WorldWideScience

Sample records for sea salt aerosols

  1. An Investigation of the Radiative Effects and Climate Feedbacks of Sea Ice Sources of Sea Salt Aerosol

    Science.gov (United States)

    Horowitz, H. M.; Alexander, B.; Bitz, C. M.; Jaegle, L.; Burrows, S. M.

    2017-12-01

    In polar regions, sea ice is a major source of sea salt aerosol through lofting of saline frost flowers or blowing saline snow from the sea ice surface. Under continued climate warming, an ice-free Arctic in summer with only first-year, more saline sea ice in winter is likely. Previous work has focused on climate impacts in summer from increasing open ocean sea salt aerosol emissions following complete sea ice loss in the Arctic, with conflicting results suggesting no net radiative effect or a negative climate feedback resulting from a strong first aerosol indirect effect. However, the radiative forcing from changes to the sea ice sources of sea salt aerosol in a future, warmer climate has not previously been explored. Understanding how sea ice loss affects the Arctic climate system requires investigating both open-ocean and sea ice sources of sea-salt aerosol and their potential interactions. Here, we implement a blowing snow source of sea salt aerosol into the Community Earth System Model (CESM) dynamically coupled to the latest version of the Los Alamos sea ice model (CICE5). Snow salinity is a key parameter affecting blowing snow sea salt emissions and previous work has assumed constant regional snow salinity over sea ice. We develop a parameterization for dynamic snow salinity in the sea ice model and examine how its spatial and temporal variability impacts the production of sea salt from blowing snow. We evaluate and constrain the snow salinity parameterization using available observations. Present-day coupled CESM-CICE5 simulations of sea salt aerosol concentrations including sea ice sources are evaluated against in situ and satellite (CALIOP) observations in polar regions. We then quantify the present-day radiative forcing from the addition of blowing snow sea salt aerosol with respect to aerosol-radiation and aerosol-cloud interactions. The relative contributions of sea ice vs. open ocean sources of sea salt aerosol to radiative forcing in polar regions is

  2. Frost flowers and sea-salt aerosols over seasonal sea-ice areas in northwestern Greenland during winter–spring

    Directory of Open Access Journals (Sweden)

    K. Hara

    2017-07-01

    Full Text Available Sea salts and halogens in aerosols, frost flowers, and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in northwestern Greenland during December 2013 to March 2014. Results show that water-soluble frost flower and brine components are sea-salt components (e.g., Na+, Cl−, Mg2+, K+, Ca2+, Br−, and iodine. Concentration factors of sea-salt components of frost flowers and brine relative to seawater were 1.14–3.67. Sea-salt enrichment of Mg2+, K+, Ca2+, and halogens (Cl−, Br−, and iodine in frost flowers is associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. High aerosol number concentrations correspond to the occurrence of higher abundance of sea-salt particles in both coarse and fine modes, and blowing snow and strong winds. Aerosol number concentrations, particularly in coarse mode, are increased considerably by release from the sea-ice surface under strong wind conditions. Sulfate depletion by sea-salt fractionation was found to be limited in sea-salt aerosols because of the presence of non-sea-salt (NSS SO42−. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Magnesium-rich sea-salt particles might be released from the surface of snow and slush layer (brine on sea ice and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas. From the field evidence and results from earlier studies, we propose and describe sea-salt cycles in seasonal sea-ice areas.

  3. Frost flowers and sea-salt aerosols over seasonal sea-ice areas in northwestern Greenland during winter-spring

    Science.gov (United States)

    Hara, Keiichiro; Matoba, Sumito; Hirabayashi, Motohiro; Yamasaki, Tetsuhide

    2017-07-01

    Sea salts and halogens in aerosols, frost flowers, and brine play an important role in atmospheric chemistry in polar regions. Simultaneous sampling and observations of frost flowers, brine, and aerosol particles were conducted around Siorapaluk in northwestern Greenland during December 2013 to March 2014. Results show that water-soluble frost flower and brine components are sea-salt components (e.g., Na+, Cl-, Mg2+, K+, Ca2+, Br-, and iodine). Concentration factors of sea-salt components of frost flowers and brine relative to seawater were 1.14-3.67. Sea-salt enrichment of Mg2+, K+, Ca2+, and halogens (Cl-, Br-, and iodine) in frost flowers is associated with sea-salt fractionation by precipitation of mirabilite and hydrohalite. High aerosol number concentrations correspond to the occurrence of higher abundance of sea-salt particles in both coarse and fine modes, and blowing snow and strong winds. Aerosol number concentrations, particularly in coarse mode, are increased considerably by release from the sea-ice surface under strong wind conditions. Sulfate depletion by sea-salt fractionation was found to be limited in sea-salt aerosols because of the presence of non-sea-salt (NSS) SO42-. However, coarse and fine sea-salt particles were found to be rich in Mg. Strong Mg enrichment might be more likely to proceed in fine sea-salt particles. Magnesium-rich sea-salt particles might be released from the surface of snow and slush layer (brine) on sea ice and frost flowers. Mirabilite-like and ikaite-like particles were identified only in aerosol samples collected near new sea-ice areas. From the field evidence and results from earlier studies, we propose and describe sea-salt cycles in seasonal sea-ice areas.

  4. Sea salt in aerosols over the southern Baltic. Part 2. The neutralizing properties of sea salt and ammonia

    Directory of Open Access Journals (Sweden)

    Anita Urszula Lewandowska

    2013-05-01

    Full Text Available In 2001-2007 aerosols were measured in the coastal zone (11 campaigns and over the open waters of the Gdańsk Basin (southern Baltic (5 campaigns. The marine aerosols contained nitrogen and sulphur compounds, which increased their acidity. This situation intensified during the cool months of the year, when fossil fuel emissions were higher, proportionate to energy and heat requirements. Irrespective of the season, these acidic aerosols were neutralized in the reaction with sea salt. The likelihood of sodium nitrate being formed increased at air humidities > 80% and nitrate concentrations > 30 nmol m-3. Sodium sulphate was present in aerosols mostly in autumn and winter, with northerly advection, and at the highest wind speeds. The excess of free ammonia resulted in the formation of ammonium sulphate and ammonium nitrate in aerosols over the southern Baltic.

  5. Determination of the environmental effect for the sea salt aerosols corrosion (3)

    International Nuclear Information System (INIS)

    Nakayasu, Fumio; Umehara, Toshihiro; Kato, Akitoshi; Taniguchi, Akihide

    2009-01-01

    Fukui Prefecture presently hosts 15 reactor units, including PWRs, BWR, FBR (Monjyu) and Japanese ATR (Fugen), all of which are located along the Japan Sea. Under such a circumstange, corrosion due to sea salt aerosols is one of the major factors causing ageing degradation of nuclear power plants facilities. Many scientists have been engaged in research on the corrosion of structures due to sea salt aerosols. In pursuing sea salt aerosol-induced corrosion research, it was necessary to perform corrosion tests under a certain set of environmental conditions since corrosion of structures is highly sensitive to environmental factors. In this respect, we installed the outdoor exposure test facilities along the sea coast in Awara-city and inland in Fukui-city, Fukui Prefecture of Japan. The amounts of sea salt aerosol tend to be lower in the summer season and higher in the winter season. The difference between seasons is expected to relate to the wind speed, the sunshine time, the rain amount and others. We tried to use the multivariate analysis for finding some relations between sea salt aerosol amounts and environment factor. We found the clear relations. (author)

  6. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Now at Department of Earth System Science, University of California, Irvine California USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Burrows, Susannah M. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-09-23

    In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.

  7. The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic

    Directory of Open Access Journals (Sweden)

    H. Struthers

    2011-04-01

    Full Text Available Understanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent change in radiative balance is examined. A set of idealized climate model simulations were performed to quantify the radiative effects of changes in sea salt aerosol emissions induced by prescribed changes in sea ice extent. The model was forced using sea ice concentrations consistent with present day conditions and projections of sea ice extent for 2100. Sea salt aerosol emissions increase in response to a decrease in sea ice, the model results showing an annual average increase in number emission over the polar cap (70–90° N of 86 × 106 m−2 s−1 (mass emission increase of 23 μg m−2 s−1. This in turn leads to an increase in the natural aerosol optical depth of approximately 23%. In response to changes in aerosol optical depth, the natural component of the aerosol direct forcing over the Arctic polar cap is estimated to be between −0.2 and −0.4 W m−2 for the summer months, which results in a negative feedback on the system. The model predicts that the change in first indirect aerosol effect (cloud albedo effect is approximately a factor of ten greater than the change in direct aerosol forcing although this result is highly uncertain due to the crude representation of Arctic clouds and aerosol-cloud interactions in the model. This study shows that both the natural aerosol direct and first indirect effects are strongly dependent on the surface albedo, highlighting the strong coupling between sea ice, aerosols, Arctic clouds and their radiative effects.

  8. Optical Modeling of Sea Salt Aerosols: The Effects of Nonsphericity and Inhomogeneity

    Science.gov (United States)

    Bi, Lei; Lin, Wushao; Wang, Zheng; Tang, Xiaoyun; Zhang, Xiaoyu; Yi, Bingqi

    2018-01-01

    The nonsphericity and inhomogeneity of marine aerosols (sea salts) have not been addressed in pertinent radiative transfer calculations and remote sensing studies. This study investigates the optical properties of nonspherical and inhomogeneous sea salts using invariant imbedding T-matrix simulations. Dry sea salt aerosols are modeled based on superellipsoidal geometries with a prescribed aspect ratio and roundness parameter. Wet sea salt particles are modeled as coated superellipsoids, as spherical particles with a superellipsoidal core, and as homogeneous spheres depending on the level of relative humidity. Aspect ratio and roundness parameters are found to be critical to interpreting the linear depolarization ratios (LDRs) of NaCl crystals from laboratory measurements. The optimal morphology parameters of NaCl necessary to reproduce the measurements are found to be consistent with data gleaned from an electron micrograph. The LDRs of wet sea salts are computed based on inhomogeneous models and compared with the measured data from ground-based LiDAR. The dependence of the LDR on relative humidity is explicitly considered. The increase in the LDR with relative humidity at the initial phase of deliquescence is attributed to both the size increase and the inhomogeneity effect. For large humidity values, the LDR substantially decreases because the overall particle shape becomes more spherical and the inhomogeneity effect in a particle on the LDR is suppressed for submicron sea salts. However, the effect of inhomogeneity on optical properties is pronounced for coarse-mode sea salts. These findings have important implications for atmospheric radiative transfer and remote sensing involving sea salt aerosols.

  9. Nuclear risk reduction study. The study of structure corrosion caused by sea salt aerosols

    International Nuclear Information System (INIS)

    Nakayasu, Fumio

    2008-01-01

    Present all nuclear power plants in Fukui prefecture are located at the bay side of Japan Sea coast. New facilities may be planed to be at ocean side. The sea salt corrosion at the ocean side should be larger than it at the bay side. We have the salt damage experimental yard at Awara sea coast and at Fukui city (about 15km from coast) for the corrosion comparison study between Japan Sea coast and inland. We confirm the amounts of sea salt aerosol vary among the season and year. The weight loss of specimen inside of shelter without filter is higher than both of sheltered with filter and inland specimen. The weight loss of specimen inside of shelter with filter is almost same as it of inland specimen. We confirmed the filter which we used is sufficient capability to prevent corrosion. We confirmed the corrosion rate of both opened specimen and sheltered specimen without filter increased after some periods. (author)

  10. Determination of the environmental effect for the sea salt aerosols corrosion (2)

    International Nuclear Information System (INIS)

    Nakayasu, Fumio; Umehara, Toshihiro; Kato, Akitoshi; Taniguchi, Akihide

    2008-01-01

    Present all nuclear power plants in Fukui prefecture are located at the bay side of Japan Sea coast. New facilities may be planed to be at ocean side. The sea salt corrosion at the ocean side should be larger than it at the bay side. We have the salt damage experimental yard at Awara sea coast and at Fukui city (about 15km from coast) for the corrosion comparison study between Japan Sea coast and inland. We confirm the amounts of sea salt aerosol vary among the season and year. The weight loss of specimen inside of shelter without filter is higher than both of sheltered with filter and inland specimen. The weight loss of specimen inside of shelter with filter is almost same as it of inland specimen. We confirmed the filter which we used is sufficient capability to prevent corrosion. We confirmed the corrosion rate of both opened specimen and sheltered specimen without filter increased after some periods. (author)

  11. TEM study of soot, organic aerosol, and sea-salt particles collected during CalNex

    Science.gov (United States)

    Adachi, K.; Buseck, P. R.

    2010-12-01

    Anthropogenic aerosol particles are emitted in abundance from megacities. Those particles can have important effects on both human health and climate. In this study, aerosol particles having aerodynamic diameters between 50 and 300 nm were collected during the CalNex campaign at the Pasadena ground site from May 15 to June 15, 2010, ~15 km northeast of downtown Los Angeles. The samples were analyzed using transmission electron microscopes (TEMs) to characterize particle shapes and compositions. Most samples are dominated by soot, organic aerosol (OA), sulfate, sea salt, or combinations thereof. Sizes and amounts of OA particles increased during the afternoons, and most soot particles were internally mixed with OA and sulfate in the afternoons. The proportion of soot to other material in individual particles increased and soot particles were more compact during the nights and early mornings. Sea-salt particles were commonly internally mixed with other materials. They have high Na contents with lesser N, Mg, S, K, and Ca and almost no Cl, suggesting that the Cl was replaced by sulfate or nitrate in the atmosphere. There is less OA and more sea salt and sulfate in the CalNex samples than in the samples from Mexico City that were collected during the MILAGRO campaign. Our study indicates that compositions of internally mixed aerosol particles and shapes of soot particles change significantly within a day. These changes probably influence the estimates of their effects on human health and climate.

  12. Integrating biomass, sulphate and sea-salt aerosol responses into a microphysical chemical parcel model: implications for climate studies.

    Science.gov (United States)

    Ghosh, S; Smith, M H; Rap, A

    2007-11-15

    Aerosols are known to influence significantly the radiative budget of the Earth. Although the direct effect (whereby aerosols scatter and absorb solar and thermal infrared radiation) has a large perturbing influence on the radiation budget, the indirect effect (whereby aerosols modify the microphysical and hence the radiative properties and amounts of clouds) poses a greater challenge to climate modellers. This is because aerosols undergo chemical and physical changes while in the atmosphere, notably within clouds, and are removed largely by precipitation. The way in which aerosols are processed by clouds depends on the type, abundance and the mixing state of the aerosols concerned. A parametrization with sulphate and sea-salt aerosol has been successfully integrated within the Hadley Centre general circulation model (GCM). The results of this combined parametrization indicate a significantly reduced role, compared with previous estimates, for sulphate aerosol in cloud droplet nucleation and, consequently, in indirect radiative forcing. However, in this bicomponent system, the cloud droplet number concentration, N(d) (a crucial parameter that is used in GCMs for radiative transfer calculations), is a smoothly varying function of the sulphate aerosol loading. Apart from sea-salt and sulphate aerosol particles, biomass aerosol particles are also present widely in the troposphere. We find that biomass smoke can significantly perturb the activation and growth of both sulphate and sea-salt particles. For a fixed salt loading, N(d) increases linearly with modest increases in sulphate and smoke masses, but significant nonlinearities are observed at higher non-sea-salt mass loadings. This non-intuitive N(d) variation poses a fresh challenge to climate modellers.

  13. On the evaluation of global sea-salt aerosol models at coastal/orographic sites

    Science.gov (United States)

    Spada, M.; Jorba, O.; Pérez García-Pando, C.; Janjic, Z.; Baldasano, J. M.

    2015-01-01

    Sea-salt aerosol global models are typically evaluated against concentration observations at coastal stations that are unaffected by local surf conditions and thus considered representative of open ocean conditions. Despite recent improvements in sea-salt source functions, studies still show significant model errors in specific regions. Using a multiscale model, we investigated the effect of high model resolution (0.1° × 0.1° vs. 1° × 1.4°) upon sea-salt patterns in four stations from the University of Miami Network: Baring Head, Chatam Island, and Invercargill in New Zealand, and Marion Island in the sub-antarctic Indian Ocean. Normalized biases improved from +63.7% to +3.3% and correlation increased from 0.52 to 0.84. The representation of sea/land interfaces, mesoscale circulations, and precipitation with the higher resolution model played a major role in the simulation of annual concentration trends. Our results recommend caution when comparing or constraining global models using surface concentration observations from coastal stations.

  14. Sea salt

    OpenAIRE

    Galvis-Sánchez, Andrea C.; Lopes, João Almeida; Delgadillo, Ivone; Rangel, António O. S. S.

    2013-01-01

    The geographical indication (GI) status links a product with the territory and with the biodiversity involved. Besides, the specific knowledge and cultural practices of a human group that permit transforming a resource into a useful good is protected under a GI designation. Traditional sea salt is a hand-harvested product originating exclusively from salt marshes from specific geographical regions. Once salt is harvested, no washing, artificial drying or addition of anti-caking agents are all...

  15. Heterogeneous Ice Nucleation Ability of NaCl and Sea Salt Aerosol Particles at Cirrus Temperatures

    Science.gov (United States)

    Wagner, Robert; Kaufmann, Julia; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Ullrich, Romy; Leisner, Thomas

    2018-03-01

    In situ measurements of the composition of heterogeneous cirrus ice cloud residuals have indicated a substantial contribution of sea salt in sampling regions above the ocean. We have investigated the heterogeneous ice nucleation ability of sodium chloride (NaCl) and sea salt aerosol (SSA) particles at cirrus cloud temperatures between 235 and 200 K in the Aerosol Interaction and Dynamics in the Atmosphere aerosol and cloud chamber. Effloresced NaCl particles were found to act as ice nucleating particles in the deposition nucleation mode at temperatures below about 225 K, with freezing onsets in terms of the ice saturation ratio, Sice, between 1.28 and 1.40. Above 225 K, the crystalline NaCl particles deliquesced and nucleated ice homogeneously. The heterogeneous ice nucleation efficiency was rather similar for the two crystalline forms of NaCl (anhydrous NaCl and NaCl dihydrate). Mixed-phase (solid/liquid) SSA particles were found to act as ice nucleating particles in the immersion freezing mode at temperatures below about 220 K, with freezing onsets in terms of Sice between 1.24 and 1.42. Above 220 K, the SSA particles fully deliquesced and nucleated ice homogeneously. Ice nucleation active surface site densities of the SSA particles were found to be in the range between 1.0 · 1010 and 1.0 · 1011 m-2 at T < 220 K. These values are of the same order of magnitude as ice nucleation active surface site densities recently determined for desert dust, suggesting a potential contribution of SSA particles to low-temperature heterogeneous ice nucleation in the atmosphere.

  16. Biogenic, anthropogenic and sea salt sulfate size-segregated aerosols in the Arctic summer

    Directory of Open Access Journals (Sweden)

    R. Ghahremaninezhad

    2016-04-01

    Full Text Available Size-segregated aerosol sulfate concentrations were measured on board the Canadian Coast Guard Ship (CCGS Amundsen in the Arctic during July 2014. The objective of this study was to utilize the isotopic composition of sulfate to address the contribution of anthropogenic and biogenic sources of aerosols to the growth of the different aerosol size fractions in the Arctic atmosphere. Non-sea-salt sulfate is divided into biogenic and anthropogenic sulfate using stable isotope apportionment techniques. A considerable amount of the average sulfate concentration in the fine aerosols with a diameter  <  0.49 µm was from biogenic sources (>  63 %, which is higher than in previous Arctic studies measuring above the ocean during fall (<  15 % (Rempillo et al., 2011 and total aerosol sulfate at higher latitudes at Alert in summer (>  30 % (Norman et al., 1999. The anthropogenic sulfate concentration was less than that of biogenic sulfate, with potential sources being long-range transport and, more locally, the Amundsen's emissions. Despite attempts to minimize the influence of ship stack emissions, evidence from larger-sized particles demonstrates a contribution from local pollution. A comparison of δ34S values for SO2 and fine aerosols was used to show that gas-to-particle conversion likely occurred during most sampling periods. δ34S values for SO2 and fine aerosols were similar, suggesting the same source for SO2 and aerosol sulfate, except for two samples with a relatively high anthropogenic fraction in particles  <  0.49 µm in diameter (15–17 and 17–19 July. The high biogenic fraction of sulfate fine aerosol and similar isotope ratio values of these particles and SO2 emphasize the role of marine organisms (e.g., phytoplankton, algae, bacteria in the formation of fine particles above the Arctic Ocean during the productive summer months.

  17. Nuclear risk reduction study. The effect of sea salt aerosols in the Japan sea coast facilities

    International Nuclear Information System (INIS)

    Nakayasu, Fumio

    2007-01-01

    All of 15 nuclear power plants in Fukui Prefecture are located in the Japan Sea Coast. Corrosion is strongly influenced by material and environmental factors. We installed the salt damage experimental yard at Awara sea coast in March, 2006. We are doing the open air test, sheltered test without filter and with filter. The carbon steel standard specimen were exposed under three kinds of test conditions mentioned above. The corrosivity of the open air test specimens was higher than it of Miyako Island, Okinawa. The corrosivity of carbon steel of winter was higher than it of summer. The measurement of chloride deposition rate was done by the dry gauze method. The correlation between chloride deposition rate and the average velocity of the wind was found. The correlation between chloride deposition rate and the average rainfall was a little complicate. It means the chloride deposition rate has maximum value at a certain rainfall amount. No other clear relation was found. (author)

  18. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... of a cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...... a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...

  19. HALIPP. Photocatalysis of tropospheric chemistry by sea salt. Final report; HALIPP. Photokatalyse der Luftchemie durch Seesalz-Aerosole. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Zetzsch, C; Scheer, V; Krueger, H U; Behnke, W

    1994-12-31

    The reactions of gaseous NO{sub 2} and N{sub 2}O{sub 5} with humidified NaCl-aerosol and humidified mixed NaCl/NaNO{sub 3}- and NaCl/Na{sub 2}SO{sub 4} -aerosols and of gaseous O{sub 3} with humidified sea-salt aerosol were investigated. An upper limit of <10{sup 4} was estimated for the uptake coefficient of NO{sub 2} from our measurements, the uptake coefficient of N{sub 2}O{sub 5} was determined to be 0.032{+-}0.003 (stated error: {+-}2{sigma}). Instead of NOCl reported as a product from NaCl in the literature, HONO is formed from the reaction of NO{sub 2} with deliquescent NaCl aerosol. Gaseaous N{sub 2}O{sub 5} is converted to gaseous CINO{sub 2} below relative humidities of 94%. Only at much higher humidities the formation of 2 HNO{sub 3} increases. No precursors of atomic Cl are observed to be formed from gaseous ozone and pure NaCl-aerosol. Only in the presence of seal-salt aerosols a formation of Cl{sub 2} is found (although not yet quantified). (orig.) [Deutsch] Es wurde die Reaktion von gasfoermigem NO{sub 2} und N{sub 2}O{sub 5} mit feuchtem NaCl- und gemischtem NaCl/NaNO{sub 3}- und NaCl/Na{sub 2}SO{sub 4}- Aerosol sowie von gasfoermigem O{sub 3} mit feuchtem Seesalzaerosol untersucht. Der Uptake-Koeffizient von NO{sub 2} wurde mit kleiner 10{sup -4} abgeschaetzt, der von N{sub 2}O{sub 5} mit 0.032{+-}0.003 (2{sigma}-Fehler) bestimmt. In Gegenwart von NO{sub 2} bildet sich anstelle des in der Literatur angegebenen NOCl gasfoermigs HONO und in Gegenwart von N{sub 2}O{sub 5} unterhalb einer relativen Feuchte von 94% hauptsaechlich gasfoermiges ClNO{sub 2}. Erst in Gegenwart wesentlich hoeherer Feuchten nimmt die Bildung von 2HNO{sub 3} zu. In Gegenwart von Ozon und reinem NaCl-Aerosol bilden sich keine Chloratomvorlaeufer. Erst in Gegenwart von Seesalzaerosolen kommt es zur Bildung von Cl{sub 2}. Eine Quantifizierung dieser letzteren Ergebnisse wurde noch nicht durchgefuehrt. (orig.)

  20. Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing

    Science.gov (United States)

    Ueda, S.; Hirose, Y.; Miura, K.; Okochi, H.

    2014-02-01

    Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, Japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 μm diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or Cl. Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without Cl. However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in

  1. Determination of pollution for the effect of sea salt aerosols corrosion

    International Nuclear Information System (INIS)

    Nakayasu, Fumio; Umehara, Toshihiro; Mizutani, Masatoshi; Matsukawa, Kiyokazu

    2007-01-01

    All of 15 nuclear power plants in Fukui Prefecture are located in the Japan Sea Coast. Corrosion is strongly influenced by material and environmental factors. We installed the salt damage experimental yard at Awara sea coast in March, 2006. We are doing the open air test, sheltered test without filter and with filter. The corrosivity of carbon steel of winter was higher than it of summer at Awara facility. The measurement of chloride deposition rate was done by the dry gauze method. The correlation between chloride deposition rate and the average velocity of the wind was found. The correlation between chloride deposition rate and the average rainfall was a little complicate. It means the chloride deposition rate has maximum value at a certain rainfall amount. No other clear relation was found. (author)

  2. Accessing the Impact of Sea-Salt Emissions on Aerosol Chemical Formation and Deposition Over Pearl River Delta, China

    Science.gov (United States)

    Fan, Q.; Wang, X.; Liu, Y.; Wu, D.; Chan, P. W.; Fan, S.; Feng, Y.

    2015-12-01

    Sea-salt aerosol (SSA) emissions have a significant impact on aerosol pollution and haze formation in the coastal areas. In this study, Models-3/CMAQ modeling system was utilized to access the impact of SSA emissions on aerosol chemical formation and deposition over Pearl River Delta (PRD), China in July 2006. More SSAs were transported inland from the open-ocean under the southeast wind in summertime. Two experiments (with and without SSA emissions in the CMAQ model) were set up to compare the modeling results with each other. The results showed that the increase of sulfate concentrations were more attributable to the primary emissions of coarse SO42- particles in SSA, while the increase of nitrate concentrations were more attributable to secondary chemical formations, known as the mechanisms of chloride depletion in SSA. In the coastal areas, 17.62 % of SO42-, 26.6% of NO3- and 38.2% of PM10 were attributed to SSA emissions, while those portions were less than 1% in the inland areas. The increases of PM10 and its components due to SSA emissions resulted in higher deposition fluxes over PRD, particularly in the coastal areas, except for the wet deposition of nitrate. Nitrate was more sensitive to SSA emissions in chemical formations than sulfate and dry deposition of aerosol was also more sensitive than that for wet deposition. Process analysis of sulfate and nitrate was applied to find out the difference of physical and chemical mechanisms between Guangzhou (the inland areas) and Zhuhai (the coastal areas). The negative contributions of dry deposition process to both sulfate and nitrate concentrations increased if SSA emissions were taken into account in the model, especially for Zhuhai. The negative contributions of cloud process also increased due to cloud scavenging and wet deposition process. In the coastal area, the gas-to-particle conversions became more active with high contributions of aerosol process to nitrate concentrations.

  3. Climatic responses to the shortwave and longwave direct radiative effects of sea salt aerosol in present day and the last glacial maximum

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Xu [Chinese Academy of Sciences (CAS), Climate Change Research Center (CCRC), Beijing (China); Chinese Academy of Sciences (CAS), Nansen-Zhu International Research Center, Institute of Atmospheric Physics (IAP), Beijing (China); Harvard University, School of Engineering and Applied Sciences, Cambridge, MA (United States); Liao, Hong [Chinese Academy of Sciences (CAS), State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), P.O. Box 9804, Beijing (China)

    2012-12-15

    We examine the climatic responses to the shortwave (SW) and longwave (LW) direct radiative effects (RE) of sea salt aerosol in present day and the last glacial maximum (LGM) using a general circulation model with online simulation of sea salt cycle. The 30-year control simulation predicts a present-day annual emission of sea salt of 4,253 Tg and a global burden of 8.1 Tg for the particles with dry radii smaller than 10 {mu}m. Predicted annual and global mean SW and LW REs of sea salt are, respectively, -1.06 and +0.14 W m{sup -2} at the top of atmosphere (TOA), and -1.10 and +0.54 W m{sup -2} at the surface. The LW warming of sea salt is found to decrease with altitude, which leads to a stronger net sea salt cooling in the upper troposphere. The changes in global mean air temperature by the present-day sea salt are simulated to be -0.55, -0.63, -0.86, and -0.91 K at the surface, 850, 500a, and 200 hPa, respectively. The emission of sea salt at the LGM is estimated to be 4,075 Tg year{sup -1}. Relative to present day, the LGM sea salt emission is higher by about 18% over the tropical and subtropical oceans, and is lower by about 35% in the mid- and high-latitudes in both hemispheres because of the expansion of sea ice. As a result of the weakened LGM water cycle, the LGM annual and global mean burden of sea salt is predicted to be higher by 4% as compared to the present-day value. Compared with the climatic effect of sea salt in present day, the sea-salt-induced reductions in surface air temperature at the LGM have similar magnitude in the tropics but are weakened by about 0.18 and 0.14 K in the high latitudes of the Southern and Northern Hemispheres, respectively. We also perform a sensitivity study to explore the upper limit of the climatic effect of the LGM sea salt. We assume an across-the-board 30% increase in the glacial wind speed and consider sea salt emissions over sea ice, so that the model can reproduce the ratio of sea salt deposition between the LGM and

  4. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2012-05-01

    Full Text Available The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g. However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate – which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ≈0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882±0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2(g → multiple steps → SOOCl2−. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32− by O3 (αseasalt = 1.0124±0.0017 at 19 °C. Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29% of S(IV oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways – oxidation by O3 and by Cl catalysis (α34 = 1.0163±0.0018 at 19 °C in pure water or 1.0199±0.0024 at pH = 7.2 – which favour the heavy isotope, and

  5. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    Science.gov (United States)

    Harris, E.; Sinha, B.; Hoppe, P.; Foley, S.; Borrmann, S.

    2012-05-01

    The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate - which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ≈0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882±0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2(g) → multiple steps → SOOCl2-. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32- by O3 (αseasalt = 1.0124±0.0017 at 19 °C). Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29% of S(IV) oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways - oxidation by O3 and by Cl catalysis (α34 = 1.0163±0.0018 at 19 °C in pure water or 1.0199±0.0024 at pH = 7.2) - which favour the heavy isotope, and the alkalinity non

  6. Modeling and Evaluation of the Global Sea-Salt Aerosol Distribution: Sensitivity to Emission Schemes and Resolution Effects at Coastal/Orographic Sites

    Science.gov (United States)

    Spada, M.; Jorba, O.; Perez Garcia-Pando, C.; Janjic, Z.; Baldasano, J. M.

    2013-01-01

    One of the major sources of uncertainty in model estimates of the global sea-salt aerosol distribution is the emission parameterization. We evaluate a new sea-salt aerosol life cycle module coupled to the online multi-scale chemical transport model NMMB/BSC-CTM. We compare 5 year global simulations using five state-of-the-art sea-salt open-ocean emission schemes with monthly averaged coarse aerosol optical depth (AOD) from selected AERONET sun photometers, surface concentration measurements from the University of Miami's Ocean Aerosol Network, and measurements from two NOAA/PMEL cruises (AEROINDOEX and ACE1). Model results are highly sensitive to the introduction of sea-surface-temperature (SST)-dependent emissions and to the accounting of spume particles production. Emission ranges from 3888 teragrams per year to 8114 teragrams per year, lifetime varies between 7.3 hours and 11.3 hours, and the average column mass load is between 5.0 teragrams and 7.2 teragrams. Coarse AOD is reproduced with an overall correlation of around 0.5 and with normalized biases ranging from +8.8 percent to +38.8 percent. Surface concentration is simulated with normalized biases ranging from minus 9.5 percent to plus 28 percent and the overall correlation is around 0.5. Our results indicate that SST-dependent emission schemes improve the overall model performance in reproducing surface concentrations. On the other hand, they lead to an overestimation of the coarse AOD at tropical latitudes, although it may be affected by uncertainties in the comparison due to the use of all-sky model AOD, the treatment of water uptake, deposition and optical properties in the model and/or an inaccurate size distribution at emission.

  7. Sea Salt Aerosol, Atmospheric Radon and Meteorological Observations in the Western South Atlantic Ocean (February 1981).

    Science.gov (United States)

    1983-09-28

    approximately isokinetic sampling conditions. The blower motor for the hi-vol was separated from the filter holder unit by a one- meter length of flexible...bridge bulkhead about 15 m above sea level and within 3 meters of the ARCAS inlet. The flow rate through the 20 cm x 25 cm glass fiber filters was...materials, atmospheric pressure, soil moisture and vegetative cover (Larson and Bressan, 1980). Radon concentrations measured a few meters above

  8. Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    P. Jiménez-Guerrero

    2011-05-01

    Full Text Available A number of attempts have been made to incorporate sea-salt aerosol (SSA source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution for a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the particle size and the surface wind speed raised to the power 3.41. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around −0.002 and −1.2 μg m−3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA strongly vary across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m−3 and CMAQ in the Gulf of Lion (9 μg m−3. The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes

  9. Sea Salt vs. Table Salt: What's the Difference?

    Science.gov (United States)

    ... and healthy eating What's the difference between sea salt and table salt? Answers from Katherine Zeratsky, R.D., L.D. The main differences between sea salt and table salt are in their taste, texture ...

  10. Black Sea aerosols

    International Nuclear Information System (INIS)

    Hacisalihoglu, G.; Eliyakut, F.; Anwari, M.A.; Ataman, O.Y.; Balkas, T.I.; Tuncel, G.; Olmez, I.

    1991-01-01

    Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m 3 , which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

  11. Sea salt and pollution inputs over the continental United States

    International Nuclear Information System (INIS)

    Li, Y.-H.

    1992-01-01

    The average deposition rate of sea salt chloride over the world continents is about 10 meq m -2 yr -1 . Only about 14±1% of chloride in the pollution-corrected world average river is contributed by sea salt aerosols and the rest from the dissolution of evaporites. The significant increase of the ion concentrations in the Mississippi river from the year 1905 to 1987 was caused by anthropogenic inputs such as fossil fuel burning, common salt consumption, and dissolution of carbonate and silicate rocks by acids derived from acid precipitation. 29 refs., 4 figs., 3 tabs

  12. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

    Data.gov (United States)

    U.S. Environmental Protection Agency — The uploaded data consists of the BRACE Na aerosol observations paired with CMAQ model output, the updated model's parameterization of sea salt aerosol emission size...

  13. Changes in Sea Salt Emissions Enhance ENSO Variability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang; Russell, Lynn M.; Lou, Sijia; Lamjiri, Maryam A.; Liu, Ying; Singh, Balwinder; Ghan, Steven J.

    2016-11-15

    Two 150-year pre-industrial simulations with and without interactive sea salt emissions from the Community Earth System Model (CESM) are performed to quantify the interactions between sea salt emissions and El Niño–Southern Oscillation (ENSO). Variations in sea salt emissions over the tropical Pacific Ocean are affected by changing wind speed associated with ENSO variability. ENSO-induced interannual variations in sea salt emissions result in decreasing (increasing) aerosol optical depth (AOD) by 0.03 over the equatorial central-eastern (western) Pacific Ocean during El Niño events compared to those during La Niña events. These changes in AOD further increase (decrease) radiative fluxes into the atmosphere by +0.2 W m-2 (-0.4 W m-2) over the tropical eastern (western) Pacific. Thereby, sea surface temperature increases (decreases) by 0.2–0.4 K over the tropical eastern (western) Pacific Ocean during El Niño compared to La Niña events and enhances ENSO variability by 10%. The increase in ENSO amplitude is a result of systematic heating (cooling) during the warm (cold) phase, of ENSO in the eastern Pacific. Interannual variations in sea salt emissions then produce the anomalous ascent (subsidence) over the equatorial eastern (western) Pacific between El Niño and La Niña events, which is a result of heating anomalies. Due to variations in sea salt emissions, the convective precipitation is enhanced by 0.6–1.2 mm day-1 over the tropical central-eastern Pacific Ocean and weakened by 0.9–1.5 mm day-1 over the Maritime Continent during El Niño compared to La Niña events, enhancing the precipitation variability over the tropical Pacific.

  14. Eddy Covariance Measurements of the Sea-Spray Aerosol Flu

    Science.gov (United States)

    Brooks, I. M.; Norris, S. J.; Yelland, M. J.; Pascal, R. W.; Prytherch, J.

    2015-12-01

    Historically, almost all estimates of the sea-spray aerosol source flux have been inferred through various indirect methods. Direct estimates via eddy covariance have been attempted by only a handful of studies, most of which measured only the total number flux, or achieved rather coarse size segregation. Applying eddy covariance to the measurement of sea-spray fluxes is challenging: most instrumentation must be located in a laboratory space requiring long sample lines to an inlet collocated with a sonic anemometer; however, larger particles are easily lost to the walls of the sample line. Marine particle concentrations are generally low, requiring a high sample volume to achieve adequate statistics. The highly hygroscopic nature of sea salt means particles change size rapidly with fluctuations in relative humidity; this introduces an apparent bias in flux measurements if particles are sized at ambient humidity. The Compact Lightweight Aerosol Spectrometer Probe (CLASP) was developed specifically to make high rate measurements of aerosol size distributions for use in eddy covariance measurements, and the instrument and data processing and analysis techniques have been refined over the course of several projects. Here we will review some of the issues and limitations related to making eddy covariance measurements of the sea spray source flux over the open ocean, summarise some key results from the last decade, and present new results from a 3-year long ship-based measurement campaign as part of the WAGES project. Finally we will consider requirements for future progress.

  15. Variability of sea salts in ice and firn cores from Fimbul Ice Shelf, Dronning Maud Land, Antarctica

    Science.gov (United States)

    Paulina Vega, Carmen; Isaksson, Elisabeth; Schlosser, Elisabeth; Divine, Dmitry; Martma, Tõnu; Mulvaney, Robert; Eichler, Anja; Schwikowski-Gigar, Margit

    2018-05-01

    Major ions were analysed in firn and ice cores located at Fimbul Ice Shelf (FIS), Dronning Maud Land - DML, Antarctica. FIS is the largest ice shelf in the Haakon VII Sea, with an extent of approximately 36 500 km2. Three shallow firn cores (about 20 m deep) were retrieved in different ice rises, Kupol Ciolkovskogo (KC), Kupol Moskovskij (KM), and Blåskimen Island (BI), while a 100 m long core (S100) was drilled near the FIS edge. These sites are distributed over the entire FIS area so that they provide a variety of elevation (50-400 m a.s.l.) and distance (3-42 km) to the sea. Sea-salt species (mainly Na+ and Cl-) generally dominate the precipitation chemistry in the study region. We associate a significant sixfold increase in median sea-salt concentrations, observed in the S100 core after the 1950s, to an enhanced exposure of the S100 site to primary sea-salt aerosol due to a shorter distance from the S100 site to the ice front, and to enhanced sea-salt aerosol production from blowing salty snow over sea ice, most likely related to the calving of Trolltunga occurred during the 1960s. This increase in sea-salt concentrations is synchronous with a shift in non-sea-salt sulfate (nssSO42-) toward negative values, suggesting a possible contribution of fractionated aerosol to the sea-salt load in the S100 core most likely originating from salty snow found on sea ice. In contrast, there is no evidence of a significant contribution of fractionated sea salt to the ice-rises sites, where the signal would be most likely masked by the large inputs of biogenic sulfate estimated for these sites. In summary, these results suggest that the S100 core contains a sea-salt record dominated by the proximity of the site to the ocean, and processes of sea ice formation in the neighbouring waters. In contrast, the ice-rises firn cores register a larger-scale signal of atmospheric flow conditions and a less efficient transport of sea-salt aerosols to these sites. These findings are a

  16. The origin of sea salt in snow on Arctic sea ice and in coastal regions

    Directory of Open Access Journals (Sweden)

    F. Domine

    2004-01-01

    Full Text Available Snow, through its trace constituents, can have a major impact on lower tropospheric chemistry, as evidenced by ozone depletion events (ODEs in oceanic polar areas. These ODEs are caused by the chemistry of bromine compounds that originate from sea salt bromide. Bromide may be supplied to the snow surface by upward migration from sea ice, by frost flowers being wind-blown to the snow surface, or by wind-transported aerosol generated by sea spray. We investigate here the relative importance of these processes by analyzing ions in snow near Alert and Ny-Ålesund (Canadian and European high Arctic in winter and spring. Vertical ionic profiles in the snowpack on sea ice are measured to test upward migration of sea salt ions and to seek evidence for ion fractionation processes. Time series of the ionic composition of surface snow layers are investigated to quantify wind-transported ions. Upward migration of unfractionated sea salt to heights of at least 17cm was observed in winter snow, leading to Cl- concentration of several hundred µM. Upward migration thus has the potential to supply ions to surface snow layers. Time series show that wind can deposit aerosols to the top few cm of the snow, leading also to Cl- concentrations of several hundred µM, so that both diffusion from sea ice and wind transport can significantly contribute ions to snow. At Ny-Ålesund, sea salt transported by wind was unfractionated, implying that it comes from sea spray rather than frost flowers. Estimations based on our results suggest that the marine snowpack contains about 10 times more Na+ than the frost flowers, so that both the marine snowpack and frost flowers need to be considered as sea salt sources. Our data suggest that ozone depletion chemistry can significantly enhance the Br- content of snow. We speculate that this can also take place in coastal regions and contribute to propagate ODEs inland. Finally, we stress the need to measure snow physical parameters

  17. Seasonal variation of fractionated sea-salt particles on the Antarctic coast

    Science.gov (United States)

    Hara, K.; Osada, K.; Yabuki, M.; Yamanouchi, T.

    2012-09-01

    Aerosol sampling was conducted at Syowa Station, Antarctica (coastal station) in 2004-2006. SO42-depletion by mirabilite precipitation was identified from April through November. The fractionated sea-salt particles were distributed in ultrafine- coarse modes. Molar ratios of Mg2+/Na+ and K+/Na+ were higher than in bulk seawater ratio during winter-spring. The Mg2+/Na+ ratio in aerosols greatly exceeded the upper limit in the case only with mirabilite precipitation. The temperature dependence of Mg2+/Na+ ratio strongly suggested that higher ratios of Mg2+/Na+ and K+/Na+ were associated with sea-salt fractionation by precipitation of mirabilite at -9°C, hydrohalite at ca. -23°C and other salts such as ikaite at ca. -5°C and gypsum at ca. -22°C during winter-spring. Mg-salts with lower deliquescence relative humidity can be enriched gradually in the fractionated sea-salt particles. Results suggests that sea-salt fractionation can alter aerosol hygroscopicity and atmospheric chemistry in polar regions.

  18. Ice crystallization in ultrafine water-salt aerosols: nucleation, ice-solution equilibrium, and internal structure.

    Science.gov (United States)

    Hudait, Arpa; Molinero, Valeria

    2014-06-04

    Atmospheric aerosols have a strong influence on Earth's climate. Elucidating the physical state and internal structure of atmospheric aqueous aerosols is essential to predict their gas and water uptake, and the locus and rate of atmospherically important heterogeneous reactions. Ultrafine aerosols with sizes between 3 and 15 nm have been detected in large numbers in the troposphere and tropopause. Nanoscopic aerosols arising from bubble bursting of natural and artificial seawater have been identified in laboratory and field experiments. The internal structure and phase state of these aerosols, however, cannot yet be determined in experiments. Here we use molecular simulations to investigate the phase behavior and internal structure of liquid, vitrified, and crystallized water-salt ultrafine aerosols with radii from 2.5 to 9.5 nm and with up to 10% moles of ions. We find that both ice crystallization and vitrification of the nanodroplets lead to demixing of pure water from the solutions. Vitrification of aqueous nanodroplets yields nanodomains of pure low-density amorphous ice in coexistence with vitrified solute rich aqueous glass. The melting temperature of ice in the aerosols decreases monotonically with an increase of solute fraction and decrease of radius. The simulations reveal that nucleation of ice occurs homogeneously at the subsurface of the water-salt nanoparticles. Subsequent ice growth yields phase-segregated, internally mixed, aerosols with two phases in equilibrium: a concentrated water-salt amorphous mixture and a spherical cap-like ice nanophase. The surface of the crystallized aerosols is heterogeneous, with ice and solution exposed to the vapor. Free energy calculations indicate that as the concentration of salt in the particles, the advance of the crystallization, or the size of the particles increase, the stability of the spherical cap structure increases with respect to the alternative structure in which a core of ice is fully surrounded by

  19. Size Resolved Measurements of Springtime Aerosol Particles over the Northern South China Sea

    Science.gov (United States)

    Atwood, Samuel A.; Reid, Jeffrey S.; Kreidenweis, Sonia M.; Cliff, Stephen S.; Zhao, Yongjing; Lin, Neng-Huei; Tsay, Si-Chee; Chu, Yu-Chi; Westphal, Douglas L.

    2012-01-01

    Large sources of aerosol particles and their precursors are ubiquitous in East Asia. Such sources are known to impact the South China Sea (henceforth SCS), a sometimes heavily polluted region that has been suggested as particularly vulnerable to climate change. To help elucidate springtime aerosol transport into the SCS, an intensive study was performed on the remote Dongsha (aka Pratas) Islands Atoll in spring 2010. As part of this deployment, a Davis Rotating-drum Uniform size-cut Monitor (DRUM) cascade impactor was deployed to collect size-resolved aerosol samples at the surface that were analyzed by X-ray fluorescence for concentrations of selected elements. HYSPLIT backtrajectories indicated that the transport of aerosol observed at the surface at Dongsha was occurring primarily from regions generally to the north and east. This observation was consistent with the apparent persistence of pollution and dust aerosol, along with sea salt, in the ground-based dataset. In contrast to the sea-level observations, modeled aerosol transport suggested that the westerly flow aloft (w700 hPa) transported smoke-laden air toward the site from regions from the south and west. Measured aerosol optical depth at the site was highest during time periods of modeled heavy smoke loadings aloft. These periods did not coincide with elevated aerosol concentrations at the surface, although the model suggested sporadic mixing of this free-tropospheric aerosol to the surface over the SCS. A biomass burning signature was not clearly identified in the surface aerosol composition data, consistent with this aerosol type remaining primarily aloft and not mixing strongly to the surface during the study. Significant vertical wind shear in the region also supports the idea that different source regions lead to varying aerosol impacts in different vertical layers, and suggests the potential for considerable vertical inhomogeneity in the SCS aerosol environment.

  20. Can salt marshes survive sea level rise ?

    Science.gov (United States)

    Tambroni, N.; Seminara, G.

    2008-12-01

    Stability of salt marshes is a very delicate issue depending on the subtle interplay among hydrodynamics, morphodynamics and ecology. In fact, the elevation of the marsh platform depends essentially on three effects: i) the production of soil associated with sediments resuspended by tidal currents and wind waves in the adjacent tidal flats, advected to the marsh and settling therein; ii) production of organic sediments by the salt marsh vegetation; iii) soil 'loss' driven by sea level rise and subsidence. In order to gain insight into the mechanics of the process, we consider a schematic configuration consisting of a salt marsh located at the landward end of a tidal channel connected at the upstream end with a tidal sea, under different scenarios of sea level rise. We extend the simple 1D model for the morphodynamic evolution of a tidal channel formulated by Lanzoni and Seminara (2002, Journal of Geophysical Research-Oceans, 107, C1) allowing for sediment resuspension in the channel and vegetation growth in the marsh using the depth dependent model of biomass productivity of Spartina proposed by Morris et al. (2002, Ecology, 83, pp. 2869 - 2877). We first focus on the case of a tide dominated salt marsh neglecting wind driven sediment resuspension in the shoal. Results show that the production of biomass plays a crucial role on salt marsh stability and, provided productivity is high enough, it may turn out to be sufficient to counteract the effects of sea level rise even in the absence of significant supply of mineral sediments. The additional effect of wind resuspension is then introduced. Note that the wind action is twofold: on one hand, it generates wind waves the amplitude of which is strongly dependent on shoal depth and wind fetch; on the other hand, it generates currents driven by the surface setup induced by the shear stress acting on the free surface. Here, each contribution is analysed separately. Results show that the values of bottom stress induced by

  1. The Impact of Aerosol Particle Mixing State on the Hygroscopicity of Sea Spray Aerosol.

    Science.gov (United States)

    Schill, Steven R; Collins, Douglas B; Lee, Christopher; Morris, Holly S; Novak, Gordon A; Prather, Kimberly A; Quinn, Patricia K; Sultana, Camille M; Tivanski, Alexei V; Zimmermann, Kathryn; Cappa, Christopher D; Bertram, Timothy H

    2015-06-24

    Aerosol particles influence global climate by determining cloud droplet number concentrations, brightness, and lifetime. Primary aerosol particles, such as those produced from breaking waves in the ocean, display large particle-particle variability in chemical composition, morphology, and physical phase state, all of which affect the ability of individual particles to accommodate water and grow into cloud droplets. Despite such diversity in molecular composition, there is a paucity of methods available to assess how particle-particle variability in chemistry translates to corresponding differences in aerosol hygroscopicity. Here, an approach has been developed that allows for characterization of the distribution of aerosol hygroscopicity within a chemically complex population of atmospheric particles. This methodology, when applied to the interpretation of nascent sea spray aerosol, provides a quantitative framework for connecting results obtained using molecular mimics generated in the laboratory with chemically complex ambient aerosol. We show that nascent sea spray aerosol, generated in situ in the Atlantic Ocean, displays a broad distribution of particle hygroscopicities, indicative of a correspondingly broad distribution of particle chemical compositions. Molecular mimics of sea spray aerosol organic material were used in the laboratory to assess the volume fractions and molecular functionality required to suppress sea spray aerosol hygroscopicity to the extent indicated by field observations. We show that proper accounting for the distribution and diversity in particle hygroscopicity and composition are important to the assessment of particle impacts on clouds and global climate.

  2. Sea salts as a potential source of food spoilage fungi.

    Science.gov (United States)

    Biango-Daniels, Megan N; Hodge, Kathie T

    2018-02-01

    Production of sea salt begins with evaporation of sea water in shallow pools called salterns, and ends with the harvest and packing of salts. This process provides many opportunities for fungal contamination. This study aimed to determine whether finished salts contain viable fungi that have the potential to cause spoilage when sea salt is used as a food ingredient by isolating fungi on a medium that simulated salted food with a lowered water activity (0.95 a w ). The viable filamentous fungi from seven commercial salts were quantified and identified by DNA sequencing, and the fungal communities in different salts were compared. Every sea salt tested contained viable fungi, in concentrations ranging from 0.07 to 1.71 colony-forming units per gram of salt. In total, 85 fungi were isolated representing seven genera. One or more species of the most abundant genera, Aspergillus, Cladosporium, and Penicillium was found in every salt. Many species found in this study have been previously isolated from low water activity environments, including salterns and foods. We conclude that sea salts contain many fungi that have potential to cause food spoilage as well as some that may be mycotoxigenic. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

    Directory of Open Access Journals (Sweden)

    J. Sciare

    2003-01-01

    Full Text Available A detailed study on the temporal variability of compounds important in controlling aerosol chemical composition was performed during a one-month experiment conducted during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea. Contribution of different aerosol sources in the Eastern Mediterranean Basin could be investigated at this location since the site is influenced by a wide range of air masses originating mainly in Europe and Africa. Chemical apportionment was performed for various air mass origins and showed a strong impact of anthropogenic emissions in the Turkey and Central Europe sectors, with black carbon (BC and non-sea-salt sulfate (nss-SO4 concentrations higher than observed in the Eastern and Western Europe sectors. High levels of non-sea-salt calcium (nss-Ca were associated with air masses from Africa but also from Central Turkey. Evidence was found that BC calculation based on light absorbance during dust events was biased. This quality-controlled high temporal resolution dataset allowed to investigate in detail the source-receptor relationships responsible for the levels of BC, nss-SO4 and sulfur dioxide (SO2, observed in Crete. Among the results obtained from this model, the major contribution of Turkey and Central Europe was confirmed in terms of anthropogenic emissions. Comparisons with remote optical properties obtained from Satellite observations (SEAWIFS north of Crete indicates that our ground based aerosol characterization was suitable for describing aerosol properties in the atmospheric column for most of the time during the campaign.

  4. Global modelling of direct and indirect effects of sea spray aerosol using a source function encapsulating wave state

    Directory of Open Access Journals (Sweden)

    A.-I. Partanen

    2014-11-01

    Full Text Available Recently developed parameterizations for the sea spray aerosol source flux, encapsulating wave state, and its organic fraction were incorporated into the aerosol–climate model ECHAM-HAMMOZ to investigate the direct and indirect radiative effects of sea spray aerosol particles. Our simulated global sea salt emission of 805 Tg yr−1 (uncertainty range 378–1233 Tg yr−1 was much lower than typically found in previous studies. Modelled sea salt and sodium ion concentrations agreed relatively well with measurements in the smaller size ranges at Mace Head (annual normalized mean model bias −13% for particles with vacuum aerodynamic diameter Dva Da Da Da −2, in contrast to previous studies. This positive effect was ascribed to the tendency of sea salt aerosol to suppress both the in-cloud supersaturation and the formation of cloud condensation nuclei from sulfate. These effects can be accounted for only in models with sufficiently detailed aerosol microphysics and physics-based parameterizations of cloud activation. However, due to a strong negative direct effect, the simulated effective radiative forcing (total radiative effect was −0.2 W m−2. The simulated radiative effects of the primary marine organic emissions were small, with a direct effect of 0.03 W m−2 and an indirect effect of −0.07 W m−2.

  5. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    Directory of Open Access Journals (Sweden)

    R. S. Humphries

    2016-02-01

    Full Text Available Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3 concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between

  6. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    Science.gov (United States)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2016-02-01

    Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of

  7. Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

    Science.gov (United States)

    Sasakawa, Motoki; Uematsu, Mitsuo

    2002-12-01

    Samples of aerosol, sea fog, and rainwater were collected during a research cruise in the northwestern North Pacific, the Sea of Okhotsk, and the Sea of Japan in the summer of 1998. High concentrations of NO3-, nss-SO42- and NH4+ in aerosol over the Sea of Japan suggest that anthropogenic substances were transported to this region. Although the Sea of Okhotsk was covered with a clean marine air mass, the concentration of nss-SO42- was comparatively high in the aerosol samples. This nss-SO42- is probably of marine biogenic origin. The pH values of fogwater samples were measured to be fogwater collected over the Sea of Japan were higher than those in the other regions, suggesting that the sea fog scavenged anthropogenic substances. The concentration of nss-SO42- in fogwater over the Sea of Okhotsk was equivalent to that over the Sea of Japan, probably because nss-SO42- and SO2 of marine biogenic origin were scavenged by the sea fog over the Sea of Okhotsk. The pH values of rainwater samples ranged from 6.1 to 7.2 during the cruise, and acidification of the rain was not significant. The concentrations of nss-Ca2+ in the rainwater were higher than those of the fogwater. This suggests that the rain-scavenged continental CaCO3 may have existed above the lower marine boundary layer, where sea fog appeared. Comparisons of the composition of aerosol and fogwater indicated that coarse particles, such as sea salts predominantly act as condensation nuclei of sea fog droplets rather than fine particles such as (NH4)2SO4.

  8. Updating Sea Spray Aerosol Emissions in the Community Multiscale Air Quality Model

    Science.gov (United States)

    Gantt, B.; Bash, J. O.; Kelly, J.

    2014-12-01

    Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions, include sea surface temperature (SST) dependency, and revise surf zone emissions. Based on evaluation with several regional and national observational datasets in the continental U.S., the updated emissions generally improve surface concentrations predictions of primary aerosols composed of sea-salt and secondary aerosols affected by sea-salt chemistry in coastal and near-coastal sites. Specifically, the updated emissions lead to better predictions of the magnitude and coastal-to-inland gradient of sodium, chloride, and nitrate concentrations at Bay Regional Atmospheric Chemistry Experiment (BRACE) sites near Tampa, FL. Including SST-dependency to the SSA emission parameterization leads to increased sodium concentrations in the southeast U.S. and decreased concentrations along the Pacific coast and northeastern U.S., bringing predictions into closer agreement with observations at most Interagency Monitoring of Protected Visual Environments (IMPROVE) and Chemical Speciation Network (CSN) sites. Model comparison with California Research at the Nexus of Air Quality and Climate Change (CalNex) observations will also be discussed, with particular focus on the South Coast Air Basin where clean marine air mixes with anthropogenic pollution in a complex environment. These SSA emission updates enable more realistic simulation of chemical processes in coastal environments, both in clean marine air masses and mixtures of clean marine and polluted conditions.

  9. Characterization of aerosol over the Northern South China Sea during two cruises in 2003

    Science.gov (United States)

    Zhang, Xingying; Zhuang, Guoshun; Guo, Jinghua; Yin, Kedong; Zhang, Peng

    Atmospheric transport of trace elements has been found to be an important pathway for their input to the ocean. TSP, PM10, and PM2.5 aerosol samples were collected over the Northern South China Sea in two cruises in 2003 to estimate the input of aerosol from continent to the ocean. About 23 elements and 14 soluble ions in aerosol samples were measured. The average mass concentration of TSP in Cruise I in January (78 μg m -3) was ˜twice of that in Cruise II in April (37 μg m -3). Together with the crustal component, heavy metals from pollution sources over the land (especially from the industry and automobiles in Guangzhou) were transported to and deposited into the ocean. The atmospheric MSA concentrations in PM2.5 (0.048 μg m -3 in Cruise I and 0.043 μg m -3 in Cruise II) over Northern South China Sea were comparable to those over other coastal regions. The ratio of non-sea-salt (NSS)-sulfate to MSA is 103-655 for Cruise I and 15-440 for Cruise II in PM2.5 samples, which were much higher than those over remote oceans. The estimated anthropogenic sulfate accounts for 83-98% in Cruise I and 63-95% in Cruise II of the total NSS-sulfate. Fe (II) concentration in the aerosols collected over the ocean ranged from 0.1 to 0.9 μg m -3, accounting for 16-82% of the total iron in the aerosol, which could affect the marine biogeochemical cycle greatly.

  10. Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

    Science.gov (United States)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2012-01-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote

  11. Sea spray aerosol fluxes in the Baltic Sea region: Comparison of the WAM model with measurements

    Science.gov (United States)

    Markuszewski, Piotr; Kosecki, Szymon; Petelski, Tomasz

    2017-08-01

    Sea spray aerosol flux is an important element of sub-regional climate modeling. The majority of works related to this topic concentrate on open ocean research rather than on smaller, inland seas, e.g., the Baltic Sea. The Baltic Sea is one of the largest brackish inland seas by area, where major inflows of oceanic waters are rare. Furthermore, surface waves in the Baltic Sea have a relatively shorter lifespan in comparison with oceanic waves. Therefore, emission of sea spray aerosol may differ greatly from what is known from oceanic research and should be investigated. This article presents a comparison of sea spray aerosol measurements carried out on-board the s/y Oceania research ship with data calculated in accordance to the WAM model. The measurements were conducted in the southern region of the Baltic Sea during four scientific cruises. The gradient method was used to determinate aerosol fluxes. The fluxes were calculated for particles of diameter in range of 0.5-47 μm. The correlation between wind speed measured and simulated has a good agreement (correlation in range of 0.8). The comparison encompasses three different sea spray generation models. First, function proposed by Massel (2006) which is based only on wave parameters, such as significant wave height and peak frequency. Second, Callaghan (2013) which is based on Gong (2003) model (wind speed relation), and a thorough experimental analysis of whitecaps. Third, Petelski et al. (2014) which is based on in-situ gradient measurements with the function dependent on wind speed. The two first models which based on whitecaps analysis are insufficient. Moreover, the research shows strong relation between aerosol emission and wind speed history.

  12. Sea Spray Aerosol Production over the North Atlantic

    Science.gov (United States)

    Bates, T. S.; Quinn, P.

    2017-12-01

    Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding seawater. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosol (SSA), a mixture of organic and inorganic compounds with the organic matter enriched relative to seawater. SSA mass is well documented as the dominant component of aerosol light scattering over the remote oceans. The importance of SSA number to marine boundary layer cloud condensation nuclei (CCN) is much less certain. During the Western Atlantic Climate Study cruises (WACS-1 - August 2012 and WACS-2 - May-June 2014) and the North Atlantic Aerosols and Marine Ecosystem Study cruises (NAAMES-1 - November 2015, NAAMES-2 - May 2016, and NAAMES-3 - September 2017), we generated and measured freshly emitted SSA using the Sea Sweep SSA generator. During the 2017 cruise we also generated SSA with a Marine Aerosol Reference Tank (MART). Using the data generated on these 5 cruises and a large database of remote marine boundary layer aerosol measurements we will address three questions during this presentation: 1 - Do phytoplankton ecosystems affect the organic enrichment of freshly emitted SSA?, 2 - Do plankton ecosystems affect the number production flux of SSA?, and 3 - Is SSA a significant source of atmospheric CCN?

  13. Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

    Science.gov (United States)

    Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2018-04-01

    While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

  14. Quantifying the climatological cloud-free direct radiative forcing of aerosol over the Red Sea

    KAUST Repository

    Brindley, Helen; Osipov, Serega; Bantges, Richard; Smirnov, Alexander; Banks, Jamie; Levy, Robert; Prakash, P.-Jish; Stenchikov, Georgiy L.

    2015-01-01

    for assessing aerosol loading over the Sea. However, agreement between aerosol properties inferred from measurements from different instruments, and even in some cases from the same measurements using different retrieval algorithms can be poor, particularly

  15. Secondary sulfate is internally mixed with sea spray aerosol and organic aerosol in the winter Arctic

    Science.gov (United States)

    Kirpes, Rachel M.; Bondy, Amy L.; Bonanno, Daniel; Moffet, Ryan C.; Wang, Bingbing; Laskin, Alexander; Ault, Andrew P.; Pratt, Kerri A.

    2018-03-01

    Few measurements of aerosol chemical composition have been made during the winter-spring transition (following polar sunrise) to constrain Arctic aerosol-cloud-climate feedbacks. Herein, we report the first measurements of individual particle chemical composition near Utqiaġvik (Barrow), Alaska, in winter (seven sample days in January and February 2014). Individual particles were analyzed by computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX, 24 847 particles), Raman microspectroscopy (300 particles), and scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS, 290 particles). Sea spray aerosol (SSA) was observed in all samples, with fresh and aged SSA comprising 99 %, by number, of 2.5-7.5 µm diameter particles, 65-95 % from 0.5-2.5 µm, and 50-60 % from 0.1-0.5 µm, indicating SSA is the dominant contributor to accumulation and coarse-mode aerosol during the winter. The aged SSA particles were characterized by reduced chlorine content with 94 %, by number, internally mixed with secondary sulfate (39 %, by number, internally mixed with both nitrate and sulfate), indicative of multiphase aging reactions during transport. There was a large number fraction (40 % of 1.0-4.0 µm diameter particles) of aged SSA during periods when particles were transported from near Prudhoe Bay, consistent with pollutant emissions from the oil fields participating in atmospheric processing of aerosol particles. Organic carbon and sulfate particles were observed in all samples and comprised 40-50 %, by number, of 0.1-0.4 µm diameter particles, indicative of Arctic haze influence. Soot was internally mixed with organic and sulfate components. All sulfate was mixed with organic carbon or SSA particles. Therefore, aerosol sources in the Alaskan Arctic and resulting aerosol chemical mixing states need to be considered when predicting aerosol climate effects, particularly cloud

  16. Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

    Directory of Open Access Journals (Sweden)

    B. Jing

    2018-04-01

    Full Text Available While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO32 and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA. The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

  17. Understanding the Impact of Model Surfactants on Cloud Condensation Nuclei Activity of Sea Spray Aerosols

    Science.gov (United States)

    Forestieri, S.; Cappa, C. D.; Ruehl, C. R.; Bertram, T. H.; Staudt, S.; Kuborn, T.

    2017-12-01

    Aerosol impacts on cloud properties, also known as indirect effects, remain a major source of uncertainty in modeling global radiative forcing. Reducing this uncertainty necessitates better understanding of how aerosol chemical composition impacts the cloud-forming ability of aerosols. The presence of surfactants in aerosols can decrease the surface tension of activating droplets relative to water and lead to more efficient activation. The importance of this effect has been debated, but recent surface tension measurements of microscopic droplets indicate that surface tension is substantially depressed relative to water for lab-generated particles consisting of salt and a single organic species and for complex mixtures of organic matter. However, little work has been done on understanding how chemical complexity (i.e. interaction between different surfactant species) impacts surface tension for particles containing mixtures of surfactants. In this work, we quantified the surface tension of lab-generated aerosols containing surfactants that are commonly found in nascent sea spray aerosol (SSA) at humidities close to activation using a continuous flow stream-wise thermal gradient chamber (CFSTGC). Surface tension was quantified for particles containing single surfactant species and mixtures of these surfactants to investigate the role of chemical complexity on surface tension and molecular packing at the air-water interface. For all surfactants tested in this study, substantial surface tension depression (20-40 mN/m) relative to water was observed for particles containing large fractions of organic matter at humidities just below activation. However, the presence of these surfactants only weakly depressed surface tension at activation. Kinetic limitations were observed for particles coated with just palmitic acid, since palmitic acid molecules inhibit water uptake through their ability to pack tightly at the surface. However, these kinetic limitations disappeared when

  18. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, W.T.; Walker, B.A. [Environmental Evaluation Group, Albuquerque, NM (United States)

    1997-08-01

    Waste Isolation Pilot Plant (WIPP) alpha continuous air monitor (CAM) performance was evaluated to determine if CAMs could detect accidental releases of transuranic radioactivity from the underground repository. Anomalous alpha spectra and poor background subtraction were observed and attributed to salt deposits on the CAM sampling filters. Microscopic examination of salt laden sampling filters revealed that aerosol particles were forming dendritic structures on the surface of the sampling filters. Alpha CAM detection efficiency decreased exponentially as salt deposits increased on the sampling filters, suggesting that sampling-filter salt was performing like a fibrous filter rather than a membrane filter. Aerosol particles appeared to penetrate the sampling-filter salt deposits and alpha particle energy was reduced. These findings indicate that alpha CAMs may not be able to detect acute releases of radioactivity, and consequently CAMs are not used as part of the WIPP dynamic confinement system. 12 refs., 12 figs., 1 tab.

  19. The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

    2017-06-19

    Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumed that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.

  20. Interannual Variability of the Sea-Ice-Induced Salt Flux in the Greenland Sea

    DEFF Research Database (Denmark)

    Pedersen, Leif Toudal; Coon, M.D.

    2001-01-01

    The Greenland Sea is one of the few places in the World Ocean where deep convection takes place. The convection process is initiated by a density increase originating from rapid cooling and/or a salt flux to the upper layer of the ocean due to brine rejection from ice formation (Rudels, 1990......; Visbeck and others, 1995). The predominant ice types in the Greenland Sea arc frazil/grease ice and pancake ice. A numerical model has been developed relating ice formation and decay of these ice types as observed by the SMMR and SSM/I microwave radiometers and evaluating their contribution to salt...... redistribution in the Greenland Sea. The model has been used to calculate spatial distribution of the annual integrated net salt flux to the Greenland Sea from ice production and advection for the period 1979-97....

  1. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    Science.gov (United States)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 μm). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26

  2. Laser-Induced Breakdown Spectroscopy (LIBS) in a Novel Molten Salt Aerosol System.

    Science.gov (United States)

    Williams, Ammon N; Phongikaroon, Supathorn

    2017-04-01

    In the pyrochemical separation of used nuclear fuel (UNF), fission product, rare earth, and actinide chlorides accumulate in the molten salt electrolyte over time. Measuring this salt composition in near real-time is advantageous for operational efficiency, material accountability, and nuclear safeguards. Laser-induced breakdown spectroscopy (LIBS) has been proposed and demonstrated as a potential analytical approach for molten LiCl-KCl salts. However, all the studies conducted to date have used a static surface approach which can lead to issues with splashing, low repeatability, and poor sample homogeneity. In this initial study, a novel molten salt aerosol approach has been developed and explored to measure the composition of the salt via LIBS. The functionality of the system has been demonstrated as well as a basic optimization of the laser energy and nebulizer gas pressure used. Initial results have shown that this molten salt aerosol-LIBS system has a great potential as an analytical technique for measuring the molten salt electrolyte used in this UNF reprocessing technology.

  3. The Hygroscopicity Parameter of Marine Organics in Sea Spray Aerosols

    Science.gov (United States)

    Boyer, M.; Chang, R. Y. W.

    2015-12-01

    The effects of aerosols on climate are poorly understood, specifically with respect to their influence on cloud properties. Since oceans cover >70% of Earth's surface, sea spray aerosols (SSA), which act efficiently as cloud condensation nuclei (CCN), may have important implications on Earth's radiation budget. Surface active organic species readily accumulate in the sea surface microlayer (SML), located at the ocean-atmosphere interface, and transfer onto nascent SSA. While it is understood that SSA are commonly enriched with organics, the resulting effect of the organic content on CCN activation remains unresolved. The hygroscopicity parameter, kappa (k), allows for the cloud nucleating properties of individual components to be predicted in particles of mixed composition; however, most studies typically infer k from ambient measurements without assessing the contribution of the individual components to the overall k. In this study, a method for quantifying the cloud nucleating properties of the organic species in surface seawater using k-Kohler theory is proposed. Ambient SML and bulk water samples will be collected and atomized to generate particles such that the overall k can be inferred from CCN measurements. The inorganic and organic components will be quantified, and the organic component will be separated so that the hygroscopicity of only the organic constituents can be determined. By comparing the inferred k values for the samples before and after removal of the inorganic component, the hygroscopicity of the organic constituents alone can be calculated, providing insight on the effect of organic species on CCN activation in SSA.

  4. The impact of atmospheric mineral aerosol deposition on the albedo of snow & sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?

    Directory of Open Access Journals (Sweden)

    M. L. Lamare

    2016-01-01

    Full Text Available Knowledge of the albedo of polar regions is crucial for understanding a range of climatic processes that have an impact on a global scale. Light-absorbing impurities in atmospheric aerosols deposited on snow and sea ice by aeolian transport absorb solar radiation, reducing albedo. Here, the effects of five mineral aerosol deposits reducing the albedo of polar snow and sea ice are considered. Calculations employing a coupled atmospheric and snow/sea ice radiative-transfer model (TUV-snow show that the effects of mineral aerosol deposits are strongly dependent on the snow or sea ice type rather than the differences between the aerosol optical characteristics. The change in albedo between five different mineral aerosol deposits with refractive indices varying by a factor of 2 reaches a maximum of 0.0788, whereas the difference between cold polar snow and melting sea ice is 0.8893 for the same mineral loading. Surprisingly, the thickness of a surface layer of snow or sea ice loaded with the same mass ratio of mineral dust has little effect on albedo. On the contrary, the surface albedo of two snowpacks of equal depth, containing the same mineral aerosol mass ratio, is similar, whether the loading is uniformly distributed or concentrated in multiple layers, regardless of their position or spacing. The impact of mineral aerosol deposits is much larger on melting sea ice than on other types of snow and sea ice. Therefore, the higher input of shortwave radiation during the summer melt cycle associated with melting sea ice accelerates the melt process.

  5. Salt in the Air during the Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) Campaign

    Science.gov (United States)

    Pszenny, A.; Keene, W. C.; Sander, R.; Bearekman, R.; Deegan, B.; Maben, J. R.; Warrick-Wriston, C.; Young, A.

    2011-12-01

    Bulk and size-segregated aerosol samples were collected 22 m AGL at the Boulder Atmospheric Observatory (40°N, 105°W, 1563 m ASL) from 18 February to 13 March 2011. Total concentrations of Na, Mg, Al, Cl, V, Mn, Br and I in bulk samples were determined by neutron activation analysis. Ionic composition of all size-segregated and a subset of bulk samples was determined by ion chromatography of aqueous extracts. Mg, Al, V and Mn mass concentrations were highly correlated and present in ratios similar to those in Denver area surface soils. Na and Cl were less well correlated with these soil elements but, after correction for soil contributions, highly correlated with each other. Linear regression of non-soil Cl vs. non-soil Na yielded a slope of 1.69 ± 0.09 (95% C.I.; n = 173), a value between the mass ratios of sea salt (1.80) and halite (1.54). The median Na and Cl concentrations (6.8 and 6.6 nmol m-3 STP, respectively) were factors of 25 to 35 less than those typically measured in the marine boundary layer. Br and I were somewhat correlated and appeared to represent a third aerosol component. The average bulk Cl-:total Cl ratio was 0.99 ± 0.03 (n = 44) suggesting that essentially all aerosol chlorine was water-soluble. Na+ and Cl- mass distributions were bimodal with most of the masses (medians 75% and 78%, respectively, n = 45) in supermicrometer particles. Possible origins of the "salt" component will be discussed based on consideration of 5-day HYSPLIT back trajectories and other information on sampled air mass characteristics.

  6. Radiative Effect of Springtime Biomass-Burning Aerosols over Northern Indochina During 7-SEAS Baseline 2013 Campaign

    Science.gov (United States)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Lee, Chung-Te; Tsay, Si-Chee; Holben, Brent N.; Janjai, Serm; Hsiao, Ta-Chih; Chuang, Ming-Tung; Chantara, Somporn

    2016-01-01

    The direct aerosol radiative effects of biomass-burning (BB) aerosols over northern Indochina were estimated by using aerosol properties (physical, chemical, and optical) along with the vertical profile measurements from ground-based measurements with integration of an optical and a radiative transfer model during the Seven South East Asian Studies Biomass-Burning Aerosols Stratocumulus Environment: Lifecycles Interactions Experiment (7-SEASBASELInE) conducted in spring 2013. Cluster analysis of backward trajectories showed the air masses arriving at mountainous background site (Doi Ang Khang; 19.93degN, 99.05degE, 1536 m above mean sea level) in northern Indochina, mainly from near-source inland BB activities and being confined in the planetary boundary layer. The PM(sub10) and black carbon (BC)mass were 87 +/- 28 and 7 +/- 2 micrograms m(exp -3), respectively. The aerosol optical depth (AOD (sub 500) was found to be 0.26--1.13 (0.71 +/- 0.24). Finer (fine mode fraction is approximately or equal to 0.95, angstrom-exponent at 440-870 nm is approximately or equal to 1.77) and significantly absorbing aerosols(single scattering albedo is approximately or equal to 0.89, asymmetry-parameter is approximately or equal to 0.67, and absorption AOD 0.1 at 440 nm) dominated over this region. BB aerosols (water soluble and BC) were the main contributor to the aerosol radiative forcing (ARF), while others (water insoluble, sea salt and mineral dust) were negligible mainly due to their low extinction efficiency. BC contributed only 6 to the surface aerosol mass but its contribution to AOD was 12 (2 times higher). The overall mean ARF was 8.0 and -31.4 W m(exp -2) at top-of-atmosphere (TOA) and at the surface (SFC), respectively. Likely, ARF due to BC was +10.7 and -18.1 W m(exp -2) at TOA and SFC, respectively. BC imposed the heating rate of +1.4 K d(exp -1) within the atmosphere and highlighting its pivotal role in modifying the radiation budget. We propose that to upgrade our

  7. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    Directory of Open Access Journals (Sweden)

    S. D. Forestieri

    2016-07-01

    Full Text Available The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 % of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs. One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 % values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 % measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer and single particle (using an aerosol time-of-flight mass spectrometer measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 % values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 % depression and the peak chlorophyll a (Chl a concentrations by either 1 (indoor MART or 3-to-6 (outdoor MART days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 % values (relative to pure sea salt is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM comprising the SSA. The GF(85 % values

  8. Inorganic Salt Interference on CO2+ in Aerodyne AMS and ACSM Organic Aerosol Composition Studies.

    Science.gov (United States)

    Pieber, Simone M; El Haddad, Imad; Slowik, Jay G; Canagaratna, Manjula R; Jayne, John T; Platt, Stephen M; Bozzetti, Carlo; Daellenbach, Kaspar R; Fröhlich, Roman; Vlachou, Athanasia; Klein, Felix; Dommen, Josef; Miljevic, Branka; Jiménez, José L; Worsnop, Douglas R; Baltensperger, Urs; Prévôt, André S H

    2016-10-04

    Aerodyne aerosol mass spectrometer (AMS) and Aerodyne aerosol chemical speciation monitor (ACSM) mass spectra are widely used to quantify organic aerosol (OA) elemental composition, oxidation state, and major environmental sources. The OA CO 2 + fragment is among the most important measurements for such analyses. Here, we show that a non-OA CO 2 + signal can arise from reactions on the particle vaporizer, ion chamber, or both, induced by thermal decomposition products of inorganic salts. In our tests (eight instruments, n = 29), ammonium nitrate (NH 4 NO 3 ) causes a median CO 2 + interference signal of +3.4% relative to nitrate. This interference is highly variable between instruments and with measurement history (percentiles P 10-90 = +0.4 to +10.2%). Other semi-refractory nitrate salts showed 2-10 times enhanced interference compared to that of NH 4 NO 3 , while the ammonium sulfate ((NH 4 ) 2 SO 4 ) induced interference was 3-10 times lower. Propagation of the CO 2 + interference to other ions during standard AMS and ACSM data analysis affects the calculated OA mass, mass spectra, molecular oxygen-to-carbon ratio (O/C), and f 44 . The resulting bias may be trivial for most ambient data sets but can be significant for aerosol with higher inorganic fractions (>50%), e.g., for low ambient temperatures, or laboratory experiments. The large variation between instruments makes it imperative to regularly quantify this effect on individual AMS and ACSM systems.

  9. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    International Nuclear Information System (INIS)

    Bartlett, W.T.; Walker, B.A.

    1996-01-01

    Alpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area. In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when sampling-filter salt deposits are at normal to high levels. This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection mechanisms are more important than previously thought. The mechanism of sampling-filter particle collection is critical to measurement of acute releases of radioactivity. 41 refs

  10. Wintertime Arctic Ocean sea water properties and primary marine aerosol concentrations

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2012-11-01

    Full Text Available Sea spray aerosols are an important part of the climate system through their direct and indirect effects. Due to the diminishing sea ice, the Arctic Ocean is one of the most rapidly changing sea spray aerosol source areas. However, the influence of these changes on primary particle production is not known.

    In laboratory experiments we examined the influence of Arctic Ocean water temperature, salinity, and oxygen saturation on primary particle concentration characteristics. Sea water temperature was identified as the most important of these parameters. A strong decrease in sea spray aerosol production with increasing water temperature was observed for water temperatures between −1°C and 9°C. Aerosol number concentrations decreased from at least 1400 cm−3 to 350 cm−3. In general, the aerosol number size distribution exhibited a robust shape with one mode close to dry diameter Dp 0.2 μm with approximately 45% of particles at smaller sizes. Changes in sea water temperature did not result in pronounced change of the shape of the aerosol size distribution, only in the magnitude of the concentrations. Our experiments indicate that changes in aerosol emissions are most likely linked to changes of the physical properties of sea water at low temperatures. The observed strong dependence of sea spray aerosol concentrations on sea water temperature, with a large fraction of the emitted particles in the typical cloud condensation nuclei size range, provide strong arguments for a more careful consideration of this effect in climate models.

  11. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    Directory of Open Access Journals (Sweden)

    D. Neumann

    2016-03-01

    Full Text Available Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ modeling system and are compared to European Monitoring and Evaluation Programme (EMEP measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 +  NH4+ and HNO3 +  NO3− and a decrease in NO3− concentrations. However, the overall effect on NH3 +  NH4+ and HNO3 +  NO3− concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is

  12. New tools and paradigms for the analysis of sea spray aerosols by single particle mass spectrometry

    OpenAIRE

    Sultana, Camille M.

    2017-01-01

    Aerosols can influence the chemistry of the atmosphere as well as also impact global climate by directly scattering light and modifying cloud properties. Sea spray aerosols (SSA) are the second most abundant natural aerosol globally and have the potential to strongly influence atmospheric chemistry and scattering of solar radiation in marine regions. In this dissertation, an ATOFMS was utilized to characterize the chemistry of SSA, focusing on describing the mixing state of the population an...

  13. Effects of NO(y) aging on the dehydration dynamics of model sea spray aerosol.

    Science.gov (United States)

    Woods, Ephraim; Heylman, Kevin D; Gibson, Amanda K; Ashwell, Adam P; Rossi, Sean R

    2013-05-23

    The reactions of NO(y) species in the atmosphere with sea spray aerosol replace halogen anions with nitrate. These experiments show the effect of increasing the nitrate content of model sea spray aerosol particles on the morphology changes and the phase transitions driven by changes in relative humidity (RH). The components of the model particles include H2O, Na+, Mg2+, Cl-, NO3-, and SO4(2-). Tandem differential mobility analyzer (TDMA) measurements yield the water content and efflorescence relative humidity (ERH) of these particles, and probe molecule spectroscopic measurements reveal subsequent phase transitions and partially characterize the salt composition on the surface of dry particles. The results show three effects of increasing the nitrate composition: decreasing the EFH (46 to 29%), production of a metastable aqueous layer on the surface of effloresced particles, and decreasing the sulfate content near the surface of dry particles. For the mixtures studied here, the initial crystallization event forms a core of NaCl. For particles that contain a substantial metastable aqueous layer following efflorescence, probe molecule spectroscopy shows a second crystallization at a lower RH. This subsequent phase transition is likely the formation of Na2SO4. Homogeneous nucleation theory (HNT) using a semiempirical formulation predicts the ERH of all mixtures within 2.0% RH, with a mean absolute deviation of 1.0%. The calculations suggest that structures associated with highly concentrated or supersaturated magnesium ions strongly affect the interfacial tension between the NaCl crystal nucleus and the droplet from which it forms.

  14. Meteorological and Land Surface Properties Impacting Sea Breeze Extent and Aerosol Distribution in a Dry Environment

    Science.gov (United States)

    Igel, Adele L.; van den Heever, Susan C.; Johnson, Jill S.

    2018-01-01

    The properties of sea breeze circulations are influenced by a variety of meteorological and geophysical factors that interact with one another. These circulations can redistribute aerosol particles and pollution and therefore can play an important role in local air quality, as well as impact remote sensing. In this study, we select 11 factors that have the potential to impact either the sea breeze circulation properties and/or the spatial distribution of aerosols. Simulations are run to identify which of the 11 factors have the largest influence on the sea breeze properties and aerosol concentrations and to subsequently understand the mean response of these variables to the selected factors. All simulations are designed to be representative of conditions in coastal sub tropical environments and are thus relatively dry, as such they do not support deep convection associated with the sea breeze front. For this dry sea breeze regime, we find that the background wind speed was the most influential factor for the sea breeze propagation, with the soil saturation fraction also being important. For the spatial aerosol distribution, the most important factors were the soil moisture, sea-air temperature difference, and the initial boundary layer height. The importance of these factors seems to be strongly tied to the development of the surface-based mixed layer both ahead of and behind the sea breeze front. This study highlights potential avenues for further research regarding sea breeze dynamics and the impact of sea breeze circulations on pollution dispersion and remote sensing algorithms.

  15. Large-Scale Covariability Between Aerosol and Precipitation Over the 7-SEAS Region: Observations and Simulations

    Science.gov (United States)

    Huang, Jingfeng; Hsu, N. Christina; Tsay, Si-Chee; Zhang, Chidong; Jeong, Myeong Jae; Gautam, Ritesh; Bettenhausen, Corey; Sayer, Andrew M.; Hansell, Richard A.; Liu, Xiaohong; hide

    2012-01-01

    One of the seven scientific areas of interests of the 7-SEAS field campaign is to evaluate the impact of aerosol on cloud and precipitation (http://7-seas.gsfc.nasa.gov). However, large-scale covariability between aerosol, cloud and precipitation is complicated not only by ambient environment and a variety of aerosol effects, but also by effects from rain washout and climate factors. This study characterizes large-scale aerosol-cloud-precipitation covariability through synergy of long-term multi ]sensor satellite observations with model simulations over the 7-SEAS region [10S-30N, 95E-130E]. Results show that climate factors such as ENSO significantly modulate aerosol and precipitation over the region simultaneously. After removal of climate factor effects, aerosol and precipitation are significantly anti-correlated over the southern part of the region, where high aerosols loading is associated with overall reduced total precipitation with intensified rain rates and decreased rain frequency, decreased tropospheric latent heating, suppressed cloud top height and increased outgoing longwave radiation, enhanced clear-sky shortwave TOA flux but reduced all-sky shortwave TOA flux in deep convective regimes; but such covariability becomes less notable over the northern counterpart of the region where low ]level stratus are found. Using CO as a proxy of biomass burning aerosols to minimize the washout effect, large-scale covariability between CO and precipitation was also investigated and similar large-scale covariability observed. Model simulations with NCAR CAM5 were found to show similar effects to observations in the spatio-temporal patterns. Results from both observations and simulations are valuable for improving our understanding of this region's meteorological system and the roles of aerosol within it. Key words: aerosol; precipitation; large-scale covariability; aerosol effects; washout; climate factors; 7- SEAS; CO; CAM5

  16. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

    Science.gov (United States)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2015-10-01

    The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and

  17. Marine Emissions and Atmospheric Processing Influence Aerosol Mixing States in the Bering Strait and Chukchi Sea

    Science.gov (United States)

    Kirpes, R.; Rodriguez, B.; Kim, S.; Park, K.; China, S.; Laskin, A.; Pratt, K.

    2017-12-01

    The Arctic region is rapidly changing due to sea ice loss and increasing oil/gas development and shipping activity. These changes influence aerosol sources and composition, resulting in complex aerosol-cloud-climate feedbacks. Atmospheric particles were collected aboard the R/V Araon in July-August 2016 in the Alaskan Arctic along the Bering Strait and Chukchi Sea. Offline analysis of individual particles by microscopic and spectroscopic techniques provided information on particle size, morphology, and chemical composition. Sea spray aerosol (SSA) and organic aerosol (OA) particles were the most commonly observed particle types, and sulfate was internally mixed with both SSA and OA. Evidence of multiphase sea spray aerosol reactions was observed, with varying degrees of chlorine depletion observed along the cruise. Notably, atmospherically processed SSA, completely depleted in chlorine, and internally mixed organic and sulfate particles, were observed in samples influenced by the central Arctic Ocean. Changes in particle composition due to fog processing were also investigated. Due to the changing aerosol sources and atmospheric processes in the Arctic region, it is crucial to understand aerosol composition in order to predict climate impacts.

  18. Continuous Flow Hygroscopicity-Resolved Relaxed Eddy Accumulation (Hy-Res REA) Method of Measuring Size-Resolved Sea-Salt Particle Fluxes

    Science.gov (United States)

    Meskhidze, N.; Royalty, T. M.; Phillips, B.; Dawson, K. W.; Petters, M. D.; Reed, R.; Weinstein, J.; Hook, D.; Wiener, R.

    2017-12-01

    The accurate representation of aerosols in climate models requires direct ambient measurement of the size- and composition-dependent particle production fluxes. Here we present the design, testing, and analysis of data collected through the first instrument capable of measuring hygroscopicity-based, size-resolved particle fluxes using a continuous-flow Hygroscopicity-Resolved Relaxed Eddy Accumulation (Hy-Res REA) technique. The different components of the instrument were extensively tested inside the US Environmental Protection Agency's Aerosol Test Facility for sea-salt and ammoniums sulfate particle fluxes. The new REA system design does not require particle accumulation, therefore avoids the diffusional wall losses associated with long residence times of particles inside the air collectors of the traditional REA devices. The Hy-Res REA system used in this study includes a 3-D sonic anemometer, two fast-response solenoid valves, two Condensation Particle Counters (CPCs), a Scanning Mobility Particle Sizer (SMPS), and a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA). A linear relationship was found between the sea-salt particle fluxes measured by eddy covariance and REA techniques, with comparable theoretical (0.34) and measured (0.39) proportionality constants. The sea-salt particle detection limit of the Hy-Res REA flux system is estimated to be 6x105 m-2s-1. For the conditions of ammonium sulfate and sea-salt particles of comparable source strength and location, the continuous-flow Hy-Res REA instrument was able to achieve better than 90% accuracy of measuring the sea-salt particle fluxes. In principle, the instrument can be applied to measure fluxes of particles of variable size and distinct hygroscopic properties (i.e., mineral dust, black carbon, etc.).

  19. New Aerosol Models for the Retrieval of Aerosol Optical Thickness and Normalized Water-Leaving Radiances from the SeaWiFS and MODIS Sensors Over Coastal Regions and Open Oceans

    Science.gov (United States)

    Ahmad, Ziauddin; Franz, Bryan A.; McClain, Charles R.; Kwiatkowska, Ewa J.; Werdell, Jeremy; Shettle, Eric P.; Holben, Brent N.

    2010-01-01

    We describe the development of a new suite of aerosol models for the retrieval of atmospheric and oceanic optical properties from the SeaWiFs and MODIS sensors, including aerosol optical thickness (tau), angstrom coefficient (alpha), and water-leaving radiance (L(sub w)). The new aerosol models are derived from Aerosol Robotic Network (AERONET) observations and have bimodal lognormal distributions that are narrower than previous models used by the Ocean Biology Processing Group. We analyzed AERONET data over open ocean and coastal regions and found that the seasonal variability in the modal radii, particularly in the coastal region, was related to the relative humidity, These findings were incorporated into the models by making the modal radii, as well as the refractive indices, explicitly dependent on relative humidity, From those findings, we constructed a new suite of aerosol models. We considered eight relative humidity values (30%, 50%, 70%, 75%, 80%, 85%, 90%. and 95%) and, for each relative humidity value, we constructed ten distributions by varying the fine-mode fraction from zero to 1. In all. 80 distributions (8Rh x 10 fine-mode fractions) were created to process the satellite data. We. also assumed that the coarse-mode particles were nonabsorbing (sea salt) and that all observed absorptions were entirely due to fine-mode particles. The composition of fine mode was varied to ensure that the new models exhibited the same spectral dependence of single scattering albedo as observed in the AERONET data,

  20. Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    K. Hara

    2013-09-01

    Full Text Available Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica, during the 46th Japanese Antarctic expedition (2005–2006. Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were predominant in the boundary layer and lower free troposphere in summer, whereas sea-salt particles were predominant during winter through spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were predominant during winter through spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42− CH3SO3− and their precursors during summer, and were modified slightly through heterogeneous reactions with NO3− and its precursors. During winter through spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3− and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea ice, Mg-rich sea-salt particles were identified during the months of April through November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles coexisted in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in

  1. An increase in aerosol burden due to the land-sea warming contrast

    Science.gov (United States)

    Hassan, T.; Allen, R.; Randles, C. A.

    2017-12-01

    Climate models simulate an increase in most aerosol species in response to warming, particularly over the tropics and Northern Hemisphere midlatitudes. This increase in aerosol burden is related to a decrease in wet removal, primarily due to reduced large-scale precipitation. Here, we show that the increase in aerosol burden, and the decrease in large-scale precipitation, is related to a robust climate change phenomenon—the land/sea warming contrast. Idealized simulations with two state of the art climate models, the National Center for Atmospheric Research Community Atmosphere Model version 5 (NCAR CAM5) and the Geophysical Fluid Dynamics Laboratory Atmospheric Model 3 (GFDL AM3), show that muting the land-sea warming contrast negates the increase in aerosol burden under warming. This is related to smaller decreases in near-surface relative humidity over land, and in turn, smaller decreases in large-scale precipitation over land—especially in the NH midlatitudes. Furthermore, additional idealized simulations with an enhanced land/sea warming contrast lead to the opposite result—larger decreases in relative humidity over land, larger decreases in large-scale precipitation, and larger increases in aerosol burden. Our results, which relate the increase in aerosol burden to the robust climate projection of enhanced land warming, adds confidence that a warmer world will be associated with a larger aerosol burden.

  2. Fourier transform near-infrared spectroscopy application for sea salt quality evaluation.

    Science.gov (United States)

    Galvis-Sánchez, Andrea C; Lopes, João Almeida; Delgadillo, Ivonne; Rangel, António O S S

    2011-10-26

    Near-infrared (NIR) spectroscopy in diffuse reflectance mode was explored with the objective of discriminating sea salts according to their quality type (traditional salt vs "flower of salt") and geographical origin (Atlantic vs Mediterranean). Sea salts were also analyzed in terms of Ca(2+), Mg(2+), K(+), alkalinity, and sulfate concentrations to support spectroscopic results. High concentrations of Mg(2+) and K(+) characterized Atlantic samples, while a high Ca(2+) content was observed in traditional sea salts. A partial least-squares discriminant analysis model considering the 8500-7500 cm(-1) region permitted the discrimination of salts by quality types. The regions 4650-4350 and 5900-5500 cm(-1) allowed salts classification according to their geographical origin. It was possible to classify correctly 85.3 and 94.8% of the analyzed samples according to the salt type and to the geographical origin, respectively. These results demonstrated that NIR spectroscopy is a suitable and very efficient tool for sea salt quality evaluation.

  3. Sensitivity to deliberate sea salt seeding of marine clouds - observations and model simulations

    OpenAIRE

    Alterskjaer, K.; Kristjansson, J. E.; Seland, O.

    2012-01-01

    Sea salt seeding of marine clouds to increase their albedo is a proposed technique to counteract or slow global warming. In this study, we first investigate the susceptibility of marine clouds to sea salt injections, using observational data of cloud droplet number concentration, cloud optical depth, and liquid cloud fraction from the MODIS (Moderate Resolution Imaging Spectroradiometer) instruments on board the Aqua and Terra satellites. We then compare the derived susceptibility function to...

  4. Speciation of the major inorganic salts in atmospheric aerosols of Beijing, China: Measurements and comparison with model

    Science.gov (United States)

    Tang, Xiong; Zhang, Xiaoshan; Ci, Zhijia; Guo, Jia; Wang, Jiaqi

    2016-05-01

    In the winter and summer of 2013-2014, we used a sampling system, which consists of annular denuder, back-up filter and thermal desorption set-up, to measure the speciation of major inorganic salts in aerosols and the associated trace gases in Beijing. This sampling system can separate volatile ammonium salts (NH4NO3 and NH4Cl) from non-volatile ammonium salts ((NH4)2SO4), as well as the non-volatile nitrate and chloride. The measurement data was used as input of a thermodynamic equilibrium model (ISORROPIA II) to investigate the gas-aerosol equilibrium characteristics. Results show that (NH4)2SO4, NH4NO3 and NH4Cl were the major inorganic salts in aerosols and mainly existed in the fine particles. The sulfate, nitrate and chloride associated with crustal ions were also important in Beijing where mineral dust concentrations were high. About 19% of sulfate in winter and 11% of sulfate in summer were associated with crustal ions and originated from heterogeneous reactions or direct emissions. The non-volatile nitrate contributed about 33% and 15% of nitrate in winter and summer, respectively. Theoretical thermodynamic equilibrium calculations for NH4NO3 and NH4Cl suggest that the gaseous precursors were sufficient to form stable volatile ammonium salts in winter, whereas the internal mixing with sulfate and crustal species were important for the formation of volatile ammonium salts in summer. The results of the thermodynamic equilibrium model reasonably agreed with the measurements of aerosols and gases, but large discrepancy existed in predicting the speciation of inorganic ammonium salts. This indicates that the assumption on crustal species in the model was important for obtaining better understanding on gas-aerosol partitioning and improving the model prediction.

  5. Palmitic Acid on Salt Subphases and in Mixed Monolayers of Cerebrosides: Application to Atmospheric Aerosol Chemistry

    Directory of Open Access Journals (Sweden)

    Ellen M. Adams

    2013-10-01

    Full Text Available Palmitic acid (PA has been found to be a major constituent in marine aerosols, and is commonly used to investigate organic containing atmospheric aerosols, and is therefore used here as a proxy system. Surface pressure-area isotherms (π-A, Brewster angle microscopy (BAM, and vibrational sum frequency generation (VSFG were used to observe a PA monolayer during film compression on subphases of ultrapure water, CaCl2 and MgCl2 aqueous solutions, and artificial seawater (ASW. π-A isotherms indicate that salt subphases alter the phase behavior of PA, and BAM further reveals that a condensation of the monolayer occurs when compared to pure water. VSFG spectra and BAM images show that Mg2+ and Ca2+ induce ordering of the PA acyl chains, and it was determined that the interaction of Mg2+ with the monolayer is weaker than Ca2+. π-A isotherms and BAM were also used to monitor mixed monolayers of PA and cerebroside, a simple glycolipid. Results reveal that PA also has a condensing effect on the cerebroside monolayer. Thermodynamic analysis indicates that attractive interactions between the two components exist; this may be due to hydrogen bonding of the galactose and carbonyl headgroups. BAM images of the collapse structures show that mixed monolayers of PA and cerebroside are miscible at all surface pressures. These results suggest that the surface morphology of organic-coated aerosols is influenced by the chemical composition of the aqueous core and the organic film itself.

  6. Stratigraphic response of salt marshes to slow rates of sea-level change

    Science.gov (United States)

    Daly, J.; Bell, T.

    2006-12-01

    Conventional models of salt-marsh development show an idealized spatial relationship between salt-marsh floral and foraminiferal zones, where the landward margin of the marsh gradually migrates inland in response to sea-level rise. This model predicts that transgression will result in persistent and possibly expanded salt marshes at the surface, depending on a variety of factors including sediment supply, hydrologic conditions, tidal range, and rate of sea-level rise. However, in areas with abundant sediment supply and slow rates of sea- level rise, the extent of back-barrier salt marshes may decline over time as the barrier-spits mature. Sea level around the northeast coast of Newfoundland is rising at a very slow rate during the late Holocene (flora. These transitions are interpreted to reflect the progradation of the spit, decreased tidal exchange in the back-barrier, and increased influence of freshwater streams discharging into the back-barrier setting. Decreased marine influence on the back-barrier environment leads to a floral and faunal shift associated with a regressive stratigraphy in an area experiencing sea-level rise. For studies of Holocene sea-level change requiring salt-marsh stratigraphic records, it is necessary to account for changing micro-environments to locate sites appropriate for study; salt marshes may play an important role in defining the record, but may not exist at the surface to guide investigation.

  7. Effect of sea breeze circulation on aerosol mixing state and radiative properties in a desert setting

    Directory of Open Access Journals (Sweden)

    Y. Derimian

    2017-09-01

    Full Text Available Chemical composition, microphysical, and optical properties of atmospheric aerosol deep inland in the Negev Desert of Israel are found to be influenced by daily occurrences of sea breeze flow from the Mediterranean Sea. Abrupt increases in aerosol volume concentration and shifts of size distributions towards larger sizes, which are associated with increase in wind speed and atmospheric water content, were systematically recorded during the summertime at a distance of at least 80 km from the coast. Chemical imaging of aerosol samples showed an increased contribution of highly hygroscopic particles during the intrusion of the sea breeze. Besides a significant fraction of marine aerosols, the amount of internally mixed marine and mineral dust particles was also increased during the sea breeze period. The number fraction of marine and internally mixed particles during the sea breeze reached up to 88 % in the PM1–2. 5 and up to 62 % in the PM2. 5–10 size range. Additionally, numerous particles with residuals of liquid coating were observed by SEM/EDX analysis. Ca-rich dust particles that had reacted with anthropogenic nitrates were evidenced by Raman microspectroscopy. The resulting hygroscopic particles can deliquesce at very low relative humidity. Our observations suggest that aerosol hygroscopic growth in the Negev Desert is induced by the daily sea breeze arrival. The varying aerosol microphysical and optical characteristics perturb the solar and thermal infrared radiations. The changes in aerosol properties induced by the sea breeze, relative to the background situation, doubled the shortwave radiative cooling at the surface (from −10 to −20.5 W m−2 and increased by almost 3 times the warming of the atmosphere (from 5 to 14 W m−2, as evaluated for a case study. Given the important value of observed liquid coating of particles, we also examined the possible influence of the particle homogeneity assumption on the

  8. Assessment of Aerosol Optical Property and Radiative Effect for the Layer Decoupling Cases over the Northern South China Sea During the 7-SEAS Dongsha Experiment

    Science.gov (United States)

    Pani, Shantau Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-01-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (omega) approx. = 0.92 at 440nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the omega (approx. = 0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6W/sq m2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  9. Assessment of aerosol optical property and radiative effect for the layer decoupling cases over the northern South China Sea during the 7-SEAS/Dongsha Experiment

    Science.gov (United States)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-05-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500 nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the ω (≈0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6 W m-2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  10. Assessment of microphysical and chemical factors of aerosols over seas of the Russian Artic Eastern Section

    Science.gov (United States)

    Golobokova, Liudmila; Polkin, Victor

    2014-05-01

    The newly observed kickoff of the Northern Route development drew serious attention to state of the Arctic Resource environment. Occurring climatic and environmental changes are more sensitively seen in polar areas in particular. Air environment control allows for making prognostic assessments which are required for planning hazardous environmental impacts preventive actions. In August - September 2013, RV «Professor Khlustin» Northern Sea Route expeditionary voyage took place. En-route aerosol sampling was done over the surface of the Beringov, Chukotka and Eastern-Siberia seas (till the town of Pevek). The purpose of sampling was to assess spatio-temporal variability of optic, microphysical and chemical characteristics of aerosol particles of the surface layer within different areas adjacent to the Northern Sea Route. Aerosol test made use of automated mobile unit consisting of photoelectric particles counter AZ-10, aetalometr MDA-02, aspirator on NBM-1.2 pump chassis, and the impactor. This set of equipment allows for doing measurements of number concentration, dispersed composition of aerosols within sizes d=0.3-10 mkm, mass concentration of submicron sized aerosol, and filter-conveyed aerosols sampling. Filter-conveyed aerosols sampling was done using method accepted by EMEP and EANET monitoring networks. The impactor channel was upgraded to separate particles bigger than 1 mkm in size, and the fine grain fraction settled down on it. Reverse 5-day and 10-day trajectories of air mass transfer executed at heights of 10, 1500 and 3500 m were analyzed. The heights were selected by considerations that 3000 m is the height which characterizes air mass trend in the lower troposphere. 1500 m is the upper border of the atmospheric boundary layer, and the sampling was done in the Earth's surface layer at less than 10 m. Minimum values of the bespoken microphysical characteristics are better characteristic of higher latitudes where there are no man induced sources of

  11. SIZE DISTRIBUTION OF SEA-SALT EMISSIONS AS A FUNCTION OF RELATIVE HUMIDITY

    Science.gov (United States)

    This note presents a straightforward method to correct sea-salt-emission particle-size distributions according to local relative humidity. The proposed method covers a wide range of relative humidity (0.45 to 0.99) and its derivation incorporates recent laboratory results on sea-...

  12. Salt marsh persistence is threatened by predicted sea-level rise

    Science.gov (United States)

    Crosby, Sarah C.; Sax, Dov F.; Palmer, Megan E.; Booth, Harriet S.; Deegan, Linda A.; Bertness, Mark D.; Leslie, Heather M.

    2016-11-01

    Salt marshes buffer coastlines and provide critical ecosystem services from storm protection to food provision. Worldwide, these ecosystems are in danger of disappearing if they cannot increase elevation at rates that match sea-level rise. However, the magnitude of loss to be expected is not known. A synthesis of existing records of salt marsh elevation change was conducted in order to consider the likelihood of their future persistence. This analysis indicates that many salt marshes did not keep pace with sea-level rise in the past century and kept pace even less well over the past two decades. Salt marshes experiencing higher local sea-level rise rates were less likely to be keeping pace. These results suggest that sea-level rise will overwhelm most salt marshes' capacity to maintain elevation. Under the most optimistic IPCC emissions pathway, 60% of the salt marshes studied will be gaining elevation at a rate insufficient to keep pace with sea-level rise by 2100. Without mitigation of greenhouse gas emissions this potential loss could exceed 90%, which will have substantial ecological, economic, and human health consequences.

  13. Microphysical and chemical characteristics of near-water aerosol over White and Kara Seas

    Science.gov (United States)

    Terpugova, S. A.; Polkin, V. V.; Panchenko, M. V.; Golobokova, L. P.; Kozlov, V. S.; Shmargunov, V. P.; Shevchenko, V. P.; Lisitzin, A. P.

    2009-04-01

    The results are presented of five-year-long (2003-2007) study of the spatial - temporal variability of the near-water aerosol in the water area of White and Kara Seas (55, 64, 71 and 80-th cruises of RV "Professor Shtockman"; 53 and 54-th cruises of RV "Akademik Mstislav Keldysh"). Measurements of aerosol microphysical characteristics were carried out by means of the automated mobile aerosol complex consisting of nephelometer, photoelectric counter and aethalometer. The aerosol disperse composition was studied with photoelectric counter in 256 size intervals from 0.4 to 10 m. About 1500 series of measurements were carried out in White Sea, and about 1400 series in Kara Sea. Chemical characteristics of aerosol were determined from samples collected on aerosol filters (92 samples were collected in White Sea and 48 in Kara Sea). The ion composition was determined under laboratory conditions. The H+, Na+, K+, Ca2+, Mg2+, NH4+, Cl-, NO3-, HCO3-, SO42- ions were under examination. Comparing aerosol characteristics of two seas, one can note that the mean values of the aerosol content parameters in Kara Sea are less than in White Sea. The ratio of the aerosol mass concentration are from 2 (Yamal Peninsula, northern part of Novaya Zemlya) to 9 times (Blagopoluchia Bay, Ob' Gulf). The differences in the concentration of black carbon vary from 3 (Yamal Peninsula) to 17 times (Blagopoluchia Bay). The differences in the aerosol number concentration NA are not so big. The values NA near Kara Gate, Yamal Peninsula and northern part of Novaya Zemlya are practically the same as in White Sea. The concentration NA at Ob' gulf is one order of magnitude less than in White sea. The obtained aerosol volume size distributions were approximated by the sums of two fractions, submicron and coarse, with lognormal size distributions. The mean volume size distribution of submicron fraction in White Sea is approximated by the distribution with the variance of the radius logarithm s=0.6 and modal

  14. The impact of atmospheric mineral aerosol deposition on the albedo of snow and sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?

    OpenAIRE

    M. L. Lamare; J. Lee-Taylor; M. D. King

    2015-01-01

    Knowledge of the albedo of polar regions is crucial for understanding a range of climatic processes that have an impact on a global scale. Light absorbing impurities in atmospheric aerosols deposited on snow and sea ice by aeolian transport absorb solar radiation, reducing albedo. Here, the effects of five mineral aerosol deposits reducing the albedo of polar snow and sea ice are considered. Calculations employing a coupled atmospheric and snow/sea ice radiative-transfer model (TUV-snow) show...

  15. Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ) model

    OpenAIRE

    J. T. Kelly; P. V. Bhave; C. G. Nolte; U. Shankar; K. M. Foley

    2009-01-01

    Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-salt particles from the coastal surf zone is known to be elevated compared to that from the open ocean. Despite the importance of sea-salt emissions and chemical processing, the US EPA's Community Multiscale Air Quality (C...

  16. Antarctic aerosols - A review

    Science.gov (United States)

    Shaw, Glenn E.

    1988-02-01

    Tropospheric aerosols with the diameter range of half a micron reside in the atmosphere for tens of days and teleconnect Antarctica with other regions by transport that reaches planetary scales of distances; thus, the aerosol on the Antarctic ice represents 'memory modules' of events that took place at regions separated from Antarctica by tens of thousands of kilometers. In terms of aerosol mass, the aerosol species include insoluble crustal products (less than 5 percent), transported sea-salt residues (highly variable but averaging about 10 percent), Ni-rich meteoric material, and anomalously enriched material with an unknown origin. Most (70-90 percent by mass) of the aerosol over the Antarctic ice shield, however, is the 'natural acid sulfate aerosol', apparently deriving from biological processes taking place in the surrounding oceans.

  17. Aerosol properties over the Arabian Sea during the north east monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Dulac, F; Leon, G.F; Desa, E.

    440, 670, 870, 936, 940 and 1020 mm, in the Arabian Sea between 15.4-17.86 degrees N and 73.28-69.3 degrees E, during the North East monsoon period of 1-10 December, 1998. The aerosol optical properties derived from these data showed variations from...

  18. The Dead Sea Mud and Salt: A Review of Its Characterization, Contaminants, and Beneficial Effects

    Science.gov (United States)

    Bawab, Abeer Al; Bozeya, Ayat; Abu-Mallouh, Saida; Abu Irmaileh, Basha'er; Daqour, Ismail; Abu-Zurayk, Rund A.

    2018-02-01

    The Dead Sea has been known for its therapeutic and cosmetic properties. The unique climatic conditions in the Dead Sea area make it a renowned site worldwide for the field of climatotherapy, which is a natural approach for the provision of medications for many human diseases including unusual exclusive salt composition of the water, a special natural mud, thermal mineral springs, solar irradiation, oxygen-rich and bromine-rich haze. This review focuses on the physical, chemical, and biological characteristics of the Dead Sea mud and salts, in addition to their contaminants, allowing this review to serve as a guide to interested researchers to their risks and the importance of treatment. Beneficial effects of Dead Sea mud and salts are discussed in terms of therapy and cosmetics. Additional benefits of both Dead Sea mud and salts are also discussed, such as antimicrobial action of the mud in relation to its therapeutic properties, and the potency of mud and salts to be a good medium for the growth of a halophilic unicellular algae, used for the commercial production of β-carotene Dunaliella.

  19. Aerosol mass loading over the marine environment of Arabian Sea ...

    Indian Academy of Sciences (India)

    The decrease in mass loading from the coast of India towards west is estimated to ... ment of the role of aerosols in radiative forcing ... Oceans are the single largest sources of natural ... While island stations provide informa- ... (Pacific Exploratory Mission), INDOEX (Indian ... very close (150–200km away) to the west Asian.

  20. Quantifying the climatological cloud-free direct radiative forcing of aerosol over the Red Sea

    KAUST Repository

    Brindley, Helen

    2015-04-01

    A combination of ground-based and satellite observations are used, in conjunction with column radiative transfer modelling, to assess the climatological aerosol loading and quantify its corresponding cloud-free direct radiative forcing (DRF) over the Red Sea. While there have been campaigns designed to probe aerosol-climate interactions over much of the world, relatively little attention has been paid to this region. Because of the remoteness of the area, satellite retrievals provide a crucial tool for assessing aerosol loading over the Sea. However, agreement between aerosol properties inferred from measurements from different instruments, and even in some cases from the same measurements using different retrieval algorithms can be poor, particularly in the case of mineral dust. Ground based measurements which can be used to evaluate retrievals are thus highly desirable. Here we take advantage of ship-based sun-photometer micro-tops observations gathered from a series of cruises which took place across the Red Sea during 2011 and 2013. To our knowledge these data represent the first set of detailed aerosol measurements from the Sea. They thus provide a unique opportunity to assess the performance of satellite retrieval algorithms in this region. Initially two aerosol optical depth (AOD) retrieval algorithms developed for the MODerate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are evaluated via comparison with the co-located cruise observations. These show excellent agreement, with correlations typically better than 0.9 and very small root-mean-square and bias differences. Calculations of radiative fluxes and DRF along one of the cruises using the observed aerosol and meteorological conditions also show good agreement with co-located estimates from the Geostationary Earth Radiation Budget (GERB) instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large

  1. EDXRS study of aerosol composition variations in air masses crossing the North Sea

    International Nuclear Information System (INIS)

    Injuk, J.; Malderen, H. van; Grieken, R. van; Swietlicki, E.; Knox, J.M.; Schofield, R.

    1993-01-01

    X-ray emission techniques for bulk and individual particle analysis (EDXRF, EPXMA, micro-PIXE) were combined and applied in atmospheric research on the North Sea area as part of a field-study on air-sea exchange processes of particulate matter. The atmospheric loading for a number of elements was determined by EDXRF, yielding bulk concentrations for Mg, Al, Si, S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br and Sr. From these EDXRF data, deposition rates were derived and, based on a classical multivariate statistical approach, different aerosol sources were identified. Complementary to this work, EPXMA combined with automated image analysis was applied to individual size-segregated aerosol particles to determine their inorganic composition, physical size and shape. Also, the first results of micro-PIXE analyses on individual North Sea aerosol particles, particularly their large-size fraction, are discussed and compared with the corresponding EPXMA results. In summary, such a joint approach with the use of different x-ray emission techniques contributed to the resolution of the mixed structure of the lower North Sea troposphere and to the determination of the atmospheric supply of material to the North Sea environment. (author)

  2. Attachment behavior of fission products to solution aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Takamiya, Koichi; Tanaka, Toru; Nitta, Shinnosuke; Itosu, Satoshi; Sekimoto, Shun; Oki, Yuichi; Ohtsuki, Tsutomu [Research Reactor Institute, Kyoto University, Osaka (Japan)

    2016-12-15

    Various characteristics such as size distribution, chemical component and radioactivity have been analyzed for radioactive aerosols released from Fukushima Daiichi Nuclear Power Plant. Measured results for radioactive aerosols suggest that the potential transport medium for radioactive cesium was non-sea-salt sulfate. This result indicates that cesium isotopes would preferentially attach with sulfate compounds. In the present work the attachment behavior of fission products to aqueous solution aerosols of sodium salts has been studied using a generation system of solution aerosols and spontaneous fission source of {sup 248}Cm. Attachment ratios of fission products to the solution aerosols were compared among the aerosols generated by different solutions of sodium salt. A significant difference according as a solute of solution aerosols was found in the attachment behavior. The present results suggest the existence of chemical effects in the attachment behavior of fission products to solution aerosols.

  3. Estimates of the Spectral Aerosol Single Sea Scattering Albedo and Aerosol Radiative Effects during SAFARI 2000

    Science.gov (United States)

    Bergstrom, Robert W.; Pilewskie, Peter; Schmid, Beat; Russell, Philip B.

    2003-01-01

    Using measurements of the spectral solar radiative flux and optical depth for 2 days (24 August and 6 September 2000) during the SAFARI 2000 intensive field experiment and a detailed radiative transfer model, we estimate the spectral single scattering albedo of the aerosol layer. The single scattering albedo is similar on the 2 days even though the optical depth for the aerosol layer was quite different. The aerosol single scattering albedo was between 0.85 and 0.90 at 350 nm, decreasing to 0.6 in the near infrared. The magnitude and decrease with wavelength of the single scattering albedo are consistent with the absorption properties of small black carbon particles. We estimate the uncertainty in the single scattering albedo due to the uncertainty in the measured fractional absorption and optical depths. The uncertainty in the single scattering albedo is significantly less on the high-optical-depth day (6 September) than on the low-optical-depth day (24 August). On the high-optical-depth day, the uncertainty in the single scattering albedo is 0.02 in the midvisible whereas on the low-optical-depth day the uncertainty is 0.08 in the midvisible. On both days, the uncertainty becomes larger in the near infrared. We compute the radiative effect of the aerosol by comparing calculations with and without the aerosol. The effect at the top of the atmosphere (TOA) is to cool the atmosphere by 13 W/sq m on 24 August and 17 W/sq m on 6 September. The effect on the downward flux at the surface is a reduction of 57 W/sq m on 24 August and 200 W/sq m on 6 September. The aerosol effect on the downward flux at the surface is in good agreement with the results reported from the Indian Ocean Experiment (INDOEX).

  4. Adsorption behavior of radionuclide in water containing sea salts

    International Nuclear Information System (INIS)

    Kani, Yuko; Kamoshida, Mamoru; Asano, Takashi; Tamata, Shin

    2012-01-01

    Waste water caused by the Fukushima Dai-ichi Nuclear Reactor accident contains high level radioactive material with impurities of sea water origin, such as chloride, sodium and magnesium. These impurities have the potential to inhibit the adsorption reaction of radioactive cesium and strontium to adsorbents. We have studied adsorption behavior of radioactive cesium and strontium to adsorbents to measure distribution coefficients (Kd) in the condition of different sea water concentrations. For cesium adsorption, the dependence of Kd on the sea water concentration was affected by the adsorption mechanism of adsorbent; the adsorbents which adsorbed cesium by intercalation showed less dependence of Kd on the sea water concentration, while those adsorbed cesium by ion exchange had smaller Kd with increasing the sea water concentration. For strontium adsorption, Kd decreased as the sea water concentration increased for both adsorbents which adsorbed strontium by intercalation and by ion exchange. The inhibition of intercalation and ion exchange reaction of strontium by calcium ion, that exists high concentration in sea water (400 ppm) and similar hydrated ionic radius with strontium, will cause the decrease of Kd for strontium in the sea water with higher concentration. (author)

  5. Aerosol direct effect on solar radiation over the eastern Mediterranean Sea based on AVHRR satellite measurements

    Science.gov (United States)

    Georgakaki, Paraskevi; Papadimas, Christos D.; Hatzianastassiou, Nikos; Fotiadi, Aggeliki; Matsoukas, Christos; Stackhouse, Paul; Kanakidou, Maria; Vardavas, Ilias M.

    2017-04-01

    Despite the improved scientific understanding of the direct effect of aerosols on solar radiation (direct radiative effect, DRE) improvements are necessary, for example regarding the accuracy of the magnitude of estimated DREs and their spatial and temporal variability. This variability cannot be ensured by in-situ surface and airborne measurements, while it is also relatively difficult to capture through satellite observations. This becomes even more difficult when complete spatial coverage of extended areas is required, especially concerning areas that host various aerosol types with variable physico-chemical and optical aerosol properties. Better assessments of aerosol DREs are necessary, relying on aerosol optical properties with high spatial and temporal variation. The present study aims to provide a refined, along these lines, assessment of aerosol DREs over the eastern Mediterranean (EM) Sea, which is a key area for aerosol studies. Daily DREs are computed for 1˚ x1˚ latitude-longitude grids with the FORTH detailed spectral radiation transfer model (RTM) using input data for various atmospheric and surface parameters, such as clouds, water vapor, ozone and surface albedo, taken from the NASA-Langley Global Earth Observing System (GEOS) database. The model spectral aerosol optical depth (AOD), single scattering albedo and asymmetry parameter are taken from the Global Aerosol Data Set and the NOAA Climate Data Record (CDR) version 2 of Advanced Very High resolution Radiometer (AVHRR) AOD dataset which is available over oceans at 0.63 microns and at 0.1˚ x0.1˚ . The aerosol DREs are computed at the surface, the top-of-atmosphere and within the atmosphere, over the period 1985-1995. Preliminary model results for the period 1990-1993 reveal a significant spatial and temporal variability of DREs over the EM Sea, for example larger values over the Aegean and Black Seas, surrounded by land areas with significant anthropogenic aerosol sources, and over the

  6. Expanding Single Particle Mass Spectrometer Analyses for the Identification of Microbe Signatures in Sea Spray Aerosol.

    Science.gov (United States)

    Sultana, Camille M; Al-Mashat, Hashim; Prather, Kimberly A

    2017-10-03

    Ocean-derived microbes in sea spray aersosol (SSA) have the potential to influence climate and weather by acting as ice nucleating particles in clouds. Single particle mass spectrometers (SPMSs), which generate in situ single particle composition data, are excellent tools for characterizing aerosols under changing environmental conditions as they can provide high temporal resolution and require no sample preparation. While SPMSs have proven capable of detecting microbes, these instruments have never been utilized to definitively identify aerosolized microbes in ambient sea spray aersosol. In this study, an aerosol time-of-flight mass spectrometer was used to analyze laboratory generated SSA produced from natural seawater in a marine aerosol reference tank. We present the first description of a population of biological SSA mass spectra (BioSS), which closely match the ion signatures observed in previous terrestrial microbe studies. The fraction of BioSS dramatically increased in the largest supermicron particles, consistent with field and laboratory measurements of microbes ejected by bubble bursting, further supporting the assignment of BioSS mass spectra as microbes. Finally, as supported by analysis of inorganic ion signals, we propose that dry BioSS particles have heterogeneous structures, with microbes adhered to sodium chloride nodules surrounded by magnesium-enriched coatings. Consistent with this structure, chlorine-containing ion markers were ubiquitous in BioSS spectra and identified as possible tracers for distinguishing recently aerosolized marine from terrestrial microbes.

  7. Salt marsh stability modelled in relation to sea level rise

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart

    2010-01-01

    thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated...... that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt...... marsh base. In general, deeper located markers will indicate successively smaller accretion rates with the same sediment input. Thus, stability analysis made on the basis of newly established marker horizons will be biased and indicate salt marsh stabilities far above the correct level. Running...

  8. Spatial variation of biogenic sulfur in the south Yellow Sea and the East China Sea during summer and its contribution to atmospheric sulfate aerosol.

    Science.gov (United States)

    Zhang, Sheng-Hui; Yang, Gui-Peng; Zhang, Hong-Hai; Yang, Jian

    2014-08-01

    Spatial distributions of biogenic sulfur compounds including dimethylsulfide (DMS), dissolved and particulate dimethylsulfoniopropionate (DMSPd and DMSPp) were investigated in the South Yellow Sea (SYS) and the East China Sea (ECS) in July 2011. The concentrations of DMS and DMSPp were significantly correlated with the levels of chlorophyll a in the surface water. Simultaneously, relatively high ratio values of DMSP/chlorophyll a and DMS/chlorophyll a occurred in the areas where the phytoplankton community was dominated by dinoflagellates. The DMSPp and chlorophyll a size-fractionation showed that larger nanoplankton (5-20 μm) was the most important producer of DMSPp in the study area. The vertical profiles of DMS and DMSP were characterized by a maximum at the upper layer and the bottom concentrations were also relatively higher compared with the overlying layer of the bottom. In addition, a positive linear correlation was observed between dissolved dimethylsulfoxide (DMSOd) and DMS concentrations in the surface waters. The sea-to-air fluxes of DMS in the study area were estimated to be from 0.03 to 102.35 μmol m(-2) d(-1) with a mean of 16.73 μmol m(-2) d(-1) and the contribution of biogenic non-sea-salt SO4(2-) (nss-SO4(2-)) to the measured total nss-SO4(2-) in the atmospheric aerosol over the study area varied from 1.42% to 30.98%, with an average of 8.2%. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Aerosol-driven increase in Arctic sea ice over the middle of the twentieth century

    Science.gov (United States)

    Gagné, Marie-Ève; Fyfe, John C.; Gillett, Nathan P.; Polyakov, Igor V.; Flato, Gregory M.

    2017-07-01

    Updated observational data sets without climatological infilling show that there was an increase in sea ice concentration in the eastern Arctic between 1950 and 1975, contrary to earlier climatology infilled observational data sets that show weak interannual variations during that time period. We here present climate model simulations showing that this observed sea ice concentration increase was primarily a consequence of cooling induced by increasing anthropogenic aerosols and natural forcing. Indeed, sulphur dioxide emissions, which lead to the formation of sulphate aerosols, peaked around 1980 causing a sharp increase in the burden of sulphate between the 1950s and 1970s; but since 1980, the burden has dropped. Our climate model simulations show that the cooling contribution of aerosols offset the warming effect of increasing greenhouse gases over the midtwentieth century resulting in the expansion of the Arctic sea ice cover. These results challenge the perception that Arctic sea ice extent was unperturbed by human influence until the 1970s, suggesting instead that it exhibited earlier forced multidecadal variations, with implications for our understanding of impacts and adaptation in human and natural Arctic systems.

  10. Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

    Directory of Open Access Journals (Sweden)

    D. B. Collins

    2014-11-01

    Full Text Available Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits", a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8–2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic

  11. Micro-Raman and SEM-EDS analyses to evaluate the nature of salt clusters present in secondary marine aerosol.

    Science.gov (United States)

    Morillas, Héctor; Marcaida, Iker; García-Florentino, Cristina; Maguregui, Maite; Arana, Gorka; Madariaga, Juan Manuel

    2018-02-15

    Marine aerosol is a complex inorganic and organic chemistry system which contains several salts, mainly forming different type of salt clusters. Different meteorological parameters have a key role in the formation of these aggregates. The relative humidity (%RH), temperature, CO, SO 2 and NO x levels and even the O 3 levels can promote different chemical reactions giving rise to salt clusters with different morphology and sizes. Sulfates, nitrates and chlorides and even mixed chlorosulfates or nitrosulfates are the final compounds which can be found in environments with a direct influence of marine aerosol. In order to collect and analyze these types of compounds, the use of adequate samplers is crucial. In this work, salt clusters were collected thanks to the use of a self-made passive sampler (SMPS) installed in a 20th century historic building (Punta Begoña Galleries, Getxo, Basque Country, Spain) which is surrounded by a beach and a sportive port. These salt clusters were finally analyzed directly by micro-Raman spectroscopy and Scanning Electron microscopy coupled to Energy Dispersive X-ray spectrometry (SEM-EDS). Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study - Part 2: Philippine receptor observations of fine-scale aerosol behavior

    Science.gov (United States)

    Reid, Jeffrey S.; Lagrosas, Nofel D.; Jonsson, Haflidi H.; Reid, Elizabeth A.; Atwood, Samuel A.; Boyd, Thomas J.; Ghate, Virendra P.; Xian, Peng; Posselt, Derek J.; Simpas, James B.; Uy, Sherdon N.; Zaiger, Kimo; Blake, Donald R.; Bucholtz, Anthony; Campbell, James R.; Chew, Boon Ning; Cliff, Steven S.; Holben, Brent N.; Holz, Robert E.; Hyer, Edward J.; Kreidenweis, Sonia M.; Kuciauskas, Arunas P.; Lolli, Simone; Oo, Min; Perry, Kevin D.; Salinas, Santo V.; Sessions, Walter R.; Smirnov, Alexander; Walker, Annette L.; Wang, Qing; Yu, Liya; Zhang, Jianglong; Zhao, Yongjing

    2016-11-01

    The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August-September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3-12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model

  13. Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study – Part 2: Philippine receptor observations of fine-scale aerosol behavior

    Directory of Open Access Journals (Sweden)

    J. S. Reid

    2016-11-01

    Full Text Available The largest 7 Southeast Asian Studies (7SEAS operations period within the Maritime Continent (MC occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC, and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and

  14. Aerosol Meteorology of Maritime Continent for the 2012 7SEAS Southwest Monsoon Intensive Study - Part 2: Philippine Receptor Observations of Fine-Scale Aerosol Behavior

    Science.gov (United States)

    Reid, Jeffrey S.; Lagrosas, Nofel D.; Jonsson, Haflidi H.; Reid, Elizabeth A.; Atwood, Samuel A.; Boyd, Thomas J.; Ghate, Virendra P.; Xian, Peng; Posselt, Derek J.; Simpas, James B.; hide

    2016-01-01

    The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August-September 2012 biomass burning season. Data included were observations aboard the MY Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 312h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model

  15. Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study – Part 2: Philippine receptor observations of fine-scale aerosol behavior

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Jeffrey S.; Lagrosas, Nofel D.; Jonsson, Haflidi H.; Reid, Elizabeth A.; Atwood, Samuel A.; Boyd, Thomas J.; Ghate, Virendra P.; Xian, Peng; Posselt, Derek J.; Simpas, James B.; Uy, Sherdon N.; Zaiger, Kimo; Blake, Donald R.; Bucholtz, Anthony; Campbell, James R.; Chew, Boon Ning; Cliff, Steven S.; Holben, Brent N.; Holz, Robert E.; Hyer, Edward J.; Kreidenweis, Sonia M.; Kuciauskas, Arunas P.; Lolli, Simone; Oo, Min; Perry, Kevin D.; Salinas, Santo V.; Sessions, Walter R.; Smirnov, Alexander; Walker, Annette L.; Wang, Qing; Yu, Liya; Zhang, Jianglong; Zhao, Yongjing

    2016-01-01

    The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3$-$12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite

  16. Hygroscopic behavior of water-soluble matter in marine aerosols over the East China Sea.

    Science.gov (United States)

    Yan, Yu; Fu, Pingqing; Jing, Bo; Peng, Chao; Boreddy, S K R; Yang, Fan; Wei, Lianfang; Sun, Yele; Wang, Zifa; Ge, Maofa

    2017-02-01

    In this study, we investigated hygroscopic properties of water-soluble matter (WSM) in marine aerosols over the East China Sea, which were collected during a Natural Science Foundation of China (NSFC) sharing cruise in 2014. Hygroscopic growth factors (g) of WSM were measured by a hygroscopicity tandem differential mobility analyzer (H-TDMA) with an initial dry particle mobility diameter of 100nm. The observed g at 90% relative humidity (RH), g(90%) WSM , defined as the ratio of the particle diameter at 90% RH to that at RHsea water was likely due to the transport of anthropogenic aerosols, chemical aging of dust particles, the contribution of biomass burning products, and the aerosol hygroscopic growth inhibition of organics. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Feasibility of laser-induced breakdown spectroscopy (LIBS) for classification of sea salts.

    Science.gov (United States)

    Tan, Man Minh; Cui, Sheng; Yoo, Jonghyun; Han, Song-Hee; Ham, Kyung-Sik; Nam, Sang-Ho; Lee, Yonghoon

    2012-03-01

    We have investigated the feasibility of laser-induced breakdown spectroscopy (LIBS) as a fast, reliable classification tool for sea salts. For 11 kinds of sea salts, potassium (K), magnesium (Mg), calcium (Ca), and aluminum (Al), concentrations were measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the LIBS spectra were recorded in the narrow wavelength region between 760 and 800 nm where K (I), Mg (I), Ca (II), Al (I), and cyanide (CN) band emissions are observed. The ICP-AES measurements revealed that the K, Mg, Ca, and Al concentrations varied significantly with the provenance of each salt. The relative intensities of the K (I), Mg (I), Ca (II), and Al (I) peaks observed in the LIBS spectra are consistent with the results using ICP-AES. The principal component analysis of the LIBS spectra provided the score plot with quite a high degree of clustering. This indicates that classification of sea salts by chemometric analysis of LIBS spectra is very promising. Classification models were developed by partial least squares discriminant analysis (PLS-DA) and evaluated. In addition, the Al (I) peaks enabled us to discriminate between different production methods of the salts. © 2012 Society for Applied Spectroscopy

  18. Dendrochronology of Atriplex portulacoides and Artemisia maritima in Wadden Sea salt marshes

    NARCIS (Netherlands)

    Decuyper, M.; Slim, P.A.; Loon-Steensma, van J.M.

    2014-01-01

    The study uses a rather unusual method, dendrochronology, to investigate the growth and survival of Atriplex portulacoides L. and Artemisia maritima L. on salt marshes at two field sites on the Dutch North Sea barrier islands of Terschelling and Ameland. By providing information on longevity of

  19. Nuclear waste in sea or salt? No, wrong

    International Nuclear Information System (INIS)

    Damveld, H.; Van Duin, S.; Bannink, D.

    1994-04-01

    Eighteen years of successful action against ocean dumping and storage of nuclear waste in salt domes are reviewed for the Dutch situation. The aim of this book is to hand some support to those who want to act against trial borings, in particular the people living close to the most important salt domes in the Netherlands: Ternaard, Zuidwending, Pieterburen, Onstwedde, Winschoten, Schoonlo and Gasselte-Drouwen. In 1976 the Interdepartmental Commission on Nuclear Energy with its subcommission Radioactive Substances (ICK-RAS) was installed, along with a number of working groups, responsible for research. From 1978 onwards ocean dumping operations were accompanied by blockades and legal procedures, which led to a situation of the last dumping in 1982. The Dutch government then focused on nuclear waste storage in salt domes for which the OPLA research program was started. OPLA is the Dutch abbreviation for Storage on Land. The final report (phase 1 and 1a) of OPLA was published on 15 October 1993 as annex to the Dossier Nuclear Energy of the Dutch government. It has been decided that phase 1a is not followed by trial drillings, as planned before. Some critical remarks are made regarding the rounds of public participation and the notion of permanent retrievability of stored nuclear waste. Extensive use has been made of documentation from the Dutch government and parliament, and other literature and information sources

  20. Sensitivity to deliberate sea salt seeding of marine clouds – observations and model simulations

    Directory of Open Access Journals (Sweden)

    K. Alterskjær

    2012-03-01

    Full Text Available Sea salt seeding of marine clouds to increase their albedo is a proposed technique to counteract or slow global warming. In this study, we first investigate the susceptibility of marine clouds to sea salt injections, using observational data of cloud droplet number concentration, cloud optical depth, and liquid cloud fraction from the MODIS (Moderate Resolution Imaging Spectroradiometer instruments on board the Aqua and Terra satellites. We then compare the derived susceptibility function to a corresponding estimate from the Norwegian Earth System Model (NorESM. Results compare well between simulations and observations, showing that stratocumulus regions off the west coast of the major continents along with large regions over the Pacific and the Indian Oceans are susceptible. At low and mid latitudes the signal is dominated by the cloud fraction.

    We then carry out geo-engineering experiments with a uniform increase over ocean of 10−9 kg m−2 s−1 in emissions of sea salt particles with a dry modal radius of 0.13 μm, an emission strength and areal coverage much greater than proposed in earlier studies. The increased sea salt concentrations and the resulting change in marine cloud properties lead to a globally averaged forcing of −4.8 W m−2 at the top of the atmosphere, more than cancelling the forcing associated with a doubling of CO2 concentrations. The forcing is large in areas found to be sensitive by using the susceptibility function, confirming its usefulness as an indicator of where to inject sea salt for maximum effect.

    Results also show that the effectiveness of sea salt seeding is reduced because the injected sea salt provides a large surface area for water vapor and gaseous sulphuric acid to condense on, thereby lowering the maximum supersaturation and suppressing the formation and lifetime of sulphate particles. In some areas, our simulations show an

  1. Satellite retrievals of dust aerosol over the Red Sea and the Persian Gulf (2005-2015)

    Science.gov (United States)

    Banks, Jamie R.; Brindley, Helen E.; Stenchikov, Georgiy; Schepanski, Kerstin

    2017-03-01

    The inter-annual variability of the dust aerosol presence over the Red Sea and the Persian Gulf is analysed over the period 2005-2015. Particular attention is paid to the variation in loading across the Red Sea, which has previously been shown to have a strong, seasonally dependent latitudinal gradient. Over the 11 years considered, the July mean 630 nm aerosol optical depth (AOD) derived from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) varies between 0.48 and 1.45 in the southern half of the Red Sea. In the north, the equivalent variation is between 0.22 and 0.66. The temporal and spatial pattern of variability captured by SEVIRI is also seen in AOD retrievals from the MODerate Imaging Spectroradiometer (MODIS), but there is a systematic offset between the two records. Comparisons of both sets of retrievals with ship- and land-based AERONET measurements show a high degree of correlation with biases of typically only sample relatively low aerosol loadings. When both records are stratified by AOD retrievals from the Multi-angle Imaging SpectroRadiometer (MISR), opposing behaviour is revealed at high MISR AODs ( > 1), with offsets of +0.19 for MODIS and -0.06 for SEVIRI. Similar behaviour is also seen over the Persian Gulf. Analysis of the scattering angles at which retrievals from the SEVIRI and MODIS measurements are typically performed in these regions suggests that assumptions concerning particle sphericity may be responsible for the differences seen.

  2. Plathelminth abundance in North Sea salt marshes: environmental instability causes high diversity

    Science.gov (United States)

    Armonies, Werner

    1986-09-01

    Although supralittoral salt marshes are habitats of high environmental instability, the meiofauna is rich in species and abundance is high. The community structure of free-living Plathelminthes (Turbellaria) in these salt marshes is described. On an average, 104 individuals are found below an area of 10 cm2. The average species density in ungrazed salt marshes is 11.3 below 10 cm2 and 45.2 below 100 cm2, indicating strong small-scale heterogenity. The faunal similarity between sediment and the corresponding above-ground vegetation is higher than between adjacent sample sites. Species prefer distinct ranges of salinity. In the lower part of the supralittoral salt marshes, the annual fluctuations of salinity are strongest and highly unpredictable. This region is richest in plathelminth species and abundance; diversity is highest, and the faunal composition of parallel samples is quite similar. In the upper part of the supralittoral salt marshes, the annual variability of salinity is lower, plathelminths are poor in species diversity and abundance. Parallel samples often have no species in common. Thus, those salt marsh regions with the most unstable environment are inhabited by the most diverse species assemblage. Compared to other littoral zones of the North Sea, however, plathelminth diversity in salt marshes is low. The observed plathelminth diversity pattern can apparently be explained by the “dynamic equilibrium model” (Huston, 1979).

  3. Physical properties of the arctic summer aerosol particles in relation ...

    Indian Academy of Sciences (India)

    The sea-salt particles of marine origin generated within the Arctic circle are identified as the main source of the Arctic summer aerosols. ... concentration starts decreasing within a few minutes from the start of these events but requires a few hours to restore to the normal background aerosol level after the end of event.

  4. Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols

    Science.gov (United States)

    Schmitt-Kopplin, P.; Liger-Belair, G.; Koch, B. P.; Flerus, R.; Kattner, G.; Harir, M.; Kanawati, B.; Lucio, M.; Tziotis, D.; Hertkorn, N.; Gebefügi, I.

    2012-04-01

    Atmospheric aerosols impose direct and indirect effects on the climate system, for example, by absorption of radiation in relation to cloud droplets size, on chemical and organic composition and cloud dynamics. The first step in the formation of Organic primary aerosols, i.e. the transfer of dissolved organic matter from the marine surface into the atmosphere, was studied. We present a molecular level description of this phenomenon using the high resolution analytical tools of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR). Our experiments confirm the chemoselective transfer of natural organic molecules, especially of aliphatic compounds from the surface water into the atmosphere via bubble bursting processes. Transfer from marine surface water to the atmosphere involves a chemical gradient governed by the physicochemical properties of the involved molecules when comparing elemental compositions and differentiating CHO, CHNO, CHOS and CHNOS bearing compounds. Typical chemical fingerprints of compounds enriched in the aerosol phase were CHO and CHOS molecular series, smaller molecules of higher aliphaticity and lower oxygen content, and typical surfactants. A non-targeted metabolomics analysis demonstrated that many of these molecules corresponded to homologous series of oxo-, hydroxy-, methoxy-, branched fatty acids and mono-, di- and tricarboxylic acids as well as monoterpenes and sugars. These surface active biomolecules were preferentially transferred from surface water into the atmosphere via bubble bursting processes to form a significant fraction of primary organic aerosols. This way of sea spray production leaves a selective biological signature of the surface water in the corresponding aerosol that may be transported into higher altitudes up to the lower atmosphere, thus contributing to the formation of secondary organic aerosol on a global scale or transported laterally with

  5. Single-particle investigation of summertime and wintertime Antarctic sea spray aerosols using low-Z particle EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques

    Science.gov (United States)

    Eom, Hyo-Jin; Gupta, Dhrubajyoti; Cho, Hye-Rin; Hwang, Hee Jin; Do Hur, Soon; Gim, Yeontae; Ro, Chul-Un

    2016-11-01

    Two aerosol samples collected at King Sejong Korean scientific research station, Antarctica, on 9 December 2011 in the austral summer (sample S1) and 23 July 2012 in the austral winter (sample S2), when the oceanic chlorophyll a levels on the collection days of the samples were quite different, by ˜ 19 times (2.46 vs. 0.13 µg L-1, respectively), were investigated on a single-particle basis using quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), called low-Z particle EPMA, Raman microspectrometry (RMS), and attenuated total reflection Fourier transform infrared (ATR-FTIR) imaging techniques to obtain their characteristics based on the elemental chemical compositions, molecular species, and mixing state. X-ray analysis showed that the supermicron summertime and wintertime Antarctic aerosol samples have different elemental chemical compositions, even though all the individual particles analyzed were sea spray aerosols (SSAs); i.e., the contents of C, O, Ca, S, and Si were more elevated, whereas Cl was more depleted, for sample S1 than for sample S2. Based on qualitative analysis of the chemical species present in individual SSAs by the combined application of RMS and ATR-FTIR imaging, different organic species were observed in samples S1 and S2; i.e., Mg hydrate salts of alanine were predominant in samples S1 and S2, whereas Mg salts of fatty acids internally mixed with Mg hydrate salts of alanine were significant in sample S2. Although CaSO4 was observed significantly in both samples S1 and S2, other inorganic species, such as Na2SO4, NaNO3, Mg(NO3)2, SiO2, and CH3SO3Mg, were observed more significantly in sample S1, suggesting that those compounds may be related to the higher phytoplankton activity in summer.

  6. The European aerosol budget in 2006

    Directory of Open Access Journals (Sweden)

    J. M. J. Aan de Brugh

    2011-02-01

    Full Text Available This paper presents the aerosol budget over Europe in 2006 calculated with the global transport model TM5 coupled to the size-resolved aerosol module M7. Comparison with ground observations indicates that the model reproduces the observed concentrations quite well with an expected slight underestimation of PM10 due to missing emissions (e.g. resuspension. We model that a little less than half of the anthropogenic aerosols emitted in Europe are exported and the rest is removed by deposition. The anthropogenic aerosols are removed mostly by rain (95% and only 5% is removed by dry deposition. For the larger natural aerosols, especially sea salt, a larger fraction is removed by dry processes (sea salt: 70%, mineral dust: 35%. We model transport of aerosols in the jet stream in the higher atmosphere and an import of Sahara dust from the south at high altitudes. Comparison with optical measurements shows that the model reproduces the Ångström parameter very well, which indicates a correct simulation of the aerosol size distribution. However, we underestimate the aerosol optical depth. Because the surface concentrations are close to the observations, the shortage of aerosol in the model is probably at higher altitudes. We show that the discrepancies are mainly caused by an overestimation of wet-removal rates. To match the observations, the wet-removal rates have to be scaled down by a factor of about 5. In that case the modelled ground-level concentrations of sulphate and sea salt increase by 50% (which deteriorates the match, while other components stay roughly the same. Finally, it is shown that in particular events, improved fire emission estimates may significantly improve the ability of the model to simulate the aerosol optical depth. We stress that discrepancies in aerosol models can be adequately analysed if all models would provide (regional aerosol budgets, as presented in the current study.

  7. Impact of springtime biomass-burning aerosols on radiative forcing over northern Thailand during the 7SEAS campaign

    Science.gov (United States)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Lee, Chung-Te; Tsay, Si-Chee; Holben, Brent; Janjai, Serm; Hsiao, Ta-Chih; Chuang, Ming-Tung; Chantara, Somporn

    2016-04-01

    Biomass-burning (BB) aerosols are the significant contributor to the regional/global aerosol loading and radiation budgets. BB aerosols affect the radiation budget of the earth and atmosphere by scattering and absorbing directly the incoming solar and outgoing terrestrial radiation. These aerosols can exert either cooling or warming effect on climate, depending on the balance between scattering and absorption. BB activities in the form of wildland forest fires and agricultural crop burning are very pronounced in the Indochina peninsular regions in Southeast Asia mainly in spring (late February to April) season. The region of interest includes Doi Ang Khang (19.93° N, 99.05° E, 1536 msl) in northern Thailand, as part of the Seven South East Asian Studies (7-SEAS)/BASELInE (Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interactions Experiment) campaign in 2013. In this study, for the first time, the direct aerosol radiative effects of BB aerosols over near-source BB emissions, during the peak loading spring season, in northern Indochina were investigated by using ground-based physical, chemical, and optical properties of aerosols as well as the aerosol optical and radiative transfer models. Information on aerosol parameters in the field campaign was used in the OPAC (Optical Properties of Aerosols and Clouds) model to estimate various optical properties corresponding to aerosol compositions. Clear-sky shortwave direct aerosol radiative effects were further estimated with a raditive transfer model SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer). The columnar aerosol optical depth (AOD500) was found to be ranged from 0.26 to 1.13 (with the mean value 0.71 ± 0.24). Fine-mode (fine mode fraction ≈0.98, angstrom exponent ≈1.8) and significantly absorbing aerosols (columnar single-scattering albedo ≈0.89, asymmetry-parameter ≈0.67 at 441 nm wavelength) dominated in this region. Water soluble and black carbon (BC) aerosols mainly

  8. Trace elements in the sea surface microlayer: rapid responses to changes in aerosol deposition

    Directory of Open Access Journals (Sweden)

    Alina M. Ebling

    2017-08-01

    Full Text Available Natural and anthropogenic aerosols are a significant source of trace elements to oligotrophic ocean surface waters, where they provide episodic pulses of limiting micronutrients for the microbial community. However, little is known about the fate of trace elements at the air-sea interface, i.e. the sea surface microlayer. In this study, samples of aerosols, sea surface microlayer, and underlying water column were collected in the Florida Keys during a dusty season (July 2014 and non-dusty season (May 2015 and analyzed for the dissolved and particulate elements Al, Fe, Ni, Cu, Zn, and Pb. Microlayer samples were collected using a cylinder of ultra-pure SiO2 (quartz glass, a novel adaptation of the glass plate technique. A significant dust deposition event occurred during the 2014 sampling period which resulted in elevated concentrations of trace elements in the microlayer. Residence times in the microlayer from this event ranged from 12 to 94 minutes for dissolved trace elements and from 1.3 to 3.4 minutes for particulate trace elements. These residence times are potentially long enough for the atmospherically derived trace elements to undergo chemical and biological alterations within the microlayer. Characterizing the trace element distributions within the three regimes is an important step towards our overall goals of understanding the rates and mechanisms of the solubilization of trace elements following aeolian dust deposition and how this might affect microorganisms in surface waters.

  9. Analysis of Organic Anionic Surfactants in Fine and Coarse Fractions of Freshly Emitted Sea Spray Aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, Richard E.; Laskina, Olga; Jayarathne, Thilina; Laskin, Alexander; Laskin, Julia; Lin, Peng; Sultana, Camile M.; Lee, Christopher; Moore, Kathryn A.; Cappa, Christopher; Bertram, Timothy; Prather, Kimberly; Grassian, Vicki H.; Stone, Elizabeth

    2016-02-01

    The inclusion of organic compounds in freshly emitted sea spray aerosol (SSA) has been shown to be size-dependent, with an increasing organic fraction in smaller particles. Defining the molecular composition of sea spray aerosol has proven challenging, due to the mix of continental and background particles even in remote marine environments. Here we have used electrospray ionization-high resolution mass spectrometry in negative ion mode to identify organic compounds in nascent sea spray collected throughout a 25-day mesocosm experiment. Over 280 organic compounds from ten major homologous series were identified. These compounds were operationally defined as molecules containing a hydrophobic alkyl chain with a hydrophilic head group making them surface active. The most abundant class of molecules detected were saturated (C8–C24) and unsaturated (C12–C22) fatty acids. Fatty acid derivatives (including saturated oxo-fatty acids (C5–C18) and saturated hydroxy-fatty acids (C5–C18) were also identified. Interestingly, anthropogenic influences on SSA from the seawater were observed in the form of sulfate (C2–C7, C12–C17) and sulfonate (C16–C22) species. During the mesocosm, the distributions of molecules within each homologous series were observed to respond to variations among the levels of phytoplankton and bacteria in the seawater, indicating an important role of biological processes in determining the composition of SSA.

  10. Evaluation of Long-term Aerosol Data Records from SeaWiFS over Land and Ocean

    Science.gov (United States)

    Bettenhausen, C.; Hsu, C.; Jeong, M.; Huang, J.

    2010-12-01

    Deserts around the globe produce mineral dust aerosols that may then be transported over cities, across continents, or even oceans. These aerosols affect the Earth’s energy balance through direct and indirect interactions with incoming solar radiation. They also have a biogeochemical effect as they deliver scarce nutrients to remote ecosystems. Large dust storms regularly disrupt air traffic and are a general nuisance to those living in transport regions. In the past, measuring dust aerosols has been incomplete at best. Satellite retrieval algorithms were limited to oceans or vegetated surfaces and typically neglected desert regions due to their high surface reflectivity in the mid-visible and near-infrared wavelengths, which have been typically used for aerosol retrievals. The Deep Blue aerosol retrieval algorithm was developed to resolve these shortcomings by utilizing the blue channels from instruments such as the Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) to infer aerosol properties over these highly reflective surfaces. The surface reflectivity of desert regions is much lower in the blue channels and thus it is easier to separate the aerosol and surface signals than at the longer wavelengths used in other algorithms. More recently, the Deep Blue algorithm has been expanded to retrieve over vegetated surfaces and oceans as well. A single algorithm can now follow dust from source to sink. In this work, we introduce the SeaWiFS instrument and the Deep Blue aerosol retrieval algorithm. We have produced global aerosol data records over land and ocean from 1997 through 2009 using the Deep Blue algorithm and SeaWiFS data. We describe these data records and validate them with data from the Aerosol Robotic Network (AERONET). We also show the relative performance compared to the current MODIS Deep Blue operational aerosol data in desert regions. The current results are encouraging and this dataset will

  11. Satellite retrievals of dust aerosol over the Red Sea and the Persian Gulf (2005–2015)

    KAUST Repository

    Banks, Jamie R.

    2017-07-13

    The inter-annual variability of the dust aerosol presence over the Red Sea and the Persian Gulf is analysed over the period 2005-2015. Particular attention is paid to the variation in loading across the Red Sea, which has previously been shown to have a strong, seasonally dependent latitudinal gradient. Over the 11 years considered, the July mean 630 nm aerosol optical depth (AOD) derived from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) varies between 0.48 and 1.45 in the southern half of the Red Sea. In the north, the equivalent variation is between 0.22 and 0.66. The temporal and spatial pattern of variability captured by SEVIRI is also seen in AOD retrievals from the MODerate Imaging Spectroradiometer (MODIS), but there is a systematic offset between the two records. Comparisons of both sets of retrievals with ship-and land-based AERONET measurements show a high degree of correlation with biases of < 0.08. However, these comparisons typically only sample relatively low aerosol loadings. When both records are stratified by AOD retrievals from the Multi-angle Imaging SpectroRadiometer (MISR), opposing behaviour is revealed at high MISR AODs (> 1), with offsets of C 0.19 for MODIS and 0.06 for SEVIRI. Similar behaviour is also seen over the Persian Gulf. Analysis of the scattering angles at which retrievals from the SEVIRI and MODIS measurements are typically performed in these regions suggests that assumptions concerning particle sphericity may be responsible for the differences seen.

  12. Improving Satellite Retrieved Infrared Sea Surface Temperatures in Aerosol-Contaminated Regions

    Science.gov (United States)

    Luo, B.; Minnett, P. J.; Szczodrak, G.; Kilpatrick, K. A.

    2017-12-01

    Infrared satellite observations of sea surface temperature (SST) have become essential for many applications in meteorology, climatology, and oceanography. Applications often require high accuracy SST data: for climate research and monitoring an absolute uncertainty of 0.1K and stability of better than 0.04K per decade are required. Tropospheric aerosol concentrations increase infrared signal attenuation and prevent the retrieval of accurate satellite SST. We compare satellite-derived skin SST with measurements from the Marine-Atmospheric Emitted Radiance Interferometer (M-AERI) deployed on ships during the Aerosols and Ocean Science Expeditions (AEROSE) and with quality-controlled drifter temperatures. After match-up with in-situ SST and filtering of cloud contaminated data, the results indicate that SST retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) aboard the Terra and Aqua satellites have negative (cool) biases compared to shipboard radiometric measurements. There is also a pronounced negative bias in the Saharan outflow area that can introduce SST errors >1 K at aerosol optical depths > 0.5. In this study, we present a new method to derive night-time Saharan Dust Index (SDI) algorithms based on simulated brightness temperatures at infrared wavelengths of 3.9, 10.8 and 12.0 μm, derived using RTTOV. We derived correction coefficients for Aqua MODIS measurements by regression of the SST errors against the SDI. The biases and standard deviations are reduced by 0.25K and 0.19K after the SDI correction. The goal of this study is to understand better the characteristics and physical mechanisms of aerosol effects on satellite retrieved infrared SST, as well as to derive empirical formulae for improved accuracies in aerosol-contaminated regions.

  13. Retrieval of spectral aerosol optical thickness over land using ocean color sensors MERIS and SeaWiFS

    Directory of Open Access Journals (Sweden)

    W. von Hoyningen-Huene

    2011-02-01

    Full Text Available For the determination of aerosol optical thickness (AOT Bremen AErosol Retrieval (BAER has been developed. Method and main features on the aerosol retrieval are described together with validation and results. The retrieval separates the spectral aerosol reflectance from surface and Rayleigh path reflectance for the shortwave range of the measured spectrum of top-of-atmosphere reflectance for wavelength less than 0.670 μm. The advantage of MERIS (Medium Resolution Imaging Spectrometer on the Environmental Satellite – ENVISAT – of the European Space Agency – ESA and SeaWiFS (Sea viewing Wide Field Sensor on OrbView-2 spacecraft observations is the availability of several spectral channels in the blue and visible range enabling the spectral determination of AOT in 7 (or 6 channels (0.412–0.670 μm and additionally channels in the NIR, which can be used to characterize the surface properties. A dynamical spectral surface reflectance model for different surface types is used to obtain the spectral surface reflectance for this separation. The normalized differential vegetation index (NDVI, taken from the satellite observations, is the model input. Further surface bi-directional reflectance distribution function (BRDF is considered by the Raman-Pinty-Verstraete (RPV model. Spectral AOT is obtained from aerosol reflectance using look-up-tables, obtained from radiative transfer calculations with given aerosol phase functions and single scattering albedos either from aerosol models, given by model package "optical properties of aerosol components" (OPAC or from experimental campaigns. Validations of the obtained AOT retrieval results with data of Aerosol Robotic Network (AERONET over Europe gave a preference for experimental phase functions derived from almucantar measurements. Finally long-term observations of SeaWiFS have been investigated for 11 year trends in AOT. Western European regions have negative trends with decreasing AOT with time

  14. Wind-Driven Sea-Level Variation Influences Dynamics of Salt Marsh Vegation

    DEFF Research Database (Denmark)

    Kim, Daehyun; Cairns, David; Bartholdy, Jesper

    2011-01-01

    Long-term variation of mean sea level has been considered the primary exogenous factor of vegetation dynamics in salt marshes. In this study, we address the importance of short-term, wind-induced rise of the sea surface in such biogeographic changes. There was an unusual opportunity for examining......, waterlogging of marsh soils, which has retarded ecological succession. To conclude, we stress the need for a multitemporal perspective that recognizes the significance of short-term sea-level fluctuations nested within long-term trends......) continuous sedimentation with spatial variability (2.0–4.0 mm yr-1), (3) increased frequency of over-marsh flooding events, and (4) contemporary dominance of Halimione portulacoides, indicating little progressive succession toward a later phase. Conventionally, recent eustatic sea-level rise was believed...... to drive the increased frequency of flooding and such retarded succession. Skallingen, however, has showed more or less equilibrated yearly rates between sea-level rise and surface accretion. This implies that the long-term, gradual sea-level rise alone might not be enough to explain the increased...

  15. Disentangling sea-surface temperature and anthropogenic aerosol influences on recent trends in South Asian monsoon rainfall

    Science.gov (United States)

    Patil, Nitin; Venkataraman, Chandra; Muduchuru, Kaushik; Ghosh, Subimal; Mondal, Arpita

    2018-05-01

    Recent studies point to combined effects of changes in regional land-use, anthropogenic aerosol forcing and sea surface temperature (SST) gradient on declining trends in the South Asian monsoon (SAM). This study attempted disentangling the effects produced by changes in SST gradient from those by aerosol levels in an atmospheric general circulation model. Two pairs of transient ensemble simulations were made, for a 40-year period from 1971 to 2010, with evolving versus climatological SSTs and with anthropogenic aerosol emissions fixed at 1971 versus 2010, in each case with evolution of the other forcing element, as well as GHGs. Evolving SST was linked to a widespread feedback on increased surface temperature, reduced land-sea thermal contrast and a weakened Hadley circulation, with weakening of cross-equatorial transport of moisture transport towards South Asia. Increases in anthropogenic aerosol levels (1971 versus 2010), led to an intensification of drying in the peninsular Indian region, through several regional pathways. Aerosol forcing induced north-south asymmetries in temperature and sea-level pressure response, and a cyclonic circulation in the Bay of Bengal, leading to an easterly flow, which opposes the monsoon flow, suppressing moisture transport over peninsular India. Further, aerosol induced decreases in convection, vertically integrated moisture flux convergence, evaporation flux and cloud fraction, in the peninsular region, were spatially congruent with reduced convective and stratiform rainfall. Overall, evolution of SST acted through a weakening of cross-equatorial moisture flow, while increases in aerosol levels acted through suppression of Arabian Sea moisture transport, as well as, of convection and vertical moisture transport, to influence the suppression of SAM rainfall.

  16. A sea surface reflectance model for (AATSR, and application to aerosol retrievals

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2010-07-01

    Full Text Available A model of the sea surface bidirectional reflectance distribution function (BRDF is presented for the visible and near-IR channels (over the spectral range 550 nm to 1.6 μm of the dual-viewing Along-Track Scanning Radiometers (ATSRs. The intended application is as part of the Oxford-RAL Aerosols and Clouds (ORAC retrieval scheme. The model accounts for contributions to the observed reflectance from whitecaps, sun-glint and underlight. Uncertainties in the parametrisations used in the BRDF model are propagated through into the forward model and retrieved state. The new BRDF model offers improved coverage over previous methods, as retrievals are possible into the sun-glint region, through the ATSR dual-viewing system. The new model has been applied in the ORAC aerosol retrieval algorithm to process Advanced ATSR (AATSR data from September 2004 over the south-eastern Pacific. The assumed error budget is shown to be generally appropriate, meaning the retrieved states are consistent with the measurements and a priori assumptions. The resulting field of aerosol optical depth (AOD is compared with colocated MODIS-Terra observations, AERONET observations at Tahiti, and cruises over the oceanic region. MODIS and AATSR show similar spatial distributions of AOD, although MODIS reports values which are larger and more variable. It is suggested that assumptions in the MODIS aerosol retrieval algorithm may lead to a positive bias in MODIS AOD of order 0.01 at 550 nm over ocean regions where the wind speed is high.

  17. Aerosol Radiative Impact on the Middle East Regional Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2017-10-01

    The climate in the Middle East is complex and remains poorly understood. Due to the vast Arabian Desert, it is very sensitive to radiative forcing. Mineral dust is the dominant aerosol in this region. High background dust loading and frequent dust outbreaks significantly perturb the radiative balance and contribute to climate variability in the Middle East. To assess the climatological impact of dust in the region, we derived the aerosol optical properties and used a standalone column model to quantify radiative forcing sensitivity to a range of parameters representative of the Arabian Peninsula and the Red Sea. Simulations and modeling assumptions were validated using available in situ observations and satellite retrievals for fair weather and dust storm conditions. We incorporated the optical properties into the regional coupled ocean-atmosphere model and conducted simulations that represent the regional climate. The analysis shows that dust cools the Earth-atmosphere system and thus offsets the warming due to greenhouse gases. Dust reduces the sea surface temperature by 0.4 K, significantly perturbs energy balance, overturning circulation, and its purely dynamical impact reduces biological productivity in the Red Sea. In the real world, dust is present permanently and this does not allow to directly observe the climate response to the dust forcing. Volcanic eruptions produce a transient radiative impact that causes a detectable climate response that could be evaluated from observations and compared with simulations. Large equatorial eruptions are known to significantly perturb the Earth’s climate on the global scale, but their regional impact on the Middle East has not been thoroughly investigated. For example, the 1991 Mount Pinatubo eruption had a profound effect on the MENA and caused extensive coral bleaching in the Gulf of Aqaba. The analysis shows that observed cooling in the Middle East was mostly driven by changes in the atmospheric large

  18. Seasonal variations of sulfate, carbonaceous species (black carbon and polycyclic aromatic hydrocarbons), and trace elements in fine atmospheric aerosols collected at subtropical islands in the East China Sea

    Science.gov (United States)

    Kaneyasu, Naoki; Takada, Hideshige

    2004-03-01

    In order to characterize the outflow of pollution derived aerosols from the Asian Pacific rim to the North Pacific Ocean, seasonal variations of fine aerosol components (aerodynamic diameter <2 μm) were collected at two islands (Amami Island and Miyako Island) that surround the East China Sea. Monthly averaged concentrations of non-sea-salt SO42- (nss.SO42-) and black carbon (BC) at Amami and Miyako showed relatively high values in winter to spring and low values in summer. The observed seasonal variation is basically determined by the northwesterly monsoon in winter to spring and southeasterly wind from the stationary North Pacific anticyclone in summer. The minimum concentration levels of nss.SO42- and BC in summer were almost 2-3 times that of the North Pacific background level. Trace metals in aerosols showed similar seasonal variations observed for nss.SO42- and BC. The concentrations of nss.SO42- and Sb were highly correlated; this is in contradiction with the results at stations established in Pacific Exploratory Mission-West ground monitoring sites. Polycyclic aromatic hydrocarbons (PAHs) also showed a pronounced maximum in winter and/or spring, with maximum concentrations comparable in magnitude to those in spring at Barrow, Alaska. Many of the low molecular weight species of PAHs had high correlation with BC, suggesting that they were either transported independently in a similar way or were transported attached to BC. Furthermore, the relative abundance of some PAH species in the present study and those found in deep-ocean surface sediments sampled in the middle Pacific Ocean are compared and discussed.

  19. Uptake Coefficients of NO3 Radicals on Solid Surfaces of Sea-Salts

    Science.gov (United States)

    Gratpanche, F.; Sawerysyn, J.-P.

    1999-02-01

    Uptake coefficients of nitrate radicals (γ NO_3) have been measured by a technique involving a coated-wall flow tube with radical detection by E.P.R. spectrometry. The variation of NO3 concentration in the gas phase was followed indirectly by monitoring OH radicals produced by the titration reaction H + NO_3. The mean initial value of γ NO3 measured on solid NaCl surfaces was (1.7± 1.2)× 10-2) in the temperature range 258-301 K, while for solid NaBr surfaces the value was (0.11 ± 0.06) at 293 K. In each case, errors limits correspond to one standard deviation. For NaBr, a slight negative temperature dependence was observed over the investigated range, 243-293 K, which can be represented by γ_NO_3^NaBr = 1.6 ≤ft(begin{array}{l}+1.8 -0.9) × 10-3exp [(1210± 200)/T]. An analysis of the results shows that under some conditions the heterogeneous loss of nitrate radicals on sea-salt aerosol particles at ambient temperature could be competitive with their loss by homogeneous reaction in the marine troposphere at night. Les coefficients de capture des radicaux nitrate (γ NO_3) sur des surfaces de sels marins (NaCl et NaBr) ont été mesurés aux températures troposphériques en utilisant la technique du réacteur à écoulement à paroi recouverte couplée à un spectromètre de résonance paramagnétique électronique (R.P.E). La variation de la concentration en phase gazeuse des radicaux nitrate en présence des surfaces étudiées est suivie en mesurant le signal R.P.E des radicaux OH produits par la réaction de titrage H + NO3. Pour des températures comprises entre 258 et 301 K, la valeur moyenne du coefficient de capture initial (γ NO_3) sur des surfaces solides de NaCl est égal à (1.7± 1.2)× 10-2). Sur des surfaces solides de NaBr, (γ NO_3) est égal à (0.11 ± 0.06) à 293 K. L'incertitude correspond à une déviation standard. Par ailleurs, pour ce type de surfaces, une légère dépendance négative avec la température est observée dans la

  20. Influence of continental organic aerosols to the marine atmosphere over the East China Sea: Insights from lipids, PAHs and phthalates.

    Science.gov (United States)

    Kang, Mingjie; Yang, Fan; Ren, Hong; Zhao, Wanyu; Zhao, Ye; Li, Linjie; Yan, Yu; Zhang, Yingjie; Lai, Senchao; Zhang, Yingyi; Yang, Yang; Wang, Zifa; Sun, Yele; Fu, Pingqing

    2017-12-31

    Total suspended particle (TSP) samples were collected during a marine cruise in the East China Sea from May 18 to June 12, 2014. They were analyzed for solvent extractable organic compounds (lipid compounds, PAHs and phthalates) using gas chromatography/mass spectrometry (GC/MS) to better understand the sources and source apportionment of aerosol pollution in the western North Pacific. Higher concentrations were observed in the terrestrially influenced aerosol samples on the basis of five-day backward air mass trajectories, especially for aerosols collected near coastal areas. Phthalates were found to be the dominant species among these measured compound classes (707±401ngm -3 for daytime and 313±155ngm -3 for nighttime), followed by fatty acids, fatty alcohols, n-alkanes and PAHs. In general, the daytime abundances for these compounds are higher than nighttime, possibly attributable to more intensive anthropogenic activities during the daytime. The factor analysis indicates that biomass burning, fungal activities and fossil fuel combustion maybe the main emission sources for organic aerosols over the East China Sea. This study demonstrates that the East Asian continent can be a natural emitter of biogenic and anthropogenic organics to the marine atmosphere through long-range transport, which controls the chemical composition and concentration of organic aerosols over the East China Sea. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Validation of MODIS derived aerosol optical depth and an investigation on aerosol transport over the South East Arabian Sea during ARMEX-II

    Directory of Open Access Journals (Sweden)

    M. Aloysius

    2009-06-01

    Full Text Available The influence of wind and humidity on aerosol optical depth (AOD over the Arabian sea is being investigated using MODIS (Moderate Resolution Imaging Spectroradiometer Level 3 (Collection-5 and NCEP (National Centres for Environmental Prediction reanalysis data for the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II over the South East Arabian Sea (SEAS in the pre-monsoon period (14 March–10 April 2003. In order to qualify MODIS data for this study, MODIS aerosol parameters were first compared with ship borne Microtops measurements. This showed correlations 0.96–0.97 in the case of spectral AODs and a correlation 0.72 for the angstrom exponents. The daily AOD data from MODIS and winds from NCEP reveal that the ship observed episodic enhancement and decay of AOD at the TSL (Time Series Location during 23 March–6 April 2003 was caused by the southward drift of an aerosol pocket driven by an intensification and reduction of surface pressure in the North Western Arabian Sea with a low altitude convergence prevailing over SEAS. The AOD increase coincided with a decrease in the Angstrom exponent and the fine mode fraction suggesting the pocket being dominated by coarse mode particles. A partial correlation analysis reveals that the lower altitude wind convergence is the most influential atmospheric variable in modulating AOD over the ARMEX-II domain during the TSL period. However, surface winds at a distant zone in the north/north west upwind direction also had a moderate influence, though with a lag of two days. But this effect was minor since the winds were not strong enough to produce marine aerosols matching with the high AODs over the ARMEX-II domain. These findings and the similarity between MODIS column mass concentration and the ship borne QCM (Quartz Crystal Microbalance measured coarse mode mass concentration, suggest that the aerosol pocket was mostly composed of coarse mode mineral dust in the lower atmospheric altitudes

  2. Separating refractory and non-refractory particulate chloride and estimating chloride depletion by aerosol mass spectrometry in a marine environment

    OpenAIRE

    I. Nuaaman; S.-M. Li; K. L. Hayden; T. B. Onasch; P. Massoli; D. Sueper; D. R. Worsnop; T. S. Bates; P. K. Quinn; R. McLaren

    2015-01-01

    Aerosol composition and concentration measurements along the coast of California were obtained using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) onboard the research vessel Atlantis during the CalNex study in 2010. This paper focuses on the measurement of aerosol chloride using the HR-AMS that can be ambiguous in regions with significant quantities of sea salt aerosols. This ambiguity arises due to large differences in the sensitivity of the HR...

  3. Elemental and organic carbon in aerosols over urbanized coastal region (southern Baltic Sea, Gdynia).

    Science.gov (United States)

    Lewandowska, Anita; Falkowska, Lucyna; Murawiec, Dominika; Pryputniewicz, Dorota; Burska, Dorota; Bełdowska, Magdalena

    2010-09-15

    Studies on PM 10, total particulate matter (TSP), elemental carbon (EC) and organic carbon (OC) concentrations were carried out in the Polish coastal zone of the Baltic Sea, in urbanized Gdynia. The interaction between the land, the air and the sea was clearly observed. The highest concentrations of PM 10, TSP and both carbon fractions were noted in the air masses moving from southern and western Poland and Europe. The EC was generally of primary origin and its contribution to TSP and PM 10 mass was on average 2.3% and 3.7% respectively. Under low wind speed conditions local sources (traffic and industry) influenced increases in elemental carbon and PM 10 concentrations in Gdynia. Elemental carbon demonstrated a pronounced weekly cycle, yielding minimum values at the weekend and maximum values on Thursdays. The role of harbors and ship yards in creating high EC concentrations was clearly observed. Concentration of organic carbon was ten times higher than that of elemental carbon, and the average OC contribution to PM 10 mass was very high (31.6%). An inverse situation was observed when air masses were transported from over the Atlantic Ocean, the North Sea and the Baltic Sea. These clean air masses were characterized by the lowest concentrations of all analysed compounds. Obtained results for organic and elemental carbon fluxes showed that atmospheric aerosols can be treated, along with water run-off, as a carbon source for the coastal waters of the Baltic Sea. The enrichment of surface water was more effective in the case of organic carbon (0.27+/-0.19 mmol m(-2) d(-1)). Elemental carbon fluxes were one order of magnitude smaller, on average 0.03+/-0.04 mmol m(-2) d(-1). We suggest that in some situations atmospheric carbon input can explain up to 18% of total carbon fluxes into the Baltic coastal waters. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Assessment of aerosol optics, microphysics, and transport process of biomass-burning haze over northern SE Asia: 7-SEAS AERONET observations

    Science.gov (United States)

    Wang, S.; Giles, D. M.; Eck, T. F.; Lin, N.; Tsay, S.; Holben, B. N.

    2013-12-01

    Initiated in 2007, the Seven South East Asian Studies (7-SEAS) is aimed to facilitate an interdisciplinary research on the aerosol environment in SE Asia (SEA) as a whole, promote international collaboration, and further enhance scientific understanding of the impact of biomass burning on clouds, atmospheric radiation, hydrological cycle, and region climates. One of the key measurements proposed in the 7-SEAS is the NASA/AERONET (AErosol RObotic NETwork) observation, which provides helpful information on columnar aerosol optical properties and allows us consistently to examine biomass-burning aerosols across northern SEA from ground-based remote-sensing point of view. In this presentation, we will focus on the two 7-SEAS field deployments, i.e. the 2012 Son La Experiment and the 2013 BASELInE (Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles and Interactions Experiment). We analyze the daytime variation of aerosol by using consistent measurements from 15 of AERONET sites over Indochina, the South China Sea, and Taiwan. Spatiotemporal characteristics of aerosol optical properties (e.g., aerosol optical depth (AOD), fine/coarse mode AOD, single-scattering albedo, asymmetry factor) will be discussed. Strong diurnal variation of aerosol optical properties was observed to be attributed to planetary boundary layer (PBL) dynamics. A comparison between aerosol loading (i.e. AOD) and surface PM2.5 concentration will be presented. Our results demonstrate that smoke aerosols emitted from agriculture burning that under certain meteorological conditions can degrade regional air quality 3000 km from the source region, with additional implications for aerosol radiative forcing and regional climate change over northern SE Asia.

  5. Aerosol formation of Sea-Urchin-like nanostructures of carbon nanotubes on bimetallic nanocomposite particles

    International Nuclear Information System (INIS)

    Kim, S. H.; Wang, C.; Zachariah, M. R.

    2011-01-01

    With the advantage of continuous production of pure carbon nanotubes (CNTs), a new simple aerosol process for the formation of CNTs was developed. A combination of conventional spray pyrolysis and thermal chemical vapor deposition enabled the formation unusual sea-urchin-like carbon nanostructures composed of multi-walled CNTs and metal composite nanoparticles. The CNTs formed were relatively untangled and uniform with a diameter of less than∼10 nm. The key to the formation of CNTs in this way was to create a substrate particle containing both a catalytic and non-catalytic component, which prevented coking. The density of the CNTs grown on the spherical metal nanoparticles could be controlled by perturbing the density of the metal catalysts (Fe) in the host non-catalytic metal particle matrix (Al). Mobility size measurement was identified as a useful technique to real-time characterization of either the catalytic formation of thin carbon layer or CNTs on the surface of the metal aerosol. These materials have shown unique properties in enhancing the thermal conductivity of fluids. Other potential advantages are that the as-produced material can be manipulated easily without the concern of high mobility of conventional nanowires, and then subsequently released at the desired time in an unagglomerated state.

  6. Recovery from episodic acidification delayed by drought and high sea salt deposition

    Directory of Open Access Journals (Sweden)

    H. Laudon

    2008-03-01

    Full Text Available For the prediction of episodic acidification large uncertainties are connected to climatic variability and its effect on drought conditions and sea-salt episodes. In this study data on 342 hydrological episodes in 25 Swedish streams, sampled over 10 years, have been analyzed using a recently developed episode model. The results demonstrate that drought is the most important factor modulating the magnitude of the anthropogenic influence on pH and ANC during episodes. These modulating effects are especially pronounced in southern and central Sweden, where the historically high acid deposition has resulted in significant S pools in catchment soils. The results also suggest that the effects of episodic acidification are becoming less severe in many streams, but this amelioration is less clear in coastal streams subject to high levels of sea-salt deposition. Concurrently with the amelioration of the effects of episodic acidification, regional climate models predict that temperatures will increase in Sweden during the coming decades, accompanied by reductions in summer precipitation and more frequent storms during fall and winter in large areas of the country. If these predictions are realized delays in streams' recovery from episodic acidification events can be expected.

  7. Changing Sediment Dynamics of a Mature Backbarrier Salt Marsh in Response to Sea-Level Rise and Storm Events

    Directory of Open Access Journals (Sweden)

    Mark Schuerch

    2018-05-01

    Full Text Available Our study analyses the long-term development of a tidal backbarrier salt marsh in the northern German Wadden Sea. The focus lies on the development of the high-lying, inner, mature part of the salt marsh, which shows a striking history of changing sediment dynamics. The analysis of high-resolution old aerial photographs and sampled sediment cores suggests that the mature part of the marsh was shielded by a sand barrier from the open sea for decades. The supply with fine-grained sediments occurred from the marsh inlet through the tidal channels to the inner salt marsh. Radiometric dating (210Pb and 137Cs reveals that the sedimentation pattern changed fundamentally around the early-mid 1980s when the sedimentation rates increased sharply. By analyzing the photographic evidence, we found that the sand barrier was breached during storm events in the early 1980s. As a result, coarse-grained sediments were brought directly through this overwash from the sea to the mature part of the salt marsh and increased the sedimentation rates. We show that the overwash and the channels created by these storm events built a direct connection to the sea and reduced the distance to the sediment source which promoted salt marsh growth and a supply with coarse-grained sediments. Consequently, the original sediment input from the tidal channels is found to play a minor role in the years following the breach event. The presented study showcases the morphological development of a mature marsh, which contradicts the commonly accepted paradigm of decreasing sedimentation rates with increasing age of the marsh. We argue that similar trends are likely to be observed in other backbarrier marshes, developing in the shelter of unstabilized sand barriers. It further highlights the question of how resilient these salt marshes are toward sea level rise and how extreme storm events interfere in determining the resilience of a mature salt marsh.

  8. Carbon burial and storage in tropical salt marshes under the influence of sea level rise.

    Science.gov (United States)

    Ruiz-Fernández, A C; Carnero-Bravo, V; Sanchez-Cabeza, J A; Pérez-Bernal, L H; Amaya-Monterrosa, O A; Bojórquez-Sánchez, S; López-Mendoza, P G; Cardoso-Mohedano, J G; Dunbar, R B; Mucciarone, D A; Marmolejo-Rodríguez, A J

    2018-07-15

    Coastal vegetated habitats can be important sinks of organic carbon (C org ) and mitigate global warming by sequestering significant quantities of atmospheric CO 2 and storing sedimentary C org for long periods, although their C org burial and storage capacity may be affected by on-going sea level rise and human intervention. Geochemical data from published 210 Pb-dated sediment cores, collected from low-energy microtidal coastal wetlands in El Salvador (Jiquilisco Bay) and in Mexico (Salada Lagoon; Estero de Urias Lagoon; Sian Ka'an Biosphere Reserve) were revisited to assess temporal changes (within the last 100years) of C org concentrations, storage and burial rates in tropical salt marshes under the influence of sea level rise and contrasting anthropization degree. Grain size distribution was used to identify hydrodynamic changes, and δ 13 C to distinguish terrigenous sediments from those accumulated under the influence of marine transgression. Although the accretion rate ranges in all sediment records were comparable, C org concentrations (0.2-30%), stocks (30-465Mgha -1 , by extrapolation to 1m depth), and burial rates (3-378gm -2 year -1 ) varied widely within and among the study areas. However, in most sites sea level rise decreased C org concentrations and stocks in sediments, but increased C org burial rates. Lower C org concentrations were attributed to the input of reworked marine particles, which contribute with a lower amount of C org than terrigenous sediments; whereas higher C org burial rates were driven by higher mass accumulation rates, influenced by increased flooding and human interventions in the surroundings. C org accumulation and long-term preservation in tropical salt marshes can be as high as in mangrove or temperate salt marsh areas and, besides the reduction of C org stocks by ongoing sea level rise, the disturbance of the long-term buried C org inventories might cause high CO 2 releases, for which they must be protected as a part of

  9. Performance investigation of a salt gradient solar pond coupled with desalination facility near the Dead Sea

    International Nuclear Information System (INIS)

    Saleh, A.; Qudeiri, J.A.; Al-Nimr, M.A.

    2011-01-01

    Solar ponds provide the most convenient and least expensive option for heat storage for daily and seasonal cycles. This is particularly important for a desalination facility, if steady and constant water production is required. If, in addition to high storage capacity, other favorable conditions exist, the salt gradient solar ponds (SGSPs) are expected to be able to carry the entire load of a large-scale flash desalination plants without dependence upon supplementary sources. This paper presents a performance investigation of a SGSP coupled with desalination plant under Jordanian climatic conditions. This is particularly convenient in the Dead Sea region characterized by high solar radiation intensities, high ambient temperature most of the year, and by the availability of high concentration brine. It was found that a 3000 m 2 solar pond installed near the Dead Sea is able to provide an annual average production rate of 4.3 L min -1 distilled water compared with 3.3 L min -1 that would be produced by El Paso solar pond, which has the same surface area. Based on this study, solar ponds appear to be a feasible and an appropriate technology for water desalination near the Dead Sea in Jordan. -- Research highlights: → A performance investigation of a solar pond coupled with desalination plant. → Dead Sea area is characterized by availability of high solar radiation and brine. → The Dead Sea solar pond can provide production rate of 4.3 L min -1 . → El Paso solar pond has production rate of 3.32 L min -1 . The improvement is about 30%. → The solar pond with desalination investigated showed to be a feasible technology.

  10. Single-particle investigation of summertime and wintertime Antarctic sea spray aerosols using low-Z particle EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques

    Directory of Open Access Journals (Sweden)

    H.-J. Eom

    2016-11-01

    Full Text Available Two aerosol samples collected at King Sejong Korean scientific research station, Antarctica, on 9 December 2011 in the austral summer (sample S1 and 23 July 2012 in the austral winter (sample S2, when the oceanic chlorophyll a levels on the collection days of the samples were quite different, by  ∼  19 times (2.46 vs. 0.13 µg L−1, respectively, were investigated on a single-particle basis using quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA, called low-Z particle EPMA, Raman microspectrometry (RMS, and attenuated total reflection Fourier transform infrared (ATR-FTIR imaging techniques to obtain their characteristics based on the elemental chemical compositions, molecular species, and mixing state. X-ray analysis showed that the supermicron summertime and wintertime Antarctic aerosol samples have different elemental chemical compositions, even though all the individual particles analyzed were sea spray aerosols (SSAs; i.e., the contents of C, O, Ca, S, and Si were more elevated, whereas Cl was more depleted, for sample S1 than for sample S2. Based on qualitative analysis of the chemical species present in individual SSAs by the combined application of RMS and ATR-FTIR imaging, different organic species were observed in samples S1 and S2; i.e., Mg hydrate salts of alanine were predominant in samples S1 and S2, whereas Mg salts of fatty acids internally mixed with Mg hydrate salts of alanine were significant in sample S2. Although CaSO4 was observed significantly in both samples S1 and S2, other inorganic species, such as Na2SO4, NaNO3, Mg(NO32, SiO2, and CH3SO3Mg, were observed more significantly in sample S1, suggesting that those compounds may be related to the higher phytoplankton activity in summer.

  11. CLOUDS, AEROSOLS, RADIATION AND THE AIR-SEA INTERFACE OF THE SOUTHERN OCEAN: ESTABLISHING DIRECTIONS FOR FUTURE RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Robert [University of Washington; Bretherton, Chris [University of Washington; McFarquhar, Greg [University of Illinois - Urbana; Protat, Alain [Bureau of Meteorology - Melbourne; Quinn, Patricia [NOAA PMEL; Siems, Steven [Monash Univ., Melbourne, VIC (Australia); Jakob, Christian [Monash Univ., Melbourne, VIC (Australia); Alexander, Simon [Australian Antarctic Division; Weller, Bob [Woods Hole Oceanographic Institute

    2014-09-29

    A workshop sponsored by the Department of Energy was convened at the University of Washington to discuss the state of knowledge of clouds, aerosols and air-sea interaction over the Southern Ocean and to identify strategies for reducing uncertainties in their representation in global and regional models. The Southern Ocean plays a critical role in the global climate system and is a unique pristine environment, yet other than from satellite, there have been sparse observations of clouds, aerosols, radiation and the air-sea interface in this region. Consequently, much is unknown about atmospheric and oceanographic processes and their linkage in this region. Approximately 60 scientists, including graduate students, postdoctoral fellows and senior researchers working in atmospheric and oceanic sciences at U.S. and foreign universities and government laboratories, attended the Southern Ocean Workshop. It began with a day of scientific talks, partly in plenary and partly in two parallel sessions, discussing the current state of the science for clouds, aerosols and air-sea interaction in the Southern Ocean. After the talks, attendees broke into two working groups; one focused on clouds and meteorology, and one focused on aerosols and their interactions with clouds. This was followed by more plenary discussion to synthesize the two working group discussions and to consider possible plans for organized activities to study clouds, aerosols and the air-sea interface in the Southern Ocean. The agenda and talk slides, including short summaries of the highlights of the parallel session talks developed by the session chars, are available at http://www.atmos.washington.edu/socrates/presentations/SouthernOceanPresentations/.

  12. Characteristics and Source Apportionment of Marine Aerosols over East China Sea Using a Source-oriented Chemical Transport Model

    Science.gov (United States)

    Kang, M.; Zhang, H.; Fu, P.

    2017-12-01

    Marine aerosols exert a strong influence on global climate change and biogeochemical cycling, as oceans cover beyond 70% of the Earth's surface. However, investigations on marine aerosols are relatively limited at present due to the difficulty and inconvenience in sampling marine aerosols as well as their diverse sources. East China Sea (ECS), lying over the broad shelf of the western North Pacific, is adjacent to the Asian mainland, where continental-scale air pollution could impose a heavy load on the marine atmosphere through long-range atmospheric transport. Thus, contributions of major sources to marine aerosols need to be identified for policy makers to develop cost effective control strategies. In this work, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model, which can directly track the contributions from multiple emission sources to marine aerosols, is used to investigate the contributions from power, industry, transportation, residential, biogenic and biomass burning to marine aerosols over the ECS in May and June 2014. The model simulations indicate significant spatial and temporal variations of concentrations as well as the source contributions. This study demonstrates that the Asian continent can greatly affect the marine atmosphere through long-range transport.

  13. On the contribution of organics to the North East Atlantic aerosol number concentration

    International Nuclear Information System (INIS)

    Bialek, Jakub; Dall’Osto, Manuel; Monahan, Ciaran; O’Dowd, Colin; Beddows, David

    2012-01-01

    k-means statistical-cluster analysis of submicron aerosol size distributions is combined with coincident humidity tandem differential mobility analyser data, leading to five unique aerosol categories for hygroscopic growth factors (HGFs): low sea-salt background marine, high sea-salt background marine, coastal nucleation, open ocean nucleation and anthropogenically influenced scenarios. When considering only marine conditions, and generic aerosol species associated with this environment (e.g. non-sea-salt sulfate, sea-salt, partly soluble organic matter and water insoluble organic matter), the two-year annual average contribution to aerosol number concentration from the different generic species was made up as follows: 46% (30–54%) of partially modified ammonium sulfate particles; 23% (11–40%) of partially modified sea-salt; and the remaining 31% (25–35%) contribution attributed to two distinct organic species as evidenced by different, but low, HGFs. The analysis reveals that on annual timescales, ∼30% of the submicron marine aerosol number concentration is sourced from predominantly organic aerosol while 60% of the anthropogenic aerosol number is predominantly organic. Coastal nucleation events show the highest contribution of the lowest HGF mode (1.19), although this contribution is more likely to be influenced by inorganic iodine oxides. While organic mass internally mixed with inorganic salts will lower the activation potential of these mixed aerosol types, thereby potentially reducing the concentration of cloud condensation nuclei (CCN), pure organic water soluble particles are still likely to be activated into cloud droplets, thereby increasing the concentration of CCN. A combination of dynamics and aerosol concentrations will determine which effect will prevail under given conditions. (letter)

  14. An 11-year analysis of satellite retrievals of dust aerosol over the Red Sea and the Persian Gulf

    Science.gov (United States)

    Banks, Jamie; Brindley, Helen; Schepanski, Kerstin; Stenchikov, Georgiy

    2017-04-01

    As enclosed seas bordering two large desert regions, the Saharan and Arabian deserts, the maritime environments of the Red Sea and the Persian Gulf are heavily influenced by the presence of desert dust aerosol. The inter-annual variability of dust presence over the Red Sea is analysed and presented, with respect to the summer-time latitudinal gradient in dust loading, which is at a maximum in the far south of the Red Sea and at a minimum in the far north. Two satellite aerosol optical depth (AOD) products from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) and the MODerate resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify this loading over the region. Over an eleven-year period from 2005-2015 the July mean SEVIRI AODs at 630 nm vary between 0.48 and 1.45 in the southern half of the Sea, while in the north this varies between 0.22 and 0.66. Inter-retrieval offsets are observed to occur at higher dust loadings, with pronounced positive MODIS-SEVIRI AOD offsets at AODs greater than 1, indicating substantial and systematic differences between the retrievals over the Red Sea at high dust loadings. These differences appear to be influenced in part by the differences in scattering angle range of the satellite measurements, implying that assumptions of particle shape introduce more substantial biases at the highest dust loadings.

  15. MATRIX (Multiconfiguration Aerosol TRacker of mIXing state: an aerosol microphysical module for global atmospheric models

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2008-10-01

    Full Text Available A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS climate model (ModelE are described. This module, which is based on the quadrature method of moments (QMOM, represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations.

    A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment

  16. Basement inheritance and salt tectonics in the SE Barents Sea: Insights from new potential field data

    Science.gov (United States)

    Gernigon, L.; Broenner, M.; Dumais, M. A.; Gradmann, S.; Grønlie, A.; Nasuti, A.; Roberts, D.

    2017-12-01

    The tectonic evolution of the former `grey zone' between Russia and Norway has so far remained poorly constrained due to a lack of geophysical data. In 2014, we carried out a new aeromagnetic survey (BASAR-14) in the southern part of the new Norwegian offshore territory. Caledonian and Timanian structures, highlighted by the new potential field data, dominate the basement patterns and have exerted a strong influence on the structure and development of the overlying basins and basement highs. Clearly associated with NW-SE-oriented Timanian trends, the Tiddlybanken Basin represents an atypical sag basin that developed at the southern edge of the Fedynsky High. Regional extension and rapid sedimentation initiated the salt tectonics in the Barents Sea in the Early Triassic. Some of the pillows became diapiric during the Early Triassic and rejuvenated during subsequent Jurassic-Tertiary episodes of regional extension and/or compression. At present, quite a few large diapiric salt domes along the Nordkapp and Tiddlybanken basins are relatively shallow, locally reaching the seabed and thus show a clear bathymetric and magnetic signature. Quantitative modelling along 2D seismic transects was also carried out to constrain the structural and basement composition of the study area. The predominant NE-SW Mesozoic trend of the Nordkapp Basin represents a major crustal hinge zone between the Finnmark Platform, poorly affected by major crustal deformation, and the Bjarmeland Platform where Late Palaeozoic rifting controlled the widespread accumulation of salt deposits in Late Carboniferous-Early Permian time. The entire structure and segmentation of the Nordkapp Basin have been influenced by the inherited basement configuration highlighted by the new aeromagnetic data. Both the Nordkapp and the Tiddlybanken basins appear to lie at the edge of a peculiar thick and rigid crustal feature that coincides with a highly magnetic region. The abrupt termination of the eastern Nordkapp

  17. Dynamics of phytoplankton community structure in the South China Sea in response to the East Asian aerosol input

    Science.gov (United States)

    Guo, C.; Yu, J.; Ho, T.-Y.; Wang, L.; Song, S.; Kong, L.; Liu, H.

    2012-04-01

    Recent studies have demonstrated atmospheric deposition as an important source of bioreactive compounds to the ocean. The South China Sea (SCS), where aerosol loading is among the highest in the world, however, is poorly studied, particularly on the in situ response of phytoplankton community structures to atmospheric deposition. By conducting a series of microcosm bioassays at different hydrographical locations and simulating different aerosol event scales, we observed both positive and negative responses to the input of East Asian (EA) aerosol with high nitrogen (N) and trace metal contents, in terms of biomass, composition and physiological characteristics of phytoplankton communities. High levels of aerosol loading relieved phytoplankton nitrogen and trace metal limitations in SCS, and thus increased total phytoplankton biomass, enhanced their physiological indicators (e.g. photosynthetic efficiency) and shifted phytoplankton assemblages from being dominated by picoplankton to microphytoplanton, especially diatoms. However, under low levels of aerosol loading, the composition shift and biomass accumulation were not apparent, suggesting that the stimulation effects might be counterbalanced by enhanced grazing mortality indicated by increased abundance of protist grazers. Trace metal toxicity of the aerosols might also be the reason for the reduction of picocyanobacteria when amended with high EA aerosols. The magnitude and duration of the deposition event, as well as the hydrographical and trophic conditions of receiving waters are also important factors when predicting the influence of an aerosol deposition event. Our results demonstrated different responses of phytoplankton and microbial food web dynamics to different scales of atmospheric input events in SCS and highlighted the need for achieving an accurate comprehension of atmospheric nutrient on the biogeochemical cycles of the oceans.

  18. Atmospheric correction of SeaWiFS ocean color imagery in the presence of absorbing aerosols off the Indian coast using a neuro-variational method

    Science.gov (United States)

    Brajard, J.; Moulin, C.; Thiria, S.

    2008-10-01

    This paper presents a comparison of the atmospheric correction accuracy between the standard sea-viewing wide field-of-view sensor (SeaWiFS) algorithm and the NeuroVaria algorithm for the ocean off the Indian coast in March 1999. NeuroVaria is a general method developed to retrieve aerosol optical properties and water-leaving reflectances for all types of aerosols, including absorbing ones. It has been applied to SeaWiFS images of March 1999, during an episode of transport of absorbing aerosols coming from pollutant sources in India. Water-leaving reflectances and aerosol optical thickness estimated by the two methods were extracted along a transect across the aerosol plume for three days. The comparison showed that NeuroVaria allows the retrieval of oceanic properties in the presence of absorbing aerosols with a better spatial and temporal stability than the standard SeaWiFS algorithm. NeuroVaria was then applied to the available SeaWiFS images over a two-week period. NeuroVaria algorithm retrieves ocean products for a larger number of pixels than the standard one and eliminates most of the discontinuities and artifacts associated with the standard algorithm in presence of absorbing aerosols.

  19. Influence of marine aerosols and aerotechnogenic load on chemical composition of rainwaters on small islands (ludas) of the White Sea

    Science.gov (United States)

    Gorbacheva, Tamara; Mazukhina, Svetlana; Isaeva, Ludmila; Shumilov, Oleg

    2013-04-01

    In June 2001 intensive monitoring plots were established on the island part of Kandalaksha Bay of the White Sea (the island Tonnaya Luda; 67o06'60"N; 32o24'12"E) with the installation of stationary rainwater collectors. The purpose was studying the chemical composition of rain waters in the zone of cumulative influence of marine aerosols and aerotechnogenic load. Water sampling was carried out monthly during the vegetative season of 2001 and 2002. pH of rain water was determined by potentiometric method without preliminary filtration. The samples were passed through the paper filter with the pore diameter of 1-2.5 microns, the analysis of filtrate carried out by methods of atomic emission spectrometry (K, Na) and atomic absorption spectrometry (Ca, Mg, Zn, Mn, Cu, Ni, Al, Fe), total P and P of phosphates, Si and NH4+ - by photocolorimetry, total carbon - by bichromate method, NO3-, SO42-, Cl--by ion exchange chromatography method. Balance method was chosen as a research basis to determine the interrelation of rain water organic matter and dynamics of its redistribution under the influence of natural and technogenic factors. The difference between the cations sum (including NH4+and H+) and mineral acids anions sum (SO42-, Cl-, NO3-) was identified as organic acids anions concentration (μeq l-1). The level of Na, Cl-, K, Ca, Mg, SO42-, Sr in rainwaters on the island and the remote areas is indicative of the possible influence of marine aerosols on the island part of the White Sea. The increase of Al, Cu, Ni, Cd, Co concentrations in rainwaters up to one order against the background values points to the cumulative influence of the emissions of industrial enterprises located in the region. The relative stability of pH values of rain waters during all seasons indicates to the buffer action of weak organic acids anions. The correlation analysis of ionic structure in normal concentrations has allowed us to estimate the distribution of the cationic part from the

  20. Sea spray aerosol chemical composition: elemental and molecular mimics for laboratory studies of heterogeneous and multiphase reactions.

    Science.gov (United States)

    Bertram, Timothy H; Cochran, Richard E; Grassian, Vicki H; Stone, Elizabeth A

    2018-04-03

    Sea spray aerosol particles (SSA), formed through wave breaking at the ocean surface, contribute to natural aerosol particle concentrations in remote regions of Earth's atmosphere, and alter the direct and indirect effects of aerosol particles on Earth's radiation budget. In addition, sea spray aerosol serves as suspended surface area that can catalyze trace gas reactions. It has been shown repeatedly that sea spray aerosol is heavily enriched in organic material compared to the surface ocean. The selective enrichment of organic material complicates the selection of representative molecular mimics of SSA for laboratory or computational studies. In this review, we first provide a short introduction to SSA formation processes and discuss chemical transformations of SSA that occur in polluted coastal regions and remote pristine air. We then focus on existing literature of the chemical composition of nascent SSA generated in controlled laboratory experiments and field investigations. We combine the evidence on the chemical properties of nascent SSA with literature measurements of SSA water uptake to assess SSA molecular composition and liquid water content. Efforts to speciate SSA organic material into molecular classes and specific molecules have led to the identification of saccharides, alkanes, free fatty acids, anionic surfactants, dicarboxylic acids, amino acids, proteinaceous matter, and other large macromolecules. However to date, less than 25% of the organic mass of nascent SSA has been quantified at a molecular level. As discussed here, quantitative measurements of size resolved elemental ratios, combined with determinations of water uptake properties, provides unique insight on the concentration of ions within SSA as a function of particle size, pointing to a controlling role for relative humidity and the hygroscopicity of SSA organic material at small particle diameters.

  1. The Influence of Air-Sea Fluxes on Atmospheric Aerosols During the Summer Monsoon Over the Tropical Indian Ocean

    Science.gov (United States)

    Zavarsky, Alex; Booge, Dennis; Fiehn, Alina; Krüger, Kirstin; Atlas, Elliot; Marandino, Christa

    2018-01-01

    During the summer monsoon, the western tropical Indian Ocean is predicted to be a hot spot for dimethylsulfide emissions, the major marine sulfur source to the atmosphere, and an important aerosol precursor. Other aerosol relevant fluxes, such as isoprene and sea spray, should also be enhanced, due to the steady strong winds during the monsoon. Marine air masses dominate the area during the summer monsoon, excluding the influence of continentally derived pollutants. During the SO234-2/235 cruise in the western tropical Indian Ocean from July to August 2014, directly measured eddy covariance DMS fluxes confirm that the area is a large source of sulfur to the atmosphere (cruise average 9.1 μmol m-2 d-1). The directly measured fluxes, as well as computed isoprene and sea spray fluxes, were combined with FLEXPART backward and forward trajectories to track the emissions in space and time. The fluxes show a significant positive correlation with aerosol data from the Terra and Suomi-NPP satellites, indicating a local influence of marine emissions on atmospheric aerosol numbers.

  2. The flushing and exchange of the South China Sea derived from salt and mass conservation

    Science.gov (United States)

    Liu, Yang; Bye, John A. T.; You, Yuzhu; Bao, Xianwen; Wu, Dexing

    2010-07-01

    In this paper, we use two kinds of hydrographic data, historical cruise data, Array for Real-time Geostrophic Oceanography (Argo) float data, and atmospheric data to study the water exchange between the South China Sea (SCS) and the Pacific Ocean through the Luzon Strait. The annual mean distributions of temperature and salinity at five different levels in the SCS and the adjacent Pacific Ocean are presented, which indicate the occurrence of active water exchange through the Luzon Strait. The flushing and exchange of the SCS are then determined by the application of salt and mass conservation in a multi-layered thermohaline system, using an estimate of the net rainfall obtained from reanalysis data. The results show that the annual mean flushing time is 44±8 months with an inflow rate of 11±2 Sv (1 Sv=10 6 m 3 s -1), part of which recirculates at a deeper level through the Luzon Strait, the remainder (6±2 Sv) forming the SCS throughflow. The diffusive influx of salt is also estimated and accounts for about 10% of the total influx, and hence advection dominates over diffusion in the water exchange through the Luzon Strait. The seasonal cycle of exchange shows a maximum in autumn and winter of about twice the annual mean rate.

  3. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

    OpenAIRE

    Gantt, B.; Kelly, J. T.; Bash, J. O.

    2015-01-01

    Sea spray aerosols (SSAs) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. Model evaluations of SSA emissions have mainly focused on the global scale, but regional-scale evaluations are also important due to the localized impact of SSAs on atmospheric chemistry near the coast. In this study, SSA emissions in the Community Multiscale Air Quality (CMAQ) model were updated to enhance the...

  4. Role of dynamics in the advection of aerosols over the Arabian Sea ...

    Indian Academy of Sciences (India)

    Aerosol cluster; circulation dynamics; wind convergence; regional climate model. J. Earth Syst. Sci. .... anthropogenic aerosols because of lack of informa- tion on the ..... and ground-based measurements; Global Planet. Change. 72 164–181.

  5. Using MSG to monitor the evolution of severe convective storms over East Mediterranean Sea and Israel, and its response to aerosol loading

    Directory of Open Access Journals (Sweden)

    I. M. Lensky

    2007-08-01

    Full Text Available Convective storms over East Mediterranean sea and Israel were tracked by METEOSAT Second Generation (MSG. The MSG data was used to retrieve time series of the precipitation formation processes in the clouds, the temperature of onset of precipitation, and an indication to aerosol loading over the sea. Strong correlation was found between the aerosol loading and the depth above cloud base required for the initialization of effective precipitation processes (indicated by the effective radius = 15 µm threshold. It seems from the data presented here that the clouds' response to the aerosol loading is very short.

  6. Chemical characteristics of aerosols in MABL of Bay of Bengal and ...

    Indian Academy of Sciences (India)

    the water-soluble ion composition of bulk-aerosols over BoB, in contrast to Arabian Sea, arises from advective transport of continental pollutants to the. Bay region. This is further reflected in the higher abundance of OC and EC over BoB. The near quantitative Cl. −. -depletion from sea-salts by chemi- cal interaction with ...

  7. Evaluation of thermal and dynamic impacts of summer dust aerosols on the Red Sea

    KAUST Repository

    Cahill, Bronwyn

    2017-01-16

    The seasonal response of upper ocean processes in the Red Sea to summer-time dust aerosol perturbations is investigated using an uncoupled regional ocean model. We find that the upper limit response is highly sensitive to dust-induced reductions in radiative fluxes. Sea surface cooling of −1°C and −2°C is predicted in the northern and southern regions, respectively. This cooling is associated with a net radiation reduction of −40 W m−2 and −90 W m−2 over the northern and southern regions, respectively. Larger cooling occurs below the mixed layer at 75 m in autumn, −1.2°C (north) and −1.9°C (south). SSTs adjust more rapidly (ca. 30 days) than the subsurface temperatures (seasonal time scales), due to stronger stratification and increased mixed layer stability inhibiting the extent of vertical mixing. The basin average annual heat flux reverses sign and becomes positive, +4.2 W m−2 (as compared to observed estimates −17.3 W m−2) indicating a small gain of heat from the atmosphere. When we consider missing feedbacks from atmospheric processes in our uncoupled experiment, we postulate that the magnitude of cooling and the time scales for adjustment will be much less, and that the annual heat flux will not reverse sign but nevertheless be reduced as a result of dust perturbations. While our study highlights the importance of considering coupled ocean-atmosphere processes on the net surface energy flux in dust perturbation studies, the results of our uncoupled dust experiment still provide an upper limit estimate of the response of the upper ocean to dust-induced radiative forcing perturbations.

  8. Evaluation of thermal and dynamic impacts of summer dust aerosols on the Red Sea

    KAUST Repository

    Cahill, Bronwyn; Toumi, Ralf; Stenchikov, Georgiy L.; Osipov, Sergey; Brindley, Helen

    2017-01-01

    The seasonal response of upper ocean processes in the Red Sea to summer-time dust aerosol perturbations is investigated using an uncoupled regional ocean model. We find that the upper limit response is highly sensitive to dust-induced reductions in radiative fluxes. Sea surface cooling of −1°C and −2°C is predicted in the northern and southern regions, respectively. This cooling is associated with a net radiation reduction of −40 W m−2 and −90 W m−2 over the northern and southern regions, respectively. Larger cooling occurs below the mixed layer at 75 m in autumn, −1.2°C (north) and −1.9°C (south). SSTs adjust more rapidly (ca. 30 days) than the subsurface temperatures (seasonal time scales), due to stronger stratification and increased mixed layer stability inhibiting the extent of vertical mixing. The basin average annual heat flux reverses sign and becomes positive, +4.2 W m−2 (as compared to observed estimates −17.3 W m−2) indicating a small gain of heat from the atmosphere. When we consider missing feedbacks from atmospheric processes in our uncoupled experiment, we postulate that the magnitude of cooling and the time scales for adjustment will be much less, and that the annual heat flux will not reverse sign but nevertheless be reduced as a result of dust perturbations. While our study highlights the importance of considering coupled ocean-atmosphere processes on the net surface energy flux in dust perturbation studies, the results of our uncoupled dust experiment still provide an upper limit estimate of the response of the upper ocean to dust-induced radiative forcing perturbations.

  9. Grazing management can counteract the impacts of climate change-induced sea level rise on salt marsh-dependent waterbirds

    DEFF Research Database (Denmark)

    Clausen, Kevin Kuhlmann; Stjernholm, Michael; Clausen, Preben

    2013-01-01

    with these changes. In addition, we quantify the areal extent of inadequate salt marsh management in four EU Special Protection Areas for Birds, and demonstrate concurrent population dynamics in four species relying on managed habitats. We conclude by investigating potential compensation for climate change......1) Climate change–induced rises in sea level threaten to drastically reduce the areal extent of important salt marsh habitats for large numbers of waterfowl and waders. Furthermore, recent changes in management practice have rendered existent salt marshes unfavourable to many birds, as lack...... (around 1 cow per hectare) is an important initiative to counteract the accelerating climate change–induced habitat loss in near-coastal areas across the globe, and to secure priority salt marsh habitats that support internationally important populations of breeding, wintering and staging waterfowl...

  10. Fractal-like thickness and topography of the salt layer in a pillows province of the southern North Sea

    Science.gov (United States)

    Hernandez Maya, K.; Mitchell, N. C.; Huuse, M.

    2017-12-01

    Salt topography and thickness variations are important for testing theories of how halokinetic deformation proceeds. The ability to predict thickness variations of salt at small scale is also important for reservoir evaluations, as breach of the salt layer can lead to loss of petroleum fluids and can be difficult to evaluate from seismic reflection data. Relevant to these issues, we here report analysis of data on salt layer topography and thickness from the southern North Sea, where the salt is organized into pillows. These data were derived by the Geological Survey of the Netherlands (TNO) from industry 3D seismic reflection data combined with a dense network of well information. Highs and lows in the topography of the upper salt interface occur spaced over a variety of lengthscales. Power spectral analysis of the interface topography reveals a simple inverse power law relationship between power spectral density and spatial wave number. The relationship suggests that the interface is a self-affine fractal with a fractal dimension of 2.85. A similar analysis of the salt layer thickness also suggests a fractal-like power law. Whereas the layer thickness power law is unsurprising as the underlying basement topography dominates the thickness and it also has a fractal-like power spectrum, the salt topography is not so easily explained as not all the basement faults are overlaid by salt pillows, instead some areas of the dataset salt thinning overlies faults. We consider instead whether a spatially varied loading of the salt layer may have caused this fractal-like geometry. Varied density and thickness of overburdening layers seem unlikely causes, as thicknesses of layers and their reflectivities do not vary sympathetically with the topography of the interface. The composition of the salt layer varies with the relative proportions of halite and denser anhydrite and other minerals. Although limited in scope and representing the mobilized salt layer, the information from

  11. Regional Responses to Black Carbon Aerosols: The Importance of Air-Sea Interaction

    Science.gov (United States)

    Gnanadesikan, A.; Scott, A. A.; Pradal, M.-A.; Seviour, W. J. M.; Waugh, D. W.

    2017-12-01

    The impact of modern black carbon aerosols on climate via their changes in radiative balance is studied using a coupled model where sea surface temperatures (SSTs) are allowed to vary and an atmosphere-only version of the same model where SSTs are held fixed. Allowing the ocean to respond is shown to have a profound impact on the pattern of temperature change. Particularly, large impacts are found in the North Pacific (which cools by up to 1 K in the coupled model) and in north central Asia (which warms in the coupled simulation and cools in the fixed SST simulation). Neither set of experiments shows large changes in surface temperatures in the Southeast Asian region where the atmospheric burden of black carbon is highest. These results are related to the stabilization of the atmosphere and changes in oceanic heat transport. Over the North Pacific, atmospheric stabilization results in an increase in stratiform clouds. The resulting shading reduces evaporation, freshening the surface layer of the ocean and reducing the inflow of warm subtropical waters. Over the land, a delicate balance between greater atmospheric absorption, shading of the surface and changes in latent cooling of the surface helps to determine whether warming or cooling is seen. Our results emphasize the importance of coupling in determining the response of the climate system to black carbon and suggest that black carbon may play an important role in modulating climate change over the North Pacific.

  12. Molecular Diversity of Sea Spray Aerosol Particles: Impact of Ocean Biology on Particle Composition and Hygroscopicity

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, Richard E.; Laskina, Olga; Trueblood, Jonathan; Estillore, Armando D.; Morris, Holly S.; Jayarathne, Thilina; Sultana, Camile M.; Lee, Christopher; Lin, Peng; Laskin, Julia; Laskin, Alexander; Dowling, Jackie; Qin, Zhen; Cappa, Christopher; Bertram, Timothy; Tivanski, Alexei V.; Stone, Elizabeth; Prather, Kimberly; Grassian, Vicki H.

    2017-05-01

    The impact of sea spray aerosol (SSA) on climate depends on the size and chemical composition of individual particles that make-up the total SSA ensemble. While the organic fraction of SSA has been characterized from a bulk perspective, there remains a lack of understanding as to the composition of individual particles within the SSA ensemble. To better understand the molecular components within SSA particles and how SSA composition changes with ocean biology, simultaneous measurements of seawater and SSA were made during a month-long mesocosm experiment performed in an ocean-atmosphere facility. Herein, we deconvolute the composition of freshly emitted SSA devoid of anthropogenic and terrestrial influences by characterizing classes of organic compounds as well as specific molecules within individual SSA particles. Analysis of SSA particles show that the diversity of molecules within the organic fraction varies between two size fractions (submicron and supermicron) with contributions from fatty acids, monosaccharides, polysaccharides and siliceous material. Significant changes in the distribution of these compounds within individual particles are observed to coincide with the rise and fall of phytoplankton and bacterial populations within the seawater. Furthermore, water uptake is impacted as shown by hygroscopicity measurements of model systems composed of representative organic compounds. Thus, the how changes in the hygroscopic growth of SSA evolves with composition can be elucidated. Overall, this study provides an important connection between biological processes that control the composition of seawater and changes in single particle composition which will enhances our ability to predict the impact of SSA on climate.

  13. Mobilization of arsenic, lead, and mercury under conditions of sea water intrusion and road deicing salt application

    Science.gov (United States)

    Sun, Hongbing; Alexander, John; Gove, Brita; Koch, Manfred

    2015-09-01

    Water geochemistry data from complexly designed salt-solution injection experiments in the laboratory, coastal aquifers of Bangladesh and Italy, taken from the literature, and two salted watersheds of New Jersey, US were collected and analyzed to study the geochemical mechanisms that mobilize As, Pb, and Hg under varied salting conditions. Overall, increased NaCl-concentrations in aquifers and soil are found to increase the release of Pb and Hg into the water. Reducing environments and possible soil dispersion by hydrated Na+ are found to lead to an increase of As-concentration in water. However, the application of a pure NaCl salt solution in the column injection experiment was found to release less As, Pb, and Hg initially from the soil and delay their concentration increase, when compared to the application of CaCl2 and NaCl mixed salts (at 6:4 weight ratio). The concentration correlation dendrogram statistical analyses of the experimental and field data suggest that the release of As, Hg, and Pb into groundwater and the soil solution depends not only on the salt level and content, but also on the redox condition, dissolved organic matter contents, competitiveness of other ions for exchange sites, and source minerals. With the ongoing over-exploration of coastal aquifers from increased pumping, continued sea-level rise, and increased winter deicing salt applications in salted watersheds of many inland regions, the results of this study will help understand the complex relation between the concentrations of As, Pb, and Hg and increased salt level in a coastal aquifer and in soils of a salted watershed.

  14. Effect of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida.

    Science.gov (United States)

    Langevin, Christian D; Zygnerski, Michael

    2013-01-01

    A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  15. Effects of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida

    Science.gov (United States)

    Langevin, Christian D.; Zygnerski, Michael

    2013-01-01

    A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise.

  16. Primary aerosol and secondary inorganic aerosol budget over the Mediterranean Basin during 2012 and 2013

    Science.gov (United States)

    Guth, Jonathan; Marécal, Virginie; Josse, Béatrice; Arteta, Joaquim; Hamer, Paul

    2018-04-01

    In the frame of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx), we analyse the budget of primary aerosols and secondary inorganic aerosols over the Mediterranean Basin during the years 2012 and 2013. To do this, we use two year-long numerical simulations with the chemistry-transport model MOCAGE validated against satellite- and ground-based measurements. The budget is presented on an annual and a monthly basis on a domain covering 29 to 47° N latitude and 10° W to 38° E longitude. The years 2012 and 2013 show similar seasonal variations. The desert dust is the main contributor to the annual aerosol burden in the Mediterranean region with a peak in spring, and sea salt being the second most important contributor. The secondary inorganic aerosols, taken as a whole, contribute a similar level to sea salt. The results show that all of the considered aerosol types, except for sea salt aerosols, experience net export out of our Mediterranean Basin model domain, and thus this area should be considered as a source region for aerosols globally. Our study showed that 11 % of the desert dust, 22.8 to 39.5 % of the carbonaceous aerosols, 35 % of the sulfate and 9 % of the ammonium emitted or produced into the study domain are exported. The main sources of variability for aerosols between 2012 and 2013 are weather-related variations, acting on emissions processes, and the episodic import of aerosols from North American fires. In order to assess the importance of the anthropogenic emissions of the marine and the coastal areas which are central for the economy of the Mediterranean Basin, we made a sensitivity test simulation. This simulation is similar to the reference simulation but with the removal of the international shipping emissions and the anthropogenic emissions over a 50 km wide band inland along the coast. We showed that around 30 % of the emissions of carbonaceous aerosols and 35 to 60 % of the exported carbonaceous aerosols originates from the marine and

  17. Inventory, distribution, and origin of aliphatic and polyaromatic hydrocarbons in sea water, the surface microlayer, and the aerosols in the tropical Eastern Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Marty, J C; Saliot, A; Tissier, M J

    1978-03-20

    Hydrocarbons have been analyzed in several samples from ''Midlante'' cruise, Cape Verde islands-Canary islands, in the Eastern tropical Atlantic: subsurface water, sea surface microlayer collected by a metallic screen and aerosols collected by filtration of large air volumes at about 12 m. above the sea surface. Detailed analysis of aliphatic and polyaromatic hydrocarbons has been made by computerized gas chromatography/mass spectrometry. This study of the air/sea interface indicates a discontinuity in hydrocarbon composition between the underlying water and the microlayer and a similarity between the surface microlayer and the aerosols. The origin of the collected aerosols is essentially marine with a minor terrestrial contribution. The hydrocarbon pattern shows that, superimposed on the typical marine components, a contribution from smokes of natural and industrial origin and/or from pollution associated with crude oil sea slicks is present.

  18. Aerosol Particles from Dried Salt-Lakes and Saline Soils Carried on Dust Storms over Beijing

    Directory of Open Access Journals (Sweden)

    Xingying Zhang

    2009-01-01

    Full Text Available Characteristics of individual particles from a super dust storm (DS on 20 March 2002, and those of non dust storm aero sols for Beijing (NDS and Duolun (DL (a desert area are determined using a variety of methods. In China, typically the source of aero sols in dust storms is thought to be deserts with alumino silicates being the main constituent particles; how ever, this does not reflect a complete analysis with our evidence indicating potential alternate dust sources along the storm's trans port path. Individual particle anal y sis of aero sols collected from a super dust storm on 20 March 2002 in Beijing shows that among all the 14 elements measured, only S and Cl have re mark able positive correlation. 82.5% of all particles measured contained both S and Cl, and the relative mass per cent age of S and Cl in these particles is much higher than the average of all particles. 62.0% of all particles contained S, Cl, and Na, in which the concentration of Na is 1.4 times higher than average. PMF (Positive Matrix Factorization anal y sis indicates that NaCl and Na2SO4 are major components of these particles with S and Cl showing significant positive correlation. More over, SO4 2- and Cl- also show significant positive correlation in bulk aero sol analysis. XPS (X-ray Pho to electron Spectros copy analysis of the surface of aero sols demonstrates that concentrations of Na and S on particles from the dust storm are higher than those from non-dust storm particles in Beijing and also for particles from. It is very likely that particles enriched with S, Cl, and Na is from the surface soils of dried salt-lakes and saline soils enriched with chloride and sulfate. This evidence demonstrates that be sides deserts, surface soils from dry salt-lakes and saline soils of arid and semi-arid areas are also sources of particulates in dust storms over Beijing.

  19. Inside versus Outside: Ion Redistribution in Nitric Acid Reacted Sea Spray Aerosol Particles as Determined by Single Particle Analysis (Invited)

    Science.gov (United States)

    Ault, A. P.; Guasco, T.; Ryder, O. S.; Baltrusaitis, J.; Cuadra-Rodriguez, L. A.; Collins, D. B.; Ruppel, M. J.; Bertram, T. H.; Prather, K. A.; Grassian, V. H.

    2013-12-01

    Sea spray aerosol (SSA) particles were generated under real-world conditions using natural seawater and a unique ocean-atmosphere facility equipped with actual breaking waves or a marine aerosol reference tank (MART) that replicates those conditions. The SSA particles were exposed to nitric acid in situ in a flow tube and the well-known chloride displacement and nitrate formation reaction was observed. However, as discussed here, little is known about how this anion displacement reaction affects the distribution of cations and other chemical constituents within and phase state of individual SSA particles. Single particle analysis of individual SSA particles shows that cations (Na+, K+, Mg2+ and Ca2+) within individual particles undergo a spatial redistribution after heterogeneous reaction with nitric acid, along with a more concentrated layer of organic matter at the surface of the particle. These data suggest that specific ion and aerosol pH effects play an important role in aerosol particle structure in ways that have not been previously recognized. The ordering of organic coatings can impact trace gas uptake, and subsequently impact trace gas budgets of O3 and NOx.

  20. Aerosol Retrievals Over Land and Water using Deep Blue Algorithm from SeaWiFS and MODIS during UAE2 Field Campaign

    Science.gov (United States)

    Hsu, N.

    2005-12-01

    The environment in Southwest Asia exhibits one of the most complex situations for aerosol remote sensing from space. Several air masses with different aerosol characteristics commonly converge in this region. In particular, there are often fine mode pollution particles generated from oil industry activities in the Persian Gulf colliding with coarse mode dust particles lifted from desert sources in the surrounding areas. During the course of the UAE field campaign (August-October, 2004), we provided near-real time information, calculated using the Deep Blue algorithm, of satellite aerosol optical thickness and Angstrom exponent over the Southwest Asia region, including the Arabian Peninsula, Iran, Afghanistan, Pakistan, and part of north Africa. In this paper, we will present results of aerosol characteristics retrieved from SeaWiFS and MODIS over the Arabian Peninsula, Persian Gulf, and the Arabian Sea during the UAE experiment. The spectral surface reflectance data base constructed using satellite reflectance from MODIS and SeaWiFS employed in our algorithm will be discussed. We will also compare the resulting satellite retrieved aerosol optical thickness and Angstrom exponent with those obtained from the ground based sun photometers from AERONET in the region. Finally, we will discuss the changes in shortwave and longwave fluxes at the top of atmosphere in response to changes in aerosol optical thickness (i.e. aerosol forcing).

  1. Distribution of trace gases and aerosols in the troposphere over West Siberia and Kara Sea

    Science.gov (United States)

    Belan, Boris D.; Arshinov, Mikhail Yu.; Paris, Jean-Daniel; Nédélec, Philippe; Ancellet, Gérard; Pelon, Jacques; Berchet, Antoine; Arzoumanian, Emmanuel; Belan, Sergey B.; Penner, Johannes E.; Balin, Yurii S.; Kokhanenko, Grigorii; Davydov, Denis K.; Ivlev, Georgii A.; Kozlov, Artem V.; Kozlov, Alexander S.; Chernov, Dmitrii G.; Fofonov, Alexader V.; Simonenkov, Denis V.; Tolmachev, Gennadii

    2015-04-01

    The Arctic is affected by climate change much stronger than other regions of the globe. Permafrost thawing can lead to additional methane release, which enhances the greenhouse effect and warming, as well as changes of Arctic tundra ecosystems. A great part of Siberian Arctic is still unexplored. Ground-based investigations are difficult to be carried out in this area due to it is an out-of-the-way place. So, in spite of the high cost, aircraft-based in-situ measurements can provide a good opportunity to fill up the gap in data on the atmospheric composition over this region. The ninth YAK-AEROSIB campaign was focused on the airborne survey of Arctic regions of West Siberia. It was performed in October 2014. During the campaign, the high-precision in-situ measurements of CO2, CH4, CO, O3, black carbon and aerososls, including aerosol lidar profiles, have been carried out in the Siberian troposphere from Novosibirsk to Kara Sea. Vertical distributions of the above atmospheric constituents will be presented. This work was supported by LIA YAK-AEROSIB, CNRS (France), the French Ministry of Foreign Affairs, CEA (France), the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); State contracts of the Ministry of Education and Science of Russia No. 14.604.21.0100, (RFMTFIBBB210290) and No. 14.613.21.0013 (RFMEFI61314X0013); Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; and Russian Foundation for Basic Research (grants No. 14-05-00526 and 14-05-00590).

  2. Spatially resolved micro-Raman observation on the phase separation of effloresced sea salt droplets.

    Science.gov (United States)

    Xiao, Han-Shuang; Dong, Jin-Ling; Wang, Liang-Yu; Zhao, Li-Jun; Wang, Feng; Zhang, Yun-Hong

    2008-12-01

    We report on the investigation of the phase separation of individual seawater droplets in the efflorescence processes with the spatially resolved Raman system. Upon decreasing the relative humidity (RH), CaSO4.0.5H2O separated out foremost fromthe droplet atan unexpectedly high RH of approcimately 90%. Occasionally, CaSO4.2H2O substituted for CaSO4.O.5H2O crystallizing first at approximately 78% RH. Relatively large NaCI solids followed to crystallize at approximately 55% RH and led to the great loss of the solution. Then, the KMgCl3.6H2O crystallites separated out from the residual solutions, adjacentto NaCl at approximately 44% RH. Moreover, a shell structure of dried sea salt particle was found to form at low RHs, with the NaCl crystals in the core and minor supersaturated solutions covered with MgSO4 gel coating on the surface. Ultimately, the shielded solution partly effloresced into MgSO4 hydrates at very dry state (<5% RH).

  3. Will fluctuations in salt marsh-mangrove dominance alter vulnerability of a subtropical wetland to sea-level rise?

    Science.gov (United States)

    McKee, Karen L; Vervaeke, William C

    2018-03-01

    To avoid submergence during sea-level rise, coastal wetlands build soil surfaces vertically through accumulation of inorganic sediment and organic matter. At climatic boundaries where mangroves are expanding and replacing salt marsh, wetland capacity to respond to sea-level rise may change. To compare how well mangroves and salt marshes accommodate sea-level rise, we conducted a manipulative field experiment in a subtropical plant community in the subsiding Mississippi River Delta. Experimental plots were established in spatially equivalent positions along creek banks in monospecific stands of Spartina alterniflora (smooth cordgrass) or Avicennia germinans (black mangrove) and in mixed stands containing both species. To examine the effect of disturbance on elevation dynamics, vegetation in half of the plots was subjected to freezing (mangrove) or wrack burial (salt marsh), which caused shoot mortality. Vertical soil development was monitored for 6 years with the surface elevation table-marker horizon system. Comparison of land movement with relative sea-level rise showed that this plant community was experiencing an elevation deficit (i.e., sea level was rising faster than the wetland was building vertically) and was relying on elevation capital (i.e., relative position in the tidal frame) to survive. Although Avicennia plots had more elevation capital, suggesting longer survival, than Spartina or mixed plots, vegetation type had no effect on rates of accretion, vertical movement in root and sub-root zones, or net elevation change. Thus, these salt marsh and mangrove assemblages were accreting sediment and building vertically at equivalent rates. Small-scale disturbance of the plant canopy also had no effect on elevation trajectories-contrary to work in peat-forming wetlands showing elevation responses to changes in plant productivity. The findings indicate that in this deltaic setting with strong physical influences controlling elevation (sediment accretion

  4. High pollution events in the Great Salt Lake Basin and its adjacent valleys. Insights on mechanisms and spatial distribution of the formation of secondary aerosol.

    Science.gov (United States)

    Franchin, A.; Middlebrook, A. M.; Baasandorj, M.; Brown, S. S.; Fibiger, D. L.; Goldberger, L.; McDuffie, E. E.; Moravek, A.; Murphy, J. G.; Thornton, J. A.; Womack, C.

    2017-12-01

    High pollution events are common in many locations in the U.S.A. and around the world. They can last several days or up to weeks and they negatively affect human health, deteriorate visibility, and increase premature mortality. The main causes for high pollution events are related to meteorology and sources. They often happen in the winter, when high emissions, stagnation and reduced mixing, due to a shallow boundary layer, cause high concentrations of pollutants to accumulate. In the last decades, the air quality in the U.S. has seen an overall improvement, due to the reductions in particulate and gaseous pollutants. However, some areas remain critical. The Great Salt Lake Basin and its adjacent valleys are currently areas where high pollution events are a serious environmental problem involving more than 2.4 million people. We will present the results of the Utah Wintertime Fine Particulate Study (UWFPS) that took place in winter 2017. During UWFPS, we carried out airborne measurements of aerosol chemical composition and precursor vapor concentrations over the Great Salt Lake Basin and its adjacent valleys. We will give insights into how and under which conditions conversion of precursor vapors into aerosol particles takes place in the area. We will also present a comparison of our measurements with models that will provide an insight of the mechanisms that lead to the formation of secondary aerosol particles. With the results of our work, we aim to inform strategies for pollution control in the future.

  5. Aerosol measurements over Southern Africa using LIDAR, satellite and sun-photometer

    CSIR Research Space (South Africa)

    Sivakumar, V

    2009-08-01

    Full Text Available .csir.co.za Dust Sea Salt Giant nuclei Natural Particles Chemical chemical condensables : SOA, H2SO4, HNO3 … nucleation condensation Aerosol Formation and processes Health Aerosols Solar Radiation Clouds Slide 3 © CSIR 2008 www....csir.co.za Emissions from Industries, vechicle and urban Volatile Components SO2, NOx, NH3, VOC Transformation Humidity and deposition of particules Primary Aerosols, BC, OC, Marine Salts, Natural resources 0 - 16 k m U p t o 50 k m 26 – 29...

  6. Impact of aerosol intrusions on sea-ice melting rates and the structure Arctic boundary layer clouds

    Science.gov (United States)

    Cotton, W.; Carrio, G.; Jiang, H.

    2003-04-01

    The Los Alamos National Laboratory sea-ice model (LANL CICE) was implemented into the real-time and research versions of the Colorado State University-Regional Atmospheric Modeling System (RAMS@CSU). The original version of CICE was modified in its structure to allow module communication in an interactive multigrid framework. In addition, some improvements have been made in the routines involved in the coupling, among them, the inclusion of iterative methods that consider variable roughness lengths for snow-covered ice thickness categories. This version of the model also includes more complex microphysics that considers the nucleation of cloud droplets, allowing the prediction of mixing ratios and number concentrations for all condensed water species. The real-time version of RAMS@CSU automatically processes the NASA Team SSMI F13 25km sea-ice coverage data; the data are objectively analyzed and mapped to the model grid configuration. We performed two types of cloud resolving simulations to assess the impact of the entrainment of aerosols from above the inversion on Arctic boundary layer clouds. The first series of numerical experiments corresponds to a case observed on May 4 1998 during the FIRE-ACE/SHEBA field experiment. Results indicate a significant impact on the microstructure of the simulated clouds. When assuming polluted initial profiles above the inversion, the liquid water fraction of the cloud monotonically decreases, the total condensate paths increases and downward IR tends to increase due to a significant increase in the ice water path. The second set of cloud resolving simulations focused on the evaluation of the potential effect of aerosol concentration above the inversion on melting rates during spring-summer period. For these multi-month simulations, the IFN and CCN profiles were also initialized assuming the 4 May profiles as benchmarks. Results suggest that increasing the aerosol concentrations above the boundary layer increases sea-ice melting

  7. Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

    OpenAIRE

    Schwier , A. N.; Rose , C.; Asmi , E.; Ebling , A. M.; Landing , W. M.; Marro , S.; Pedrotti , M.-L.; Sallon , A.; Iuculano , F.; Agusti , S.; Tsiola , A.; Pitta , P.; Louis , J.; Guieu , C.; Gazeau , F.

    2015-01-01

    The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of C...

  8. Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ model

    Directory of Open Access Journals (Sweden)

    J. T. Kelly

    2010-04-01

    Full Text Available Chemical processing of sea-salt particles in coastal environments significantly impacts concentrations of particle components and gas-phase species and has implications for human exposure to particulate matter and nitrogen deposition to sensitive ecosystems. Emission of sea-salt particles from the coastal surf zone is known to be elevated compared to that from the open ocean. Despite the importance of sea-salt emissions and chemical processing, the US EPA's Community Multiscale Air Quality (CMAQ model has traditionally treated coarse sea-salt particles as chemically inert and has not accounted for enhanced surf-zone emissions. In this article, updates to CMAQ are described that enhance sea-salt emissions from the coastal surf zone and allow dynamic transfer of HNO3, H2SO4, HCl, and NH3 between coarse particles and the gas phase. Predictions of updated CMAQ models and the previous release version, CMAQv4.6, are evaluated using observations from three coastal sites during the Bay Regional Atmospheric Chemistry Experiment (BRACE in Tampa, FL in May 2002. Model updates improve predictions of NO3, SO42−, NH4+, Na+, and Cl concentrations at these sites with only a 8% increase in run time. In particular, the chemically interactive coarse particle mode dramatically improves predictions of nitrate concentration and size distributions as well as the fraction of total nitrate in the particle phase. Also, the surf-zone emission parameterization improves predictions of total sodium and chloride concentration. Results of a separate study indicate that the model updates reduce the mean absolute error of nitrate predictions at coastal CASTNET and SEARCH sites in the eastern US. Although the new model features improve performance relative to CMAQv4.6, some persistent differences exist between observations and predictions

  9. Air-Sea exchange of biogenic volatile organic compounds and the impact on aerosol particle size distributions

    Science.gov (United States)

    Kim, Michelle J.; Novak, Gordon A.; Zoerb, Matthew C.; Yang, Mingxi; Blomquist, Byron W.; Huebert, Barry J.; Cappa, Christopher D.; Bertram, Timothy H.

    2017-04-01

    We report simultaneous, underway eddy covariance measurements of the vertical flux of isoprene, total monoterpenes, and dimethyl sulfide (DMS) over the Northern Atlantic Ocean during fall. Mean isoprene and monoterpene sea-to-air vertical fluxes were significantly lower than mean DMS fluxes. While rare, intense monoterpene sea-to-air fluxes were observed, coincident with elevated monoterpene mixing ratios. A statistically significant correlation between isoprene vertical flux and short wave radiation was not observed, suggesting that photochemical processes in the surface microlayer did not enhance isoprene emissions in this study region. Calculations of secondary organic aerosol production rates (PSOA) for mean isoprene and monoterpene emission rates sampled here indicate that PSOA is on average <0.1 μg m-3 d-1. Despite modest PSOA, low particle number concentrations permit a sizable role for condensational growth of monoterpene oxidation products in altering particle size distributions and the concentration of cloud condensation nuclei during episodic monoterpene emission events from the ocean.

  10. Bacillus isabeliae sp. nov., a halophilic bacterium isolated from a sea salt evaporation pond.

    Science.gov (United States)

    Albuquerque, Luciana; Tiago, Igor; Taborda, Marco; Nobre, M Fernanda; Veríssimo, António; da Costa, Milton S

    2008-01-01

    A low-G+C, Gram-positive isolate, designated strain CVS-8(T), was isolated from a sea salt evaporation pond on the Island of Sal in the Cape Verde Archipelago. This organism was found to be a catalase- and oxidase-positive, non-motile, spore-forming, aerobic, curved rod-shaped organism with an optimum growth temperature of about 35-37 degrees C and an optimum pH between 7.5 and 8.0. Optimal growth occurred in media containing 4-6% (w/v) NaCl and no growth occurred in medium without NaCl. The cell-wall peptidoglycan was of the A1gamma type with meso-diaminopimelic acid, the major respiratory quinone was MK-7, the major fatty acids were iso-15:0, 16:0, anteiso-15:0 and iso-16:0 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminoglycophospholipid. The G+C content of the DNA was 37.9 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain CVS-8(T) represented a novel species of the genus Bacillus, the highest levels of sequence similarity (mean pairwise similarity values of approximately 97.5 %) being found with respect to the type strains of Bacillus shackletonii and Bacillus acidicola. On the basis of the phylogenetic, physiological and biochemical data, strain CVS-8(T) represents a novel species of the genus Bacillus, for which the name Bacillus isabeliae sp. nov. is proposed. The type strain is CVS-8(T) (=LMG 22838(T)=CIP 108578(T)).

  11. The organic fraction of bubble-generated, accumulation mode Sea Spray Aerosol (SSA

    Directory of Open Access Journals (Sweden)

    R. L. Modini

    2010-03-01

    Full Text Available Recent studies have detected a dominant accumulation mode (~100 nm in the Sea Spray Aerosol (SSA number distribution. There is evidence to suggest that particles in this mode are composed primarily of organics. To investigate this hypothesis we conducted experiments on NaCl, artificial SSA and natural SSA particles with a Volatility-Hygroscopicity-Tandem-Differential-Mobility-Analyser (VH-TDMA. NaCl particles were atomiser generated and a bubble generator was constructed to produce artificial and natural SSA particles. Natural seawater samples for use in the bubble generator were collected from biologically active, terrestrially-affected coastal water in Moreton Bay, Australia. Differences in the VH-TDMA-measured volatility curves of artificial and natural SSA particles were used to investigate and quantify the organic fraction of natural SSA particles. Hygroscopic Growth Factor (HGF data, also obtained by the VH-TDMA, were used to confirm the conclusions drawn from the volatility data. Both datasets indicated that the organic fraction of our natural SSA particles evaporated in the VH-TDMA over the temperature range 170–200 °C. The organic volume fraction for 71–77 nm natural SSA particles was 8±6%. Organic volume fraction did not vary significantly with varying water residence time (40 s to 24 h in the bubble generator or SSA particle diameter in the range 38–173 nm. At room temperature we measured shape- and Kelvin-corrected HGF at 90% RH of 2.46±0.02 for NaCl, 2.35±0.02 for artifical SSA and 2.26±0.02 for natural SSA particles. Overall, these results suggest that the natural accumulation mode SSA particles produced in these experiments contained only a minor organic fraction, which had little effect on hygroscopic growth. Our measurement of 8±6% is an order of magnitude below two previous measurements of the organic fraction in SSA particles of comparable sizes. We stress that our results were obtained using coastal seawater and

  12. Aerosol properties over the Arabian Sea during the north east monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Dulac, F.; Leon, G.F.; Desa, E.

    Knowledge of the variations of the aerosol properties is essential for the development of the satellite atmospheric correction algorithms. The measurements were carried-out during a cruise using a six channel spectral sun photometer at wavelengths...

  13. Effect of sea salt irrigation on plant growth, yield potential and some biochemical attributes of carissa carandas

    International Nuclear Information System (INIS)

    Tayyab, A.

    2016-01-01

    Carissa carandas (varn. Karonda) is an edible and medicinal plant having ability to grow in saline and water deficit conditions, however, little is known about its salinity tolerance. Therefore, the effect of salinity on vegetative (height and volume), reproductive (number of flowers and number, size and weight of fruits) and some biochemical parameters (leaf pigments, ions, soluble sugars, proteins, and phenols) of C. carandas were studied. Plants were grown in drum pot culture and irrigated with non-saline or saline water of 0.6% and 0.8% sea salt concentrations, for a period of 30 months. Results showed that, plant height, and canopy volume decreased with increasing salinity. The chlorophyll contents and chlorophyll a/b ratio followed the similar trend as for growth, however, carotenoids increased at 0.6% sea salt and subsequently decreased in higher salinity. Unchanged soluble sugar and protein content at 0.6% sea salt, as compared to control, could be attributed to leaf osmotic adjustments which decreased with further increase in salinity. Linear increase in soluble phenols and carotenoid/chlorophyll ratio indicating a protective strategy of C. carandas to minimize photo-damage. Besides increasing Na+ and decreasing K+ contents, plant seemed to maintain K+/Na+ ratio (above 1), especially at 0.6 sea salt, which disturbed at higher salinity. Salinity adversely affected reproductive growth of C. carandas where, production of flowers, and fruits were significantly reduced. In addition, fresh and dry weights of fruits decreased with increasing salinity, but salinity did not affect fruit length and diameter. Present study provides basic information related to plant growth, fruit yield and some biochemical attributes, which suggest that C. carandas is moderately salt tolerant plant. This plant showed potential to grow on saline marginal lands using brackish water irrigation and provide biomass for edible and medicinal purposes. However, in-depth analysis of field and

  14. An assessment of the quality of aerosol retrievals over the Red Sea and evaluation of the climatological cloud-free dust direct radiative effect in the region

    KAUST Repository

    Brindley, H.

    2015-10-20

    Ground-based and satellite observations are used in conjunction with the Rapid Radiative Transfer Model (RRTM) to assess climatological aerosol loading and the associated cloud-free aerosol direct radiative effect (DRE) over the Red Sea. Aerosol optical depth (AOD) retrievals from the Moderate Resolution Imaging Spectroradiometer and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are first evaluated via comparison with ship-based observations. Correlations are typically better than 0.9 with very small root-mean-square and bias differences. Calculations of the DRE along the ship cruises using RRTM also show good agreement with colocated estimates from the Geostationary Earth Radiation Budget instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large particles. A monthly climatology of AOD over the Red Sea is then created from 5 years of SEVIRI retrievals. This shows enhanced aerosol loading and a distinct north to south gradient across the basin in the summer relative to the winter months. The climatology is used with RRTM to estimate the DRE at the top and bottom of the atmosphere and the atmospheric absorption due to dust aerosol. These climatological estimates indicate that although longwave effects can reach tens of W m−2, shortwave cooling typically dominates the net radiative effect over the Sea, being particularly pronounced in the summer, reaching 120 W m−2 at the surface. The spatial gradient in summertime AOD is reflected in the radiative effect at the surface and in associated differential heating by aerosol within the atmosphere above the Sea. This asymmetric effect is expected to exert a significant influence on the regional atmospheric and oceanic circulation.

  15. An assessment of the quality of aerosol retrievals over the Red Sea and evaluation of the climatological cloud-free dust direct radiative effect in the region

    KAUST Repository

    Brindley, H.; Osipov, Sergey; Bantges, R.; Smirnov, A.; Banks, J.; Levy, R.; Jish Prakash, P.; Stenchikov, Georgiy L.

    2015-01-01

    Ground-based and satellite observations are used in conjunction with the Rapid Radiative Transfer Model (RRTM) to assess climatological aerosol loading and the associated cloud-free aerosol direct radiative effect (DRE) over the Red Sea. Aerosol optical depth (AOD) retrievals from the Moderate Resolution Imaging Spectroradiometer and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) instruments are first evaluated via comparison with ship-based observations. Correlations are typically better than 0.9 with very small root-mean-square and bias differences. Calculations of the DRE along the ship cruises using RRTM also show good agreement with colocated estimates from the Geostationary Earth Radiation Budget instrument if the aerosol asymmetry parameter is adjusted to account for the presence of large particles. A monthly climatology of AOD over the Red Sea is then created from 5 years of SEVIRI retrievals. This shows enhanced aerosol loading and a distinct north to south gradient across the basin in the summer relative to the winter months. The climatology is used with RRTM to estimate the DRE at the top and bottom of the atmosphere and the atmospheric absorption due to dust aerosol. These climatological estimates indicate that although longwave effects can reach tens of W m−2, shortwave cooling typically dominates the net radiative effect over the Sea, being particularly pronounced in the summer, reaching 120 W m−2 at the surface. The spatial gradient in summertime AOD is reflected in the radiative effect at the surface and in associated differential heating by aerosol within the atmosphere above the Sea. This asymmetric effect is expected to exert a significant influence on the regional atmospheric and oceanic circulation.

  16. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yonghoon, E-mail: yhlee@mokpo.ac.kr [Department of Chemistry, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Ham, Kyung-Sik [Department of Food Engineering, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Han, Song-Hee [Division of Maritime Transportation System, Mokpo National Maritime University, Jeonnam 530-729 (Korea, Republic of); Yoo, Jonghyun, E-mail: jyoo@appliedspectra.com [Applied Spectra, Inc., 46665 Fremont Boulevard, Fremont, CA 94538 (United States); Jeong, Sungho [School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results. - Highlights: • Broadband LIBS spectra of various edible sea salts were obtained. • Intensity correlation of emission lines of the elements in edible sea salts was analyzed. • The elements were categorized into three groups with independent discriminating power. • The effective combination of a few lines can provide dependable classification models.

  17. Mixing states of aerosols over four environmentally distinct atmospheric regimes in Asia: coastal, urban, and industrial locations influenced by dust.

    Science.gov (United States)

    Ramachandran, S; Srivastava, Rohit

    2016-06-01

    Mixing can influence the optical, physical, and chemical characteristics of aerosols, which in turn can modify their life cycle and radiative effects. Assumptions on the mixing state can lead to uncertain estimates of aerosol radiative effects. To examine the effect of mixing on the aerosol characteristics, and their influence on radiative effects, aerosol mixing states are determined over four environmentally distinct locations (Karachi, Gwangju, Osaka, and Singapore) in Asia, an aerosol hot spot region, using measured spectral aerosol optical properties and optical properties model. Aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (g) exhibit spectral, spatial, and temporal variations. Aerosol mixing states exhibit large spatial and temporal variations consistent with aerosol characteristics and aerosol type over each location. External mixing of aerosol species is unable to reproduce measured SSA over Asia, thus providing a strong evidence that aerosols exist in mixed state. Mineral dust (MD) (core)-Black carbon (BC) (shell) is one of the most preferred aerosol mixing states. Over locations influenced by biomass burning aerosols, BC (core)-water soluble (WS, shell) is a preferred mixing state, while dust gets coated by anthropogenic aerosols (BC, WS) over urban regions influenced by dust. MD (core)-sea salt (shell) mixing is found over Gwangju corroborating the observations. Aerosol radiative forcing exhibits large seasonal and spatial variations consistent with features seen in aerosol optical properties and mixing states. TOA forcing is less negative/positive for external mixing scenario because of lower SSA. Aerosol radiative forcing in Karachi is a factor of 2 higher when compared to Gwangju, Osaka, and Singapore. The influence of g on aerosol radiative forcing is insignificant. Results emphasize that rather than prescribing one single aerosol mixing state in global climate models regionally and temporally varying aerosol

  18. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean – potential impacts

    Directory of Open Access Journals (Sweden)

    M. Astitha

    2010-07-01

    Full Text Available Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates, natural (desert dust, sea salt and chemically aged (sulphate and nitrate on dust aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment. The sodium (sea salt related aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  19. On the salt transport in the Cananéia sea during a spring tide experiment

    Directory of Open Access Journals (Sweden)

    Luiz Bruner de Miranda

    1996-01-01

    Full Text Available Observations of the velocity, salinity, water depths and tides in the southem region of the Cananéia Sea were sampled at an anchored station during two complete tidal cycles. The measurements were made during spring tides on 5-6 December, 1991. The observed non-tidal current profile for this weakly stratified tidal channel is found to be in close agreement with the results of a simple steady state unidimensional analytical model of a well-nuxed estuary. This comparison indicates that the primary driving mechanisms are the longitudinal salinity gradient and the fresh water discharge. The contribution to the advective salt transport is dominateô by the freshwater discharge through the down-stream non-tidal flow and the up-stream dispersive term due to Stokes wave transporto This dispersive term is almost one order of magnitude smaller than the down-stream non-tidãl transport inôuced bythe fresh water discharge. TidaI correlation, acting as a counter-dispersion term, and the steady shear dispersion term are two orders of magnitude smaller than the ôown-stream salt transporto The remaining dispersive terms, which are dependent on the deviations from the mean deptb, are smaller than eitlier of these terms by one order of magnitude. The computed total salt transport per unit width of a section perpendicular to the mean flow was in close agreement (within 12 % with the sum of the individual advective and dispersive terms. On the assumption that the tidal channel sampled is laterally homogeneous, an imoalance of the salt budget across the section was observed.Observações de velocidade, de salinidade, de profundidade e de maré na região sul do Mar de Cananéia foram realizadas numa estação fixa durante dois ciclos completos de maré. Essas medidas foram feitas durante maré de sizígia, no período de 5 a 6 de dezem6ro de 1991. A exame comparativo do perfil estacionário de velocidade desse sistema fracamente estratificado, indicou boa concord

  20. Evaluation of aerosol distributions in the GISS-TOMAS global aerosol microphysics model with remote sensing observations

    Directory of Open Access Journals (Sweden)

    Y. H. Lee

    2010-03-01

    Full Text Available The Aerosol Optical Depth (AOD and Angstrom Coefficient (AC predictions in the GISS-TOMAS model of global aerosol microphysics are evaluated against remote sensing data from MODIS, MISR, and AERONET. The model AOD agrees well (within a factor of two over polluted continental (or high sulfate, dusty, and moderate sea-salt regions but less well over the equatorial, high sea-salt, and biomass burning regions. Underprediction of sea-salt in the equatorial region is likely due to GCM meteorology (low wind speeds and high precipitation. For the Southern Ocean, overprediction of AOD is very likely due to high sea-salt emissions and perhaps aerosol water uptake in the model. However, uncertainties in cloud screening at high latitudes make it difficult to evaluate the model AOD there with the satellite-based AOD. AOD in biomass burning regions is underpredicted, a tendency found in other global models but more severely here. Using measurements from the LBA-SMOCC 2002 campaign, the surface-level OC concentration in the model are found to be underpredicted severely during the dry season while much less severely for EC concentration, suggesting the low AOD in the model is due to underpredictions in OM mass. The potential for errors in emissions and wet deposition to contribute to this bias is discussed.

  1. Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

    Science.gov (United States)

    Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

    2004-01-01

    During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

  2. Under-ice eddy covariance flux measurements of heat, salt, momentum, and dissolved oxygen in an artificial sea ice pool

    DEFF Research Database (Denmark)

    Else, B. G T; Rysgaard, S.; Attard, K.

    2015-01-01

    as one possible cause of the high fluxes. Momentum fluxes showed interesting correlations with ice growth and melt but were generally higher than expected. We concluded that with the exception of the conductivity sensor, the eddy covariance system worked well, and that useful information about turbulent......Turbulent exchanges under sea ice play a controlling role in ice mass balance, ice drift, biogeochemistry, and mixed layer modification. In this study, we examined the potential to measure under-ice turbulent exchanges of heat, salt, momentum, and dissolved oxygen using eddy covariance...... in an experimental sea ice facility. Over a 15-day period in January 2013, an underwater eddy covariance system was deployed in a large (500 m3) inground concrete pool, which was filled with artificial seawater and exposed to the ambient (−5 to −30 °C) atmosphere. Turbulent exchanges were measured continuously...

  3. Effects of the North Atlantic Oscillation and wind waves on salt marsh dynamics in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Kim, Daehyun; Grant, William E.; Cairns, David M.

    2013-01-01

    Long-term eustatic sea-level variation has been recognized as a primary factor affecting the hydrological and geomorphic dynamics of salt marshes. However, recent studies suggest that wind waves influenced by atmospheric oscillations also may play an important role in many coastal areas. Although...... this notion has been conceptually introduced for the Wadden Sea, no modeling attempts have been made yet. As a proof of concept, this study developed a simulation model using the commercially available STELLAA (R) software, based on long-term data on water level and sedimentation collected at a back......-barrier marsh on the Skallingen peninsula in Denmark. In the model, the frequency (number year(-1)) of wind-driven extreme high water level (HWL) events (> 130 cm Danish Ordnance Zero) was simulated in terms of the North Atlantic Oscillation (NAO) index. Then, surface accretion (cm year(-1)) and submergence...

  4. Exploring mechanisms of compaction in salt-marsh sediments using Common Era relative sea-level reconstructions

    Science.gov (United States)

    Brain, Matthew J.; Kemp, Andrew C.; Hawkes, Andrea D.; Engelhart, Simon E.; Vane, Christopher H.; Cahill, Niamh; Hill, Troy D.; Donnelly, Jeffrey P.; Horton, Benjamin P.

    2017-07-01

    Salt-marsh sediments provide precise and near-continuous reconstructions of Common Era relative sea level (RSL). However, organic and low-density salt-marsh sediments are prone to compaction processes that cause post-depositional distortion of the stratigraphic column used to reconstruct RSL. We compared two RSL reconstructions from East River Marsh (Connecticut, USA) to assess the contribution of mechanical compression and biodegradation to compaction of salt-marsh sediments and their subsequent influence on RSL reconstructions. The first, existing reconstruction ('trench') was produced from a continuous sequence of basal salt-marsh sediment and is unaffected by compaction. The second, new reconstruction is from a compaction-susceptible core taken at the same location. We highlight that sediment compaction is the only feasible mechanism for explaining the observed differences in RSL reconstructed from the trench and core. Both reconstructions display long-term RSL rise of ∼1 mm/yr, followed by a ∼19th Century acceleration to ∼3 mm/yr. A statistically-significant difference between the records at ∼1100 to 1800 CE could not be explained by a compression-only geotechnical model. We suggest that the warmer and drier conditions of the Medieval Climate Anomaly (MCA) resulted in an increase in sediment compressibility during this time period. We adapted the geotechnical model by reducing the compressive strength of MCA sediments to simulate this softening of sediments. 'Decompaction' of the core reconstruction with this modified model accounted for the difference between the two RSL reconstructions. Our results demonstrate that compression-only geotechnical models may be inadequate for estimating compaction and post-depositional lowering of susceptible organic salt-marsh sediments in some settings. This has important implications for our understanding of the drivers of sea-level change. Further, our results suggest that future climate changes may make salt

  5. Heterogeneity in pre-monsoon aerosol types over the Arabian Sea deduced from ship-borne measurements of spectral AODs

    Directory of Open Access Journals (Sweden)

    D. G. Kaskaoutis

    2010-05-01

    Full Text Available Ship-borne sunphotometer measurements obtained in the Arabian Sea (AS in the pre-monsoon season (18 April–10 May 2006 during a cruise campaign (ICARB have been used to retrieve the Aerosol Optical Depth (AOD; τ and the Ångström wavelength exponent (α. The continents surrounding the AS produce natural and anthropogenic aerosols that have distinctive influences on α and its spectral distribution. The α values were estimated by means of the least-squares method over the spectral bands 340–1020 nm and 340–870 nm. The spectral distribution of AOD in logarithmic co-ordinates could be fit using a 2nd order polynomial with higher accuracy in the wavelength band 340–1020 nm than in the 340–870 nm band. A polynomial fit analytically parameterizes the observed wavelength dependencies of AOD with least errors in spectral variation of α and yields accurate estimates of the coefficients (a1 and a2. The coarse-mode (positive curvature in the lnτλ vs. lnλ aerosols are mainly depicted in the Northern part of the AS closely associated with the nearby arid areas while fine-mode aerosols are mainly observed over the far and coastal AS regions. In the study period the mean AOD at 500 nm is 0.25±0.11 and the α340-1020 is 0.90±0.19. The α340-870 exhibits similar values (0.92±0.18, while significant differences revealed for the constant terms of the polynomial fit (a1 and a2 proportionally to the wavelength band used for their determination. Observed day-to-day variability in the aerosol load and optical properties are direct consequence of the local winds and air-mass trajectories along with the position of the ship.

  6. Operational aerosol and dust storm forecasting

    International Nuclear Information System (INIS)

    Westphal, D L; Curtis, C A; Liu, M; Walker, A L

    2009-01-01

    The U. S. Navy now conducts operational forecasting of aerosols and dust storms on global and regional scales. The Navy Aerosol Analysis and Prediction System (NAAPS) is run four times per day and produces 6-day forecasts of sulfate, smoke, dust and sea salt aerosol concentrations and visibility for the entire globe. The Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS (registered) ) is run twice daily for Southwest Asia and produces 3-day forecasts of dust, smoke, and visibility. The graphical output from these models is available on the Internet (www.nrlmry.navy.mil/aerosol/). The aerosol optical properties are calculated for each specie for each forecast output time and used for sea surface temperature (SST) retrieval corrections, regional electro-optical (EO) propagation assessments, and the development of satellite algorithms. NAAPS daily aerosol optical depth (AOD) values are compared with the Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD values. Visibility forecasts are compared quantitatively with surface synoptic reports.

  7. Aerosol Radiative Impact on the Middle East Regional Climate and the Red Sea

    KAUST Repository

    Osipov, Sergey

    2017-01-01

    The climate in the Middle East is complex and remains poorly understood. Due to the vast Arabian Desert, it is very sensitive to radiative forcing. Mineral dust is the dominant aerosol in this region. High background dust loading and frequent dust

  8. Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Menon, H.B.; Sangekar, N.; Lotliker, A.; Moorthy, K.K.; Vethamony, P.

    for water-leaving radiance and sun glint to the NIR bands. The aerosol size distribution parameter (alpha) was derived from a relationship between two NIR bands. The Angstrom turbidity parameter (beta) was obtained using an algorithm relating in situ hand...

  9. Thermodynamic versus non-equilibrium stability of palmitic acid monolayers in calcium-enriched sea spray aerosol proxy systems.

    Science.gov (United States)

    Wellen Rudd, Bethany A; Vidalis, Andrew S; Allen, Heather C

    2018-04-16

    Of the major cations in seawater (Na+, Mg2+, Ca2+, K+), Ca2+ is found to be the most enriched in fine sea spray aerosols (SSA). In this work, we investigate the binding of Ca2+ to the carboxylic acid headgroup of palmitic acid (PA), a marine-abundant fatty acid, and the impact such binding has on the stability of PA monolayers in both equilibrium and non-equilibrium systems. A range of Ca2+ conditions from 10 μM to 300 mM was utilized to represent the relative concentration of Ca2+ in high and low relative humidity aerosol environments. The CO2- stretching modes of PA detected by surface-sensitive infrared reflection-absorption spectroscopy (IRRAS) reveal ionic binding motifs of the Ca2+ ion to the carboxylate group with varying degrees of hydration. Surface tensiometry was used to determine the thermodynamic equilibrium spreading pressure (ESP) of PA on the various aqueous CaCl2 subphases. Up to concentrations of 1 mM Ca2+, each system reached equilibrium, and Ca2+:PA surface complexation gave rise to a lower energy state revealed by elevated surface pressures relative to water. We show that PA films are not thermodynamically stable at marine aerosol-relevant Ca2+ concentrations ([Ca2+] ≥ 10 mM). IRRAS and vibrational sum frequency generation (VSFG) spectroscopy were used to investigate the surface presence of PA on high concentration Ca2+ aqueous subphases. Non-equilibrium relaxation (NER) experiments were also conducted and monitored by Brewster angle microscopy (BAM) to determine the effect of the Ca2+ ions on PA stability. At high surface pressures, the relaxation mechanisms of PA varied among the systems and were dependent on Ca2+ concentration.

  10. Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS BASELInE

    Science.gov (United States)

    Tsay, Si-Chee; Maring, Hal B.; Lin, Neng-Huei; Buntoung, Sumaman; Chantara, Somporn; Chuang, Hsiao-Chi; Gabriel, Philip M.; Goodloe, Colby S.; Holben, Brent N.; Hsiao, Ta-Chih; hide

    2016-01-01

    The objectives of 7-SEASBASELInE (Seven SouthEast Asian Studies Biomass-burning Aerosols and Stratocumulus Environment: Lifecycles and Interactions Experiment) campaigns in spring 2013-2015 were to synergize measurements from uniquely distributed ground-based networks (e.g., AERONET (AErosol RObotic NETwork)), MPLNET ( NASA Micro-Pulse Lidar Network)) and sophisticated platforms (e.g.,SMARTLabs (Surface-based Mobile Atmospheric Research and Testbed Laboratories), regional contributing instruments), along with satellite observations retrievals and regional atmospheric transport chemical models to establish a critically needed database, and to advance our understanding of biomass-burning aerosols and trace gases in Southeast Asia (SEA). We present a satellite-surface perspective of 7-SEASBASELInE and highlight scientific findings concerning: (1) regional meteorology of moisture fields conducive to the production and maintenance of low-level stratiform clouds over land; (2) atmospheric composition in a biomass-burning environment, particularly tracers-markers to serve as important indicators for assessing the state and evolution of atmospheric constituents; (3) applications of remote sensing to air quality and impact on radiative energetics, examining the effect of diurnal variability of boundary-layer height on aerosol loading; (4) aerosol hygroscopicity and ground-based cloud radar measurements in aerosol-cloud processes by advanced cloud ensemble models; and (5) implications of air quality, in terms of toxicity of nanoparticles and trace gases, to human health. This volume is the third 7-SEAS special issue (after Atmospheric Research, vol. 122, 2013; and Atmospheric Environment, vol. 78, 2013) and includes 27 papers published, with emphasis on air quality and aerosol-cloud effects on the environment. BASELInE observations of stratiform clouds over SEA are unique, such clouds are embedded in a heavy aerosol-laden environment and feature characteristically greater

  11. Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2010-12-01

    Full Text Available Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm and coarse particles (D_p>2.0 μm increased during the winter-spring. The range of CN concentration was 30-2200 cm^ near the surface (surface-500 m and 7-7250 cm^ in the lower free troposphere (>1500 m. During the austral summer, higher CN concentration was often observed in the lower free troposphere. Frequent appearance of higher CN concentration in the free troposphere relative to the surface measurements strongly suggests that new particle formation in the Antarctic regions occurs in the lower free troposphere. Single particle analysis indicated that most of the aerosol particles during the winter were composed of Mg-enriched sea-salt particles originated from sea-salt fractionation on the sea-ice and their modified particles by NO_3^ and SO_4^. This suggests that sea-salt fractionation on sea-ice and modification of sea-salt particles were affected greatly by aerosol hygroscopicity during the winter. Antarctic haze layer was observed not only in the boundary layer but also in the lower free troposphere.

  12. Inland Sea Spray Aerosol Transport and Incomplete Chloride Depletion: Varying Degrees of Reactive Processing Observed during SOAS

    Energy Technology Data Exchange (ETDEWEB)

    Bondy, Amy L. [Department; Wang, Bingbing [Environmental; Laskin, Alexander [Environmental; Craig, Rebecca L. [Department; Nhliziyo, Manelisi V. [Department; Bertman, Steven B. [Department; Pratt, Kerri A. [Department; Shepson, Paul B. [Departments; Ault, Andrew P. [Department; Department

    2017-08-08

    Multiphase reactions involving sea spray aerosol (SSA) impact trace gases budgets in coastal regions by acting as a reservoir for oxidized nitrogen and sulfur species, as well as a source of halogen gases (HCl, ClNO2, etc.). While most studies of multiphase reactions on SSA have focused on marine environments, far less is known about SSA transported inland. Herein, single particle measurements of SSA are reported at a site > 320 km from the Gulf of Mexico, with transport times of 7-68 h. Samples were collected during the Southern Oxidant and Aerosol Study (SOAS) in June-July 2013 near Centreville, Alabama. SSA was observed in 93% of 42 time periods analyzed. During two marine air mass periods, SSA represented significant number fractions of particles in the accumulation (0.2-1.0 μm, 11%) and coarse (1.0-10.0 μm, 35%) modes. Chloride content of SSA particles ranged from full to partial depletion, with 24% of SSA particles containing chloride (mole fraction of Cl/Na > 0.1, 90% chloride depletion). Both the frequent observation of SSA at an inland site and the range of chloride depletion observed, suggest that SSA may represent an underappreciated inland sink for NOx/SO2 and source of halogen gases.

  13. Coarse mode aerosols in the High Arctic

    Science.gov (United States)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

    2014-12-01

    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  14. Platyamoeba pseudovannellida n. sp., a naked amoeba with wide salt tolerance isolated from the Salton Sea, California.

    Science.gov (United States)

    Hauer, G; Rogerson, A; Anderson, O R

    2001-01-01

    A new species of naked amoeba, Platyamoeba pseudovannellida n.sp., is described on the basis of light microscopic and fine structural features. The amoeba was isolated from the Salton Sea, California, from water at a salinity of ca. 44%. Locomotive amoebae occasionally had a spatulate outline and floating cells had radiating pseudopodia, sometimes with pointed tips. Both these features are reminiscent of the genus Vannella. However, the surface coat (glycocalyx) as revealed by TEM indicates that this is a species of Platyamoeba. Although salinity was not used as a diagnostic feature, this species was found to have remarkable tolerance to fluctuating salinity levels, even when changes were rapid. Amoebae survived over the range 0 per thousand to 150 per thousand salt and grew within the range 0 per thousand to 138 per thousand salt. The generation time of cells averaged 29 h and was not markedly affected by salt concentration. This is longer than expected for an amoeba of this size and suggests a high energetic cost of coping with salinity changes. The morphology of cells changed with increasing salinity: at 0 per thousand cells were flattened and active and at the other extreme (138 per thousand) amoebae were wrinkled and domed and cell movement was very slow. At the ultrastructural level, the cytoplasm of cells grown at high salinity (98 per thousand was considerably denser than that of cells reared at 0 per thousand.

  15. Temporal variation of accumulation rates on a natural salt marsh in the 20th century determined by 137Cs chronologies – the impact of sea level rise and increased inundation frequency

    DEFF Research Database (Denmark)

    Andersen, Thorbjørn Joest; Svinth, Steffen; Pejrup, Morten

    2011-01-01

    Salt marshes are potentially threatened by sea level rise if sediment supply is unable to balance the rising sea. A rapid sea level rise is one of the pronounced effects of global warming and global sea level is at present rising at an elevated rate of about 3.4 mm y-1 on average. This increasing...... in sediment deposition is significant and gives reason for concern as it may be the first sign of a sedimentation deficiency which could be threatening this and other salt marshes in the case of a rapidly rising sea level. Our work demonstrates that the assumption of a constant relationship between salt marsh...... with salt marsh accretion is most probably not valid in the present case study and it may well be that this is also the case for many other salt marshes, especially if sea level continues to rise rapidly as indicated by some climate change scenarios....

  16. Technical Report Series on Global Modeling and Data Assimilation. Volume 32; Estimates of AOD Trends (2002 - 2012) Over the World's Major Cities Based on the MERRA Aerosol Reanalysis

    Science.gov (United States)

    Provencal, Simon; Kishcha, Pavel; Elhacham, Emily; daSilva, Arlindo M.; Alpert, Pinhas; Suarez, Max J.

    2014-01-01

    NASA's Global Modeling and Assimilation Office has extended the Modern-Era Retrospective Analysis for Research and Application (MERRA) tool with five atmospheric aerosol species (sulfates, organic carbon, black carbon, mineral dust and sea salt). This inclusion of aerosol reanalysis data is now known as MERRAero. This study analyses a ten-year period (July 2002 - June 2012) MERRAero aerosol reanalysis applied to the study of aerosol optical depth (AOD) and its trends for the aforementioned aerosol species over the world's major cities (with a population of over 2 million inhabitants). We found that a proportion of various aerosol species in total AOD exhibited a geographical dependence. Cities in industrialized regions (North America, Europe, central and eastern Asia) are characterized by a strong proportion of sulfate aerosols. Organic carbon aerosols are dominant over cities which are located in regions where biomass burning frequently occurs (South America and southern Africa). Mineral dust dominates other aerosol species in cities located in proximity to the major deserts (northern Africa and western Asia). Sea salt aerosols are prominent in coastal cities but are dominant aerosol species in very few of them. AOD trends are declining over cities in North America, Europe and Japan, as a result of effective air quality regulation. By contrast, the economic boom in China and India has led to increasing AOD trends over most cities in these two highly-populated countries. Increasing AOD trends over cities in the Middle East are caused by increasing desert dust.

  17. Salt additions increase soil nitrate leaching: Implications for near-coastal watershed biogeochemistry

    Science.gov (United States)

    Deposition of sea salt aerosols is often elevated along the coast relative to inland areas, yet little is known about the effects of this deposition on terrestrial ecosystem biogeochemistry. Spatial patterns of stream chemistry in the Oregon Coast Range led us to hypothesize tha...

  18. The Dead Sea: A model of a desiccating terminal salt lake

    International Nuclear Information System (INIS)

    Gat, J.R.

    2001-01-01

    The continuing decline in the water level of the Dead Sea and the commensurate increase in salinity and precipitation of evaporates results in an irreversible evolution of the structure of the sea. The Dead Sea has been switching from its holomictic regime to short meromictic phases of up to 4-year duration, following the particular rainy winters of 1980 and 1992. The massive precipitation of halite in recent years, as well as the re-introduction of the end-brines of the potash plant, is changing the ion composition of the Dead Sea waters. This necessitates the adjustment of the equation-of-state of the brine and the solubility curve of halite. One consequence is that the onset of halite precipitation during the summer occurs earlier and earlier in the annual cycle. New isotopic measurement of δ 37 Cl of the brine and evaporate deposits and of δ 18 O in dissolved oxygen in the water column have yielded new information on geochemical processes in the Dead Sea system. A systematic monitoring of the oxygen and hydrogen isotopes in the Dead Sea waters has, unfortunately, not been continued in recent years and should be encouraged for the future. (author)

  19. Sub-Antarctic marine aerosol: dominant contributions from biogenic sources

    Directory of Open Access Journals (Sweden)

    J. Schmale

    2013-09-01

    Full Text Available Biogenic influences on the composition and characteristics of aerosol were investigated on Bird Island (54°00' S, 38°03' W in the South Atlantic during November and December 2010. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particles, measured by an aerosol mass spectrometer (AMS, was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA profiles could be isolated: an amino acid/amine factor (AA-OA, 18% of OA mass, a methanesulfonic acid OA factor (MSA-OA, 25%, a marine oxygenated OA factor (M-OOA, 41%, a sea spray OA fraction (SS-OA, 7% and locally produced hydrocarbon-like OA (HOA, 9%. The AA-OA was dominant during the first two weeks of November and found to be related with the hatching of penguins in a nearby colony. This factor, rich in nitrogen (N : C ratio = 0.13, has implications for the biogeochemical cycling of nitrogen in the area as particulate matter is often transported over longer distances than gaseous N-rich compounds. The MSA-OA was mainly transported from more southerly latitudes where phytoplankton bloomed. The bloom was identified as one of three sources for particulate sulfate on Bird Island, next to sea salt sulfate and sulfate transported from South America. M-OOA was the dominant organic factor and found to be similar to marine OA observed at Mace Head, Ireland. An additional OA factor highly correlated with sea spray aerosol was identified (SS-OA. However, based on the available data the type of mixture, internal or external, could not be determined. Potassium was not

  20. Final Report for “Simulating the Arctic Winter Longwave Indirect Effects. A New Parameterization for Frost Flower Aerosol Salt Emissions” (DESC0006679) for 9/15/2011 through 9/14/2015

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Lynn M. [Univ. of California, San Diego, CA (United States); Somerville, Richard C.J. [Univ. of California, San Diego, CA (United States); Burrows, Susannah [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rasch, Phil [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-12

    Description of the Project: This project has improved the aerosol formulation in a global climate model by using innovative new field and laboratory observations to develop and implement a novel wind-driven sea ice aerosol flux parameterization. This work fills a critical gap in the understanding of clouds, aerosol, and radiation in polar regions by addressing one of the largest missing particle sources in aerosol-climate modeling. Recent measurements of Arctic organic and inorganic aerosol indicate that the largest source of natural aerosol during the Arctic winter is emitted from crystal structures, known as frost flowers, formed on a newly frozen sea ice surface [Shaw et al., 2010]. We have implemented the new parameterization in an updated climate model making it the first capable of investigating how polar natural aerosol-cloud indirect effects relate to this important and previously unrecognized sea ice source. The parameterization is constrained by Arctic ARM in situ cloud and radiation data. The modified climate model has been used to quantify the potential pan-Arctic radiative forcing and aerosol indirect effects due to this missing source. This research supported the work of one postdoc (Li Xu) for two years and contributed to the training and research of an undergraduate student. This research allowed us to establish a collaboration between SIO and PNNL in order to contribute the frost flower parameterization to the new ACME model. One peer-reviewed publications has already resulted from this work, and a manuscript for a second publication has been completed. Additional publications from the PNNL collaboration are expected to follow.

  1. Interplay of salt dynamics, sea-level change and climate on the depositional evolution of a Paleogene economic coal bearing salt rim syncline, Schoeningen, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Osman, A.; Pollok, L.; Brandes, C.; Winsemann, J. [Leibniz Univ. Hannover (Germany). Inst. fuer Geologie

    2013-08-01

    The Paleogene basin fill (maximum 300 m thick) of the Schoeningen rim syncline in northern Germany is well known for its economic lignitic coal deposits. The fill provides an example of the interaction of basin subsidence, sea-level, and climate changes on depositional environment and gives insight into the development of the coal seams within a sequence stratigraphic context. The rim syncline records thirteen Lower to Middle Eocene coal seams with intervening clastic layers that were deposited during a long-lived transgression of the Central German Estuary, which lasted until the Late Oligocene (Standke, 2008). The previous analysis of the rim syncline fill has primarily focused on coal deposits, their lateral extent and paleo-botanical habitat. In this work, 357 lithologic logs were calibrated to outcrop profiles and integrated with previous studies to provide a facies analysis and sequence stratigraphy interpretation of the syncline fill. This improves understanding of the depositional environments of the lesser-studied clastics that intervene the coals (Osman et al., in review). Four 3{sup rd} order sequences are recorded in the Lower to Middle Eocene basin fill. Sequences 1 and 2 document the interplay of sands and coals within a transgressive estuarine phase. The sands show a regime change from tide- to more wave-dominated estuarine conditions before a turnaround to a regressive deltaic phase. This succession typifies an incised valley fill. However, the accommodation space generated for the initial estuary development is thought to have originated via continual salt withdrawal (Brandes et al. 2012) instead of by incision during relative sea-level fall. The observed tide to wave estuary regime change is linked to increased subsidence rates at 57 Ma that generated a higher tidal prism. As the subsidence rates slowed and the syncline broadened, the tidal prism decreased, leading to the development of more wave-dominated facies. The intervening coal seams

  2. On-site ocean horizontal aerosol extinction coefficient inversion under different weather conditions on the Bo-hai and Huang-hai Seas

    Science.gov (United States)

    Zeng, Xianjiang; Xia, Min; Ge, Yinghui; Guo, Wenping; Yang, Kecheng

    2018-03-01

    In this paper, we explore the horizontal extinction characteristics under different weather conditions on the ocean surface with on-site experiments on the Bo-hai and Huang-hai Seas in the summer of 2016. An experimental lidar system is designed to collect the on-site experimental data. By aiming at the inhomogeneity and uncertainty of the horizontal aerosol in practice, a joint retrieval method is proposed to retrieve the aerosol extinction coefficients (AEC) from the raw data along the optical path. The retrieval results of both the simulated and the real signals demonstrate that the joint retrieval method is practical. Finally, the sequence observation results of the on-site experiments under different weather conditions are reported and analyzed. These results can provide the attenuation information to analyze the atmospheric aerosol characteristics on the ocean surface.

  3. Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.

    Science.gov (United States)

    Nelson, Joanna L; Zavaleta, Erika S

    2012-01-01

    Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4)NO(3))-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication.

  4. Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.

    Directory of Open Access Journals (Sweden)

    Joanna L Nelson

    Full Text Available Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4NO(3-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a aboveground biomass, b plant tissue N concentrations, c N stock sequestered in plants, and d shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication.

  5. Trace determination of heavy metal concentrations in fauna, flora and salt samples from Black Sea waters by charged particles - induced X-rays

    International Nuclear Information System (INIS)

    Badica, T.; Ciortea, C.; Dima, S.; Petrovici, A.; Popescu, I.; Serbanescu, O.

    1977-01-01

    Studies were performed on Black Sea pollution by charged particles induced X-rays spectra analysis, using alpha and 16 O beams. Fauna, flora and salt samples were analysed. We found some of the concentrations of pollutant elements to be below the accepted levels. (author)

  6. Nutrient enrichment and precipitation changes do not enhance resiliency of salt marshes to sea level rise in the Northeastern U.S.

    Science.gov (United States)

    In the U.S. Northeast, salt marshes are exceptionally vulnerable to the effects of accelerated sea level rise as compensatory mechanisms relying on positive feedbacks between inundation and sediment deposition are insufficient to counter inundation increases in low turbidity tida...

  7. Direct radiative forcing due to aerosols in Asia during March 2002.

    Science.gov (United States)

    Park, Soon-Ung; Jeong, Jaein I

    2008-12-15

    The Asian dust aerosol model (ADAM) and the aerosol dynamic model including the gas-aerosol interaction processes together with the Column Radiation Model (CRM) of Community Climate Model 3 and the output of the fifth generation of meso-scale model (MM5) in a grid 60 x 60 km2 in the Asian domain (70-150E, Equator-50N) have been employed to estimate direct radiative forcing of the Asian dust and the anthropogenic aerosols including the BC, OC, secondary inorganic aerosol (SIA), mixed type aerosol (dust+BC+OC+SIA) and sea salt aerosols at the surface, the top of atmosphere (TOA) and in the atmosphere for the period of 1-31 March 2002 during which a severe Asian dust event has been occurred in the model domain. The results indicate that the ADAM model and the aerosol dynamic model simulate quite well the spatial and temporal distributions of the mass concentration of aerosols with the R2 value of more than 0.7. The estimated mean total column aerosol mass in the analysis domain for the whole period is found to be about 78 mg m(-2), of which 66% and 34% are, respectively, contributed by the Asian dust aerosol and all the other anthropogenic aerosols. However, the direct radiative forcing contributed by the Asian dust aerosol is about 22% of the mean radiative forcing at the surface (-6.8 W m(-2)), about 31% at the top of atmosphere (-2.9 W m(-2)) and about 13% in the atmosphere (3.8 W m(-2)), suggesting relatively inefficient contribution of the Asian dust aerosol on the direct radiative forcing compared to the anthropogenic aerosols. The aerosol direct radiative forcing at the surface is mainly contributed by the mixed type aerosol (30%) and the SIA aerosol (25%) while at the top of atmosphere it is mainly contributed by the SIA aerosol (43%) and the Asian dust aerosol (31%) with positively (warming) contributed by BC and mixed type aerosols. The atmosphere is warmed mainly by the mixed type aerosol (55%) and the BC aerosol (26%). However, the largest radiative

  8. Direct radiative forcing due to aerosols in Asia during March 2002

    International Nuclear Information System (INIS)

    Park, Soon-Ung; Jeong, Jaein I.

    2008-01-01

    The Asian dust aerosol model (ADAM) and the aerosol dynamic model including the gas-aerosol interaction processes together with the Column Radiation Model (CRM) of Community Climate Model 3 and the output of the fifth generation of meso-scale model (MM5) in a grid 60 x 60 km 2 in the Asian domain (70-150E, Equator-50N) have been employed to estimate direct radiative forcing of the Asian dust and the anthropogenic aerosols including the BC, OC, secondary inorganic aerosol (SIA), mixed type aerosol (dust + BC + OC + SIA) and sea salt aerosols at the surface, the top of atmosphere (TOA) and in the atmosphere for the period of 1-31 March 2002 during which a severe Asian dust event has been occurred in the model domain. The results indicate that the ADAM model and the aerosol dynamic model simulate quite well the spatial and temporal distributions of the mass concentration of aerosols with the R 2 value of more than 0.7. The estimated mean total column aerosol mass in the analysis domain for the whole period is found to be about 78 mg m -2 , of which 66% and 34% are, respectively, contributed by the Asian dust aerosol and all the other anthropogenic aerosols. However, the direct radiative forcing contributed by the Asian dust aerosol is about 22% of the mean radiative forcing at the surface (- 6.8 W m -2 ), about 31% at the top of atmosphere (- 2.9 W m -2 ) and about 13% in the atmosphere (3.8 W m -2 ), suggesting relatively inefficient contribution of the Asian dust aerosol on the direct radiative forcing compared to the anthropogenic aerosols. The aerosol direct radiative forcing at the surface is mainly contributed by the mixed type aerosol (30%) and the SIA aerosol (25%) while at the top of atmosphere it is mainly contributed by the SIA aerosol (43%) and the Asian dust aerosol (31%) with positively (warming) contributed by BC and mixed type aerosols. The atmosphere is warmed mainly by the mixed type aerosol (55%) and the BC aerosol (26%). However, the largest

  9. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    International Nuclear Information System (INIS)

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365 0 C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables

  10. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    Science.gov (United States)

    Elders, W. A.; Cohen, L. H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 3650C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high conentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it.

  11. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  12. Evaluating Humidity and Sea Salt Disturbances on CO2 Flux Measurements

    DEFF Research Database (Denmark)

    Nilsson, Erik; Bergström, Hans; Rutgersson, Anna

    2018-01-01

    Global oceans are an important sink of atmospheric carbon dioxide (CO2). Therefore, understanding the air–sea flux of CO2 is a vital part in describing the global carbon balance. Eddy covariance (EC) measurements are often used to study CO2 fluxes from both land and ocean. Values of CO2 are usual...

  13. Morphology of the Ovaries in Condition of Inhalation Intoxication with Dust-Saline Aerosols of the Aral Sea in Female White Rats

    Directory of Open Access Journals (Sweden)

    Yasminur G. Turdybekova

    2018-06-01

    CONCLUSIONS: Taking into account the proven effect of dust-saline aerosols on the production of estrogen, the violation of the postovulatory phase of the ovarian cycle, we trace the mechanism of folliculogenesis disturbance. This confirms the data of our previous studies on primary and secondary infertility in women living in the Aral Sea region and the necessity of creation and development of preventive measures for the inhabitants of the region.

  14. Sulphate and chloride aerosols during Holocene and last glacial periods preserved in the Talos Dome Ice Core, a peripheral region of Antarctica

    Directory of Open Access Journals (Sweden)

    Yoshinori Iizuka

    2013-04-01

    Full Text Available Antarctic ice cores preserve the record of past aerosols, an important proxy of past atmospheric chemistry. Here we present the aerosol compositions of sulphate and chloride particles in the Talos Dome (TD ice core from the Holocene and Last Glacial Period. We find that the main salt types of both periods are NaCl, Na2SO4 and CaSO4, indicating that TD ice contains relatively abundant sea salt (NaCl from marine primary particles. By evaluating the molar ratio of NaCl to Na2SO4, we show that about half of the sea salt does not undergo sulphatisation during late Holocene. Compared to in inland Antarctica, the lower sulphatisation rate at TD is probably due to relatively little contact between sea salt and sulphuric acid. This low contact rate can be related to a reduced time of reaction for marine-sourced aerosol before reaching TD and/or to a reduced post-depositional effect from the higher accumulation rate at TD. Many sulphate and chloride salts are adhered to silicate minerals. The ratio of sulphate-adhered mineral to particle mass and the corresponding ratio of chloride-adhered mineral both increase with increasing dust concentration. Also, the TD ice appears to contain Ca(NO32 or CaCO3 particles, thus differing from aerosol compositions in inland Antarctica, and indicating the proximity of peripheral regions to marine aerosols.

  15. Toward a minimal representation of aerosols in climate models: description and evaluation in the Community Atmosphere Model CAM5

    Directory of Open Access Journals (Sweden)

    X. Liu

    2012-05-01

    Full Text Available A modal aerosol module (MAM has been developed for the Community Atmosphere Model version 5 (CAM5, the atmospheric component of the Community Earth System Model version 1 (CESM1. MAM is capable of simulating the aerosol size distribution and both internal and external mixing between aerosol components, treating numerous complicated aerosol processes and aerosol physical, chemical and optical properties in a physically-based manner. Two MAM versions were developed: a more complete version with seven lognormal modes (MAM7, and a version with three lognormal modes (MAM3 for the purpose of long-term (decades to centuries simulations. In this paper a description and evaluation of the aerosol module and its two representations are provided. Sensitivity of the aerosol lifecycle to simplifications in the representation of aerosol is discussed.

    Simulated sulfate and secondary organic aerosol (SOA mass concentrations are remarkably similar between MAM3 and MAM7. Differences in primary organic matter (POM and black carbon (BC concentrations between MAM3 and MAM7 are also small (mostly within 10%. The mineral dust global burden differs by 10% and sea salt burden by 30–40% between MAM3 and MAM7, mainly due to the different size ranges for dust and sea salt modes and different standard deviations of the log-normal size distribution for sea salt modes between MAM3 and MAM7. The model is able to qualitatively capture the observed geographical and temporal variations of aerosol mass and number concentrations, size distributions, and aerosol optical properties. However, there are noticeable biases; e.g., simulated BC concentrations are significantly lower than measurements in the Arctic. There is a low bias in modeled aerosol optical depth on the global scale, especially in the developing countries. These biases in aerosol simulations clearly indicate the need for improvements of aerosol processes (e.g., emission fluxes of anthropogenic aerosols and

  16. Data assimilation of CALIPSO aerosol observations

    Directory of Open Access Journals (Sweden)

    T. T. Sekiyama

    2010-01-01

    Full Text Available We have developed an advanced data assimilation system for a global aerosol model with a four-dimensional ensemble Kalman filter in which the Level 1B data from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO were successfully assimilated for the first time, to the best of the authors' knowledge. A one-month data assimilation cycle experiment for dust, sulfate, and sea-salt aerosols was performed in May 2007. The results were validated via two independent observations: 1 the ground-based lidar network in East Asia, managed by the National Institute for Environmental Studies of Japan, and 2 weather reports of aeolian dust events in Japan. Detailed four-dimensional structures of aerosol outflows from source regions over oceans and continents for various particle types and sizes were well reproduced. The intensity of dust emission at each grid point was also corrected by this data assimilation system. These results are valuable for the comprehensive analysis of aerosol behavior as well as aerosol forecasting.

  17. Remote sensing of aerosols by synergy of caliop and modis

    OpenAIRE

    Kudo Rei; Nishizawa Tomoaki; Higurashi Akiko; Oikawa Eiji

    2018-01-01

    For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obt...

  18. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

    Science.gov (United States)

    Gantt, B.; Kelly, J. T.; Bash, J. O.

    2015-11-01

    Sea spray aerosols (SSAs) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. Model evaluations of SSA emissions have mainly focused on the global scale, but regional-scale evaluations are also important due to the localized impact of SSAs on atmospheric chemistry near the coast. In this study, SSA emissions in the Community Multiscale Air Quality (CMAQ) model were updated to enhance the fine-mode size distribution, include sea surface temperature (SST) dependency, and reduce surf-enhanced emissions. Predictions from the updated CMAQ model and those of the previous release version, CMAQv5.0.2, were evaluated using several coastal and national observational data sets in the continental US. The updated emissions generally reduced model underestimates of sodium, chloride, and nitrate surface concentrations for coastal sites in the Bay Regional Atmospheric Chemistry Experiment (BRACE) near Tampa, Florida. Including SST dependency to the SSA emission parameterization led to increased sodium concentrations in the southeastern US and decreased concentrations along parts of the Pacific coast and northeastern US. The influence of sodium on the gas-particle partitioning of nitrate resulted in higher nitrate particle concentrations in many coastal urban areas due to increased condensation of nitric acid in the updated simulations, potentially affecting the predicted nitrogen deposition in sensitive ecosystems. Application of the updated SSA emissions to the California Research at the Nexus of Air Quality and Climate Change (CalNex) study period resulted in a modest improvement in the predicted surface concentration of sodium and nitrate at several central and southern California coastal sites. This update of SSA emissions enabled a more realistic simulation of the atmospheric chemistry in coastal environments where marine air mixes with urban pollution.

  19. Salt tolerance of estuarine benthic macroalgae in the Kattegat-Baltic Sea area

    DEFF Research Database (Denmark)

    Larsen, A.; Sand-Jensen, K.

    2006-01-01

    Tolerance of benthic marine macroalgae to low salinities is believed to be a main determinant of their vertical distribution across the marine coastline and their horizontal distribution from oceanic regions into low-saline bays, fjords and estuaries. Salt tolerance should also be important......, Denmark (salinity: 16 psu, tide 10 cm) to maintain photosynthesis after 4 days exposure to declining salinities (16 to 0 psu). Overall, the algal community had a high short-term tolerance to low salinities because 35 of 44 species maintained more than half the photosynthetic capacity at salinities lower...

  20. Geochemical records of salt-water inflows into the deep basins of the Baltic Sea

    DEFF Research Database (Denmark)

    Neumann, T.; Christiansen, C.; Clasen, S.

    1997-01-01

    The estuarine circulation system of the Baltic Sea promotes stable stratification and bottom water anoxia in sedimentary basins of the Baltic proper. Ingressions of saline, oxygen-rich waters from the North Sea replace the oxygen depleted deep water. Timing and extent of the ingressions vary...... on time-scales of years to decades, and are largely determined by wind-strength and storm frequency over the North Atlantic Ocean and Europe. Mn/Fe-ratios in sediments from a dated sediment core of the Gotland Deep (250 m water depth) record variations in redox conditions that can be linked to historical......-pressure areas over the North Atlantic in more recent times. The last three events have also been observed by hydrographic measurements. During the long time stagnation periods, Fe and Mn will be segregated into a particulate phase (iron sulfide) which accumulates at the seafloor and a dissolved phase (Mn2...

  1. Halogenation processes of secondary organic aerosol and implications on halogen release mechanisms

    Directory of Open Access Journals (Sweden)

    J. Ofner

    2012-07-01

    Full Text Available Reactive halogen species (RHS, such as X·, X2 and HOX containing X = chlorine and/or bromine, are released by various sources like photo-activated sea-salt aerosol or from salt pans, and salt lakes. Despite many studies of RHS reactions, the potential of RHS reacting with secondary organic aerosol (SOA and organic aerosol derived from biomass-burning (BBOA has been neglected. Such reactions can constitute sources of gaseous organohalogen compounds or halogenated organic matter in the tropospheric boundary layer and can influence physicochemical properties of atmospheric aerosols.

    Model SOA from α-pinene, catechol, and guaiacol was used to study heterogeneous interactions with RHS. Particles were exposed to molecular chlorine and bromine in an aerosol smog-chamber in the presence of UV/VIS irradiation and to RHS, released from simulated natural halogen sources like salt pans. Subsequently, the aerosol was characterized in detail using a variety of physicochemical and spectroscopic methods. Fundamental features were correlated with heterogeneous halogenation, which results in new functional groups (FTIR spectroscopy, changes UV/VIS absorption, chemical composition (ultrahigh resolution mass spectroscopy (ICR-FT/MS, or aerosol size distribution. However, the halogen release mechanisms were also found to be affected by the presence of organic aerosol. Those interaction processes, changing chemical and physical properties of the aerosol are likely to influence e.g. the ability of the aerosol to act as cloud condensation nuclei, its potential to adsorb other gases with low-volatility, or its contribution to radiative forcing and ultimately the Earth's radiation balance.

  2. Formation of molecular bromine from the reaction of ozone with deliquesced NaBr aerosol: Evidence for interface chemistry

    Czech Academy of Sciences Publication Activity Database

    Hunt, S. W.; Roeselová, Martina; Wang, W.; Wingen, L. M.; Knipping, E. M.; Tobias, D. J.; Dabdub, D.; Finlayson-Pitts, B. J.

    2004-01-01

    Roč. 108, - (2004), s. 11559-11572 ISSN 1089-5639 Grant - others:NSF(US) 0209719; NSF(US) 0431512 Institutional research plan: CEZ:AV0Z4055905 Keywords : ozone * sea-salt aerosol * molecular dynamics simulation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.639, year: 2004

  3. Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

    Directory of Open Access Journals (Sweden)

    V. Pappas

    2013-08-01

    Full Text Available The new global aerosol climatology named HAC (Hamburg Aerosol Climatology is compared against MODIS (Collection 5, 2000–2007 and CALIOP (Level 2-version 3, 2006–2011 retrievals. The comparison of aerosol optical depth (AOD from HAC against MODIS shows larger HAC AOD values over regions with higher aerosol loads and smaller HAC AOD values than MODIS for regions with lower loads. The HAC data are found to be more reliable over land and for low AOD values. The largest differences between HAC and MODIS occur from March to August for the Northern Hemisphere and from September to February for the Southern Hemisphere. In addition, both the spectral variability and vertical distribution of the HAC AOD are examined at selected AERONET (1998–2007 sites, representative of main aerosol types (pollutants, sea salt, biomass and dust. Based on comparisons against spectral AOD values from AERONET, the mean absolute percentage error in HAC AOD data is 25% at ultraviolet wavelengths (400 nm, 6–12% at visible and 18% at near-infrared (1000 nm. For the same AERONET sites, the HAC AOD vertical distribution is compared against CALIOP space lidar data. On a daily average basis, HAD AOD is less by 9% in the lowest 3 km than CALIOP values, especially for sites with biomass burning smoke, desert dust and sea salt spray. Above the boundary layer, the HAC AOD vertical distribution is reliable.

  4. Inorganic markers, carbonaceous components and stable carbon isotope from biomass burning aerosols in northeast China

    Science.gov (United States)

    Cao, F.; Zhang, Y.; Kawamura, K.

    2015-12-01

    To better characterize the sources of fine particulate matter (i.e. PM2.5) in Sanjiang Plain, Northeast China, aerosol chemical composition such total carbon (TC), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and inorganic ions were studied as well as stable carbon isotopic composition (δ13C) of TC. Intensively open biomass burning episodes were identified from late September to early October by satellite fire and aerosol optical depth maps. During the biomass burning episodes, concentrations of PM2.5, OC, EC, and WSOC increased by a factor of 4-12 compared to non-biomass-burning periods. Non-sea-salt potassium is strongly correlated with PM2.5, OC, EC and WSOC, suggesting an important contribution of biomass burning emission. The enrichment in both the non-sea-salt potassium and chlorine is significantly larger than other inorganic species, indicating that biomass burning aerosols in Sanjiang Plain is mostly fresh and less aged. In addition, WSOC to OC ratio is relatively lower compared to that reported in biomass burning aerosols in tropical regions, supporting that biomass burning aerosols in Sanjiang Plain is mostly primary and secondary organic aerosols is not significant. A lower average δ13C value (-26.2‰) is found for the biomass-burning aerosols, suggesting a dominant contribution from combustion of C3 plants in the studied region.

  5. Source indicators of biomass burning associated with inorganic salts and carboxylates in dry season ambient aerosol in Chiang Mai Basin, Thailand

    Science.gov (United States)

    Tsai, Ying I.; Sopajaree, Khajornsak; Chotruksa, Auranee; Wu, Hsin-Ching; Kuo, Su-Ching

    2013-10-01

    PM10 aerosol was collected between February and April 2010 at an urban site (CMU) and an industrial site (TOT) in Chiang Mai, Thailand, and characteristics and provenance of water-soluble inorganic species, carboxylates, anhydrosugars and sugar alcohols were investigated with particular reference to air quality, framed as episodic or non-episodic pollution. Sulfate, a product of secondary photochemical reactions, was the major inorganic salt in PM10, comprising 25.9% and 22.3% of inorganic species at CMU and TOT, respectively. Acetate was the most abundant monocarboxylate, followed by formate. Oxalate was the dominant dicarboxylate. A high acetate/formate mass ratio indicated that primary traffic-related and biomass-burning emissions contributed to Chiang Mai aerosols during episodic and non-episodic pollution. During episodic pollution carboxylate peaks indicated sourcing from photochemical reactions and/or directly from traffic-related and biomass burning processes and concentrations of specific biomarkers of biomass burning including water-soluble potassium, glutarate, oxalate and levoglucosan dramatically increased. Levoglucosan, the dominant anhydrosugar, was highly associated with water-soluble potassium (r = 0.75-0.79) and accounted for 93.4% and 93.7% of anhydrosugars at CMU and TOT, respectively, during episodic pollution. Moreover, levoglucosan during episodic pollution was 14.2-21.8 times non-episodic lows, showing clearly that emissions from biomass burning are the major cause of PM10 episodic pollution in Chiang Mai. Additionally, the average levoglucosan/mannosan mass ratio during episodic pollution was 14.1-14.9, higher than the 5.73-7.69 during non-episodic pollution, indicating that there was more hardwood burning during episodic pollution. Higher concentrations of glycerol and erythritol during episodic pollution further indicate that biomass burning activities released soil biota from forest and farmland soils.

  6. The "Physical feedbacks of Arctic PBL, Sea ice, Cloud and AerosoL (PASCAL)" campaign during the Arctic POLARSTERN expedition PS106 in spring 2017.

    Science.gov (United States)

    Macke, A.

    2017-12-01

    The Polar regions are important components in the global climate system. The widespread surface snow and ice cover strongly impacts the surface energy budget, which is tightly coupled to global atmospheric and oceanic circulations. The coupling of sea ice, clouds and aerosol in the transition zone between Open Ocean and sea ice is the focus of the PASCAL investigations to improve our understanding of the recent dramatic reduction in Arctic sea-ice. A large variety of active/passive remote sensing, in-situ-aerosol observation, and spectral irradiance measurements have been obtained during the German research icebreaker POLARSTERN expedition PS106, and provided detailed information on the atmospheric spatiotemporal structure, aerosol and cloud chemical and microphysical properties as well as the resulting surface radiation budget. Nearly identical measurements at the AWIPEV Base (German - French Research Base) in Ny-Ålesund close to the Open Ocean and collocated airborne activities of the POLAR 5 and POLAR 6 AWI aircraft in the framework of the ACLOUD project have been carried out in parallel. The airborne observations have been supplemented by observations of the boundary layer structure (mean and turbulent quantities) from a tethered balloon reaching up to 1500 m, which was operated at an ice floe station nearby POLARSTERN for two weeks. All observational activities together with intense modelling at various scales are part of the German Collaborative Research Cluster TR 172 "Arctic Amplification" that aims to provide an unprecedented picture of the complex Arctic weather and climate system. The presentation provides an overview of the measurements on-board POLARSTERN and on the ice floe station during PASCAL from May 24 to July 21 2017. We conclude how these and future similar measurements during the one-year ice drift of POLARSTERN in the framework of MOSAiC help to reduce uncertainties in Arctic aerosol-cloud interaction, cloud radiative forcing, and surface

  7. Radiocarbon-insights into temporal variations in the sources and concentrations of carbonaceous aerosols in the Los Angeles and Salt Lake City Metropolitan Areas

    Science.gov (United States)

    Czimczik, Claudia; Mouteva, Gergana; Simon, Fahrni; Guaciara, Santos; James, Randerson

    2014-05-01

    Increased fossil fuel consumption and biomass burning are contributing to significantly larger emissions of black carbon (BC) aerosols to the atmosphere. Together with organic carbon (OC), BC is a major constituent of fine particulate matter in urban air, contributes to haze and has been linked to a broad array of adverse health effects. Black carbon's high light absorption capacity and role in key (in-)direct climate feedbacks also lead to a range of impacts in the Earth system (e.g. warming, accelerated snow melt, changes in cloud formation). Recent work suggests that regulating BC emissions can play an important role in improving regional air quality and reducing future climate warming. However, BC's atmospheric transport pathways, lifetime and magnitudes of emissions by sector and region, particularly emissions from large urban centers, remain poorly constrained by measurements. Contributions of fossil and modern sources to the carbonaceous aerosol pool (corresponding mainly to traffic/industrial and biomass-burning/biogenic sources, respectively) can be quantified unambiguously by measuring the aerosol radiocarbon (14C) content. However, accurate 14C-based source apportionment requires the physical isolation of BC and OC, and minimal sample contamination with extraneous carbon or from OC charring. Compound class-specific 14C analysis of BC remains challenging due to very small sample sizes (5-15 ug C). Therefore, most studies to date have only analyzed the 14C content of the total organic carbonaceous aerosol fraction. Here, we present time-series 14C data of BC and OC from the Los Angeles (LA) metropolitan area in California - one of two megacities in the United States - and from Salt Lake City (SLC), UT. In the LA area, we analyzed 48h-PM10 samples near the LA port throughout 2007 and 2008 (with the exception of summer). We also collected monthly-PM2.5 samples at the University of California - Irvine, with shorter sampling periods during regional wildfire

  8. Aerosol chemistry over a high altitude station at northeastern Himalayas, India.

    Directory of Open Access Journals (Sweden)

    Abhijit Chatterjee

    Full Text Available BACKGROUND: There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. METHODOLOGY/PRINCIPAL FINDINGS: An extensive aerosol sampling program was conducted in Darjeeling (altitude approximately 2200 meter above sea level (masl, latitude 27 degrees 01'N and longitude 88 degrees 15'E, a high altitude station in northeastern Himalayas, during January-December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5+/-20.8 microg m(-3 and 19.6+/-11.1 microg m(-3 respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH(4NO(3 in fine mode aerosol during winter and as NaNO(3 in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO(2 during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO(4(2- in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. CONCLUSIONS/SIGNIFICANCE: The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over

  9. Aerosol chemistry over a high altitude station at northeastern Himalayas, India.

    Science.gov (United States)

    Chatterjee, Abhijit; Adak, Anandamay; Singh, Ajay K; Srivastava, Manoj K; Ghosh, Sanjay K; Tiwari, Suresh; Devara, Panuganti C S; Raha, Sibaji

    2010-06-16

    There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. An extensive aerosol sampling program was conducted in Darjeeling (altitude approximately 2200 meter above sea level (masl), latitude 27 degrees 01'N and longitude 88 degrees 15'E), a high altitude station in northeastern Himalayas, during January-December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5+/-20.8 microg m(-3) and 19.6+/-11.1 microg m(-3) respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH(4)NO(3) in fine mode aerosol during winter and as NaNO(3) in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO(2) during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO(4)(2-) in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over northeastern Himalayas, and should be useful to policy makers in making control

  10. Characterization of intense aerosol episodes in the Mediterranean basin from satellite observations

    Science.gov (United States)

    Gkikas, Antonis; Hatzianastassiou, Nikos; Mihalopoulos, Nikolaos

    2014-05-01

    The properties and distribution of aerosols over the broader Mediterranean region are complex since particles of different nature are either produced within its boundaries or transported from other regions. Thus, coarse dust aerosols are transported primarily from Sahara and secondarily from Middle East, while fine polluted aerosols are either produced locally from anthropogenic activities or they are transported from neighbouring or remote European areas. Also during summer biomass aerosols are transported towards the Mediterranean, originating from massive and extended fires occurring in northern Balkans and Eastern Europe and favoured by the prevailing synoptic conditions. In addition, sea-salt aerosols originate from the Mediterranean Sea or the Atlantic Ocean. Occasionally, aerosols are encountered at very high concentrations (aerosol episodes or events) significantly affecting atmospheric dynamics and climate as well as human health. Given the coexistence of different aerosols as internal and external mixtures characterizing and discriminating between the different types of aerosol episodes is a big challenge. A characterization and classification of intense aerosol episodes in the Mediterranean basin (March 2000 - February 2007) is attempted in the present study. This is achieved by implementing an objective and dynamic algorithm which uses daily aerosol optical properties derived from satellite measurements, namely MODIS-Terra, Earth Probe (EP)-TOMS and OMI-Aura. The aerosol episodes are first classified into strong and extreme ones, according to their intensity, by means of aerosol optical depth at 550nm (AOD550nm). Subsequently, they are discriminated into the following aerosol types: (i) biomass/urban-industrial (BU), (ii) desert dust (DD), (iii) sea-salt like (SS), (iv) mixed (MX) and (v) undetermined (UN). The classification is based on aerosol optical properties accounting for the particles' size (Ångström exponent, Effective radius), the

  11. Understanding the aerosol information content in multi-spectral reflectance measurements using a synergetic retrieval algorithm

    Directory of Open Access Journals (Sweden)

    D. Martynenko

    2010-11-01

    Full Text Available An information content analysis for multi-wavelength SYNergetic AErosol Retrieval algorithm SYNAER was performed to quantify the number of independent pieces of information that can be retrieved. In particular, the capability of SYNAER to discern various aerosol types is assessed. This information content depends on the aerosol optical depth, the surface albedo spectrum and the observation geometry. The theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum and its accuracy is known under cloud-free conditions, reflectance measurements used in SYNAER is able to provide for 2–4° of freedom that can be attributed to retrieval parameters: aerosol optical depth, aerosol type and surface albedo.

    The focus of this work is placed on an information content analysis with emphasis to the aerosol type classification. This analysis is applied to synthetic reflectance measurements for 40 predefined aerosol mixtures of different basic components, given by sea salt, mineral dust, biomass burning and diesel aerosols, water soluble and water insoluble aerosols. The range of aerosol parameters considered through the 40 mixtures covers the natural variability of tropospheric aerosols. After the information content analysis performed in Holzer-Popp et al. (2008 there was a necessity to compare derived degrees of freedom with retrieved aerosol optical depth for different aerosol types, which is the main focus of this paper.

    The principle component analysis was used to determine the correspondence between degrees of freedom for signal in the retrieval and derived aerosol types. The main results of the analysis indicate correspondence between the major groups of the aerosol types, which are: water soluble aerosol, soot, mineral dust and sea salt and degrees of freedom in the algorithm and show the ability of the SYNAER to

  12. Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador – Pacific or Atlantic origin?

    Directory of Open Access Journals (Sweden)

    S. Makowski Giannoni

    2016-08-01

    Full Text Available Sea salt (NaCl has recently been proven to be of the utmost importance for ecosystem functioning in Amazon lowland forests because of its impact on herbivory, litter decomposition and, thus, carbon cycling. Sea salt deposition should generally decline as distance from its marine source increases. For the Amazon, a negative east–west gradient of sea salt availability is assumed as a consequence of the barrier effect of the Andes Mountains for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rainforest in the Andes of southern Ecuador. To analyse sea salt availability, we investigated the deposition of sodium (Na+ and chloride (Cl−, which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, sea salt deposition was analysed from both, rain and occult precipitation (OP along an altitudinal gradient over a period between 2004 and 2009. To assess the influence of easterly and westerly air masses on the deposition of sodium and chloride over southern Ecuador, sea salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC reanalysis data set and back-trajectory statistical methods were combined. Our results, based on deposition time series, show a clear difference in the temporal variation of sodium and chloride concentration and Na+ ∕ Cl− ratio in relation to height and exposure to winds. At higher elevations, sodium and chloride present a higher seasonality and the Na+ ∕ Cl− ratio is closer to that of sea salt. Medium- to long-range sea salt transport exhibited a similar seasonality, which shows the link between our measurements at high elevations and the sea salt synoptic transport. Although the influence of the easterlies was predominant regarding the atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the

  13. Non-polar organic compounds in marine aerosols over the northern South China Sea: Influence of continental outflow.

    Science.gov (United States)

    Zhao, Yan; Zhang, Yingyi; Fu, Pingqing; Ho, Steven Sai Hang; Ho, Kin Fai; Liu, Fobang; Zou, Shichun; Wang, Shan; Lai, Senchao

    2016-06-01

    Filter samples of total suspended particle (TSP) collected during a cruise campaign over the northern South China Sea (SCS) from September to October 2013 were analyzed for non-polar organic compounds (NPOCs) as well as organic carbon (OC), elemental carbon (EC) and water-soluble ions. A total of 115 NPOCs species in groups of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), iso-/antiso-alkanes, hopanes, steranes, methylalkanes, branched alkanes, cycloalkanes, alkenes and phthalates were detected. The characteristics of NPOCs in marine TSP samples were investigated to understand the sources from the Asian continent and other regions. The concentrations of total NPOCs ranged from 19.8 to 288.2 ng/m(3) with an average of 87.9 ng/m(3), which accounted for 0.8-1.7% (average 1.0%) of organic matter (OM). n-Alkanes was the predominant group, accounting for 43.1-79.5%, followed by PAHs (5.5-44.4%) and hopanes (1.6-11.4%). We found that primary combustion (biomass burning/fossil fuel combustion) was the dominant source for the majority of NPOCs (89.1%). Biomass burning in southern/southeastern China via long-range transport was proposed to be a major contributor of NPOCs in marine aerosols over the northern SCS, suggested by the significant correlations between nss-K(+) and NPOCs groups as well as the analysis of air mass back-trajectory and fire spots. For the samples with strong continental influence, the strong enhancement in concentrations of n-alkanes, PAHs, hopanes and steranes were attributed to fossil fuel (coal/petroleum) combustion. In addition, terrestrial plants waxes were another contributor to NPOCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

    Science.gov (United States)

    Schwier, A. N.; Rose, C.; Asmi, E.; Ebling, A. M.; Landing, W. M.; Marro, S.; Pedrotti, M.-L.; Sallon, A.; Iuculano, F.; Agusti, S.; Tsiola, A.; Pitta, P.; Louis, J.; Guieu, C.; Gazeau, F.; Sellegri, K.

    2015-07-01

    The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of CO2 to simulate the conditions foreseen in this region for the coming decades. After seawater sampling, primary bubble-bursting aerosol experiments were performed using a plunging water jet system to test both chemical and physical aerosol parameters (10-400 nm). Comparing results obtained during pre-bloom and oligotrophic conditions, we find the same four log-normal modal diameters (18.5 ± 0.6, 37.5 ± 1.4, 91.5 ± 2.0, 260 ± 3.2 nm) describing the aerosol size distribution during both campaigns, yet pre-bloom conditions significantly increased the number fraction of the second (Aitken) mode, with an amplitude correlated to virus-like particles, heterotrophic prokaryotes, TEPs (transparent exopolymeric particles), chlorophyll a and other pigments. Organic fractions determined from kappa closure calculations for the diameter, Dp ~ 50 nm, were much larger during the pre-bloom period (64 %) than during the oligotrophic period (38 %), and the organic fraction decreased as the particle size increased. Combining data from both campaigns together, strong positive correlations were found between the organic fraction of the aerosol and chlorophyll a concentrations, heterotrophic and autotrophic bacteria abundance, and dissolved organic carbon (DOC) concentrations. As a consequence of the changes in the organic fraction and the size distributions between pre-bloom and oligotrophic periods, we find that the ratio of cloud condensation nuclei (CCN) to condensation nuclei (CN) slightly decreased during the

  15. Biogeographical diversity of leaf-associated microbial communities from salt-secreting Tamarix trees of the Dead Sea region.

    Science.gov (United States)

    Qvit-Raz, Noga; Finkel, Omri M; Al-Deeb, Taghleb M; Malkawi, Hanan I; Hindiyeh, Muna Y; Jurkevitch, Edouard; Belkin, Shimshon

    2012-02-01

    The leaves of Tamarix, a salt-secreting desert tree, form an extreme niche that harbors a unique microbial community. In view of the global distribution of this tree, its island-like phyllosphere is highly suitable for studying microbial diversity along geographical gradients. Here we present an analysis of microbial community diversity using leaf surface samples collected at six different sites, on both sides of the Dead Sea, over a period of one year. Biodiversity analysis of denaturing gradient gel electrophoresis (DGGE) patterns of the bacterial 16S rRNA gene revealed a significant degree of bacterial community similarity within trees sampled at the same site, much higher than the similarity between trees from different geographical locations. Statistical analysis indicated that the degree of similarity was negatively correlated with the distance between sampling sites, and that a weak correlation existed between diversity and leaf pH. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  16. Combined Observational and Modeling Efforts to Better Understand Aerosol-Cloud-Precipitation Interactions Over Land: Preliminary Results from 7-SEAS/BASELInE 2013

    Science.gov (United States)

    Loftus, Adrian M.; Tsay, Si-Chee

    2015-01-01

    This talk presents some of the detailed observations of low-level stratocumulus over northern Vietnam during 7-SEASBASELInE 2013 by SMARTLabs' ACHIEVE W-band cloud radar and other remote sensing instruments. These observations are the first of their kind for this region and will aid in ongoing studies of biomass-burning aerosol impacts on local and regional weather and climate. Preliminary results from simulations using the Goddard Cumulus Ensemble (GCE) with recently implemented triple-moment bulk microphysics to examine the sensitivity of low-level stratocumulus over land to aerosols are also presented. Recommendations for future observational activities in the 7-SEAS northern region in collaboration with international partners will also be discussed.

  17. Increases in wintertime PM2.5 sodium and chloride linked to snowfall and road salt application

    Science.gov (United States)

    Kolesar, Katheryn R.; Mattson, Claire N.; Peterson, Peter K.; May, Nathaniel W.; Prendergast, Rashad K.; Pratt, Kerri A.

    2018-03-01

    The application of salts and salty brines to roads is common practice during the winter in many urban environments. Road salts can become aerosolized, thereby injecting sodium and chloride particulate matter (PM) into the atmosphere. Here, data from the United States Environmental Protection Agency Chemical Speciation Monitoring Network were used to assess temporal trends of sodium and chloride PM2.5 (PM road salt aerosols. Sodium and chloride PM2.5 concentrations were an average of three times higher in the winter, as compared to the summer, for locations with greater than 25 cm of average annual snowfall. Winter urban chloride PM2.5 concentrations attributed to road salt can even sometimes rival those of coastal sea spray aerosol-influenced sites. In most snow-influenced cities, chloride and sodium PM2.5 concentrations were positively correlated with snowfall; however, this relationship is complicated by differences in state and local winter maintenance practices. This study highlights the ubiquity of road salt aerosols in the United States and their potential impact on wintertime urban air quality, particularly due to the potential for multiphase reactions to liberate chlorine from the particle-phase. Since road salt application is a common practice in wintertime urban environments across the world, it is imperative that road salt application emissions, currently not included in inventories, and its impacts be investigated through measurements and modeling.

  18. Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine

    Science.gov (United States)

    Nielsen, Martha G.; Dudley, Robert W.

    2013-01-01

    Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median

  19. Linking remotely sensed aerosol types to their chemical composition

    Science.gov (United States)

    Dawson, K. W.; Kacenelenbogen, M. S.; Johnson, M. S.; Burton, S. P.; Hostetler, C. A.; Meskhidze, N.

    2016-12-01

    Aerosol types measured during the Ship-Aircraft Bio-Optical Research (SABOR) experiment are related to GEOS-Chem model chemical composition. The application for this procedure to link model chemical components to aerosol type is desirable for understanding aerosol evolution over time. The Mahalanobis distance (DM) statistic is used to cluster model groupings of five chemical components (organic carbon, black carbon, sea salt, dust and sulfate) in a way analogous to the methods used by Burton et al. [2012] and Russell et al. [2014]. First, model-to-measurement evaluation is performed by collocating vertically resolved aerosol extinction from SABOR High Spectral Resolution LiDAR (HSRL) to the GEOS-Chem nested high-resolution data. Comparisons of modeled-to-measured aerosol extinction are shown to be within 35% ± 14%. Second, the model chemical components are calculation into five variables to calculate the DM and cluster means and covariances for each HSRL-retrieved aerosol type. The layer variables from the model are aerosol optical depth (AOD) ratios of (i) sea salt and (ii) dust to total AOD, mass ratios of (iii) total carbon (i.e. sum of organic and black carbon) to the sum of total carbon and sulfate (iv) organic carbon to black carbon, and (v) the natural log of the aerosol-to-molecular extinction ratio. Third, the layer variables and at most five out of twenty SABOR flights are used to form the pre-specified clusters for calculating DM and to assign an aerosol type. After determining the pre-specified clusters, model aerosol types are produced for the entire vertically resolved GEOS-Chem nested domain over the United States and the model chemical component distributions relating to each type are recorded. Resulting aerosol types are Dust/Dusty Mix, Maritime, Smoke, Urban and Fresh Smoke (separated into `dark' and `light' by a threshold of the organic to black carbon ratio). Model-calculated DM not belonging to a specific type (i.e. not meeting a threshold

  20. Efficacy of a Rinse Containing Sea Salt and Lysozyme on Biofilm and Gingival Health in a Group of Young Adults: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Jeyaraj Hoover

    2017-01-01

    Full Text Available Objectives. To evaluate new mouth rinse containing sea salt, xylitol, and lysozyme on biofilm formation and gingival health in a group of young adults. Methods. The subjects were divided into two groups of 15 subjects each: control (A and experimental group (B. The Turesky modification of Quigley-Hein plaque index was used to evaluate plaque scores while the presence or absence of gingival bleeding was used to determine gingival health. Measurements were done at baseline and at the end of the one-month trial period by one blinded examiner on six representative teeth. Group (A maintained standardized oral health practices for the duration of the experiment. In addition, group (B rinsed with a tablespoon of the provided sea salt mouth rinse for 30 seconds once in the morning and at night. After the 30-day trial period, subjects in both groups were reassessed as per baseline. Results. There were no statistically significant differences in the overall reduction from baseline in the mean plaque and gingivitis scores on all surfaces or on individual surfaces. Conclusion. Within the limitations of the study, rinsing with sea salt for thirty days did not affect the gingival and plaque scores in a group of young adults.

  1. Sellafield waste radionuclides in Irish sea intertidal and salt marsh sediments.

    Science.gov (United States)

    Mackenzie, A B; Scott, R D

    1993-09-01

    Low level liquid radioactive waste discharges from the Sellafield nuclear fuel reprocessing plant in north west England had generated environmental inventories of about 3 × 10(16) Bq of(137)Cs, 6.8 × 10(14) Bq of(239,240)Pu and 8.9 × 10(14) Bq of(241)Am by 1990. Most of the(239,240)Pu and(241)Am and about 10% of the(137)Cs has been retained in a deposit of fine marine sediment close to the discharge point. The quantities of radionuclides discharged annually from Sellafield decreased by two orders of magnitude from the mid-1970s to 1990 but estimated critical group internal and external exposure decreased by less than one order of magnitude over this period. This indicates that during the period of reduced discharges, radionuclides already in the environment from previous releases continued to contribute to the critical group exposure and highlights the need to understand processes controlling the environmental distribution of the radionuclides.Redistribution of the contaminated marine sediment is potentially of major significance in this context, in particular if it results in transport of radionuclides to intertidal areas, where contact with the human population is relatively likely.A review is presented of published work relating to Sellafield waste radionuclides in Irish Sea sediments. Data on temporal and spatial trends in radionuclide concentrations and activity ratios are collated from a number of sources to show that the dominant mechanism of radionuclide supply to intertidal areas is by redistribution of the contaminated marine sediment. The implications of this mechanism of supply for trends in critical group radiation exposure are considered.

  2. Assessment of Aerosol Distributions from GEOS-5 Using the CALIPSO Feature Mask

    Science.gov (United States)

    Welton, Ellsworth

    2010-01-01

    A-train sensors such as MODIS, MISR, and CALIPSO are used to determine aerosol properties, and in the process a means of estimating aerosol type (e.g. smoke vs. dust). Correct classification of aerosol type is important for climate assessment, air quality applications, and for comparisons and analysis with aerosol transport models. The Aerosols-Clouds-Ecosystems (ACE) satellite mission proposed in the NRC Decadal Survey describes a next generation aerosol and cloud suite similar to the current A-train, including a lidar. The future ACE lidar must be able to determine aerosol type effectively in conjunction with modeling activities to achieve ACE objectives. Here we examine the current capabilities of CALIPSO and the NASA Goddard Earth Observing System general circulation model and data assimilation system (GEOS-5), to place future ACE needs in context. The CALIPSO level 2 feature mask includes vertical profiles of aerosol layers classified by type. GEOS-5 provides global 3D aerosol mass for sulfate, sea salt, dust, and black and organic carbon. A GEOS aerosol scene classification algorithm has been developed to provide estimates of aerosol mixtures and extinction profiles along the CALIPSO orbit track. In previous work, initial comparisons between GEOS-5 derived aerosol mixtures and CALIPSO derived aerosol types were presented for July 2007. In general, the results showed that model and lidar derived aerosol types did not agree well in the boundary layer. Agreement was poor over Europe, where CALIPSO indicated the presence of dust and pollution mixtures yet GEOS-5 was dominated by pollution with little dust. Over the ocean in the tropics, the model appeared to contain less sea salt than detected by CALIPSO, yet at high latitudes the situation was reserved. Agreement between CALIPSO and GEOS-5, aerosol types improved above the boundary layer, primarily in dust and smoke dominated regions. At higher altitudes (> 5 km), the model contained aerosol layers not detected

  3. Properties of aerosols and formation mechanisms over southern China during the monsoon season

    Directory of Open Access Journals (Sweden)

    W. Chen

    2016-10-01

    Full Text Available Measurements of size-resolved aerosols from 0.25 to 18 µm were conducted at three sites (urban, suburban and background sites and used in tandem with an atmospheric transport model to study the size distribution and formation of atmospheric aerosols in southern China during the monsoon season (May–June in 2010. The mass distribution showed the majority of chemical components were found in the smaller size bins (< 2.5 µm. Sulfate was found to be strongly correlated with aerosol water and anticorrelated with atmospheric SO2, hinting at aqueous-phase reactions being the main formation pathway. Nitrate was the only major species that showed a bimodal distribution at the urban site and was dominated by the coarse mode in the other two sites, suggesting that an important component of nitrate formation is chloride depletion of sea salt transported from the South China Sea. In addition to these aqueous-phase reactions and interactions with sea salt aerosols, new particle formation, chemical aging, and long-range transport from upwind urban or biomass burning regions was also found to be important in at least some of the sites on some of the days. This work therefore summarizes the different mechanisms that significantly impact the aerosol chemical composition during the monsoon over southern China.

  4. Evaporating brine from frost flowers with electron microscopy and implications for atmospheric chemistry and sea-salt aerosol formation

    Czech Academy of Sciences Publication Activity Database

    Yang, X.; Neděla, Vilém; Runštuk, Jiří; Ondrušková, G.; Krausko, J.; Vetráková, L'.; Heger, D.

    2017-01-01

    Roč. 17, č. 10 (2017), s. 6291-6303 ISSN 1680-7316 R&D Projects: GA ČR(CZ) GA14-22777S Institutional support: RVO:68081731 Keywords : experimental-computational approach * aqueous-solutions * boundary-layer * blowing snow * spectroscopic properties * low-temperatures Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Meteorology and atmospheric sciences Impact factor: 5.318, year: 2016

  5. Enzymatic methods for the determination of pollution in seawater using salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius

    International Nuclear Information System (INIS)

    Menzorova, Natalie I.; Seitkalieva, Alexandra V.; Rasskazov, Valery A.

    2014-01-01

    Highlights: • Alkaline phosphatase from eggs of the sea urchin (StAP) proved to be active in seawater. • Activity of StAP is inhibited by very low concentrations of heavy metal. • A test to assess sea and fresh water quality has been developed basing on StAP. • For the first time a salt resistant alkaline phosphatase has been found in eukaryote. - Abstract: A new salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius (StAP) has been shown to have a unique property to hydrolyze substrate in seawater without loss of enzymatic activity. The enzyme has pH optimum at 8.0–8.5. Model experiments showed various concentrations of copper, zinc, cadmium and lead added to seawater or a standard buffer mixture to inhibit completely the enzyme activity at the concentrations of 15–150 μg/l. StAP sensitivity to the presence in seawater of metals, pesticides, detergents and oil products appears to be considerably less. Samples of seawater taken from aquatic areas of the Troitsy Bay of the Peter the Great Bay, Japan Sea have been shown to inhibit the enzyme activity; the same was shown for the samples of fresh waters. The phosphatase inhibition assay developed proved to be highly sensitive, technically easy-to use allowing to test a great number of samples

  6. From BASE-ASIA Toward 7-SEAS: A Satellite-Surface Perspective of Boreal Spring Biomass-Burning Aerosols and Clouds in Southeast Asia

    Science.gov (United States)

    Tsay, Si-Chee; Hsu, N. Christina; Lau, William K.-M.; Li, Can; Gabriel, Philip M.; Ji, Qiang; Holben, Brent N.; Welton, E. Judd; Nguyen, Anh X.; Janjai, Serm; hide

    2013-01-01

    In this paper, we present recent field studies conducted by NASA's SMART-COMMIT (and ACHIEVE, to be operated in 2013) mobile laboratories, jointly with distributed ground-based networks (e.g., AERONET, http://aeronet.gsfc.nasa.gov/ and MPLNET, http://mplnet.gsfc.nasa.gov/) and other contributing instruments over northern Southeast Asia. These three mobile laboratories, collectively called SMARTLabs (cf. http://smartlabs.gsfc.nasa.gov/, Surface-based Mobile Atmospheric Research & Testbed Laboratories) comprise a suite of surface remote sensing and in-situ instruments that are pivotal in providing high spectral and temporal measurements, complementing the collocated spatial observations from various Earth Observing System (EOS) satellites. A satellite-surface perspective and scientific findings, drawn from the BASE-ASIA (2006) field deployment as well as a series of ongoing 7-SEAS (2010-13) field activities over northern Southeast Asia are summarized, concerning (i) regional properties of aerosols from satellite and in situ measurements, (ii) cloud properties from remote sensing and surface observations, (iii) vertical distribution of aerosols and clouds, and (iv) regional aerosol radiative effects and impact assessment. The aerosol burden over Southeast Asia in boreal spring, attributed to biomass burning, exhibits highly consistent spatial and temporal distribution patterns, with major variability arising from changes in the magnitude of the aerosol loading mediated by processes ranging from large-scale climate factors to diurnal meteorological events. Downwind from the source regions, the tightly coupled-aerosolecloud system provides a unique, natural laboratory for further exploring the micro- and macro-scale relationships of the complex interactions. The climatic significance is presented through large-scale anti-correlations between aerosol and precipitation anomalies, showing spatial and seasonal variability, but their precise cause-and-effect relationships

  7. Aerosol composition and properties variation at the ground and over the column under different air masses advection in South Italy.

    Science.gov (United States)

    Pavese, G; Lettino, A; Calvello, M; Esposito, F; Fiore, S

    2016-04-01

    Aerosol composition and properties variation under the advection of different air masses were investigated, as case studies, by contemporary measurements over the atmospheric column and at the ground in a semi-rural site in South Italy. The absence of local strong sources in this area allowed to characterize background aerosol and to compare particle mixing effects under various atmospheric circulation conditions. Aerosol optical depth (AOD) and Ǻngström parameters from radiometric measurements allowed the detection and identification of polluted, dust, and volcanic atmospheric conditions. AODs were the input for a suitable model to evaluate the columnar aerosol composition, according to six main atmospheric components (water-soluble, soot, sea salt accumulation, sea salt coarse, mineral dus,t and biological). Scanning electron microscope (SEM) analysis of particulate sampled with a 13-stage impactor at the ground showed not only fingerprints typical of the different air masses but also the effects of transport and aging on atmospheric particles, suggesting processes that changed their chemical and optical properties. Background columnar aerosol was characterized by 72% of water-soluble and soot, in agreement with ground-based findings that highlighted 60% of contribution from anthropogenic carbonate particles and soot. In general, a good agreement between ground-based and columnar results was observed. Under the advection of trans-boundary air masses, water-soluble and soot were always present in columnar aerosol, whereas, in variable percentages, sea salt and mineral particles characterized both dust and volcanic conditions. At the ground, sulfates characterized the amorphous matrix produced in finer stages by the evaporation of solutions of organic and inorganic aerosols. Sulfates were also one of the key players involved in heterogeneous chemical reactions, producing complex secondary aerosol, as such clay-sulfate internally mixed particle externally mixed

  8. Salirhabdus euzebyi gen. nov., sp. nov., a Gram-positive, halotolerant bacterium isolated from a sea salt evaporation pond.

    Science.gov (United States)

    Albuquerque, Luciana; Tiago, Igor; Rainey, Fred A; Taborda, Marco; Nobre, M Fernanda; Veríssimo, António; da Costa, Milton S

    2007-07-01

    A low-G+C, Gram-positive bacterium, designated CVS-14(T), was recovered from a sea salt evaporation pond on the island of Sal in the Cape Verde Archipelago. This organism was catalase- and oxidase-positive. Cells were motile, spore-forming aerobic rods, with an optimum growth temperature of about 35-40 degrees C and optimum pH between 7.0 and 8.5. Optimal growth occurred in media containing 4-6 % (w/v) NaCl, although the organism was able to grow in medium without added NaCl and in medium containing 16 % NaCl. The cell-wall peptidoglycan was of A1 gamma type and the major respiratory quinone was menaquinone 7 (MK-7). Major fatty acids were iso-15 : 0, anteiso-15 : 0, iso-17 : 0 and anteiso-17 : 0. The DNA G+C content was 37.0 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain CVS-14(T) formed a distinct new branch within the radiation of the moderately halophilic bacilli group, forming a separate lineage from species of the genera Salinibacillus, Paucisalibacillus, Oceanobacillus, Lentibacillus and Virgibacillus. Strain CVS-14(T) showed 16S rRNA gene pairwise similarity values of approximately 95 % with species of the genus Salinibacillus. On the basis of morphological, physiological, chemotaxonomic and phylogenetic characteristics, strain CVS-14(T) is considered to represent a novel species in a new genus, for which the name Salirhabdus euzebyi gen. nov., sp. nov. is proposed. The type strain is CVS-14(T) (=LMG 22839(T)=CIP 108577(T)).

  9. Biomass burning and its effects on fine aerosol acidity, water content and nitrogen partitioning

    Science.gov (United States)

    Bougiatioti, Aikaterini; Nenes, Athanasios; Paraskevopoulou, Despina; Fourtziou, Luciana; Stavroulas, Iasonas; Liakakou, Eleni; Myriokefalitakis, Stelios; Daskalakis, Nikos; Weber, Rodney; Kanakidou, Maria; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos

    2017-04-01

    Aerosol acidity is an important property that drives the partitioning of semi-volatile species, the formation of secondary particulate matter and metal and nutrient solubility. Aerosol acidity varies considerably between aerosol types, RH, temperature, the degree of atmospheric chemical aging and may also change during transport. Among aerosol different sources, sea salt and dust have been well studied and their impact on aerosol acidity and water uptake is more or less understood. Biomass burning (BB) on the other hand, despite its significance as a source in a regional and global scale, is much less understood. Currently, there is no practical and accurate enough method, to directly measure the pH of in-situ aerosol. The combination of thermodynamic models, with targeted experimental observations can provide reliable predictions of aerosol particle water and pH, using as input the concentration of gas/aerosol species, temperature (T), and relative humidity (RH). As such an example, ISORROPIA-II (Fountoukis and Nenes, 2007) has been used for the thermodynamic analysis of measurements conducted in downtown Athens during winter 2013, in order to evaluate the effect of BB on aerosol water and acidity. Biomass burning, especially during night time, was found to contribute significantly to the increased organics concentrations, but as well to the BC component associated with wood burning, particulate nitrates, chloride, and potassium. These increased concentrations were found to impact on fine aerosol water, with Winorg having an average concentration of 11±14 μg m-3 and Worg 12±19 μg m-3 with the organic component constituting almost 38% of the total calculated submicron water. When investigating the fine aerosol acidity it was derived that aerosol was generally acidic, with average pH during strong BB influence of 2.8±0.5, value similar to the pH observed for regional aerosol influenced by important biomass burning episodes at the remote background site of

  10. Examination of aerosol distributions and radiative effects over the Bay of Bengal and the Arabian Sea region during ICARB using satellite data and a general circulation model

    Directory of Open Access Journals (Sweden)

    R. Cherian

    2012-02-01

    Full Text Available In this paper we analyse aerosol loading and its direct radiative effects over the Bay of Bengal (BoB and Arabian Sea (AS regions for the Integrated Campaign on Aerosols, gases and Radiation Budget (ICARB undertaken during 2006, using satellite data from the MODerate Resolution Imaging Spectroradiometer (MODIS on board the Terra and Aqua satellites, the Aerosol Index from the Ozone Monitoring Instrument (OMI on board the Aura satellite, and the European-Community Hamburg (ECHAM5.5 general circulation model extended by Hamburg Aerosol Module (HAM. By statistically comparing with large-scale satellite data sets, we firstly show that the aerosol properties measured during the ship-based ICARB campaign and simulated by the model are representative for the BoB and AS regions and the pre-monsoon season. In a second step, the modelled aerosol distributions were evaluated by a comparison with the measurements from the ship-based sunphotometer, and the satellite retrievals during ICARB. It is found that the model broadly reproduces the observed spatial and temporal variability in aerosol optical depth (AOD over BoB and AS regions. However, AOD was systematically underestimated during high-pollution episodes, especially in the BoB leg. We show that this underprediction of AOD is mostly because of the deficiencies in the coarse mode, where the model shows that dust is the dominant component. The analysis of dust AOD along with the OMI Aerosol Index indicate that missing dust transport that results from too low dust emission fluxes over the Thar Desert region in the model caused this deficiency. Thirdly, we analysed the spatio-temporal variability of AOD comparing the ship-based observations to the large-scale satellite observations and simulations. It was found that most of the variability along the track was from geographical patterns, with a minor influence by single events. Aerosol fields were homogeneous enough to yield a good statistical agreement

  11. Ammonia and ammonium over the southern Baltic Sea. Part 1. Preparation of aerosol and air samples for the determination of ammonia by the indophenol method

    Directory of Open Access Journals (Sweden)

    Lucyna Falkowska

    2004-06-01

    Full Text Available 1997 saw the start of a study into the spatial and temporal changes in the chemical composition of the atmosphere over the littoral and offshore waters of the Baltic Sea. Collection of samples and their subsequent chemical analysis was preceded by meticulous laboratory experiments concerning the validation and adaptation of the analytical procedures. The colorimetric indophenol blue technique was used to analyse the aerosol samples for the concentration of ammonium ions and the air samples for their gaseous ammonia. The samples were collected with PTFE-filters and Whatman 41 filters coated with 5% orthophosphoric acid. This acid enhances the aerosol sampling efficacy but reduces the pH of the reaction in which indophenol is formed. The pH of the aerosol samples thus had to be raised, and this in turn required an alteration to the original procedure prior to ammonia determination. It was demonstrated that the addition of 0.1 N KOH to the filters coated with H3PO4 increases the pH of the reaction medium to the required level of pH = 8-11.5 and does not substantially influence the precision of the determination; the error of the modified procedure was of the order of 5.2%.      Air samples for the determination of gaseous ammonia were collected with annular denuders. Oxalic acid and citric acid are the usual impregnating agents. In the present experiments oxalic acid was used for denuder impregnation; it turned out to be more effective than citric acid under the conditions of the southern Baltic Sea.      The detection limit of the indophenol blue method in these laboratory experiments was 0.045 mmol dm-3. The respective relative standard deviations (RSD within the range of higher and lower concentrations were 0.64% and 4.53%.

  12. A Subject of Sea and Salty Sediment: Diasporic Labor and Queer (Belonging in Monique Truong’s The Book of Salt

    Directory of Open Access Journals (Sweden)

    Michelle Peek

    2012-06-01

    Full Text Available Caught having an affair while employed at the home of the governor-general of Saigon, Vietnamese cook, migrant worker, and narrator of Monique Truong’s The Book of Salt, Binh, is cast out of his natal home, and sets off for the open sea, winding up as a live-in cook in the household of lesbian couple Gertrude Stein and Alice B. Toklas. As an abstract source of labor and culinary pleasure to those he encounters in Paris, Binh concludes, despondently, that he is, “nothing but a series of destinations with no meaningful expanses in between.” Yet the “expanses in between,” most notably in reference to waterways, allude to a central trope of Vietnamese culture. Incorporating Vietnamese symbolism with formative migratory experiences, this essay argues that Truong constructs a subject who can be read through both affective forms of national belonging as well as a broader queer diasporic community. It also explores Binh’s percipient tongue as one that is ever critical of the dynamics of power and privilege, and ever sensitive to the variances in salt (of sea, sweat, tears. The Book of Salt thus mediates the possibility of a gustatory epistemology and community constituted in the sensate, attuned to divergent experiences of mobility, labor, and love.

  13. Simple simultaneous determination of soluble and insoluble trace metal components in sea salts by a combined coprecipitation/X-ray fluorescence method

    International Nuclear Information System (INIS)

    Iwatsuki, Masaaki; Ali, Muhammad; Kyotani, Tomohiro; Fukasawa, Tsutomu

    1996-01-01

    An X-ray fluorescence method using the coprecipitation-preconcentration technique has been developed for simple determination of both acid-soluble and insoluble trace metal components, such as manganese, iron, nickel, copper and zinc in sea salts. A salt sample is dissolved in a nitric acid solution, and the residue is filtered off onto a membrane filter. After the pH is adjusted to 7-8, the filtrate is boiled, followed by addition of aluminum carrier, oxine and thionalide solutions. The solution is re-adjusted to pH 9, and kept at 80-85degC for 60 min. The precipitates are filtered off onto another membrane filter. X-Ray fluorescence intensities from two filters loaded with the residue and precipitates are measured and the concentrations of the elements are determined simultaneously using the calibration curves. Detection limits were 0.01 μg g -1 for manganese and copper, 0.04 μg g -1 for nickel and zinc, and 0.05 μg g -1 for iron, regardless of the soluble and the insoluble components. The present method was successfully applied to the analysis of sea salt samples. (author)

  14. Toward a Minimal Representation of Aerosols in Climate Models: Description and Evaluation in the Community Atmosphere Model CAM5

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaohong; Easter, Richard C.; Ghan, Steven J.; Zaveri, Rahul A.; Rasch, Philip J.; Shi, Xiangjun; Lamarque, J.-F.; Gettelman, A.; Morrison, H.; Vitt, Francis; Conley, Andrew; Park, S.; Neale, Richard; Hannay, Cecile; Ekman, A. M.; Hess, Peter; Mahowald, N.; Collins, William D.; Iacono, Michael J.; Bretherton, Christopher S.; Flanner, M. G.; Mitchell, David

    2012-05-21

    A modal aerosol module (MAM) has been developed for the Community Atmosphere Model version 5 (CAM5), the atmospheric component of the Community Earth System Model version 1 (CESM1). MAM is capable of simulating the aerosol size distribution and both internal and external mixing between aerosol components, treating numerous complicated aerosol processes and aerosol physical, chemical and optical properties in a physically based manner. Two MAM versions were developed: a more complete version with seven-lognormal modes (MAM7), and a three-lognormal mode version (MAM3) for the purpose of long-term (decades to centuries) simulations. Major approximations in MAM3 include assuming immediate mixing of primary organic matter (POM) and black carbon (BC) with other aerosol components, merging of the MAM7 fine dust and fine sea salt modes into the accumulation mode, merging of the MAM7 coarse dust and coarse sea salt modes into the single coarse mode, and neglecting the explicit treatment of ammonia and ammonium cycles. Simulated sulfate and secondary organic aerosol (SOA) mass concentrations are remarkably similar between MAM3 and MAM7 as most ({approx}90%) of these aerosol species are in the accumulation mode. Differences of POM and BC concentrations between MAM3 and MAM7 are also small (mostly within 10%) because of the assumed hygroscopic nature of POM, so that freshly emitted POM and BC are wet-removed before mixing internally with soluble aerosol species. Sensitivity tests with the POM assumed to be hydrophobic and with slower aging process increase the POM and BC concentrations, especially at high latitudes (by several times). The mineral dust global burden differs by 10% and sea salt burden by 30-40% between MAM3 and MAM7 mainly due to the different size ranges for dust and sea salt modes and different standard deviations of log-normal size distribution for sea salt modes between MAM3 and MAM7. The model is able to qualitatively capture the observed geographical and

  15. Aerosol observation using multi-wavelength Mie-Raman lidars of the Ad-Net and aerosol component analysis

    Science.gov (United States)

    Nishizawa, Tomoaki; Sugimoto, Nobuo; Shimizu, Atsushi; Uno, Itsushi; Hara, Yukari; Kudo, Rei

    2018-04-01

    We deployed multi-wavelength Mie-Raman lidars (MMRL) at three sites of the AD-Net and have conducted continuous measurements using them since 2013. To analyze the MMRL data and better understand the externally mixing state of main aerosol components (e.g., dust, sea-salt, and black carbon) in the atmosphere, we developed an integrated package of aerosol component retrieval algorithms, which have already been developed or are being developed, to estimate vertical profiles of the aerosol components. This package applies to the other ground-based lidar network data (e.g., EARLINET) and satellite-borne lidar data (e.g., CALIOP/CALIPSO and ATLID/EarthCARE) as well as the other lidar data of the AD-Net.

  16. Aerosol observation using multi-wavelength Mie-Raman lidars of the Ad-Net and aerosol component analysis

    Directory of Open Access Journals (Sweden)

    Nishizawa Tomoaki

    2018-01-01

    Full Text Available We deployed multi-wavelength Mie-Raman lidars (MMRL at three sites of the AD-Net and have conducted continuous measurements using them since 2013. To analyze the MMRL data and better understand the externally mixing state of main aerosol components (e.g., dust, sea-salt, and black carbon in the atmosphere, we developed an integrated package of aerosol component retrieval algorithms, which have already been developed or are being developed, to estimate vertical profiles of the aerosol components. This package applies to the other ground-based lidar network data (e.g., EARLINET and satellite-borne lidar data (e.g., CALIOP/CALIPSO and ATLID/EarthCARE as well as the other lidar data of the AD-Net.

  17. The impact of erosion protection by Stone Dams on Salt-Marsh vegetation on Two Wadden Sea Barrier Islands

    NARCIS (Netherlands)

    Loon-Steensma, van J.M.; Slim, P.A.

    2013-01-01

    This paper describes and quantifies the effect of low stone dams on the extent and composition of salt-marsh habitats on two Dutch Wadden islands: Terschelling and Ameland. The stone dams were built to prevent erosion of the salt-marsh edge. Analyses of a series of aerial photographs taken between

  18. Chemical Thermodynamics of Aqueous Atmospheric Aerosols: Modeling and Microfluidic Measurements

    Science.gov (United States)

    Nandy, L.; Dutcher, C. S.

    2017-12-01

    Accurate predictions of gas-liquid-solid equilibrium phase partitioning of atmospheric aerosols by thermodynamic modeling and measurements is critical for determining particle composition and internal structure at conditions relevant to the atmosphere. Organic acids that originate from biomass burning, and direct biogenic emission make up a significant fraction of the organic mass in atmospheric aerosol particles. In addition, inorganic compounds like ammonium sulfate and sea salt also exist in atmospheric aerosols, that results in a mixture of single, double or triple charged ions, and non-dissociated and partially dissociated organic acids. Statistical mechanics based on a multilayer adsorption isotherm model can be applied to these complex aqueous environments for predictions of thermodynamic properties. In this work, thermodynamic analytic predictive models are developed for multicomponent aqueous solutions (consisting of partially dissociating organic and inorganic acids, fully dissociating symmetric and asymmetric electrolytes, and neutral organic compounds) over the entire relative humidity range, that represent a significant advancement towards a fully predictive model. The model is also developed at varied temperatures for electrolytes and organic compounds the data for which are available at different temperatures. In addition to the modeling approach, water loss of multicomponent aerosol particles is measured by microfluidic experiments to parameterize and validate the model. In the experimental microfluidic measurements, atmospheric aerosol droplet chemical mimics (organic acids and secondary organic aerosol (SOA) samples) are generated in microfluidic channels and stored and imaged in passive traps until dehydration to study the influence of relative humidity and water loss on phase behavior.

  19. Importance of biogeomorphic and spatial properties in assessing a tidal salt marsh vulnerability to sea-level rise

    Science.gov (United States)

    Thorne, Karen M.; Elliott-Fisk, Deborah L.; Wylie, Glenn D.; Perry, William M.; Takekawa, John Y.

    2014-01-01

    We evaluated the biogeomorphic processes of a large (309 ha) tidal salt marsh and examined factors that influence its ability to keep pace with relative sea-level rise (SLR). Detailed elevation data from 1995 and 2008 were compared with digital elevation models (DEMs) to assess marsh surface elevation change during this time. Overall, 37 % (113 ha) of the marsh increased in elevation at a rate that exceeded SLR, whereas 63 % (196 ha) of the area did not keep pace with SLR. Of the total area, 55 % (169 ha) subsided during the study period, but subsidence varied spatially across the marsh surface. To determine which biogeomorphic and spatial factors contributed to measured elevation change, we collected soil cores and determined percent and origin of organic matter (OM), particle size, bulk density (BD), and distance to nearest bay edge, levee, and channel. We then used Akaike Information Criterion (AICc) model selection to assess those variables most important to determine measured elevation change. Soil stable isotope compositions were evaluated to assess the source of the OM. The samples had limited percent OM by weight (-3, indicating that the soils had high mineral content with a relatively low proportion of pore space. The most parsimonious model with the highest AICc weight (0.53) included distance from bay's edge (i.e., lower intertidal) and distance from levee (i.e., upper intertidal). Close proximity to sediment source was the greatest factor in determining whether an area increased in elevation, whereas areas near landward levees experienced subsidence. Our study indicated that the ability of a marsh to keep pace with SLR varied across the surface, and assessing changes in elevation over time provides an alternative method to long-term accretion monitoring. SLR models that do not consider spatial variability of biogeomorphic and accretion processes may not correctly forecast marsh drowning rates, which may be especially true in modified and urbanized

  20. Aerosol composition, chemistry, and source characterization during the 2008 VOCALS Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.; Springston, S.; Jayne, J.; Wang, J.; Senum, G.; Hubbe, J.; Alexander, L.; Brioude, J.; Spak, S.; Mena-Carrasco, M.; Kleinman, L.; Daum, P.

    2010-03-15

    Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+ rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only {approx}0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the equivalency of Na+, and are externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on sea-salt aerosols, responsible for the Cl- deficit. Dust particles appeared to play a minor role, judging from the small volume differences between that derived from the observed mass concentrations and that calculated based on particle size distributions. Because SO42- concentrations were substantial ({approx}0.5 - {approx}3 {micro}g/m3) with a strong gradient (highest near the shore), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., {le} 40 parts per trillion and <0.05 {micro}g/m3, respectively), the observed SO42- aerosols are believed to be primarily of terrestrial origin. Back trajectory calculations indicate sulfur emissions from smelters and power plants along coastal regions of Peru and Chile are the main sources of these SO4- aerosols. However, compared to observations, model

  1. Retrieving simulated volcanic, desert dust and sea-salt particle properties from two/three-component particle mixtures using UV-VIS polarization lidar and T matrix

    Directory of Open Access Journals (Sweden)

    G. David

    2013-07-01

    Full Text Available During transport by advection, atmospheric nonspherical particles, such as volcanic ash, desert dust or sea-salt particles experience several chemical and physical processes, leading to a complex vertical atmospheric layering at remote sites where intrusion episodes occur. In this paper, a new methodology is proposed to analyse this complex vertical layering in the case of a two/three-component particle external mixtures. This methodology relies on an analysis of the spectral and polarization properties of the light backscattered by atmospheric particles. It is based on combining a sensitive and accurate UV-VIS polarization lidar experiment with T-matrix numerical simulations and air mass back trajectories. The Lyon UV-VIS polarization lidar is used to efficiently partition the particle mixture into its nonspherical components, while the T-matrix method is used for simulating the backscattering and depolarization properties of nonspherical volcanic ash, desert dust and sea-salt particles. It is shown that the particle mixtures' depolarization ratio δ p differs from the nonspherical particles' depolarization ratio δns due to the presence of spherical particles in the mixture. Hence, after identifying a tracer for nonspherical particles, particle backscattering coefficients specific to each nonspherical component can be retrieved in a two-component external mixture. For three-component mixtures, the spectral properties of light must in addition be exploited by using a dual-wavelength polarization lidar. Hence, for the first time, in a three-component external mixture, the nonsphericity of each particle is taken into account in a so-called 2β + 2δ formalism. Applications of this new methodology are then demonstrated in two case studies carried out in Lyon, France, related to the mixing of Eyjafjallajökull volcanic ash with sulfate particles (case of a two-component mixture and to the mixing of dust with sea-salt and water-soluble particles

  2. An integrated modeling study on the effects of mineral dust and sea salt particles on clouds and precipitation

    Directory of Open Access Journals (Sweden)

    S. Solomos

    2011-01-01

    Full Text Available This report addresses the effects of pollution on the development of precipitation in clean ("pristine" and polluted ("hazy" environments in the Eastern Mediterranean by using the Integrated Community Limited Area Modeling System (ICLAMS (an extended version of the Regional Atmospheric Modeling System, RAMS. The use of this model allows one to investigate the interactions of the aerosols with cloud development. The simulations show that the onset of precipitation in hazy clouds is delayed compared to pristine conditions. Adding small concentrations of GCCN to polluted clouds promotes early-stage rain. The addition of GCCN to pristine clouds has no effect on precipitation amounts. Topography was found to be more important for the distribution of precipitation than aerosol properties. Increasing by 15% the concentration of hygroscopic dust particles for a case study over the Eastern Mediterranean resulted in more vigorous convection and more intense updrafts. The clouds that were formed extended about three kilometers higher, delaying the initiation of precipitation by one hour. Prognostic treatment of the aerosol concentrations in the explicit cloud droplet nucleation scheme of the model, improved the model performance for the twenty-four hour accumulated precipitation. The spatial distribution and the amounts of precipitation were found to vary greatly between the different aerosol scenarios. These results indicate the large uncertainty that remains and the need for more accurate description of aerosol feedbacks in atmospheric models and climate change predictions.

  3. The composition and variability of atmospheric aerosol over Southeast Asia during 2008

    Directory of Open Access Journals (Sweden)

    W. Trivitayanurak

    2012-01-01

    Full Text Available We use a nested version of the GEOS-Chem global 3-D chemistry transport model to better understand the composition and variation of aerosol over Borneo and the broader Southeast Asian region in conjunction with aircraft and satellite observations. Our focus on Southeast Asia reflects the importance of this region as a source of reactive organic gases and aerosols from natural forests, biomass burning, and food and fuel crops. We particularly focus on July 2008 when the UK BAe-146 research aircraft was deployed over northern Malaysian Borneo as part of the ACES/OP3 measurement campaign. During July 2008 we find using the model that Borneo (defined as Borneo Island and the surrounding Indonesian islands was a net exporter of primary organic aerosol (42 kT and black carbon aerosol (11 kT. We find only 13% of volatile organic compound oxidation products partition to secondary organic aerosol (SOA, with Borneo being a net exporter of SOA (15 kT. SOA represents approximately 19% of the total organic aerosol over the region. Sulphate is mainly from aqueous-phase oxidation (68%, with smaller contributions from gas-phase oxidation (15% and advection into the regions (14%. We find that there is a large source of sea salt, as expected, but this largely deposits within the region; we find that dust aerosol plays only a relatively small role in the aerosol burden. In contrast to coincident surface measurements over Northern Borneo that find a pristine environment with evidence for substantial biogenic SOA formation we find that the free troposphere is influenced by biomass burning aerosol transported from the northwest of the Island and further afield. We find several transport events during July 2008 over Borneo associated with elevated aerosol concentrations, none of which coincide with the aircraft flights. We use MODIS aerosol optical depths (AOD data and the model to put the July campaign into a longer temporal perspective. We find that Borneo is where

  4. The composition and variability of atmospheric aerosol over Southeast Asia during 2008

    Science.gov (United States)

    Trivitayanurak, W.; Palmer, P. I.; Barkley, M. P.; Robinson, N. H.; Coe, H.; Oram, D. E.

    2012-01-01

    We use a nested version of the GEOS-Chem global 3-D chemistry transport model to better understand the composition and variation of aerosol over Borneo and the broader Southeast Asian region in conjunction with aircraft and satellite observations. Our focus on Southeast Asia reflects the importance of this region as a source of reactive organic gases and aerosols from natural forests, biomass burning, and food and fuel crops. We particularly focus on July 2008 when the UK BAe-146 research aircraft was deployed over northern Malaysian Borneo as part of the ACES/OP3 measurement campaign. During July 2008 we find using the model that Borneo (defined as Borneo Island and the surrounding Indonesian islands) was a net exporter of primary organic aerosol (42 kT) and black carbon aerosol (11 kT). We find only 13% of volatile organic compound oxidation products partition to secondary organic aerosol (SOA), with Borneo being a net exporter of SOA (15 kT). SOA represents approximately 19% of the total organic aerosol over the region. Sulphate is mainly from aqueous-phase oxidation (68%), with smaller contributions from gas-phase oxidation (15%) and advection into the regions (14%). We find that there is a large source of sea salt, as expected, but this largely deposits within the region; we find that dust aerosol plays only a relatively small role in the aerosol burden. In contrast to coincident surface measurements over Northern Borneo that find a pristine environment with evidence for substantial biogenic SOA formation we find that the free troposphere is influenced by biomass burning aerosol transported from the northwest of the Island and further afield. We find several transport events during July 2008 over Borneo associated with elevated aerosol concentrations, none of which coincide with the aircraft flights. We use MODIS aerosol optical depths (AOD) data and the model to put the July campaign into a longer temporal perspective. We find that Borneo is where the model

  5. Properties of aerosols and formation mechanisms over southern China during the monsoon season

    Science.gov (United States)

    Chen, Weihua; Wang, Xuemei; Blake Cohen, Jason; Zhou, Shengzhen; Zhang, Zhisheng; Chang, Ming; Chan, Chuen-Yu

    2016-10-01

    Measurements of size-resolved aerosols from 0.25 to 18 µm were conducted at three sites (urban, suburban and background sites) and used in tandem with an atmospheric transport model to study the size distribution and formation of atmospheric aerosols in southern China during the monsoon season (May-June) in 2010. The mass distribution showed the majority of chemical components were found in the smaller size bins (water and anticorrelated with atmospheric SO2, hinting at aqueous-phase reactions being the main formation pathway. Nitrate was the only major species that showed a bimodal distribution at the urban site and was dominated by the coarse mode in the other two sites, suggesting that an important component of nitrate formation is chloride depletion of sea salt transported from the South China Sea. In addition to these aqueous-phase reactions and interactions with sea salt aerosols, new particle formation, chemical aging, and long-range transport from upwind urban or biomass burning regions was also found to be important in at least some of the sites on some of the days. This work therefore summarizes the different mechanisms that significantly impact the aerosol chemical composition during the monsoon over southern China.

  6. Influence of different salting processes on the evolution of the volatile metabolites of vacuum-packed fillets of farmed and wild sea bass (Dicentrarchus labrax) stored under refrigeration conditions: a study by SPME-GC/MS.

    Science.gov (United States)

    Vidal, Natalia P; Manzanos, María J; Goicoechea, Encarnación; Guillén, María D

    2017-02-01

    Fish shelf-life extension is a topic of great interest. In this study the behaviour of salted and unsalted farmed and wild European sea bass (Dicentrarchus labrax) fillets during storage was analysed through the evolution of their volatile metabolites. Farmed and wild sea bass fillets were brine-salted for 15 or 75 min, or dry-salted, vacuum-packed and stored at 4 °C for up to 1 month, and their headspaces were studied by Solid Phase Micro extraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). At the same storage time, unsalted wild fillets contained, in general, a higher number and abundance of volatile compounds coming from microbiological or endogenous enzymatic activity than unsalted farmed ones. The more intense the salting, the lower the number and abundance of microbiological spoilage metabolites, especially in wild samples. The appearance of oxidation metabolites only in dry-salted wild samples evidences that this kind of salting provokes a certain oxidation in these samples. The better performance of farmed than wild fillets suggests that salted farmed fillets, vacuum-packed and stored under refrigeration conditions, could be a successful alternative to diversify the presence of sea bass in the market. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Directory of Open Access Journals (Sweden)

    T. Holzer-Popp

    2013-08-01

    photometer observations for the different versions of each algorithm globally (land and coastal and for three regions with different aerosol regimes. The analysis allowed for an assessment of sensitivities of all algorithms, which helped define the best algorithm versions for the subsequent round robin exercise; all algorithms (except for MERIS showed some, in parts significant, improvement. In particular, using common aerosol components and partly also a priori aerosol-type climatology is beneficial. On the other hand the use of an AATSR-based common cloud mask meant a clear improvement (though with significant reduction of coverage for the MERIS standard product, but not for the algorithms using AATSR. It is noted that all these observations are mostly consistent for all five analyses (global land, global coastal, three regional, which can be understood well, since the set of aerosol components defined in Sect. 3.1 was explicitly designed to cover different global aerosol regimes (with low and high absorption fine mode, sea salt and dust.

  8. Overview and preliminary results of the Surface Ocean Aerosol Production (SOAP campaign

    Directory of Open Access Journals (Sweden)

    C. S. Law

    2017-11-01

    , contaminant markers and a common aerosol inlet facilitated multi-sensor measurement of uncontaminated air. Aerosol characterization identified variable Aitken mode and consistent submicron-sized accumulation and coarse modes. Submicron aerosol mass was dominated by secondary particles containing ammonium sulfate/bisulfate under light winds, with an increase in sea salt under higher wind speeds. MBL measurements and chamber experiments identified a significant organic component in primary and secondary aerosols. Comparison of SOAP aerosol number and size distributions reveals an underprediction in GLOMAP (GLObal Model of Aerosol Processes-mode aerosol number in clean marine air masses, suggesting a missing marine aerosol source in the model. The SOAP data will be further examined for evidence of nucleation events and also to identify relationships between MBL composition and surface ocean biogeochemistry that may provide potential proxies for aerosol precursors and production.

  9. Aerosol transport from Chiang Mai, Thailand to Mt. Lulin, Taiwan - Implication of aerosol aging during long-range transport

    Science.gov (United States)

    Chuang, Ming-Tung; Lee, Chung-Te; Chou, Charles C.-K.; Engling, Guenter; Chang, Shih-Yu; Chang, Shuenn-Chin; Sheu, Guey-Rong; Lin, Neng-Huei; Sopajaree, Khajornsak; Chang, You-Jia; Hong, Guo-Jun

    2016-07-01

    The transport of biomass burning (BB) aerosol from Indochina may cause a potential effect on climate change in Southeast Asia, East Asia, and the Western Pacific. Up to now, the understanding of BB aerosol composition modification during long-range transport (LRT) is still very limited due to the lack of observational data. In this study, atmospheric aerosols were collected at the Suthep/Doi Ang Khang (DAK) mountain sites in Chiang Mai, Thailand and the Lulin Atmospheric Background Station (Mt. Lulin) in central Taiwan from March to April 2010 and from February to April 2013, respectively. During the study period, an upwind and downwind relationship between the Suthep/DAK and Lulin sites (2400 km apart) was validated by backward trajectories. Comprehensive aerosol properties were resolved for PM2.5 water-soluble inorganic ions, carbonaceous content, water-soluble/insoluble organic carbon (WSOC/WIOC), dicarboxylic acids and their salts (DCAS), and anhydrosugars. A Modification Factor (MF) is proposed by employing non-sea-salt potassium ion (nss-K+) or fractionalized elemental carbon evolved at 580 °C after pyrolized OC correction (EC1-OP) as a BB aerosol tracer to evaluate the mass fraction changes of aerosol components from source to receptor regions during LRT. The MF values of nss-SO42-, NH4+, NO3-, OC1 (fractionalized organic carbon evolved from room temperature to 140 °C), OP (pyrolized OC fraction), DCAS, and WSOC were above unity, which indicated that these aerosol components were enhanced during LRT as compared with those in the near-source region. In contrast, the MF values of anhydrosugars ranged from 0.1 to 0.3, indicating anhydrosugars have degraded during LRT.

  10. Two-Column Aerosol Project (TCAP) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Larry K [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-05-01

    This study included the deployment of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Mobile Facility (AMF), ARM Mobile Aerosol Observing System (MAOS) and the ARM Aerial Facility (AAF). The study was a collaborative effort involving scientists from DOE national laboratories, NOAA, NASA, and universities. The AAF and MAOS were deployed for two approximately month-long Intensive Operational Periods (IOPs) conducted in June 2012 and February 2013. Seasonal differences in the aerosol chemical and optical properties observed using the AMF, AAF, and MAOS are presented in this report. The total mass loading of aerosol is found to be much greater in the summer than in the winter, with the difference associated with greater amounts of organic aerosol. The mass fraction of organic aerosol is much reduced in the winter, when sulfate is the dominant aerosol type. Surprisingly, very little sea-salt aerosol was observed in the summer. In contrast, much more sea salt aerosol was observed in the winter. The mass loading of black carbon is nearly the same in both seasons. These differences lead to a relative increase in the aerosol light absorption in the winter and an associated decrease in observed single-scattering albedo. Measurements of aerosol mixing state were made using a single-particle mass spectrometer, which showed that the majority of the summertime aerosol consisted of organic compounds mixed with various amounts of sulfate. A number of other findings are also summarized in the report, including: impact of aerosol layers aloft on the column aerosol optical depth; documentation of the aerosol properties at the AMF; differences in the aerosol properties associated with both columns, which are not systematic but reflect the complicated meteorological and chemical processes that impact aerosol as it is advected away from North America; and new instruments and data-processing techniques for measuring both aerosol and

  11. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  12. Water soluble organic carbon in aerosols (PM1, PM2.5, PM10) and various precipitation forms (rain, snow, mixed) over the southern Baltic Sea station.

    Science.gov (United States)

    Witkowska, Agnieszka; Lewandowska, Anita U

    2016-12-15

    In the urbanized coastal zone of the Southern Baltic, complex measurements of water soluble organic carbon (WSOC) were conducted between 2012 and 2015, involving atmospheric precipitation in its various forms (rain, snow, mixed) and PM1, PM2.5 and PM10 aerosols. WSOC constituted about 60% of the organic carbon mass in aerosols of various sizes. The average concentration of WSOC was equal to 2.6μg∙m -3 in PM1, 3.6μg∙m -3 in PM2.5 and 4.4μg∙m -3 in PM10. The lowest concentration of WSOC was noted in summer as a result of effective removal of this compound with rainfall. The highest WSOC concentrations in PM2.5 and PM10 aerosols were measured in spring, which should be associated with developing vegetation on land and in the sea. On the other hand, the highest WSOC concentrations in PM1 occurred in winter at low air temperatures and greatest atmospheric stability, when there were increased carbon emissions from fuel combustion in the communal-utility sector and from transportation. WSOC concentrations in precipitation were determined by its form. Mixed precipitation turned out to be the richest in soluble organic carbon (5.1mg·dm -3 ), while snow contained the least WSOC (1.7mg·dm -3 ). Snow and rain cleaned carbon compounds from the atmosphere more effectively when precipitation lasted longer than 24h, while in the case of mixed precipitation WSOC was removed most effectively within the first 24h. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Aerosols at the poles: an AeroCom Phase II multi-model evaluation

    Directory of Open Access Journals (Sweden)

    M. Sand

    2017-10-01

    Full Text Available Atmospheric aerosols from anthropogenic and natural sources reach the polar regions through long-range transport and affect the local radiation balance. Such transport is, however, poorly constrained in present-day global climate models, and few multi-model evaluations of polar anthropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD at 550 nm from simulations with 16 global aerosol models from the AeroCom Phase II model intercomparison project with available observations at both poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the intermodel spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species: black carbon (BC from fossil fuel and biomass burning, sulfate, organic aerosols (OAs, dust, and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOAs, we document the role of these aerosols at high latitudes.The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in winter (sea-salt and spring (dust, whereas AOD from anthropogenic aerosols peaks in late spring and summer. The models produce a median annual mean AOD of 0.07 in the Arctic (defined here as north of 60° N. The models also predict a noteworthy aerosol transport to the Antarctic (south of 70° S with a resulting AOD varying between 0.01 and 0.02. The models have estimated the shortwave anthropogenic radiative forcing contributions to the direct aerosol effect (DAE associated with BC and OA from fossil fuel and biofuel (FF, sulfate, SOAs, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modelled annual mean DAE is slightly negative (−0.12 W m−2, dominated by a positive BC FF DAE in spring and a negative sulfate DAE in summer. The Antarctic DAE is governed by BC FF. We perform sensitivity

  14. A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2005-01-01

    Full Text Available A GLObal Model of Aerosol Processes (GLOMAP has been developed as an extension to the TOMCAT 3-D Eulerian off-line chemical transport model. GLOMAP simulates the evolution of the global aerosol size distribution using a sectional two-moment scheme and includes the processes of aerosol nucleation, condensation, growth, coagulation, wet and dry deposition and cloud processing. We describe the results of a global simulation of sulfuric acid and sea spray aerosol. The model captures features of the aerosol size distribution that are well established from observations in the marine boundary layer and free troposphere. Modelled condensation nuclei (CN>3nm vary between about 250–500 cm-3 in remote marine boundary layer regions and are generally in good agreement with observations. Modelled continental CN concentrations are lower than observed, which may be due to lack of some primary aerosol sources or the neglect of nucleation mechanisms other than binary homogeneous nucleation of sulfuric acid-water particles. Remote marine CN concentrations increase to around 2000–10 000 cm (at standard temperature and pressure in the upper troposphere, which agrees with typical observed vertical profiles. Cloud condensation nuclei (CCN at 0.2% supersaturation vary between about 1000 cm-3 in polluted regions and between 10 and 500 cm-3 in the remote marine boundary layer. New particle formation through sulfuric acid-water binary nucleation occurs predominantly in the upper troposphere, but the model results show that these particles contribute greatly to aerosol concentrations in the marine boundary layer. For this sulfur-sea salt system it is estimated that sea spray emissions account for only ~10% of CCN in the tropical marine boundary layer, but between 20 and 75% in the mid-latitude Southern Ocean. In a run with only natural sulfate and sea salt emissions the global mean surface CN concentration is more than 60% of that from a run with 1985 anthropogenic

  15. Draft Genome of Scalindua rubra, Obtained from the Interface Above the Discovery Deep Brine in the Red Sea, Sheds Light on Potential Salt Adaptation Strategies in Anammox Bacteria.

    Science.gov (United States)

    Speth, Daan R; Lagkouvardos, Ilias; Wang, Yong; Qian, Pei-Yuan; Dutilh, Bas E; Jetten, Mike S M

    2017-07-01

    Several recent studies have indicated that members of the phylum Planctomycetes are abundantly present at the brine-seawater interface (BSI) above multiple brine pools in the Red Sea. Planctomycetes include bacteria capable of anaerobic ammonium oxidation (anammox). Here, we investigated the possibility of anammox at BSI sites using metagenomic shotgun sequencing of DNA obtained from the BSI above the Discovery Deep brine pool. Analysis of sequencing reads matching the 16S rRNA and hzsA genes confirmed presence of anammox bacteria of the genus Scalindua. Phylogenetic analysis of the 16S rRNA gene indicated that this Scalindua sp. belongs to a distinct group, separate from the anammox bacteria in the seawater column, that contains mostly sequences retrieved from high-salt environments. Using coverage- and composition-based binning, we extracted and assembled the draft genome of the dominant anammox bacterium. Comparative genomic analysis indicated that this Scalindua species uses compatible solutes for osmoadaptation, in contrast to other marine anammox bacteria that likely use a salt-in strategy. We propose the name Candidatus Scalindua rubra for this novel species, alluding to its discovery in the Red Sea.

  16. Online Simulations of Global Aerosol Distributions in the NASA GEOS-4 Model and Comparisons to Satellite and Ground-Based Aerosol Optical Depth

    Science.gov (United States)

    Colarco, Peter; daSilva, Arlindo; Chin, Mian; Diehl, Thomas

    2010-01-01

    We have implemented a module for tropospheric aerosols (GO CART) online in the NASA Goddard Earth Observing System version 4 model and simulated global aerosol distributions for the period 2000-2006. The new online system offers several advantages over the previous offline version, providing a platform for aerosol data assimilation, aerosol-chemistry-climate interaction studies, and short-range chemical weather forecasting and climate prediction. We introduce as well a methodology for sampling model output consistently with satellite aerosol optical thickness (AOT) retrievals to facilitate model-satellite comparison. Our results are similar to the offline GOCART model and to the models participating in the AeroCom intercomparison. The simulated AOT has similar seasonal and regional variability and magnitude to Aerosol Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer, and Multiangle Imaging Spectroradiometer observations. The model AOT and Angstrom parameter are consistently low relative to AERONET in biomass-burning-dominated regions, where emissions appear to be underestimated, consistent with the results of the offline GOCART model. In contrast, the model AOT is biased high in sulfate-dominated regions of North America and Europe. Our model-satellite comparison methodology shows that diurnal variability in aerosol loading is unimportant compared to sampling the model where the satellite has cloud-free observations, particularly in sulfate-dominated regions. Simulated sea salt burden and optical thickness are high by a factor of 2-3 relative to other models, and agreement between model and satellite over-ocean AOT is improved by reducing the model sea salt burden by a factor of 2. The best agreement in both AOT magnitude and variability occurs immediately downwind of the Saharan dust plume.

  17. Continuous 25-yr aerosol records at coastal Antarctica – I: inter-annual variability of ionic compounds and links to climate indices

    OpenAIRE

    Weller, Rolf; Wagenbach, Dietmar; Legrand, Michel; Elsässer, Christoph; Tian-Kunze, Xiangshan; König-Langlo, Gert

    2011-01-01

    The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non–sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (−3.6 ± 2.5% per year between 1983 and 1993 and +4.0 ± 3.2% per year from 1993–2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses...

  18. Single-particle characterization of summertime Antarctic aerosols collected at King George Island using quantitative energy-dispersive electron probe X-ray microanalysis and attenuated total reflection Fourier transform-infrared imaging techniques.

    Science.gov (United States)

    Maskey, Shila; Geng, Hong; Song, Young-Chul; Hwang, Heejin; Yoon, Young-Jun; Ahn, Kang-Ho; Ro, Chul-Un

    2011-08-01

    Single-particle characterization of Antarctic aerosols was performed to investigate the impact of marine biogenic sulfur species on the chemical compositions of sea-salt aerosols in the polar atmosphere. Quantitative energy-dispersive electron probe X-ray microanalysis was used to characterize 2900 individual particles in 10 sets of aerosol samples collected between March 12 and 16, 2009 at King Sejong Station, a Korean scientific research station located at King George Island in the Antarctic. Two size modes of particles, i.e., PM(2.5-10) and PM(1.0-2.5), were analyzed, and four types of particles were identified, with sulfur-containing sea-salt particles being the most abundant, followed by genuine sea-salt particles without sulfur species, iron-containing particles, and other species including CaCO(3)/CaMg(CO(3))(2), organic carbon, and aluminosilicates. When a sulfur-containing sea-salt particle showed an atomic concentration ratio of sulfur to sodium of >0.083 (seawater ratio), it is regarded as containing nonsea-salt sulfate (nss-SO(4)(2-)) and/or methanesulfonate (CH(3)SO(3)(-)), which was supported by attenuated total reflection Fourier transform-infrared imaging measurements. These internal mixture particles of sea-salt/CH(3)SO(3)(-)/SO(4)(2-) were very frequently encountered. As nitrate-containing particles were not encountered, and the air-masses for all of the samples originated from the Pacific Ocean (based on 5-day backward trajectories), the oxidation of dimethylsulfide (DMS) emitted from phytoplanktons in the ocean is most likely to be responsible for the formation of the mixed sea-salt/CH(3)SO(3)(-)/SO(4)(2-) particles.

  19. Sensitivity of modelled sulfate aerosol and its radiative effect on climate to ocean DMS concentration and air–sea flux

    Directory of Open Access Journals (Sweden)

    J.-E. Tesdal

    2016-09-01

    Full Text Available Dimethylsulfide (DMS is a well-known marine trace gas that is emitted from the ocean and subsequently oxidizes to sulfate in the atmosphere. Sulfate aerosols in the atmosphere have direct and indirect effects on the amount of solar radiation reaching the Earth's surface. Thus, as a potential source of sulfate, ocean efflux of DMS needs to be accounted for in climate studies. Seawater concentration of DMS is highly variable in space and time, which in turn leads to high spatial and temporal variability in ocean DMS emissions. Because of sparse sampling (in both space and time, large uncertainties remain regarding ocean DMS concentration. In this study, we use an atmospheric general circulation model with explicit aerosol chemistry (CanAM4.1 and several climatologies of surface ocean DMS concentration to assess uncertainties about the climate impact of ocean DMS efflux. Despite substantial variation in the spatial pattern and seasonal evolution of simulated DMS fluxes, the global-mean radiative effect of sulfate is approximately linearly proportional to the global-mean surface flux of DMS; the spatial and temporal distribution of ocean DMS efflux has only a minor effect on the global radiation budget. The effect of the spatial structure, however, generates statistically significant changes in the global-mean concentrations of some aerosol species. The effect of seasonality on the net radiative effect is larger than that of spatial distribution and is significant at global scale.

  20. Salton Sea geothermal field as a natural analog for the near-field in a salt high-level nuclear waste repository

    International Nuclear Information System (INIS)

    Elders, W.A.; Moody, J.B.; Battelle Memorial Inst., Columbus, OH)

    1984-01-01

    The Salton Sea Geothermal Field (SSGF), on the delta of the Colorado River in southern California, is being studied as a natural analog for the near-field environment of proposed nuclear waste repositories in salt. A combination of mineralogical and geochemical methods is being employed to develop a three-dimenisonal picture of temperature, salinity, lithology, mineralogy, and chemistry of reactions between the reservoir rocks and the hot brines. Our aim is to obtain quantitative data on mineral stabilities and on mobilities of the naturally occurring radionuclides of concern in Commercial High-Level Waste (CHLW). These data will be used to validate the EQ3/6 geochemical code under development to model the salt near-field repository behavior. Maximum temperatures encountered in wells in the SSGF equal or exceed peak temperatures expected in a salt repository. Brines produced from these wells have major element chemistry similar to brines from candidate salt sites. Relative to the rocks, these brines are enriched in Na, Mn, Sr, Ra, and Po, depleted in Ba, Si, Mg, Ti, and Al, and strongly depleted in U and Th. However, the unaltered rocks contain only about 2 to 3 ppm of U and 4 to 12 ppm of Th, largely in detrital epidotes and zircons. Samples of hydrothermally altered rocks from a wide range of temperature and salinity show rather similar uniform low concentrations of these elements, even when authigenic illite, chlorite, ipidote and feldspar are present. These observations suggest that U and Th are relatively immobile in these hot brines. However, Ra, Po, Cs, and Sr are relatively mobile. Work is continuing to document naturally occurring radionuclide partitioning between SSGF minears and brine over a range of temperature, salinity, and lithology. 8 refs., 7 figs., 2 tabs

  1. Effects of salinity and sea salt type on egg activation, fertilization, buoyancy and early embryology of European eel, Anguilla anguilla

    DEFF Research Database (Denmark)

    Sørensen, Sune Riis; Butts, Ian; Munk, Peter

    2016-01-01

    sizes, while the remaining four salt types resulted in smaller eggs. All salt types except NaCl treatments led to high fertilization rates and had no effect on fertilization success as well as egg neutral buoyancies at 7 h post-fertilization. The study points to the importance of considering ionic...... and egg buoyancy. Egg diameter after activation, using natural seawater adjusted to different salinities, varied among female eels, but no consistent pattern emerged. Activation salinities between 30–40 practical salinity unit (psu) produced higher quality eggs and generally larger egg diameters. Chorion...

  2. Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

    Science.gov (United States)

    Maroni, V.A.; von Winbush, S.

    1987-05-01

    A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

  3. The use of airborne electromagnetic for efficient mapping of salt water intrusion and outflow to the sea

    DEFF Research Database (Denmark)

    Auken, Esben; Kirkegaard, Casper; Ribeiro, Joana

    2010-01-01

    Airborne electromagnetic (AEM) is an efficient tool for mapping groundwater resources in sedimentary environments. AEM delivers a very high data coverage and results in high-resolution electrical images of the subsurface. In particular the time domain methods (TEM) are well suited for mapping o0f...... not only the salt-fresh water boundary in the coastal zone, but also the mixing of fresh-salt-water on the seaside. Even freshwater layers under several meters of brackish water can be mapped. Sufficient depth of investigation is obtained by time domain methods as they have a significant higher transmitter...

  4. Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

    Science.gov (United States)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

    2016-07-01

    Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act

  5. PM 2.5 mass concentrations in comparison with aerosol optical depths over the Arabian Sea and Indian Ocean during winter monsoon

    Science.gov (United States)

    Ramachandran, S.

    An analysis of PM 2.5 mass concentrations and 0.5 μm aerosol optical depths (AODs) during the Northeast winter monsoon seasons of 1996-2000 is performed and intercompared. AODs are found to show diurnal variations over Coastal India (CI) (west coast) while they are relatively smooth over the Arabian Sea (AS) (5-20°N) and tropical Indian Ocean (TIO) (5°N-20°S). PM 2.5, PM 10 and total mass concentrations show less variations in a day over these oceanic regions. Columnar AODs are found to increase with an increase in the marine boundary layer aerosol concentrations over CI and AS while an opposite trend is seen over TIO. The yearly-mean AODs and mass concentrations are found to increase over CI and AS, over TIO the mass concentrations increased while the AODs decreased during 1996-2000. It is found from the 7-days air back trajectory analyses that at different altitudes air masses can originate from different source regions leading to changes in chemical, physical and optical characteristics of the aerosol between the surface and column. The differences in the surface and columnar measurements could also occur due to changes in the meteorological conditions, wind patterns, in addition to changes in production and subsequently the transport of aerosols. Least-squares fits to the above intercomparison resulted in intercepts of 0.24 and 0.22 over CI and AS indicating that the background AODs over these oceanic regions are higher. An examination of the daily-mean wind speeds and PM 2.5 mass concentrations yielded an index of wind dependence of 0.04 for AS and 0.07 for TIO. The background PM 2.5 mass concentrations are also found to be high at 36 and 25 μg m -3 over AS and TIO, respectively, indicating a stronger influence from the continent. Frequency distribution figures show that 28% of the PM 2.5 values over CI lie in the 60-80 μg m -3 range. Over AS the dominant mode of distribution is 40-60 μg m -3 with a peak value of 42%. Over TIO PM 2.5 values are found to

  6. MIRAGE: Model description and evaluation of aerosols and trace gases

    Science.gov (United States)

    Easter, Richard C.; Ghan, Steven J.; Zhang, Yang; Saylor, Rick D.; Chapman, Elaine G.; Laulainen, Nels S.; Abdul-Razzak, Hayder; Leung, L. Ruby; Bian, Xindi; Zaveri, Rahul A.

    2004-10-01

    The Model for Integrated Research on Atmospheric Global Exchanges (MIRAGE) modeling system, designed to study the impacts of anthropogenic aerosols on the global environment, is described. MIRAGE consists of a chemical transport model coupled online with a global climate model. The chemical transport model simulates trace gases, aerosol number, and aerosol chemical component mass (sulfate, methane sulfonic acid (MSA), organic matter, black carbon (BC), sea salt, and mineral dust) for four aerosol modes (Aitken, accumulation, coarse sea salt, and coarse mineral dust) using the modal aerosol dynamics approach. Cloud-phase and interstitial aerosol are predicted separately. The climate model, based on Community Climate Model, Version 2 (CCM2), has physically based treatments of aerosol direct and indirect forcing. Stratiform cloud water and droplet number are simulated using a bulk microphysics parameterization that includes aerosol activation. Aerosol and trace gas species simulated by MIRAGE are presented and evaluated using surface and aircraft measurements. Surface-level SO2 in North American and European source regions is higher than observed. SO2 above the boundary layer is in better agreement with observations, and surface-level SO2 at marine locations is somewhat lower than observed. Comparison with other models suggests insufficient SO2 dry deposition; increasing the deposition velocity improves simulated SO2. Surface-level sulfate in North American and European source regions is in good agreement with observations, although the seasonal cycle in Europe is stronger than observed. Surface-level sulfate at high-latitude and marine locations, and sulfate above the boundary layer, are higher than observed. This is attributed primarily to insufficient wet removal; increasing the wet removal improves simulated sulfate at remote locations and aloft. Because of the high sulfate bias, radiative forcing estimates for anthropogenic sulfur given in 2001 by S. J. Ghan and

  7. The role of salt tectonics and overburden in the generation of overpressure in the Dutch North Sea area

    NARCIS (Netherlands)

    Nelskamp, S.; Verweij, J.M.; Witmans, N.

    2012-01-01

    In this paper we study the effects of timing of salt movement and mechanical compaction on the generation of overpressures in Mesozoic rocks. To that end we apply 2D basin modelling on two N-S trending cross sections in the Dutch Central Graben and Terschelling Basin, respectively. Several

  8. Moderate livestock grazing of salt, and brackish marshes benefits breeding birds along the mainland coast of the Wadden Sea

    NARCIS (Netherlands)

    Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Koffijberg, Kees; Dijkema, Kees S.; Bakker, Jan P.

    Our study investigated how bird species richness and abundance was related to livestock grazing on salt, and brackish marshes, with an emphasis on songbirds, and shorebirds. Survey areas with a high percentage cover of tall vegetation were assumed to have experienced lower livestock grazing

  9. Moderate livestock grazing of salt, and brackish marshes benefits breeding birds along the mainland coast of the Wadden Sea

    NARCIS (Netherlands)

    Mandema, F.S.; Tinbergen, J.M.; Ens, B.J.; Koffijberg, K.; Dijkema, K.S.; Bakker, J.P.

    2015-01-01

    Our study investigated how bird species richness and abundance was related to livestock grazing on salt, and brackish marshes, with an emphasis on songbirds, and shorebirds. Survey areas with a high percentage cover of tall vegetation were assumed to have experienced lower livestock grazing

  10. Adjoint sensitivity of global cloud droplet number to aerosol and dynamical parameters

    Directory of Open Access Journals (Sweden)

    V. A. Karydis

    2012-10-01

    Full Text Available We present the development of the adjoint of a comprehensive cloud droplet formation parameterization for use in aerosol-cloud-climate interaction studies. The adjoint efficiently and accurately calculates the sensitivity of cloud droplet number concentration (CDNC to all parameterization inputs (e.g., updraft velocity, water uptake coefficient, aerosol number and hygroscopicity with a single execution. The adjoint is then integrated within three dimensional (3-D aerosol modeling frameworks to quantify the sensitivity of CDNC formation globally to each parameter. Sensitivities are computed for year-long executions of the NASA Global Modeling Initiative (GMI Chemical Transport Model (CTM, using wind fields computed with the Goddard Institute for Space Studies (GISS Global Circulation Model (GCM II', and the GEOS-Chem CTM, driven by meteorological input from the Goddard Earth Observing System (GEOS of the NASA Global Modeling and Assimilation Office (GMAO. We find that over polluted (pristine areas, CDNC is more sensitive to updraft velocity and uptake coefficient (aerosol number and hygroscopicity. Over the oceans of the Northern Hemisphere, addition of anthropogenic or biomass burning aerosol is predicted to increase CDNC in contrast to coarse-mode sea salt which tends to decrease CDNC. Over the Southern Oceans, CDNC is most sensitive to sea salt, which is the main aerosol component of the region. Globally, CDNC is predicted to be less sensitive to changes in the hygroscopicity of the aerosols than in their concentration with the exception of dust where CDNC is very sensitive to particle hydrophilicity over arid areas. Regionally, the sensitivities differ considerably between the two frameworks and quantitatively reveal why the models differ considerably in their indirect forcing estimates.

  11. The street children of Manila are affected by early-in-life periodontal infection: description of a treatment modality: sea salt.

    Science.gov (United States)

    Michel, J F; Michel, M G; Nadan, J; Nowzari, H

    2013-01-01

    Thousands of street children of Manila are affected by early-in-life oral infection. The aim of the present investigation was to evaluate the effectiveness of a sea-salt mouthrinse solution in street children of Manila affected by mild to severe forms of periodontal disease. These children were all in need of special protection: abandoned, abused, exploited, neglected, orphaned, poor. During 3 oral-health missions in 2003, 2004 and 2005, 617 abandoned children (5 to 13 year-old), received oral examination at a non-sectarian child-caring institution in Metro Manila (Virlanie Foundation) by calibrated examiners. A treatment based on what could be done was proposed: 1. Teaching of a precise tooth brushing technique with sea-salt, controlled and reinforced every two days for one week by calibrated health educators, 2. The application of sea-salt water mouthrinse (2.5 gram in 20 ml). Periodontal measurements were repeated at the end of each mission. All children returned to child-caring institution for the followup examinations. In 2003, 10 male and 11 female (n=21) were diagnosed with aggressive periodontitis. In 2009 and 2010, none was affected by aggressive periodontitis. For all patients, the gingival index decreased from 1.08 at the first mission to 1.04 at the end of the second mission and 0.98 at the end of the third mission. The periodontal index decreased from 1.33 at the first mission to 0.98 at the second mission and 0.92 at the last mission. The present investigation confirms that prevention and early diagnosis can result in success with minimum cost. The provided oral health program empowered street children in the most desperate circumstances to be educated and become self-reliant, independent, and responsible. We propose here an antimicrobial approach which has a high degree of efficacy and tolerability, and can be implemented in virtually all parts of the world using low-cost resources.

  12. Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

    Directory of Open Access Journals (Sweden)

    B. Sič

    2015-02-01

    Full Text Available This paper deals with recent improvements to the global chemical transport model of Météo-France MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle that consists of updates to different aerosol parameterizations. MOCAGE only contains primary aerosol species: desert dust, sea salt, black carbon, organic carbon, and also volcanic ash in the case of large volcanic eruptions. We introduced important changes to the aerosol parameterization concerning emissions, wet deposition and sedimentation. For the emissions, size distribution and wind calculations are modified for desert dust aerosols, and a surface sea temperature dependant source function is introduced for sea salt aerosols. Wet deposition is modified toward a more physically realistic representation by introducing re-evaporation of falling rain and snowfall scavenging and by changing the in-cloud scavenging scheme along with calculations of precipitation cloud cover and rain properties. The sedimentation scheme update includes changes regarding the stability and viscosity calculations. Independent data from satellites (MODIS, SEVIRI, the ground (AERONET, EMEP, and a model inter-comparison project (AeroCom are compared with MOCAGE simulations and show that the introduced changes brought a significant improvement on aerosol representation, properties and global distribution. Emitted quantities of desert dust and sea salt, as well their lifetimes, moved closer towards values of AeroCom estimates and the multi-model average. When comparing the model simulations with MODIS aerosol optical depth (AOD observations over the oceans, the updated model configuration shows a decrease in the modified normalized mean bias (MNMB; from 0.42 to 0.10 and a better correlation (from 0.06 to 0.32 in terms of the geographical distribution and the temporal variability. The updates corrected a strong positive MNMB in the sea salt representation at high latitudes (from 0.65 to 0.16, and a negative MNMB in

  13. Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

    Science.gov (United States)

    Ro, Chul-Un; Kim, HyeKyeong; Oh, Keun-Young; Yea, Sun Kyung; Lee, Chong Bum; Jang, Meongdo; Van Grieken, René

    2002-11-15

    A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

  14. A51F-0123: Model Analysis of Tropospheric Aerosol Variability and Sources over the North Atlantic During NAAMES 2015-2016

    Science.gov (United States)

    Liu, Hongyu; Moore, Richard; Hostetler, Chris A.; Ferrare, Richard Anthony; Fairlie, Thomas Duncan; Hu, Youngxiang; Chen, Gao; Hair, Johnathan W.; Johnson, Matthew S.

    2016-01-01

    The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is a five-year Earth-Venture Suborbital-2 Mission to characterize the plankton ecosystems and their influences on remote marine aerosols, boundary layer clouds, and their implications for climate in the North Atlantic. While marine-sourced aerosols have been shown to make important contributions to surface aerosol loading, cloud condensation nuclei and ice nuclei concentrations over remote marine and coastal regions, it is still a challenge to differentiate the marine biogenic aerosol signal from the strong influence of continental pollution outflow. We examine here the spatiotemporal variability and quantify the sources of tropospheric aerosols over the North Atlantic during the first two phases (November 2015 and May-June 2016) of NAAMES using a state-of-the-art chemical transport model (GEOS-Chem). The model is driven by the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) from the NASA Global Modeling and Assimilation Office (GMAO). It includes sulfate-nitrate-ammonium aerosol thermodynamics coupled to ozone-NOx-hydrocarbon-aerosol chemistry, mineral dust, sea salt, elemental and organic carbon aerosols, and especially a recently implemented parameterization for the marine primary organic aerosol emission. The simulated aerosols over the North Atlantic are evaluated with available satellite (e.g., MODIS) observations of aerosol optical depths (AOD), and aircraft and ship aerosol measurements. We diagnose transport pathways for continental pollution outflow over the North Atlantic using carbon monoxide, an excellent tracer for anthropogenic pollution transport. We also conduct model perturbation experiments to quantify the relative contributions of terrestrial and oceanic sources to the aerosol loading, AOD, and their variability over the North Atlantic.

  15. Interactive effects of vegetation and sediment properties on erosion of salt marshes in the Northern Adriatic Sea.

    Science.gov (United States)

    Lo, V B; Bouma, T J; van Belzen, J; Van Colen, C; Airoldi, L

    2017-10-01

    We investigated how lateral erosion control, measured by novel photogrammetry techniques, is modified by the presence of Spartina spp. vegetation, sediment grain size, and the nutrient status of salt marshes across 230 km of the Italian Northern Adriatic coastline. Spartina spp. vegetation reduced erosion across our study sites. The effect was more pronounced in sandy soils, where erosion was reduced by 80% compared to 17% in silty soils. Erosion resistance was also enhanced by Spartina spp. root biomass. In the absence of vegetation, erosion resistance was enhanced by silt content, with mean erosion 72% lower in silty vs. sandy soils. We found no relevant relationships with nutrient status, likely due to overall high nutrient concentrations and low C:N ratios across all sites. Our results contribute to quantifying coastal protection ecosystem services provided by salt marshes in both sandy and silty sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Pulmonary effects of ultrafine and fine ammonium salts aerosols in healthy and monocrotaline-treated rats following short-term exposure

    NARCIS (Netherlands)

    Cassee, F.R.; Arts, J.H.E.; Fokkens, P.H.B.; Spoor, S.M.; Boere, A.J.F.; Bree, L. van; Dormans, J.A.M.A.

    2002-01-01

    In the present study the effects of a 3-day inhalation exposure to model compounds for ambient particulate matter were investigated: ammonium bisulfate, ammonium ferrosulfate, and ammonium nitrate, all components of the secondary aerosol fraction of ambient particulate matter (PM), and carbon black

  17. The effect of harmonized emissions on aerosol properties in global models – an AeroCom experiment

    Directory of Open Access Journals (Sweden)

    C. Textor

    2007-08-01

    Full Text Available The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA and one with unified emissions, injection heights, and particle sizes at the source (ExpB. Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols and parameterizations of aerosol microphysics (e.g., the split between deposition pathways and to a lesser extent by the spatial and temporal distributions of the (precursor emissions.

    The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences.

    These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.

  18. Salt precipitation and dissolution in the late Quaternary Dead Sea: Evidence from chemical and δ37Cl composition of pore fluids and halites

    Science.gov (United States)

    Levy, Elan J.; Yechieli, Yoseph; Gavrieli, Ittai; Lazar, Boaz; Kiro, Yael; Stein, Mordechai; Sivan, Orit

    2018-04-01

    The chemical composition and δ37Cl of pore fluids from the ICDP core drilled in the deepest floor of the terminal and hypersaline Dead Sea, and halites from the adjacent Mount Sedom salt diapir, are used to establish the dynamics of halite precipitation and dissolution during the last interglacial and glacial periods. Between ∼132 and 116 thousand years ago (ka) halites precipitated in the lake resulting in the expulsion of Na+ and Cl- from the residual solution. Over 50% of the Cl- reservoir was removed, resulting in a decrease in the Na/Cl ratio from 0.57 to 0.19. This process was accompanied by a decrease in δ37Cl values in the precipitating halites and the associated residual Cl- in the lake. The observed decrease fits a Rayleigh distillation curve with a fractionation factor of Δ(NaCl-Dead Sea solution) = +0.32‰ (±0.12) determined in the present study. This behavior implies negligible contribution of external sources of Cl- to the lake during the main peak of the last interglacial, MIS5e. Subsequently, during the last glacial (ca. 117 to 17 ka) dissolution of halite took place, the Na+ and Cl- inventory were replenished, accompanied by an increase in Na/Cl from 0.21 to 0.55 and in the δ37Cl values from -0.46‰ to -0.12‰. While the lake underwent significant dilution during that time, the decrease in salinity was somewhat suppressed by the dissolution of the halite which was mostly derived from Mount Sedom salt diapir.

  19. Sources and composition of urban aerosol particles

    Science.gov (United States)

    Vogt, M.; Johansson, C.; Mårtensson, M.; Struthers, H.; Ahlm, L.; Nilsson, D.

    2011-09-01

    From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp) from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass removed at 0.6 μm Dp. Further heating to 300 °C caused very little additional losses road traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx) and BC measured on a densely trafficked street) and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs) for non-volatile particles <0.6 μm Dp to be 2.4±1.4 mg veh-1 km-1 based on either CO2 fluxes or traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs were estimated using multiple linear regression and reveal that for non-volatile particulate matter in the 0.25 to 0.6 μm Dp range, the EFHDV is approximately twice as high as the EFLDV, the difference not being statistically significant.

  20. Aerosol Liquid Water Driven by Anthropogenic inorganic salts: Playing a key role in the winter haze formation over North China Plain

    Science.gov (United States)

    Wu, Z.; Liu, Y.; Tan, T.; Wang, Y.; Shang, D.; Xiao, Y.; Li, M.; Zeng, L.; Hu, M.

    2017-12-01

    Aerosol liquid water influences ambient particulate matter mass concentrations and aerosol optical properties, and can serve as a reactor for multiphase reactions that perturb local photochemistry1. Our observations revealed that ambient relative humidity, inorganic fraction (sulfate, ammonium, nitrate), and PM2.5 mass concentration generally simultaneously elevated during haze episodes, resulting in the abundant anthropogenic aerosol water in the atmosphere of Beijing. The enrichment of aerosol liquid water may significantly affect the particle phase, which plays a key role in determining the reactive uptake, gas-particle partitioning, and heterogeneous chemical reactivity2. A newly-built three-arm impactor was used to detect the particle rebound fraction. The observations showed the increased RH and inorganic-rich particulate matter led to an increased aerosol liquid water content, and thus a liquid phase state during haze episode during wintertime. Here, we proposed that the transition to a liquid phase state marked the beginning of the haze episode and kicked off a positive feedback loop, wherein the liquid particles readily uptake pollutants that could react to form inorganics which could then uptake more water. The strict controlling strategy of sulfur emissions in China might lead to a decreased sulfate fraction and increased nitrate fraction in PM1. As a result, due to the lower deliquescence RH of nitrate, the feedback loop proposed could start at an even lower RH in the future. Reference1 Herrmann, H., T. Schaefer, A. Tilgner, S. A. Styler, C. Weller, M. Teich, and T. Otto (2015), Tropospheric Aqueous-Phase Chemistry: Kinetics, Mechanisms, and Its Coupling to a Changing Gas Phase, Chemical Reviews, 115(10), 4259-4334.2 M. Kuwata, S. T. Martin (2012), Phase of atmospheric secondary organic material affects its reactivity, Proceedings of the National Academy of Sciences of the United States of America, 109(43):17354-17359

  1. Aerosol processing in stratiform clouds in ECHAM6-HAM

    Science.gov (United States)

    Neubauer, David; Lohmann, Ulrike; Hoose, Corinna

    2013-04-01

    Aerosol processing in stratiform clouds by uptake into cloud particles, collision-coalescence, chemical processing inside the cloud particles and release back into the atmosphere has important effects on aerosol concentration, size distribution, chemical composition and mixing state. Aerosol particles can act as cloud condensation nuclei. Cloud droplets can take up further aerosol particles by collisions. Atmospheric gases may also be transferred into the cloud droplets and undergo chemical reactions, e.g. the production of atmospheric sulphate. Aerosol particles are also processed in ice crystals. They may be taken up by homogeneous freezing of cloud droplets below -38° C or by heterogeneous freezing above -38° C. This includes immersion freezing of already immersed aerosol particles in the droplets and contact freezing of particles colliding with a droplet. Many clouds do not form precipitation and also much of the precipitation evaporates before it reaches the ground. The water soluble part of the aerosol particles concentrates in the hydrometeors and together with the insoluble part forms a single, mixed, larger particle, which is released. We have implemented aerosol processing into the current version of the general circulation model ECHAM6 (Stevens et al., 2013) coupled to the aerosol module HAM (Stier et al., 2005). ECHAM6-HAM solves prognostic equations for the cloud droplet number and ice crystal number concentrations. In the standard version of HAM, seven modes are used to describe the total aerosol. The modes are divided into soluble/mixed and insoluble modes and the number concentrations and masses of different chemical components (sulphate, black carbon, organic carbon, sea salt and mineral dust) are prognostic variables. We extended this by an explicit representation of aerosol particles in cloud droplets and ice crystals in stratiform clouds similar to Hoose et al. (2008a,b). Aerosol particles in cloud droplets are represented by 5 tracers for the

  2. Remote sensing of aerosols by synergy of caliop and modis

    Directory of Open Access Journals (Sweden)

    Kudo Rei

    2018-01-01

    Full Text Available For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obtained; the much amount of the water-soluble and light absorbing carbonaceous particles were estimated in the biomass-burning event, and the dust particles were estimated in the dust event.

  3. Remote sensing of aerosols by synergy of caliop and modis

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Higurashi, Akiko; Oikawa, Eiji

    2018-04-01

    For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products of CALIOP and MODIS. We applied the method to the biomass-burning event in Africa and the dust event in West Asia. The reasonable results were obtained; the much amount of the water-soluble and light absorbing carbonaceous particles were estimated in the biomass-burning event, and the dust particles were estimated in the dust event.

  4. Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation

    Directory of Open Access Journals (Sweden)

    N. Meskhidze

    2011-11-01

    Full Text Available Marine organic aerosol emissions have been implemented and evaluated within the National Center of Atmospheric Research (NCAR's Community Atmosphere Model (CAM5 with the Pacific Northwest National Laboratory's 7-mode Modal Aerosol Module (MAM-7. Emissions of marine primary organic aerosols (POA, phytoplankton-produced isoprene- and monoterpenes-derived secondary organic aerosols (SOA and methane sulfonate (MS are shown to affect surface concentrations of organic aerosols in remote marine regions. Global emissions of submicron marine POA is estimated to be 7.9 and 9.4 Tg yr−1, for the Gantt et al. (2011 and Vignati et al. (2010 emission parameterizations, respectively. Marine sources of SOA and particulate MS (containing both sulfur and carbon atoms contribute an additional 0.2 and 5.1 Tg yr−1, respectively. Widespread areas over productive waters of the Northern Atlantic, Northern Pacific, and the Southern Ocean show marine-source submicron organic aerosol surface concentrations of 100 ng m−3, with values up to 400 ng m−3 over biologically productive areas. Comparison of long-term surface observations of water insoluble organic matter (WIOM with POA concentrations from the two emission parameterizations shows that despite revealed discrepancies (often more than a factor of 2, both Gantt et al. (2011 and Vignati et al. (2010 formulations are able to capture the magnitude of marine organic aerosol concentrations, with the Gantt et al. (2011 parameterization attaining better seasonality. Model simulations show that the mixing state of the marine POA can impact the surface number concentration of cloud condensation nuclei (CCN. The largest increases (up to 20% in CCN (at a supersaturation (S of 0.2% number concentration are obtained over biologically productive ocean waters when marine organic aerosol is assumed to be externally mixed with sea-salt. Assuming

  5. Preliminary study on the characteristics of aerosols over the western pacific ocean

    International Nuclear Information System (INIS)

    Hu Zhaohui; Liu Pingsheng; Liu Shijie; Yao Ying; Feng Guohua

    1996-01-01

    Marine aerosol from the western Pacific were collected by two types of samplers during a cruise from Nanhai of China through the west of Philippines to the equatorial and to the north-eastern of Solomon Archipelago. Collected samples were analyzed by PIXE. The data gave aerosol characteristics over the western Pacific, including concentrations, enrichments and mass size distributions of detected elements, and possible sources of these elements were specially researched. The result indicates that Al, Si and Fe were associated with soil particles; Cl, Br, K, Ca and S showed characteristics of the sea-salt origin; and Cu, Zn, and Pb were due to pollution from long-range transport of continental aerosol. We have also made comparison with data obtained in earlier studies over other regions of the Pacific. (author)

  6. Composition and sources of winter and summertime aerosols at Ny Alesund, Spitsbergen

    International Nuclear Information System (INIS)

    Maenhaut, W.; Cornille, P.; Pacyna, J.M.

    1991-01-01

    Filter samples of < 2.5 μm aerosol were collected in (late) winter of 1983, 1984, 1986, and 1987 and in the summer of 1984, 1986, and 1987 at Ny Alesund, Spitsbergen, and analyzed for over 40 elements by a combination of INAA and PIXE. The data sets of the various sampling campaigns and the combined winter and combined summer data were examined by receptor modeling, including absolute principal component analysis (APCA), chemical mass balance (CMB) and multiple linear regression (MLR) techniques. APCA yielded four components, both for the winter and for the summer aerosol. For the winter aerosol, the components were identified as a general pollution component, crustal dust, sea-salt, and a halogen (Br,I) component. The CMB and MLR calculations were used to obtain source (source region) apportionments for the anthropogenic trace elements and for sulfate. For the summer, about 50% of the sulfate was attributed to a marine biogenic source

  7. AOD Distributions and Trends of Major Aerosol Species over a Selection of the World's Most Populated Cities Based on the 1st Version of NASA's MERRA Aerosol Reanalysis

    Science.gov (United States)

    Provencal, Simon; Kishcha, Pavel; da Silva, Arlindo M.; Elhacham, Emily; Alpert, Pinhas

    2017-01-01

    NASA recently extended the Modern-Era Retrospective Analysis for Research and Application (MERRA) with an atmospheric aerosol reanalysis which includes five particulate species: sulfate, organic matter, black carbon, mineral dust and sea salt. The MERRA Aerosol Reanalysis (MERRAero) is an innovative tool to study air quality issues around the world for its global and constant coverage and its distinction of aerosol speciation expressed in the form of aerosol optical depth (AOD). The purpose of this manuscript is to apply MERRAero to the study of urban air pollution at the global scale by analyzing the AOD over a period of 13 years (2003-2015) and over a selection of 200 of the world's most populated cities in order to assess the impacts of urbanization, industrialization, air quality regulations and regional transport which affect urban aerosol load. Environmental regulations and the recent global economic recession have helped to decrease the AOD and sulfate aerosols in most cities in North America, Europe and Japan. Rapid industrialization in China over the last two decades resulted in Chinese cities having the highest AOD values in the world. China has nevertheless recently implemented emission control measures which are showing early signs of success in many cities of Southern China where AOD has decreased substantially over the last 13 years. The AOD over South American cities, which is dominated by carbonaceous aerosols, has also decreased over the last decade due to an increase in commodity prices which slowed deforestation activities in the Amazon rainforest. At the opposite, recent urbanization and industrialization in India and Bangladesh resulted in a strong increase of AOD, sulfate and carbonaceous aerosols in most cities of these two countries. The AOD over most cities in Northern Africa and Western Asia changed little over the last decade. Emissions of natural aerosols, which cities in these two regions tend to be mostly composed of, don't tend to

  8. Worth its salt?

    Science.gov (United States)

    The idea that all underground salt deposits can serve as storage sites for toxic and nuclear waste does not always hold water—literally. According to Daniel Ronen and Brian Berkowitz of Israel's Weizmann Institute of Science and Yoseph Yechieli of the Geological Survey of Israel, some buried salt layers are in fact highly conductive of liquids, suggesting that wastes buried in their confines could easily leech into groundwater and nearby soil.When drilling three wells into a 10,000-year-old salt layer near the Dead Sea, the researchers found that groundwater had seeped into the layer and had absorbed some of its salt.

  9. Aerosol Observability and Predictability: From Research to Operations for Chemical Weather Forecasting. Lagrangian Displacement Ensembles for Aerosol Data Assimilation

    Science.gov (United States)

    da Silva, Arlindo

    2010-01-01

    A challenge common to many constituent data assimilation applications is the fact that one observes a much smaller fraction of the phase space that one wishes to estimate. For example, remotely sensed estimates of the column average concentrations are available, while one is faced with the problem of estimating 3D concentrations for initializing a prognostic model. This problem is exacerbated in the case of aerosols because the observable Aerosol Optical Depth (AOD) is not only a column integrated quantity, but it also sums over a large number of species (dust, sea-salt, carbonaceous and sulfate aerosols. An aerosol transport model when driven by high-resolution, state-of-the-art analysis of meteorological fields and realistic emissions can produce skillful forecasts even when no aerosol data is assimilated. The main task of aerosol data assimilation is to address the bias arising from inaccurate emissions, and Lagrangian misplacement of plumes induced by errors in the driving meteorological fields. As long as one decouples the meteorological and aerosol assimilation as we do here, the classic baroclinic growth of error is no longer the main order of business. We will describe an aerosol data assimilation scheme in which the analysis update step is conducted in observation space, using an adaptive maximum-likelihood scheme for estimating background errors in AOD space. This scheme includes e explicit sequential bias estimation as in Dee and da Silva. Unlikely existing aerosol data assimilation schemes we do not obtain analysis increments of the 3D concentrations by scaling the background profiles. Instead we explore the Lagrangian characteristics of the problem for generating local displacement ensembles. These high-resolution state-dependent ensembles are then used to parameterize the background errors and generate 3D aerosol increments. The algorithm has computational complexity running at a resolution of 1/4 degree, globally. We will present the result of

  10. Single-particle characterization of the High Arctic summertime aerosol

    Science.gov (United States)

    Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

    2014-01-01

    Single-particle mass spectrometric measurements were carried out in the High Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real-time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 nm to 3000 nm in diameter showed mass spectrometric patterns indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the High Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a~minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest a presence of a particle type of unknown composition

  11. Geochemical, Sulfur Isotopic Characteristics and Source Contributions of Size-Aggregated Aerosols Collected in Baring Head, New Zealand.

    Science.gov (United States)

    Li, J.; Michalski, G. M.; Davy, P.; Harvey, M.; Wilkins, B. P.; Katzman, T. L.

    2017-12-01

    Sulfate aerosols are critical to the climate, human health, and the hydrological cycle in the atmosphere, yet the sources of sulfate in aerosols are not completely understood. In this work, we evaluated the sources of sulfate in size-aggregated aerosols from the Southern Pacific Ocean and the land of New Zealand using geochemical and isotopic analyses. Aerosols were collected at Baring Head, New Zealand between 6/30/15 to 8/4/16 using two collectors, one only collects Southern Pacific Ocean derived aerosols (open-ocean collector), the other collects aerosols from both the ocean and the land (all-direction collector). Each collector is equipped with two filters to sample size-aggregated aerosols (fine aerosols: NSS-SO42-, 70%), while coarse aerosols are dominated by sea-salt sulfate. However, some NSS-SO42- was also observed in coarse aerosols collected in summer, suggesting the presence of accumulation mode NSS-SO42- aerosols, which is possibly due to high summer biogenic DMS flux. The sources of sulfur in NSS-SO42- could be further determined by their d34S values. DMS emission is likely the sole sulfur source in the open-ocean collector as it shows constant DMS-like d34S signatures (15-18‰) throughout the year. Meanwhile, the d34S of NSS-SO42- in the all-direction collector display a seasonal trend: summer time d34S values are higher and DMS-like (15-18‰), indicating DMS emission is the dominant sulfur source; winter time d34S values are lower ( 6-12‰), therefore the sulfur is likely sourced from both DMS emission and terrestrial S input with low d34S values, such as volcanic activities, fossil fuel and wood burning.

  12. Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

    Directory of Open Access Journals (Sweden)

    B. Croft

    2012-11-01

    scheme since nearly all entrained accumulation and coarse mode aerosols are assumed to be cloud-droplet borne or ice-crystal borne, and evaporation due to the Bergeron-Findeisen process is neglected.

    The simulated convective wet scavenging of entrained accumulation and coarse mode aerosols has feedbacks on new particle formation and the number of Aitken mode aerosols, which control stratiform and convective cloud droplet number concentrations and yield precipitation changes in the ECHAM5-HAM model. However, the geographic distribution of aerosol annual mean convective wet deposition change in the model is driven by changes to the assumptions regarding the scavenging of aerosols entrained above cloud bases rather than by precipitation changes, except for sea salt deposition in the tropics. Uncertainty in the seasonal, regional cycles of AOD due to assumptions about entrained aerosol wet scavenging is similar in magnitude to the estimated error in the AOD retrievals.

    The uncertainty in aerosol concentrations, burdens, and AOD attributed to different assumptions for the wet scavenging of aerosols entrained above convective cloud bases in a global model motivates the ongoing need to better understand and model the activation and impaction processes that aerosols undergo after entrainment into convective updrafts.

  13. Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

    Science.gov (United States)

    Croft, B.; Pierce, J. R.; Martin, R. V.; Hoose, C.; Lohmann, U.

    2012-11-01

    entrained accumulation and coarse mode aerosols are assumed to be cloud-droplet borne or ice-crystal borne, and evaporation due to the Bergeron-Findeisen process is neglected. The simulated convective wet scavenging of entrained accumulation and coarse mode aerosols has feedbacks on new particle formation and the number of Aitken mode aerosols, which control stratiform and convective cloud droplet number concentrations and yield precipitation changes in the ECHAM5-HAM model. However, the geographic distribution of aerosol annual mean convective wet deposition change in the model is driven by changes to the assumptions regarding the scavenging of aerosols entrained above cloud bases rather than by precipitation changes, except for sea salt deposition in the tropics. Uncertainty in the seasonal, regional cycles of AOD due to assumptions about entrained aerosol wet scavenging is similar in magnitude to the estimated error in the AOD retrievals. The uncertainty in aerosol concentrations, burdens, and AOD attributed to different assumptions for the wet scavenging of aerosols entrained above convective cloud bases in a global model motivates the ongoing need to better understand and model the activation and impaction processes that aerosols undergo after entrainment into convective updrafts.

  14. Decadal trends in aerosol chemical composition at Barrow, Alaska: 1976–2008

    Directory of Open Access Journals (Sweden)

    G. E. Shaw

    2009-11-01

    Full Text Available Aerosol measurements at Barrow, Alaska during the past 30 years have identified the long range transport of pollution associated with Arctic Haze as well as ocean-derived aerosols of more local origin. Here, we focus on measurements of aerosol chemical composition to assess (1 trends in Arctic Haze aerosol and implications for source regions, (2 the interaction between pollution-derived and ocean-derived aerosols and the resulting impacts on the chemistry of the Arctic boundary layer, and (3 the response of aerosols to a changing climate. Aerosol chemical composition measured at Barrow, AK during the Arctic haze season is compared for the years 1976–1977 and 1997–2008. Based on these two data sets, concentrations of non-sea salt (nss sulfate (SO4= and non-crustal (nc vanadium (V have decreased by about 60% over this 30 year period. Consistency in the ratios of nss SO4=/ncV and nc manganese (Mn/ncV between the two data sets indicates that, although emissions have decreased in the source regions, the source regions have remained the same over this time period. The measurements from 1997–2008 indicate that, during the haze season, the nss SO4= aerosol at Barrow is becoming less neutralized by ammonium (NH4+ yielding an increasing sea salt aerosol chloride (Cl deficit. The expected consequence is an increase in the release of Cl atoms to the atmosphere and a change in the lifetime of volatile organic compounds (VOCs including methane. In addition, summertime concentrations of biogenically-derived methanesulfonate (MSA and nss SO4= are increasing at a rate of 12 and 8% per year, respectively. Further research is required to assess the environmental factors behind the increasing concentrations of biogenic aerosol.

  15. Aerosol size-dependent below-cloud scavenging by rain and snow in the ECHAM5-HAM

    Directory of Open Access Journals (Sweden)

    R. Posselt

    2009-07-01

    Full Text Available Wet deposition processes are highly efficient in the removal of aerosols from the atmosphere, and thus strongly influence global aerosol concentrations, and clouds, and their respective radiative forcings. In this study, physically detailed size-dependent below-cloud scavenging parameterizations for rain and snow are implemented in the ECHAM5-HAM global aerosol-climate model. Previously, below-cloud scavenging by rain in the ECHAM5-HAM was simply a function of the aerosol mode, and then scaled by the rainfall rate. The below-cloud scavenging by snow was a function of the snowfall rate alone. The global mean aerosol optical depth, and sea salt burden are sensitive to the below-cloud scavenging coefficients, with reductions near to 15% when the more vigorous size-dependent below-cloud scavenging by rain and snow is implemented. The inclusion of a prognostic rain scheme significantly reduces the fractional importance of below-cloud scavenging since there is higher evaporation in the lower troposphere, increasing the global mean sea salt burden by almost 15%. Thermophoretic effects are shown to produce increases in the global and annual mean number removal of Aitken size particles of near to 10%, but very small increases (near 1% in the global mean below-cloud mass scavenging of carbonaceous and sulfate aerosols. Changes in the assumptions about the below-cloud scavenging by rain of particles with radius smaller than 10 nm do not cause any significant changes to the global and annual mean aerosol mass or number burdens, despite a change in the below-cloud number removal rate for nucleation mode particles by near to five-fold. Annual and zonal mean nucleation mode number concentrations are enhanced by up to 30% in the lower troposphere with the more vigourous size-dependent below-cloud scavenging. Closer agreement with different observations is found when the more physically detailed below-cloud scavenging parameterization is employed in the ECHAM5

  16. Transport of dust and anthropogenic aerosols across Alexandria, Egypt

    Energy Technology Data Exchange (ETDEWEB)

    El-Askary, H. [Chapman Univ., Orange, CA (United States). Dept. of Physics Computational Science and Engineering; Chapman Univ., Orange, CA (United States). Center of Excellence in Earth Observing; Alexandria Univ. (Egypt). Dept. of Environmental Sciences; National Authority for Remote Sensing and Space Science (NARSS), Cairo (Egypt); Farouk, R. [Alexandria Univ. (Egypt). Dept. of Environmental Sciences; Ichoku, C. [NASA Goddard Space Flight Center, Greenbelt, MD (United States). Climate and Radiation Branch; Kafatos, M. [Chapman Univ., Orange, CA (United States). Dept. of Physics Computational Science and Engineering; Chapman Univ., Orange, CA (United States). Center of Excellence in Earth Observing

    2009-07-01

    The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, and the Nile Delta in Egypt. We have carried out measurements acquired with a ground- based portable sun photometer (Microtops II) and the satellite-borne TERRA/Moderate Resolution Imaging Spectroradiometer (MODIS) sensor during the periods of October 1999-August 2001 and July 2002-September 2003. These measurements show a seasonal variability in aerosol optical depth (AOD) following these flow patterns. Maximum aerosol loadings accompanied by total precipitable water vapor (W) enhancements are observed during the spring and summer seasons. Pronounced changes have been observed in the Aangstroem exponent ({alpha}) derived from ground-based measurements over Alexandria (31.14 N, 29.59 E) during both dust and pollution periods. We have followed up the observations with a 3-day back-trajectories model to trace the probable sources and pathways of the air masses causing the observed aerosol loadings. We have also used other NASA model outputs to estimate the sea salt, dust, sulfates and black carbon AOD spatial distributions during different seasons. Our results reveal the probable source regions of these aerosol types, showing agreement with the trajectory and Aangstroem exponent analysis results. It is confirmed that Alexandria is subjected to different atmospheric conditions involving dust, pollution, mixed aerosols and clean sky. (orig.)

  17. Gradient flux measurements of sea-air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

    Science.gov (United States)

    Smith, Murray J.; Walker, Carolyn F.; Bell, Thomas G.; Harvey, Mike J.; Saltzman, Eric S.; Law, Cliff S.

    2018-04-01

    Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in February-March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L-1. Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC) technique using atmospheric pressure chemical ionization-mass spectrometry (API-CIMS) and the gradient flux (GF) technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean-Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r2 = 0.89). A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG model.

  18. A natural analogue for near-field behaviour in a high level radioactive waste repository in salt: the Salton Sea geothermal field, California, USA

    International Nuclear Information System (INIS)

    Elders, W.A.

    1987-01-01

    In the Salton Sea Geothermal Field (SSGF), in the sediments of the delta of the Colorado River, we are developing a three-dimensional picture of active water/rock reactions at temperatures of 0 C and salinities of 7 to 25 weight percent to produce quantitative data on mineral stabilities and mobilities of naturally-occurring radio-nuclides. The aim is to produce data to validate geochemical computer codes being developed to assess the performance of a Commercial High-Level Waste (CHLW) repository in salt. Among the findings to date are: (1) greenschist facies metamorphism is occurring; (2) brine compositions are fairly similar to those expected in candidate salt repository sites; (3) U and Th concentrations in the rocks are typical for sedimentary rocks; (4) the brines are enriched in Na, Mn, Zn, Sr, Ra Po and strongly depleted in U and Th relative to the rocks; (5) significant radioactive disequilibria exist in brines and solid phases of the SSGF. The disequilibria in the actinide series allow estimation of the rates of brine-rock interaction and understanding of hydrologic processes and radionuclide behaviour. Work is continuing emphasizing the reactions of authigenic clay minerals, epidotes, feldspars, chlorites and sulphates. So far, adapting geochemical codes to the necessary combination of high salinity and high temperature has lagged behind the natural analogue study of the SSGF so that validation is still in progress. In the future our data can be also used in validating performance assessment codes which couple geochemistry and transport processes, and in design of waste packages and back fill compositions. (author)

  19. Effects of Ocean Ecosystem on Marine Aerosol-Cloud Interaction

    Directory of Open Access Journals (Sweden)

    Nicholas Meskhidze

    2010-01-01

    Full Text Available Using satellite data for the surface ocean, aerosol optical depth (AOD, and cloud microphysical parameters, we show that statistically significant positive correlations exist between ocean ecosystem productivity, the abundance of submicron aerosols, and cloud microphysical properties over different parts of the remote oceans. The correlation coefficient for remotely sensed surface chlorophyll a concentration ([Chl-a] and liquid cloud effective radii over productive areas of the oceans varies between −0.2 and −0.6. Special attention is given to identifying (and addressing problems from correlation analysis used in the previous studies that can lead to erroneous conclusions. A new approach (using the difference between retrieved AOD and predicted sea salt aerosol optical depth, AODdiff is developed to explore causal links between ocean physical and biological systems and the abundance of cloud condensation nuclei (CCN in the remote marine atmosphere. We have found that over multiple time periods, 550 nm AODdiff (sensitive to accumulation mode aerosol, which is the prime contributor to CCN correlates well with [Chl-a] over the productive waters of the Southern Ocean. Since [Chl-a] can be used as a proxy of ocean biological productivity, our analysis demonstrates the role of ocean ecology in contributing CCN, thus shaping the microphysical properties of low-level marine clouds.

  20. Single particle composition measurements of artificial Calcium Carbonate aerosols

    Science.gov (United States)

    Zorn, S. R.; Mentel, T. F.; Schwinger, T.; Croteau, P. L.; Jayne, J.; Worsnop, D. R.; Trimborn, A.

    2012-12-01

    Mineral dust, with an estimated total source from natural and anthropogenic emissions of up to 2800 Tg/yr, is one of the two largest contributors to total aerosol mass, with only Sea salt having a similar source strength (up to 2600 Tg/yr). The composition of dust particles varies strongly depending on the production process and, most importantly, the source location. Therefore, the composition of single dust particles can be used both to trace source regions of air masses as well as to identify chemical aging processes. Here we present results of laboratory studies on generating artificial calcium carbonate (CaCO3) particles, a model compound for carbonaceous mineral dust particles. Particles were generated by atomizing an aqueous hydrogen carbonate solution. Water was removed using a silica diffusion dryer., then the particles were processed in an oven at temperatures up to 900°C, converting the hydrogen carbonate to its anhydrous form. The resulting aerosol was analyzed using an on-line single particle laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The results confirm the conversion to calcium carbonate, and validate that the produced particles indeed can be used as a model compound for carbonaceous dust aerosols.

  1. Chemical properties and morphology of Marine Aerosol in the Mediterranean atmosphere: a mesocosm study

    Science.gov (United States)

    D'Anna, Barbara; Sellegri, Karine; Charrière, Bruno; Sempéré, Richard; Mas, Sébastien; Marchand, Nicolas; George, Christian; Même, Aurèlie; R'mili, Badr; Delmont, Anne; Schwier, Allison; Rose, Clémence; Colomb, Aurèlie; Pey, Jorge; Langley Dewitt, Helen

    2014-05-01

    The Mediterranean Sea is a special marine environment characterized by low biological activity and high anthropogenic pressure. It is often difficult to discriminate the contribution of Primary Sea Salt Aerosol formed at the sea surface from background level of the aerosol. An alternative tool to study the sea-air exchanges in a controlled environment is provided by the mesocosms, which represent an important link between field studies and laboratory experiments. The sea-air transfer of particles and gases was investigated in relation to water chemical composition and biological activity during a mesocosm experiment within the SAM project (Sources of marine Aerosol in the Mediterranean) at the Oceanographic and Marine Station STARESO in Western Corsica (May 2013). Three 2 m mesocosms were filled with screened (sensors and received different treatments: one was left unchanged as control and two were enriched by addition of nitrates and phosphates respecting Redfield ratio (N:P = 16). The evolution of the three systems was followed for 20 days. The set of sensors in each mesocosm was allowed to monitor, at high frequency (every 10 min), the water temperature, conductivity, pH, incident light, fluorescence of chlorophyll a and dissolved oxygen concentration. The mesocosm seawaters were daily sampled for chemical (colored dissolved organic matter, particulate matter and related polar compounds, transparent polysaccharides and nutrients concentration) and biological (chlorophyll a, virus, phytoplankton and zooplankton) analyses. Both dissolved and gaseous VOCs were also analyzed. In addition, few liters of seawater from each mesocosm were daily and immediately collected and transferred to a bubble-bursting apparatus to simulate nascent sea spray aerosol. On-line chemical analysis of the sub-micrometer fraction was performed by a TOF-AMS (Aerodyne). Off-line analysis included TEM-EDX for morphology and size distribution studies and a hybrid quadrupole-orbitrap mass

  2. Aerosol Meteorology of the Maritime Continent for the 2012 7SEAS Southwest Monsoon Intensive Study - Part 1: Regional-scale Phenomena

    Science.gov (United States)

    Reid, Jeffrey S.; Xian, Peng; Holben, Brent N.; Hyer, Edward J.; Reid, Elizabeth A.; Salinas, Santo V.; Zhang, Jianglong; Campbell, James R.; Chew, Boon Ning; Holz, Robert E.; hide

    2016-01-01

    The largest 7 Southeast Asian Studies (7SEAS) operation period within the Maritime Continent (MC) occurred in the August-September 2012 biomass burning season. Included was an enhanced deployment of Aerosol Robotic Network (AERONET) sun photometers, multiple lidars, and field measurements to observe transported smoke and pollution as it left the MC and entered the southwest monsoon trough. Here we describe the nature of the overall 2012 southwest monsoon (SWM) and biomass burning season to give context to the 2012 deployment. The MC in 2012 was in a slightly warm El Nino Southern Oscillation (ENSO) phase and with spatially typical burning activity. However, overall fire counts for 2012 were 10 lower than the Reid et al. (2012) baseline, with regions of significant departures from this norm, ranging from southern Sumatra (+30) to southern Kalimantan (42). Fire activity and monsoonal flows for the dominant burning regions were modulated by a series of intraseasonal oscillation events (e.g., Madden-Julian Oscillation, or MJO, and boreal summer intraseasonal oscillation, or BSISO). As is typical, fire activity systematically progressed eastward over time, starting with central Sumatran fire activity in June related to a moderately strong MJO event which brought drier air from the Indian Ocean aloft and enhanced monsoonal flow. Further burning in Sumatra and Kalimantan Borneo occurred in a series of significant events from early August to a peak in the first week of October, ending when the monsoon started to migrate back to its wintertime northeastern flow conditions in mid-October. Significant monsoonal enhancements and flow reversals collinear with tropical cyclone (TC) activity and easterly waves were also observed. Islands of the eastern MC, including Sulawesi, Java, and Timor, showed less sensitivity to monsoonal variation, with slowly increasing fire activity that also peaked in early October but lingered into November. Interestingly, even though fire counts were

  3. Sources and Transport of Aerosol above the Boundary Layer over the Mediterranean Basin

    Science.gov (United States)

    Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Veronique; Claeys, Marine; Sciare, Jean; Mallet, Marc; Dulac, François; Mihalopoulos, Nikos

    2015-04-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation

  4. Long-range Transport of Aerosol at a Mountain Site in the Western Mediterranean Basin

    Science.gov (United States)

    Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Véronique; Claeys, Marine; Sciare, Jean; Dulac, François

    2016-04-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation

  5. Seasonality of major aerosol species and their transformations in Cairo mega-city

    International Nuclear Information System (INIS)

    Favez, O.; Cachier, H.; Sciare, J.; Alfaro, S.C.; El-Araby, T.M.; Harhash, M.A.; Abdelwahab, M.M.

    2008-01-01

    Bulk aerosols sampled oil a weekly basis at two Cairo (Egypt) urban sites from January 2003 to May 2006 were analysed for their chemical composition of major aerosol species (elemental carbon, water soluble/insoluble organic carbon, nitrate, sulphate, ammonium, chloride, sodium and calcium). Data subsequently obtained constitute one of the longest and more detailed dataset related to Cairo aerosols, and offer the opportunity to investigate seasonal trends. Dust aerosols (derived from calcium measurements) displayed maximum concentrations in spring and winter, due to frequent dust storms, but also high background concentration levels (∼ 50 μgm -3 ), all year long. Within these particles, about 40% oil average of Ca 2+ was found to be associated SO 4 2- , NO 3 - and/or Cl - , pointing out 'dust anthropization' processes and their subsequent climatic impact oil a regional scale. Seasonal variations of non-dust aerosols, equally distributed between carbonaceous aerosols and ions, were also observed, with concentrations of the order of 100 μgm -3 in autumn and winter, and of 60 μgm -3 in spring and summer. High concentration levels of non-sea-salt chloride (up to 15 μg m -3 on a monthly basis), likely of industrial origin, were observed in autumn and winter. During the autumn 'Black Cloud' event, biomass burning aerosols originating front rice straw burning in the Nile Delta have shown to account for 12%, 35%, and 50% of Cairo EC, WIOC and WSOC mass concentrations, respectively. Finally, relatively low WSOC/OC ratios (similar to 1/3) were obtained all the year long, calling for more investigation oil the water-solubility of organic aerosols originating from the burning of agricultural waste, and oil that of secondary organic aerosols formed in dry urban atmospheres. (authors)

  6. Effect of phytoplackton-derived organic matter on the behavior of marine aerosols

    Science.gov (United States)

    Fuentes, E.; Coe, H.; McFiggans, G.; Green, D.

    2009-04-01

    The presence of significant concentrations of organic material in marine aerosols has been appreciated for several decades; however, only recently has significant progress been made towards demonstrating that this organic content is biogenically formed. Biogenic organics of placktonic life origin are incorporated in marine aerosol composition as a result of bubble bursting/breaking waves mechanisms that occur at the ocean surface. The presence of organic surfactants in the marine aerosol composition might have a significant impact on the properties of the generated aerosols by affecting the particles surface tension and solution balance properties. Nevertheless, it remains uncertain the role of such organics on the physical-chemical behavior of marine aerosols. In this work an experimental study was performed in order to determine the influence of biogenic marine organic compounds on the size distribution, hygroscopicity and cloud-nucleating properties of marine aerosols. For the experimental study a laboratory water recirculation system (bubble tank), designed for the simulation of bubble-burst aerosol formation, was used as marine aerosol generator. The bubble spectra produced by such system was characterized by means of an optical bubble measuring device (BMS) and it was found to be consistent with oceanic bubble spectra properties. Seawater proxy solutions were prepared from laboratory biologically-synthesized exudates produced by oceanic representative algal species and introduced in the tank for the generation of marine aerosol by bubble bursting. Two experimental methods were employed for seawater proxies preparation: the formation of surface monolayers from the biogenic surfactants extracted by a solid phase extraction technique (monolayer method) and the mixing of the exudates in the sea salt water bulk (bulk mixing method). Particle size distribution, hygroscopicity and cloud condensation nuclei experiments for different monolayers, and exudate mixtures

  7. Microphysical and optical properties of aerosol particles in urban zone during ESCOMPTE

    Science.gov (United States)

    Mallet, M.; Roger, J. C.; Despiau, S.; Dubovik, O.; Putaud, J. P.

    2003-10-01

    Microphysical and optical properties of the main aerosol species on a peri-urban site have been investigated during the ESCOMPTE experiment. Ammonium sulfate (AS), nitrate (N), black carbon (BC), particulate organic matter (POM), sea salt (SS) and mineral aerosol (D) size distributions have been used, associated with their refractive index, to compute, from the Mie theory, the key radiative aerosol properties as the extinction coefficient Kext, the mass extinction efficiencies σext, the single scattering albedo ω0 and the asymmetry parameter g at the wavelength of 550 nm. Optical computations show that 90% of the light extinction is due to anthropogenic aerosol and only 10% is due to natural aerosol (SS and D). 44±6% of the extinction is due to (AS) and 40±6% to carbonaceous particles (20±4% to BC and 21±4% to POM). Nitrate aerosol has a weak contribution of 5±2%. Computations of the mass extinction efficiencies σext, single scattering albedo ω0 and asymmetry parameter g indicate that the optical properties of the anthropogenic aerosol are often quite different from those yet published and generally used in global models. For example, the (AS) mean specific mass extinction presents a large difference with the value classically adopted at low relative humidity ( h<60%) (2.6±0.5 instead of 6 m 2 g -1 at 550 nm). The optical properties of the total aerosol layer, including all the aerosol species, indicate a mean observed single-scattering albedo ω0=0.85±0.05, leading to an important absorption of the solar radiation and an asymmetry parameter g=0.59±0.05 which are in a reasonably good agreements with the AERONET retrieval of ω0 (=0.86±0.05) and g (=0.64±0.05) at this wavelength.

  8. Response of northern hemisphere environmental and atmospheric conditions to climate changes using Greenland aerosol records from the Eemian to the Holocene

    Science.gov (United States)

    Fischer, H.

    2017-12-01

    The Northern Hemisphere experienced dramatic climate changes over the last glacial cycle, including vast ice sheet expansion and frequent abrupt climate events. Moreover, high northern latitudes during the last interglacial (Eemian) were warmer than today and may provide guidance for future climate change scenarios. However, little evidence exists regarding the environmental alterations connected to these climate changes. Using aerosol concentration records in decadal resolution from the North Greenland Eemian Ice Drilling (NEEM) over the last 128,000 years we extract quantitative information on environmental changes, including the first comparison of northern hemisphere environmental conditions between the warmer than present Eemian and the early Holocene. Separating source changes from transport effects, we find that changes in the ice concentration greatly overestimate the changes in atmospheric concentrations in the aerosol source region, the latter mirroring changes in aerosol emissions. Glacial times were characterized by a strong reduction in terrestrial biogenic emissions (only 10-20% of the early Holocene value) reflecting the net loss of vegetated area in mid to high latitudes, while rapid climate changes during the glacial had essentially no effect on terrestrial biogenic aerosol emissions. An increase in terrestrial dust emissions of approximately a factor of eight during peak glacial and cold stadial intervals indicates higher aridity and dust storm activity in Asian deserts. Glacial sea salt aerosol emissions increased only moderately (by approximately 50%), likely due to sea ice expansion, while marked stadial/interstadial variations in sea salt concentrations in the ice reflect mainly changes in wet deposition en route. Eemian ice contains lower aerosol concentrations than ice from the early Holocene, due to shortened atmospheric residence time during the warmer Eemian, suggesting that generally 2°C warmer climate in high northern latitudes did not

  9. Algorithms to retrieve optical properties of three component aerosols from two-wavelength backscatter and one-wavelength polarization lidar measurements considering nonsphericity of dust

    International Nuclear Information System (INIS)

    Nishizawa, Tomoaki; Sugimoto, Nobuo; Matsui, Ichiro; Shimizu, Atsushi; Okamoto, Hajime

    2011-01-01

    We developed backward and forward types of algorithms for estimating the vertical profiles of extinction coefficients at 532 nm for three component aerosols (water-soluble, dust, and sea salt) using three-channel Mie-scattering lidar data of the backscatter (β) at 532 and 1064 nm and the depolarization ratio (δ) at 532 nm. While the water-soluble and sea-salt particles were reasonably assumed to be spherical, the dust particles were treated as randomly oriented spheroids to account for their nonsphericity. The introduction of spheroid models enabled us to more effectively use the three-channel data (i.e., 2β+1δ data) and to reduce the uncertainties caused by the assumption of spherical dust particles in our previously developed algorithms. We also performed an extensive sensitivity study to estimate retrieval errors, which showed that the errors in the extinction coefficient for each aerosol component were smaller than 30% (60%) for the backward (forward) algorithm when the measurement errors were ±5%. We demonstrated the ability of the algorithms to partition aerosol layers consisting of three aerosol components by applying them to shipborne lidar data. Comparisons with sky radiometer measurements revealed that the retrieved optical thickness and angstrom exponent of aerosols using the algorithms developed in this paper agreed well with the sky radiometer measurements (within 6%).

  10. Latitudinal and longitudinal variation in aerosol characteristics from ...

    Indian Academy of Sciences (India)

    The physical and chemical properties of aerosols are strong ... Keywords. Aerosol optical characteristics; latitudinal and longitudinal variations; Bay of Bengal; Arabian Sea; pre- ...... of global sources of atmospheric soil dust identified with the ...

  11. Preliminary petrological and geochemical results from the Salton Sea Geothermal Field, California: A near-field natural analog of a radioactive waste repository in salt: Topical report No. 2

    International Nuclear Information System (INIS)

    Elders, W.A.; Cohen, L.H.; Williams, A.E.; Neville, S.; Collier, P.; Oakes, C.

    1986-03-01

    High concentrations of radionuclides and high temperatures are not naturally encountered in salt beds. For this reason, the Salton Sea Geothermal Field (SSGF) may be the best available geologic analog of some of the processes expected to occur in high level nuclear waste repositories in salt. Subsurface temperatures and brine concentrations in the SSGF span most of the temperature range and fluid inclusion brine range expected in a salt repository, and the clay-rich sedimentary rocks are similar to those which host bedded or domal salts. As many of the chemical processes observed in the SSGF are similar to those expected to occur in or near a salt repository, data derived from it can be used in the validation of geochemical models of the near-field of a repository in salt. This report describes preliminary data on petrology and geochemistry, emphasizing the distribution of rare earth elements and U and Th, of cores and cuttings from several deep wells chosen to span a range of temperature gradients and salinities. Subsurface temperature logs have been augmented by fluid inclusion studies, to reveal the effects of brines of varying temperature and salinity. The presence of brines with different oxygen isotopic signatures also indicate lack of mixing. Whole rock major, minor and trace element analyses and data on brine compositions are being used to study chemical migration in these sediments. 65 refs., 20 figs., 3 tabs

  12. Continuous 25-yr aerosol records at coastal Antarctica - I: inter-annual variability of ionic compounds and links to climate indices

    Energy Technology Data Exchange (ETDEWEB)

    Weller, Rolf; Koenig-Langlo, Gert (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)), e-mail: Rolf.Weller@awi.de; Wagenbach, Dietmar; Elsaesser, Christoph (Institut fur Umweltphysik, Univ. of Heidelberg, Heidelberg (Germany)); Legrand, Michel (Laboratoire de Glaciologie et Geophysique de l' Environnement du Centre National de la Recherche Scientifique, St Martin d' Heres (France)); Tian-Kunze, Xiangshan (Institut fur Meereskunde, Univ. of Hamburg, Hamburg (Germany))

    2011-11-15

    The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non-sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (-3.6 +- 2.5% per year between 1983 and 1993 and +4.0 +- 3.2% per year from 1993-2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses revealed that relations to sea ice extent and various circulation indices are weak at best or not significant. In particular, no consistent link between sea ice extent and sea salt loadings was evident suggesting only a rather local relevance of the NM sea salt record. Nevertheless, a higher Southern Annular Mode index tended to entail a lower biogenic sulphur signal. In examining the spatial uniformity of the NM findings we contrasted them to respective 17 yr records from the coastal Dumont d'Urville Station. We found similar long-term trends for nitrate, indicating an Antarctic-wide but not identifiable atmospheric signal, although any significant impact of solar activity or pollution could be ruled out. No inter-site variability on the multiannual scale was evident for the other ionic compounds

  13. Aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing in Guangzhou during the 2006 Pearl River Delta campaign.

    Science.gov (United States)

    Jung, Jinsang; Lee, Hanlim; Kim, Young J; Liu, Xingang; Zhang, Yuanhang; Gu, Jianwei; Fan, Shaojia

    2009-08-01

    Optical and chemical aerosol measurements were obtained from 2 to 31 July 2006 at an urban site in the metropolitan area of Guangzhou (China) as part of the Program of Regional Integrated Experiment of Air Quality over Pearl River Delta (PRIDE-PRD2006) to investigate aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing. During the PRIDE-PRD2006 campaign, the average contributions of ammonium sulfate, organic mass by carbon (OMC), elemental carbon (EC), and sea salt (SS) to total PM(2.5) mass were measured to be 36.5%, 5.7%, 27.1%, 7.8%, and 3.7%, respectively. Compared with the clean marine period, (NH(4))(2)SO(4), NH(4)NO(3), and OMC were all greatly enhanced (by up to 430%) during local haze periods via the accumulation of a secondary aerosol component. The OMC dominance increased when high levels of biomass burning influenced the measurement site while (NH(4))(2)SO(4) and OMC did when both biomass burning and industrial emissions influenced it. The effect of aerosol water content on the total light-extinction coefficient was estimated to be 34.2%, of which 25.8% was due to aerosol water in (NH(4))(2)SO(4), 5.1% that in NH(4)NO(3), and 3.3% that in SS. The average mass-scattering efficiency (MSE) of PM(10) particles was determined to be 2.2+/-0.6 and 4.6+/-1.7m(2)g(-1) under dry (RHwater content, but MSE and SSA are also highly sensitive. It can be concluded that sulfate and carbonaceous aerosol, as well as aerosol water content, play important roles in the processes that determine visibility impairment and radiative forcing in the ambient atmosphere of the Guangzhou urban area.

  14. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  15. Nitrogen speciation in various types of aerosols in spring over the northwestern Pacific Ocean

    Directory of Open Access Journals (Sweden)

    L. Luo

    2016-01-01

    Full Text Available The cumulative atmospheric nitrogen deposition has been found to profoundly impact the nutrient stoichiometry of the eastern China seas (ECSs: the Yellow Sea and East China Sea and the northwestern Pacific Ocean (NWPO. In spite of the potential significance of dry deposition in those regions, shipboard observations of atmospheric aerosols remain insufficient, particularly regarding the compositions of water-soluble nitrogen species (nitrate, ammonium and water-soluble organic nitrogen – WSON. We conducted a cruise covering the ECSs and the NWPO during the spring of 2014 and observed three types of atmospheric aerosols. Aluminum content, air mass backward trajectories, weather conditions, and ion stoichiometry allowed us to discern dust aerosol patches and sea-fog-modified aerosols (widespread over the ECSs from background aerosols (open ocean. Among the three types, sea-fog-modified aerosols contained the highest concentrations of nitrate (536 ± 300 nmol N m−3, ammonium (442 ± 194 nmol N m−3 and WSON (147 ± 171 nmol N m−3; furthermore, ammonium and nitrate together occupied  ∼  65 % of the molar fraction of total ions. The dust aerosols also contained significant amounts of nitrate (100 ± 23 nmol N m−3 and ammonium (138 ± 24 nmol N m−3 which were obviously larger than those in the background aerosols (26 ± 32 for nitrate and 54 ± 45 nmol N m−3 for ammonium, yet this was not the case for WSON. It appeared that dust aerosols had less of a chance to come in contact with WSON during their transport. In the open ocean, we found that sea salt (e.g., Na+, Cl−, Mg2+, as well as WSON, correlated positively with wind speed. Apparently, marine dissolved organic nitrogen (DON was emitted from breaking waves. Regardless of the variable wind speeds from 0.8 to as high as 18 m s−1, nitrate and ammonium, by contrast, remained in narrow ranges, implying that

  16. Remote-sensing-based analysis of landscape change in the desiccated seabed of the Aral Sea--a potential tool for assessing the hazard degree of dust and salt storms.

    Science.gov (United States)

    Löw, F; Navratil, P; Kotte, K; Schöler, H F; Bubenzer, O

    2013-10-01

    With the recession of the Aral Sea in Central Asia, once the world's fourth largest lake, a huge new saline desert emerged which is nowadays called the Aralkum. Saline soils in the Aralkum are a major source for dust and salt storms in the region. The aim of this study was to analyze the spatio-temporal land cover change dynamics in the Aralkum and discuss potential implications for the recent and future dust and salt storm activity in the region. MODIS satellite time series were classified from 2000-2008 and change of land cover was quantified. The Aral Sea desiccation accelerated between 2004 and 2008. The area of sandy surfaces and salt soils, which bear the greatest dust and salt storm generation potential increased by more than 36 %. In parts of the Aralkum desalinization of soils was found to take place within 4-8 years. The implication of the ongoing regression of the Aral Sea is that the expansion of saline surfaces will continue. Knowing the spatio-temporal dynamics of both the location and the surface characteristics of the source areas for dust and salt storms allows drawing conclusions about the potential hazard degree of the dust load. The remote-sensing-based land cover assessment presented in this study could be coupled with existing knowledge on the location of source areas for an early estimation of trends in shifting dust composition. Opportunities, limits, and requirements of satellite-based land cover classification and change detection in the Aralkum are discussed.

  17. Assessing the impact of aerosol-atmosphere interactions in convection-permitting regional climate simulations: the Rolf medicane in 2011

    Science.gov (United States)

    José Gómez-Navarro, Juan; María López-Romero, José; Palacios-Peña, Laura; Montávez, Juan Pedro; Jiménez-Guerrero, Pedro

    2017-04-01

    A critical challenge for assessing regional climate change projections relies on improving the estimate of atmospheric aerosol impact on clouds and reducing the uncertainty associated with the use of parameterizations. In this sense, the horizontal grid spacing implemented in state-of-the-art regional climate simulations is typically 10-25 kilometers, meaning that very important processes such as convective precipitation are smaller than a grid box, and therefore need to be parameterized. This causes large uncertainties, as closure assumptions and a number of parameters have to be established by model tuning. Convection is a physical process that may be strongly conditioned by atmospheric aerosols, although the solution of aerosol-cloud interactions in warm convective clouds remains nowadays a very important scientific challenge, rendering parametrization of these complex processes an important bottleneck that is responsible from a great part of the uncertainty in current climate change projections. Therefore, the explicit simulation of convective processes might improve the quality and reliability of the simulations of the aerosol-cloud interactions in a wide range of atmospheric phenomena. Particularly over the Mediterranean, the role of aerosol particles is very important, being this a crossroad that fuels the mixing of particles from different sources (sea-salt, biomass burning, anthropogenic, Saharan dust, etc). Still, the role of aerosols in extreme events in this area such as medicanes has been barely addressed. This work aims at assessing the role of aerosol-atmosphere interaction in medicanes with the help of the regional chemistry/climate on-line coupled model WRF-CHEM run at a convection-permitting resolution. The analysis is exemplary based on the "Rolf" medicane (6-8 November 2011). Using this case study as reference, four sets of simulations are run with two spatial resolutions: one at a convection-permitting configuration of 4 km, and other at the

  18. Enviro-HIRLAM/ HARMONIE Studies in ECMWF HPC EnviroAerosols Project

    Science.gov (United States)

    Hansen Sass, Bent; Mahura, Alexander; Nuterman, Roman; Baklanov, Alexander; Palamarchuk, Julia; Ivanov, Serguei; Pagh Nielsen, Kristian; Penenko, Alexey; Edvardsson, Nellie; Stysiak, Aleksander Andrzej; Bostanbekov, Kairat; Amstrup, Bjarne; Yang, Xiaohua; Ruban, Igor; Bergen Jensen, Marina; Penenko, Vladimir; Nurseitov, Daniyar; Zakarin, Edige

    2017-04-01

    convection permitting weather model" & "Meteorological and chemical urban scale modelling for Shanghai metropolitan area" with focus on aerosol effects and influence of urban areas in China at regional-subregional-urban scales. At fourth, study on "Direct variational data assimilation algorithm for atmospheric chemistry data with transport and transformation model" with focus on testing chemical data assimilation algorithm of in situ concentration measurements on real data scenario. At firth, study on "Aerosol influence on High Resolution NWP HARMONIE Operational Forecasts" with focus on impact of sea salt aerosols on numerical weather prediction during low precipitation events. And finally, study on "Impact of regional afforestation on climatic conditions in metropolitan areas: case study of Copenhagen" with focus on impact of forest and land-cover change on formation and development of temperature regimes in the Copenhagen metropolitan area of Denmark. Selected results and findings will be presented and discussed.

  19. Source apportionment of particulate pollutants in the atmosphere over the Northern Yellow Sea

    Science.gov (United States)

    Wang, L.; Qi, J. H.; Shi, J. H.; Chen, X. J.; Gao, H. W.

    2013-05-01

    Atmospheric aerosol samples were collected over the Northern Yellow Sea of China during the years of 2006 and 2007, in which the Total Carbon (TC), Cu, Pb, Cd, V, Zn, Fe, Al, Na+, Ca2+, Mg2+, NH4+, NO3-, SO42-, Cl-, and K+ were measured. The principle components analysis (PCA) and positive matrix factorization (PMF) receptor models were used to identify the sources of particulate matter. The results indicated that seven factors contributed to the atmospheric particles over the Northern Yellow Sea, i.e., two secondary aerosols (sulfate and nitrate), soil dust, biomass burning, oil combustion, sea salt, and metal smelting. When the whole database was considered, secondary aerosol formation contributed the most to the atmospheric particle content, followed by soil dust. Secondary aerosols and soil dust consisted of 65.65% of the total mass of particulate matter. The results also suggested that the aerosols over the North Yellow Sea were heavily influenced by ship emission over the local sea area and by continental agricultural activities in the northern China, indicating by high loading of V in oil combustion and high loading of K+ in biomass burning. However, the contribution of each factor varied greatly over the different seasons. In spring and autumn, soil dust and biomass burning were the dominant factors. In summer, heavy oil combustion contributed the most among these factors. In winter, secondary aerosols were major sources. Backward trajectories analysis indicated the 66% of air mass in summer was from the ocean, while the air mass is mainly from the continent in other seasons.

  20. Lidar data assimilation for improved analyses of volcanic aerosol events

    Science.gov (United States)

    Lange, Anne Caroline; Elbern, Hendrik

    2014-05-01

    Observations of hazardous events with release of aerosols are hardly analyzable by today's data assimilation algorithms, without producing an attenuating bias. Skillful forecasts of unexpected aerosol events are essential for human health and to prevent an exposure of infirm persons and aircraft with possibly catastrophic outcome. Typical cases include mineral dust outbreaks, mostly from large desert regions, wild fires, and sea salt uplifts, while the focus aims for volcanic eruptions. In general, numerical chemistry and aerosol transport models cannot simulate such events without manual adjustments. The concept of data assimilation is able to correct the analysis, as long it is operationally implemented in the model system. Though, the tangent-linear approximation, which describes a substantial precondition for today's cutting edge data assimilation algorithms, is not valid during unexpected aerosol events. As part of the European COPERNICUS (earth observation) project MACC II and the national ESKP (Earth System Knowledge Platform) initiative, we developed a module that enables the assimilation of aerosol lidar observations, even during unforeseeable incidences of extreme emissions of particulate matter. Thereby, the influence of the background information has to be reduced adequately. Advanced lidar instruments comprise on the one hand the aspect of radiative transfer within the atmosphere and on the other hand they can deliver a detailed quantification of the detected aerosols. For the assimilation of maximal exploited lidar data, an appropriate lidar observation operator is constructed, compatible with the EURAD-IM (European Air Pollution and Dispersion - Inverse Model) system. The observation operator is able to map the modeled chemical and physical state on lidar attenuated backscatter, transmission, aerosol optical depth, as well as on the extinction and backscatter coefficients. Further, it has the ability to process the observed discrepancies with lidar

  1. Marine aerosol distribution and variability over the pristine Southern Indian Ocean

    Science.gov (United States)

    Mallet, Paul-Étienne; Pujol, Olivier; Brioude, Jérôme; Evan, Stéphanie; Jensen, Andrew

    2018-06-01

    This paper presents an 8-year (2005-2012 inclusive) study of the marine aerosol distribution and variability over the Southern Indian Ocean, precisely in the area { 10 °S - 40 °S ; 50 °E - 110 °E } which has been identified as one of the most pristine regions of the globe. A large dataset consisting of satellite data (POLDER, CALIOP), AERONET measurements at Saint-Denis (French Réunion Island) and model reanalysis (MACC), has been used. In spite of a positive bias of about 0.05 between the AOD (aerosol optical depth) given by POLDER and MACC on one hand and the AOD measured by AERONET on the other, consistent results for aerosol distribution and variability over the area considered have been obtained. First, aerosols are mainly confined below 2km asl (above sea level) and are dominated by sea salt, especially in the center of the area of interest, with AOD ≤ 0 . 1. This zone is the most pristine and is associated with the position of the Mascarene anticyclone. There, the direct radiative effect is assessed around - 9 Wm-2 at the top of the atmosphere and probability density functions of the AOD s are leptokurtic lognormal functions without any significant seasonal variation. It is also suggested that the Madden-Jullian oscillation impacts sea salt emissions in the northern part of the area considered by modifying the state of the ocean surface. Finally, this area is surrounded in the northeast and the southwest by seasonal Australian and South African intrusions (AOD > 0.1) ; throughout the year, the ITCZ seems to limit continental contaminations from Asia. Due to the long period of time considered (almost a decade), this paper completes and strengthens results of studies based on observations performed during previous specific field campaigns.

  2. Size-resolved mass concentrations of iron oxide aerosols and size-resolved number concentrations of iron oxide aerosols collected from King Air aircraft in Yellow Sea and East China Sea from 2013-02-14 to 2013-03-10 (NCEI Accession 0162201)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains size-resolved mass concentrations of iron oxide aerosols and size-resolved number concentrations of iron oxide aerosols, measured using the...

  3. Impact of North America on the aerosol composition in the North Atlantic free troposphere

    Directory of Open Access Journals (Sweden)

    M. I. García

    2017-06-01

    Full Text Available In the AEROATLAN project we study the composition of aerosols collected over  ∼  5 years at Izaña Observatory (located at  ∼  2400 m a.s.l. in Tenerife, the Canary Islands under the prevailing westerly airflows typical of the North Atlantic free troposphere at subtropical latitudes and midlatitudes. Mass concentrations of sub-10 µm aerosols (PM10 carried by westerly winds to Izaña, after transatlantic transport, are typically within the range 1.2 and 4.2 µg m−3 (20th and 80th percentiles. The main contributors to background levels of aerosols (PM10 within the 1st–50th percentiles  =  0.15–2.54 µg m−3 are North American dust (53 %, non-sea-salt sulfate (14 % and organic matter (18 %. High PM10 events (75th–95th percentiles  ≈  4.0–9.0 µg m−3 are prompted by dust (56 %, organic matter (24 % and non-sea-salt sulfate (9 %. These aerosol components experience a seasonal evolution explained by (i their spatial distribution in North America and (ii the seasonal shift of the North American outflow, which migrates from low latitudes in winter (∼  32° N, January–March to high latitudes in summer (∼  52° N, August–September. The westerlies carry maximum loads of non-sea-salt sulfate, ammonium and organic matter in spring (March–May, of North American dust from midwinter to mid-spring (February–May and of elemental carbon in summer (August–September. Our results suggest that a significant fraction of organic aerosols may be linked to sources other than combustion (e.g. biogenic; further studies are necessary for this topic. The present study suggests that long-term evolution of the aerosol composition in the North Atlantic free troposphere will be influenced by air quality policies and the use of soils (potential dust emitter in North America.

  4. The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08: an overview

    Directory of Open Access Journals (Sweden)

    M. Pikridas

    2010-07-01

    Full Text Available A month (4 May to 8 June 2008 of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08 was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption. Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1 and organics for 28%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%, sea salt (24% and nitrates (16%. The organic carbon to elemental carbon (OC/EC ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10 and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine, each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.

  5. Evaluation of operational forecast model of aerosol transportation using ceilometer network measurements

    Science.gov (United States)

    Chan, Ka Lok; Wiegner, Matthias; Flentje, Harald; Mattis, Ina; Wagner, Frank; Gasteiger, Josef; Geiß, Alexander

    2017-04-01

    Due to technical improvements of ceilometers in recent years, ceilometer measurements are not only limited to determine cloud base heights but also providing information on the vertical aerosol distribution. Therefore, several national weather services implemented ceilometer networks. These measurements are e.g. valuable for the evaluation of the chemical transport model simulations. In this study, we present comparisons of European Centre for Medium-Range Weather Forecast Integrated Forecast System (ECMWF-IFS) model simulation of aerosol backscatter coefficients with ceilometer network measurements operated by the German weather service (DWD) . Five different types of aerosol are available in the model simulations which include two natural aerosols, sea salt and dust. The other three aerosol types, i.e. sulfate, organic carbon and black carbon, have significant anthropogenic contributions. As the model output provides mass mixing ratios of the above mentioned types of aerosol and the ceilometers measure attenuated backscatter (β∗) provided that calibration took place, it is necessary to determine a common physical quantity for the comparison. We have chosen the aerosol backscatter coefficient (β) for this purpose. The β-profiles are calculated from the mass mixing ratios of the model output assuming the inherent aerosol microphysics properties. It shall be emphasized that in the model calculations, all particles are assumed to be spherical. We have examined the sensitivity of the intercomparison on the hygroscopic growth of particles and on the role of particle shape. Our results show that the hygroscopic growth of particle is crucial (up to a factor of 22) in converting the model output to backscatter coefficient profiles whereas the effect of non-sphericity of dust particles is comparably small (˜44%). Furthermore, the calibration of the ceilometer signals can be an issue. The agreements between modeled and retrieved β-profiles show different

  6. Properties of Arctic Aerosol Particles and Residuals of Warm Clouds: Cloud Activation Efficiency and the Aerosol Indirect Effect

    Science.gov (United States)

    Zelenyuk, A.; Imre, D. G.; Leaitch, R.; Ovchinnikov, M.; Liu, P.; Macdonald, A.; Strapp, W.; Ghan, S. J.; Earle, M. E.

    2012-12-01

    Single particle mass spectrometer, SPLAT II, was used to characterize the size, composition, number concentration, density, and shape of individual Arctic spring aerosol. Background particles, particles above and below the cloud, cloud droplet residuals, and interstitial particles were characterized with goal to identify the properties that separate cloud condensation nuclei (CCN) from background aerosol particles. The analysis offers a comparison between warm clouds formed on clean and polluted days, with clean days having maximum particle concentrations (Na) lower than ~250 cm-3, as compared with polluted days, in which maximum concentration was tenfold higher. On clean days, particles were composed of organics, organics mixed with sulfates, biomass burning (BB), sea salt (SS), and few soot and dust particles. On polluted days, BB, organics associated with BB, and their mixtures with sulfate dominated particle compositions. Based on the measured compositions and size distributions of cloud droplet residuals, background aerosols, and interstitial particles, we conclude that these three particle types had virtually the same compositions, which means that cloud activation probabilities were surprisingly nearly composition independent. Moreover, these conclusions hold in cases in which less than 20% or more than 90% of background particles got activated. We concluded that for the warm clouds interrogated in this study particle size played a more important factor on aerosol CCN activity. Comparative analysis of all studied clouds reveals that aerosol activation efficiency strongly depends on the aerosol concentrations, such that at Na <200 cm-3, nearly all particles activate, and at higher concentrations the activation efficiency is lower. For example, when Na was greater than 1500 cm-3, less than ~30% of particles activated. The data suggest that as the number of nucleated droplets increases, condensation on existing droplets effectively competes with particle

  7. Organic aerosols

    International Nuclear Information System (INIS)

    Penner, J.E.

    1994-01-01

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

  8. A history of salt.

    Science.gov (United States)

    Cirillo, M; Capasso, G; Di Leo, V A; De Santo, N G

    1994-01-01

    The medical history of salt begins in ancient times and is closely related to different aspects of human history. Salt may be extracted from sea water, mineral deposits, surface encrustations, saline lakes and brine springs. In many inland areas, wood was used as a fuel source for evaporation of brine and this practice led to major deafforestation in central Europe. Salt played a central role in the economies of many regions, and is often reflected in place names. Salt was also used as a basis for population censuses and taxation, and salt monopolies were practised in many states. Salt was sometimes implicated in the outbreak of conflict, e.g. the French Revolution and the Indian War of Independence. Salt has also been invested with many cultural and religious meanings, from the ancient Egyptians to the Middle Ages. Man's innate appetite for salt may be related to his evolution from predominantly vegetarian anthropoids, and it is noteworthy that those people who live mainly on protein and milk or who drink salty water do not generally salt their food, whereas those who live mainly on vegetables, rice and cereals use much more salt. Medicinal use tended to emphasize the positive aspects of salt, e.g. prevention of putrefaction, reduction of tissue swelling, treatment of diarrhea. Evidence was also available to ancient peoples of its relationship to fertility, particularly in domestic animals. The history of salt thus represents a unique example for studying the impact of a widely used dietary substance on different important aspects of man's life, including medical philosophy.

  9. Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

    International Nuclear Information System (INIS)

    Orsini, C.M.Q.; Tabacniks, M.H.; Artaxo Netto, P.E.; Andrade, M.F.; Kerr, A.

    1986-02-01

    Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author) [pt

  10. Radioactive aerosols

    International Nuclear Information System (INIS)

    Chamberlain, A.C.

    1991-01-01

    Radon. Fission product aerosols. Radioiodine. Tritium. Plutonium. Mass transfer of radioactive vapours and aerosols. Studies with radioactive particles and human subjects. Index. This paper explores the environmental and health aspects of radioactive aerosols. Covers radioactive nuclides of potential concern to public health and applications to the study of boundary layer transport. Contains bibliographic references. Suitable for environmental chemistry collections in academic and research libraries

  11. Aerosolization, Chemical Characterization, Hygroscopicity and Ice Formation of Marine Biogenic Particles

    Science.gov (United States)

    Alpert, P. A.; Radway, J.; Kilthau, W.; Bothe, D.; Knopf, D. A.; Aller, J. Y.

    2013-12-01

    liquid-to-ice phase transformations. Aqueous and dry aerosolized particles from biologically active mesocosm water were found to efficiently nucleate ice exposed to supersaturated water vapor. The majority of particles, including those nucleating ice, consisted of a sea salt core coated with organic material dominated by the carboxyl functional group, and corresponded to a particle type commonly found in marine air. Our results provide improved estimates of marine aerosol production, chemical composition, and hygroscopicity, as well as an accurate physical and chemical representation of ice nucleation by marine biogenic aerosol particles for use in cloud and climate models.

  12. Aerosol optical properties and precipitable water vapor column in the atmosphere of Norway.

    Science.gov (United States)

    Muyimbwa, Dennis; Frette, Øyvind; Stamnes, Jakob J; Ssenyonga, Taddeo; Chen, Yi-Chun; Hamre, Børge

    2015-02-20

    Between February 2012 and April 2014, we measured and analyzed direct solar radiances at a ground-based station in Bergen, Norway. We discovered that the spectral aerosol optical thickness (AOT) and precipitable water vapor column (PWVC) retrieved from these measurements have a seasonal variation with highest values in summer and lowest values in winter. The highest value of the monthly median AOT at 440 nm of about 0.16 was measured in July and the lowest of about 0.04 was measured in December. The highest value of the monthly median PWVC of about 2.0 cm was measured in July and the lowest of about 0.4 cm was measured in December. We derived Ångström exponents that were used to deduce aerosol particle size distributions. We found that coarse-mode aerosol particles dominated most of the time during the measurement period, but fine-mode aerosol particles dominated during the winter seasons. The derived Ångström exponent values suggested that aerosols containing sea salt could have been dominating at this station during the measurement period.

  13. AOD distributions and trends of major aerosol species over a selection of the world’s most populated cities based on the 1st Version of NASA’s MERRA Aerosol Reanalysis

    Science.gov (United States)

    Provençal, Simon; Kishcha, Pavel; da Silva, Arlindo M.; Elhacham, Emily; Alpert, Pinhas

    2018-01-01

    NASA recently extended the Modern-Era Retrospective Analysis for Research and Application (MERRA) with an atmospheric aerosol reanalysis which includes five particulate species: sulfate, organic matter, black carbon, mineral dust and sea salt. The MERRA Aerosol Reanalysis (MERRAero) is an innovative tool to study air quality issues around the world for its global and constant coverage and its distinction of aerosol speciation expressed in the form of aerosol optical depth (AOD). The purpose of this manuscript is to apply MERRAero to the study of urban air pollution at the global scale by analyzing the AOD over a period of 13 years (2003–2015) and over a selection of 200 of the world’s most populated cities in order to assess the impacts of urbanization, industrialization, air quality regulations and regional transport which affect urban aerosol load. Environmental regulations and the recent global economic recession have helped to decrease the AOD and sulfate aerosols in most cities in North America, Europe and Japan. Rapid industrialization in China over the last two decades resulted in Chinese cities having the highest AOD values in the world. China has nevertheless recently implemented emission control measures which are showing early signs of success in many cities of Southern China where AOD has decreased substantially over the last 13 years. The AOD over South American cities, which is dominated by carbonaceous aerosols, has also decreased over the last decade due to an increase in commodity prices which slowed deforestation activities in the Amazon rainforest. At the opposite, recent urbanization and industrialization in India and Bangladesh resulted in a strong increase of AOD, sulfate and carbonaceous aerosols in most cities of these two countries. The AOD over most cities in Northern Africa and Western Asia changed little over the last decade. Emissions of natural aerosols, which cities in these two regions tend to be mostly composed of, don’t tend

  14. Size distribution measurements and chemical analysis of aerosol components

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.

    1995-12-31

    The principal aims of this work were to improve the existing methods for size distribution measurements and to draw conclusions about atmospheric and in-stack aerosol chemistry and physics by utilizing size distributions of various aerosol components measured. A sample dissolution with dilute nitric acid in an ultrasonic bath and subsequent graphite furnace atomic absorption spectrometric analysis was found to result in low blank values and good recoveries for several elements in atmospheric fine particle size fractions below 2 {mu}m of equivalent aerodynamic particle diameter (EAD). Furthermore, it turned out that a substantial amount of analyses associated with insoluble material could be recovered since suspensions were formed. The size distribution measurements of in-stack combustion aerosols indicated two modal size distributions for most components measured. The existence of the fine particle mode suggests that a substantial fraction of such elements with two modal size distributions may vaporize and nucleate during the combustion process. In southern Norway, size distributions of atmospheric aerosol components usually exhibited one or two fine particle modes and one or two coarse particle modes. Atmospheric relative humidity values higher than 80% resulted in significant increase of the mass median diameters of the droplet mode. Important local and/or regional sources of As, Br, I, K, Mn, Pb, Sb, Si and Zn were found to exist in southern Norway. The existence of these sources was reflected in the corresponding size distributions determined, and was utilized in the development of a source identification method based on size distribution data. On the Finnish south coast, atmospheric coarse particle nitrate was found to be formed mostly through an atmospheric reaction of nitric acid with existing coarse particle sea salt but reactions and/or adsorption of nitric acid with soil derived particles also occurred. Chloride was depleted when acidic species reacted

  15. Inverse Relationship of Marine Aerosol and Dust in Antarctic Ice with Fine-Grained Sediment in the South Atlantic Ocean: Implications for Sea-Ice Coverage and Wind Strength

    Directory of Open Access Journals (Sweden)

    Sharon L. Kanfoush

    2012-03-01

    Full Text Available This research seeks to test the hypothesis that natural gamma radiation (NGR from Ocean Drilling Program Site 1094, which displays variability over the last glacial-interglacial cycle similar to dust in the Vostok ice core, reflects fine-grained terrigenous sediment delivered by eolian processes. Grain size was measured on 400 samples spanning 0–20 m in a composite core. Accumulation of the <63μ size fraction at Site 1094 and dust in Vostok exhibit a negative correlation, suggesting the fine sediments are not dominantly eolian. However the technique used for grain size measurements cannot distinguish between terrigenous and biogenous materials; therefore it is possible much fine-grained material is diatoms. An inverse correlation between fine sediments and NGR supports this interpretation, and implies terrigenous materials were at times diluted by microfossils from high biological productivity. Fine marine sediments correlate positively with temperature and negatively with marine aerosol Na+ in Vostok. One plausible explanation is extensive sea-ice of cold intervals steepened ocean-continent temperature gradients, intensified winds, and led to increased transport of dust and marine aerosol to Antarctica yet also reduced biological productivity at Site 1094. Such a reduction despite increases in NGR, potentially representing Fe-rich dust influx, would require light limitation or stratification associated with sea-ice.

  16. Seven year satellite observations of the mean structures and variabilities in the regional aerosol distribution over the oceanic areas around the Indian subcontinent

    Directory of Open Access Journals (Sweden)

    S. K. Nair

    2005-09-01

    Full Text Available Aerosol distribution over the oceanic regions around the Indian subcontinent and its seasonal and interannual variabilities are studied using the aerosol optical depth (AOD derived from NOAA-14 and NOAA-16 AVHRR data for the period of November 1995–December 2003. The air-mass types over this region during the Asian summer monsoon season (June–September are significantly different from those during the Asian dry season (November–April. Hence, the aerosol loading and its properties over these oceanic regions are also distinctly different in these two periods. During the Asian dry season, the Arabian Sea and Bay of Bengal are dominated by the transport of aerosols from Northern Hemispheric landmasses, mainly the Indian subcontinent, Southeast Asia and Arabia. This aerosol transport is rather weak in the early part of the dry season (November–January compared to that in the later period (February–April. Large-scale transport of mineral dust from Arabia and the production of sea-salt aerosols, due to high surface wind speeds, contribute to the high aerosol loading over the Arabian Sea region during the summer monsoon season. As a result, the monthly mean AOD over the Arabian Sea shows a clear annual cycle with the highest values occurring in July. The AOD over the Bay of Bengal and the Southern Hemisphere Indian Ocean also displays an annual cycle with maxima during March and October, respectively. The amplitude of the annual variation is the largest in coastal Arabia and the least in the Southern Hemisphere Indian Ocean. The interannual variability in AOD is the largest over the Southeast Arabian Sea (seasonal mean AOD varies from 0.19 to 0.42 and the northern Bay of Bengal (seasonal mean AOD varies from 0.24 to 0.39 during the February–April period and is the least over the Southern Hemisphere Indian Ocean. This study also investigates the altitude regions and pathways of dominant aerosol transport by combining the AOD distribution with

  17. Evolution of salt diapir and karst morphology during the last glacial cycle: Effects of sea-level oscillation, diapir and regional uplift, and erosion (Persian Gulf, Iran)

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Filippi, Michal; Zare, M.; Churáčková, Z.; Asadi, N.; Fuchs, M.; Adamovič, Jiří

    2010-01-01

    Roč. 121, 3/4 (2010), s. 291-304 ISSN 0169-555X R&D Projects: GA AV ČR KJB315040801; GA AV ČR(CZ) KJB301110501 Institutional research plan: CEZ:AV0Z30130516 Keywords : salt karst * salt diapir * salt cave * uplift rate * Persian Gulf Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.352, year: 2010

  18. Seasonal variability of aerosol concentration and size distribution in Cape Verde using a continuous aerosol optical spectrometer

    Directory of Open Access Journals (Sweden)

    Casimiro Adrião Pio

    2014-05-01

    Full Text Available One year of, almost continuous, measurements of aerosol optical properties and chemical composition were performed at the outskirts of Praia, Santiago Island, Cape Verde, within the framework of CV-DUST (Atmospheric aerosol in Cape Verde region: seasonal evaluation of composition, sources and transport research project, during 2011. This article reports the aerosol number and mass concentration measurements using a GRIMM Optical Aerosol Spectrometer that provides number size discrimination into 31 size ranges from 0.25 to 32 µm. Time series of 5 min average PM10 concentrations revealed peak values higher than 1000 µg.m-3 during winter dust storm events originating over Northern Africa. The 24 hours average concentrations exceeded the World Health Organization (WHO guidelines for PM2.5 and PM10 in 20% and 30% of the 2001 days, respectively. Annual average mass concentrations (±standard deviation for PM1, PM2.5 and PM10 were 5±5, 19±21 and 48±64 µg.m-3, respectively. The annual PM2.5 and PM10 values were also above the limits prescribed by the WHO (10 and 20 µg.m-3, respectively. The aerosol mass size distribution revealed two main modes for particles smaller than 10 µm: a fine mode (0.7-0.8 µm, which possibly results of gas to particle conversion processes; and a coarse mode with maxima at 3-4 µm, which is associated with desert dust and sea salt sources. Within the coarse mode two sub-modes with maxima at 5-6 µm and 10-12 µm were frequently present.

  19. Clouds and aerosols in Puerto Rico - a new evaluation

    Science.gov (United States)

    Allan, J. D.; Baumgardner, D.; Raga, G. B.; Mayol-Bracero, O. L.; Morales-García, F.; García-García, F.; Montero-Martínez, G.; Borrmann, S.; Schneider, J.; Mertes, S.; Walter, S.; Gysel, M.; Dusek, U.; Frank, G. P.; Krämer, M.

    2008-03-01

    The influence of aerosols, both natural and anthropogenic, remains a major area of uncertainty when predicting the properties and behaviour of clouds and their influence on climate. In an attempt to better understand warm cloud formation in a tropical marine environment, a period of intensive measurements took place in December 2004 in Puerto Rico, using some of the latest developments in online instrumentation such as aerosol mass spectrometers, cloud condensation nuclei counters and a hygroscopicity tandem differential mobility analyser. Simultaneous online measurements of aerosol size distributions, composition, hygroscopicity and optical properties were made near the lighthouse of Cape San Juan in the north-eastern corner of the island and at the top of East Peak mountain (1040 m a.s.l.), the two sites separated by 17 km. Additional measurements of the cloud droplet residual and interstitial aerosol properties were made at the mountain site, accompanied by measurements of cloud droplet size distributions, liquid water content and the chemical composition of cloud and rain water samples. Both aerosol composition and cloud properties were found to be sensitive to wind sector. Air from the east-northeast (ENE) was mostly free of anthropogenic influences, the submicron fraction being mainly composed of non-sea salt sulphate, while that from the east-southeast (ESE) was found to be moderately influenced by populated islands upwind, adding smaller (residual particles and concentrations of cloudwater nitrate, sulphate and insoluble material increased during polluted conditions. Previous studies in Puerto Rico had reported the presence of a significant non-anthropogenic organic fraction in the aerosols measured and concluded that this was a factor controlling the in situ cloud properties. However, this was not observed in our case. In contrast to the 1.00±0.14 μg m-3 of organic carbon measured in 1992 and 1995, the organic matter measured in the current study of 0

  20. Investigation of the seasonal variations of aerosol physicochemical properties and their impact on cloud condensation nuclei number concentration

    Science.gov (United States)

    Logan, Timothy S.

    strongly absorbing carbonaceous particles generated from the flaming combustion mode. The cases represented complex mixtures of the flaming and smoldering combustion phases. Lastly, SQ3 is addressed by using a multi-platform dataset from the Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) Graciosa, Azores, 2009-2010 field campaign. The seasonal aerosol particle volume and number size distributions, AOD, and AEAOD during the CAP-MBL campaign have shown that a low overall mean AOD440 of 0.12 denoted a clean environment over this region that typically contains MBL sea salt. In terms of aerosol volume, a bimodal signal was prominent where the coarse mode influence (r ≥ 1 μm) dominated that of the fine mode (r < 1 μm) throughout the year. However, there are considerable continental fine mode aerosols advected to the Azores region during summer months, including Saharan mineral dust, volcanic ash, biomass smoke, and pollution from North American as identified by HYSPLIT backward trajectories. These aerosol types have been shown to have impacts on MBL cloud condensation nuclei (CCN) that are likely different from coarse mode marine aerosols (e.g., sea salt) (Remillard et al. 2014; Wood et al. 2014). The alternating presence of dominant clean air masses with periodic episodes of polluted air masses will provide a substantial variety in aerosol properties during the summer. This will provide a great opportunity to investigate the interactions between aerosol and cloud properties in terms of the aerosol indirect effect (AIE).

  1. Supra-salt normal fault growth during the rise and fall of a diapir: Perspectives from 3D seismic reflection data, Norwegian North Sea

    Science.gov (United States)

    Tvedt, Anette B. M.; Rotevatn, Atle; Jackson, Christopher A.-L.

    2016-10-01

    Normal faulting and the deep subsurface flow of salt are key processes controlling the structural development of many salt-bearing sedimentary basins. However, our detailed understanding of the spatial and temporal relationship between normal faulting and salt movement is poor due to a lack of natural examples constraining their geometric and kinematic relationship in three-dimensions. To improve our understanding of these processes, we here use 3D seismic reflection and borehole data from the Egersund Basin, offshore Norway, to determine the structure and growth of a normal fault array formed during the birth, growth and decay of an array of salt structures. We show that the fault array and salt structures developed in response to: (i) Late Triassic-to-Middle Jurassic extension, which involved thick-skinned, sub-salt and thin-skinned supra-salt faulting with the latter driving reactive diapirism; (ii) Early Cretaceous extensional collapse of the walls; and (iii) Jurassic-to-Neogene, active and passive diapirism, which was at least partly coeval with and occurred along-strike from areas of reactive diapirism and wall collapse. Our study supports physical model predictions, showcasing a three-dimensional example of how protracted, multiphase salt diapirism can influence the structure and growth of normal fault arrays.

  2. Aerosol effects in radiation transfer

    International Nuclear Information System (INIS)

    Binenko, V.I.; Harshvardhan, H.

    1993-01-01

    The radiative properties and effects of aerosols are assessed for the following aerosol sources: relatively clean background aerosol, dust storms and dust outbreaks, anthropogenic pollution, and polluted cloud layers. Studies show it is the submicron aerosol fraction that plays a dominant radiative role in the atmosphere. The radiative effect of the aerosol depends not only on its loading but also on the underlying surface albedo and on solar zenith angle. It is only with highly reflecting surfaces such as Arctic ice that aerosols have a warming effect. Radiometric, microphysical, mineral composition, and refractive index measurements are presented for dust and in particular for the Saharan aerosol layer (SAL). Short-wave radiative heating of the atmosphere is caused by the SAL and is due mainly to absorption. However, the SAL does not contribute significantly to the long-wave thermal radiation budget. Field program studies of the radiative effects of aerosols are described. Anthropogenic aerosols deplete the incoming solar radiation. A case field study for a regional Ukrainian center is discussed. The urban aerosol causes a cooling of metropolitan centers, compared with outlying areas, during the day, which is followed by a warming trend at night. In another study, an increase in turbidity by a factor of 3 due to increased industrialization for Mexico City is noted, together with a drop in atmospheric transmission by 10% over a 50-year period. Numerous studies are cited that demonstrate that anthropogenic aerosols affect both the microphysical and radiative properties of clouds, which in turn affect regional climate. Particles acting as cloud nuclei are considered to have the greatest indirect effect on cloud absorptivity of short-wave radiation. Satellite observations show that low-level stratus clouds contaminated by ship exhaust at sea lead to an increase in cloud albedo

  3. Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

    Science.gov (United States)

    Russell, L. M.

    2017-12-01

    Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

  4. Exploring Climatology and Long-Term Variations of Aerosols from NASA Reanalysis MERRA-2 with Giovanni

    Science.gov (United States)

    Shen, Suhung; Ostrenga, Dana; Vollmer, Bruce; Li, Zhanqing

    2016-01-01

    Dust plays important roles in energy cycle and climate variations. The dust deposition is the major source of iron in the open ocean, which is an essential micronutrient for phytoplankton growth and therefore may influence the ocean uptake of atmospheric CO2. Mineral dust can also act as fertilizer for forests over long time periods. Over 35 years of simulated global aerosol products from NASA atmospheric reanalysis, second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) are available from NASA Goddard Earth Science Data and Information Services Center (GES DISC). The MERRA-2 covers the period 1980-present, continuing as an ongoing climate analysis. Aerosol assimilation is included throughout the period, using MODIS, MISR, AERONET, and AVHRR (in the pre-EOS period). The aerosols are assimilated by using MERRA-2 aerosol model, which interact directly with the radiation parameterization, and radiatively coupled with atmospheric model dynamics in the Goddard Earth Observing System Model, Version 5 (GEOS-5). Dust deposition data along with other major aerosol compositions (e.g. black carbon, sea salt, and sulfate, etc.) are simulated as dry and wet deposition, respectively. The hourly and monthly data are available at spatial resolution of 0.5ox0.625o (latitude x longitude). Quick data exploration of climatology and interannual variations of MERRA-2 aerosol can be done through the online visualization and analysis tool, Giovanni. This presentation, using dust deposition as an example, demonstrates a number of MERRA-2 data services at GES DISC. Global distributions of dust depositions, and their seasonal and inter-annual variations are investigated from MERRA-2 monthly aerosol products.

  5. Global direct radiative forcing by process-parameterized aerosol optical properties

    Science.gov (United States)

    KirkevâG, Alf; Iversen, Trond

    2002-10-01

    A parameterization of aerosol optical parameters is developed and implemented in an extended version of the community climate model version 3.2 (CCM3) of the U.S. National Center for Atmospheric Research. Direct radiative forcing (DRF) by monthly averaged calculated concentrations of non-sea-salt sulfate and black carbon (BC) is estimated. Inputs are production-specific BC and sulfate from [2002] and background aerosol size distribution and composition. The scheme interpolates between tabulated values to obtain the aerosol single scattering albedo, asymmetry factor, extinction coefficient, and specific extinction coefficient. The tables are constructed by full calculations of optical properties for an array of aerosol input values, for which size-distributed aerosol properties are estimated from theory for condensation and Brownian coagulation, assumed distribution of cloud-droplet residuals from aqueous phase oxidation, and prescribed properties of the background aerosols. Humidity swelling is estimated from the Köhler equation, and Mie calculations finally yield spectrally resolved aerosol optical parameters for 13 solar bands. The scheme is shown to give excellent agreement with nonparameterized DRF calculations for a wide range of situations. Using IPCC emission scenarios for the years 2000 and 2100, calculations with an atmospheric global cliamte model (AFCM) yield a global net anthropogenic DRF of -0.11 and 0.11 W m-2, respectively, when 90% of BC from biomass burning is assumed anthropogenic. In the 2000 scenario, the individual DRF due to sulfate and BC has separately been estimated to -0.29 and 0.19 W m-2, respectively. Our estimates of DRF by BC per BC mass burden are lower than earlier published estimates. Some sensitivity tests are included to investigate to what extent uncertain assumptions may influence these results.

  6. Nuclear microprobe analysis and source apportionment of individual atmospheric aerosol particles

    International Nuclear Information System (INIS)

    Artaxo, P.; Rabello, M.L.C.; Watt, F.; Grime, G.; Swietlicki, E.

    1993-01-01

    In atmospheric aerosol reserach, one key issue is to determine the sources of the airborne particles. Bulk PIXE analysis coupled with receptor modeling provides a useful, but limited view of the aerosol sources influencing one particular site or sample. The scanning nuclear microprobe (SNM) technique is a microanalytical technique that gives unique information on individual aerosol particles. In the SNM analyses a 1.0 μm size 2.4 MeV proton beam from the Oxford SNM was used. The trace elements with Z>11 were measured by the particle induced X-ray emission (PIXE) method with detection limits in the 1-10 ppm range. Carbon, nitrogen and oxygen are measured simultaneously using Rutherford backscattering spectrometry (RBS). Atmospheric aerosol particles were collected at the Brazilian Antarctic Station and at biomass burning sites in the Amazon basin tropical rain forest in Brazil. In the Antarctic samples, the sea-salt aerosol particles were clearly predominating, with NaCl and CaSO 4 as major compounds with several trace elements as Al, Si, P, K, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Pb. Factor analysis of the elemental data showed the presence of four components: 1) Soil dust particles; 2) NaCl particles; 3) CaSO 4 with Sr; and 4) Br and Mg. Strontium, observed at 20-100 ppm levels, was always present in the CaSO 4 particles. The hierarchical cluster procedure gave results similar to the ones obtained through factor analysis. For the tropical rain forest biomass burning aerosol emissions, biogenic particles with a high organic content dominate the particle population, while K, P, Ca, Mg, Zn, and Si are the dominant elements. Zinc at 10-200 ppm is present in biogenic particles rich in P and K. The quantitative aspects and excellent detection limits make SNM analysis of individual aerosol particles a very powerful analytical tool. (orig.)

  7. Global modelling of secondary organic aerosol in the troposphere: a sensitivity analysis

    Directory of Open Access Journals (Sweden)

    K. Tsigaridis

    2003-01-01

    Full Text Available A global 3-dimensional chemistry/transport model able to describe O3, NOx, Volatile Organic Compounds (VOC, sulphur and NH3 chemistry has been extended to simulate the temporal and spatial distribution of primary and secondary carbonaceous aerosols in the troposphere focusing on Secondary Organic Aerosol (SOA formation. A number of global simulations have been performed to determine a possible range of annual global SOA production and investigate uncertainties associated with the model results. The studied uncertainties in the SOA budget have been evaluated to be in decreasing importance: the potentially irreversible sticking of the semi-volatile compounds on aerosols, the enthalpy of vaporization of these compounds, the partitioning of SOA on non-carbonaceous aerosols, the conversion of aerosols from hydrophobic to hydrophilic, the emissions of primary carbonaceous aerosols, the chemical fate of the first generation products and finally the activity coefficient of the condensable species. The large uncertainties associated with the emissions of VOC and the adopted simplification of chemistry have not been investigated in this study. Although not all sources of uncertainties have been investigated, according to our calculations, the above factors within the experimental range of variations could result to an overall uncertainty of about a factor of 20 in the global SOA budget. The global annual SOA production from biogenic VOC might range from 2.5 to 44.5 Tg of organic matter per year, whereas that from anthropogenic VOC ranges from 0.05 to 2.62 Tg of organic matter per year. These estimates can be considered as a lower limit, since partitioning on coarse particles like nitrate, dust or sea-salt, together with the partitioning and the dissociation of the semi-volatile products in aerosol water has been neglected. Comparison of model results to observations, where available, shows a better agreement for the upper budget estimates than for the

  8. Sodium salt medium-chain fatty acids and Bacillus-based probiotic strategies to improve growth and intestinal health of gilthead sea bream (Sparus aurata

    Directory of Open Access Journals (Sweden)

    Paula Simó-Mirabet

    2017-12-01

    Full Text Available Background The increased demand for fish protein has led to the intensification of aquaculture practices which are hampered by nutritional and health factors affecting growth performance. To solve these problems, antibiotics have been used for many years in the prevention, control and treatment against disease as well as growth promoters to improve animal performance. Nowadays, the use of antibiotics in the European Union and other countries has been completely or partially banned as a result of the existence of antibiotic cross-resistance. Therefore, a number of alternatives, including enzymes, prebiotics, probiotics, phytonutrients and organic acids used alone or in combination have been proposed for the improvement of immunological state, growth performance and production in livestock animals. The aim of the present study was to evaluate two commercially available feed additives, one based on medium-chain fatty acids (MCFAs from coconut oil and another with a Bacillus-based probiotic, in gilthead sea bream (GSB, Sparus aurata, a marine farmed fish of high value in the Mediterranean aquaculture. Methods The potential benefits of adding two commercial feed additives on fish growth performance and intestinal health were assessed in a 100-days feeding trial. The experimental diets (D2 and D3 were prepared by supplementing a basal diet (D1 with MCFAs in the form of a sodium salt of coconut fatty acid distillate (DICOSAN®; Norel, Madrid, Spain, rich on C-12, added at 0.3% (D2 or with the probiotic Bacillus amyloliquefaciens CECT 5940, added at 0.1% (D3. The study integrated data on growth performance, blood biochemistry, histology and intestinal gene expression patterns of selected markers of intestinal function and architecture. Results MCFAs in the form of a coconut oil increased feed intake, growth rates and the surface of nutrient absorption, promoting the anabolic action of the somatotropic axis. The probiotic (D3 induced anti

  9. Coastal Antarctic aerosol: the seasonal pattern of its chemical composition and radionuclide content

    International Nuclear Information System (INIS)

    Wagenbach, D.; Goerlach, U.; Moser, K.; Muennich, K.O.

    1988-01-01

    At the German Antarctic research station (70 degrees S, 8 degrees W), long-term observations of the chemical and radio-chemical composition of atmospheric particulate matter were started in spring 1983. Based on the analysis of high-volume aerosol filters sampled continuously for nearly 5 years, concentration records of the following aerosol components are presented here: (a) major ions (sea-salt, sulfate, nitrate); (b) cosmogenic 7 Be and terrigeneous 210 Pb; (c) trace elements (crustal Mn, heavy metal Pb). All species mentioned, with the exception of stable and radioactive Pb, show annual cycles. The maximum occurs in austral summer for 7 Be, sulfate, and crustal Mn. For sea-salt, however, the maximum is found in local autumn, and for nitrate in local spring. In local summer, the enhanced 7 Be to 210 Pb ratio is attributed to intenser large scale vertical mixing. The pattern of total sulfate seems to be controlled by the nss-sulfate production from marine organo-sulfur species during local summer, whereas in polar night, nss-sulfate shows very low or even negative concentration. Crustal aerosol (indicated by Mn) shows a mean summer contribution of 16 ng/SCM which exceeds the mean winter level by more than a factor of two. Based on a mean wash-out ratio of 0.27x10 6 observed for 210 Pb bearing aerosol particles, a Pb snow concentration of 3.0 pg/g is deduced from the mean air concentration of 11 pg/SCM. (authors)

  10. The global aerosol-climate model ECHAM-HAM, version 2: sensitivity to improvements in process representations

    Directory of Open Access Journals (Sweden)

    K. Zhang

    2012-10-01

    Full Text Available This paper introduces and evaluates the second version of the global aerosol-climate model ECHAM-HAM. Major changes have been brought into the model, including new parameterizations for aerosol nucleation and water uptake, an explicit treatment of secondary organic aerosols, modified emission calculations for sea salt and mineral dust, the coupling of aerosol microphysics to a two-moment stratiform cloud microphysics scheme, and alternative wet scavenging parameterizations. These revisions extend the model's capability to represent details of the aerosol lifecycle and its interaction with climate. Nudged simulations of the year 2000 are carried out to compare the aerosol properties and global distribution in HAM1 and HAM2, and to evaluate them against various observations. Sensitivity experiments are performed to help identify the impact of each individual update in model formulation.

    Results indicate that from HAM1 to HAM2 there is a marked weakening of aerosol water uptake in the lower troposphere, reducing the total aerosol water burden from 75 Tg to 51 Tg. The main reason is the newly introduced κ-Köhler-theory-based water uptake scheme uses a lower value for the maximum relative humidity cutoff. Particulate organic matter loading in HAM2 is considerably higher in the upper troposphere, because the explicit treatment of secondary organic aerosols allows highly volatile oxidation products of the precursors to be vertically transported to regions of very low temperature and to form aerosols there. Sulfate, black carbon, particulate organic matter and mineral dust in HAM2 have longer lifetimes than in HAM1 because of weaker in-cloud scavenging, which is in turn related to lower autoconversion efficiency in the newly introduced two-moment cloud microphysics scheme. Modification in the sea salt emission scheme causes a significant increase in the ratio (from 1.6 to 7.7 between accumulation mode and coarse mode emission fluxes of

  11. 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.

  12. Methodology for assessing the concentrations of the primary marine aerosol in coastal areas

    International Nuclear Information System (INIS)

    Barsanti, P.; Briganti, G.; Cappelletti, A.; Marri, P.

    2009-01-01

    European and Italian regulations (DM 60/2002) fix for atmospheric particulate matter PM10 the threshold of 50 μg/m 3 as limit not to be exceeded more than 35 times per year (24 hour mean); unfortunately, such prescriptions do not distinguish anthropic contributions from natural ones (sea salt, Saharan sand, coastal erosion, volcanic ashes, etc.). The aim of this study is to set up a methodology in order to estimate sea salt emissions, both from open sea and surf zone, and to model atmospheric dispersion of marine aerosols. The proposed methodology, applied to the coastal zone between Massa Carrara and Viareggio (Tuscany, Italy), shows specific open sea emissions are generally very low in comparison with the surf zone ones: they are not negligible only with strong winds, but such meteorological conditions are neither persistent nor very frequent in the selected area. On the contrary, sea surf contributions are much more strong (at least 1 order of magnitude), peak-shaped and persistent then the first ones, and can lead to high PM10 concentration fields up to few kilometres inland. The comparison between model outputs and observations, in two points placed at 2000 and 4000 m from the shoreline, has shown an amount of sea salt in total PM10 even greater then 70% in mass. The existence of a surf zone, which can persist many hours or days even after a storm, can produce both elevated PM concentrations and gradients, mainly for light winds perpendicular to the shoreline. This work, supported by MINNI Project (www.minni.org), is suitable for other coastal areas as well and it is aimed to furnish an overview of marine particulate production and atmospheric dispersion processes; it is the starting point of an experimental investigation program, supported by institutional air quality authorities [it

  13. Indirect estimation of absorption properties for fine aerosol particles using AATSR observations: a case study of wildfires in Russia in 2010

    Science.gov (United States)

    Rodriguez, E.; Kolmonen, P.; Virtanen, T. H.; Sogacheva, L.; Sundstrom, A.-M.; de Leeuw, G.

    2015-08-01

    The Advanced Along-Track Scanning Radiometer (AATSR) on board the ENVISAT satellite is used to study aerosol properties. The retrieval of aerosol properties from satellite data is based on the optimized fit of simulated and measured reflectances at the top of the atmosphere (TOA). The simulations are made using a radiative transfer model with a variety of representative aerosol properties. The retrieval process utilizes a combination of four aerosol components, each of which is defined by their (lognormal) size distribution and a complex refractive index: a weakly and a strongly absorbing fine-mode component, coarse mode sea salt aerosol and coarse mode desert dust aerosol). These components are externally mixed to provide the aerosol model which in turn is used to calculate the aerosol optical depth (AOD). In the AATSR aerosol retrieval algorithm, the mixing of these components is decided by minimizing the error function given by the sum of the differences between measured and calculated path radiances at 3-4 wavelengths, where the path radiances are varied by varying the aerosol component mixing ratios. The continuous variation of the fine-mode components allows for the continuous variation of the fine-mode aerosol absorption. Assuming that the correct aerosol model (i.e. the correct mixing fractions of the four components) is selected during the retrieval process, also other aerosol properties could be computed such as the single scattering albedo (SSA). Implications of this assumption regarding the ratio of the weakly/strongly absorbing fine-mode fraction are investigated in this paper by evaluating the validity of the SSA thus obtained. The SSA is indirectly estimated for aerosol plumes with moderate-to-high AOD resulting from wildfires in Russia in the summer of 2010. Together with the AOD, the SSA provides the aerosol absorbing optical depth (AAOD). The results are compared with AERONET data, i.e. AOD level 2.0 and SSA and AAOD inversion products. The RMSE

  14. Single-particle characterization of the high-Arctic summertime aerosol

    Science.gov (United States)

    Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

    2014-07-01

    Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of unknown composition

  15. Study of Cl-containing urban aerosol particles by ion beam analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Angyal, A. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary); Kertesz, Zs., E-mail: zsofi@atomki.h [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szikszai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Szoboszlai, Z. [Laboratory of Ion Beam Applications (IBA LAB), Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); University of Debrecen - ATOMKI, Department of Environmental Physics, H-4001 Debrecen, P.O. Box 51 (Hungary)

    2010-06-15

    Fine (aerodynamic diameter < 2.5 {mu}m) and coarse (10 {mu}m {>=} aerodynamic diameter {>=} 2.5 {mu}m) mode urban aerosol samples were collected with 2-h time resolution in the frame of several sampling campaigns between 2007 and 2009 in downtown Debrecen, East-Hungary. The elemental composition (for Z {>=} 13) of the samples was measured by particle induced X-ray emission (PIXE). On this basis sources of urban aerosol were determined by factor analysis. For both size fractions a source characterized by high chlorine content were found. However, the origin of the Cl-containing aerosol could not be ascertained. Further investigation of samples characterized with high Cl content were done on the ATOMKI Scanning Nuclear Microprobe Facility in order to determine the possible chemical composition of these particles and thus the potential sources. Morphology, size and elemental composition for Z {>=} 6 of around 1000 coarse mode particles were determined by using STIM (Scanning Transmission Ion Microscopy), light-element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the obtained dataset in order to group the particles; correlations between different elements were also calculated. Five possible sources of Cl were identified, from which four were anthropogenic: winter salting of streets, agriculture through fertilizers, buildings and industry; the natural group was sea-salt.

  16. [Assessment of individual iodine intake by the adult population in the Potsdam region on the basis of sea fish and iodized salt consumption].

    Science.gov (United States)

    Pfaff, G; Georg, T

    1995-06-01

    Iodized salt has a high acceptance in the Potsdam region: 82% of the interviewed people use iodized salt, 13% do not use it, and only 5% of the probands were not able to make any statements. The current average iodine intake for adults is 76 micrograms/day. Only 5% of the adult population has an iodine intake of more than 100 micrograms/day. An efficient elimination of iodine deficiency in Germany requires a broad usage of iodized salt in the food industry.

  17. Development of an inorganic and organic aerosol model (CHIMERE 2017β v1.0): seasonal and spatial evaluation over Europe

    Science.gov (United States)

    Couvidat, Florian; Bessagnet, Bertrand; Garcia-Vivanco, Marta; Real, Elsa; Menut, Laurent; Colette, Augustin

    2018-01-01

    A new aerosol module was developed and integrated in the air quality model CHIMERE. Developments include the use of the Model of Emissions and Gases and Aerosols from Nature (MEGAN) 2.1 for biogenic emissions, the implementation of the inorganic thermodynamic model ISORROPIA 2.1, revision of wet deposition processes and of the algorithms of condensation/evaporation and coagulation and the implementation of the secondary organic aerosol (SOA) mechanism H2O and the thermodynamic model SOAP. Concentrations of particles over Europe were simulated by the model for the year 2013. Model concentrations were compared to the European Monitoring and Evaluation Programme (EMEP) observations and other observations available in the EBAS database to evaluate the performance of the model. Performances were determined for several components of particles (sea salt, sulfate, ammonium, nitrate, organic aerosol) with a seasonal and regional analysis of results. The model gives satisfactory performance in general. For sea salt, the model succeeds in reproducing the seasonal evolution of concentrations for western and central Europe. For sulfate, except for an overestimation of sulfate in northern Europe, modeled concentrations are close to observations and the model succeeds in reproducing the seasonal evolution of concentrations. For organic aerosol, the model reproduces with satisfactory results concentrations for stations with strong modeled biogenic SOA concentrations. However, the model strongly overestimates ammonium nitrate concentrations during late autumn (possibly due to problems in the temporal evolution of emissions) and strongly underestimates summer organic aerosol concentrations over most of the stations (especially in the northern half of Europe). This underestimation could be due to a lack of anthropogenic SOA or biogenic emissions in northern Europe. A list of recommended tests and developments to improve the model is also given.

  18. Development of an inorganic and organic aerosol model (CHIMERE 2017β v1.0: seasonal and spatial evaluation over Europe

    Directory of Open Access Journals (Sweden)

    F. Couvidat

    2018-01-01

    Full Text Available A new aerosol module was developed and integrated in the air quality model CHIMERE. Developments include the use of the Model of Emissions and Gases and Aerosols from Nature (MEGAN 2.1 for biogenic emissions, the implementation of the inorganic thermodynamic model ISORROPIA 2.1, revision of wet deposition processes and of the algorithms of condensation/evaporation and coagulation and the implementation of the secondary organic aerosol (SOA mechanism H2O and the thermodynamic model SOAP. Concentrations of particles over Europe were simulated by the model for the year 2013. Model concentrations were compared to the European Monitoring and Evaluation Programme (EMEP observations and other observations available in the EBAS database to evaluate the performance of the model. Performances were determined for several components of particles (sea salt, sulfate, ammonium, nitrate, organic aerosol with a seasonal and regional analysis of results. The model gives satisfactory performance in general. For sea salt, the model succeeds in reproducing the seasonal evolution of concentrations for western and central Europe. For sulfate, except for an overestimation of sulfate in northern Europe, modeled concentrations are close to observations and the model succeeds in reproducing the seasonal evolution of concentrations. For organic aerosol, the model reproduces with satisfactory results concentrations for stations with strong modeled biogenic SOA concentrations. However, the model strongly overestimates ammonium nitrate concentrations during late autumn (possibly due to problems in the temporal evolution of emissions and strongly underestimates summer organic aerosol concentrations over most of the stations (especially in the northern half of Europe. This underestimation could be due to a lack of anthropogenic SOA or biogenic emissions in northern Europe. A list of recommended tests and developments to improve the model is also given.

  19. Sensitivity Studies on the Influence of Aerosols on Cloud and Precipitation Development Using WRF Mesoscale Model Simulations

    Science.gov (United States)

    Thompson, G.; Eidhammer, T.; Rasmussen, R.

    2011-12-01

    Using the WRF model in simulations of shallow and deep precipitating cloud systems, we investigated the sensitivity to aerosols initiating as cloud condensation and ice nuclei. A global climatological dataset of sulfates, sea salts, and dust was used as input for a control experiment. Sensitivity experiments with significantly more polluted conditions were conducted to analyze the resulting impacts to cloud and precipitation formation. Simulations were performed using the WRF model with explicit treatment of aerosols added to the Thompson et al (2008) bulk microphysics scheme. The modified scheme achieves droplet formation using pre-tabulated CCN activation tables provided by a parcel model. The ice nucleation is parameterized as a function of dust aerosols as well as homogeneous freezing of deliquesced aerosols. The basic processes of aerosol activation and removal by wet scavenging are considered, but aerosol characteristic size or hygroscopicity does not change due to evaporating droplets. In other words, aerosol processing was ignored. Unique aspects of this study include the usage of one to four kilometer grid spacings and the direct parameterization of ice nucleation from aerosols rather than typical temperature and/or supersaturation relationships alone. Initial results from simulations of a deep winter cloud system and its interaction with significant orography show contrasting sensitivities in regions of warm rain versus mixed liquid and ice conditions. The classical view of higher precipitation amounts in relatively clean maritime clouds with fewer but larger droplets is confirmed for regions dominated by the warm-rain process. However, due to complex interactions with the ice phase and snow riming, the simulations revealed the reverse situation in high terrain areas dominated by snow reaching the surface. Results of other cloud systems will be summarized at the conference.

  20. Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece.

    Science.gov (United States)

    Paraskevopoulou, D; Liakakou, E; Gerasopoulos, E; Mihalopoulos, N

    2015-09-15

    To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Elemental composition of urban aerosol collected in Florence, Italy

    International Nuclear Information System (INIS)

    Lucarelli, F.; Mando, P.A.; Nava, S.; Prati, P.; Zucchiatti, A.

    2000-01-01

    An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. The aim is to determine the aerosol elemental concentrations as well to identify pollution sources. For our investigation, we use the external PIXE-PIGE beam facility of the Van de Graaff accelerator of INFN at the Physics Department of the Florence University. We report here an overview of the results of the PIXE analysis of a long temporal series (about 1 yr) of PM 10 particulate collected on Millipore filters on a daily basis in three different sites (characterised by different urban settings). Daily concentrations of more than 20 elements have been obtained. From the observed elemental concentrations seasonal variation were found. A relevant decrease of S, Pb and Br levels has been found with respect to 10 yr ago. Four main sources (traffic, sulphates, soil-dust and wind-transported sea-salt) have been extracted with the help of factor analysis

  2. Air-sea exchange studies at the North Sea

    NARCIS (Netherlands)

    Leeuw, G. de; Eijk, A.M.J. van; Kunz, G.J.; Veefkind, P.J.

    1996-01-01

    The North Sea can be considered as a local 'inner' sea in which many processes are quite different from these over the open ocean. The surrounding land has a major influence, being the source for man-made aerosols and gases, whereas the North Sea acts as a sink for these. At the same time the North

  3. The size distribution of marine atmospheric aerosol with regard to primary biological aerosol particles over the South Atlantic Ocean

    Science.gov (United States)

    Matthias-Maser, Sabine; Brinkmann, Jutta; Schneider, Wilhelm

    The marine atmosphere is characterized by particles which originate from the ocean and by those which reached the air by advection from the continent. The bubble-burst mechanism produces both sea salt as well as biological particles. The following article describes the determination of the size distribution of marine aerosol particles with special emphasis on the biological particles. Th data were obtained on three cruises with the German Research Vessel "METEOR" crossing the South Atlantic Ocean. The measurements showed that biological particles amount to 17% in number and 10% in volume concentration. Another type of particle became obvious in the marine atmosphere, the biologically contaminated particle, i.e. particles which consist partly (approximately up to one-third) of biological matter. Their concentration in the evaluated size class ( r>2 μm) is higher than the concentration of the pure biological particles. The concentrations vary over about one to two orders of magnitude during all cruises.

  4. SeaWiFS Deep Blue Aerosol Optical Thickness Monthly Level 3 Climatology Data Gridded at 0.5 Degrees V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS Deep Blue Level 3 Monthly Climatology Product contains monthly global climatology gridded (0.5 x 0.5 deg) data derived from SeaWiFS Deep Blue Level 3...

  5. Aerosol studies

    International Nuclear Information System (INIS)

    Cristy, G.A.; Fish, M.E.

    1978-01-01

    As part of the continuing studies of the effects of very severe reactor accidents, an effort was made to develop, test, and improve simple, effective, and inexpensive methods by which the average citizen, using only materials readily available, could protect his residence, himself, and his family from injury by toxic aerosols. The methods for protection against radioactive aerosols should be equally effective against a clandestine biological attack by terrorists. The results of the tests to date are limited to showing that spores of the harmless bacterium, bacillus globegii (BG), can be used as a simulant for the radioactive aerosols. An aerosol generator of Lauterbach type was developed which will produce an essentially monodisperse aerosol at the rate of 10 9 spores/min. Analytical techniques have been established which give reproducible results. Preliminary field tests have been conducted to check out the components of the system. Preliminary tests of protective devices, such as ordinary vacuum sweepers, have given protection factors of over 1000

  6. A six year satellite-based assessment of the regional variations in aerosol indirect effects

    Directory of Open Access Journals (Sweden)

    T. A. Jones

    2009-06-01

    Full Text Available Aerosols act as cloud condensation nuclei (CCN for cloud water droplets, and changes in aerosol concentrations have significant microphysical impacts on the corresponding cloud properties. Moderate Resolution Imaging Spectroradiometer (MODIS aerosol and cloud properties are combined with NCEP Reanalysis data for six different regions around the globe between March 2000 and December 2005 to study the effects of different aerosol, cloud, and atmospheric conditions on the aerosol indirect effect (AIE. Emphasis is placed in examining the relative importance of aerosol concentration, type, and atmospheric conditions (mainly vertical motion to AIE from region to region.

    Results show that in most regions, AIE has a distinct seasonal cycle, though the cycle varies in significance and period from region to region. In the Arabian Sea (AS, the six-year mean anthropogenic + dust AIE is −0.27 Wm−2 and is greatest during the summer months (<−2.0 Wm−2 during which aerosol concentrations (from both dust and anthropogenic sources are greatest. Comparing AIE as a function of thin (LWP<20 gm−2 vs. thick (LWP≥20 gm−2 clouds under conditions of large scale ascent or decent at 850 hPa showed that AIE is greatest for thick clouds during periods of upward vertical motion. In the Bay of Bengal, AIE is negligible owing to less favorable atmospheric conditions, a lower concentration of aerosols, and a non-alignment of aerosol and cloud layers. In the eastern North Atlantic, AIE is weakly positive (+0.1 Wm−2 with dust aerosol concentration being much greater than the anthropogenic or sea salt components. However, elevated dust in this region exists above the maritime cloud layers and does not have a hygroscopic coating, which occurs in AS, preventing the dust from acting as CCN and limiting AIE. The Western Atlantic has a large anthropogenic aerosol concentration transported from the eastern

  7. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Rosen, J.; Ivanov, V.A.

    1993-01-01

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  8. Extremely large anthropogenic-aerosol contribution to total aerosol load over the Bay of Bengal during winter season

    Directory of Open Access Journals (Sweden)

    D. G. Kaskaoutis

    2011-07-01

    Full Text Available Ship-borne observations of spectral aerosol optical depth (AOD have been carried out over the entire Bay of Bengal (BoB as part of the W-ICARB cruise campaign during the period 27 December 2008–30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD500>0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Ångström exponent is also found to be high (~1.2–1.25 indicating transport of strong anthropogenic emissions from continental regions, while very high AOD500 (0.39±0.07 and α380–870 values (1.27±0.09 are found over the eastern BoB. Except from the large α380–870 values, an indication of strong fine-mode dominance is also observed from the AOD curvature, which is negative in the vast majority of the cases, suggesting dominance of an anthropogenic-pollution aerosol type. On the other hand, clean maritime conditions are rather rare over the region, while the aerosol types are further examined through a classification scheme based on the relationship between α and dα. It was found that even for the same α values the fine-mode dominance is larger for higher AODs showing the strong continental influence over the marine environment of BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The results obtained using OPAC model show significant fraction of soot aerosols (~6 %–8 % over the eastern and northwestern BoB, while coarse-mode sea salt particles are found to dominate in the southern parts of BoB.

  9. Distinct high molecular weight organic compound (HMW-OC) types in aerosol particles collected at a coastal urban site

    Science.gov (United States)

    Dall'Osto, M.; Healy, R. M.; Wenger, J. C.; O'Dowd, C.; Ovadnevaite, J.; Ceburnis, D.; Harrison, Roy M.; Beddows, D. C. S.

    2017-12-01

    Organic oligomers were discovered in laboratory-generated atmospheric aerosol over a decade ago. However, evidence for the presence of oligomers in ambient aerosols is scarce and mechanisms for their formation have yet to be fully elucidated. In this work, three unique aerosol particle types internally mixed with High molecular weight organic compounds (HMW-OC) species - likely oligomers - were detected in ambient air using single particle Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS) in Cork (Ireland) during winter 2009. These particle types can be described as follows: (1) HMW-OCs rich in organic nitrogen - possibly containing nitrocatechols and nitroguaiacols - originating from primary emissions of biomass burning particles during evening times; (2) HMW-OCs internally mixed with nitric acid, occurring in stagnant conditions during night time; and (3) HMW-OCs internally mixed with sea salt, likely formed via photochemical reactions during day time. The study exemplifies the power of methodologies capable of monitoring the simultaneous formation of organic and inorganic particle-phase reaction products. Primary emissions and atmospheric aging of different types of HMW-OC contributes to aerosol with a range of acidity, hygroscopic and optical properties, which can have different impacts on climate and health.

  10. GEM-AQ/EC, an on-line global multi-scale chemical weather modelling system: model development and evaluation of global aerosol climatology

    Directory of Open Access Journals (Sweden)

    S. L. Gong

    2012-09-01

    Full Text Available A global air quality modeling system GEM-AQ/EC was developed by implementing tropospheric chemistry and aerosol processes on-line into the Global Environmental Multiscale weather prediction model – GEM. Due to the multi-scale features of the GEM, the integrated model, GEM-AQ/EC, is able to investigate chemical weather at scales from global to urban domains. The current chemical mechanism is comprised of 50 gas-phase species, 116 chemical and 19 photolysis reactions, and is complemented by a sectional aerosol module CAM (The Canadian Aerosol Module with 5 aerosols types: sulphate, black carbon, organic carbon, sea-salt and soil dust. Monthly emission inventories of black carbon and organic carbon from boreal and temperate vegetation fires were assembled using the most reliable areas burned datasets by countries, from statistical databases and derived from remote sensing products of 1995–2004. The model was run for ten years from from 1995–2004 with re-analyzed meteorology on a global uniform 1° × 1° horizontal resolution domain and 28 hybrid levels extending up to 10 hPa. The simulating results were compared with various observations including surface network around the globe and satellite data. Regional features of global aerosols are reasonably captured including emission, surface concentrations and aerosol optical depth. For various types of aerosols, satisfactory correlations were achieved between modeled and observed with some degree of systematic bias possibly due to large uncertainties in the emissions used in this study. A global distribution of natural aerosol contributions to the total aerosols is obtained and compared with observations.

  11. Aerosol volatility in a boreal forest environment

    Science.gov (United States)

    Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

    2012-04-01

    Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility o