buds of T. platyphyllos, T. europaea and T. amurensis (41%, 14% and 47% below control, while it increased in the seeds of T. platyphyllos and T. amurensis (104% and 83%, as well as in leaves of T. amurensis and T. begoniifolia both due to the effect of transport (129% and 144% and of industrial emissions (respectively, 34% and 40% above control

  6. Computer simulations of large asteroid impacts into oceanic and continental sites--preliminary results on atmospheric, cratering and ejecta dynamics

    Science.gov (United States)

    Roddy, D.J.; Schuster, S.H.; Rosenblatt, M.; Grant, L.B.; Hassig, P.J.; Kreyenhagen, K.N.

    1987-01-01

    Computer simulations have been completed that describe passage of a 10-km-diameter asteroid through the Earth's atmosphere and the subsequent cratering and ejecta dynamics caused by impact of the asteroid into both oceanic and continental sites. The asteroid was modeled as a spherical body moving vertically at 20 km/s with a kinetic energy of 2.6 ?? 1030 ergs (6.2 ?? 107 Mt ). Detailed material modeling of the asteroid, ocean, crustal units, sedimentary unit, and mantle included effects of strength and fracturing, generic asteroid and rock properties, porosity, saturation, lithostatic stresses, and geothermal contributions, each selected to simulate impact and geologic conditions that were as realistic as possible. Calculation of the passage of the asteroid through a U.S. Standard Atmosphere showed development of a strong bow shock wave followed by a highly shock compressed and heated air mass. Rapid expansion of this shocked air created a large low-density region that also expanded away from the impact area. Shock temperatures in air reached ???20,000 K near the surface of the uplifting crater rim and were as high as ???2000 K at more than 30 km range and 10 km altitude. Calculations to 30 s showed that the shock fronts in the air and in most of the expanding shocked air mass preceded the formation of the crater, ejecta, and rim uplift and did not interact with them. As cratering developed, uplifted rim and target material were ejected into the very low density, shock-heated air immediately above the forming crater, and complex interactions could be expected. Calculations of the impact events showed equally dramatic effects on the oceanic and continental targets through an interval of 120 s. Despite geologic differences in the targets, both cratering events developed comparable dynamic flow fields and by ???29 s had formed similar-sized transient craters ???39 km deep and ???62 km across. Transient-rim uplift of ocean and crust reached a maximum altitude of nearly

  7. Non-linear Ice Sheet influence during deglaciation and its impact on the evolution of atmospheric teleconnection patterns

    Science.gov (United States)

    Dietrich, Stephan; Wassenburg, Jasper; Wei, Wei; Lohmann, Gerrit; Jens, Fohlmeister; Adrian, Immenhauser

    2013-04-01

    During present conditions atmospheric teleconnections such as the Arctic Oscillation/North Atlantic Oscillation (AO/NAO) have a major impact on Northern Hemispheric climate. However, the Early Holocene is characterized by the presence and melting of the Laurentide Ice Sheet (LIS) leading to a different background climate in comparison to today. Here we investigate the climate evolution during the early (9 ka BP, including LIS and melt water), mid (6 ka BP) and late Holocene (pre-industrial conditions) focussing on the mechanisms and feedbacks during deglaciation by applying the state-of-the-art earth system model COSMOS. A special interest is set on the evolution of atmospheric teleconnection patterns such as the AO/NAO and the Atlantic Multidecadal Oscillation (AMO) that have a major influence on North Atlantic/European climate. The evolution and relative importance of these oscillations throughout the Holocene, however, is still largely unknown. We demonstrate that North Atlantic/European climate is affected by a shift from a more ocean-ice-dominated climate during approx. 9 ka towards a more atmosphere-dominated one during the mid to late Holocene. To isolate the contributions of the presence of the LIS and the melt water we run four different model simulations for the early Holocene sensitivity study (a standard configuration only forced with green house gases and orbital parameters, one with the additional LIS topography, one with a melt water flux of 0.09 Sv, and a fourth that combines all the external forcings). The model results show that the influence of the LIS and its melt water contribution lead to a strong non-linear cooling of surface air temperatures during deglaciation. This synergetic influence of the Laurentide Ice Sheet strengthens the effect of melting on ocean circulation during the early Holocene. The severe colder background climate during deglaciation leads to a more vulnerable ocean circulation in terms of the Atlantic Meridional

  8. Das antioxidative Potential der Haut

    OpenAIRE

    Jung, Sora

    2014-01-01

    Background: Antioxidants represent an important protective mechanism against the destructive effects of free radicals in the human organism. These can arise due to various internal and external influences, such as UV and infrared radiation, chemical toxicants, infectious diseases or nicotine and alcohol abuse. The aim of this study was to investigate the impact of individual lifestyle habits, such as diet and stress factors, on the antioxidant status of the skin. Furthermore possible differen...

  9. Impacts of changing atmospheric deposition chemistry on nitrogen and phosphorus loading to Ganga River (India).

    Science.gov (United States)

    Pandey, Jitendra; Singh, Anand V; Singh, Ashima; Singh, Rachna

    2013-08-01

    Investigations on atmospheric deposition (AD) and water chemistry along a 35 km stretch of Ganga River indicated that although N:P stoichiometry of AD did not change, there were over 1.4-2.0 fold increase in AD-NO₃⁻, AD-NH₄⁺ and AD-PO₄³⁻ overtime. Concentration of dissolved inorganic-N (DIN) in river showed significant positive correlations with AD-NO₃⁻ and runoff DIN. Similarly, dissolved reactive-P (DRP) in river showed significant positive correlation with AD-PO₄³⁻ and runoff DRP. The study shows that AD has become an important source of N and P input to Ganga River.

  10. Impacts of changing atmospheric deposition chemistry on nitrogen and phosphorus loading to Ganga River (India).

    Science.gov (United States)

    Pandey, Jitendra; Singh, Anand V; Singh, Ashima; Singh, Rachna

    2013-08-01

    Investigations on atmospheric deposition (AD) and water chemistry along a 35 km stretch of Ganga River indicated that although N:P stoichiometry of AD did not change, there were over 1.4-2.0 fold increase in AD-NO₃⁻, AD-NH₄⁺ and AD-PO₄³⁻ overtime. Concentration of dissolved inorganic-N (DIN) in river showed significant positive correlations with AD-NO₃⁻ and runoff DIN. Similarly, dissolved reactive-P (DRP) in river showed significant positive correlation with AD-PO₄³⁻ and runoff DRP. The study shows that AD has become an important source of N and P input to Ganga River. PMID:23700007

  11. Potential impact of rising atmospheric CO2 on quality of grains in chickpea (Cicer arietinum L.).

    Science.gov (United States)

    Saha, Saurav; Chakraborty, Debashis; Sehgal, Vinay K; Pal, Madan

    2015-11-15

    Experiments were conducted in open-top chambers to assess the effect of atmospheric CO2 enrichment (E-CO2) on the quality of grains in chickpea (Cicer arietinum L.) crop. Physical attributes of the grains was not affected, but the hydration and swelling capacities of the flour increased. Increase in carbohydrates and reduction in protein made the grains more carbonaceous (higher C:N) under E-CO2. Among other mineral nutrients, K, Ca and Zn concentrations decreased, while P, Mg, Cu, Fe, Mn and B concentrations did not change. The pH, bulk density and cooking time of chickpea flour remained unaffected, although the water absorption capacity of flour increased and oil absorption reduced. Results suggest that E-CO2 could affect the grain quality adversely and nutritional imbalance in grains of chickpea might occur.

  12. Observed impacts of duration and seasonality of atmospheric-river landfalls on soil moisture and runoff in coastal northern California

    Science.gov (United States)

    Ralph, F.M.; Coleman, T.; Neiman, P.J.; Zamora, R.J.; Dettinger, Mike

    2013-01-01

    This study is motivated by diverse needs for better forecasts of extreme precipitation and floods. It is enabled by unique hourly observations collected over six years near California’s Russian River and by recent advances in the science of atmospheric rivers (ARs). This study fills key gaps limiting the prediction of ARs and, especially, their impacts by quantifying the duration of AR conditions and the role of duration in modulating hydrometeorological impacts. Precursor soil moisture conditions and their relationship to streamflow are also shown. On the basis of 91 well-observed events during 2004-10, the study shows that the passage of ARs over a coastal site lasted 20 h on average and that 12% of the AR events exceeded 30 h. Differences in storm-total water vapor transport directed up the mountain slope contribute 74% of the variance in storm-total rainfall across the events and 61% of the variance in storm-total runoff volume. ARs with double the composite mean duration produced nearly 6 times greater peak streamflow and more than 7 times the storm-total runoff volume. When precursor soil moisture was less than 20%, even heavy rainfall did not lead to significant streamflow. Predicting which AR events are likely to produce extreme impacts on precipitation and runoff requires accurate prediction of AR duration at landfall and observations of precursor soil moisture conditions.

  13. Impact of atmospheric effects in free-space optics transmission systems

    Science.gov (United States)

    Leitgeb, Erich; Gebhart, M.; Fasser, Peter; Bregenzer, Josef; Tanczos, J.

    2003-04-01

    The coherent wave propagation is affected by the atmosphere in many ways. Several theoretical models for propagation of light through the atmosphere are well known. To predict link availability in different climate zones it is necessary to do field tests for data acquisition. Therefore we have done reliability- and availability-tests on commercial available and also on self-developed optical point-to-point and point-to-multipoint systems. We sent test data at 155 Mbps (STM-1) from one FSO-unit to a distant (2.7 km) FSO-unit. The received data were sent back (loop) to the first unit. Our primary interest in this long-time investigation was the time of link failure, because it turned out that BERs be low in general, less than 10-8 at very bad weather conditions in winter and less than 10-12 at clear sky. In a second measurement campaign we investigated the influence of turbulences in the air. The measurements clearly show variations in the fluctuation of the incoming optical power during a day. In principle there are two periods with strong variations, during the day and during the night, and two periods of rather stable air, these are around sunset and sunrise. The power variations have the highest amplitude and show the fastest changes at noon and they are less distinct and show slower changes in the night. As a medium value we got power variations of 4 dB over the distance of 2.7 km in summer. The duration of fades/scintillations was in the order of 4 to 60 milliseconds at daytime and about 10 to 150 ms in the night.

  14. Historical detection of atmospheric impacts by large bolides using acoustic-gravity waves

    Energy Technology Data Exchange (ETDEWEB)

    ReVelle, D.O.

    1995-05-01

    During the period from about 1960 to the early 1980`s a number of large bolides (meteor-fireballs) entered the atmosphere which were sufficiently large to generate blast waves during their drag interaction with the air. For example, the remnant of the blast wave from a single kiloton class event was subsequently detected by up to six ground arrays of microbarographs which were operated by the U.S. Air Force during this pre-satellite period. Data have also been obtained from other sources during this period as well and are also discussed in this summary of the historical data. The Air Force data have been analyzed in terms of their observable properties in order to infer the influx rate of NEO`s (near-Earth objects) in the energy range from 0.2 to 1100 kt. The determined influx is in reasonable agreement with that determined by other methods currently available such as Rabinowitz (1992), Ceplecha, (1992; 1994b) and by Chapman and Morrison (1994) despite the fact that due to sampling deficiencies only a portion of the {open_quotes}true{close_quotes} flux of large bodies has been obtained by this method, i.e., only sources at relatively low elevations have been detected. Thus the weak, fragile cometary bodies which do not penetrate the atmosphere as deeply are less likely to have been sampled by this type of detection system. Future work using the proposed C.T.B.T. (Comprehensive Test Ban Treaty) global scale infrasonic network will be likely to improve upon this early estimate of the global influx of NEO`s considerably.

  15. Experimental study of the impact of large-scale wind farms on land–atmosphere exchanges

    International Nuclear Information System (INIS)

    Large-scale wind farms, covering a significant portion of the land and ocean surface, may affect the transport of momentum, heat, mass and moisture between the atmosphere and the land locally and globally. To understand the wind-farm–atmosphere interaction, we conducted wind-tunnel experiments to study the surface scalar (heat) flux using model wind farms, consisting of more than ten rows of wind turbines—having typical streamwise and spanwise spacings of five and four rotor diameters—in a neutral boundary layer with a heated surface. The spatial distribution of the surface heat flux was mapped with an array of surface heat flux sensors within the quasi-developed regime of the wind-farm flow. Although the overall surface heat flux change produced by the wind farms was found to be small, with a net reduction of 4% for a staggered wind farm and nearly zero change for an aligned wind farm, the highly heterogeneous spatial distribution of the surface heat flux, dependent on the wind-farm layout, was significant. The difference between the minimum and maximum surface heat fluxes could be up to 12% and 7% in aligned and staggered wind farms, respectively. This finding is important for planning intensive agriculture practice and optimizing farm land use strategy regarding wind energy project development. The well-controlled wind-tunnel experiments presented in this study also provide a first comprehensive dataset on turbulent flow and scalar transport in wind farms, which can be further used to develop and validate new parameterizations of surface scalar fluxes in numerical models. (letter)

  16. Impact of atmospheric circulations on aerosol distributions in autumn over eastern China: observational evidence

    Science.gov (United States)

    Zheng, X. Y.; Fu, Y. F.; Yang, Y. J.; Liu, G. S.

    2015-11-01

    Regional heavy pollution events in eastern China (110-122° E, 28-40° N) are causing serious environmental problems. In this study, the relationship between the degree of regional pollution and the patterns of large-scale atmospheric circulation over eastern China in October is investigated using 10-year (2001-2010) Terra/MODIS aerosol optical depth and NCEP reanalysis data by both case study and composite analysis. Eighteen polluted and 10 clean episodes are selected and categorised into six polluted types and three clean types respectively. Generally speaking, weather patterns such as a uniform surface pressure field in eastern China or a steady straight westerly in the middle troposphere, particularly when being at the rear of the anticyclone at 850 hPa, are typically responsible for heavy pollution events. Meanwhile, clean episodes occur when strong southeastward cold air advection prevails below the middle troposphere or air masses are transported from sea to land. Uniform descending motion prevails over the study region, trapping pollutants in the lower atmosphere. Therefore, the value of vertical velocity averaged from 1000 to 100 hPa and divergence of wind field in the lower troposphere are used in this study to quantify the diffusion conditions in each circulation type. The results reveal that it is often a clean episode when both the mean downward motion (larger than 2.56 × 10-2 Pa s-1) and the divergence of low-level winds (larger than 1.79 × 10-2 s-1) are strong. Otherwise, it is more likely to be a polluted episode.

  17. Impact of pregnancy and nutrition on oxidant⁄antioxidant balance in sheep and goats reared in South Sinai, Egypt

    Directory of Open Access Journals (Sweden)

    M. F. Nawito

    2016-08-01

    Full Text Available Aim: To monitor the effect of nutrition and pregnancy on oxidative status of animals under the arid condition of South Sinai. Materials and Methods: Blood samples were taken from two groups of animals: The first group retained in farm and fed on concentrate (high diet and another group grazing natural forage (low diet. Each group was subdivided into pregnant and non-pregnant animals. Blood samples were assayed for their content of malondialdehyde (MDA, total antioxidant capacity (TAC, catalase (CAT, and superoxide dismutase (SOD enzymes. Results: MDA level significantly increased in pregnant animals fed either concentrate or grazing low-quality forage and accompanied by a low level of TAC in pregnant grazing animals fed low-quality forage. The activity of CAT decreased in pregnant fed either concentrate or grazing and SOD significant decrease in the pregnant grazing group. These data suggested that the animals might have experienced some degree of oxidative stress and lipid peroxidation and indicating that redox homeostasis was impaired in those pregnant and specially fed on forage rations. Conclusion: Pregnancy constituted the most oxidative stress facing the grazing and concentrated diet feed sheep and goats under arid and saline conditions of Southern Sinai, Egypt.

  18. Possible Impact of Antioxidant Properties of Cocoa (Theobroma Cacao L.) Against Irradiation - Induced Some Biochemical Disorders in Rats

    International Nuclear Information System (INIS)

    Man is exposed to natural radiations either from cosmic or terrestrial origins. Furthermore, it is well known that the gamma irradiation of animals induce biochemical alterations which depend mostly on oxidative stress. This work aimed at evaluating the radioprotective efficiency of Cocoa (Theobroma cacao L.) against whole body γ-irradiation of rats. The virtue of cocoa aqueous extract (CAE) was given to rats at a dose of 1 g/ kg for 6 weeks to determine changes in hepatic marker enzymes, lipid profile and antioxidant status. The animals exposed to γ-rays exhibited a pronounced increment in serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and gamma glutamyl transpeptidase (γ GT), total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and liver thiobarbituric acid reactive substance (TBARS). On the other hand, a significant decline was demonstrated in high density lipoprotein cholesterol (HDL-C). A decrease of hepatic reduced glutathione (GSH) content, superoxides dismutase (SOD) and catalase (CAT) activities was sustained. The CAE administered orally to rats has significantly modulated all the radiation-induced biochemical alterations. These findings revealed that cocoa would exert radio-protective properties

  19. Postexercise Impact of Ice-Cold Water Bath on the Oxidant-Antioxidant Balance in Healthy Men

    Directory of Open Access Journals (Sweden)

    Paweł Sutkowy

    2015-01-01

    Full Text Available The aim of the study was to determine the effect of a 5 min head-out ice-cold water bath on the oxidant-antioxidant balance in response to exercise. The crossover study included the subjects (n=24; aged 28.7±7.3 years who performed two identical stationary cycling bouts for 30 min and recovered for 10 min at room temperature (RT=20°C; session 1 or in a pool with ice-cold water (ICW=3°C, 5 min immersion; session 2. The concentration of thiobarbituric acid reactive substances (TBARS in blood plasma (TBARSpl and erythrocytes (TBARSer and the erythrocytic activity of superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx were measured three times during each of the two study sessions: before the exercise (baseline and 20 and 40 min after the appropriate recovery session. Lower concentration of TBARSpl 40 min after postexercise recovery in ICW was revealed as compared with that after recovery at RT (P<0.05. Moreover, a statistically significant postexercise increase in the TBARSpl and TBARSer concentrations was found (P<0.01 and P<0.05, resp.. A short-term ice-cold water bath decreases postexercise lipid peroxidation.

  20. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    Science.gov (United States)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  1. External costs of atmospheric Pb emissions: valuation of neurotoxic impacts due to inhalation

    Directory of Open Access Journals (Sweden)

    Frohn Lise

    2010-02-01

    Full Text Available Abstract Background The Impact Pathway Approach (IPA is an innovative methodology to establish links between emissions, related impacts and monetary estimates. Only few attempts have so far been presented regarding emissions of metals; in this study the external costs of airborne lead (Pb emissions are assessed using the IPA. Exposure to Pb is known to provoke impacts especially on children's cognition. As cognitive abilities (measured as IQ, intelligence quotient are known to have implications for lifetime income, a pathway can be established leading from figures for Pb emissions to the implied loss in earnings, and on this basis damage costs per unit of Pb emission can be assessed. Methods Different types of models are here linked. It is relatively straightforward to establish the relationship between Pb emissions and consequent increase in air-Pb concentration, by means of a Gaussian plume dispersion model (OML. The exposed population can then be modelled by linking the OML-output to population data nested in geo-referenced grid cells. Less straightforward is to establish the relationship between exposure to air-Pb concentrations and the resulting blood-Pb concentration. Here an Age-Dependent Biokinetic Model (ADBM for Pb is applied. On basis of previous research which established links between increases in blood-Pb concentrations during childhood and resulting IQ-loss we arrive at our results. Results External costs of Pb airborne emissions, even at low doses, in our site are in the range of 41-83 €/kg emitted Pb, depending on the considered meteorological year. This estimate applies only to the initial effects of air-Pb, as our study does not address the effects due to the Pb environmental-accumulation and to the subsequent Pb re-exposure. These are likely to be between one and two orders of magnitude higher. Conclusions Biokinetic modelling is a novel tool not previously included when applying the IPA to explore impacts of Pb emissions

  2. Degradation of metaflumizone in soil: impact of varying moisture, light, temperature, atmospheric CO2 level, soil type and soil sterilization.

    Science.gov (United States)

    Chatterjee, Niladri Sekhar; Gupta, Suman; Varghese, Eldho

    2013-01-01

    Soil is a major sink for the bulk of globally used pesticides. Hence, fate of pesticides in soil under the influence of various biotic and abiotic factors becomes important for evaluation of stability and safety. This paper presents the impact of varying moisture, light, temperature, atmospheric CO(2) level, soil type and soil sterilization on degradation of metaflumizone, a newly registered insecticide in India. Degradation of metaflumizone in soil followed the first order reaction kinetics and its half life values varied from ~20 to 150 d. Under anaerobic condition, degradation of metaflumizone was faster (t(½) 33.4 d) compared to aerobic condition (t(½) 50.1 d) and dry soil (t(½) 150.4 d). Under different light exposures, degradation was the fastest under UV light (t(½) 27.3 d) followed by Xenon light (t(½) 43 d) and dark condition (t(½) 50.1 d). Degradation rate of metaflumizone increased with temperature and its half life values ranged from 30.1 to 100.3d. Elevated atmospheric CO(2) level increased the degradation in soil (t(½) 20.1-50.1 d). However, overall degradation rate was the fastest at 550 ppm atmospheric CO(2) level, followed by 750 ppm and ambient level (375 ppm). Degradation of metaflumizone was faster in Oxisol (pH 5.2, Total Organic Carbon 1.2%) compared to Inceptisol (pH 8.15, TOC 0.36%). In sterile soil, only 5% dissipation of initial concentration was observed after 90 d of sampling. Under various conditions, 4-cyanobenzoic acid (0.22-1.86 mg kg(-1)) and 4-trifluoromethoxy aniline (0.21-1.23 mg kg(-1)) were detected as major degradation products.

  3. Evaluation of the impact of atmospheric ozone and aerosols on the horizontal global/diffuse UV Index at Livorno (Italy)

    Science.gov (United States)

    Scaglione, Daniele; Giulietti, Danilo; Morelli, Marco

    2016-08-01

    A study was conducted at Livorno (Italy) to evaluate the impact of atmospheric aerosols and ozone on the solar UV radiation and its diffuse component at ground in clear sky conditions. Solar UV radiation has been quantified in terms of UV Index (UVI), following the ISO 17166:1999/CIE S007/E-1998 international standard. UVI has been calculated by exploiting the libRadtran radiative transfer modelling software as a function of both the Aerosols Optical Depth (AOD) and the Total Ozone Column (TOC). In particular AOD and TOC values have been remotely sensed by the Ozone Monitoring Instrument (OMI) on board the NASA's EOS (Earth Observing System) satellites constellation. An experimental confirmation was also obtained by exploiting global UVI ground-based measurements from the 26/9/14 to 12/8/15 and diffuse UVI ground-based measurements from the 17/5/15 to 12/8/15. For every considered value of Solar Zenith Angle (SZA) and atmospheric condition, estimates and measurements confirm that the diffuse component contributes for more than 50% on the global UV radiation. Therefore an exposure of human skin also to diffuse solar UV radiation can be potentially harmful for health and need to be accurately monitored, e.g. by exploiting innovative applications such as a mobile app with a satellite-based UV dosimeter that has been developed. Global and diffuse UVI variations due to the atmosphere are primarily caused by the TOC variations (typically cyclic): the maximum TOC variation detected by OMI in the area under study leads to a corresponding variation in global and diffuse UVI of about 50%. Aerosols in the area concerned, mainly of maritime nature, have instead weaker effects causing a maximum variation of the global and diffuse UVI respectively of 9% and 35% with an SZA of 20° and respectively of 13% and 10% with an SZA of 60°.

  4. Sensitivity studies on the photolysis rates calculation in Amazonian atmospheric chemistry ? Part I: The impact of the direct radiative effect of biomass burning aerosol particles

    OpenAIRE

    Albuquerque, L. M. M.; Longo, K. M.; S. R. Freitas; Tarasova, T.; Plana Fattori, A.; Nobre, C.; Gatti, L. V.

    2005-01-01

    International audience The impact of the direct radiative effect of the aerosol particles on the calculation of the photolysis rates and consequently on the atmospheric chemistry in regional smoke clouds due to biomass burning over the Amazon basin is addressed in this work. It explores a case study for 19 September 2002 at LBA-RACCI-SMOCC (The Large-Scale Biosphere-Atmosphere experiment in Amazonia ? Radiation, Cloud, and Climate Interactions ? Smoke, Aerosols, Clouds, Rainfall and Climat...

  5. The impact of SST biases on projections of anthropogenic climate change: A greater role for atmosphere-only models?

    Science.gov (United States)

    He, Jie; Soden, Brian J.

    2016-07-01

    There is large uncertainty in the model simulation of regional climate change from anthropogenic forcing. Recent studies have tried to link such uncertainty to intermodel differences in the pattern of sea surface temperature (SST) change. On the other hand, coupled climate models also contain systematic biases in their climatology, largely due to drift in SSTs. To the extent that the projected changes depend on the mean state, biases in the present-day climatology also contribute to the intermodel spread in climate change projections. By comparing atmospheric general circulation model (AGCM) simulations using the climatological SSTs from different coupled models, we show that biases in the climatological SST generally have a larger impact on regional projections over land than do intermodel differences in the pattern of SST change. These results advocate for a greater application of AGCM simulations with observed SSTs or flux-adjusted coupled models to improve regional projections of anthropogenic climate change.

  6. Using Coupled Subsurface-Atmospheric Simulations to Investigate the Impact of Irrigation on Atmospheric Response in the San Joaquin River Basin, California

    Science.gov (United States)

    Gilbert, J. M.; Maxwell, R. M.; Gochis, D. J.; Maples, S.; Markovich, K. H.

    2015-12-01

    Observational and modeling studies are continually improving our understanding of terrestrial and atmospheric process interactions over natural and managed systems. Recent studies have implicated irrigation as a strong factor in perturbing land-atmosphere coupling, although the details of this interaction are not fully characterized. Therefore, in this study we seek to better understand the role of subsurface flow under conditions of groundwater extraction and irrigation on resulting atmospheric states. We use an ensemble of coupled ParFlow-WRF simulations over the San Joaquin River Basin in California to identify the type and character of land-atmosphere interactions for a set of irrigation scenarios. Ensemble members include selected boundary layer schemes, land surface model configurations, and initial and boundary condition perturbations. Variability in atmospheric response, particularly in boundary layer height and precipitation patterns, under high water table (characteristic of predevelopment conditions) and lowered water table (resulting from historic groundwater extraction) conditions are evaluated in the context of the uncertainty resulting from choice of model physics and atmospheric perturbations. Hydrologic alterations associated with lowered water table elevation appear linked to the atmosphere via changes in boundary layer height.

  7. Impacts of land surface properties and atmospheric CO2 on the Last Glacial Maximum climate: a factor separation analysis

    Directory of Open Access Journals (Sweden)

    G. Munhoven

    2009-06-01

    Full Text Available Many sensitivity studies have been carried out, using climate models of different degrees of complexity to test the climate response to Last Glacial Maximum boundary conditions. Here, instead of adding the forcings successively as in most previous studies, we applied the separation method of U. Stein et P. Alpert 1993, in order to determine rigorously the different contributions of the boundary condition modifications, and isolate the pure contributions from the interactions among the forcings. We carried out a series of sensitivity experiments with the model of intermediate complexity Planet Simulator, investigating the contributions of the ice sheet expansion and elevation, the lowering of the atmospheric CO2 and of the vegetation cover change on the LGM climate. The separation of the ice cover and orographic contributions shows that the ice albedo effect is the main contributor to the cooling of the Northern Hemisphere, whereas orography has only a local cooling impact over the ice sheets. The expansion of ice cover in the Northern Hemisphere causes a disruption of the tropical precipitation, and a southward shift of the ITCZ. The orographic forcing mainly contributes to the disruption of the atmospheric circulation in the Northern Hemisphere, leading to a redistribution of the precipitation, but weakly impacts the tropics. The isolated vegetation contribution also induces strong cooling over the continents of the Northern Hemisphere that further affects the tropical precipitation and reinforce the southward shift of the ITCZ, when combined with the ice forcing. The combinations of the forcings generate many non-linear interactions that reinforce or weaken the pure contributions, depending on the climatic mechanism involved, but they are generally weaker than the pure contributions. Finally, the comparison between the LGM simulated climate and climatic reconstructions over Eurasia suggests that our results reproduce well the south-west to

  8. A study of the impact of land-use change in Borneo on atmospheric composition using a global model

    Directory of Open Access Journals (Sweden)

    N. J. Warwick

    2013-03-01

    Full Text Available In this study, we use a high resolution version of the Cambridge p-TOMCAT model, along with data collected during the 2008 NERC-funded Oxidant and Particle Photochemical Processes (OP3 project, to examine the potential impact of the expansion of oil palm in Borneo on air quality and atmospheric composition. Several model emission scenarios are run for the OP3 measurement period, incorporating emissions from both global datasets and local flux measurements. Isoprene fluxes observed at a forest site during OP3 were considerably less than fluxes calculated using the MEGAN model. Incorporating the observed isoprene fluxes into p-TOMCAT substantially improved the comparison between modelled and observed isoprene surface mixing ratios and OH concentrations relative to using the MEGAN emissions. If both observed isoprene fluxes and HOx recycling chemistry were included, the ability of the model to capture diurnal variations in isoprene and OH was further improved. However, a similar improvement was also achieved using a~standard chemical mechanism without HOx recycling, by fixing boundary layer isoprene concentrations over Borneo to follow the OP3 observations. Further model simulations, considering an extreme scenario with all of Borneo converted to oil palm plantation, were run to determine the maximum atmospheric impact of land use change in Borneo. In these simulations, the level of nitrogen oxides was found to be critical. If only isoprene emissions from oil palm are considered, then large scale conversion to oil palm produced a decrease in monthly mean surface ozone of up to ~20%. However, if related changes in NOx emissions from fertilisation, industrial processing and transport are also included then ozone increases of up to ~70% were calculated. Although the largest changes occurred locally, the model also calculated significant regional changes of O3, OH and other species downwind of Borneo and in the free troposphere.

  9. Chilling-related cell damage of apple (Malus × domestica Borkh.) fruit cortical tissue impacts antioxidant, lipid and phenolic metabolism.

    Science.gov (United States)

    Leisso, Rachel S; Buchanan, David A; Lee, Jinwook; Mattheis, James P; Sater, Chris; Hanrahan, Ines; Watkins, Christopher B; Gapper, Nigel; Johnston, Jason W; Schaffer, Robert J; Hertog, Maarten L A T M; Nicolaï, Bart M; Rudell, David R

    2015-02-01

    'Soggy breakdown' (SB) is an internal flesh disorder of 'Honeycrisp' apple (Malus × domestica Borkh.) fruit that occurs during low temperature storage. The disorder is a chilling injury (CI) in which visible symptoms typically appear after several weeks of storage, but information about the underlying metabolism associated with its induction and development is lacking. The metabolic profile of flesh tissue from wholly healthy fruit and brown and healthy tissues from fruit with SB was characterized using gas chromatography-mass spectrometry (GC-MS) and liquid chromatograph-mass spectrometry (LC-MS). Partial least squares discriminant analysis (PLS-DA) and correlation networks revealed correlation among ester volatile compounds by composition and differences in phytosterol, phenolic and putative triacylglycerides (TAGs) metabolism among the tissues. anova-simultaneous component analysis (ASCA) was used to test the significance of metabolic changes linked with tissue health status. ASCA-significant components included antioxidant compounds, TAGs, and phytosterol conjugates. Relative to entirely healthy tissues, elevated metabolite levels in symptomatic tissue included γ-amino butyric acid, glycerol, sitosteryl (6'-O-palmitoyl) β-d-glucoside and sitosteryl (6'-O-stearate) β-d-glucoside, and TAGs containing combinations of 16:0, 18:3, 18:2 and 18:1 fatty acids. Reduced metabolite levels in SB tissue included 5-caffeoyl quinate, β-carotene, catechin, epicatechin, α-tocopherol, violaxanthin and sitosteryl β-d glucoside. Pathway analysis indicated aspects of primary metabolism differed according to tissue condition, although differences in metabolites involved were more subtle than those of some secondary metabolites. The results implicate oxidative stress and membrane disruption processes in SB development and constitute a diagnostic metabolic profile for the disorder.

  10. Atmospheric ethanol in London and the potential impacts of future fuel formulations.

    Science.gov (United States)

    Dunmore, Rachel E; Whalley, Lisa K; Sherwen, Tomás; Evans, Mathew J; Heard, Dwayne E; Hopkins, James R; Lee, James D; Lewis, Alastair C; Lidster, Richard T; Rickard, Andrew R; Hamilton, Jacqueline F

    2016-07-18

    There is growing global consumption of non-fossil fuels such as ethanol made from renewable biomass. Previous studies have shown that one of the main air quality disadvantages of using ethanol blended fuels is a significant increase in the production of acetaldehyde, an unregulated and toxic pollutant. Most studies on the impacts of ethanol blended gasoline have been carried out in the US and Brazil, with much less focus on the UK and Europe. We report time resolved measurements of ethanol in London during the winter and summer of 2012. In both seasons the mean mixing ratio of ethanol was around 5 ppb, with maximum values over 30 ppb, making ethanol currently the most abundant VOC in London air. We identify a road transport related source, with 'rush-hour' peaks observed. Ethanol is strongly correlated with other road transport-related emissions, such as small aromatics and light alkanes, and has no relationship to summer biogenic emissions. To determine the impact of road transport-related ethanol emission on secondary species (i.e. acetaldehyde and ozone), we use both a chemically detailed box model (incorporating the Master Chemical Mechanism, MCM) and a global and nested regional scale chemical transport model (GEOS-Chem), on various processing time scales. Using the MCM model, only 16% of the modelled acetaldehyde was formed from ethanol oxidation. However, the model significantly underpredicts the total levels of acetaldehyde, indicating a missing primary emission source, that appears to be traffic-related. Further support for a primary emission source comes from the regional scale model simulations, where the observed concentrations of ethanol and acetaldehyde can only be reconciled with the inclusion of large primary emissions. Although only constrained by one set of observations, the regional modelling suggests a European ethanol source similar in magnitude to that of ethane (∼60 Gg per year) and greater than that of acetaldehyde (∼10 Gg per year). The

  11. Atmospheric ethanol in London and the potential impacts of future fuel formulations.

    Science.gov (United States)

    Dunmore, Rachel E; Whalley, Lisa K; Sherwen, Tomás; Evans, Mathew J; Heard, Dwayne E; Hopkins, James R; Lee, James D; Lewis, Alastair C; Lidster, Richard T; Rickard, Andrew R; Hamilton, Jacqueline F

    2016-07-18

    There is growing global consumption of non-fossil fuels such as ethanol made from renewable biomass. Previous studies have shown that one of the main air quality disadvantages of using ethanol blended fuels is a significant increase in the production of acetaldehyde, an unregulated and toxic pollutant. Most studies on the impacts of ethanol blended gasoline have been carried out in the US and Brazil, with much less focus on the UK and Europe. We report time resolved measurements of ethanol in London during the winter and summer of 2012. In both seasons the mean mixing ratio of ethanol was around 5 ppb, with maximum values over 30 ppb, making ethanol currently the most abundant VOC in London air. We identify a road transport related source, with 'rush-hour' peaks observed. Ethanol is strongly correlated with other road transport-related emissions, such as small aromatics and light alkanes, and has no relationship to summer biogenic emissions. To determine the impact of road transport-related ethanol emission on secondary species (i.e. acetaldehyde and ozone), we use both a chemically detailed box model (incorporating the Master Chemical Mechanism, MCM) and a global and nested regional scale chemical transport model (GEOS-Chem), on various processing time scales. Using the MCM model, only 16% of the modelled acetaldehyde was formed from ethanol oxidation. However, the model significantly underpredicts the total levels of acetaldehyde, indicating a missing primary emission source, that appears to be traffic-related. Further support for a primary emission source comes from the regional scale model simulations, where the observed concentrations of ethanol and acetaldehyde can only be reconciled with the inclusion of large primary emissions. Although only constrained by one set of observations, the regional modelling suggests a European ethanol source similar in magnitude to that of ethane (∼60 Gg per year) and greater than that of acetaldehyde (∼10 Gg per year). The

  12. MJO prediction skill, predictability, and teleconnection impacts in the Beijing Climate Center Atmospheric General Circulation Model

    Science.gov (United States)

    Wu, Jie; Ren, Hong-Li; Zuo, Jinqing; Zhao, Chongbo; Chen, Lijuan; Li, Qiaoping

    2016-09-01

    This study evaluates performance of Madden-Julian oscillation (MJO) prediction in the Beijing Climate Center Atmospheric General Circulation Model (BCC_AGCM2.2). By using the real-time multivariate MJO (RMM) indices, it is shown that the MJO prediction skill of BCC_AGCM2.2 extends to about 16-17 days before the bivariate anomaly correlation coefficient drops to 0.5 and the root-mean-square error increases to the level of the climatological prediction. The prediction skill showed a seasonal dependence, with the highest skill occurring in boreal autumn, and a phase dependence with higher skill for predictions initiated from phases 2-4. The results of the MJO predictability analysis showed that the upper bounds of the prediction skill can be extended to 26 days by using a single-member estimate, and to 42 days by using the ensemble-mean estimate, which also exhibited an initial amplitude and phase dependence. The observed relationship between the MJO and the North Atlantic Oscillation was accurately reproduced by BCC_AGCM2.2 for most initial phases of the MJO, accompanied with the Rossby wave trains in the Northern Hemisphere extratropics driven by MJO convection forcing. Overall, BCC_AGCM2.2 displayed a significant ability to predict the MJO and its teleconnections without interacting with the ocean, which provided a useful tool for fully extracting the predictability source of subseasonal prediction.

  13. The importance of plume rise on the concentrations and atmospheric impacts of biomass burning aerosol

    Science.gov (United States)

    Walter, Carolin; Freitas, Saulo R.; Kottmeier, Christoph; Kraut, Isabel; Rieger, Daniel; Vogel, Heike; Vogel, Bernhard

    2016-07-01

    We quantified the effects of the plume rise of biomass burning aerosol and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection layer in combination with a parametrization of the vertical distribution of the emissions outperforms approaches in which the plume heights are initially predefined. Approximately 30 % of the fires exceed the height of 2 km with a maximum height of 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated aerosol optical depth (AOD) with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning aerosol with CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.

  14. Formation of aqueous-phase α-hydroxyhydroperoxides (α-HHP: potential atmospheric impacts

    Directory of Open Access Journals (Sweden)

    R. Zhao

    2013-06-01

    Full Text Available The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs via reversible nucleophilic addition of H2O2 to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity. Specifically, the equilibrium constants of α-HHP formation have been determined using proton nuclear-magnetic-resonance (1H NMR spectroscopy and proton-transfer-reaction mass spectrometry (PTR-MS. Significant α-HHP formation was observed from formaldehyde, acetaldehyde, propionaldehyde, glycolaldehyde, glyoxylic acid, and methylglyoxal, but not from methacrolein and ketones. Low temperatures enhanced the formation of α-HHPs but slowed their formation rates. High inorganic salt concentrations shifted the equilibria toward the hydrated form of the aldehydes and slightly suppressed α-HHP formation. Using the experimental equilibrium constants, we predict the equilibrium concentration of α-HHPs to be in the μM level in cloud water, but it may also be present in the mM level in aerosol liquid water (ALW, where the concentrations of H2O2 and aldehydes can be high. Formation of α-HHPs in ALW may significantly affect the effective Henry's law constants of H2O2 and aldehydes but may not affect their gas-phase levels. The photochemistry and reactivity of this class of atmospheric species have not been studied.

  15. The impact of varying atmospheric forcing on the thickness of arctic multi-year sea ice

    Science.gov (United States)

    Dumas, J. A.; Flato, G. M.; Weaver, A. J.

    2003-09-01

    A 1-D thermodynamic sea ice model, forced with North Pole Drift Station observations from 1954-91, is used to study the effect of changing atmospheric forcing on multi-year Arctic sea ice. From 1954-70, most seasons show positive trends in calculated sea ice thickness over much of the Arctic. A dip in calculated ice thickness takes place between 1971-77 over most of the Arctic. Following the North Pacific regime shift in 1976-1977, the period 1978-91 reveals large negative trends in calculated sea ice thickness in all seasons. The results indicate that an important part of the variability and trends in Arctic sea ice thickness is thermodynamically-driven. Of the total variance in multi-year sea ice thickness, 10 to 20% is explained by variations in the Arctic Oscillation and Pacific North American patterns. The multi-year ice thickness response to a positive wintertime Arctic Oscillation anomaly occurs the following summer and persists for more than a year.

  16. Formation of aqueous-phase α-hydroxyhydroperoxides (α-HHP): potential atmospheric impacts

    Science.gov (United States)

    Zhao, R.; Lee, A. K. Y.; Soong, R.; Simpson, A. J.; Abbatt, J. P. D.

    2013-06-01

    The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs) via reversible nucleophilic addition of H2O2 to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity. Specifically, the equilibrium constants of α-HHP formation have been determined using proton nuclear-magnetic-resonance (1H NMR) spectroscopy and proton-transfer-reaction mass spectrometry (PTR-MS). Significant α-HHP formation was observed from formaldehyde, acetaldehyde, propionaldehyde, glycolaldehyde, glyoxylic acid, and methylglyoxal, but not from methacrolein and ketones. Low temperatures enhanced the formation of α-HHPs but slowed their formation rates. High inorganic salt concentrations shifted the equilibria toward the hydrated form of the aldehydes and slightly suppressed α-HHP formation. Using the experimental equilibrium constants, we predict the equilibrium concentration of α-HHPs to be in the μM level in cloud water, but it may also be present in the mM level in aerosol liquid water (ALW), where the concentrations of H2O2 and aldehydes can be high. Formation of α-HHPs in ALW may significantly affect the effective Henry's law constants of H2O2 and aldehydes but may not affect their gas-phase levels. The photochemistry and reactivity of this class of atmospheric species have not been studied.

  17. The impact of Southwest Airline's contribution to atmospheric Carbon Dioxide and Nitrous Oxide totals

    Science.gov (United States)

    Wilkerson, Cody L.

    Over the last century, aviation has grown to become an economical juggernaut. The industry creates innovation, connects people, and maintains a safety goal unlike any other field. However, as the world becomes more populated with technology and individuals, a general curiosity as to how human activity effects the planet is becoming of greater interest. This study presents what one domestic airline in the United States, Southwest Airlines, contributes to the atmospheric make-up of the planet. Utilizing various sources of quantifiable data, an outcome was reached that shows the amount of Carbon Dioxide and Nitrous Oxide produced by Southwest Airlines from 2002 to 2013. This topic was chosen due to the fact that there are no real quantifiable values of emission statistics from airlines available to the public. Further investigation allowed for Southwest Airlines to be compared to the overall Carbon Dioxide and Nitrous Oxide contributions of the United States for the year 2011. The results showed that with the absence of any set standard on emissions, it is vital that one should be established. The data showed that the current ICAO standard emission values showed a higher level of emissions than when Southwest Airline's fleet was analyzed using their actual fleet mix.

  18. Impacts of Tibetan Plateau uplift on atmospheric dynamics and associated precipitation δ18O

    Science.gov (United States)

    Botsyun, Svetlana; Sepulchre, Pierre; Risi, Camille; Donnadieu, Yannick

    2016-06-01

    Palaeoelevation reconstructions of mountain belts have become a focus of modern science since surface elevation provides crucial information for understanding both geodynamic mechanisms of Earth's interior and the influence of mountain growth on climate. Stable oxygen isotopes palaeoaltimetry is one of the most popular techniques nowadays, and relies on the difference between δ18O of palaeo-precipitation reconstructed using the natural archives, and modern measured values for the point of interest. Our goal is to understand where and how complex climatic changes linked with the growth of mountains affect δ18O in precipitation. For this purpose, we develop a theoretical expression for the precipitation composition based on the Rayleigh distillation and the isotope-equipped atmospheric general circulation model LMDZ-iso outputs. Experiments with reduced height over the Tibetan Plateau and the Himalayas have been designed. Our results show that the isotopic composition of precipitation is very sensitive to climate changes related to the growth of the Himalayas and Tibetan Plateau. Specifically our simulations suggest that only 40 % of sampled sites for palaeoaltimetry depict a full topographic signal, and that uplift-related changes in relative humidity (northern region) and precipitation amount (southern region) could explain absolute deviations of up to 2.5 ‰ of the isotopic signal, thereby creating biases in palaeoelevation reconstructions.

  19. Model for the study of the impact of atmospheric heavy metals on soil microbial biomass

    Energy Technology Data Exchange (ETDEWEB)

    Marchionni, M.; Benedetti, A. [Istituto Sperimentale per la Nutrizione delle Piante, Rome (Italy); Riccardi, C.; Villarini, M. [Istituto Superiore per la Sicurezza e la Prevenzione del Lavoro, Rome (Italy)

    2000-12-01

    In the Castelporziano (Rome) protected area the inputs of atmospheric heavy metals on the soil-plant system were evaluated by the analysis of stem-flowing water from Quercus ilex L. The heavy metals detected in the soil under the canopies exhibited higher concentrations near to the tree trunks, highlighting the tree's capacity to concentrate such polluting substances. Microbial biomass, its specific respiration and the biomass calculated as a percentage of total soil organic matter, were utilised as indicators of the state of the soil and consequently also its quality with respect to heavy metal contamination. [Italian] Nell'area protetta di Castelporziano (Roma) e' stato valutato l'apporto dei metalli pesanti di origine atmosferica al sistema suolo-pianta analizzando le acque dilavanti di alberi d'alto fusto (Quercus ilex L.). I metalli pesanti rilevati nel suolo sottochioma presentano una piu' alta concentrazione in prossimita' del fusto, evidenziando la capacita' dell'albero di concentrare tali inquinanti. La biomassa microbica, la sua respirazione specifica e la biomassa espressa come percentuale della sostanza organica totale del suolo, sono state utilizzate quali indicatori dello stato del suolo, quindi della sua qualita', rispetto alla contaminazione da metalli pesanti.

  20. Atmospheric considerations regarding the impact of heat dissipation from a nuclear energy center

    International Nuclear Information System (INIS)

    Potential changes in climate resulting from a large nuclear energy center are discussed. On a global scale, no noticeable changes are likely, but on both a regional and a local scale, changes can be expected. Depending on the cooling system employed, the amount of fog may increase, the amount and distribution of precipitation will change, and the frequency or location of severe storms may change. Very large heat releases over small surface areas can result in greater atmospheric instability; a large number of closely spaced natural-draft cooling towers have this disadvantage. On the other hand, employment of natural-draft towers makes an increase in the occurrence of ground fog unlikely. The analysis suggests that the cooling towers for a large nuclear energy center should be located in clusters of four with at least 2.5-mile spacing between the clusters. This is equivalent to the requirement of one acre of land surface per each two megawatts of heat being rejected

  1. Remote impact of the Antarctic atmosphere on the southern mid-latitudes

    Directory of Open Access Journals (Sweden)

    Tido Semmler

    2016-02-01

    Full Text Available Would improved prediction capabilities over the Antarctic lead to improved forecast skill in southern mid-latitudes? Or more generally speaking, how large is the influence of the Antarctic atmosphere on the weather and climate of the southern mid-latitudes? To answer these questions we assess the skill of two sets of 14‑day forecasts with the Integrated Forecast System of the European Centre for Medium-Range Weather Forecasts with and without relaxation towards the Interim reanalysis of the ECMWF over the Antarctic south of 75 ° S. Due to the relaxation both the mean absolute error and the root mean square error decrease by 2 to 5 % averaged over the southern mid-latitudes with the larger values in winter. Over southern South America and the South Atlantic error reductions are slightly larger and amount to around 5 to 6 %. No dependency of the error reductions of the El Niño Southern Oscillation or the Antarctic Oscillation could be found although error reductions averaged over the whole southern mid-latitudes tend to be larger in situations with decreased westerly flow in the mid-latitudes. In weather situations with anomalous meridional flow from Antarctica to southern South America improvements are most pronounced in the latter area which implies that this is the major pathway for Antarctic influence on southern mid-latitude weather and climate.

  2. The climatological moisture sources and sinks for Atmospheric Rivers impacting the West Coast of the United States in modern and doubled CO2 climates.

    Science.gov (United States)

    Nusbaumer, J. M.; Noone, D. C.

    2015-12-01

    Atmospheric rivers are known to be major drivers of precipitation in many parts of the globe, including the West Coast of the United States. Atmospheric rivers are usually identified as long, filamentary structures of elevated vertically-integrated water vapor transport, and can extend over thousands of km, from the tropics all the way to the midlatitudes. However, it is generally unclear where exactly the moisture in atmospheric rivers comes from, and if that moisture is transported over long distances across the entire river, or if it is continuously precipitated out and replenished by local moisture. By better constraining the sources and sinks of moisture in atmospheric rivers, one can learn which geographic regions or meteorological processes are important for forecasting the rivers' hydrological impacts. Also, by determining how these moisture sources and sinks will change with the global climate, one can gain a better understanding of future atmospheric river conditions, and thus better future hydroclimate projections. We show the sources and sinks of water vapor and cloud condensate in atmospheric rivers as simulated by the water tracer-enabled NCAR Community Atmosphere Model Version 5 (CAM5). Specifically, numerous regions in the North Pacific and Western North America are tagged with water tracers, and their relative contributions to atmospheric river moisture and precipitation are calculated for rivers that impact the West Coast of the United States. Two simulations using the model are performed, one with modern-day boundary conditions, and another with doubled-CO2 conditions. It is found that the majority of moisture in atmospheric rivers comes from the subtropical (20 to 30° N) Pacific, although a substantial portion of moisture for some atmospheric rivers also comes from the tropics (river is from the source, indicating a continuous loss by precipitation, and a replacement by locally evaporated moisture. However, there can still be non

  3. Impacts of interruption of the Agulhas leakage on the tropical Atlantic in coupled ocean-atmosphere simulations

    Energy Technology Data Exchange (ETDEWEB)

    Haarsma, Reindert J.; Drijfhout, Sybren; Hazeleger, Wilco; Severijns, Camiel [Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt (Netherlands); Campos, Edmo J.D. [University of Sao Paulo (IOUSP), Oceanographic Institute, Sao Paulo (Brazil)

    2011-03-15

    In this paper we use a coupled ocean-atmosphere model to investigate the impact of the interruption of Agulhas leakage of Indian ocean water on the tropical Atlantic, a region where strong coupled ocean-atmosphere interactions occur. The effect of a shut down of leakage of Indian ocean water is isolated from the effect of a collapse of the MOC. In our experiments, the ocean model is forced with boundary conditions in the southeastern corner of the domain that correspond to no interocean exchange of Indian ocean water into the Atlantic. The southern boundary condition is taken from the Levitus data and ensures an MOC in the Atlantic. Within this configuration, instead of warm and salty Indian ocean water temperature (cold) and salinity (fresh) anomalies of southern ocean origin propagate into the South Atlantic and eventually reach the equatorial region, mainly in the thermocline. This set up mimics the closure of the ''warm water path'' in favor of the ''cold water path''. As part of the atmospheric response, there is a northward shift of the intertropical convergence zone (ITCZ). The changes in trade winds lead to reduced Ekman pumping in the equatorial region. This leads to a freshening and warming of the surface waters along the equator. Especially in the Cold Tongue region, the cold and fresh subsurface anomalies do not reach the surface due to the reduced upwelling. The anomaly signals are transported by the equatorial undercurrent and spread away from the equator within the thermocline. Part of the anomaly eventually reaches the Tropical North Atlantic, where it affects the Guinea Dome. Surprisingly, the main effect at the surface is small on the equator and relatively large at the Guinea Dome. In the atmosphere, the northward shift of the ITCZ is associated with a band of negative precipitation anomalies and higher salinities over the Tropical South Atlantic. An important implication of these results is that the

  4. Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

    International Nuclear Information System (INIS)

    The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken. (author)

  5. The impact of vibrational Raman scattering of air on DOAS measurements of atmospheric trace gases

    Science.gov (United States)

    Lampel, J.; Frieß, U.; Platt, U.

    2015-09-01

    In remote sensing applications, such as differential optical absorption spectroscopy (DOAS), atmospheric scattering processes need to be considered. After inelastic scattering on N2 and O2 molecules, the scattered photons occur as additional intensity at a different wavelength, effectively leading to "filling-in" of both solar Fraunhofer lines and absorptions of atmospheric constituents, if the inelastic scattering happens after the absorption. Measured spectra in passive DOAS applications are typically corrected for rotational Raman scattering (RRS), also called Ring effect, which represents the main contribution to inelastic scattering. Inelastic scattering can also occur in liquid water, and its influence on DOAS measurements has been observed over clear ocean water. In contrast to that, vibrational Raman scattering (VRS) of N2 and O2 has often been thought to be negligible, but it also contributes. Consequences of VRS are red-shifted Fraunhofer structures in scattered light spectra and filling-in of Fraunhofer lines, additional to RRS. At 393 nm, the spectral shift is 25 and 40 nm for VRS of O2 and N2, respectively. We describe how to calculate VRS correction spectra according to the Ring spectrum. We use the VRS correction spectra in the spectral range of 420-440 nm to determine the relative magnitude of the cross-sections of VRS of O2 and N2 and RRS of air. The effect of VRS is shown for the first time in spectral evaluations of Multi-Axis DOAS data from the SOPRAN M91 campaign and the MAD-CAT MAX-DOAS intercomparison campaign. The measurements yield in agreement with calculated scattering cross-sections that the observed VRS(N2) cross-section at 393 nm amounts to 2.3 ± 0.4 % of the cross-section of RRS at 433 nm under tropospheric conditions. The contribution of VRS(O2) is also found to be in agreement with calculated scattering cross-sections. It is concluded, that this phenomenon has to be included in the spectral evaluation of weak absorbers as it

  6. A Method for Detecting the Impact of Atmospheric Storms on Hydrothermal Systems

    Science.gov (United States)

    Bemis, K. G.; Ozer, S.; Xu, G.; Silver, D.; Rona, P. A.

    2013-12-01

    predictions and successful models of bending in response to normal tides will be compared with other measures of the Grotto vents to improve understanding of the normal variation in this system. Figure 1 shows a detected activity that may reflect internal waves generated by an atmospheric storm and propagated downward through the deep ocean. Ozer, S., Silver, D., Bemis, K., Martin, P., 2013, Activity detection for scientific visualization, Transactions in Visualization and Computer Graphics, submitted. Figure 1. Plume bending labeled with normal (blue stars) and unexpected (pink stars) bending modes for Oct. 21-24, 2010. Green and red lines mark when the plume bends consistently to the northeast and then to the southwest. This departure from the usual tidally-driven sloshing (gray dashed line) may indicate the overhead passage of an atmospheric storm.

  7. Impacts of Elevated Atmospheric CO2 and O3 on Paper Birch (Betula papyrifera: Reproductive Fitness

    Directory of Open Access Journals (Sweden)

    Joseph N. T. Darbah

    2007-01-01

    Full Text Available Atmospheric CO2 and tropospheric O3 are rising in many regions of the world. Little is known about how these two commonly co-occurring gases will affect reproductive fitness of important forest tree species. Here, we report on the long-term effects of CO3 and O3 for paper birch seedlings exposed for nearly their entire life history at the Aspen FACE (Free Air Carbon Dioxide Enrichment site in Rhinelander, WI. Elevated CO2 increased both male and female flower production, while elevated O3 increased female flower production compared to trees in control rings. Interestingly, very little flowering has yet occurred in combined treatment. Elevated CO2 had significant positive effect on birch catkin size, weight, and germination success rate (elevated CO2 increased germination rate of birch by 110% compared to ambient CO2 concentrations, decreased seedling mortality by 73%, increased seed weight by 17%, increased root length by 59%, and root-to-shoot ratio was significantly decreased, all at 3 weeks after germination, while the opposite was true of elevated O3 (elevated O3 decreased the germination rate of birch by 62%, decreased seed weight by 25%, and increased root length by 15%. Under elevated CO2, plant dry mass increased by 9 and 78% at the end of 3 and 14 weeks, respectively. Also, the root and shoot lengths, as well as the biomass of the seedlings, were increased for seeds produced under elevated CO2, while the reverse was true for seedlings from seeds produced under the elevated O3. Similar trends in treatment differences were observed in seed characteristics, germination, and seedling development for seeds collected in both 2004 and 2005. Our results suggest that elevated CO2 and O3 can dramatically affect flowering, seed production, and seed quality of paper birch, affecting reproductive fitness of this species.

  8. Atmospheric ammonia over China: emission estimates and impacts on air quality

    Science.gov (United States)

    Zhang, Lin; Zhao, Yuanhong; Chen, Youfan; Henze, Daven

    2016-04-01

    Ammonia (NH3) in the atmosphere is an important precursor of inorganic aerosols, and its deposition through wet and dry processes can cause adverse effects on ecosystems. The ammonia emissions over China are particularly large due to intensive agricultural activities, yet our current estimates of Chinese ammonia emissions and associated consequences on air quality are subject to large errors. Here we use the GEOS-Chem chemical transport model and its adjoint model to better quantify this issue. The TES satellite observations of ammonia concentrations and surface measurements of wet deposition fluxes are assimilated into the model to constrain the ammonia emissions over China. Optimized emissions show a strong seasonal variability with emissions in summer a factor of 3 higher than winter. We improve the bottom-up estimate of Chinese ammonia emissions from fertilizer use by using more practical feritilizer application rates for different crop types, which explains most of the discrepancies between our top-down estimates and prior emission estimates. We further use the GEOS-Chem adjoint at 0.25x0.3125 degree resolution to examine the sources contributing to the PM2.5 air pollution over North China. We show that wintertime PM2.5 over Beijing is largely contributed by residential and industrial sources, and ammonia emissions from agriculture activities. PM2.5 concentrations over North China are particularly sensitive to NH3 emissions in cold seasons due to strong nitrate formation. By converting shorted-lived nitric acid to aerosol nitrate, NH3 significantly promotes the regional transport influences of PM2.5 sources.

  9. The impacts of permafrost thaw on land-atmosphere greenhouse gas exchange

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Daniel J [ORNL; Kicklighter, David W. [Ecosystem Center, The; McGuire, A. David [University of Alaska; Chen, Min [Purdue University; Zhuang, Qianlai [Purdue University; Yuan, Fengming [ORNL; Melillo, Jerry [Marine Biological Laboratory; Wullschleger, Stan [ORNL

    2014-01-01

    Permafrost thaw and the subsequent mobilization of carbon stored in previously frozen soil organic matter (SOM) would be a strong positive feedback to climate1. As the northern permafrost region experiences double the rate of warming as the rest of the Earth2, the vast amount of carbon in permafrost soils3 is vulnerable to thaw, decomposition and release as atmospheric greenhouse gases (GHG). Here, we employ a process-based model simulation experiment to assess the net effect of this so-called permafrost carbon feedback (PCF) in recent decades. Results show a wide-spread increase in the depth to permafrost between 1990 and 2006, with simulated active layer thickness (ALT) capturing the mean and spatial variability of the observational data. Analysis of the simulation experiment provides an estimate of a 2.8 mm/yr increase in permafrost depth, which translates to 281 TgC/yr thawed from previously frozen SOM. Overall, we estimate a net GHG forcing of 534 MtCO2eq/yr directly tied to ALT dynamics, while accounting for CO2 (562 MtCO2eq/yr) and CH4 (52 MtCO2eq/yr) release as well as CO2 uptake by vegetation (-80 MtCO2eq/yr). This net forcing represents a significant factor in the estimated 640 MtCO2eq/yr pan-arctic GHG source4, and an additional 6.9% contribution on top of the combined 7792 MtCO2eq/yr fossil fuel emissions from the eight Arctic nations over this time period5.

  10. Assessment of atmospheric impacts of biomass open burning in Kalimantan, Borneo during 2004

    Science.gov (United States)

    Mahmud, Mastura

    2013-10-01

    Biomass burning from the combustion of agricultural wastes and forest materials is one of the major sources of air pollution. The objective of the study is to investigate the major contribution of the biomass open burning events in the island of Borneo, Indonesia to the degradation of air quality in equatorial Southeast Asia. A total of 10173 active fire counts were detected by the MODIS Aqua satellite during August 2004, and consequently, elevated the PM10 concentration levels at six air quality stations in the state of Sarawak, in east Malaysia, which is located in northwestern Borneo. The PM10 concentrations measured on a daily basis were above the 50 μg m-3 criteria as stipulated by the World Health Organization Air Quality Guidelines for most of the month, and exceeded the 24-h Recommended Malaysian Air Quality Guidelines of 150 μg m-3 on three separate periods from the 13th to the 30th August 2004. The average correlation between the ground level PM10 concentrations and the satellite derived aerosol optical depth (AOD) of 0.3 at several ground level air quality stations, implied the moderate relationship between the aerosols over the depth of the entire column of atmosphere and the ground level suspended particulate matter. Multiple regression for meteorological parameters such as rainfall, windspeed, visibility, mean temperature, relative humidity at two stations in Sarawak and active fire counts that were located near the centre of fire activities were only able to explain for 61% of the total variation in the AOD. The trajectory analysis of the low level mesoscale meteorological conditions simulated by the TAPM model illustrated the influence of the sea and land breezes within the lowest part of the planetary boundary layer, embedded within the prevailing monsoonal southwesterlies, in circulating the aged and new air particles within Sarawak.

  11. Impact of optimized mixing heights on simulated regional atmospheric transport of CO2

    Directory of Open Access Journals (Sweden)

    R. Kretschmer

    2014-02-01

    Full Text Available The mixing height (MH is a crucial parameter in commonly used transport models that proportionally affects air concentrations of trace gases with sources/sinks near the ground and on diurnal scales. Past synthetic data experiments indicated the possibility to improve tracer transport by minimizing errors of simulated MHs. In this paper we evaluate a method to constrain the Langrangian particle dispersion model STILT (Stochastic Time-Inverted Lagrangian Transport with MH diagnosed from radiosonde profiles using a bulk Richardson method. The same method was used to obtain hourly MHs for the period September/October 2009 from the Weather Research and Forecasting (WRF model, which covers the European continent at 10 km horizontal resolution. Kriging with External Drift (KED was applied to estimate optimized MHs from observed and modelled MHs, which were used as input for STILT to assess the impact on CO2 transport. Special care has been taken to account for uncertainty in MH retrieval in this estimation process. MHs and CO2 concentrations were compared to vertical profiles from aircraft in-situ data. We put an emphasis on testing the consistency of estimated MHs to observed vertical mixing of CO2. Modelled CO2 was also compared with continuous measurements made at Cabauw and Heidelberg stations. WRF MHs were significantly biased by ~10–20% during day and ~40–60% during night. Optimized MHs reduced this bias to ~5% with additional slight improvements in random errors. The KED MHs were generally more consistent with observed CO2 mixing. The use of optimized MHs had in general a favourable impact on CO2 transport, with bias reductions of 5–45% (day and 60–90% (night. This indicates that a large part of the found CO2 model-data mismatch was indeed due to MH errors. Other causes for CO2 mismatch are discussed. Applicability of our method is discussed in the context of CO2 inversions at regional scales.

  12. Impact of optimized mixing heights on simulated regional atmospheric transport of CO2

    Directory of Open Access Journals (Sweden)

    R. Kretschmer

    2014-07-01

    Full Text Available The mixing height (MH is a crucial parameter in commonly used transport models that proportionally affects air concentrations of trace gases with sources/sinks near the ground and on diurnal scales. Past synthetic data experiments indicated the possibility to improve tracer transport by minimizing errors of simulated MHs. In this paper we evaluate a method to constrain the Lagrangian particle dispersion model STILT (Stochastic Time-Inverted Lagrangian Transport with MH diagnosed from radiosonde profiles using a bulk Richardson method. The same method was used to obtain hourly MHs for the period September/October 2009 from the Weather Research and Forecasting (WRF model, which covers the European continent at 10 km horizontal resolution. Kriging with external drift (KED was applied to estimate optimized MHs from observed and modelled MHs, which were used as input for STILT to assess the impact on CO2 transport. Special care has been taken to account for uncertainty in MH retrieval in this estimation process. MHs and CO2 concentrations were compared to vertical profiles from aircraft in situ data. We put an emphasis on testing the consistency of estimated MHs to observed vertical mixing of CO2. Modelled CO2 was also compared with continuous measurements made at Cabauw and Heidelberg stations. WRF MHs were significantly biased by ~10–20% during day and ~40–60% during night. Optimized MHs reduced this bias to ~5% with additional slight improvements in random errors. The KED MHs were generally more consistent with observed CO2 mixing. The use of optimized MHs had in general a favourable impact on CO2 transport, with bias reductions of 5–45% (day and 60–90% (night. This indicates that a large part of the found CO2 model–data mismatch was indeed due to MH errors. Other causes for CO2 mismatch are discussed. Applicability of our method is discussed in the context of CO2 inversions at regional scales.

  13. A global model study of the impact of land-use change in Borneo on atmospheric composition

    Directory of Open Access Journals (Sweden)

    N. J. Warwick

    2013-09-01

    Full Text Available In this study, a high resolution version of the Cambridge p-TOMCAT chemical transport model is used, along with measurement data from the 2008 NERC-funded Oxidant and Particle Photochemical Processes (OP3 project, to examine the potential impact of the expansion of oil palm in Borneo on atmospheric composition. Several model emission scenarios are run for the OP3 measurement period, incorporating emissions from both global datasets and local flux measurements. Using the OP3 observed isoprene fluxes and OH recycling chemistry in p-TOMCAT substantially improves the comparison between modelled and observed isoprene and OH concentrations relative to using MEGAN isoprene emissions without OH recycling. However, a similar improvement was also achieved without using HOx recycling, by fixing boundary layer isoprene concentrations over Borneo to follow the OP3 observations. An extreme hypothetical future scenario, in which all of Borneo is converted to oil palm plantation, assessed the sensitivity of the model to changes in isoprene and NOx emissions associated with land-use change. This scenario suggested a 70% upper limit on surface ozone increases resulting from land-use change on Borneo, excluding the impact of future changes in emissions elsewhere. Although the largest changes in this scenario occurred directly over Borneo, the model also calculated notable regional changes of O3, OH and other species downwind of Borneo and in the free troposphere.

  14. Impact of resolving the diurnal cycle in an ocean-atmosphere GCM. Pt. 2. A diurnally coupled CGCM

    Energy Technology Data Exchange (ETDEWEB)

    Bernie, D.J. [Met Office Hadley Centre, Exeter (United Kingdom); University of Reading, National Centre for Atmospheric Science-Climate, Department of Meteorology, Reading (United Kingdom); Numeriques, IPSL, Laboratoire d' Oceanographie et du Climat, Experimentation et Approches, Paris (France); Guilyardi, E. [University of Reading, National Centre for Atmospheric Science-Climate, Department of Meteorology, Reading (United Kingdom); Numeriques, IPSL, Laboratoire d' Oceanographie et du Climat, Experimentation et Approches, Paris (France); Madec, G. [Numeriques, IPSL, Laboratoire d' Oceanographie et du Climat, Experimentation et Approches, Paris (France); Slingo, J.M.; Woolnough, S.J.; Cole, J. [University of Reading, National Centre for Atmospheric Science-Climate, Department of Meteorology, Reading (United Kingdom)

    2008-12-15

    the dynamical response of the ocean leads to a stronger equatorial upwelling. These two processes both lead to stronger seasonal basin scale feedbacks in the coupled system, increasing the strength of the seasonal cycle of the tropical Pacific sector by around 10%. This means that the diurnal cycle in the upper ocean plays a part in the coupled feedbacks between ocean and atmosphere that maintain the basic state and the timing of the seasonal cycle of SST and trade winds in the tropical Pacific. The Madden-Julian Oscillation (MJO) is examined by use of a large scale MJO index, lag correlations and composites of events. The inclusion of the diurnal cycle leads to a reduction in overall MJO activity. Precipitation composites show that the MJO is stronger and more coherent when the diurnal cycle of coupling is resolved, with the propagation and different phases being far more distinct both locally and to larger lead times across the tropical Indo-Pacific. Part one of this study showed that that diurnal variability of SST is modulated by the MJO and therefore increases the intraseasonal SST response to the different phases of the MJO. Precipitation-based composites of SST variability confirm this increase in the coupled simulations. It is argued that including this has increased the thermodynamical coupling of the ocean and atmosphere on the timescale of the MJO (20-100 days), accounting for the improvement in the MJO strength and coherency seen in composites of precipitation and SST. These results show that the diurnal cycle of ocean-atmosphere interaction has profound impact on a range of up-scale variability in the tropical climate and as such, it is an important feature of the modelled climate system which is currently either neglected or poorly resolved in state of the art coupled models. (orig.)

  15. Impacts of Different Water Pollution Sources on Antioxidant Defense Ability in Three Aquatic Macrophytes in Assiut Province, Egypt

    OpenAIRE

    Mohamed A.A. Gadallah; Suzan A. Sayed

    2014-01-01

    The present study was undertaken to evaluate the impacts of surface water pollution with wastes coming from sewage effluents (Site 2), agricultural runoff (Site 4) and oils and detergents factory (Site 3) on the stability of leaf membrane (measured as injury %), hydrogen peroxide (H 2O 2), ascorbic acid (Asc A), lipid peroxidation, chlorophyll (Chl) content, soluble sugars (SS), soluble proteins (SP) and total free amino acids (TAA) of Cyperus alopeucroides, Persicaria salicifolia and Echinoc...

  16. Augmentation of water-holding and textural properties of breast meat from oxidatively stressed broilers by dietary antioxidant regimens.

    Science.gov (United States)

    Delles, R M; Xiong, Y L; True, A D; Ao, T; Dawson, K A

    2015-01-01

    1. The impact of dietary antioxidants and degree of oil oxidation on textural attributes of chicken broiler breast meat stored in oxygen-enriched, air-permeable polyvinylchloride and skin packaging systems during retail display at 2-4°C for up to 21 d was assessed. 2. Broilers were fed on diets either with a low-oxidised oil (peroxide 23 mEq O2/kg) or with a high-oxidised oil (peroxide 121 mEq O2/kg), with or without an algae-based antioxidant and organic mineral antioxidant supplement for 42 d. 3. Fatty acids and radical scavenging activities of the diets were estimated. Meat colour, pH, myofibrillar protein profile and textural traits were measured. 4. Diets with high-oxidised oil reduced stearic, linoleic and linolenic acid content compared to low-oxidised oil samples, regardless of antioxidant supplementation. Meat colour and pH varied among dietary treatments throughout storage. Meat samples from the antioxidant dietary group, irrespective of oil oxidation level, had lower amounts of purge and cooking losses compared to the unsupplemented diets. For all packaging systems, meat shear force was significantly higher for broilers fed on high-oxidised diets. 5. The results demonstrate that dietary antioxidant supplementation can minimise the negative impact of oxidised oil on the quality of broiler meat packaged in different atmospheric environments. PMID:25854630

  17. Biomass burning influences on atmospheric composition: A case study to assess the impact of aerosol data assimilation

    Science.gov (United States)

    Keslake, Tim; Chipperfield, Martyn; Mann, Graham; Flemming, Johannes; Remy, Sam; Dhomse, Sandip; Morgan, Will

    2016-04-01

    The C-IFS (Composition Integrated Forecast System) developed under the MACC series of projects and to be continued under the Copernicus Atmospheric Monitoring System, provides global operational forecasts and re-analyses of atmospheric composition at high spatial resolution (T255, ~80km). Currently there are 2 aerosol schemes implemented within C-IFS, a mass-based scheme with externally mixed particle types and an aerosol microphysics scheme (GLOMAP-mode). The simpler mass-based scheme is the current operational system, also used in the existing system to assimilate satellite measurements of aerosol optical depth (AOD) for improved forecast capability. The microphysical GLOMAP scheme has now been implemented and evaluated in the latest C-IFS cycle alongside the mass-based scheme. The upgrade to the microphysical scheme provides for higher fidelity aerosol-radiation and aerosol-cloud interactions, accounting for global variations in size distribution and mixing state, and additional aerosol properties such as cloud condensation nuclei concentrations. The new scheme will also provide increased aerosol information when used as lateral boundary conditions for regional air quality models. Here we present a series of experiments highlighting the influence and accuracy of the two different aerosol schemes and the impact of MODIS AOD assimilation. In particular, we focus on the influence of biomass burning emissions on aerosol properties in the Amazon, comparing to ground-based and aircraft observations from the 2012 SAMBBA campaign. Biomass burning can affect regional air quality, human health, regional weather and the local energy budget. Tropical biomass burning generates particles primarily composed of particulate organic matter (POM) and black carbon (BC), the local ratio of these two different constituents often determining the properties and subsequent impacts of the aerosol particles. Therefore, the model's ability to capture the concentrations of these two

  18. Current and Future Impacts of Atmospheric Nitrogen Deposition on Grassland GHG Balance

    Science.gov (United States)

    Hudiburg, T. W.; Gomez-Casanovas, N.; Bernacchi, C.; DeLucia, E. H.

    2014-12-01

    Nitrogen deposition (Ndep), a consequence of human activities, affects the greenhouse gas (GHG; CO2, N2O and CH4) sink capacity of terrestrial ecosystems. Grasslands play an important role in determining the concentration of GHGs in the atmosphere. While they store greater than 10% of terrestrial net primary productivity and sustain up to 30% of the world's organic C in their soils, grasslands also may be responsible for significant CH4 and N2O emissions. Many fertilization experiments have examined the response of grasslands to N loads of 50 to 100 kg N ha-1 yr-1. However, few studies have been designed to examine ecosystem responses to low N loads (< 20 kg N ha-1 yr-1) which they are likely to experience in the future according to the new IPCC representative concentration pathway (RCP) scenarios. This is consistent with the notion that the N saturation threshold at which Net Ecosystem Productivity (NEP) levels off, or the dose-response relationships between N2O, N-trace gases, CH4, and Ndep in grasslands have not being well characterized. We combined data from grassland ecosystems in major climate zones and biogeochemical modeling (DayCent v. 4.5) to characterize the dose-response relationship between increased Ndep and GHG, and other N-trace gases fluxes and N leaching of these grasslands. We used the synthesized data to evaluate the modeling for above- and belowground NPP, N2O, CH4, and response to N fertilization and climate. We found that in most cases increased Ndep will continue to increase the non-CO2 GHG source strength of grasslands, whereas NEP will saturate at N levels ranging from 10 - 70 kg N ha-1 yr-1depending on the precipitation, fire regime, and/or species composition of the grassland. Given these thresholds, we modeled the potential net GHG sink capacity for the world's major grassland biomes using several of the IPCC RCP scenarios which include a range of climate and Ndep trajectories. Our results suggest that although global grassland C

  19. Health Impacts Estimation of Mineralogical and Chemical Characterization of Suspended Atmospheric Particles over the East Desert

    Directory of Open Access Journals (Sweden)

    U. A. Rahoma

    2010-01-01

    Full Text Available Problem statement: The small size fraction of aerosols, measured as PM10 and PM2.5, rather than the larger particles, is considered to be responsible for most of the health effects. Such particles have a relatively long residence time in the atmosphere and can therefore travel over long distances. Hence, a large portion of ambient concentrations of PM10 and in particular of particles with an aerodynamic diameter less than 2.5 µm (PM2.5, can be attributed to long range trans boundary air pollution or to other remote sources. The estimates of exposure and of health effects are based on a number of uncertain assumptions and data sets, as described in previous article. Approach: In industrialized Middle East countries, the daily deposition of PM10 particles in the lungs is roughly 250 µg day-1, which represents a small dose in terms of traditional toxicology studies. Studies of PM10 have considered this total material but have not asked how much its chemical or physical characteristics contribute to its total toxicity. Results: This article focuses on the description of the present knowledge on PM10 concentration fields and predominant sources contributing to PM10 from long range transport of pollution. PM10 is a complex mixture of many known and unknown components; therefore, a short introduction on the composition of PM10 is given. The studies denote to the African dust from mean PM10 levels background levels are still 5-10 mg m3 higher in the Eastern Basin (EMB when compared with those in the Western (WMB, mainly due to the higher anthropogenic and sea spray loads. Conclusion: As regards for the seasonal trends, these are largely driven by the occurrence of African dust events, resulting in a spring-early summer maximum over the EMB and a clear summer maximum in the WMB, although in this later region the recirculation of aged air masses play an important role. Furthermore, a marked seasonal trend is still evident when subtracting the African

  20. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 1: Land transport and shipping

    Directory of Open Access Journals (Sweden)

    M. Righi

    2014-09-01

    Full Text Available Using the EMAC global climate-chemistry model coupled to the aerosol module MADE, we simulate the impact of land transport and shipping emissions on global atmospheric aerosol and climate in 2030. Future emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare the resulting 2030 land-transport- and shipping-induced aerosol concentrations to the ones obtained for the year 2000 in a previous study with the same model configuration. The simulations suggest that black carbon and aerosol nitrate are the most relevant pollutants from land transport in 2000 and 2030, but their impacts are characterized by very strong regional variations during this time period. Europe and North America experience a decrease in the land-transport-induced particle pollution, although in these regions this sector remains the dominant source of surface-level pollution in 2030 under all RCPs. In Southeast Asia, on the other hand, a significant increase is simulated, but in this region the surface-level pollution is still controlled by other sources than land transport. Shipping-induced air pollution is mostly due to aerosol sulfate and nitrate, which show opposite trends towards 2030. Sulfate is strongly reduced as a consequence of sulfur reduction policies in ship-fuels in force since 2010, while nitrate tends to increase due to the excess of ammonia following the reduction in ammonium-sulfate. The aerosol-induced climate impact of both sectors is dominated by aerosol-cloud effects and is projected to decrease between 2000 and 2030, nevertheless still contributing a significant radiative forcing to the Earth's radiation budget.

  1. The impact of atmospheric data assimilation on wave simulations in the Red Sea

    KAUST Repository

    Langodan, Sabique

    2016-03-11

    Although wind and wave modeling is rather successful in the open ocean, modeling enclosed seas, particularly seas with small basins and complex orography, presents challenges. Here, we use data assimilation to improve wind and wave simulations in the Red Sea. We generated two sets of wind fields using a nested, high-resolution Weather Research and Forecasting model implemented with (VARFC) and without (CTL) assimilation of observations. Available conventional and satellite data were assimilated using the consecutive integration method with daily initializations over one year (2009). By evaluating the two wind products against in-situ data from synoptic stations, buoys, scatterometers, and altimeters, we found that seasonal patterns of wind and wave variability were well reproduced in both experiments. Statistical scores for simulated winds computed against QuikSCAT, buoy, and synoptic station observations suggest that data assimilation decreases the root-mean-square error to values between 1 and 2 m s-1 and reduces the scatter index by 30% compared to the CTL. Sensitivity clearly increased around mountain gaps, where the channeling effect is better described by VARFC winds. The impact of data assimilation is more pronounced in wave simulations, particularly during extreme winds and in the presence of mountain jets. © 2016 Elsevier Ltd. All rights reserved.

  2. THE IMPACT OF PRECEDING ATMOSPHERIC CIRCULATION AND SST VARIATION ON FLOOD SEASON RAINFALL IN YUNNAN

    Institute of Scientific and Technical Information of China (English)

    YAN Hua-sheng; LU Ya-bin; CHENG Jian-gang; DUAN He; YANG Su-yu

    2005-01-01

    Spatial and temporal distribution characteristics and scale range of two significant areas were obtained by analyzing the relationship among summer rainfall in Yunnan province, height field and SST field (40°S - 40°N, 30 °E - 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa for Jan. to May and correlation, and field wave structure. Remote key regions among summer rainfall in Yunnan province, height field and SST field (40°S - 40°N, 30°E - 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa were studied through further analyzing of the circulation system and its climate / weather significance. The result shows that the forecast has dependable physical basis when height and SST fields were viewed as predictors and physical models of impacts on rainy season precipitation in Yunnan are preliminarily concluded.

  3. Ground-based simulation of the Earth's upper atmosphere oxygen impact on polymer composites with nanosized fillers

    Science.gov (United States)

    Novikov, Lev; Chernik, Vladimir; Voronina, Ekaterina; Chechenin, Nikolay; Samokhina, Maria S.; Bondarenko, Gennady G.; Gaidar, Anna I.; Vorobyeva, Ekaterina A.; Petrov, Dmitrii V.; Chirskaya, Natalia P.

    The improvement of durability of polymer composites to the space environment impact is a very important task because these materials are considered currently as very promising type of materials for aerospace engineering. By embedding various nanosized fillers into a polymer matrix it is possible to obtain composites with required mechanical, thermal, electrical and optic properties. However, while developing such materials for operation in low Earth orbits (LEO), it is necessary to study thoroughly their durability to the impact of atomic oxygen (AO) of the Earth’s upper atmosphere, because AO is the main factor that causes erosion and damage of spacecraft surface materials in LEO. Ground-based simulation of AO impact on polymer composites was performed on a magnetoplasmadynamic accelerator developed at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University. Polymer composite samples which were prepared as films of 30-50 mum thickness with different amount (3-20 wt%) of various inorganic and organic nanofillers including nanoparticles of metal oxides and carbides as well as polyethoxysiloxanes and carbon nanotubes (CNTs), were exposed to hyperthermal AO flow, and mass losses of samples were estimated. Changes in the structure of composite surface and in material optical properties were studied. The experiments demonstrated that embedding nanosized fillers into a polymer matrix can significantly reduced mass losses, and the good dispersion of fillers improves AO durability in comparison with initial polymers [1]. The computer simulation within the developed 2D Monte-Carlo model demonstrated a good agreement with the experimental data [2]. Special attention was given to the study of AO impact on aligned multiwalled CNTs and CNT-based composites [3]. Some results of computer simulation of hyperthermal oxygen atom interaction with CNT and graphene as well as with polymers are presented to discuss elementary processes which occur in nanostructures

  4. Direct observation of aerosol particles in aged agricultural biomass burning plumes impacting urban atmospheres

    Directory of Open Access Journals (Sweden)

    W. Y. Li

    2010-04-01

    Full Text Available Emissions from agricultural biomass burning (ABB in northern China have a significant impact on the regional and the global climate. According to the Giovanni's Aerosol optical depth (AOD map, the monthly average AOD at 550 nm in northern China in 2007 shows a maximum value of 0.7 in June, suggesting that episodes of severe aerosol pollution occurred in this region. Aerosol particles were collected in urban Beijing during regional brown hazes from 12 to 30 June, 2007. Transmission electron microscopy with energy-dispersive X-ray spectrometry characterized the morphology, composition, and mixing state of aerosol particles. Potassium salts (K2SO4 and KNO3, ammonium sulfate, soot, and organic particles predominated in fine particles (diameter <1 μm collected from 12 to 20 June, 2007. In contrast, from 21 to 30 June, 2007, ammonium sulfate, soot, and organic particles were dominant. Potassium-dominant particles as a tracer of biomass burning, together with wildfire maps, show that intensive regional ABB in northern China from 10 to 20 June, 2007 contributed significantly to the regional haze. After long-range transport, ABB particles exhibited marked changes in their morphology, elemental composition, and mixing state. Heterogeneous reactions completely converted KCl particles from ABB into K2SO4 and KNO3. Soot particles were generally mixed with potassium salts, ammonium salts, and organic particles. In addition, the abundant aged organic particles and soluble salts emitted by ABB become more hygroscopic and increase their size during long-range transport, becoming in effect additional cloud condensation nuclei. The high AOD (average value at 2.2 during 12 to 20 June, 2007, in Beijing is partly explained by the hygroscopic growth of aged fine aerosol particles and by the strong absorption of internally mixed soot particles, both coming from regional ABB emissions.

  5. Atmospheric impact of the 1783–1784 Laki Eruption: Part II Climatic effect of sulphate aerosol

    Directory of Open Access Journals (Sweden)

    E.-J. Highwood

    2003-01-01

    Full Text Available The long 1783-1784 eruption of Laki in southern Iceland, was one of the first eruptions to have been linked to an observed climate anomaly, having been held responsible for cold temperatures over much of the Northern Hemisphere in the period 1783-1785. Results from the first climate model simulation of the impact of a similar eruption to that of 1783-1784 are presented. Using sulphate aerosol fields produced in a companion chemical transport model simulation by Stevenson et al. (2003, the radiative forcing and climate response due to the aerosol are calculated here using the Reading Intermediate General Circulation Model (IGCM. The peak Northern Hemisphere mean direct radiative forcing is -5.5 Wm-2 in August 1783. The radiative forcing dies away quickly as the emissions from the volcano decrease; however, a small forcing remains over the Mediterranean until March 1784. There is little forcing in the Southern Hemisphere. There is shown to be an uncertainty of at least 50% in the direct radiative forcing due to assumptions concerning relative humidity and the sophistication of the radiative transfer code used. The indirect effects of the Laki aerosol are potentially large but essentially unquantifiable at the present time. In the IGCM at least, the aerosol from the eruption produces a climate response that is spatially very variable. The Northern Hemisphere mean temperature anomaly averaged over the whole of the calendar year containing most of the eruption is -0.21 K, statistically significant at the 95% level and in reasonable agreement with the available observations of the temperature during 1783.

  6. Characterization of vehicle emissions in São Paulo and the impacts on atmospheric chemistry and secondary aerosol formation

    Science.gov (United States)

    Ferreira De Brito, J.; Godoy, M.; Godoy, J.; Varanda Rizzo, L.; Artaxo, P.

    2012-12-01

    Megacities emissions are increasingly becoming a global issue, where emissions from the transportation sector play an important role. São Paulo, located in Southeast of Brazil, is a megacity with a population of 18 million people, 7 million cars and large-scale industrial emissions. As a result of the vehicular and industrial emissions, the air quality in São Paulo is considered one of the worst worldwide. Despite the large impact on human health and atmospheric chemistry/dynamics, many uncertainties are found on gas- and particulate matter vehicular emission factors and their following atmospheric processes, e.g. secondary organic aerosol formation. Due to the uniqueness of the vehicular fuel in Brazil, largely based on ethanol use, such characterization currently holds further uncertainties. To improve the understanding of the role of this unique emission pattern, we are running a source apportionment study in São Paulo. One of the goals of this study is a quantitative aerosol source apportionment focused on vehicular emissions, including ethanol and gasohol (both fuels used by light-duty vehicles) and diesel (heavy-duty vehicles). Whereas the latter shows usually much higher emission factors compared with ethanol or gasohol, heavy-duty vehicles have increasingly limited access within the São Paulo city limits, thus increasing the importance of light duty vehicles on air quality degradation. This study comprises four sampling sites, where trace elements and organic aerosol are being measured for PM2.5 and PM10 along with real-time NOx, ozone, PM10 and CO measurements. Aerosol optical properties and size distribution are being measured on a rotation basis between sampling stations. Furthermore, a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) and an Aerosol Chemical Speciation Monitor (ACSM) are used to real-time VOC analysis and aerosol composition, respectively. Results show aerosol number concentrations ranging between 10^4 and 3.10^4 cm-3, mostly

  7. CFCl3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime Uncertainty

    Science.gov (United States)

    McGillen, M.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

    2013-12-01

    CFCl3 (CFC-11) is both a major ozone-depleting substance and a potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95-230 nm) and temperature (216-296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using the NASA Goddard Space Flight Center 2-D coupled chemistry-radiation-dynamics model and the spectrum parameterization developed in this work. The modeled global annually averaged lifetime was 58.1 × 0.7 years (2σ uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current UV spectrum recommendations. CFCl 3 (CFC-11) 2-D model results: Left: Global annually averaged loss rate coefficient (local lifetime) and photolysis and reaction contributions (see legend). Middle: Molecular loss rate and uncertainty limits; the slow and fast profiles were calculated using the 2σ uncertainty estimates in the CFC-11 UV absorption spectrum from this work. Right: CFC-11 concentration profile. CFC-11 loss process contribution to the overall local lifetime uncertainty (2σ) calculated using the 2-D model (see text). Left: Results obtained from this work. Right: Results obtained using model input from Sander et al. [2011] and updates in SPARC [2013].

  8. Impacts of aerosols on the chemistry of atmospheric trace gases: a case study of peroxides and HO2 radicals

    Directory of Open Access Journals (Sweden)

    H. Liang

    2013-06-01

    Full Text Available Field measurements of atmospheric peroxides were obtained during the summer on two consecutive years over urban Beijing, and focused on the impacts of aerosols on the chemistry of peroxide compounds and hydroperoxyl radicals (HO2. The major peroxides were determined to be hydrogen peroxide (H2O2, methyl hydroperoxide (MHP, and peroxyacetic acid (PAA. A negative correlation was found between H2O2 and PAA in rainwater, providing evidence for a conversion between H2O2 and PAA in the aqueous phase. A standard gas phase chemistry model based on the NCAR Master Mechanism provided a good reproduction of the observed H2O2 profile on non-haze days but greatly overpredicted the H2O2 level on haze days. We attribute this overprediction to the reactive uptake of HO2 by the aerosols, since there was greatly enhanced aerosol loading and aerosol liquid water content on haze days. The discrepancy between the observed and modeled H2O2 can be diminished by adding to the model a newly proposed transition metal ion catalytic mechanism of HO2 in aqueous aerosols. This confirms the importance of the aerosol uptake of HO2 and the subsequent aqueous phase reactions in the reduction of H2O2. The closure of HO2 and H2O2 between the gas and aerosol phases suggests that the aerosols do not have a net reactive uptake of H2O2, because the conversion of HO2 to H2O2 on aerosols compensates for the H2O2 loss. Laboratory studies for the aerosol uptake of H2O2 in the presence of HO2 are urgently required to better understand the aerosol uptake of H2O2 in the real atmosphere.

  9. What's Up in the Atmosphere? Exploring How Aerosols Impact Sky Color Through Hands-on Activities with Elementary GLOBE

    Science.gov (United States)

    Damadeo, K.; Taylor, J.

    2015-12-01

    What color is the sky today? The GLOBE Kids - Anita, Simon, and Dennis want to know why the sky isn't always the same shade of blue and sometimes isn't even blue. Through the new Elementary GLOBE Aerosols Storybook and Learning Activities, the GLOBE Kids learn that there's a lot more than air in the atmosphere, which can affect the colors we see in the sky. There are four hands-on activities in this unit: 1) Sky Observers - Students make observations of the sky, record their findings and share their observation reports with their peers. The activity promotes active observation and recording skills to help students observe sky color, and recognize that sky color changes; 2) Why (Not) So Blue? - Students make predictions about how drops of milk will affect color and visibility in cups of water representing the atmosphere to help them understand that aerosols in the atmosphere have an effect on sky conditions, including sky color and visibility. The activity also introduces the classification categories for daytime sky color and visibility; 3) See the Light - Students use prisms and glue sticks to explore the properties of light. The activity demonstrates that white light is made up of seven colors that represent different wavelengths, and illustrates why the sky is blue during the day and red at sunset; 4) Up in the Air - Students work in groups to make an aerosol sampler, a simple adhesive tool that allows students to collect data and estimate the extent of aerosols present at their school, understanding that, in fact, there are particles in the air we breathe. NGSS Alignment includes: Disciplinary Core Ideas- ESS2.D: Weather and Climate, ESS3.C: Human Impacts on Earth Systems, PS4.B: Electromagnetic Radiation, ESS3.A: Natural Resources; Science and Engineering Practices- Asking Questions and Defining Problems, Planning and Carrying Out an Investigation, Analyzing and Interpreting Data, Engaging in Argument from Evidence, Obtaining, Evaluating, and Communicating

  10. Atmospheric isoprene ozonolysis: impacts of stabilized Criegee intermediate reactions with SO2, H2O and dimethyl sulfide

    Directory of Open Access Journals (Sweden)

    M. J. Newland

    2015-03-01

    , of 4.1 (±2.2. This result suggests that SCIs may contribute to the oxidation of DMS in the atmosphere and that this process could therefore influence new particle formation in regions impacted by emissions of unsaturated hydrocarbons and DMS.

  11. Atmospheric H2S and SO2 as sulfur source for Brassica juncea and Brassica rapa: Impact on the glucosinolate composition

    NARCIS (Netherlands)

    Aghajanzadeh, T.; Kopriva, S; Hawkesford, M.J.; Koprivova, A.; De Kok, L.J.

    2015-01-01

    The impact of sulfate deprivation and atmospheric H2S and SO2 nutrition on the content and composition of glucosinolates was studied in Brassica juncea and Brasscia rapa. Both species contained a number of aliphatic and indolic glucosinolates. The total glucosinolate content was more than 5.5-fold h

  12. Impact of predicted changes in rainfall and atmospheric carbon dioxide on maize and wheat yeilds in the Central Rift Valley of Ethiopia

    NARCIS (Netherlands)

    Muluneh, A.; Biazin, B.; Stroosnijder, L.; Bewket, W.; Keesstra, S.D.

    2015-01-01

    This study assesses potential impacts of climate change on maize and wheat yields in the Central Rift Valley (CRV) of Ethiopia. We considered effects of elevated atmospheric carbon dioxide (CO2) and changes in rainfall during the main (Kiremt) and the short (Belg) rainfall cropping seasons during th

  13. Modeling the impact of vapor thymol concentration, temperature and modified atmosphere condition on growth behavior of Salmonella spp. on raw shrimp

    Science.gov (United States)

    Salmonella spp. is a microorganism of concern, on a global basis, for raw shrimp. This research modeled the impact of vapor thymol concentration (0, 0.8 and 1.6 mg/l), storage temperature (8, 12 and 16 degree C) and modified atmosphere packaging (0.04 and 59.5 percent CO2) against the growth behavio...

  14. Future Climate CO2 Levels Mitigate Stress Impact on Plants: Increased Defense or Decreased Challenge?

    Science.gov (United States)

    AbdElgawad, Hamada; Zinta, Gaurav; Beemster, Gerrit T S; Janssens, Ivan A; Asard, Han

    2016-01-01

    Elevated atmospheric CO2 can stimulate plant growth by providing additional C (fertilization effect), and is observed to mitigate abiotic stress impact. Although, the mechanisms underlying the stress mitigating effect are not yet clear, increased antioxidant defenses, have been held primarily responsible (antioxidant hypothesis). A systematic literature analysis, including "all" papers [Web of Science (WoS)-cited], addressing elevated CO2 effects on abiotic stress responses and antioxidants (105 papers), confirms the frequent occurrence of the stress mitigation effect. However, it also demonstrates that, in stress conditions, elevated CO2 is reported to increase antioxidants, only in about 22% of the observations (e.g., for polyphenols, peroxidases, superoxide dismutase, monodehydroascorbate reductase). In most observations, under stress and elevated CO2 the levels of key antioxidants and antioxidant enzymes are reported to remain unchanged (50%, e.g., ascorbate peroxidase, catalase, ascorbate), or even decreased (28%, e.g., glutathione peroxidase). Moreover, increases in antioxidants are not specific for a species group, growth facility, or stress type. It seems therefore unlikely that increased antioxidant defense is the major mechanism underlying CO2-mediated stress impact mitigation. Alternative processes, probably decreasing the oxidative challenge by reducing ROS production (e.g., photorespiration), are therefore likely to play important roles in elevated CO2 (relaxation hypothesis). Such parameters are however rarely investigated in connection with abiotic stress relief. Understanding the effect of elevated CO2 on plant growth and stress responses is imperative to understand the impact of climate changes on plant productivity. PMID:27200030

  15. Future Climate CO2 Levels Mitigate Stress Impact on Plants: Increased Defense or Decreased Challenge?

    Science.gov (United States)

    AbdElgawad, Hamada; Zinta, Gaurav; Beemster, Gerrit T S; Janssens, Ivan A; Asard, Han

    2016-01-01

    Elevated atmospheric CO2 can stimulate plant growth by providing additional C (fertilization effect), and is observed to mitigate abiotic stress impact. Although, the mechanisms underlying the stress mitigating effect are not yet clear, increased antioxidant defenses, have been held primarily responsible (antioxidant hypothesis). A systematic literature analysis, including "all" papers [Web of Science (WoS)-cited], addressing elevated CO2 effects on abiotic stress responses and antioxidants (105 papers), confirms the frequent occurrence of the stress mitigation effect. However, it also demonstrates that, in stress conditions, elevated CO2 is reported to increase antioxidants, only in about 22% of the observations (e.g., for polyphenols, peroxidases, superoxide dismutase, monodehydroascorbate reductase). In most observations, under stress and elevated CO2 the levels of key antioxidants and antioxidant enzymes are reported to remain unchanged (50%, e.g., ascorbate peroxidase, catalase, ascorbate), or even decreased (28%, e.g., glutathione peroxidase). Moreover, increases in antioxidants are not specific for a species group, growth facility, or stress type. It seems therefore unlikely that increased antioxidant defense is the major mechanism underlying CO2-mediated stress impact mitigation. Alternative processes, probably decreasing the oxidative challenge by reducing ROS production (e.g., photorespiration), are therefore likely to play important roles in elevated CO2 (relaxation hypothesis). Such parameters are however rarely investigated in connection with abiotic stress relief. Understanding the effect of elevated CO2 on plant growth and stress responses is imperative to understand the impact of climate changes on plant productivity.

  16. Antioxidative defense

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka

    2011-01-01

    Full Text Available Free radicals occur constantly during metabolism and take part in numerous physiological processes, such as: intra-cellular and inter-cellular signalization, gene expression, removal of damaged or senescent cells, and control of the tone of blood vessels. However, there is an increased quantity of free radicals in situations of so-called oxidative stress, when they cause serious damage to cellular membranes (peroxidation of their lipids, damage of membrane proteins, and similar, to interior cellular protein molecules, as well as DNA molecules and carbohydrates. This is precisely why the organism has developed numerous mechanisms for removing free radicals and/or preventing their production. Some of these are enzyme-related and include superoxide-dismutase, catalase, glutathione-peroxidase, and others. Other, non-enzyme mechanisms, imply antioxidative activities of vitamins E and C, provitamin A, coenzyme Q, reduced glutation, and others. Since free radicals can leave the cell that has produced them and become dispersed throughout the body, in addition to antioxidative defense that functions within cellular structures, antioxidant extra-cellular defense has also been developed. This is comprised by: transferrin, lactoferrin, haptoglobin, hemopexin, ceruloplasmin, albumins, extra-cellular isoform SOD, extracellular glutathione-peroxidase, glucose, bilirubin, urates, and many other molecules.

  17. Impacts of Different Water Pollution Sources on Antioxidant Defense Ability in Three Aquatic Macrophytes in Assiut Province, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed A.A. Gadallah

    2014-08-01

    Full Text Available The present study was undertaken to evaluate the impacts of surface water pollution with wastes coming from sewage effluents (Site 2, agricultural runoff (Site 4 and oils and detergents factory (Site 3 on the stability of leaf membrane (measured as injury %, hydrogen peroxide (H2O2, ascorbic acid (Asc A, lipid peroxidation, chlorophyll (Chl content, soluble sugars (SS, soluble proteins (SP and total free amino acids (TAA of Cyperus alopeucroides, Persicaria salicifolia and Echinochloa stagnina. Concentration of H2O2, MDA and TAA were higher in the three plants collected from polluted sites as compared with those of plants grown in control Nile site (Site1. The opposite was true for Asc A, SS and SP where their concentrations reduced significantly in response to water pollution. Leaf membrane was more damaged (high injury % in plants exposed to wastes from different sources than in plants growing at control site. The results of this study indicated that water pollution reduced the oxidative defense abilities in the three plants through reduction of Asc A activities, enhancement of H2O2 production and increasing MDA accumulation. In addition it impaired the metabolic activity through lowering the SS and SP contents and enhancement of TAA accumulation and increase membrane injury. The over production of hydrogen peroxide by the studied aquatic plants under water pollution could be used as an oxygen source needed to oxidize the more resistant organic and inorganic pollutants and used for pollution control and municipal and industrial wastewater treatment.

  18. Resuspension and atmospheric transport of radionuclides due to wildfires near the Chernobyl Nuclear Power Plant in 2015: An impact assessment

    Science.gov (United States)

    Evangeliou, N.; Zibtsev, S.; Myroniuk, V.; Zhurba, M.; Hamburger, T.; Stohl, A.; Balkanski, Y.; Paugam, R.; Mousseau, T. A.; Møller, A. P.; Kireev, S. I.

    2016-05-01

    In April and August 2015, two major fires in the Chernobyl Exclusion Zone (CEZ) caused concerns about the secondary radioactive contamination that might have spread over Europe. The present paper assessed, for the first time, the impact of these fires over Europe. About 10.9 TBq of 137Cs, 1.5 TBq of 90Sr, 7.8 GBq of 238Pu, 6.3 GBq of 239Pu, 9.4 GBq of 240Pu and 29.7 GBq of 241Am were released from both fire events corresponding to a serious event. The more labile elements escaped easier from the CEZ, whereas the larger refractory particles were removed more efficiently from the atmosphere mainly affecting the CEZ and its vicinity. During the spring 2015 fires, about 93% of the labile and 97% of the refractory particles ended in Eastern European countries. Similarly, during the summer 2015 fires, about 75% of the labile and 59% of the refractory radionuclides were exported from the CEZ with the majority depositing in Belarus and Russia. Effective doses were above 1 mSv y‑1 in the CEZ, but much lower in the rest of Europe contributing an additional dose to the Eastern European population, which is far below a dose from a medical X-ray.

  19. Impacts of teachers’ competency on job performance in research universities with industry characteristics: Taking academic atmosphere as moderator

    Directory of Open Access Journals (Sweden)

    Anguo Xu

    2014-10-01

    Full Text Available Purpose: Research universities with industry characteristics play an irreplaceable role in national economic development and social development. With the rapid development of research universities with industry characteristics in China, these universities face new challenges in managing teachers and promoting their quality. This paper aims to examine the impact of teachers’ competency on job performance in research university with industry characteristics Design/methodology/approach: Based on the behavioral event interview and questionnaire methods, a four-dimension (i.e. basic quality, teaching ability, industry awareness and research capacity competency model was proposed, the influence mechanism of competency on job performance was examined using empirical research. Findings: We found that there is a significant positive correlation between the teachers’ competency level, four dimensions and job performance in research universities with industry characteristics, especially between research capacity, teaching ability, industry awareness and job performance. And academic atmosphere plays a regulatory role in the interaction between the competency and job performance. Practical implications: Our findings can help to improve the management level of teachers in research universities with industry characteristics.Originality/value: The paper introduces the competency theory to the teacher management in research universities with industry characteristics, and gives some interesting findings.

  20. Photodissociation in the atmosphere of Mars - Impact of high resolution, temperature-dependent CO2 cross-section measurements

    Science.gov (United States)

    Anbar, A. D.; Allen, M.; Nair, H. A.

    1993-01-01

    We have investigated the impact of high resolution, temperature-dependent CO2 cross-section measurements, reported by Lewis and Carver (1983), on calculations of photodissociation rate coefficients in the Martian atmosphere. We find that the adoption of 50 A intervals for the purpose of computational efficiency results in errors in the calculated values for photodissociation of CO2, H2O, and O2 which are generally not above 10 percent, but as large as 20 percent in some instances. These are acceptably small errors, especially considering the uncertainties introduced by the large temperature dependence of the CO2 cross section. The inclusion of temperature-dependent CO2 cross sections is shown to lead to a decrease in the diurnally averaged rate of CO2 photodissociation as large as 33 percent at some altitudes, and increases of as much as 950 percent and 80 percent in the photodissociation rate coefficients of H2O and O2, respectively. The actual magnitude of the changes depends on the assumptions used to model the CO2 absorption spectrum at temperatures lower than the available measurements, and at wavelengths longward of 1970 A.

  1. Impact of Peer Pressure and Store Atmosphere on Purchase Intention: An Empirical Study on the Youngsters in Pakistan

    Directory of Open Access Journals (Sweden)

    Fatima Gillani

    2012-07-01

    Full Text Available In any business the most important asset for the success is the “consumer”, they are the factors of sale and profits of the business. Knowing and understanding the customer is one of the most important, tedious and challenging aspect for any organization. This particular study aims to understand the buying behaviour of Pakistani consumers, and identify the factors which are of importance in determining the purchase intention of these consumers. The study has been conducted on a sample of 393 young students belonging to different colleges and universities of Pakistan. The study has targeted the young chunk of consumers in Pakistan as they make up a major and substantial part of the customer base for different organizations. The research has investigated the impact of two factors i.e. peer pressure and store atmosphere on the purchase intentions of these youngsters and concluded that there is a significant and positive relationship between the two factors and purchase intention. This empirical study is a contribution to theory and practice with an increased and detailed understanding on young Pakistani consumer behaviour and the underlying causes which are strong determinants of their purchase intentions.

  2. Natural antioxidants in meat and poultry products.

    Science.gov (United States)

    Karre, Liz; Lopez, Keyla; Getty, Kelly J K

    2013-06-01

    In response to recent claims that synthetic antioxidants have the potential to cause toxicological effects and consumers' increased interest in purchasing natural products, the meat and poultry industry has been seeking sources of natural antioxidants. Due to their high phenolic compound content, fruits and other plant materials provide a good alternative to conventional antioxidants. Plum, grape seed extract, cranberry, pomegranate, bearberry, pine bark extract, rosemary, oregano, and other spices functions as antioxidants in meat and poultry products. Pomegranate, pine bark extract, cinnamon, and cloves have exhibited stronger antioxidant properties than some synthetic options. Plum products, grape seed extract, pine bark extract, rosemary, and some spices all have been shown to affect the color of finished meat or poultry products; however, in some products such as pork sausage or uncured meats, an increase in red color may be desired. When selecting a natural antioxidant, sensory and quality impact on the product should be considered to achieve desired traits. PMID:23501254

  3. Impact of elevated CO2 and elevated O3 on Beta vulgaris L.: Pigments, metabolites, antioxidants, growth and yield

    International Nuclear Information System (INIS)

    The present study was conducted to assess morphological, biochemical and yield responses of palak (Beta vulgaris L. cv Allgreen) to ambient and elevated levels of CO2 and O3, alone and in combination. As compared to the plants grown in charcoal filtered air (ACO2), growth and yield of the plants increased under elevated CO2 (ECO2) and decreased under combination of ECO2 with elevated O3 (ECO2 + EO3), ambient O3 (ACO2 + AO3) and elevated O3 (EO3). Lipid peroxidation, ascorbic acid, catalase and glutathione reductase activities enhanced under all treatments and were highest in EO3. Foliar starch and organic carbon contents increased under ECO2 and ECO2 + EO3 and reduced under EO3 and ACO2 + AO3. Foliar N content declined in all treatments compared to ACO2 resulting in alteration of C/N ratio. This study concludes that ambient level of CO2 is not enough to counteract O3 impact, but elevated CO2 has potential to counteract the negative effects of future O3 level. -- Highlights: ► Elevated CO2 enhanced the growth and yield of palak. ► Ambient and elevated ozone reduced the growth and yield of the test plant. ► Elevated CO2 reduced negative effects of elevated O3 by reducing oxidative stress. ► Higher amelioration was recorded at elevated CO2 + O3 compared to ambient CO2 + O3. -- Predicted levels of CO2 have greater ameliorative potential against negative effects of elevated ozone compared to present day CO2 against ambient ozone

  4. Impact of a realistic river routing in coupled ocean-atmosphere simulations of the Last Glacial Maximum climate

    Energy Technology Data Exchange (ETDEWEB)

    Alkama, Ramdane [IPSL, Laboratoire des Sciences du Climat et de l' Environnement, Gif-sur-Yvette Cedex (France); Universite Pierre et Marie Curie, Structure et fonctionnement des systemes hydriques continentaux (Sisyphe), Paris (France); Kageyama, M.; Ramstein, G.; Marti, O.; Swingedouw, D. [IPSL, Laboratoire des Sciences du Climat et de l' Environnement, Gif-sur-Yvette Cedex (France); Ribstein, P. [Universite Pierre et Marie Curie, Structure et fonctionnement des systemes hydriques continentaux (Sisyphe), Paris (France)

    2008-06-15

    The presence of large ice sheets over North America and North Europe at the Last Glacial Maximum (LGM) strongly impacted Northern hemisphere river pathways. Despite the fact that such changes may significantly alter the freshwater input to the ocean, modified surface hydrology has never been accounted for in coupled ocean-atmosphere general circulation model simulations of the LGM climate. To reconstruct the LGM river routing, we use the ICE-5G LGM topography. Because of the uncertainties in the extent of the Fennoscandian ice sheet in the Eastern part of the Kara Sea, we consider two more realistic river routing scenarios. The first scenario is characterised by the presence of an ice dammed lake south of the Fennoscandian ice sheet, and corresponds to the ICE-5G topography. This lake is fed by the Ob and Yenisei rivers. In the second scenario, both these rivers flow directly into the Arctic Ocean, which is more consistent with the latest QUEEN ice sheet margin reconstructions. We study the impact of these changes on the LGM climate as simulated by the IPSL{sub C}M4 model and focus on the overturning thermohaline circulation. A comparison with a classical LGM simulation performed using the same model and modern river basins as designed in the PMIP2 exercise leads to the following conclusions: (1) The discharge into the North Atlantic Ocean is increased by 2,000 m{sup 3}/s between 38 and 54 N in both simulations that contain LGM river routing, compared to the classical LGM experiment. (2) The ice dammed lake is shown to have a weak impact, relative to the classical simulation, both in terms of climate and ocean circulation. (3) In contrast, the North Atlantic deep convection and meridional overturning are weaker than during the classical LGM run if the Ob and Yenisei rivers flow directly into the Arctic Ocean. The total discharge into the Arctic Ocean is increased by 31,000 m{sup 3}/s, relative to the classical LGM simulation. Consequentially, northward ocean heat

  5. Inversion of the Chelyabinsk seismic surface waves and comparative constraints on the generation of seismic waves by atmospheric Impacts on Earth and Mars

    Science.gov (United States)

    Karakostas, F. G.; Rakoto, V.; Lognonne, P. H.

    2015-12-01

    Meteor impacts are a very important seismic source for planetary seismology, since their locations and, in some cases, their occurence times can be accurately known from orbiters, tracking or optical observations. Their importance becomes greater in the case of a seismic experiment with one seismometer, as the SEIS (Seismic Experiment of Interior Structure) of the future Martian mission "InSight", as the known location allows a direct inversion of differential travel times and wave forms in terms of structure. Meteor impacts generate body and surface seismic waves when they reach the surface of a planet. But when they explode into the atmosphere, due to ablation, they generate shock waves, which are converted into linear, seismic waves in the solid part and acoustic waves in the atmosphere. This effect can be modeled when the amplitude of Rayleigh and other Spheroidal normal modes is made with the atmospheric/ground coupling effects. In this study, meteor impacts are modeled as seismic sources in a comparative analysis for the cases of Earth and Mars. Using the computed seismograms, calculated by the summation of the normal modes of the full planet (e.g. with atmosphere) the properties of the seismic source can be obtained. Its duration is typically associated to the radiation duration of shock waves until they reach the linear regime of propagation. These transition times are comparatively analyzed, for providing constraints on the seismic source duration on Earth and Mars. In the case of Earth, we test our approach with the Chelyabinsk superbolide. The computed seismograms are used in order to perform the inversion of the source, by comparison with the data of the Global Seismographic Network. The results are interpreted and compared with other observations. In the case of Mars, equivalent sources are similarly modeled in different atmospheric, impact size and lithospheric conditions.

  6. The impact of the Arctic Sea Ice retreat on extratropical cyclones and anticyclones over Northern Eurasia: atmospheric model simulations

    Science.gov (United States)

    Akperov, Mirseid; Semenov, Vladimir; Mokhov, Igor; Lupo, Antony

    2015-04-01

    The Arctic region has been warming more than twice as fast as the other parts of the world during the last few decades. The rapid Arctic warming is accompanied with the dramatic change of Arctic sea ice cover. Recently, it has been suggested that such climatic changes might have led to the increase of anomalous weather events in winter over Northern Eurasia. One example is anomalous cold winters over Northern Eurasia associated with atmospheric blocking events. However, a large uncertainty remains concerning robustness of the observed relationship and associated mechanisms of impact. The main goal of this research is to explore the connection between the declining Arctic sea ice (most strongly expressed in the Barents-Kara Seas region) in the cold season and the change of cyclonic and anti-cyclonic activity over Northern Eurasia using simulations with atmospheric general circulation model (AGCM). The simulations were performed with the ECHAM5 AGCM using identical sea surface temperature climatology but different sea ice concentrations (SIC) for the periods corresponding to the high (1966-1969), low (1990-1995) and very low (2005-2012) SIC regimes in the Arctic as well as for the mean climatological SIC for 1971-2000. The duration of each simulation was 50 years. For the regimes with high and very low SIC, a statistically significant increase in the number of long-living anticyclones (with lifetime of more than 5 days) over Northern Eurasia was found. Long-living cyclones exhibited different changes in their number depending on their intensity. The analysis of the spatial patterns of cyclonic and anti-cyclonic activity over Eurasia was performed. We found an increase of the frequency of cyclones over the central region of the European part of Russia (EPR) and anticyclones over the northern region of the EPR for the regimes with a high sea ice concentration in the Arctic. For the regime with very low SIC the shift of the frequency of cyclones and anticyclones towards

  7. The impact of climate and composition on playa surface roughness: Investigation of atmospheric mineral dust emission mechanisms

    Science.gov (United States)

    Tollerud, H. J.; Fantle, M. S.

    2011-12-01

    Atmospheric mineral dust has a wide range of impacts, including the transport of elements in geochemical cycles, health hazards from small particles, and climate forcing via the reflection of sunlight from dust particles. In particular, the mineral dust component of climate forcing is one of the most uncertain elements in the IPCC climate forcing summary. Mineral dust is also an important component of geochemical cycles. For instance, dust inputs to the ocean potentially affect the iron cycle by stimulating natural iron fertilization, which could then modify climate via the biological pump. Also dust can transport nutrients over long distances and fertilize nutrient-poor regions, such as island ecosystems or the Amazon rain forest. However, there are still many uncertainties in quantifying dust emissions from source regions. One factor that influences dust emission is surface roughness and texture, since a weak, unconsolidated surface texture is more easily ablated by wind than a strong, hard crust. We are investigating the impact of processes such as precipitation, groundwater evaporation, and wind on surface roughness in a playa dust source region. We find that water has a significant influence on surface roughness. We utilize ESA's Advanced Synthetic Aperture Radar (ASAR) instrument to measure roughness in the playa. A map of roughness indicates where the playa surface is smooth (on the scale of centimeters) and potentially very strong, and where it is rough and might be more sensitive to disturbance. We have analyzed approximately 40 ASAR observations of the Black Rock Desert from 2007-2011. In general, the playa is smoother and more variable over time relative to nearby areas. There is also considerable variation within the playa. While the playa roughness maps changed significantly between summers and between observations during the winters, over the course of each summer, the playa surface maintained essentially the same roughness pattern. This suggests that

  8. The Impact of Upstream Flow on the Atmospheric Boundary Layer in a Valley on a Mountainous Island

    Science.gov (United States)

    Adler, Bianca; Kalthoff, Norbert

    2016-03-01

    Comprehensive measurements on the mountainous island of Corsica were used to investigate how the mountain atmospheric boundary layer (mountain ABL) in a valley downstream of the main mountain ridge was influenced by the upstream flow. The data used were mainly collected with the mobile observation platform KITcube during the first special observation period of the Hydrological cycle in the Mediterranean Experiment (HyMeX) in 2012 and were based on various in situ, remote sensing and aircraft measurements. Two days in autumn 2012 were analyzed in detail. On these days the mountain ABL evolution was a result of convection and thermally-driven circulations as well as terrain-induced dynamically-driven flows. During periods when dynamically-driven flows were dominant, warm and dry air from aloft with a large-scale westerly wind component was transported downwards into the valley. On one day, these flows controlled the mountain ABL characteristics in a large section of the valley for several hours, while on the other day their impact was observed in a smaller section of the valley for about 1 h only. To explain the observations we considered a theoretical concept based on uniform upstream stratification and wind speed, and calculated the non-dimensional mountain height and the horizontal aspect ratio of the barrier to relate the existing conditions to diagnosed regimes of stratified flow past a ridge. On both days, wave breaking, flow splitting and lee vortices were likely to occur. Besides the upstream conditions, a reduction of stability in the valley seemed to be important for the downward transport to reach the ground. The spatio-temporal structure of such a mountain ABL over complex terrain, which was affected by various interacting flows, differed a lot from that of the classical ABL over homogeneous, flat terrain and it is stressed that the traditional ABL definitions need to be revised when applying them to complex terrain.

  9. Atmospheric particulate matter in proximity to mountaintop coal mines: Sources and potential environmental and human health impacts

    Science.gov (United States)

    Kurth, Laura; Kolker, Allan; Engle, Mark A.; Geboy, Nicholas J.; Hendryx, Michael; Orem, William H.; McCawley, Michael; Crosby, Lynn M.; Tatu, Calin A.; Varonka, Matthew S.; DeVera, Christina A.

    2015-01-01

    Mountaintop removal mining (MTM) is a widely used approach to surface coal mining in the US Appalachian region whereby large volumes of coal overburden are excavated using explosives, removed, and transferred to nearby drainages below MTM operations. To investigate the air quality impact of MTM, the geochemical characteristics of atmospheric particulate matter (PM) from five surface mining sites in south central West Virginia, USA, and five in-state study control sites having only underground coal mining or no coal mining whatsoever were determined and compared. Epidemiologic studies show increased rates of cancer, respiratory disease, cardiovascular disease, and overall mortality in Appalachian surface mining areas compared to Appalachian non-mining areas. In the present study, 24-h coarse (>2.5 µm) and fine (≤2.5 µm) PM samples were collected from two surface mining sites in June 2011 showed pronounced enrichment in elements having a crustal affinity (Ga, Al, Ge, Rb, La, Ce) contributed by local sources, relative to controls. Follow-up sampling in August 2011 lacked this enrichment, suggesting that PM input from local sources is intermittent. Using passive samplers, dry deposition total PM elemental fluxes calculated for three surface mining sites over multi-day intervals between May and August 2012 were 5.8 ± 1.5 times higher for crustal elements than at controls. Scanning microscopy of 2,249 particles showed that primary aluminosilicate PM was prevalent at surface mining sites compared to secondary PM at controls. Additional testing is needed to establish any link between input of lithogenic PM and disease rates in the study area.

  10. Effect of chemical elicitors on peppermint (Mentha piperita) plants and their impact on the metabolite profile and antioxidant capacity of resulting infusions.

    Science.gov (United States)

    Figueroa Pérez, Marely G; Rocha-Guzmán, Nuria Elizabeth; Mercado-Silva, Edmundo; Loarca-Piña, Guadalupe; Reynoso-Camacho, Rosalía

    2014-08-01

    Infusions are widely consumed all over the world and are a source of dietary antioxidants, which can be improved in plants using elicitors. The aim of this study was to evaluate the foliar application of salicylic acid (SA) (0.5, 1 and 2mM) or hydrogen peroxide (H2O2) (0.05, 0.1 and 0.5mM) on peppermint (Mentha piperita) plants and its effect on the metabolite profile and antioxidant capacity of resulting infusions. Whereas 2mM SA treatment improved plant growth parameters and metabolite profile (carbohydrates and amino acids), 0.5 and 1mM SA treatments increased phenolic compound concentration. Sinapic acid, rutin and naringin were detected only in SA treatments; antioxidant capacity was also improved. Regarding H2O2 treatments, no differences in plant growth parameters, metabolite profile or antioxidant capacity were found. Therefore, the application of SA to peppermint is recommended in order to improve bioactive compounds and the antioxidant capacity of infusions.

  11. Assessment of impact of a severe accident at nuclear power plant of Angra dos Reis with release of radionuclides to the atmosphere

    International Nuclear Information System (INIS)

    This study had as purpose the assess the impact of a severe accident, and also analyze the dispersion of 131I in the atmosphere, so that, through concentrating and inhaling dose of the plume, were possible to verify if the results are in accordance with the indicated data by the Plan of Emergency of the CNAAA regarding the Impact Zone and Control. This exercise was performed with the aid of an atmospheric model and a dispersion where to atmospheric modeling we used the data coupling WRF / CALMET and of dispersion, CALPUFF. The suggested accident consists of a Station Blackout at Nuclear Power of Angra (Unit 1), where through the total core involvement, will release 100% of the 131I to the atmosphere. The value of the total activity in the nucleus to this radionuclide is 7.44 x 1017 Bq, that is relative on the sixth day of burning. This activity will be released through the chimney at a rate in Bq/s in the scenario of 12, 24, 48 and 72 hours of release. Applying the model in the proposed scenario, it is verified that the plume has concentrations of the order of 1020 Bq/m³ and dose of about 108 Sv whose value is beyond of the presented by Eletronuclear in your current emergency plan. (author)

  12. Evaluation of the atmospheric stability and it influence in the radiological environmental impact of the treatment plant and radioactive waste storage (PTDR)

    International Nuclear Information System (INIS)

    It is well-known that the meteorological variables as the atmospheric stability, influence in the atmospheric dispersion of radioactive pollutants, for that as regards radiological safety, it constitutes a demand the evaluation of their impact in the process before mentioned. The present work exposes the results of the study of the radiological impact of our PTDR that it allowed to know the influence of this meteorological parameter in the atmospheric dispersion of radioactive pollutants in its location. To such effects they were processed by means of the methodology of Pasquill - Gifford, data of time zone observations of this meteorological variable obtained in the proximities of the installation, being modeled the worst conditions in atmospheric liberation of their radionuclides inventory, valuing stops the 2 critical considered population groups the doses received by inhalation of polluted air and ingestion of water and polluted products, as well as, for external irradiation from the radioactive cloud and the floor. The obtained annual effective doses due to the modeling situation reach until a mSv, except for the Ra-226 that are lightly superior, implying a risk radiological acceptable chord to the international standard. To the above-mentioned a reduced probability of occurrence of events initiators of the evaluated accidental sequence is added. (Author)

  13. Antioxidant effects and impact on human health of astaxanthin%虾青素的抗氧化作用及对人体健康的影响

    Institute of Scientific and Technical Information of China (English)

    彭亮; 赵鹏; 李彬; 张洁宏; 黄超培

    2011-01-01

    Objective To research the antioxitant effets and impact on human health of astaxanthin.Methods One hundred and twenty healthy volunteers were divided into test group and control group by random according to the content of serum MDA.Subjects in the test group were orally given astaxanthin consecutively for 90 day.MDA contents, SOD and GSH-Px activities and indexes for the safety of astaxanthin were determined at the 90th day of the trial.Results Comparing with the control group, MDA contents in the test group decreased significantly ( P < 0.01 ), and SOD and GSHPx activities increased significantly (P < 0.01 ).All safety indexes were in normal range.Conclusion The antioxidative function might be improved by astaxanthin and no toxicity was observed in human body.%目的 探讨虾青素的抗氧化作用和对人体健康的影响.方法 将120名健康志愿者按血清丙二醛含量随机分为试食组和对照组,试食组连续服用受试物90 d,对照组服用安慰剂,测定两组人群血清中丙二醛(MDA)含量及超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性和安全性指标.结果 试食组血清MDA含量显著下降,与对照组的差异有统计学意义(P<0.01),试食组血清SOD和GSH-Px活性显著升高,与对照组的差异有统计学意义(P<0.01).试验前后两组人群的各项安全性指标均在正常范围内.结论 虾青素可提高人体的抗氧化能力,且对人体健康无损害作用.

  14. Multi-model simulations of the impact of international shipping on Atmospheric Chemistry and Climate in 2000 and 2030

    Directory of Open Access Journals (Sweden)

    V. Eyring

    2007-01-01

    Full Text Available The global impact of shipping on atmospheric chemistry and radiative forcing, as well as the associated uncertainties, have been quantified using an ensemble of ten state-of-the-art atmospheric chemistry models and a pre-defined set of emission data. The analysis is performed for present-day conditions (year 2000 and for two future ship emission scenarios. In one scenario ship emissions stabilize at 2000 levels; in the other ship emissions increase with a constant annual growth rate of 2.2% up to 2030 (termed the "Constant Growth Scenario" (CGS. Most other anthropogenic emissions follow the IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios A2 scenario, while biomass burning and natural emissions remain at year 2000 levels. An intercomparison of the model results with observations over the Northern Hemisphere (25°–60° N oceanic regions in the lower troposphere showed that the models are capable to reproduce ozone (O3 and nitrogen oxides (NOx=NO+NO2 reasonably well, whereas sulphur dioxide (SO2 in the marine boundary layer is significantly underestimated. The most pronounced changes in annual mean tropospheric NO2 and sulphate columns are simulated over the Baltic and North Seas. Other significant changes occur over the North Atlantic, the Gulf of Mexico and along the main shipping lane from Europe to Asia, across the Red and Arabian Seas. Maximum contributions from shipping to annual mean near-surface O3 are found over the North Atlantic (5–6 ppbv in 2000; up to 8 ppbv in 2030. Ship contributions to tropospheric O3 columns over the North Atlantic and Indian Oceans reach 1 DU in 2000 and up to 1.8 DU in 2030. Tropospheric O3 forcings due to shipping are 9.8±2.0 mW/m2 in 2000 and 13.6±2.3 mW/m2 in 2030. Whilst increasing O3, ship NOx simultaneously enhances hydroxyl radicals over the remote ocean, reducing the global methane lifetime by 0.13 yr in 2000, and by up to 0.17 yr in 2030, introducing a

  15. Characterization of Early Stage Marcellus Shale Development Atmospheric Emissions and Regional Air Quality Impacts using Fast Mobile Measurements

    Science.gov (United States)

    Goetz, J. D.; Floerchinger, C. R.; Fortner, E.; Wormhoult, J.; Massoli, P.; Herndon, S. C.; Kolb, C. E., Jr.; Knighton, W. B.; Shaw, S. L.; Knipping, E. M.; DeCarlo, P. F.

    2014-12-01

    The Marcellus shale is the largest shale gas resource in the United States and is found in the Appalachian region. Rapid large-scale development, and the scarcity of direct air measurements make the impact of Marcellus shale development on local and regional air quality and the global climate highly uncertain. Air pollutant and greenhouse gas emission sources include transitory emission from well pad development as well as persistent sources including the processing and distribution of natural gas. In 2012, the Aerodyne Inc. Mobile Laboratory was equipped with a suite of real-time (~ 1 Hz) instrumentation to measure source emissions associated with Marcellus shale development and to characterize regional air quality in the Marcellus basin. The Aerodyne Inc. Mobile Laboratory was equipped to measure methane, ethane, N2O (tracer gas), C2H2 (tracer gas), CO2, CO, NOx, aerosols (number, mass, and composition), and VOC including light aromatic compounds and constituents of natural gas. Site-specific emissions from Marcellus shale development were quantified using tracer release ratio methods. Emissions of sub-micron aerosol mass and VOC were generally not observed at any tracer release site, although particle number concentrations were often enhanced. Compressor stations were found to have the largest emission rates of combustion products with NOx emissions ranging from 0.01 to 1.6 tons per day (tpd) and CO emissions ranging from 0.03 to 0.42 tpd. Transient sources, including a well site in the drill phase, were observed to be large emitters of natural gas. The largest methane emissions observed in the study were at a flowback well completion with a value of 7.7 tpd. Production well pads were observed to have the lowest emissions of natural gas and the emission of combustion products was only observed at one of three well pads investigated. Regional background measurements of all measured species were made while driving between tracer release sites and while stationary

  16. Emission of CO2 by the transport sector and the impact on the atmospheric concentration in Sao Paulo, Brazil.

    Science.gov (United States)

    Andrade, M. D. F.; Kitazato, C.; Perez-Martinez, P.; Nogueira, T.

    2014-12-01

    The Metropolitan Area of São Paulo (MASP) is impacted by the emission of 7 million vehicles, being 85% light-duty vehicles (LDV), 3% heavy-duty diesel vehicles (HDV)s, and 12% motorcycles. About 55% of LDVs burn a mixture of 78% gasoline and 22% ethanol (gasohol), 4% use hydrous ethanol (95% ethanol and 5% water), 38% are flex-fuel vehicles that are capable of burning both gasohol and hydrous ethanol and 3% use diesel (diesel + 5% bio-diesel). The owners of the flex-fuel vehicles decide to use ethanol or gasohol depending on the market price of the fuel. Many environmental programs were implemented to reduce the emissions by the LDV and HDV traffic; the contribution from the industrial sector has been decreasing as the industries have moved away from MASP, due to the high taxes applied to the productive sector. Due to the large contribution of the transport sector to CO2, its contribution is important in a regional scale. The total emission is estimated in 15327 million tons per year of CO2eq (60% by LDV, 38% HDV and 2% motorcycles). Measurements of CO2 performed with a Picarro monitor based on WS-CRDS (wavelength-scanned cavity ringdown spectroscopy) for the years 2012-2013 were performed. The sampling site was on the University of Sao Paulo campus (22o34´S, 46o44´W), situated in the west area of the city, surrounded by important traffic roads. The average data showed two peaks, one in the morning and the other in the afternoon, both associated with the traffic. Correlation analysis was performed between the concentrations and the number of vehicles, as a proxy for the temporal variation of the CO2 emission. The highest concentration was 430 ppm at 8:00am, associated to the morning peak hour of vehicles and the stable condition of the atmosphere. The average concentration was 406 ±12 ppm, considering all measured data. According to official inventories from the Environmental Agency (CETESB), the emission of CO2 has increased 39% from 1990 to 2008, associated

  17. Impact of atmospheric and physical forcings on biogeochemical cycling of dissolved oxygen and nutrients in the coastal Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Sridevi, B.; Maneesha, K.; Sridevi, T.; Naidu, S.A; Prasad, V.R.; Venkataramana, V.; Acharya, T.; Bharati, M.D.; Subbaiah, C.V.; Kiran, B.S.; Reddy, N.P.C.; Sarma, V.V.; Sadhuram, Y.; Murty, T.V.R.

    study periods. High concentrations of chlorophyll-a and nutrients were associated with the extreme atmospheric events. The strong relationship of nutrients with salinity indicates that physical processes, such as circulation, mixing and river discharge...

  18. Forum on impact of radioactive materials on the atmospheric pollutant inventory and on the radioactivity uptake by plants

    International Nuclear Information System (INIS)

    This report contains 6 separately documented lectures about the following topics of the meeting: 1) Radiation exposure of plants caused by the reactor accident of Chernobyl; 2) Tritium and radiocarbon concentrations in trees; 3) Energetics of the atmospheric trace materials cycle; 4) Phenomenology of formation and decomposition of ozone in the lower atmosphere, and 5) Comparison of radioactivity levels and trace materials in the air. (PW)

  19. Impact of atmospheric forcing on heat content variability in the sub-surface layer in the Japan/East Sea, 1948-2009

    Science.gov (United States)

    Stepanov, Dmitry; Gusev, Anatoly; Diansky, Nikolay

    2016-04-01

    Based on numerical simulations the study investigates impact of atmospheric forcing on heat content variability of the sub-surface layer in Japan/East Sea (JES), 1948-2009. We developed a model configuration based on a INMOM model and atmospheric forcing extracted from the CORE phase II experiment dataset 1948-2009, which enables to assess impact of only atmospheric forcing on heat content variability of the sub-surface layer of the JES. An analysis of kinetic energy (KE) and total heat content (THC) in the JES obtained from our numerical simulations showed that the simulated circulation of the JES is being quasi-steady state. It was found that the year-mean KE variations obtained from our numerical simulations are similar those extracted from the SODA reanalysis. Comparison of the simulated THC and that extracted from the SODA reanalysis showed significant consistence between them. An analysis of numerical simulations showed that the simulated circulation structure is very similar that obtained from the PALACE floats in the intermediate and abyssal layers in the JES. Using empirical orthogonal function analysis we studied spatial-temporal variability of the heat content of the sub-surface layer in the JES. Based on comparison of the simulated heat content variations with those obtained from natural observations an assessment of the atmospheric forcing impact on the heat content variability was obtained. Using singular value decomposition analysis we considered relationships between the heat content variability and wind stress curl as well as sensible heat flux in winter. It was established the major role of sensible heat flux in decadal variability of the heat content of the sub-surface layer in the JES. The research was supported by the Russian Foundation for Basic Research (grant N 14-05-00255) and the Council on the Russian Federation President Grants (grant N MK-3241.2015.5)

  20. Using the model release ARTM associated with resources for simulation geoprocessing radiological environmental impact of atmospheric emissions from a research reactor

    International Nuclear Information System (INIS)

    The knowledge of the dispersion of radionuclides emissions into the atmosphere arising from a nuclear reactor, in normal operation, is an important step in the process of the nuclear and environmental assessment study. These processes require an assessment study of the radiological environmental impact. However, to estimate this impact a simulation of the transport mechanisms and deposition of pollutants released into the atmosphere is required. The present study aimed at the application of the dispersion model ARTM (Atmospheric Radionuclide Transport Model), together with the powerful tools of the GIS (Geographic Information System) for the environmental impact assessment of a radiological nuclear reactor under typically routine and conditions. Therefore some important information from the national project for a research reactor known as Brazilian Multipurpose Reactor (RMB) was considered. The information of the atmospheric emissions of the reactor, needed for the simulation of this project, was based on data of the Open Pool Australian Light Water (OPAL).Other important data that had to be collected and analyzed were the source term, the topography, the meteorology and the environmental data. The radionuclides analyzed as pollutants were 41Ar; 140Ba; 51Cr; 137Cs; 131I; 133I; 85m Kr; 87Kr; 88Kr; 140La; 133Xe; 135Xe; 3H; 90Sr. The model was run for two chronological scenarios according to their meteorological data for the years 2009 and 2010, respectively. The adoption of GIS techniques was relevant in planning, data preprocessing and in the post-processing of results as well. After pre-processing, the input data were processed by the ARTM dispersion model. Maps, charts, and tables were then produced and evaluated. According to the simulated and evaluated scenarios it could be concluded that exposure pathways that mostly contributed to the dose for individual public were 41Ar, for immersion in the plume, and 133I, for inhalation. Nevertheless, even these pathways

  1. Impact of Atmospheric Plasma Generated by a DBD Device on Quality-Related Attributes of "Abate Fetel" Pear Fruit

    Science.gov (United States)

    Berardinelli, Annachiara; Vannini, Lucia; Ragni, Luigi; Guerzoni, M. Elisabetta

    The effects of gas plasma generated by a Dielectric Barrier Discharge (DBD) device on "Abate Fetel" fresh pears were assessed following exposure times from 10 to 90 min. In particular the decontamination efficacy towards the indigenous microflora naturally occurring on the surface of the fruit was evaluated. The main results showed that total mesophilic bacteria, yeasts and moulds had different inactivation dynamics. However, maximum cell decreases of 2.5 Log CFU/fruit were achieved for all the microbial groups after 90 min of treatment at a relative humidity level of 60% (22°C). Immediately after the treatments, no significant effects were observed on the measured quality traits. After storage for 5 days at 20°C significant changes were detected only in the peel (colour and antioxidant capacity) of fruit samples treated for 90 min. The Magness-Taylor flesh firmness (MTf), the soluble solid content (SSC) and the antioxidant capacity of fruits were unaffected by the tested treatments.

  2. Antioxidant activity of medicinal, aromatic and culinary herbs from organic and conventional farming

    OpenAIRE

    Sabolová, Monika

    2012-01-01

    The constant attempting of a comeback to the nature has its impact in food industry and agriculture. People prefer natural antioxidants that are considered as less dangerous to health than synthetic antioxidants. Herbs are very suitable as natural antioxidants due to the production of substances (secondary metabolites) that have antioxidant effect and can be easily used as food antioxidants. The reason for strengthening of nature may be the rising preferences of products in ecological...

  3. Antioxidant-Induced Stress

    Directory of Open Access Journals (Sweden)

    Robert D. Kross

    2012-02-01

    Full Text Available Antioxidants are among the most popular health-protecting products, sold worldwide without prescription. Indeed, there are many reports showing the benefits of antioxidants but only a few questioning the possible harmful effects of these “drugs”. The normal balance between antioxidants and free radicals in the body is offset when either of these forces prevails. The available evidence on the harmful effects of antioxidants is analyzed in this review. In summary, a hypothesis is presented that “antioxidant-induced stress” results when antioxidants overwhelm the body’s free radicals.

  4. The impact of temperature dependent CO2 cross section measurements: A role for heterogeneous chemistry in the atmosphere of Mars?

    Science.gov (United States)

    Anbar, A. D.; Allen, M.; Nair, H.; Leu, M-T.; Yung, Y. L.

    1992-01-01

    Carbon dioxide comprises over 95 percent of the Mars atmosphere, despite continuous photolysis of CO2 by solar ultraviolet (UV) radiation. Since the direct recombination of CO and O is spinforbidden, the chemical stability of CO2 in the Martian atmosphere is thought to be the result of a HO(x)-catalyzed recombination scheme. Thus the rate of CO oxidation is sensitive to the abundance and altitude distribution of OH, H, and HO2. Most Martian atmospheric models assume that HO(x) abundances are governed purely by gas phase chemistry. However, it is well established that reactive HO(x) radical are adsorbed by a wide variety of surfaces. The authors have combined laboratory studies of H, OH, and HO2 adsorption on inorganic surfaces, observational data of aerosol distributions, and an updated photochemical model to demonstrate that adsorption on either dust or ice aerosols is capable of reducing HO(x) abundances significantly, thereby retarding the rate of CO oxidation.

  5. A Model Study of the Impact of Magnetic Field Reversal on Atmospheric Composition during Solar Proton Events

    Science.gov (United States)

    Sinnhuber, Miaiam; Jackman, Charles H.; Burrows, John P.; Chipperfield, Martyn P.; Kallenrode, May-Britt; Kunzi, Klaus F.; Quack, Manual

    2003-01-01

    During a polarity transition of the Earth's magnetic field, the structure and strength of the field change significantly from their present values. This will alter the global pattern of charged particle precipitation into the atmosphere. Thus, particle precipitation is possible into regions that are at the moment effectively shielded by the Earth's magnetic field. A two-dimensional global fbHy coupled chemistry, radiation, and transport model of the atmosphere has been used to investigate how the increased particle precipitation affects the chemical composition of the middle and lower atmosphere. Ozone losses resulting from large energetic particle events are found to increase significantly, with resultant losses similar to those observed m the Antarctic ozone hole of the 1990s. This results in significant increases in surface UV-B radiation as well as changes in stratospheric temperature and circulation over a period of several months after large particle events.

  6. Impacts of lindane usage in the Canadian prairies on the Great Lakes ecosystem. 1. Coupled atmospheric transport model and modeled concentrations in air and soil.

    Science.gov (United States)

    Ma, Jianmin; Daggupaty, Sreerama; Harner, Tom; Li, Yifan

    2003-09-01

    A coupled atmospheric transport, soil-air, water-air exchange model was developed to investigate the impacts of gamma-hexachlorocyclohexane (gamma-HCH or lindane) usage in the Canadian prairies over the Great Lakes region. The fate of gamma-HCH in air and soil is governed by atmospheric dynamics and physical and chemical processes that are described by the coupled model. These processes include transport and turbulent diffusion in the atmosphere, dry and wet deposition, exchange at the interfacial boundaries of air-water and soil-air, and removal processes from the soil such as diffusion, leaching, and degradation. Numerical experiments were conducted for the period of May 1, 1998-April 30, 1999, starting with application of lindane in the spring. The coupled model was executed with two lindane emission (usage) inventories in the model domain. The first scenario contained all known fresh emission sources in Canada-98% was usage in the prairies; the second excluded emission sources from Ontario and Quebec. The model showed that, in the absence of the reemission from past application of lindane, usage of lindane in Ontario and Quebec has a negligible impact on air concentrations in these regions and that the lindane budget in the Great Lakes ecosystem is mostly attributed to applications of lindane in the canola fields in Canadian prairie provinces. Model-predicted air concentrations and seasonal trends agreed well with measured data over the same time period for several background sites operated under the Integrated Atmospheric Deposition Network. Air temperature was shown to play a key role on surface-air exchange dynamics of gamma-HCH. A future paper will assess loadings to the Great Lakes based on these validated model results. PMID:12967095

  7. GLANCE - calculatinG heaLth impActs of atmospheric pollutioN in a Changing climatE

    Science.gov (United States)

    Vogel, Leif; Faria, Sérgio; Markandya, Anil

    2016-04-01

    Current annual global estimates of premature deaths from poor air quality are estimated in the range of 2.6-4.4 million, and 2050 projections are expected to double against 2010 levels. In Europe, annual economic burdens are estimated at around 750 bn €. Climate change will further exacerbate air pollution burdens; therefore, a better understanding of the economic impacts on human societies has become an area of intense investigation. European research efforts are being carried out within the MACC project series, which started in 2005. The outcome of this work has been integrated into a European capacity for Earth Observation, the Copernicus Atmospheric Monitoring Service (CAMS). In MACC/CAMS, key pollutant concentrations are computed at the European scale and globally by employing chemically-driven advanced transport models. The project GLANCE (calculatinG heaLth impActs of atmospheric pollutioN in a Changing climatE) aims at developing an integrated assessment model for calculating the health impacts and damage costs of air pollution at different physical scales. It combines MACC/CAMS (assimilated Earth Observations, an ensemble of chemical transport models and state of the art ECWMF weather forecasting) with downscaling based on in-situ network measurements. The strengthening of modelled projections through integration with empirical evidence reduces errors and uncertainties in the health impact projections and subsequent economic cost assessment. In addition, GLANCE will yield improved data accuracy at different time resolutions. This project is a multidisciplinary approach which brings together expertise from natural sciences and socio economic fields. Here, its general approach will be presented together with first results for the years 2007 - 2012 on the European scale. The results on health impacts and economic burdens are compared to existing assessments.

  8. Impact of Manaus City on the Amazon Green Ocean atmosphere: Ozone production, precursor sensitivity and aerosol load

    NARCIS (Netherlands)

    Kuhn, U.; Ganzeveld, L.N.

    2010-01-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry sea

  9. Impact of sulfate nutrition on the utilization of atmospheric SO2 as sulfur source for Chinese cabbage

    NARCIS (Netherlands)

    Yang, Liping; Stulen, I.; De Kok, L.J.

    2006-01-01

    The ability of Chinese cabbage (Brassica pekinensis) to utilize atmospheric sulfur dioxide (SO2) as sulfur (S) source for growth was investigated in relation to root sulfate (SO42-) nutrition. If seedlings of Chinese cabbage were transferred to a sulfate-deprived nutrient solution directly after ger

  10. Improving ecophysiological simulation models to predict the impact of elevated atmospheric CO2 concentration on crop productivity

    NARCIS (Netherlands)

    Yin, X.

    2013-01-01

    Background - Process-based ecophysiological crop models are pivotal in assessing responses of crop productivity and designing strategies of adaptation to climate change. Most existing crop models generally over-estimate the effect of elevated atmospheric [CO2], despite decades of experimental resear

  11. Atmospheric H2S and SO2 as sulfur source for Brassica juncea and Brassica rapa: impact on the glucosinolate composition

    OpenAIRE

    Aghajanzadeh, Tahereh; Kopriva, Stanislav; Malcolm J Hawkesford; Koprivova, Anna; De Kok, Luit J.

    2015-01-01

    The impact of sulfate deprivation and atmospheric H2S and SO2 nutrition on the content and composition of glucosinolates was studied in Brassica juncea and B. rapa. Both species contained a number of aliphatic, aromatic and indolic glucosinolates. The total glucosinolate content was more than 5.5-fold higher in B. juncea than in B. rapa, which could solely be attributed to the presence of high levels of sinigrin, which was absent in the latter species. Sulfate deprivation resulted in a strong...

  12. Electron impact cross-sections and cooling rates for methane. [in thermal balance of electrons in atmospheres and ionospheres of planets and satellites in outer solar system

    Science.gov (United States)

    Gan, L.; Cravens, T. E.

    1992-01-01

    Energy transfer between electrons and methane gas by collisional processes plays an important role in the thermal balance of electrons in the atmospheres and ionospheres of planets and satellites in the outer solar system. The literature is reviewed for electron impact cross-sections for methane in this paper. Energy transfer rates are calculated for elastic and inelastic processes using a Maxwellian electron distribution. Vibrational, rotational, and electronic excitation and ionization are included. Results are presented for a wide range of electron temperatures and neutral temperatures.

  13. Antioxidant-Induced Stress

    OpenAIRE

    Robert D. Kross; Cleva Villanueva

    2012-01-01

    Antioxidants are among the most popular health-protecting products, sold worldwide without prescription. Indeed, there are many reports showing the benefits of antioxidants but only a few questioning the possible harmful effects of these “drugs”. The normal balance between antioxidants and free radicals in the body is offset when either of these forces prevails. The available evidence on the harmful effects of antioxidants is analyzed in this review. In summary, a hypothesis is presented that...

  14. Coupling atmospheric mercury isotope ratios and meteorology to identify sources of mercury impacting a coastal urban-industrial region near Pensacola, Florida, USA

    Science.gov (United States)

    Demers, Jason D.; Sherman, Laura S.; Blum, Joel D.; Marsik, Frank J.; Dvonch, J. Timothy

    2015-10-01

    Identifying the anthropogenic and natural sources of mercury (Hg) emissions contributing to atmospheric mercury on local, regional, and global scales continues to be a grand challenge. The relative importance of various direct anthropogenic emissions of mercury, in addition to natural geologic sources and reemission of previously released and deposited mercury, differs regionally and temporally. In this study, we used local-scale, mesoscale, and synoptic-scale meteorological analysis to couple the isotopic composition of ambient atmospheric mercury with potential sources of mercury contributing to a coastal urban-industrial setting near a coal-fired power plant in Pensacola, Florida, USA. We were able to broadly discern four influences on the isotopic composition of ambient atmospheric mercury impacting this coastal urban-industrial region: (1) local to regional urban-industrial anthropogenic emissions (mean δ202Hg = 0.44 ± 0.05‰, 1SD, n = 3), (2) marine-influenced sources derived from the Gulf of Mexico (mean δ202Hg = 0.77 ± 0.15‰, 1SD, n = 4), (3) continental sources associated with north-northwesterly flows from within the planetary boundary layer (mean δ202Hg = 0.65 ± 0.04‰, 1SD, n = 3), and (4) continental sources associated with north-northeasterly flows at higher altitudes (i.e., 2000 m above ground level; mean δ202Hg = 1.10 ± 0.21‰, 1SD, n = 8). Overall, these data, in conjunction with previous studies, suggest that the background global atmospheric mercury pool is characterized by moderately positive δ202Hg values; that urban-industrial emissions drive the isotopic composition of ambient atmospheric mercury toward lower δ202Hg values; and that air-surface exchange dynamics across vegetation and soils of terrestrial ecosystems drive the isotopic composition of ambient atmospheric mercury toward higher positive δ202Hg values. The data further suggest that mass-independent fractionation (MIF) of both even-mass- and odd-mass-number isotopes

  15. First Results from the ASIBIA (Arctic Sea-Ice, snow, Biogeochemistry and Impacts on the Atmosphere) Sea-Ice Chamber

    Science.gov (United States)

    Frey, M. M.; France, J.; von Glasow, R.; Thomas, M.

    2015-12-01

    The ocean-ice-atmosphere system is very complex, and there are numerous challenges with conducting fieldwork on sea-ice including costs, safety, experimental controls and access. By creating a new coupled Ocean-Sea-Ice-(Snow)-Atmosphere facility at the University of East Anglia, UK, we are able to perform controlled investigations in areas such as sea-ice physics, physicochemical and biogeochemical processes in sea-ice, and to quantify the bi-directional flux of gases in established, freezing and melting sea-ice. The environmental chamber is capable of controlled programmable temperatures from -55°C to +30°C, allowing a full range of first year sea-ice growing conditions in both the Arctic and Antarctic to be simulated. The sea-ice tank within the chamber measures 2.4 m x 1.4 m x 1 m water depth, with an identically sized Teflon film atmosphere on top of the tank. The tank and atmosphere forms a coupled, isolated mesocosm. Above the atmosphere is a light bank with dimmable solar simulation LEDs, and UVA and UVB broadband fluorescent battens, providing light for a range of experiments such as under ice biogeochemistry and photochemistry. Ice growth in the tank will be ideally suited for studying first-year sea-ice physical properties, with in-situ ice-profile measurements of temperature, salinity, conductivity, pressure and spectral light transmission. Under water and above ice cameras are installed to observe the physical development of the sea-ice. The ASIBIA facility is also well equipped for gas exchange and diffusion studies through sea-ice with a suite of climate relevant gas measuring instruments (CH4, CO2, O3, NOx, NOy permanently installed, further instruments available) able to measure either directly in the atmospheric component, or via a membrane for water side dissolved gases. Here, we present the first results from the ASIBIA sea-ice chamber, focussing on the physical development of first-year sea-ice and show the future plans for the facility over

  16. Antioxidants in dermatology

    Directory of Open Access Journals (Sweden)

    Varadraj V Pai

    2014-01-01

    Full Text Available Antioxidants neutralize free radicals produced by various environmental insults such as ultraviolet radiation, cigarette smoke and air pollutants, thereby preventing cellular damage. The role of oxidative stress and antioxidants is known in diseases like obesity, atherosclerosis, and Alzheimer′s disease. Herein we discuss the effects of oxidative stress on the skin and role of antioxidants in dermatology.

  17. Antioxidants in dermatology

    OpenAIRE

    Varadraj V Pai; Pankaj Shukla; Naveen Narayanshetty Kikkeri

    2014-01-01

    Antioxidants neutralize free radicals produced by various environmental insults such as ultraviolet radiation, cigarette smoke and air pollutants, thereby preventing cellular damage. The role of oxidative stress and antioxidants is known in diseases like obesity, atherosclerosis, and Alzheimer′s disease. Herein we discuss the effects of oxidative stress on the skin and role of antioxidants in dermatology.

  18. Parameterization of dust emissions in the global atmospheric chemistry-climate model EMAC: impact of nudging and soil properties

    Directory of Open Access Journals (Sweden)

    M. Astitha

    2012-11-01

    Full Text Available Airborne desert dust influences radiative transfer, atmospheric chemistry and dynamics, as well as nutrient transport and deposition. It directly and indirectly affects climate on regional and global scales. Two versions of a parameterization scheme to compute desert dust emissions are incorporated into the atmospheric chemistry general circulation model EMAC (ECHAM5/MESSy2.41 Atmospheric Chemistry. One uses a globally uniform soil particle size distribution, whereas the other explicitly accounts for different soil textures worldwide. We have tested these two versions and investigated the sensitivity to input parameters, using remote sensing data from the Aerosol Robotic Network (AERONET and dust concentrations and deposition measurements from the AeroCom dust benchmark database (and others. The two versions are shown to produce similar atmospheric dust loads in the N-African region, while they deviate in the Asian, Middle Eastern and S-American regions. The dust outflow from Africa over the Atlantic Ocean is accurately simulated by both schemes, in magnitude, location and seasonality. Approximately 70% of the modelled annual deposition data and 70–75% of the modelled monthly aerosol optical depth (AOD in the Atlantic Ocean stations lay in the range 0.5 to 2 times the observations for all simulations. The two versions have similar performance, even though the total annual source differs by ~50%, which underscores the importance of transport and deposition processes (being the same for both versions. Even though the explicit soil particle size distribution is considered more realistic, the simpler scheme appears to perform better in several locations. This paper discusses the differences between the two versions of the dust emission scheme, focusing on their limitations and strengths in describing the global dust cycle and suggests possible future improvements.

  19. Assessing the impact of atmospheric stability on locally and remotely sourced aerosols at Richmond, Australia, using Radon-222

    Science.gov (United States)

    Crawford, Jagoda; Chambers, Scott; Cohen, David; Williams, Alastair; Griffiths, Alan; Stelcer, Eduard

    2016-02-01

    A flexible radon-based scheme for the classification of nocturnal stability regimes was used for the interpretation of daily-integrated PM2.5 aerosol observations collected at Richmond, Australia, between 2007 and 2011. Source fingerprint concentrations for the dominant locally and remotely sourced aerosols were analysed by nocturnal radon stability category to characterise the influences of day-to-day changes in daily integrated atmospheric mixing. The fingerprints analysed included: smoke, vehicle exhaust, secondary sulfate and aged industrial sulfur. The largest and most consistent stability influences were observed on the locally sourced pollutants. Based on a 5-year composite, daily integrated concentrations of smoke were almost a factor of 7 higher when nocturnal conditions were classed as "stable" than when they were "near neutral". For vehicle emissions a factor of 4 was seen. However, when the winter months were considered in isolation, it was found that these factors increased to 11.5 (smoke) and 5.5 (vehicle emissions) for daily average concentrations. The changes in concentration of the remotely sourced pollutants with atmospheric stability were comparatively small and less consistent, probably as a result of the nocturnal inversion frequently isolating near-surface observations from non-local sources at night. A similar classification was performed using the commonly-adopted Pasquill-Gifford (PG) stability typing technique based on meteorological parameters. While concentrations of fingerprints associated with locally-sourced pollutants were also shown to be positively correlated with atmospheric stability using the PG classification, this technique was found to underestimate peak pollutant concentrations under stable atmospheric conditions by almost a factor of 2.

  20. Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics.

    Science.gov (United States)

    Drigo, Barbara; Kowalchuk, George A; Knapp, Brigitte A; Pijl, Agata S; Boschker, Henricus T S; van Veen, Johannes A

    2013-02-01

    Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term increases in CO2 have been hypothesized to have subtle effects due to the potential adaptation of soil microorganism to the increased flow of organic C. Here, we studied the effects of prolonged elevated atmospheric CO2 exposure on microbial C flow and microbial communities in the rhizosphere. Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown at defined atmospheric conditions differing in CO2 concentration (350 and 700 ppm) for 3 years. During this period, C flow was assessed repeatedly (after 6 months, 1, 2, and 3 years) by (13) C pulse-chase experiments, and label was tracked through the rhizosphere bacterial, general fungal, and arbuscular mycorrhizal fungal (AMF) communities. Fatty acid biomarker analyses and RNA-stable isotope probing (RNA-SIP), in combination with real-time PCR and PCR-DGGE, were used to examine microbial community dynamics and abundance. Throughout the experiment the influence of elevated CO2 was highly plant dependent, with the mycorrhizal plant exerting a greater influence on both bacterial and fungal communities. Biomarker data confirmed that rhizodeposited C was first processed by AMF and subsequently transferred to bacterial and fungal communities in the rhizosphere soil. Over the course of 3 years, elevated CO2 caused a continuous increase in the (13) C enrichment retained in AMF and an increasing delay in the transfer of C to the bacterial community. These results show that, not only do elevated atmospheric CO2 conditions induce changes in rhizosphere C flow and dynamics but also continue to develop over multiple seasons, thereby affecting terrestrial ecosystems C utilization processes.

  1. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    OpenAIRE

    Sachs, Marius; Schmitt, Adeliene; Peukert, Wolfgang; Wirth, Karl-Ernst

    2014-01-01

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder...

  2. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    Directory of Open Access Journals (Sweden)

    R. A. Scanza

    2014-07-01

    Full Text Available The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4 and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5 embedded in the Community Earth System Model version 1.0.5 (CESM are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05 W m−2 for both CAM4 and CAM5 simulations with mineralogy and compare this both with simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 W m−2 and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 W m−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in-situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.

  3. The present-day and future impact of NOx emissions from subsonic aircraft on the atmosphere in relation to the impact of NOx surface sources

    OpenAIRE

    Valks, P. J. M.; Velders, G.J.M.

    1999-01-01

    The effect of present-day and future NOx emissions from aircraft on the NOx and ozone concentrations in the atmosphere and the corresponding radiative forcing were studied using a three-dimensional chemistry transport model (CTM) and a radiative model. The effects of the aircraft emissions were compared with the effects of the three most important anthropogenic NOx surface sources: road traffic, electricity generation and industrial combustion. From the model results, NOx ...

  4. Investigating the impact of solar proton events on the middle atmosphere on the basis of three dimensional model studies

    International Nuclear Information System (INIS)

    In Bremen, stratospheric and mesospheric models of different complexity are available, including the new Bremen three-dimensional Chemistry and Transport Model (B3dCTM). It combines a state-of-the-art model of stratospheric chemistry with a three-dimensional transport scheme driven by analysed temperatures and wind-fields from ECMWF, covering an altitude range of 10-75 km. During particle events caused by e.g. solar or geomagnetic storms the upper and middle atmosphere will be ionised. This ionisation will start fast ion chemistry reactions which lead to an increase of odd hydrogen (HOx) and nitrogen (NOx) constituents which both destroy ozone in catalytic cycles. NOx is very long-lived in the middle atmosphere and can be transported down into the middle and lower stratosphere especially during polar winter, where it will then effectively destroy ozone. To simulate these particle events, parameterisations of HOx and NOx production as a function of atmospheric ionisation have been implemented into the model, and the model is driven by ionisation rates based on measured proton fluxes. Model studies for different solar proton events have been carried out and results for NOx and ozone are presented

  5. The impact of enhanced atmospheric carbon dioxide on yield, proximate composition, elemental concentration, fatty acid and vitamin C contents of tomato (Lycopersicon esculentum).

    Science.gov (United States)

    Khan, Ikhtiar; Azam, Andaleeb; Mahmood, Abid

    2013-01-01

    The global average temperature has witnessed a steady increase during the second half of the twentieth century and the trend is continuing. Carbon dioxide, a major green house gas is piling up in the atmosphere and besides causing global warming, is expected to alter the physico-chemical composition of plants. The objective of this work was to evaluate the hypothesis that increased CO(2) in the air is causing undesirable changes in the nutritional composition of tomato fruits. Two varieties of tomato (Lycopersicon esculentum) were grown in ambient (400 μmol mol(-1)) and elevated (1,000 μmol mol(-1)) concentration of CO(2) under controlled conditions. The fruits were harvested at premature and fully matured stages and analyzed for yield, proximate composition, elemental concentration, fatty acid, and vitamin C contents. The amount of carbohydrates increased significantly under the enhanced CO(2) conditions. The amount of crude protein and vitamin C, two important nutritional parameters, decreased substantially. Fatty acid content showed a mild decrease with a slight increase in crude fiber. Understandably, the effect of enhanced atmospheric CO(2) was more pronounced at the fully matured stage. Mineral contents of the fruit samples changed in an irregular fashion. Tomato fruit has been traditionally a source of vitamin C, under the experimental conditions, a negative impact of enhanced CO(2) on this source of vitamin C was observed. The nutritional quality of both varieties of tomato has altered under the CO(2) enriched atmosphere.

  6. A Case Study of the Impacts of Dust Aerosols on Surface Atmospheric Variables and Energy Budgets in a Semi-Arid Region of China

    Institute of Scientific and Technical Information of China (English)

    LING Xiao-Lu; GUO Wei-Dong; ZHANG Le; ZHANG Ren-Jian

    2010-01-01

    The authors present a case study investigatingthe impacts of dust aerosols on surface atmospheric variables and energy budgets in a semi-arid region of China.Enhanced observational meteorological data, radiative fluxes, near-surface heat fluxes, and concentrations of dust aerosols were collected from Tongyu station, one of the reference sites of the International Coordinated Energy and Water Cycle Observations Project (CEOP), during a typical dust storm event in June 2006. A comprehensive analysis of these data show that in this semi-arid area, higher wind velocities and a continuously reduced air pressure were identified during the dust storm period.Dust storm events are usually associated with low relative humidity weather conditions, which result in low latent heat flux values. Dust aerosols suspended in the air decrease the net radiation, mainly by reducing the direct solar radiation reaching the land surface. This reduction in net radiation results in a decrease in soil temperatures at a depth of 2 cm. The combination of increased air temperature and decreased soil temperature strengthens the energy exchange of the atmosphere-earth system, increasing the surface sensible heat flux. After the dust storm event,the atmosphere was dominated by higher pressures and was relatively wet and cold. Net radiation and latent heat flux show an evident increase, while the surface sensible heat flux shows a clear decrease.

  7. Impact of synthetic antioxidants on lipid peroxidation of distiller's dried grains with solubles and distiller's corn oil stored under high temperature and humidity conditions.

    Science.gov (United States)

    Hanson, A R; Urriola, P E; Johnston, L J; Shurson, G C

    2015-08-01

    This experiment evaluated the effect of antioxidants, oil content in distiller's dried grains with solubles (DDGS), quality of distiller's corn oil, and storage time on lipid peroxidation. A source of low-oil DDGS (LO-DDGS; 5.0% ether extract [EE], as-fed basis), high-oil DDGS (HO-DDGS; 13.0% EE, as-fed basis), and 2 sources of distiller's corn oil (DCO; 1.20, 0.08, and 0.48% moisture, insoluble impurities, and unsaponifiables [MIU], respectively [DCO-1], and 1.20, 0.01, and 0.10% MIU, respectively [DCO-2]) were obtained. Each of the 4 ingredients was divided into 18 representative subsamples (approximately 908 g for DDGS or 2 kg of DCO). Six subsamples of each ingredient were mixed with either no supplemental antioxidants (CON), Rendox-CQ (REN; 1,000 mg/kg EE; Kemin, Industries, Des Moines, IA), or Santoquin-Q4T (SAN; 1,500 mg/kg EE; Novus International, St. Louis, MO). Each mixture ( = 72) was split into thirds, and 1 portion was immediately frozen at -20°C (d 0). Two portions were stored under hot (38.6 ± 0.1°C) and humid conditions (94.0 ± 0.3% relative humidity) for 14 or 28 d. The MIXED procedure of SAS was used to evaluate the effects of ingredient, antioxidant, storage time, and interactions, with d-0 values used as a covariate. From d 14 to 28, peroxide value (PV), -anisidine value (AnV), and thiobarbituric acid reactive substances (TBARS) of DCO and DDGS increased by 3- to 4-fold ( mEq O/kg oil, respectively) exceeded ( mEq O/kg oil, respectively). Adding REN or SAN ( reduced TBARS and AnV relative to CON (TBARS = 11.0 ± 0.2 mg malondialdehyde Eq/kg oil and AnV = 6.5 ± 0.2) over the entire period (mean of d 14 and 28), but TBARS and AnV did not differ ( > 0.05) between antioxidants (TBARS = 6.1 ± 0.2 and 5.9 ± 0.2 mg malondialdehyde Eq/kg oil, respectively, and AnV = 1.9 ± 0.2 and 1.8 ± 0.2 for REN and SAN, respectively). The PV on d 14 and 28 and overall was less ( mEq O/kg) and was greater for ingredients treated with SAN ( mEq O/kg oil for

  8. The impact of packaging materials on the antioxidant phytochemical stability of aqueous infusions of green tea (Camellia sinensis) and yaupon holly (Ilex vomitoria) during cold storage.

    Science.gov (United States)

    Kim, Youngmok; Welt, Bruce A; Talcott, Stephen T

    2011-05-11

    Ready to drink (RTD) teas are a growing segment in the beverage category, brought about by improvements in the flavor of these products and healthy market trends driven by consumers. The presented results evaluated the antioxidant phytochemical stability of RTD teas from aqueous infusions of traditional green tea (Camellia sinensis) and a botanical tea from yaupon holly (Ilex vomitoria) as influenced by packaging materials during cold storage. Two common packaging materials for RTD products are glass and polyethylene terephthalate (PET) and have been compared to a retortable pouch (RP), an emerging packaging material for various types of food since it is durable, inexpensive, lightweight, and easy to sterilize. Storage stability was then evaluated for each aqueous infusion prepared at 10 g/L at 90 °C for 10 min and evaluated at 3 °C in the absence of light over 12 weeks. Analyses included quantification and characterization of individual polyphenolics by high-performance liquid chromatography-photodiode array and liquid chromatography-electrospray ionization-mass spectrometry as well as changes in total antioxidant capacity. For green tea, concentrations of the three major flavan-3-ols, epigallocatechin gallate, epigallocatechin, and epicatechin gallate were better retained in glass bottles as compared to other packages over 12 weeks. In yaupon holly, chlorogenic acid and its isomers that were the predominant compounds were generally stable in each packaging material, and a 20.6-fold higher amount of saponin was found as compared to green tea, which caused higher stability of flavonol glycosides present in yaupon holly during storage. The antioxidant capacity of green tea was better retained in glass and PET versus RP, whereas no differences were again observed for yaupon holly. Results highlight the superiority of oxygen-impervious glass packaging, but viable alternatives may be utilizable for RTD teas with variable phytochemical compositions. PMID:21434687

  9. Impact of Elevated Carbon Dioxide on Primary, Secondary Metabolites and Antioxidant Responses of Eleais guineensis Jacq. (Oil Palm Seedlings

    Directory of Open Access Journals (Sweden)

    Hawa Z.E. Jaafar

    2012-05-01

    Full Text Available A split plot 3 by 3 experiment was designed to investigate the relationships among production of primary metabolites (soluble sugar and starch, secondary metabolites (total flavonoids, TF; total phenolics, TP, phenylalanine lyase (PAL activity (EC 4.3.1.5, protein and antioxidant activity (FRAP of three progenies of oil palm seedlings, namely Deli AVROS, Deli Yangambi and Deli URT, under three levels of CO2 enrichment (400, 800 and 1,200 µmol·mol−1 for 15 weeks of exposure. During the study, the treatment effects were solely contributed by CO2 enrichment levels; no progenies and interaction effects were observed. As CO2 levels increased from 400 to 1,200 µmol·mol−1, the production of carbohydrate increased steadily, especially for starch more than soluble sugar. The production of total flavonoids and phenolics contents, were the highest under 1,200 and lowest at 400 µmol·mol−1. It was found that PAL activity was peaked under 1,200 µmol·mol−1 followed by 800 µmol·mol−1 and 400 µmol·mol−1. However, soluble protein was highest under 400 µmol·mol−1 and lowest under 1,200 µmol·mol−1. The sucrose/starch ratio, i.e., the indication of sucrose phosphate synthase actvity (EC 2.4.1.14 was found to be lowest as CO2 concentration increased from 400 > 800 > 1,200 µmol·mol−1. The antioxidant activity, as determined by the ferric reducing/antioxidant potential (FRAP activity, increased with increasing CO2 levels, and was significantly lower than vitamin C and α-tocopherol but higher than butylated hydroxytoluene (BHT. Correlation analysis revealed that nitrogen has a significant negative correlation with carbohydrate, secondary metabolites and FRAP activity indicating up-regulation of production of carbohydrate, secondary metabolites and

  10. Assessment of the possible future climatic impact of carbon dioxide increases based on a coupled one-dimensional atmospheric-oceanic model

    International Nuclear Information System (INIS)

    A radiative-convective equilibrium model of the atmosphere has been coupled with a mixed layer model of the ocean to investigate the response of this one-dimensional system to increasing carbon dioxide amounts in the atmosphere. For global mean conditions a surface temperature rise of about 20 K was obtained for a doubling of the carbon dioxide amount, in reasonable agreement with the commonly accepted results of Manabe and Wetherald. This temperature rise was essentially invariant with season and indicates that including a shallow (300 m) ocean slab in this problem does not basically alter previous assessments. While the mixed layer depth of the ocean was only very slightly changed by the temperature increase, which extended throughout the depth of the mixed layer, the impact of this increase on the overall behavior of the ocean warrants further study. A calculation was also made of the temporal variation of the sea surface temperature for three possible carbon dioxide growth rates starting from an initial carbon dioxide content of 300 ppm. This indicated that the thermal inertia of the slab ocean provides a time lag of 8 years in the sea surface temperature response compared to a land situation. This is not considered to be of great significance as regards the likely future climatic impact of carbon dioxide increase

  11. Simulating Changes in Land-Atmosphere Interactions From Expanding Agriculture and Irrigation in India and the Potential Impacts on the Indian Monsoon.

    Science.gov (United States)

    Douglas, E. M.; Beltran-Przekurat, A.; Niyogi, D.; Pielke, R. A.

    2006-05-01

    With over 57 million hectares under irrigation in 2002, India has the largest irrigated agricultural area on the planet. Between 80 and 90% of India's water use goes to support irrigated agriculture. The Indian monsoon belt is a home to a large part of the world's population and agriculture is the major land-use activity in the region. Previous results showed that annual vapor fluxes in India have increased by 17% (340 km3) over that which would be expected from a natural (non-agricultural) land cover. Two-thirds of this increase was attributed to irrigated agriculture. The largest increases in vapor and latent heat fluxes occurred where both cropland and irrigated lands were the predominant contemporary land cover classes (particularly northwest and north-central India). Our current study builds upon this work by evaluating possible changes in near-surface energy fluxes and regional atmospheric circulation patterns resulting from the expansion of irrigated agriculture on the Indian sub-continent using a regional atmospheric model RAMS. We investigate three separate land- use scenarios: Scenario 1, with a potential (pre-agricultural) land cover, Scenario 2: the potential land-cover overlain by cropland and Scenario 3: potential land-cover overlain by cropland and irrigated area. We will assess the impact of agricultural land-cover conversion and intensive irrigation on water and energy fluxes between the land and the atmosphere and how these flux changes may affect regional weather patterns. The simulation period covers July 16-20, 2002 which allow us to assess potential impacts of land-cover changes on the onset of the Indian Monsoon.

  12. Future impact of non-land based traffic emissions on atmospheric ozone and OH – an optimistic scenario and a possible mitigation strategy

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2011-11-01

    Full Text Available The impact of future emissions from aviation and shipping on the atmospheric chemical composition has been estimated using an ensemble of six different atmospheric chemistry models. This study considers an optimistic emission scenario (B1 taking into account e.g. rapid introduction of clean and resource-efficient technologies, and a mitigation option for the aircraft sector (B1 ACARE, assuming further technological improvements. Results from sensitivity simulations, where emissions from each of the transport sectors were reduced by 5%, show that emissions from both aircraft and shipping will have a larger impact on atmospheric ozone and OH in near future (2025; B1 and for longer time horizons (2050; B1 compared to recent time (2000. However, the ozone and OH impact from aircraft can be reduced substantially in 2050 if the technological improvements considered in the B1 ACARE will be achieved.

    Shipping emissions have the largest impact in the marine boundary layer and their ozone contribution may exceed 4 ppbv (when scaling the response of the 5% emission perturbation to 100% by applying a factor 20 over the North Atlantic Ocean in the future (2050; B1 during northern summer (July. In the zonal mean, ship-induced ozone relative to the background levels may exceed 12% near the surface. Corresponding numbers for OH are 6.0 × 105 molecules cm−3 and 30%, respectively. This large impact on OH from shipping leads to a relative methane lifetime reduction of 3.92 (±0.48 on the global average in 2050 B1 (ensemble mean CH4 lifetime is 8.0 (±1.0 yr, compared to 3.68 (±0.47% in 2000.

    Aircraft emissions have about 4 times higher ozone enhancement efficiency (ozone molecules enhanced relative to NOx molecules emitted than shipping emissions, and the maximum impact is found in the UTLS region. Zonal mean aircraft-induced ozone could reach up to 5 ppbv at northern mid- and high latitudes during

  13. Future impact of non-land based traffic emissions on atmospheric ozone and OH – an optimistic scenario and a possible mitigation strategy

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2011-06-01

    Full Text Available The impact of future emissions from aviation and shipping on the atmospheric chemical composition has been estimated using an ensemble of six different atmospheric chemistry models. This study considers an optimistic emission scenario (B1 taking into account e.g. rapid introduction of clean and resource-efficient technologies, and a mitigation option for the aircraft sector (B1 ACARE, assuming further technological improvements. Results from sensitivity simulations, where emissions from each of the transport sectors were reduced by 5 %, show that emissions from both aircraft and shipping will have a larger impact on atmospheric ozone and OH in near future (2025; B1 and for longer time horizons (2050; B1 compared to recent time (2000. However, the ozone and OH impact from aircraft can be reduced substantially in 2050 if the technological improvements considered in the B1 ACARE will be achieved.

    Shipping emissions have the largest impact in the marine boundary layer and their ozone contribution may exceed 4 ppb (scaled to 100 % over the North Atlantic Ocean in the future (2050; B1 during northern summer (July. In the zonal mean, ship-induced ozone relative to the background levels may exceed 12 % near the surface. Corresponding numbers for OH are 6.0 × 105 molecules cm−3 and 30 %, respectively. This large impact on OH from shipping leads to a relative methane lifetime reduction of 3.92(±0.48 % on the global average in 2050 B1 (ensemble mean CH4 lifetime is 8.0(±1.0 yr, compared to 3.68(±0.47 % in 2000.

    Aircraft emissions have about 4 times higher ozone enhancement efficiency (ozone molecules enhanced relative to NOx molecules emitted than shipping emissions, and the maximum impact is found in the UTLS region. Zonal mean aircraft-induced ozone could reach up to 5 ppb at northern mid- and high latitudes during future summer (July 2050; B1, while the relative impact peaks during

  14. Peppermint antioxidants revisited.

    Science.gov (United States)

    Riachi, Liza G; De Maria, Carlos A B

    2015-06-01

    This review discusses the relationship between the chemical composition and antioxidant property of peppermint tisane and essential oil. Phenolic acids (e.g. rosmarinic and caffeic acids), flavones (e.g. luteolin derivatives) and flavanones (e.g. eriocitrin derivatives) are possibly the major infusion antioxidants. Vitamin antioxidants (e.g. ascorbic acid and carotenoids) are minor contributors to the overall antioxidant potential. Unsaturated terpenes having a cyclohexadiene structure (e.g. terpinene) and minor cyclic oxygenated terpenes (e.g. thymol), may contribute to antioxidant potential whilst acyclic unsaturated oxygenated monoterpenes (e.g. linalool) may act as pro-oxidants in essential oil. Findings on the antioxidant potential of major cyclic oxygenated terpenes (menthol and menthone) are conflicting. Antioxidant behaviour of aqueous/organic solvent extracts and essential oil as well as the effect of environmental stresses on essential oil and phenolic composition are briefly discussed. PMID:25624208

  15. Antioxidants in liver health

    Institute of Scientific and Technical Information of China (English)

    Sael; Casas-Grajales; Pablo; Muriel

    2015-01-01

    Liver diseases are a worldwide medical problem because the liver is the principal detoxifying organ and maintains metabolic homeostasis. The liver metabolizes various compounds that produce free radicals(FR).However, antioxidants scavenge FR and maintain the oxidative/antioxidative balance in the liver. When the liver oxidative/antioxidative balance is disrupted, the state is termed oxidative stress. Oxidative stress leadsto deleterious processes in the liver and produces liver diseases. Therefore, restoring antioxidants is essential to maintain homeostasis. One method of restoring antioxidants is to consume natural compounds with antioxidant capacity. The objective of this review is to provide information pertaining to various antioxidants found in food that have demonstrated utility in improving liver diseases.

  16. Antioxidant activities from different rosemary clonal lines.

    Science.gov (United States)

    Ban, Lan; Narasimhamoorthy, Brindha; Zhao, Liuqing; Greaves, John A; Schroeder, William D

    2016-06-15

    Rosemary extract is widely used in food industry and carnosic acid is reported to be the major component that is responsible for its antioxidant activities. However, it is unclear how the numerous plant metabolites interact and contribute to the overall antioxidant activity. In this study, with poultry fat as the model food system, rosemary extract from six clonal lines were evaluated that each represented a different genetic variant. As expected, rosemary extract with higher carnosic acid content had higher antioxidant activity. However, rosemary extract which had carnosic acid removed retained a significant amount of activity. Furthermore, when the individual contributions of carnosic acid and the portion without carnosic acid were evaluated separately, neither was shown to be responsible for the overall level of its stabilization effect from rosemary extract as a whole entity. The interactions among different plant metabolites have a major impact on the overall antioxidant capabilities of rosemary extract. PMID:26868574

  17. The use of lichens as bioindicators of atmospheric contamination by natural radionuclides and metals in a region impacted by TENORM

    International Nuclear Information System (INIS)

    The main aim of this thesis is to study the possibility of using lichen as bioindicator of atmospheric pollution in regions contaminated by radionuclides, metals and rare earth elements. Two regions were chosen, one in Pirapora do Bom Jesus, where a tin and lead industry is located, and a second one in Cubatao, where a phosphate fertilizer industrial complex is located. The two industries chosen are considered as TENORM - Technologically Enhanced Naturally Occurring Radioactive Material, since they can cause a significant increase in the natural radionuclides concentration in the industrial process, and consequently a potential increase in the radiation exposure in products, byproducts and residue. To achieve this aim, the radionuclides 238U, 226Ra, 210Pb, 2'32Th and 228Ra, rare earth elements and metals were analyzed in samples of raw material and residues from the installations, lichens and soils. Lichens and soil samples were analyzed by instrumental neutron activation analysis for the determination of uranium, thorium, rare earth elements and metals. The radionuclides 226Ra, 228Ra and 2'10Pb in soil samples were determined by gamma spectrometry and in lichen sample by radiochemical separation and gross alpha and beta counting on a gas flow proportional counter. The concentrations of 238U (from 19 to 473 Bq kg-1), 226Ra (from 21 to 265 Bq kg-1), 210Pb (from 401 to 1461 Bq kg-1), 232Th (from 15 to 574 Bq kg-1), 228Ra (from 176 to 535 Bq kg'-1), rare earth elements, Hf and Ta determined in lichen samples around the tin and lead industry show an enrichment in these elements. Therefore, the lichens can be used as a fingerprint of the atmospheric contamination. The results obtained for the lichen samples, in the Cubatao region, present a fingerprint mainly of 210Pb, from industries of the region. The results obtained in this study showed that the lichens can be used as bioindicators of atmospheric pollution by radionuclides and trace elements. (author)

  18. Impacts of increased atmospheric CO2 concentration on photosynthesis and growth of micro-and macro-algae

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Marine photosynthesis drives the oceanic biological CO2 pump to absorb CO2 from the atmosphere, which sinks more than one third of the industry-originated CO2 into the ocean. The increasing atmos-pheric CO2 and subsequent rise of pCO2 in seawater, which alters the carbonate system and related chemical reactions and results in lower pH and higher HCO3- concentration, affect photosynthetic CO2 fixation processes of phytoplanktonic and macroalgal species in direct and/or indirect ways. Although many unicellular and multicellular species can operate CO2-concentrating mechanisms (CCMs) to util-ize the large HCO3- pool in seawater, enriched CO2 up to several times the present atmospheric level has been shown to enhance photosynthesis and growth of both phytoplanktonic and macro-species that have less capacity of CCMs. Even for species that operate active CCMs and those whose photo-synthesis is not limited by CO2 in seawater, increased CO2 levels can down-regulate their CCMs and therefore enhance their growth under light-limiting conditions (at higher CO2 levels, less light energy is required to drive CCM). Altered physiological performances under high-CO2 conditions may cause genetic alteration in view of adaptation over long time scale. Marine algae may adapt to a high CO2 oceanic environment so that the evolved communities in future are likely to be genetically different from the contemporary communities. However, most of the previous studies have been carried out under indoor conditions without considering the acidifying effects on seawater by increased CO2 and other interacting environmental factors, and little has been documented so far to explain how physi-ology of marine primary producers performs in a high-CO2 and low-pH ocean.

  19. Impacts of increased atmospheric CO2 concentration on photosynthesis and growth of micro- and macro-algae

    Institute of Scientific and Technical Information of China (English)

    WU HongYan; ZOU DingHui; GAO KunShan

    2008-01-01

    Marine photosynthesis drives the oceanic biological CO2 pump to absorb CO2 from the atmosphere, which sinks more than one third of the industry-originated CO2 into the ocean. The increasing atmospheric CO2 and subsequent rise of pCO2 in seawater, which alters the carbonate system and related chemical reactions and results in lower pH and higher HCO3- concentration, affect photosynthetic CO2 fixation processes of phytoplanktonic and macroalgal species in direct and/or indirect ways. Although many unicellular and multicellular species can operate CO2-concentrating mechanisms (CCMs) to utilize the large HCO3- pool in seawater, enriched CO2 up to several times the present atmospheric level has been shown to enhance photosynthesis and growth of both phytoplanktonic and macro-species that have less capacity of CCMs. Even for species that operate active CCMs and those whose photosynthesis is not limited by CO2 in seawater, increased CO2 levels can down-regulate their CCMs and therefore enhance their growth under light-limiting conditions (at higher CO2 levels, less light energy is required to drive CCM). Altered physiological performances under high-CO2 conditions may cause genetic alteration in view of adaptation over long time scale. Marine algae may adapt to a high CO2 oceanic environment so that the evolved communities in future are likely to be genetically different from the contemporary communities. However, most of the previous studies have been carried out under indoor conditions without considering the acidifying effects on seawater by increased CO2 and other interacting environmental factors, and little has been documented so far to explain how physiology of marine primary producers performs in a high-CO2 and low-pH ocean.

  20. Impact of vegetation on land-atmosphere coupling strength and its implication for desertification mitigation over East Asia

    Science.gov (United States)

    Myoung, Boksoon; Choi, Yong-Sang; Choi, Suk-Jin; Park, Seon Ki

    2012-06-01

    Desertification of the East Asian drylands and the consequent dust transport have been serious concerns for adjacent Asian countries as well as the western United States. Tree planting has been considered one applicable strategy to mitigate the desertification. However, the desired effect of the tree planting would not be brought to fruition unless the newly planted trees change the coupling characteristics between the land and the atmosphere. Based on this perception, we attempt to clarify the effects of vegetation on the coupling strength between the atmosphere and land surface, and we suggest the most efficient areas of tree planting for desertification mitigation in East Asia. Using regional vegetation-atmosphere coupled model simulations, coupling strength with and without vegetation was computed and compared with each other. An increased vegetation fraction reduces the coupling strength in June, July, and August (JJA), primarily due to decreased evapotranspiration variability. This effect is pronounced over the Manchurian Plains and the highly populated areas of Beijing and Tianjin. The reduced coupling strength tends to weaken feedback between soil moisture and precipitation as a maintenance mechanism of warm season droughts in the midlatitudes and subsequently decrease the probability of droughts, a finding that is reflected in the enhanced JJA mean soil moisture. However, some drylands like the eastern edges of the Gobi desert present marginal or even opposite changes in coupling strength, meaning a limited effect of vegetation on relieving droughts. Therefore, given limited financial and human resources, acupuncture-like afforestation, i.e., concentrated tree planting in a particular region where the coupling strength can be substantially reduced by vegetation, is an effective strategy to secure long-standing desertification mitigation.

  1. Impact of the O2 concentrations on bacterial communities and quality of modified atmosphere packaged Pacific white shrimp (Litopenaeus vannamei).

    Science.gov (United States)

    Qian, Yun-Fang; Yang, Sheng-Ping; Xie, Jing; Xiong, Qing; Gao, Zhi-Li

    2013-12-01

    The importance of spoilage-related bacteria in fresh Pacific white shrimp (Litopenaeus vannamei) under different modified atmospheres (MAs) at 4 °C and the effect of O2 were demonstrated in the current study. The changes of bacterial communities in MA-packed shrimp during cold storage were studied by a combined method of plate counts with isolation and identification. Three gas mixtures were applied: 80% CO2 /5% O2 /15% N2, 80% CO2 /10% O2 /10% N2 and 80% CO2 /20% O2, and unsealed packages of shrimp were used as the control. In addition, the TVB-N, pH, whiteness index, and sensory scores were also determined to evaluate the quality changes of shrimp. MA packaging effectively inhibited the increase of total psychrotrophic bacteria counts and H2 S-producing bacteria counts by about 1.7 and 2.1 log cycles, respectively. The growth of Gram-negative spoilage bacteria in shrimp, including Shewanella spp., Aeromonas spp., and Pseudomonas spp., was inhibited by MA packaging, but the growth rate of Gram-positive bacteria such as lactic acid bacteria (LAB) and Brochothrix spp. were less affected by MA as effectively as Gram-negative bacteria. In comparison with the MA-packaged samples, the counts of H2 S producers in shrimp under a CO2 -enriched atmosphere with 20% O2 were slightly lower than the count in samples under an atmosphere with 5% O2 . However, MA with 20% O2 led to higher concentrations of TVB-N, and lower whiteness values and sensory scores. The shelf life of shrimp under 80% CO2 /10% O2 /10% N2 has been prolonged by > 6 d in comparison with the control according to the sensory scores.

  2. [Efficacy of disinfection treatments using essential oils and ultrasound on tomato fruits inoculated with Escherichia coli and impact on antioxidant activity].

    Science.gov (United States)

    Luna Guevara, María L; Luna Guevara, Juan J; Ruiz Espinosa, Héctor; Leyva Abascal, Lucero; Díaz González, Carolina B

    2015-01-01

    Fresh produce often harbors a great number of microorganisms; hence, its growing demand may constitute a risk for consumers. The aim of this study was to evaluate the efficacy of several disinfection procedures against enterotoxigenic Escherichia coli (ETEC) inoculated on tomato fruits and the conservation of the antioxidant properties of these disinfected fruits. Fruits were immersed for 5 or 10min in oregano or thyme essential oil dispersions (5, 10ppm), with or without ultrasound treatment. Antioxidant activity of disinfected fruits was determined as the ability to scavenge 2,2-diphenyl-1-pricrylhydrazyl (DPPH) radicals and was reported as percentage of inhibition (%I). The most efficient disinfectant treatments showing significant differences (p≤.05) between the reductions log10 CFU/g (S) of ETEC were those using 10ppm oregano for 10min, with S=3.05 in individual treatments and S=4.03 in mixed treatments. The highest %I was obtained with individual sonication treatments (69.52 and 72.48), while in combined treatments the %I values increased with thyme oil 5ppm and ultrasound for 5min (51.27%) and 10min (53.31%).

  3. Atmospheric dry deposition of inorganic and organic nitrogen to the Bay of Bengal: Impact of continental outflow

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

    in the deep freezer at - 19 0 C until the time of analysis. The mass concentrations of PM 2.5 and PM 10 were obtained gravimetrically by measuring the weight of the filters, before and after the collection. All samples were handled under a clean laminar-flow..., including organic nitrogen (N Org ), are bio-available (Bronk et al., 2007; Duce et al., 2008; Jickells, 2006; Seitzinger and Sanders, 1999; Spokes et al., 2000). As a result, studies on atmospheric deposition needs to be extended to measure organic...

  4. Resistive switching of Ti/HfO2-based memory devices: impact of the atmosphere and the oxygen partial pressure

    International Nuclear Information System (INIS)

    The electrical characteristics of different resistance states (virgin, OFF and ON) of a Ti/HfO2/TiN metal-insulator-metal device for resistance random access memory are investigated under different gas ambient. The influence of the atmosphere, the total pressure and the oxygen concentration during electrical measurements is underlined thanks to retention (I-t) and impedance spectroscopy (Z-f) measurements. The total pressure influences the current levels of the three different resistive states: when the total pressure decreases, the current increases, probably due to an increase of the concentration of oxygen vacancies in the HfO2.

  5. Resistive switching of Ti/HfO2-based memory devices: impact of the atmosphere and the oxygen partial pressure

    Science.gov (United States)

    Bertaud, T.; Sowinska, M.; Walczyk, D.; Walczyk, Ch; Kubotsch, S.; Wenger, Ch; Schroeder, T.

    2012-12-01

    The electrical characteristics of different resistance states (virgin, OFF and ON) of a Ti/HfO2/TiN metal-insulator-metal device for resistance random access memory are investigated under different gas ambient. The influence of the atmosphere, the total pressure and the oxygen concentration during electrical measurements is underlined thanks to retention (I-t) and impedance spectroscopy (Z-f) measurements. The total pressure influences the current levels of the three different resistive states: when the total pressure decreases, the current increases, probably due to an increase of the concentration of oxygen vacancies in the HfO2.

  6. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, M., E-mail: karl-ernst.wirth@fau.de; Schmitt, A., E-mail: karl-ernst.wirth@fau.de; Schmidt, J., E-mail: karl-ernst.wirth@fau.de; Peukert, W., E-mail: karl-ernst.wirth@fau.de; Wirth, K-E, E-mail: karl-ernst.wirth@fau.de [Institute of Particle Technology, University of Erlangen-Nuremberg (Germany)

    2014-05-15

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  7. Impacts of changes in land use and land cover on atmospheric chemistry and air quality over the 21st century

    Directory of Open Access Journals (Sweden)

    S. Wu

    2011-05-01

    Full Text Available The effects of future land use and land cover change on the chemical composition of the atmosphere and air quality are largely unknown. To investigate the potential effects associated with future changes in vegetation driven by atmospheric CO2 concentrations, climate, and anthropogenic land use over the 21st century, we performed a series of model experiments combining a general circulation model with a dynamic global vegetation model and an atmospheric chemical-transport model. Our results indicate that climate- and CO2-induced changes in vegetation composition and density could lead to decreases in summer afternoon surface ozone of up to 10 ppb over large areas of the northern mid-latitudes. This is largely driven by the substantial increases in ozone dry deposition associated with changes in the composition of temperate and boreal forests where conifer forests are replaced by those dominated by broadleaf tree types, as well as a CO2-driven increase in vegetation density. Climate-driven vegetation changes over the period 2000–2100 lead to general increases in isoprene emissions, globally by 15 % in 2050 and 36 % in 2100. These increases in isoprene emissions result in decreases in surface ozone concentrations where the NOx levels are low, such as in remote tropical rainforests. However, over polluted regions, such as the northeastern United States, ozone concentrations are calculated to increase with higher isoprene emissions in the future. Increases in biogenic emissions also lead to higher concentrations of secondary organic aerosols, which increase globally by 10 % in 2050 and 20 % in 2100. Surface concentrations of secondary organic aerosols are calculated to increase by up to 1 μg m−3 for large areas in Eurasia. When we use a scenario of future anthropogenic land use change, we find less increase in global isoprene emissions due to replacement of higher-emitting forests by lower

  8. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    Science.gov (United States)

    Sachs, M.; Schmitt, A.; Schmidt, J.; Peukert, W.; Wirth, K.-E.

    2014-05-01

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  9. Update on Atmospheric Neutrinos

    CERN Document Server

    González-Garciá, M Concepción; Peres, O L G; Stanev, T; Valle, José W F

    1998-01-01

    We discuss the impact of recent experimental results on the determination of atmospheric neutrino oscillation parameters. We use all published results on atmospheric neutrinos, including the preliminary large statistics data of Super-Kamiokande. We re-analyze the data in terms of both $\

  10. The impact of the atmospheric model and of the space weather data on the dynamics of clouds of space debris

    Science.gov (United States)

    Petit, Alexis; Lemaitre, Anne

    2016-06-01

    New tools are necessary to deal with more than hundred thousands of space debris, thus our aim is to develop software able to propagate numerous trajectories and manage collisions or fragmentations. Specifically in low orbits Earth, gravity and atmospheric drag are the two main forces that affect the dynamics of the artificial satellites or space debris. NIMASTEP, the local orbit propagator, initially designed for high altitudes, has been adapted to low altitude orbits. To study the future debris environment, we propose a suitable model of space weather and we compare three different atmospheric density models (Jacchia-Bowman 2008, DTM-2013, and TD-88) able to propagate with accuracy and efficiency a large population of space debris on long time scales. We compare the results in different altitudes and during the reentry regime; we show, with a ballistic coefficient constant, a trend to underestimate or overestimate the decrease of the semi-major axis, specifically during the periods of high solar activity. We parallelize our software and use the calculation power of a computing cluster, we propagate a huge cloud of debris and we show that its global evolution is in agreement with the observations on several years.

  11. Impacts from ice-nucleating bacteria on deep convection: implications for the biosphere-atmosphere interaction in climate change

    Directory of Open Access Journals (Sweden)

    V. T. J. Phillips

    2008-03-01

    Full Text Available A cloud modeling framework is described to simulate ice nucleation by biogenic aerosol particles, as represented by airborne ice-nucleation active (INA bacteria. It includes the empirical parameterization of heterogeneous ice nucleation. The formation of cloud liquid by soluble material coated on such insoluble aerosols is represented and determines their partial removal from deep convective clouds by accretion onto precipitation.

    Preliminary simulations are performed for a case of deep convection over Oklahoma. If present at high enough concentrations, as might occur in proximity to land sources, INA bacteria are found to influence significantly: – (1 the average numbers and sizes of crystals in the clouds; (2 the horizontal cloud coverage in the free troposphere; and (3 precipitation and incident solar insolation at the surface, which influence rates of bacterial growth. At lower concentrations, the corresponding responses of cloud fields appear much lower or are ambiguous.

    In nature, the growth rates of INA bacteria on leaves prior to emission into the atmosphere are known to be highly dependent on temperature, precipitation and plant species. Consequently, the open question emerges of whether emissions of such ice-nucleating biogenic particles can then be modified by their own effects on clouds and atmospheric conditions, forming a weak feedback in climate or microclimate systems.

  12. Changes in atmospheric variability in a glacial climate and the impacts on proxy data: a model intercomparison

    Directory of Open Access Journals (Sweden)

    F. S. R. Pausata

    2009-09-01

    Full Text Available Using four different climate models, we investigate sea level pressure variability in the extratropical North Atlantic in the preindustrial climate (1750 AD and at the Last Glacial Maximum (LGM, 21 kyrs before present in order to understand how changes in atmospheric circulation can affect signals recorded in climate proxies.

    In general, the models exhibit a significant reduction in interannual variance of sea level pressure at the LGM compared to pre-industrial simulations and this reduction is concentrated in winter. For the preindustrial climate, all models feature a similar leading mode of sea level pressure variability that resembles the leading mode of variability in the instrumental record: the North Atlantic Oscillation (NAO. In contrast, the leading mode of sea level pressure variability at the LGM is model dependent, but in each model different from that in the preindustrial climate. In each model, the leading (NAO-like mode of variability explains a smaller fraction of the variance and also less absolute variance at the LGM than in the preindustrial climate.

    The models show that the relationship between atmospheric variability and surface climate (temperature and precipitation variability change in different climates. Results are model-specific, but indicate that proxy signals at the LGM may be misinterpreted if changes in the spatial pattern and seasonality of surface climate variability are not taken into account.

  13. Impact of atmospheric CO2 on growth, photosynthesis and nitrogen metabolism in cucumber (Cucumis sativus L.) plants.

    Science.gov (United States)

    Agüera, Eloísa; Ruano, David; Cabello, Purificación; de la Haba, Purificación

    2006-07-01

    Expression and activity of nitrate reductase (NR; EC 1.6.6.1) and glutamine synthetase (GS; EC 6.3.1.2) were analysed in relation to the rate of CO(2) assimilation in cucumber (Cucumis sativus L.) leaves. Intact plants were exposed to different atmospheric CO(2) concentrations (100, 400 and 1200microLL(-1)) for 14 days. A correlation between the in vivo rates of net CO(2) assimilation and the atmospheric CO(2) concentrations was observed. Transpiration rate and stomatal conductance remained unaffected by CO(2) levels. The exposure of the cucumber plants to rising CO(2) concentrations led to a concomitant increase in the contents of starch and soluble sugars, and a decrease in the nitrate content in leaves. At very low CO(2), NR and GS expression decreased, in spite of high nitrate contents, whereas at normal and elevated CO(2) expression and activity were high although the nitrate content was very low. Thus, in cucumber, NR and GS expression appear to be dominated by sugar levels, rather than by nitrate contents.

  14. Composition and properties of atmospheric particles in the eastern Atlantic and impacts on gas phase uptake rates

    Directory of Open Access Journals (Sweden)

    G. McFiggans

    2009-12-01

    Full Text Available Marine aerosol composition continues to represent a large source of uncertainty in the study of climate and atmospheric chemistry. In addition to their physical size and chemical composition, hygroscopicity plays a significant role, increasing the particles' surface areas and scattering potential. Simultaneous aerosol measurements were performed on board the RRS Discovery and at the Cape Verde atmospheric observatory during the Aerosol Composition and Modelling in the Marine Environment (ACMME and Reactive Halogens in the Marine Boundary Layer (RHAMBLE experiments. These included online measurements of number and dry size and bulk collection for offline analysis of aqueous ions. In addition, the measurements on board the Discovery included online measurements of composition using an Aerodyne Aerosol Mass Spectrometer, optical absorption using a Multi Angle Absorption Photometer, ambient humidity size distribution measurements using a humidified differential mobility particle sizer (DMPS and optical particle counter (OPC and hygroscopicity measurements with a hygroscopicity tandem differential mobility analyser (HTDMA.

    Good agreement between platforms in terms of the sea salt (ss and non sea salt (nss modes was found during the period when the Discovery was in close proximity to Cape Verde and showed a composition consistent with remote marine air. As the Discovery approached the African coast, the aerosol showed signs of continental influence such as an increase in particle number, optical absorption, enhancement of the nss mode and dust particles. The Cape Verde site was free of this influence during this period. Chloride and bromide showed concentrations with significant deviations from seawater relative to sodium, indicating that atmospheric halogen processing (and/or acid displacement for chloride had taken place. The time dependent ambient size distribution was synthesised using humidified DMPS and OPC data, corrected to ambient

  15. Impact of innovative controlled atmosphere storage technologies and postharvest treatments on volatile compound production in cv. Pinova apples.

    Science.gov (United States)

    Raffo, Antonio; Kelderer, Markus; Paoletti, Flavio; Zanella, Angelo

    2009-02-11

    Organically grown apples cv. Pinova harvested at two different dates were stored at 1.3 degrees C for up to 4 months in air, up to 7 months in ULO (1.5 kPa of O(2) and 1.3 kPa of CO(2)) and in dynamic controlled atmosphere (DCA) conditions (0.4-0.6 kPa of O(2) and 0.6-0.8 kPa of CO(2)); the DCA storage method involved the use of a chlorophyll fluorescence monitoring system in order to detect low-O(2) stress in apples and to allow for the dynamic adaptation of storage atmosphere to O(2) levels that were lower than in ULO but still tolerated by fruits. A postharvest 1-MCP treatment (for 24 h at 1.3 degrees C) and a hot water treatment (for 180 s at 50 degrees C) were also tested on apples stored afterward in ULO and air, respectively. Volatile compounds isolated from the pulp of fruits were measured after 4 and 7 months, just upon removal from storage and after 11 days at 22 degrees C. Total amount of aroma compounds detected in apples stored in DCA was markedly higher (from 2- to 4-fold) than in fruits exposed to 1-MCP + ULO but, at most sampling times, significantly lower than in ULO fruits. Moderate differences in storage atmosphere composition between ULO and DCA significantly affected both total amount and profile of volatile esters. Analogous effects were observed on the alcohol precursors of the main esters. Exposure to 1-MCP inhibited biosynthesis of straight-chain esters more than that of branched-chain esters. The hot water treatment did not seem to produce marked changes in volatile composition after four months of air storage, except for a sharp accumulation of aldehydes during the shelf-life time. DCA storage technology, besides avoiding any chemical treatment, can preserve apple aroma compounds better than 1-MCP + ULO during long-term storage.

  16. Impact of temperature field inhomogeneities on the retrieval of atmospheric species from MIPAS IR limb emission spectra

    Directory of Open Access Journals (Sweden)

    M. Kiefer

    2010-04-01

    Full Text Available We examine volume mixing ratios (vmr retrieved from limb emission spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. In level 2 (L2 data products of three different retrieval processors, which perform one dimensional (1-D retrievals, we find significant differences between species' profiles from ascending and descending orbit parts. The relative differences vary systematically with time of the year, latitude, and altitude. In the lower stratosphere their monthly means can reach maxima of 20% for CFC-11, CFC-12, HNO3, H2O, 10% for CH4 and N2O. Relative differences between monthly means of 1-D retrieval results and of the true atmospheric state can be expected to reach half of these percentage values, while relative differences in single vmr profiles might well exceed those numbers. Often there are no physical or chemical reasons for these differences, so they are an indicator for a problem in the data processing. The differences are generally largest at locations where the meridional temperature gradient of the atmosphere is strong. On the contrary, when performing the retrieval with a tomographic two dimensional (2-D retrieval, L2 products generally do not show these differences. This implies that inhomogeneities in the temperature field, and possibly in the species' fields, which are accounted for in the 2-D algorithm and not in standard 1-D processors, may cause significant deviations in the results. Inclusion of an externally given adequate temperature gradient in the forward model of a 1-D processor helps to reduce the observed differences. However, only the full tomographic approach is suitable to resolve the horizontal inhomogeneities. Implications for the use of the 1-D data, e.g. for validation, are discussed. The dependence of the ascending/descending differences on the observation strategy suggests that this problem is to be expected to affect in

  17. The present-day and future impact of NOx emissions from subsonic aircraft on the atmosphere in relation to the impact of NOx surface sources

    Directory of Open Access Journals (Sweden)

    G. J. M. Velders

    Full Text Available The effect of present-day and future NOx emissions from aircraft on the NOx and ozone concentrations in the atmosphere and the corresponding radiative forcing were studied using a three-dimensional chemistry transport model (CTM and a radiative model. The effects of the aircraft emissions were compared with the effects of the three most important anthropogenic NOx surface sources: road traffic, electricity generation and industrial combustion. From the model results, NOx emissions from aircraft are seen to cause an increase in the NOx and ozone concentrations in the upper troposphere and lower stratosphere, and a positive radiative forcing. For the reference year 1990, the aircraft emissions result in an increase in the NOx concentration at 250 hPa of about 20 ppt in January and 50 ppt in July over the eastern USA, the North Atlantic Flight Corridor and Western Europe, corresponding to a relative increase of about 50%. The maximum increase in the ozone concentrations due to the aircraft emissions is about 3-4 ppb in July over the northern mid-latitudes, corresponding to a relative increase of about 3-4%. The aircraft-induced ozone changes cause a global average radiative forcing of 0.025 W/m2 in July. According to the ANCAT projection for the year 2015, the aircraft NOx emissions in that year will be 90% higher than in the year 1990. As a consequence of this, the calculated NOx perturbation by aircraft emissions increases by about 90% between 1990 and 2015, and the ozone perturbation by about 50-70%. The global average radiative forcing due to the aircraft-induced ozone changes increases by about 50% between 1990 and 2015. In the year 2015, the effects of the aircraft emissions on the ozone burden and radiative forcing are clearly larger than the individual effects of the NOx surface sources. Taking chemical conversion in the aircraft plume into account in the CTM explicitly, by means of modified aircraft NOx emissions, a significant reduction

  18. Seasonal dynamics of coarse atmospheric particulate matter between 2.5 μm and 80 μm in Beijing and the impact of 2008 Olympic Games

    Science.gov (United States)

    Norra, Stefan; Yu, Yang; Dietze, Volker; Schleicher, Nina; Fricker, Mathieu; Kaminski, Uwe; Chen, Yuan; Stüben, Doris; Cen, Kuang

    2016-01-01

    Beijing is well known as a megacity facing severe atmospheric pollution problems. One very important kind of pollution is the high amount of particles in Beijing's atmosphere. Numerous studies investigated the dynamics of fine particles smaller 10 μm. Less information is available on the coarse particle fraction larger 10 μm, although geogenic dusts, which often are composed by those coarser particles, frequently affect the air quality in Beijing. Therefore, systematic sampling and analysis of size fractionated particulate matter between 2.5 and 80 μm was performed in Beijing from April 2005 till October 2009. Atmospheric particles were collected in the North-West of Beijing using a cost-effective passive sampling method called Sigma-2. Altogether, 200 weeks could be analysed and assessed. Concentrations and size distribution of atmospheric coarse particles were determined by automated microscopic single particle analysis. Seasonal variability of the total mass of different size fractions was identified as follows: spring > winter > autumn > summer. High concentrations of transparent mineral particles indicate the activity of geogenic sources in spring and winter time, due to asian dust events and resuspension of soil from local bare land during dry and windy periods. The percentage of opaque particle components differs seasonally with relatively high values in winter, confirming combustion of fossil fuels for heating purposes as a predominant pollution source in this season. The influence of meteorological conditions on concentrations and size distribution of atmospheric particulate matter between 2.5 and 80 μm is demonstrated for the whole sampling period. Lowest pollution by coarse aerosols occurred during the period of the 2008 Olympic Summer Games. A general trend of decreasing total coarse particle mass concentrations was observed. Due to frequently observed high total coarse particle mass concentrations of several 100 μg·m-³ it is strongly recommended

  19. Both water source and atmospheric water impact leaf wax n-alkane 2H/1H values of hydroponically grown angiosperm trees

    Science.gov (United States)

    Tipple, B. J.; Berke, M. A.; Hambach, B.; Roden, J. S.; Ehleringer, J. R.

    2013-12-01

    atmospheric conditions significantly impacted the δ2H value of leaf wax n-alkanes. From this, we concluded both source water and humidity information was recorded in leaf wax lipids δ2H values of broad-leaved angiosperm species at the time of leaf wax synthesis.

  20. Causes of change in nitrophytic and oligotrophic lichen species in a Mediterranean climate: Impact of land cover and atmospheric pollutants

    International Nuclear Information System (INIS)

    With the aim of determining the main drivers of changes in nitrophytic and oligotrophic macro-lichen communities in an industrial region with a Mediterranean climate, we considered both land-cover types and atmospheric pollutants. We determined the relation between the abundance of nitrophytic and oligotrophic species with environmental fac