WorldWideScience

Sample records for atmospheric water transport

  1. Solar geoengineering, atmospheric water vapor transport, and land plants

    Science.gov (United States)

    Caldeira, Ken; Cao, Long

    2015-04-01

    This work, using the GeoMIP database supplemented by additional simulations, discusses how solar geoengineering, as projected by the climate models, affects temperature and the hydrological cycle, and how this in turn is related to projected changes in net primary productivity (NPP). Solar geoengineering simulations typically exhibit reduced precipitation. Solar geoengineering reduces precipitation because solar geoengineering reduces evaporation. Evaporation precedes precipitation, and, globally, evaporation equals precipitation. CO2 tends to reduce evaporation through two main mechanisms: (1) CO2 tends to stabilize the atmosphere especially over the ocean, leading to a moister atmospheric boundary layer over the ocean. This moistening of the boundary layer suppresses evaporation. (2) CO2 tends to diminish evapotranspiration, at least in most land-surface models, because higher atmospheric CO2 concentrations allow leaves to close their stomata and avoid water loss. In most high-CO2 simulations, these effects of CO2 which tend to suppress evaporation are masked by the tendency of CO2-warming effect to increase evaporation. In a geoengineering simulation, with the warming effect of CO2 largely offset by the solar geoengineering, the evaporation suppressing characteristics of CO2 are no longer masked and are clearly exhibited. Decreased precipitation in solar geoengineering simulations is a bit like ocean acidification - an effect of high CO2 concentrations that is not offset by solar geoengineering. Locally, precipitation ultimately either evaporates (much of that through the leaves of plants) or runs off through groundwater to streams and rivers. On long time scales, runoff equals precipitation minus evaporation, and thus, water runoff generated at a location is equal to the net atmospheric transport of water to that location. Runoff typically occurs where there is substantial soil moisture, at least seasonally. Locations where there is enough water to maintain

  2. UTMTOX, Toxic Chemical Transport in Atmosphere, Ground Water, Sediments

    International Nuclear Information System (INIS)

    A - Description of program or function: UTMTOX is a unified transport model for toxic materials. It combines hydrologic, atmospheric, and sediment transport in one computer code and extends the scope to predict the transport of not only trace metals but also many chemical compounds, including organics. UTMTOX is capable of calculating 1) the atmospheric dispersion of up to 20 chemicals from a maximum of 10 point, 10 line, and 10 area sources; 2) deposition of one chemical at a time in both wet and dry form on foliage or the surface of the earth; 3) surface flow and erosion; 4) percolation through the soil to a stream channel; and 5) flow in the stream channel to the outfall of a watershed. B - Method of solution: UTMTOX calculates rates of flux of chemicals from release to the atmosphere, through deposition on a watershed, infiltration, and runoff from the soil to flow in the stream channel and the associated sediment transport. From these values, mass balances can be established, budgets for the chemical can be made, and concentrations in many environmental compartments can be estimated. Since the coupling is established among three major submodels, they can share data

  3. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    CERN Document Server

    Greve, Ralf; Stenzel, Oliver J

    2009-01-01

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterizations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiation balance, includes a treatment of the seasonal CO2 cap, and has been validated against the surface temperatures from the Mars Climate Database. The evaporation rate of water is calculated by an expression for free convection, driven by density differences between water vapor and ambient air, and the condensation rate follows from the assumption that any water vapour which exceeds the local saturation pressure condenses instantly. Atmospheric transport of water vapour is assumed to be purely diffusive, with an adjustable...

  4. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    OpenAIRE

    Greve, Ralf; Grieger, Bjoern; Stenzel, Oliver J.

    2009-01-01

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterisations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiati...

  5. An atmospheric radiative-convective model with interactive water vapor transport and cloud development

    OpenAIRE

    HUMMEL, JOHN R.; KUHN, WILLIAM R.

    2011-01-01

    In the present generation of radiative-convective models, clouds are assigned specific levels or temperatures that do not change during the course of the calculations. In addition, a single water vapor distribution is used for the “mean atmosphere” instead of separate distributions for the clear sky and cloudy sky atmospheres. We present results from a one-dimensional radiative-convective model that includes interactive water vapor transport and predicts cloud altitudes and thicknesses. The ...

  6. Transport of water in a transient impact-generated lunar atmosphere

    Science.gov (United States)

    Prem, P.; Artemieva, N. A.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.

    2015-07-01

    In recent decades, several missions have detected signs of water and other volatiles in cold, permanently shadowed craters near the lunar poles. Observations suggest that some of these volatiles could have been delivered by comet impacts and therefore, understanding the impact delivery mechanism becomes key to explaining the origin and distribution of lunar water. During impact, the constituent ices of a comet nucleus vaporize; a significant part of this vapor remains gravitationally bound to the Moon, transforming the tenuous, collisionless lunar exosphere into a collisionally thick, transient atmosphere. Here, we use numerical simulations to investigate the physical processes governing volatile transport in the transient atmosphere generated after a comet impact, with a focus on how these processes influence the accumulation of water in polar cold traps. It is observed that the transient atmosphere maintains a certain characteristic structure for at least several Earth days after impact, during which time volatile transport occurs primarily through low-altitude winds that sweep over the lunar day-side. Meanwhile, reconvergence of vapor antipodal to the point of impact results in preferential redistribution of water in the vicinity of the antipode. Due to the quantity of vapor that remains gravitationally bound, the atmosphere is sufficiently dense that lower layers are shielded from photodestruction, prolonging the lifetime of water molecules and allowing greater amounts of water to reach cold traps. Short-term ice deposition patterns are markedly non-uniform and the variations that arise in simulated volatile abundance between different cold traps could potentially explain variations that have been observed through remote sensing.

  7. Investigating the Source, Transport, and Isotope Composition of Water in the Atmospheric Boundary Layer

    Science.gov (United States)

    Griffis, T. J.; Schultz, N. M.; Lee, X.

    2011-12-01

    The isotope composition of water (liquid and vapor phases) can provide important insights regarding the source of water used by plants, the origins of atmospheric water vapor, and the sources of carbon dioxide. In recent years there have been significant advances in the ability to quantify the isotope composition of water and water vapor using optical isotope techniques. We have used and helped develop some of these techniques to determine the isotope composition of soil and plant waters, to measure the isoflux of water vapor between the land surface and atmosphere, and to examine the isotope composition of water vapor and deuterium excess in the atmospheric boundary layer. In this presentation we will discuss three related issues: 1) Identification and correction of spectral contamination in soil and plant water samples using optical techniques; 2) The benefits and practical limitations of quantifying the isotope composition of evapotranspiration using the eddy covariance approach; and 3) The scientific value and feasibility of tracking the long-term (seasonal and interannual) behavior of the isotope composition of water vapor and deuterium excess in the atmospheric boundary layer. A few short stories will be provided from experiments conducted in the lab, at the field scale, and from a very tall tower at the University of Minnesota from 2008 to 2011.

  8. Atmospheric water vapor transport: Estimation of continental precipitation recycling and parameterization of a simple climate model. M.S. Thesis

    Science.gov (United States)

    Brubaker, Kaye L.; Entekhabi, Dara; Eagleson, Peter S.

    1991-01-01

    The advective transport of atmospheric water vapor and its role in global hydrology and the water balance of continental regions are discussed and explored. The data set consists of ten years of global wind and humidity observations interpolated onto a regular grid by objective analysis. Atmospheric water vapor fluxes across the boundaries of selected continental regions are displayed graphically. The water vapor flux data are used to investigate the sources of continental precipitation. The total amount of water that precipitates on large continental regions is supplied by two mechanisms: (1) advection from surrounding areas external to the region; and (2) evaporation and transpiration from the land surface recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. In a separate, but related, study estimates of ocean to land water vapor transport are used to parameterize an existing simple climate model, containing both land and ocean surfaces, that is intended to mimic the dynamics of continental climates.

  9. Influence of long-range transboundary transport on atmospheric water vapor mercury collected at the largest city of Tibet.

    Science.gov (United States)

    Huang, Jie; Kang, Shichang; Tian, Lide; Guo, Junming; Zhang, Qianggong; Cong, Zhiyuan; Sillanpää, Mika; Sun, Shiwei; Tripathee, Lekhendra

    2016-10-01

    Monsoon circulation is an important process that affects long-range transboundary transport of anthropogenic contaminants such as mercury (Hg). During the Indian monsoon season of 2013, a total of 92 and 26 atmospheric water vapor samples were collected at Lhasa, the largest city of the Tibet, for Hg and major ions analysis, respectively. The relatively low pH/high electronic conductivity values, together with the fact that NH4(+) in atmospheric water vapor was even higher than that determined in precipitation of Lhasa, indicated the effects of anthropogenic perturbations through long-range transboundary atmospheric transport. Concentrations of Hg in atmospheric water vapor ranged from 2.5 to 73.7ngL(-1), with an average of 12.5ngL(-1). The elevated Hg and major ions concentrations, and electronic conductivity values were generally associated with weak acidic samples, and Hg mainly loaded with anthropogenic ions such as NH4(+). The results of principal component analysis and trajectory analysis suggested that anthropogenic emissions from the Indian subcontinent may have largely contributed to the determined Hg in atmospheric water vapor. Furthermore, our study reconfirmed that below-cloud scavenging contribution was significant for precipitation Hg in Lhasa, and evaluated that on average 74.1% of the Hg in precipitation could be accounted for by below-cloud scavenging. PMID:27265735

  10. Parameterization of ice- and water clouds and their radiation-transport properties for large-scale atmospheric models

    International Nuclear Information System (INIS)

    A model of cloud and radiation transport for large-scale atmospheric models is introduced, which besides the water phase also takes the ice phase into account. The cloud model can diagnostically determine the degree of cloud cover, liquid water and ice content by the parameters of state given by the atmospheric model. It consists of four submodels for non-convective and convective cloudiness, boundary layer clouds and ice clouds. An existing radiation model was extended for the parametrization of the radiation transport in ice clouds. Now this model allows to calculate the radiation transport in water clouds as well as in ice clouds. Liquid and solid water phases can coexist according to a simple mixture statement. The results of a sensitivity study show a strong reaction of the cloud cover degree to changes in the relative humidity. Compared with this, variations of temperature and vertical wind velocity are of minor importance. The model of radiation transport reacts most sensitively to variations of the cloud cover degree and ice content. Changes of these two factors by about 20% lead to changes in the average warming rates in the order of magnitude of 0.1 K. (orig./KW)

  11. Influence of physicochemical water characteristics in the transport of methane to the atmosphere at Rodrigo de Freitas lagoon, RJ

    Directory of Open Access Journals (Sweden)

    Plínio Carlos Alvalá

    2012-12-01

    Full Text Available The accumulation and decomposition of organic matter in water bodies can increase the potential emission of greenhouse gases to the atmosphere. In this study, in a prospective and exploratory way, we evaluated the relationship between physicochemical characteristics of water on the transport of methane to the atmosphere at Rodrigo de Freitas lagoon, RJ. In 2011, campaigns were carried out in which 200 samples were collected for analysis of superficial methane emission and 30 water samples were collected to verify the dissolution of this gas in the water column, measuring simultaneously both the physicochemical water parameters along this column. The methane flow measurements showed that this lagoon is a source methane emission to the atmosphere with an average flux of 33 ± 10 mgCH4m-2d-1. The evaluation of limnological parameters that could affect the emission flux revealed that the water depth and temperature were the most influential factors in this process. A profile analysis of methane in the water column suggests the existence of a higher concentration of this gas in the region of the sedimentary strata at the bottom of the lagoon. However, the potential emission may not reach the surface, possibly due to the decrease in the rate of vertical diffusion of methane, as a result of the increase of pressure with depth and the presence of methanotrophic bacterias that consume methane throughout the water column.

  12. Investigations of wasted heat transport from flowing water bodies to the atmosphere

    International Nuclear Information System (INIS)

    The construction, location and equipment of the Rheinhausen measuring station are described. Subjects of the examinations are the sensible and latent heat flux from the water surface, the heat radiation balance and the visibility above the river. The recording of the measuring data and the theoretical foundations of the applied measuring methods are represented. The investigated transport coefficients for evaporation and convection show the dependence of the vertical quality transport on the meteorological boundary conditions such as stratification and wind velocity. A comparison between the directly measured evaporation and the calculations based on different customary formulars gives high deviations. The results one can derive from this report with respect to the thermal loadability of rivers are restricted due to the short measuring periods (max. 1 week). For reliable statements long range measurements (years) are needed. Furthermore the Bowen Ratio validity, the behaviour of the heat transfer number α and the meaning of wasted heat ingestion in connection with visibility measurements as well as the local orographic influence on the wind field are described. (orig.)

  13. Development of coupled models for regional water cycle and material transport in the atmospheric, terrestrial, and oceanic environment

    International Nuclear Information System (INIS)

    Numerical simulations are the effective approach to investigate the complex mechanism in environmental phenomena and many numerical models have been developed for specific applications over wide range of field. Recently, much effort has been made to develop numerical models that can deal with the multi-physics problems in the complex environmental system. Most of these models are constructed by coupling existing models developed separately for their specific field of studies and called as coupled models. A general-purpose model coupling program of Japan Atomic Energy Agency (JAEA-Coupler) has been developed to construct local to regional scale coupled models for environmental studies. In these coupled models, calculations of component models are carried out by different processors of parallel computers in the same manner as their original stand-alone calculations and the coupler controls these processes and handles data exchanges among component models using Message Passing Interface (MPI). Data exchanges are only conducted between the coupler and each component model and the coupler handles the data distribution to target models with interfacing spatial, temporal, and physical discrepancies among component models. By using JAEA-Coupler, integrated coupled models to simulate regional water cycle and material transport have been constructed. The coupled model for regional water cycle consists of the non-hydrostatic atmospheric dynamic model of PSU/NCAR (MM5), detailed multi-layer land surface model (SOLVEG) and three-dimensional hydrology model (RIVERS) developed at JAEA, the third-generation ocean wind-wave model of NOAA (WW3), and the Princeton Ocean Model (POM). For the material transport, Lagrangian particle dispersion models for the atmosphere and ocean (GEARN and SEA-GEARN, respectively) developed at JAEA are incorporated into the water cycle coupled model, where RIVERS includes the function to calculate material transport. Test calculations were carried out

  14. Atmospheric water vapor transport and recycling in Equatorial Central Africa through NCEP/NCAR reanalysis data

    Energy Technology Data Exchange (ETDEWEB)

    Pokam, Wilfried M.; Djiotang, Lucie A.T.; Mkankam, Francois K. [University of Yaounde 1, Laboratory for Environmental Modelling and Atmospheric Physics, Department of Physics, Faculty of Sciences, P.O. Box 812, Yaounde (Cameroon)

    2012-05-15

    The characteristics of the main components of the water cycle over Equatorial Central Africa (ECA) were analysed using the 32-year period, spanning from 1968 to 2000, of the National Centers for Environmental Prediction-National Censearch (NCEP-) reanalysis project database. A special emphasis was given to identifying the causes of annual and interannual variability of water vapor flux and precipitation recycling. The results suggest that the first maximum of moisture convergence, during the rainy season MAM, comes from upper level moisture flux, related to the north component of the African Easterly Jet (AEJ-N). The second, and greatest, maximum in SON is found to be a consequence of low level moisture advection from the Atlantic Ocean. AEJ-N also drive the seasonal spatial pattern of moisture flux. The interannual variability of moisture flux is contributed mainly by the low level moisture advected from the Atlantic Ocean, underlying its crucial role for the regional climate. Studying the recycling ratio in ECA as a whole shows a low annual cycle whereas subregional scale analysis reveals high amplitude of the seasonal variation. Seasonal variability of the spatial gradient of precipitation recycling is regulated by both moisture flux direction and strength. The annual cycles of recycling ratio in the North and the South of ECA are regulated by both moisture transport and evapotranspiration. (orig.)

  15. Lateral transport of soil carbon and land‑atmosphere CO2 flux induced by water erosion in China

    Science.gov (United States)

    Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G. L.; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

    2016-06-01

    Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land‑atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt Cṡy‑1 of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt Cṡy‑1, equivalent to 8–37% of the terrestrial carbon sink previously assessed in China. Interestingly, the “hotspots,” largely distributed in mountainous regions in the most intensive sink areas (>40 g Cṡm‑2ṡy‑1), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty.

  16. Lateral transport of soil carbon and land−atmosphere CO2 flux induced by water erosion in China

    Science.gov (United States)

    Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G. L.; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

    2016-01-01

    Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land−atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C⋅y−1 of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt C⋅y−1, equivalent to 8–37% of the terrestrial carbon sink previously assessed in China. Interestingly, the “hotspots,” largely distributed in mountainous regions in the most intensive sink areas (>40 g C⋅m−2⋅y−1), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty. PMID:27247397

  17. Lateral transport of soil carbon and land-atmosphere CO2 flux induced by water erosion in China.

    Science.gov (United States)

    Yue, Yao; Ni, Jinren; Ciais, Philippe; Piao, Shilong; Wang, Tao; Huang, Mengtian; Borthwick, Alistair G L; Li, Tianhong; Wang, Yichu; Chappell, Adrian; Van Oost, Kristof

    2016-06-14

    Soil erosion by water impacts soil organic carbon stocks and alters CO2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land-atmosphere CO2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C⋅y(-1) of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO2 of 45 ± 25 Mt C⋅y(-1), equivalent to 8-37% of the terrestrial carbon sink previously assessed in China. Interestingly, the "hotspots," largely distributed in mountainous regions in the most intensive sink areas (>40 g C⋅m(-2)⋅y(-1)), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO2 sink. The erosion-induced CO2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO2 in the terrestrial budget, hence reducing the level of uncertainty. PMID:27247397

  18. Atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    The chairman and contributors are members of the Working Group on Atmospheric Dispersion, Deposition, and Resuspension. This group examined the mathematical approaches for determining the direct and indirect pathways to man of releases of pollutants to the atmosphere. The dose-to-man limitations promulgated by the Nuclear Regulatory Commission, the Environmental Protection Agency, and the Energy Research and Development Administration were presented. The present status of research was discussed, and recommendations for future work were made. Particular emphasis was placed on the need for additional experimental work to develop confidence limits leading to acceptable probability statements of critical pathways for determining the dose-to-man

  19. Water-transporting proteins.

    Science.gov (United States)

    Zeuthen, Thomas

    2010-04-01

    Transport through lipids and aquaporins is osmotic and entirely driven by the difference in osmotic pressure. Water transport in cotransporters and uniporters is different: Water can be cotransported, energized by coupling to the substrate flux by a mechanism closely associated with protein. In the K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water is not clear. It is associated with the substrate movements in aqueous pathways within the protein; a conventional unstirred layer mechanism can be ruled out, due to high rates of diffusion in the cytoplasm. The physiological roles of the various modes of water transport are reviewed in relation to epithelial transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity of the transportate to approach isotonicity. PMID:20091162

  20. Hydrologic, Water-Quality, Sediment Transport, and Bulk Atmospheric-Deposition Data, Guanella Pass Area, Colorado, October 1, 1994, through September 30, 1997

    Science.gov (United States)

    Stevens, Michael R.

    2000-01-01

    The hydrology and water quality of streams and lakes in the Guanella Pass area could be affected by the proposed reconstruction of the existing road over Guanella Pass between Georgetown and Grant, Colo. Data were collected during water years 1995 through 1997 (October 1, 1994, through September 30, 1997) that describe the preconstruction hydrology, water quality, sediment transport, and bulk atmospheric deposition in the Guanella Pass study area with most data being collected primarily during water years 1996-97. Data were collected at 17 stream sites, 7 road-runoff sites, 10 ground-water sites, 3 lake sites, 1 reservoir site, 2 snow-precipitation sites, and 4 bulk atmospheric-deposition sites. Data include onsite measurements of streamflow, specific conductance, pH, water temperature, turbidity, barometric pressure, and dissolved oxygen; concentrations of major ions, nutrients, and trace elements; organic carbon and trace organic compounds; suspended-sediment concentration and particle-size analyses; field measurement and depth profiles, and chlorophyll concentrations in lakes and reservoirs; trace element, nutrient, and trace organic (semi-volatiles, PCBs, and insecticides) analyses of lake and reservoir bottom sediment; and bulk atmospheric deposition rates of solids. Daily values for streamflow, maximum and minimum water temperature, specific conductance, and suspended sediment were computed at seven streamflow-monitoring stations located along South Clear Creek, Leavenworth Creek, Duck Creek, Geneva Creek, and Deer Creek.

  1. ATMOSPHERIC TRANSPORT AND DEPOSITION OF AGRICULTURAL PESTICIDES TO SENSITIVE ECOSYSTEMS

    Science.gov (United States)

    Off-site transport of pesticides from the point of application may occur by runoff to surface waters, leaching into sub-soil layers and groundwater, and via volatilization to the atmosphere. Atmospheric transport and subsequent deposition of pesticides may negatively affect sensitive wildlife speci...

  2. Water flow and solute transport in the soil-plant-atmosphere continuum: Upscaling from rhizosphere to root zone

    Science.gov (United States)

    Lazarovitch, Naftali; Perelman, Adi; Guerra, Helena; Vanderborght, Jan; Pohlmeier, Andreas

    2016-04-01

    Root water and nutrient uptake are among the most important processes considered in numerical models simulating water content and fluxes in the subsurface, as they control plant growth and production as well as water flow and nutrient transport out of the root zone. Root water uptake may lead to salt accumulation at the root-soil interface, resulting in rhizophere salt concentrations much higher than in the bulk soil. This salt accumulation is caused by soluble salt transport towards the roots by mass flow through the soil, followed by preferential adsorption of specific nutrients by active uptake, thereby excluding most other salts at the root-soil interface or in the root apoplast. The salinity buildup can lead to large osmotic pressure gradients across the roots thereby effectively reducing root water uptake. The initial results from rhizoslides (capillary paper growth system) show that sodium concentration is decreasing with distance from the root, compared with the bulk that remained more stable. When transpiration rate was decreased under high salinity levels, sodium concentration was more homogenous compared with low salinity levels. Additionally, sodium and gadolinium distributions were measured nondestructively around tomato roots using magnetic resonance imaging (MRI). This technique could also observe the root structure and water content around single roots. Results from the MRI confirm the solutes concentration pattern around roots and its relation to their initial concentration. We conclude that local water potentials at the soil-root interface differ from bulk potentials. These relative differences increase with decreasing root density, decreasing initial salt concentration and increasing transpiration rate. Furthermore, since climate may significantly influence plant response to salinity a dynamic climate-coupled salinity reduction functions are critical in while using macroscopic numerical models.

  3. Water-transporting proteins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas

    2010-01-01

    K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water is not...... clear. It is associated with the substrate movements in aqueous pathways within the protein; a conventional unstirred layer mechanism can be ruled out, due to high rates of diffusion in the cytoplasm. The physiological roles of the various modes of water transport are reviewed in relation to epithelial...... transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support to...

  4. Instructional guidelines on sampling of water, atmospheric precipitations, sewage and other liquids, their packing, marking, transportation, preparation to investigations and storage

    International Nuclear Information System (INIS)

    Instructional guidelines was elaborated in the frame of International Scientific Technic Centre project T-1082.3 and directed on arrangement of radiation environment investigations on the territory of the Republic waste disposal site. Instructional guidelines put requirements on sampling of water, atmospheric precipitations, sewage and other liquids, their packing, marking, transportation, preparation of samples to investigation and storage of samples in laboratory conditions. The aim of investigations is revelation of polluted objects on the territory of the Republic waste disposal site, determination of pollution intensity level, pollution dynamics, determination of pollution impact and elaboration measures in order to eliminate their harmful effect on human body and environment.

  5. Modelling Ballast Water Transport

    Digital Repository Service at National Institute of Oceanography (India)

    Jayakumar, S.; Babu, M.T.; Vethamony, P.

    Ballast water discharges in the coastal environs have caused a great concern over the recent periods as they account for transporting marine organisms from one part of the world to the other. The movement of discharged ballast water as well...

  6. Water transport in brain:

    DEFF Research Database (Denmark)

    MacAulay, Nanna; Hamann, Steffan; Zeuthen, Thomas

    2004-01-01

    It is generally accepted that cotransporters transport water in addition to their normal substrates, although the precise mechanism is debated; both active and passive modes of transport have been suggested. The magnitude of the water flux mediated by cotransporters may well be significant: both...... the number of cotransporters per cell and the unit water permeability are high. For example, the Na(+)-glutamate cotransporter (EAAT1) has a unit water permeability one tenth of that of aquaporin (AQP) 1. Cotransporters are widely distributed in the brain and participate in several vital functions: inorganic......(+)-lactate cotransporters. We have previously determined water transport capacities for these cotransporters in model systems (Xenopus oocytes, cell cultures, and in vitro preparations), and will discuss their role in water homeostasis of the astroglial cell under both normo- and pathophysiologal situations. Astroglia...

  7. Atmospheric & Oceanic Applications of Eulerian and Lagrangian Transport Modelling

    OpenAIRE

    Kjellsson, Joakim

    2014-01-01

    This thesis presents several ways to understand transports of air and water masses in the atmosphere and ocean, and the transports of energy that they imply. It presents work using various kinds of observations as well as computer simulations of the atmosphere and oceans. One of the main focuses is to identify similarities and differences between models and observations, as well as between different models. The first half of the thesis applies Lagrangian methods to study flows in the atmosphe...

  8. Terrestrial atmosphere, water and astrobiology

    Directory of Open Access Journals (Sweden)

    Coradini M.

    2010-12-01

    Full Text Available Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bonds. The carbon-based molecules were either home made in the atmosphere and/or in submarine hydrothermal systems or delivered by meteorites and micrometeorites. The search for possible places beyond the earth where the trilogy atmosphere/water/life could exist is the main objective of astrobiology. Within the Solar System, exploration missions are dedicated to Mars, Europa, Titan and the icy bodies. The discovery of several hundreds of extrasolar planets opens the quest to the whole Milky Way.

  9. Modeling stomatal conductance in the Earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

    Directory of Open Access Journals (Sweden)

    G. B. Bonan

    2014-05-01

    Full Text Available The empirical Ball–Berry stomatal conductance model is commonly used in Earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs on vapor pressure deficit (Ds and soil moisture must both be empirically parameterized. We evaluated the Ball–Berry model used in the Community Land Model version 4.5 (CLM4.5 and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil–plant–atmosphere continuum (SPA to numerically optimize photosynthetic carbon gain per unit water loss while preventing leaf water potential dropping below a critical minimum level. We evaluated two alternative optimization algorithms: intrinsic water-use efficiency (Δ An/Δ gs, the marginal carbon gain of stomatal opening and water-use efficiency (Δ An/Δ El, the marginal carbon gain of water loss. We implemented the stomatal models in a multi-layer plant canopy model, to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using: (1 leaf analyses; (2 canopy net radiation, sensible heat flux, latent heat flux, and gross primary production at six AmeriFlux sites spanning 51 site–years; and (3 parameter sensitivity analyses. Without soil moisture stress, the performance of the SPA stomatal conductance model was generally comparable to or somewhat better than the Ball–Berry model in flux tower simulations, but was significantly better than the Ball–Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from the physiological theory linking leaf water-use efficiency and water flow to and from the leaf along the soil-to-leaf pathway rather than being imposed a priori, as in the Ball–Berry model. Similar functional dependence of gs on Ds emerged from the water-use efficiency optimization. Sensitivity analyses showed that two

  10. Monitoring and modeling of water flow and solute transport in the soil-plant-atmosphere system of poplar trees to evaluate the effectiveness of phytoremediation techniques.

    Science.gov (United States)

    Palladino, Mario; Di Fiore, Paola; Speranza, Giuseppe; Sica, Benedetto; Romano, Nunzio

    2015-04-01

    This work is part of a series of studies being carried out within the EU-Life+ project ECOREMED (Implementation of eco-compatible protocols for agricultural soil remediation in Litorale Domizio-Agro Aversano NIPS). The project refers to Litorale Domitio-Agro Aversano that has been identified as National Interest Priority Site (NIPS) and includes some polluted agricultural land belonging to more than 61 municipalities in the Naples and Caserta provinces of the Campania Region. The major aim of the project is to define an operating protocol for agriculture-based bioremediation of contaminated agricultural soils, also including the use of plant extracting pollutants to be used as biomasses for renewable energy production. This contribution specifically address the question of evaluating the effectiveness of phytoremediation actions selected by the project in the pilot area of Trentola-Ducenta and will provide some preliminary results of monitoring and modeling activities. A physical and hydraulic characterization has been carried out in this area where poplar trees were planted. Monitoring of water flow, root water uptake and solute transport in the soil-plant-atmosphere is under way with reference to two trees using capacitance soil moisture and matric potential sensors located at three different soil depths, whereas plant water status and evapotranspiration fluxes are indirectly estimated using fast-responding stem dendrometers.

  11. Terrestrial atmosphere, water and astrobiology

    OpenAIRE

    Coradini M.; Brack A.

    2010-01-01

    Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bon...

  12. Heat and Water Transport in Soils and Across the Soil-Atmosphere Interface: Comparison of Model Concepts

    DEFF Research Database (Denmark)

    Vanderborght, Jan; Smits, Kathleen; Mosthaf, Klaus;

    soil water content. Vapor flow influences the shape of the moisture front close to the soil surface. Simulated evaporation fluxes under dynamic forcing, e.g. due to diurnal variations in net radiation, differed considerably between the models. Experimental methods that allow monitoring of diurnal...

  13. Fission product transport in the atmosphere

    International Nuclear Information System (INIS)

    In the present thesis,a theoretical treatment has been developed for investigating the fission product transport in the atmosphere, and expressing its underlying dynamics. Some basic material has been critically reviewed for the purpose of establishing the mathematical equations that govern the motion of a general pollutant - whether it is radioactive or not - in the atmosphere. Such review included the study of particulate matter motion in the atmosphere and radioactive cloud motion, together with the analysis of available mathematical models for atmospheric dispersion

  14. Water intensity of transportation.

    Science.gov (United States)

    King, Carey W; Webber, Michael E

    2008-11-01

    As the need for alternative transportation fuels increases, it is important to understand the many effects of introducing fuels based upon feedstocks other than petroleum. Water intensity in "gallons of water per mile traveled" is one method to measure these effects on the consumer level. In this paper we investigate the water intensity for light duty vehicle (LDV) travel using selected fuels based upon petroleum, natural gas, unconventional fossil fuels, hydrogen, electricity, and two biofuels (ethanol from corn and biodiesel from soy). Fuels more directly derived from fossil fuels are less water intensive than those derived either indirectly from fossil fuels (e.g., through electricity generation) or directly from biomass. The lowest water consumptive (electric power generation) withdraw 5-20 times and consume nearly 2-5 times more water than by using petroleum gasoline. The water intensities (gal H20/mile) of LDVs operating on biofuels derived from crops irrigated in the United States at average rates is 28 and 36 for corn ethanol (E85) for consumption and withdrawal, respectively. For soy-derived biodiesel the average consumption and withdrawal rates are 8 and 10 gal H2O/mile. PMID:19031873

  15. Transport properties in the Jovian atmosphere

    Science.gov (United States)

    Biolsi, L.

    1978-01-01

    Transport properties in a Jupiter-like atmosphere (89 mol % hydrogen and 11 mol % helium) are obtained by using the method of the kinetic theory of gases. The transport collision integrals are calculated by fitting various two-body semiempirical interaction potentials for which the collision integrals are tabulated to ab initio quantum mechanical calculations of the two-body interactions. The collision integrals are used to calculate the binary diffusion coefficients, viscosity, and 'total' thermal conductivity of the pure gases and the gas mixtures at 1-atm pressure from 1000 K to 25,000 K.

  16. Transport impacts on atmosphere and climate: Land transport

    Science.gov (United States)

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

    2010-12-01

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

  17. Regional transport model of atmospheric sulfates

    International Nuclear Information System (INIS)

    As part of the Sulfate Regional Experiment (SURE) Design Project, a regional transport model of atmospheric sulfates has been developed. This quasi-Lagrangian three-dimensional grid numerical model uses a detailed SO2 emission inventory of major anthropogenic sources in the Eastern U.S. region, and observed meteorological data during an episode as inputs. The model accounts for advective transport and turbulent diffusion of the pollutants. The chemical transformation of SO2 and SO4/sup =/ and the deposition of the species at the earth's surface are assumed to be linear processes at specified constant rates. The numerical model can predict the daily average concentrations of SO2 and SO4/sup =/ at all receptor locations in the grid region during the episode. Because of the spatial resolution of the grid, this model is particularly suited to investigate the effect of tall stacks in reducing the ambient concentration levels of sulfur pollutants. This paper presents the formulations and assumptions of the regional sulfate transport model. The model inputs and results are discussed. Isopleths of predicted SO2 and SO4/sup =/ concentrations are compared with the observed ground level values. The bulk of the information in this paper is directed to air pollution meteorologists and environmental engineers interested in the atmospheric transport modeling studies of sulfur oxide pollutants

  18. Osmotic water transport in aquaporins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Alsterfjord, Magnus; Beitz, Eric;

    2013-01-01

    molecules give rise to no water transport. Accordingly, the rate of water transport is proportional to the reflection coefficient σ, while the solute permeability, P(S), is proportional to 1 - σ. The model was tested in aquaporins heterologously expressed in Xenopus oocytes. A variety of aquaporin channel...... sizes and geometries were obtained with the two aquaporins AQP1 and AQP9 and mutant versions of these. Osmotic water transport was generated by adding 20 mM of a range of different-sized osmolytes to the outer solution. The osmotic water permeability and the reflection coefficient were measured......Abstract  We test a novel, stochastic model of osmotic water transport in aquaporins. A solute molecule present at the pore mouth can either be reflected or permeate the pore. We assume that only reflected solute molecules induce osmotic transport of water through the pore, while permeating solute...

  19. Turbulent transport in the atmospheric surface layer

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Science, Lund Univ., Lund (Sweden)

    2012-04-15

    In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to {approx}3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect

  20. Conversion of elemental iodine during atmospheric transport

    International Nuclear Information System (INIS)

    At the Juelich Nuclear Research Centre the conversion of elemental iodine during the transport in the atmosphere from the source point to the place of deposition is studied. For this reason the short living I-123 is released in form of elemental iodine in 50 m release height. In a distance of 200 to 1000 m downwind air samples are taken with a tripartite filter system. Each part of the filter system is measured with a Ge(Li) detector seperately at the end of sampling. After the evaluation of the experiments until now in the average about 50% of the elemental iodine is transformed into other iodine species. (orig./HP)

  1. Middle Atmosphere Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  2. Middle Atmospheric Transport Properties of Assimilated Datasets

    Science.gov (United States)

    Pawson, Steven; Rood, Richard

    1999-01-01

    One of the most compelling reasons for performing data assimilation in the middle atmosphere is to obtain global, balanced datasets for studies of trace gas transport and chemistry. This is a major motivation behind the Goddard Earth observation System-Data Assimilation System (GEOS-DAS). Previous studies have shown that while this and other data assimilation systems can generally obtain good estimates of the extratropical rotational velocity field, the divergent part of the dynamical field is deficient; this impacts the "residual circulation" and leads to spurious trace gas transport on seasonal and interannual timescales. These problems are impacted by the quality and the method of use of the observational data and by deficiencies in the atmospheric general circulation model. Whichever the cause at any place and time, the "solution" is to introduce non-physical forcing terms into the system (the so-called incremental analysis updates); these can directly (thermal) or indirectly (mechanical) affect the residual circulation. This paper will illustrate how the divergent circulation is affected by deficiencies in both observations and models. Theoretical considerations will be illustrated with examples from the GEOS-DAS and from simplified numerical experiments. These are designed to isolate known problems, such as the inability of models to sustain a quasi-biennial oscillation and sparse observational constraints on tropical dynamics, or radiative inconsistencies in the presence of volcanic aerosols.

  3. Effect of Atmospheric Ions on Interfacial Water

    OpenAIRE

    Chien-Chang Kurt Kung; Pollack, Gerald H.

    2014-01-01

    The effect of atmospheric positivity on the electrical properties of interfacial water was explored. Interfacial, or exclusion zone (EZ) water was created in the standard way, next to a sheet of Nafion placed horizontally at the bottom of a water-filled chamber. Positive atmospheric ions were created from a high voltage source placed above the chamber. Electrical potential distribution in the interfacial water was measured using microelectrodes. We found that beyond a threshold, the positive ...

  4. Students' Conceptions of Water Transport

    Science.gov (United States)

    Rundgren, Carl-Johan; Rundgren, Shu-Nu Chang; Schonborn, Konrad J.

    2010-01-01

    Understanding diffusion of water into and out of the cell through osmosis is fundamental to the learning and teaching of biology. Although this process is thought of as occurring directly across the lipid bilayer, the majority of water transport is actually mediated by specialised transmembrane water-channels called aquaporins. This study…

  5. EDITORIAL: The global atmospheric water cycle

    Science.gov (United States)

    Bengtsson, Lennart

    2010-06-01

    Water vapour plays a key role in the Earth's energy balance. Almost 50% of the absorbed solar radiation at the surface is used to cool the surface, through evaporation, and warm the atmosphere, through release of latent heat. Latent heat is the single largest factor in warming the atmosphere and in transporting heat from low to high latitudes. Water vapour is also the dominant greenhouse gas and contributes to a warming of the climate system by some 24°C (Kondratev 1972). However, water vapour is a passive component in the troposphere as it is uniquely determined by temperature and should therefore be seen as a part of the climate feedback system. In this short overview, we will first describe the water on planet Earth and the role of the hydrological cycle: the way water vapour is transported between oceans and continents and the return of water via rivers to the oceans. Generally water vapour is well observed and analysed; however, there are considerable obstacles to observing precipitation, in particular over the oceans. The response of the hydrological cycle to global warming is far reaching. Because different physical processes control the change in water vapour and evaporation/precipitation, this leads to a more extreme distribution of precipitation making, in general, wet areas wetter and dry areas dryer. Another consequence is a transition towards more intense precipitation. It is to be expected that the changes in the hydrological cycle as a consequence of climate warming may be more severe that the temperature changes. Water on planet Earth The total amount of available water on the Earth amounts to some 1.5 x 109 km3. The dominant part of this, 1.4 x 109 km3, resides in the oceans. About 29 x 106 km3 are locked up in land ice and glaciers and some 15 x 106 km3 are estimated to exist as groundwater. If all land ice and glaciers were to melt the sea level would rise some 80 m (Baumgartner and Reichel 1975). 13 x 103 km3 of water vapour are found in the

  6. On the hydroclimate of southern South America: Water vapor transport and the role of shallow groundwater on land-atmosphere interactions

    Science.gov (United States)

    Martinez Agudelo, John Alejandro

    The present work focuses on the sources and transport of water vapor to the La Plata Basin (LPB), and the role of groundwater dynamics on the simulation of hydrometeorological conditions over the basin. In the first part of the study an extension to the Dynamic Recycling Model (DRM) is developed to estimate the water vapor transported to the LPB from different regions in South America and the nearby oceans, and the corresponding contribution to precipitation over the LPB. It is found that more than 23% of the precipitation over the LPB is from local origin, while nearly 20% originates from evapotranspiration from the southern Amazon. Most of the moisture comes from terrestrial sources, with the South American continent contributing more than 62% of the moisture for precipitation over the LPB. The Amazonian contribution increases during the positive phase of El Nino and the negative phase of the Antarctic Oscillation. In the second part of the study the effect of a groundwater scheme on the simulation of terrestrial water storage, soil moisture and evapotranspiration (ET) over the LPB is investigated. It is found that the groundwater scheme improves the simulation of fluctuations in the terrestrial water storage over parts of the southern Amazon. There is also an increase in the soil moisture in the root zone over those regions where the water table is closer to the surface, including parts of the western and southern Amazon, and of the central and southern LPB. ET increases in the central and southern LPB, where it is water limited. Over parts of the southeastern Amazon the effects of the groundwater scheme are only observed at higher resolution, when the convergence of lateral groundwater flow in local topographical depressions is resolved by the model. Finally, the effects of the groundwater scheme on near surface conditions and precipitation are explored. It is found that the increase in ET induced by the groundwater scheme over parts of the LPB induces an

  7. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line...

  8. Diffusion impact on atmospheric moisture transport

    Science.gov (United States)

    Moseley, C.; Haerter, J.; Göttel, H.; Hagemann, S.; Jacob, D.

    2009-04-01

    To ensure numerical stability, many global and regional climate models employ numerical diffusion to dampen short wavelength modes. Terrain following sigma diffusion is known to cause unphysical effects near the surface in orographically structured regions. They can be reduced by applying z-diffusion on geopotential height levels. We investigate the effect of the diffusion scheme on atmospheric moisture transport and precipitation formation at different resolutions in the European region. With respect to a better understanding of diffusion in current and future grid-space global models, current day regional models may serve as the appropriate tool for studies of the impact of diffusion schemes: Results can easily be constrained to a small test region and checked against reliable observations, which often are unavailable on a global scale. Special attention is drawn to the Alps - a region of strong topographic gradients and good observational coverage. Our study is further motivated by the appearance of the "summer drying problem" in South Eastern Europe. This too warm and too dry simulation of climate is common to many regional climate models and also to some global climate models, and remains a permanent unsolved problem in the community. We perform a systematic comparison of the two diffusion-schemes with respect to the hydrological cycle. In particular, we investigate how local meteorological quantities - such as the atmospheric moisture in the region east of the Alps - depend on the spatial model resolution. Higher model resolution would lead to a more accurate representation of the topography and entail larger gradients in the Alps. This could lead to consecutively stronger transport of moisture along the slopes in the case of sigma-diffusion with subsequent orographic precipitation, whereas the effect could be qualitatively different in the case of z-diffusion. For our study, we analyse a sequence of simulations of the regional climate model REMO employing

  9. Isotopes in the Arctic atmospheric water cycle

    OpenAIRE

    Bonne, Jean-Louis; Werner, Martin; Meyer, Hanno; Kipfstuhl, Sepp; Rabe, Benjamin; Behrens, Melanie; Schönicke, Lutz; Steen-Larsen, Hans Christian; Masson-Delmotte, Valérie

    2016-01-01

    The ISO-ARC project aims at documenting the Arctic atmospheric hydrological cycle, by assessing the imprint of the marine boundary conditions (e.g. temperature variations, circulation changes, or meltwater input) to the isotopic composition of the atmospheric water cycle (H218O and HDO) with a focus on North Atlantic and Arctic oceans. For this purpose, two continuous monitoring water vapour stable isotopes cavity ring-down spectrometers have been installed in July 2015: on-boar...

  10. Mercury-cycling in surface waters and in the atmosphere - species analysis for the investigation of transformation and transport properties of mercury

    International Nuclear Information System (INIS)

    The river Elbe has been one of the most contaminated rivers with regard to mercury for many years. In 1991 a length-profile has been measured for mercury and methylmercury (CH3Hg+) from Obristvi, Czech Republic, to the German bight. Total mercury has been measured by cold vapor atomic absorption spectrometry (CVAAS). The organo mercury compounds have been separated by high performance liquid chromatography (HPLC) connected on-line to an atomic fluorescence spectrometer (AFS) by a continuous flow-system. Total mercury up to 120 mg Hg+/kg and CH3Hg+ concentrations up to 130 μg CH3Hg+/kg could be detected in special sites. The formation of CH3Hg+ in sediments can be caused besides the methylation of mercury, by sulphate reducing or methanogenic bacteria and transmethylation reactions with organometals. Atmospheric mercury concentrations have been measured at three different European sites. Samples have been collected on gold-coated glass balls or on quartz wool, respectively. After thermal desorption mercury has been determined using the two step amalgamation technique with AFS detection. Compared to natural background concentrations of total gaseous mercury (TGM), slightly increased levels could be detected at a rural site in Germany. This increase can probably be explained by long-range transport processes. Within the vicinity of a inactivated mercury production plant high concentrations of up to 13.5 ng/m3 particle associated mercury (Hgpart) have been detected. Consequently, dry deposition of mercury in the particulate form can intensify the total deposition flux close to Hg-emitting sources. (orig.)

  11. Atmospheric emissions from road transportation in India

    International Nuclear Information System (INIS)

    India has become one of the biggest emitters of atmospheric pollutants from the road transportation sector globally. Here we present an up-to-date inventory of the exhaust emissions of ten species. This inventory has been calculated bottom-up from the vehicle mileage, differentiating by seven vehicle categories, four age/technology layers and three fuel types each, for the seven biggest cities as well as for the whole nation. The age composition of the rolling fleet has been carefully modelled, deducting about one quarter of vehicles still registered but actually out-of-service. The vehicle mileage is calibrated to the national fuel consumption which is essential to limit uncertainties. Sensitivity analyses reveal the primary impact of the emission factors and the secondary influence of vehicle mileage and stock composition on total emissions. Emission estimates since 1980 are reviewed and qualified. A more comprehensive inspection and maintenance is essential to limit pollutant emissions; this must properly include commercial vehicles. They are also the most important vehicle category to address when fuel consumption and CO2 emissions shall be contained. (author)

  12. Perspective: Water cluster mediated atmospheric chemistry

    International Nuclear Information System (INIS)

    The importance of water in atmospheric and environmental chemistry initiated recent studies with results documenting catalysis, suppression and anti-catalysis of thermal and photochemical reactions due to hydrogen bonding of reagents with water. Water, even one water molecule in binary complexes, has been shown by quantum chemistry to stabilize the transition state and lower its energy. However, new results underscore the need to evaluate the relative competing rates between reaction and dissipation to elucidate the role of water in chemistry. Water clusters have been used successfully as models for reactions in gas-phase, in aqueous condensed phases and at aqueous surfaces. Opportunities for experimental and theoretical chemical physics to make fundamental new discoveries abound. Work in this field is timely given the importance of water in atmospheric and environmental chemistry.

  13. Water transport in desert alluvial soil

    International Nuclear Information System (INIS)

    Safe storage of radioactive waste buried in an arid alluvial soil requires extensive site characterization of the physical process influencing moisture movement which could act as a transport medium for the migration of radionuclides. The field portion of this study included an infiltration plot instrumented with thermocouple psychrometers and neturon moisture probe access holes. Baseline information shows a zone of higher moisture content at approximately 1.5 m (5 ft) in depth. A sprinkler system simulated a 500-year precipitation event. Results revealed water penetrated the soil to 0.9 m (2.9 ft). Due to the low moisture content, vapor transport was primarily responsible for water movement at this depth. Temperature gradients are substantially responsible for vapor transport by preferentially sorting water-vapor molecules from the surrounding air by using the soil as a molecular sieve. Adsorbed and capillary water vapor pressure increases in response to a temperature increase and releases additional water to the soil pore atmosphere to be diffused away

  14. Global thermohaline circulation. Part II: Sensitivity with interactive atmospheric transports

    OpenAIRE

    Wang, X.; Stone, P.; Marotzke, J.

    1999-01-01

    A hybrid coupled ocean-atmosphere model is used to investigate the stability of the thermohaline circulation (THC) to an increase in the surface freshwater forcing in the presence of interactive meridional transports in the atmosphere. The ocean component is the idealized global general circulation model used in Part I. The atmospheric model assumes fixed latitudinal structure of the heat and moisture transports, and the amplitudes are calculated separately for each hemisphere from the large-...

  15. Gravitational Condensation of Atmospheric Water Vapor

    OpenAIRE

    De Aquino, Fran

    2015-01-01

    Devices that collect water from the atmospheric air using condensation are well-known. They operate in a manner very similar to that of a dehumidifier: air is passed through a cooled coil, making water to condense. This is the most common technology in use. Here, we present a device that can collect a large amount of water (more than 1m 3 /s) from the atmospheric air using gravitational condensation. Another novelty of this device is that it consumes little electricity. In addition, the new t...

  16. Water dimer and the atmospheric continuum

    International Nuclear Information System (INIS)

    The physical origin of humidity-related atmospheric continuum absorption is examined. The existence of double water molecules (dimers) in equilibrium water vapor at room temperature is proved by direct spectroscopic experiments supported by ab initio calculations. It is demonstrated that diluting water vapor with air does not significantly reduce the abundance of dimers. Numerous previous studies have predicted the presence of water dimers in the atmosphere and their influence on chemical reactions, homogeneous condensation, and Earth's radiation balance. Our results provide experimental proof of the presence of dimers in the atmosphere, thus enabling a detailed study of their role in natural processes. Prospects for future research are discussed. (reviews of topical problems)

  17. Model for tritiated water transport in soil

    International Nuclear Information System (INIS)

    Chemical forms of tritium released from nuclear facilities are mostly water (HTO) and hydrogen (HT, TT). Elemental tritium is inert in vegetation and superior animals, but the microorganisms from soil oxidize HT to HTO. After an atmospheric HT emission, in short time an equivalent quantity of HTO is re-emitted from soil. In the vicinity of a tritium source the spatial and temporary distribution of HTO is dependent on the chemical form of tritium releases. During routine tritium releases (continuously and constant releases), the local distribution of tritium reaches equilibrium, and specific activities of tritium in environmental compartments are almost equal. The situation is very different after an accidental emission. Having in view, harmful effects of tritium when it is incorporated into the body several models were developed for environmental tritium transport and dose assessment. The tritium transport into the soil is an important part of the environmental tritium behavior, but, unfortunately, in spite of the importance of this problem the corresponding modeling is unsatisfactory. The aim of this paper was the improvement of the TRICAIAP model, and the application of the model to BIOMOVS scenario. The BIOMOVS scenario predicts HTO concentrations in soil during 30 days, after one hour atmospheric HTO emission. The most important conclusions of the paper are: the principal carrier of tritium into the soil is water; the transfer processes are the reactions of water in soil and the diffusion due to concentration gradient; atmosphere-soil transport is dependent of surface characteristics (granulation, humidity, roughness, etc.); the conversion rate of HT to HTO is not well known and is dependent on active microorganism concentration in soil and on soil humidity. More experimental data are needed to decrease the uncertainty of transfer parameter, for the definition of the influence of vegetation, etc. (authors)

  18. Transport impacts on atmosphere and climate: Aviation

    Science.gov (United States)

    Lee, D. S.; Pitari, G.; Grewe, V.; Gierens, K.; Penner, J. E.; Petzold, A.; Prather, M. J.; Schumann, U.; Bais, A.; Berntsen, T.; Iachetti, D.; Lim, L. L.; Sausen, R.

    2010-12-01

    Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion. The last major international assessment of these impacts was made by the Intergovernmental Panel on Climate Change (IPCC) in 1999. Here, a comprehensive updated assessment of aviation is provided. Scientific advances since the 1999 assessment have reduced key uncertainties, sharpening the quantitative evaluation, yet the basic conclusions remain the same. The climate impact of aviation is driven by long-term impacts from CO 2 emissions and shorter-term impacts from non-CO 2 emissions and effects, which include the emissions of water vapour, particles and nitrogen oxides (NO x). The present-day radiative forcing from aviation (2005) is estimated to be 55 mW m -2 (excluding cirrus cloud enhancement), which represents some 3.5% (range 1.3-10%, 90% likelihood range) of current anthropogenic forcing, or 78 mW m -2 including cirrus cloud enhancement, representing 4.9% of current forcing (range 2-14%, 90% likelihood range). According to two SRES-compatible scenarios, future forcings may increase by factors of 3-4 over 2000 levels, in 2050. The effects of aviation emissions of CO 2 on global mean surface temperature last for many hundreds of years (in common with other sources), whilst its non-CO 2 effects on temperature last for decades. Much progress has been made in the last ten years on characterizing emissions, although major uncertainties remain over the nature of particles. Emissions of NO x result in production of ozone, a climate warming gas, and the reduction of ambient methane (a cooling effect) although the overall balance is warming, based upon current understanding. These NO x emissions from current subsonic aviation do not appear to deplete stratospheric ozone. Despite the progress made on modelling aviation's impacts on tropospheric chemistry, there remains a significant spread in model results. The knowledge of aviation's impacts on cloudiness

  19. Weakened atmospheric energy transport feedback in cold glacial climates

    Directory of Open Access Journals (Sweden)

    I. Cvijanovic

    2011-04-01

    Full Text Available The response of atmospheric energy transport during Northern Hemisphere cooling and warming from present day (PD and Last Glacial Maximum (LGM conditions is investigated using sea surface temperature anomalies derived from a freshwater hosing experiment. The present day climate shows enhanced sensitivity of the atmospheric energy transport compared to that of the LGM suggesting an ability of the PD atmosphere to reorganize more easily and thereby dampen temperature anomalies that may arise from changes in the oceanic transport. The increased PD sensitivity relative to that of the LGM is due mainly to a stronger dry static energy transport response which, in turn, is driven chiefly by larger changes in the transient eddy heat flux. In comparison, changes in latent heat transport play a minor role in the overall transport sensitivity.

  20. Atmospheric transport and deposition of Indonesian volcanic emissions

    Directory of Open Access Journals (Sweden)

    M. A. Pfeffer

    2005-11-01

    Full Text Available A regional climate model study has been performed to investigate the transport and atmospheric loss rates of emissions from Indonesian volcanoes and the sensitivity of these emissions to meteorological conditions and the solubility of the released emissions. Two experiments were conducted: 1 volcanic sulfur released as primarily SO2 and oxidation to SO42− determined by considering the major tropospheric chemical reactions; and 2 PbCl2 released as an infinitely soluble passive tracer. The first experiment was used to calculate SO2 loss rates from each active volcano resulting in an annual mean loss rate for all volcanoes of 1.1×10−5 s−1, or an e-folding rate of approximately 1 day. SO2 loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO2 loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a ''typical'' SO2 loss rate for volcanoes that are exposed to inconsistent winds. Within an average distance of 69 km away from the active Indonesian volcanoes, 53% of SO2 is lost due to conversion to SO42−, 42% due to dry deposition, and 5% is lost due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to have a major influence on their atmospheric transport and deposition. High concentrations of PbCl2 are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H2SO4. The ratio of the concentration of PbCl2 to SO2 is found to exponentially decay at increasing distance from the volcanoes

  1. Effect of Atmospheric Ions on Interfacial Water

    Directory of Open Access Journals (Sweden)

    Chien-Chang Kurt Kung

    2014-11-01

    Full Text Available The effect of atmospheric positivity on the electrical properties of interfacial water was explored. Interfacial, or exclusion zone (EZ water was created in the standard way, next to a sheet of Nafion placed horizontally at the bottom of a water-filled chamber. Positive atmospheric ions were created from a high voltage source placed above the chamber. Electrical potential distribution in the interfacial water was measured using microelectrodes. We found that beyond a threshold, the positive ions diminished the magnitude of the negative electrical potential in the interfacial water, sometimes even turning it to positive. Additionally, positive ions produced by an air conditioner were observed to generate similar effects; i.e., the electrical potential shifted in the positive direction but returned to negative when the air conditioner stopped blowing. Sometimes, the effect of the positive ions from the air conditioner was strong enough to destroy the structure of interfacial water by turning the potential decidedly positive. Thus, positive air ions can compromise interfacial water negativity and may explain the known negative impact of positive ions on health.

  2. Meridional Transport in the Atmospheres of Earth and Mars

    OpenAIRE

    Soto, Alejandro

    2015-01-01

    As we continue to discover terrestrial exoplanets, many with orbital and planetary characteristics drastically different from anything encountered in our solar system, we are likely to encounter 'exotic' atmospheric transport processes. As an example, we show an analysis of meridional transport from simulations Mars. These simulations provide insight into the differences in meridional transport between Earth and Mars, particularly through the role of a condensation flow. The differences betwe...

  3. Transport impacts on atmosphere and climate: Aviation

    OpenAIRE

    Lee, D. S.; G. Pitari; V. Grewe; Gierens, K.; Penner, J. E.; A. Petzold; Prather, M. J.; Schumann, U.; Bais, A.; T. Berntsen; Iachetti, D; Lim, L. L.; Sausen, R.

    2010-01-01

    Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion. The last major international assessment of these impacts was made by the Intergovernmental Panel on Climate Change (IPCC) in 1999. Here, a comprehensive updated assessment of aviation is provided. Scientific advances since the 1999 assessment have reduced key uncertainties, sharpening the quantitative evaluation, yet the basic conclusions remain the same. The climate impact of avi...

  4. Atmospheric transport, diffusion, and deposition of radioactivity

    International Nuclear Information System (INIS)

    From a meteorological standpoint there are two types of initial sources for atmospheric diffusion from Plowshare applications. One is the continuous point-source plume - a slow, small leak from an underground engineering application. The other is the large cloud produced almost instantaneously from a cratering application. For the purposes of this paper the effluent from neither type has significant fall speed. Both are carried by the prevailing wind, but the statistics of diffusion for each type are different. The use of constant altitude, isobaric and isentropic techniques for predicting the mean path of the effluent is briefly discussed. Limited data are used to assess the accuracy of current trajectory forecast techniques. Diffusion of continuous point-source plumes has been widely studied; only a brief review is given of the technique used and the variability of their results with wind speed and atmospheric stability. A numerical model is presented for computing the diffusion of the 'instantaneously-produced' large clouds. This model accounts for vertical and diurnal changes in atmospheric turbulence, wet and dry deposition, and radioactivity decay. Airborne concentrations, cloud size, and deposition on the ground are calculated. Pre- and post-shot calculations of cloud center, ground level concentration of gross radioactivity, and dry and wet deposition of iodine-131 are compared with measurements on Cabriolet and Buggy. (author)

  5. Transport impacts on atmosphere and climate: Metrics

    OpenAIRE

    J. S. Fuglestvedt; K. P. Shine; Berntsen, T.; Cook, J; Lee, D. S.; Stenke, A.; Skeie, R; Velders, G.J.M.; Waitz, I. A.

    2010-01-01

    The transport sector emits a wide variety of gases and aerosols, with distinctly different characteristics which influence climate directly and indirectly via chemical and physical processes. Tools that allow these emissions to be placed on some kind of common scale in terms of their impact on climate have a number of possible uses such as: in agreements and emission trading schemes; when considering potential trade-offs between changes in emissions resulting from technological or operational...

  6. Meridional Transport in the Atmospheres of Earth and Mars

    CERN Document Server

    Soto, Alejandro

    2015-01-01

    As we continue to discover terrestrial exoplanets, many with orbital and planetary characteristics drastically different from anything encountered in our solar system, we are likely to encounter 'exotic' atmospheric transport processes. As an example, we show an analysis of meridional transport from simulations Mars. These simulations provide insight into the differences in meridional transport between Earth and Mars, particularly through the role of a condensation flow. The differences between Earth and Mars are a reminder that there may be a wide variety of meridional transport processes at work across the range of observed terrestrial planets.

  7. Experimental and Numerical Studies of Atmosphere Water Interactions

    KAUST Repository

    Bou-Zeid, Elie

    2011-07-04

    Understanding and quantifying the interaction of the atmosphere with underlying water surfaces is of great importance for a wide range of scientific fields such as water resources management, climate studies of ocean-atmosphere exchange, and regional weat

  8. Passive water and ion transport by cotransporters

    DEFF Research Database (Denmark)

    Loo, D D; Hirayama, B A; Meinild, A K;

    1999-01-01

    1. The rabbit Na+-glucose (SGLT1) and the human Na+-Cl--GABA (GAT1) cotransporters were expressed in Xenopus laevis oocytes, and passive Na+ and water transport were studied using electrical and optical techniques. Passive water permeabilities (Lp) of the cotransporters were determined from...... the low Ea for water transport is similar to that of water channels (aquaporins). 4. GAT1 also behaved as an SKF89976A-sensitive water channel. We did not observe passive Na+ transport through GAT1. 5. We conclude that passive water and Na+ transport through cotransporters depend on different mechanisms...... the Lp of control oocytes. Passive Na+ transport (Na+ leak) was obtained from the blocker-sensitive Na+ currents in the absence of substrates (glucose and GABA). 2. Passive Na+ and water transport through SGLT1 were blocked by phlorizin with the same sensitivity (inhibitory constant (Ki), 3-5 micro...

  9. Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

    OpenAIRE

    H. Lei; X.-Z. Liang; D. J. Wuebbles; Tao, Z.

    2013-01-01

    Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), reactive mercury (Hg(II...

  10. Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

    OpenAIRE

    H. Lei; Liang, X.-Z.; D. J. Wuebbles; Tao, Z.

    2013-01-01

    Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), react...

  11. The Martian atmospheric water cycle as viewed from a terrestrial perspective

    Science.gov (United States)

    Zurek, Richard W.

    1988-01-01

    It is noted that the conditions of temperature and pressure that characterize the atmosphere of Mars are similar to those found in the Earth's stratosphere. Of particular significance is the fact that liquid water is unstable in both environments. Thus, it is expected that terrestrial studies of the dynamical behavior of stratospheric water should benefit the understanding of water transport on Mars as well.

  12. Burning water: the water footprint of biofuel-based transport

    OpenAIRE

    Gerbens-Leenes, P.W.; Hoekstra, A.Y.

    2010-01-01

    The trend towards substitution of conventional transport fuels by biofuels requires additional water. The EU aims to replace 10 percent of total transport fuels by biofuels by 2020. This study calculates the water footprint (WF) of different transport modes using bio-ethanol, biodiesel or bio-electricity and of European transport if 10 percent of transport fuels is replaced by bio-ethanol. We compare results for Europe with similar goals for other regions (Africa, Asia, Latin America, the for...

  13. Transport of solar protons through the atmosphere during GLE

    International Nuclear Information System (INIS)

    Using the PLANETOCOSMICS simulation framework we simulated solar proton transport through the Earth's atmosphere and estimated angular and energy distributions of secondaries (protons, electrons, positrons, muons, photons and neutrons) at various atmospheric levels. As the source spectrum of solar protons at the boundary of atmosphere the spectra obtained with the GLE modeling from the data of neutron monitor network in a number of events have been used. These Monte Carlo simulation results were compared with the available solar cosmic ray neutron monitor and balloon measurements. The calculated solar proton spectra are in good agreement with the balloon and neutron monitor observational data.

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

    CERN Document Server

    Knietzsch, Marc-Andre; Lunkeit, Frank

    2014-01-01

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

  15. Burning water: the water footprint of biofuel-based transport

    NARCIS (Netherlands)

    Gerbens-Leenes, P.W.; Hoekstra, A.Y.

    2010-01-01

    The trend towards substitution of conventional transport fuels by biofuels requires additional water. The EU aims to replace 10 percent of total transport fuels by biofuels by 2020. This study calculates the water footprint (WF) of different transport modes using bio-ethanol, biodiesel or bio-electr

  16. Field-scale water flow and solute transport : Swap model concepts, parameter estimation and case studies

    NARCIS (Netherlands)

    Dam, van J.C.

    2000-01-01

    Water flow and solute transport in top soils are important elements in many environmental studies. The agro- and ecohydrological model SWAP (Soil-Water-Plant-Atmosphere) has been developed to simulate simultaneously water flow, solute transport, heat flow and crop growth at field scale level. The ma

  17. Global Atmospheric Transport and Source-Receptor Relationships for Arsenic.

    Science.gov (United States)

    Wai, Ka-Ming; Wu, Shiliang; Li, Xueling; Jaffe, Daniel A; Perry, Kevin D

    2016-04-01

    Arsenic and many of its compounds are toxic pollutants in the global environment. They can be transported long distances in the atmosphere before depositing to the surface, but the global source-receptor relationships between various regions have not yet been assessed. We develop the first global model for atmospheric arsenic to better understand and quantify its intercontinental transport. Our model reproduces the observed arsenic concentrations in surface air over various sites around the world. Arsenic emissions from Asia and South America are found to be the dominant sources for atmospheric arsenic in the Northern and Southern Hemispheres, respectively. Asian emissions are found to contribute 39% and 38% of the total arsenic deposition over the Arctic and Northern America, respectively. Another 14% of the arsenic deposition to the Arctic region is attributed to European emissions. Our results indicate that the reduction of anthropogenic arsenic emissions in Asia and South America can significantly reduce arsenic pollution not only locally but also globally. PMID:26906891

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

    Directory of Open Access Journals (Sweden)

    M.-A. Knietzsch

    2014-11-01

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

  19. Atmospheric nitrogen compounds II: emissions, transport, transformation, deposition and assessment

    Science.gov (United States)

    Aneja, Viney P.; Roelle, Paul A.; Murray, George C.; Southerland, James; Erisman, Jan Willem; Fowler, David; Asman, Willem A. H.; Patni, Naveen

    The Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment workshop was held in Chapel Hill, NC from 7 to 9 June 1999. This international conference, which served as a follow-up to the workshop held in March 1997, was sponsored by: North Carolina Department of Environment and Natural Resources; North Carolina Department of Health and Human Services, North Carolina Office of the State Health Director; Mid-Atlantic Regional Air Management Association; North Carolina Water Resources Research Institute; Air and Waste Management Association, RTP Chapter; the US Environmental Protection Agency and the North Carolina State University (College of Physical and Mathematical Sciences, and North Carolina Agricultural Research Service). The workshop was structured as an open forum at which scientists, policy makers, industry representatives and others could freely share current knowledge and ideas, and included international perspectives. The workshop commenced with international perspectives from the United States, Canada, United Kingdom, the Netherlands, and Denmark. This article summarizes the findings of the workshop and articulates future research needs and ways to address nitrogen/ammonia from intensively managed animal agriculture. The need for developing sustainable solutions for managing the animal waste problem is vital for shaping the future of North Carolina. As part of that process, all aspects of environmental issues (air, water, soil) must be addressed as part of a comprehensive and long-term strategy. There is an urgent need for North Carolina policy makers to create a new, independent organization that will build consensus and mobilize resources to find technologically and economically feasible solutions to this aspect of the animal waste problem.

  20. Impact of carbonation on water transport properties of cementitious materials

    International Nuclear Information System (INIS)

    Carbonation is a very well-known cementitious materials pathology. It is the major cause of reinforced concrete structures degradation. It leads to rebar corrosion and consequent concrete cover cracking. In the framework of radioactive waste management, cement-based materials used as building materials for structures or containers would be simultaneously submitted to drying and atmospheric carbonation. Although scientific literature regarding carbonating is vast, it is clearly lacking information about the influence of carbonation on water transport properties. This work then aimed at studying and understanding the change in water transport properties induced by carbonation. Simultaneously, the representativeness of accelerated carbonation (in the laboratory) was also studied. (author)

  1. Water transport; 1 : 4 000 000

    International Nuclear Information System (INIS)

    On this map the water transport on the territory of the Slovak Republic and Central Europe is shown. Structure of goods transported in 2000, direction and amount of goods transported in 2000 as well as loading and unloading of goods in 2000 are analysed

  2. Future impact of transport emissions on the global atmospheric chemistry

    Science.gov (United States)

    Koffi, B.; Szopa, S.; Cozic, A.

    2009-04-01

    Emissions of air pollutants by road, air traffic and international shipping affect air quality and climate. Besides their effect on the ozone concentration and its related radiative forcing, they also affect the OH-concentration, i.e. the oxidizing capacity of the atmosphere. The pollutants are emitted by the three transport sectors into highly different environments. The O3 and OH potential productions induced by each of these sectors thus differ strongly. These transport emissions are expected to show drastic quantitative and geographic changes in the next decades, because of new emission regulations, increasing mobility, as well as demographic and economic growths. In addition to changes in emissions, significant changes in climate parameters such as H2O, temperature, and dynamics are expected to occur in the future global atmosphere. They will affect the oxidation processes and thereby the changes in the atmospheric concentrations induced by transport emissions. Within the EU-project QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) the LMDz-INCA climate-chemistry model was used to estimate the effect of transport emissions on the global atmospheric chemical composition. In a first step, up-to-date emission datasets were used for the transport and non-transport anthropogenic emissions for present (2000) and future (2050, SRES A1b and B1 scenarios) using 2003 nudged meteorology. A strong reduction of the road emissions and a moderate (B1) to high (A1b) increase of the ship and aircraft emissions are expected by the year 2050. As a consequence, the impact of road emissions on ozone is shown to decrease drastically, whereas aviation would become the major transport sources of tropospheric ozone perturbation at global scale. According to the most likely scenario (A1b), the contribution of all transport modes to the ozone column would increase everywhere, reaching up to 13% in some areas such as Asia. In a second step of the study

  3. Predicting water transport in multilayer coatings

    NARCIS (Netherlands)

    Baukh, V.; Huinink, H.P.; Adan, O.C.G.; Erich, S.J.F.; Ven, L.G.J. van der

    2012-01-01

    Water transport in polymer coatings is a key process in their failure. Mostly, such systems are composed of multiple layers to meet the required specifications. Understanding water transport requires a model that relates the kinetics with the properties of the layers. In this article a theoretical m

  4. ATTILA - Atmospheric Tracer Transport In a Langrangian Model

    Energy Technology Data Exchange (ETDEWEB)

    Reithmeier, C.; Sausen, R.

    2000-07-01

    The Lagrangian model ATTILA (atmospheric tracer transport in a Lagrangian model) has been developed to treat the global-scale transport of passive trace species in the atmosphere within the framework of a general circulation model (GCM). ATTILA runs online within the GCM ECHAM4 and uses the GCM produced wind field to advect the centrois of 80.000 to 180.000 constant mass air parcels into which the model atmosphere is divided. Each trace constituent is thereby represented by a mass mixing ratio in each parcel. ATTILA contains state-of-the-art parameterizations of convection, turbulent boundary layer mixing, and interparcel transport and provides an algorithm to map the tracer concentrations from the trajectories to the ECHAM model grid. We use two experiments to evaluate the transport characteristics of ATTILA against observations and the standard semiLagrangian transport scheme of ECHAM. In the first experiment we simulate the distribution of the short-lived tracer Radon ({sup 222}Rn) in order to examine fast vertical transport over continents, and long-range transport from the continents to remote areas. In the second experiment, we simulate the distribution of radiocarbon ({sup 14}C) that was injected into the northern stratosphere during the nuclear weapon tests in the early 60ties, in order to examine upper tropospheric and stratospheric transport characteristics. ATTILA compares well to the observations and in many respects to the semiLagrangian scheme. However, contrary to the semiLagrangian scheme, ATTILA shows a greatly reduced meridional transport in the upper troposphere and lower stratosphere, and a reduced downward flux from the stratosphere to the troposphere, especially in midlatitudes. Since both transport schemes use the same model meteorology, we conclude that the often cited enhanced meridional transport and overestimated downward flux in ECHAM as described above is rather due to the numerical properties of the semiLagrangian scheme than due to an

  5. Isotopes in the Arctic atmospheric water cycle

    Science.gov (United States)

    Bonne, Jean-Louis; Werner, Martin; Meyer, Hanno; Kipfstuhl, Sepp; Rabe, Benjamin; Behrens, Melanie; Schönicke, Lutz; Steen Larsen, Hans Christian; Masson-Delmotte, Valérie

    2016-04-01

    The ISO-ARC project aims at documenting the Arctic atmospheric hydrological cycle, by assessing the imprint of the marine boundary conditions (e.g. temperature variations, circulation changes, or meltwater input) to the isotopic composition of the atmospheric water cycle (H218O and HDO) with a focus on North Atlantic and Arctic oceans. For this purpose, two continuous monitoring water vapour stable isotopes cavity ring-down spectrometers have been installed in July 2015: on-board the Polarstern research vessel and in the Siberian Lena delta Samoylov research station (N 72° 22', E 126° 29'). The Polarstern measurements cover the summer 2015 Arctic campaign from July to mid-October, including six weeks in the Fram Strait region in July- August, followed by a campaign reaching the North Pole and a transect from the Norwegian Sea to the North Sea. These vapour observations are completed by water isotopic measurements in samples from the surface ocean water for Polarstern and from precipitation in Samoylov and Tiksi (120 km south-east of the station). A custom-made designed automatic calibration system has been implemented in a comparable manner for both vapour instruments, based on the injection of different liquid water standards, which are completely vaporised in dry air at high temperature. Subsequent humidity level can be adjusted from 2000 to at least 30000 ppm. For a better resilience, an independent calibration system has been added on the Samoylov instrument, allowing measurements of one standard at humidity levels ranging from 2000 to 15000 ppm: dry air is introduced in a tank containing a large amount of liquid water standard, undergoing evaporation under a controlled environment. The measurement protocol includes an automatic calibration every 25 hours. First instrument characterisation experiments depict a significant isotope-humidity effect at low humidity, dependant on the isotopic composition of the standard. For ambient air, our first isotope

  6. A model for radionuclide transport in the Cooling Water System

    International Nuclear Information System (INIS)

    A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA

  7. Development of atmosphere-soil-vegetation model for investigation of radioactive materials transport in terrestrial biosphere

    International Nuclear Information System (INIS)

    In order to investigate the transport of radionuclides in the terrestrial biosphere we have developed a one-dimensional numerical model named SOLVEG that predicts the transfer of water, heat, and gaseous and particulate matters in atmosphere-soil-vegetation system. The SOLVEG represents atmosphere, soil, and vegetation as an aggregation of several layers. Basic equations used in the model are solved using the finite difference method. Most of predicted variables are interrelated with the source/sink terms of momentum, water, heat, gases, and particles based on mathematically described biophysical processes in atmosphere, soil and vegetation. The SOLVEG can estimate dry, wet and fog deposition of gaseous and particulate matters at each canopy layer. Performance tests of the SOLVEG with several observational sites were carried out. The SOLVEG predicted the observed temporal changes in water vapor, CO2, and ozone fluxes over vegetated surfaces. The SOLVEG also reproduced measured fluxes of fog droplets and of fine aerosols over the forest. (author)

  8. PCBs in the Arctic atmosphere: determining important driving forces using a global atmospheric transport model

    Science.gov (United States)

    Friedman, Carey L.; Selin, Noelle E.

    2016-03-01

    We present a spatially and temporally resolved global atmospheric polychlorinated biphenyl (PCB) model, driven by meteorological data, that is skilled at simulating mean atmospheric PCB concentrations and seasonal cycles in the Northern Hemisphere midlatitudes and mean Arctic concentrations. However, the model does not capture the observed Arctic summer maximum in atmospheric PCBs. We use the model to estimate global budgets for seven PCB congeners, and we demonstrate that congeners that deposit more readily show lower potential for long-range transport, consistent with a recently described "differential removal hypothesis" regarding the hemispheric transport of PCBs. Using sensitivity simulations to assess processes within, outside, or transport to the Arctic, we examine the influence of climate- and emissions-driven processes on Arctic concentrations and their effect on improving the simulated Arctic seasonal cycle. We find evidence that processes occurring outside the Arctic have a greater influence on Arctic atmospheric PCB levels than processes that occur within the Arctic. Our simulations suggest that re-emissions from sea ice melting or from the Arctic Ocean during summer would have to be unrealistically high in order to capture observed temporal trends of PCBs in the Arctic atmosphere. We conclude that midlatitude processes are likely to have a greater effect on the Arctic under global change scenarios than re-emissions within the Arctic.

  9. PCBs in the Arctic atmosphere: determining important driving forces using a global atmospheric transport model

    Directory of Open Access Journals (Sweden)

    C. L. Friedman

    2015-11-01

    Full Text Available We present a spatially and temporally resolved global atmospheric PCB model, driven by meteorological data, that is skilled at simulating mean atmospheric PCB concentrations and seasonal cycles in the Northern Hemisphere mid-latitudes, and mean Arctic concentrations. However, the model does not capture the observed Arctic summer maximum in atmospheric PCBs. We use the model to estimate global budgets for the International Council for the Exploration of the Sea 7 PCBs, and demonstrate that congeners that deposit more readily show lower potential for long-range transport, consistent with a recently-described "differential removal hypothesis" regarding the hemispheric transport of PCBs. Using sensitivity simulations to assess processes within, outside, or transport to the Arctic, we examine the influence of climate- and emissions-driven processes on Arctic concentrations and their effect on improving the simulated Arctic seasonal cycle. We find evidence that processes occurring outside the Arctic have a greater influence on Arctic atmospheric PCB levels than processes that occur within the Arctic. Our simulations suggest that re-emissions from sea ice melting or from the Arctic Ocean during summer would have to be unrealistically high in order to capture observed temporal trends of PCBs in the Arctic atmosphere. We conclude that mid-latitude processes are likely to have a greater effect on the Arctic under global change scenarios than re-emissions within the Arctic.

  10. Comparison of curved trajectory atmospheric transport vs. assumed straight-line transport

    International Nuclear Information System (INIS)

    The Dose-To-Man program as currently being implemented at the Savannah River Laboratory provides estimates of the environmental effects of Savannah River Plant operations. These estimates utilize a polar grid structure and assume straight-line transport of materials released to the atmosphere to distances beyond grid boundaries. The assumption of straight-line transport is standard for such estimates and greatly simplifies the computations involved in providing estimates of effects. Generally, the atmospheric transport trajectory will be curved; and, for distances out to 100 km or so, the assumption may lead to significant error. Therefore, a computer code was constructed to provide an estimate of the curved trajectory transport relative to straight-line transport over an extended time period

  11. Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET)

    International Nuclear Information System (INIS)

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses that individuals may have received from operations at the Hanford Site since 1944. This report deals specifically with the atmospheric transport model, Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). RATCHET is a major rework of the MESOILT2 model used in the first phase of the HEDR Project; only the bookkeeping framework escaped major changes. Changes to the code include (1) significant changes in the representation of atmospheric processes and (2) incorporation of Monte Carlo methods for representing uncertainty in input data, model parameters, and coefficients. To a large extent, the revisions to the model are based on recommendations of a peer working group that met in March 1991. Technical bases for other portions of the atmospheric transport model are addressed in two other documents. This report has three major sections: a description of the model, a user's guide, and a programmer's guide. These sections discuss RATCHET from three different perspectives. The first provides a technical description of the code with emphasis on details such as the representation of the model domain, the data required by the model, and the equations used to make the model calculations. The technical description is followed by a user's guide to the model with emphasis on running the code. The user's guide contains information about the model input and output. The third section is a programmer's guide to the code. It discusses the hardware and software required to run the code. The programmer's guide also discusses program structure and each of the program elements

  12. Atmospheric pollution in the mediterranean area: geochemical studies of aerosols and rain waters

    International Nuclear Information System (INIS)

    It is now recognised that the atmosphere is a major pathway for the transport of material to the oceans. The material in the atmosphere is present as gaseous and particulate (aerosol) phases. Aerosols may be removed from the atmosphere by a combination of 'dry' (i.e. not involving an atmospheric aqueous phase) and 'wet' (precipitation scavenging) processes. Thus, aerosols are intimately related to rain waters, and interactions between the two are discusses below in relation to the input of material to the Mediterranean Sea

  13. INTRODUCTION: Anticipated changes in the global atmospheric water cycle

    Science.gov (United States)

    Allan, Richard P.; Liepert, Beate G.

    2010-06-01

    The atmospheric branch of the water cycle, although containing just a tiny fraction of the Earth's total water reserves, presents a crucial interface between the physical climate (such as large-scale rainfall patterns) and the ecosystems upon which human societies ultimately depend. Because of the central importance of water in the Earth system, the question of how the water cycle is changing, and how it may alter in future as a result of anthropogenic changes, present one of the greatest challenges of this century. The recent Intergovernmental Panel on Climate Change report on Climate Change and Water (Bates et al 2008) highlighted the increasingly strong evidence of change in the global water cycle and associated environmental consequences. It is of critical importance to climate prediction and adaptation strategies that key processes in the atmospheric water cycle are precisely understood and determined, from evaporation at the surface of the ocean, transport by the atmosphere, condensation as cloud and eventual precipitation, and run-off through rivers following interaction with the land surface, sub-surface, ice, snow and vegetation. The purpose of this special focus issue of Environmental Research Letters on anticipated changes in the global atmospheric water cycle is to consolidate the recent substantial advances in understanding past, present and future changes in the global water cycle through evidence built upon theoretical understanding, backed up by observations and borne out by climate model simulations. Thermodynamic rises in water vapour provide a central constraint, as discussed in a guest editorial by Bengtsson (2010). Theoretical implications of the Clausius-Clapeyron equation are presented by O'Gorman and Muller (2010) and with reference to a simple model (Sherwood 2010) while observed humidity changes confirm these anticipated responses at the land and ocean surface (Willett et al 2008). Rises in low-level moisture are thought to fuel an

  14. Quantifying atmospheric transport, chemistry, and mixing using a new trajectory-box model and a global atmospheric-chemistry GCM

    OpenAIRE

    H. Riede; Jöckel, P.; Sander, R.

    2009-01-01

    We present a novel method for the quantification of transport, chemistry, and mixing along atmospheric trajectories based on a consistent model hierarchy. The hierarchy consists of the new atmospheric-chemistry trajectory-box model CAABA/MJT and the three-dimensional (3-D) global ECHAM/MESSy atmospheric-chemistry (EMAC) general circulation model. CAABA/MJT employs the atmospheric box model CAABA in a configuration using the atmospheric-chemistry submodel MECCA (M), the photochemistry submodel...

  15. Osmotic water transport through carbon nanotube membranes

    OpenAIRE

    Kalra, Amrit; Garde, Shekhar; Hummer, Gerhard

    2003-01-01

    We use molecular dynamics simulations to study osmotically driven transport of water molecules through hexagonally packed carbon nanotube membranes. Our simulation setup comprises two such semipermeable membranes separating compartments of pure water and salt solution. The osmotic force drives water flow from the pure-water to the salt-solution compartment. Monitoring the flow at molecular resolution reveals several distinct features of nanoscale flows. In particular, thermal fluctuatio...

  16. Operational simulation of continental water masses consistent with atmospheric and oceanic data.

    OpenAIRE

    Robert Dill; Walter, C.;  

    2008-01-01

    Operational global mass transport data of the atmosphere and the oceans are widely used for studies of earth rotation excitation and gravity field simulations and are essential for GRACE dealising purposes, too. Seasonal and short periodic variations are also caused by continental water mass redistributions. In order to account for the continental hydrology processes as well and to close the global water cycle, continental water mass storage fields and fluxes are needed in the same operationa...

  17. Atmospheric nitrogen in the Mississippi River Basin - Amissions, deposition and transport

    Science.gov (United States)

    Lawrence, G.B.; Goolsby, D.A.; Battaglin, W.A.; Stensland, G.J.

    2000-01-01

    Atmospheric deposition of nitrogen has been cited as a major factor in the nitrogen saturation of forests in the north-eastern United States and as a contributor to the eutrophication of coastal waters, including the Gulf of Mexico near the mouth of the Mississippi River. Sources of nitrogen emissions and the resulting spatial patterns of nitrogen deposition within the Mississippi River Basin, however, have not been fully documented. An assessment of atmospheric nitrogen in the Mississippi River Basin was therefore conducted in 1998-1999 to: (1) evaluate the forms in which nitrogen is deposited from the atmosphere; (2) quantify the spatial distribution of atmospheric nitrogen deposition throughout the basin; and (3) relate locations of emission sources to spatial deposition patterns to evaluate atmospheric transport. Deposition data collected through the NADP/NTN (National Atmospheric Deposition Program/National Trends Network) and CASTNet (Clean Air Status and Trends Network) were used for this analysis. NO(x) Tier 1 emission data by county was obtained for 1992 from the US Environmental Protection Agency (Emissions Trends Viewer CD, 1985-1995, version 1.0, September 1996) and NH3 emissions data was derived from the 1992 Census of Agriculture (US Department of Commerce. Census of Agriculture, US Summary and County Level Data, US Department of Commerce, Bureau of the Census. Geographic Area series, 1995:1b) or the National Agricultural Statistics Service (US Department of Agriculture. National Agricultural Statistics Service Historical Data. Accessed 7/98 at URL, 1998. http://www.usda.gov/nass/pubs/hisdata.htm). The highest rates of wet deposition of NO3- were in the north-eastern part of the basin, downwind of electric utility plants and urban areas, whereas the highest rates of wet deposition of NH4+ were in Iowa, near the center of intensive agricultural activities in the Midwest. The lowest rates of atmospheric nitrogen deposition were on the western (windward

  18. Atmospheric nitrogen in the Mississippi River Basin. Emissions, deposition and transport

    International Nuclear Information System (INIS)

    Atmospheric deposition of nitrogen has been cited as a major factor in the nitrogen saturation of forests in the north-eastern United States and as a contributor to the eutrophication of coastal waters, including the Gulf of Mexico near the mouth of the Mississippi River. Sources of nitrogen emissions and the resulting spatial patterns of nitrogen deposition within the Mississippi River Basin, however, have not been fully documented. An assessment of atmospheric nitrogen in the Mississippi River Basin was therefore conducted in 1998-1999 to: (1) evaluate the forms in which nitrogen is deposited from the atmosphere; (2) quantify the spatial distribution of atmospheric nitrogen deposition throughout the basin; and (3) relate locations of emission sources to spatial deposition patterns to evaluate atmospheric transport. Deposition data collected through the NADP/NTN (National Atmospheric Deposition Program/National Trends Network) and CASTNet (Clean Air Status and Trends Network) were used for this analysis. NOx Tier 1 emission data by county was obtained for 1992 from the US Environmental Protection Agency (Emissions Trends Viewer CD, 1985-1995, version 1.0, September 1996) and NH3 emissions data was derived from the 1992 Census of Agriculture (US Department of Commerce. Census of Agriculture, US Summary and County Level Data, US Department of Commerce, Bureau of the Census. Geographic Area series, 1995:1b) or the National Agricultural Statistics Service (US Department of Agriculture. National Agricultural Statistics Service Historical Data. Accessed 7/98 at URL, 1998. http://www.usda.gov/nass/pubs/hisdata.htm). The highest rates of wet deposition of NO3- were in the north-eastern part of the basin, downwind of electric utility plants and urban areas, whereas the highest rates of wet deposition of NH4+ were in Iowa, near the center of intensive agricultural activities in the Midwest. The lowest rates of atmospheric nitrogen deposition were on the western (windward

  19. Lagrangian coherent structures as mesoscale transport barriers in atmospheric flows

    Science.gov (United States)

    Naik, Shibabrat; Ross, Shane

    2015-11-01

    Coherent structures in two-dimensional flows have long been studied in the context of transport in fluid dynamics. However, for geophysical systems a small vertical velocity can lead to nontrivial three-dimensional motion of airborne biological populations affecting agriculture or hazardous outputs from natural disasters. The pathways and barriers in the lower atmosphere, from ground level to a kilometer altitude and over a horizontal scale of several kilometers-which bridge the scale of, for example, local farmlands to the larger regional scale-are still unclear. This requires exploring relevant spatiotemporal scales related to advection in the space of 3D + time. In this talk, we will present the application of finite-time Lyapunov exponent based three-dimensional Lagrangian coherent structures (LCS) to address questions of transport using historical data sets from satellite observations, field measurements and the Weather Research and Forecasting (WRF) model.

  20. Atmospheric transport and deposition of pesticides: An assessment of current knowledge

    DEFF Research Database (Denmark)

    Pul, W.A.J. van; Bidleman, T.F.; Brorström-Lunden, E.; Builtjes, P.J.H.; Dutchak, S.; Duyzer, J.H.; Gryning, Sven-Erik; Jones, K.C.; Dijk, H.F.G. van; Jaarsveld, J.A. van

    are present in the exchange processes at the interface between air and soil/water/vegetation. In all process descriptions the uncertainty in the physicochemical properties play an important role. Particularly those in the vapour pressure, Henry's law constant and its temperature dependency. More......The current knowledge on atmospheric transport and deposition of pesticides is reviewed and discussed by a working group of experts during the Workshop on Fate of pesticides in the atmosphere; implications for risk assessment, held in Driebergen, the Netherlands, 22-24 April, 1998. In general there...... is a shortage of measurement data to evaluate the deposition and reemission processes. It was concluded that the mechanisms of transport and dispersion of pesticides can be described similarly to those for other air pollution components and these mechanisms are rather well-known. Large uncertainties...

  1. Water loss from terrestrial planets with CO2-rich atmospheres

    OpenAIRE

    Wordsworth, Robin; Pierrehumbert, Raymond

    2013-01-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the mi...

  2. Towards robust regional estimates of CO_2 sources and sinks using atmospheric transport models

    OpenAIRE

    Gurney, Kevin Robert; Randerson, James

    2002-01-01

    Information about regional carbon sources and sinks can be derived from variations in observed atmospheric CO_2 concentrations via inverse modelling with atmospheric tracer transport models. A consensus has not yet been reached regarding the size and distribution of regional carbon fluxes obtained using this approach, partly owing to the use of several different atmospheric transport models. Here we report estimates of surface–atmosphere CO_2 fluxes from an intercomparison of atmospheric CO_2...

  3. Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models

    OpenAIRE

    Randerson, JT; Gurney, KR; Law, RM; Denning, AS; Rayner, PJ; Baker, D.; Bousquet, P.; Bruhwiler, L.; Chen, YH; Ciais, P.; Fan, S.; Fung, IY; Gloor, M.; Heimann, M.; Higuchi, K

    2002-01-01

    Information about regional carbon sources and sinks can be derived from variations in observed atmospheric CO2 concentrations via inverse modelling with atmospheric tracer transport models. A consensus has not yet been reached regarding the size and distribution of regional carbon fluxes obtained using this approach, partly owing to the use of several different atmospheric transport models(1-9). Here we report estimates of surface- atmosphere CO2 fluxes from an intercomparison of atmospheric ...

  4. Chemical transport modeling of potential atmospheric CO2 sinks

    International Nuclear Information System (INIS)

    The potential for carbon dioxide (CO2) sequestration via engineered chemical sinks is investigated using a three dimensional chemical transport model (CTM). Meteorological and chemical constraints for flat or vertical systems that would absorb CO2 from the atmosphere, as well as an example chemical system of calcium hydroxide (Ca(OH)2) proposed by Elliott et al. [Compensation of atmospheric CO2 buildup through engineered chemical sinkage, Geophys. Res. Lett. 28 (2001) 1235] are reviewed. The CTM examines land based deposition sinks, with 4ox5o latitude/longitude resolution at various locations, and deposition velocities (v). A maximum uptake of ∼20 Gton (1015 g) C yr-1 is attainable with v>5 cm s -1 at a mid-latitude site. The atmospheric increase of CO2 (3 Gton yr-1) can be balanced by an engineered sink with an area of no more than 75,000 km2 at v of 1 cm s-1. By building the sink upwards or splitting this area into narrow elements can reduce the active area by more than an order of magnitude as discussed in Dubey at el. [31]. (author)

  5. Atmospheric occurrence, transport and deposition of polychlorinated biphenyls and hexachlorobenzene in the Mediterranean and Black Seas

    Directory of Open Access Journals (Sweden)

    N. Berrojalbiz

    2014-04-01

    Full Text Available The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to direct and indirect loads of atmospheric inputs of organochlorine compounds (OCl from primary and secondary sources. Here we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where gas phase and aerosol samples were collected. Both matrices were analyzed for 41 polychlorinated biphenyls (PCBs, including dioxin-like congeners, and hexachlorobencene (HCB. The values reported in this study for gas phase HCB and ∑41PCB (LOD to 418.3 pg m−3 and from 81.99 to 931.6 pg m−3 respectively are in the same range of those reported in former studies, possibly suggesting a limited decline in their atmospheric concentrations during the last decade for the Mediterranean region due to land base OCl sources. There is a clear influence of the direction of the air-mass on the atmospheric concentrations of PCBs, with higher concentrations when the air mass was from southern Europe, and the lowest concentrations for air masses coming from the SW Mediterranean and Atlantic Ocean. PCBs and HCB are close to air–water equilibrium for most sampling periods, thus resulting in low atmospheric deposition fluxes at open sea. This is consistent with the oligotrophic character of the Mediterranean Sea with a small influence of the biological pump capturing atmospheric PCBs. Therefore, degradation of gas-phase PCBs by OH radicals is estimated to be the main loss process of atmospheric PCBs during their transport over the Mediterranean Sea. Conversely, atmospheric residence times of HCB are predicted to be very long due to a lack of atmospheric degradation and low depositional fluxes due to concentrations at air–water equilibrium.

  6. Coupled modeling system for prediction of radioactive material transport in the atmospheric, terrestrial, and oceanic environment

    International Nuclear Information System (INIS)

    A coupling numerical modeling system named SPEEDI-MP has been developed to simulate the complicated transfer process of radioactive materials in the environment. The coupled model for regional water and material cycles consists of the seven models: the non-hydrostatic atmospheric dynamic model (MM5), detailed multi-layer land surface model (SOLVEG) and three-dimensional hydrology model (RIVERS), the third-generation ocean wind-wave model (WW3), the Princeton Ocean Model (POM), and Lagrangian particle dispersion models for the atmosphere (GEARM) and ocean (SEA-GEARN). By using a general-purpose model coupling program, the above models were integrated to simulate regional water and material transports. Test calculations were carried out under a hypothetical release of the tritiated water vapor to the atmosphere in the river basin of Ibaraki in Japan to investigate the effects of rainfall, runoff, and re-emission processes on the deposition pattern. The SPEEDI-MP overall reproduced the rainfall and river flow which play an important role in the material cycle. The result showed that the deposited tritiated water vapor at the ground after the heavy rainfall event because the surface runoff increased in the river basin. Both processes of surface runoff and re-emission of the deposited tritiated water vapor in SPEEDI-MP significantly expanded the contaminated areas. (author)

  7. Field-scale water flow and solute transport : Swap model concepts, parameter estimation and case studies

    OpenAIRE

    Van Dam

    2000-01-01

    Water flow and solute transport in top soils are important elements in many environmental studies. The agro- and ecohydrological model SWAP (Soil-Water-Plant-Atmosphere) has been developed to simulate simultaneously water flow, solute transport, heat flow and crop growth at field scale level. The main features and theoretical concepts of SWAP are described.A serious limitation of many model applications is the availability of accurate input parameters. With the rapid increase of processor cal...

  8. Heat transport of nitrogen in helium atmospheric pressure microplasma

    CERN Document Server

    Xu, Shaofeng

    2013-01-01

    Stable DC atmospheric pressure normal glow discharges in ambient air were produced between the water surface and the metallic capillary coupled with influx of helium gas. Multiple independent repeated trials indicated that vibrational temperature of nitrogen rises from 3200 to 4622 K, and rotational temperature of nitrogen decreases from 1270 to 570 K as gas flux increasing from 20 to 80 sccm and discharge current decreasing from 11 to 3 mA. Furthermore, it was found that the vibrational degree of the nitrogen molecule has priority to gain energy than the rotational degree of nitrogen molecule in nonequilibrium helium microplasma.

  9. Atmospheric transport, clouds and the Arctic longwave radiation paradox

    Science.gov (United States)

    Sedlar, Joseph

    2016-04-01

    Clouds interact with radiation, causing variations in the amount of electromagnetic energy reaching the Earth's surface, or escaping the climate system to space. While globally clouds lead to an overall cooling radiative effect at the surface, over the Arctic, where annual cloud fractions are high, the surface cloud radiative effect generally results in a warming. The additional energy input from absorption and re-emission of longwave radiation by the clouds to the surface can have a profound effect on the sea ice state. Anomalous atmospheric transport of heat and moisture into the Arctic, promoting cloud formation and enhancing surface longwave radiation anomalies, has been identified as an important mechanism in preconditioning Arctic sea ice for melt. Longwave radiation is emitted equally in all directions, and changes in the atmospheric infrared emission temperature and emissivity associated with advection of heat and moisture over the Arctic should correspondingly lead to an anomalous signal in longwave radiation at the top of the atmosphere (TOA). To examine the role of atmospheric heat and moisture transport into the Arctic on TOA longwave radiation, infrared satellite sounder observations from AIRS during 2003-2014 are analyzed for summer (JJAS). Thermodynamic metrics are developed to identify months characterized by a high frequency of warm and moist advection into the Arctic, and segregate the 2003-14 time period into climatological and anomalously warm, moist summer months. We find that anomalously warm, moist months result in a significant TOA longwave radiative cooling, which is opposite the forcing signal that the surface experiences during these months. At the timescale of the advective events, 3-10 days, the TOA cooling can be as large as the net surface energy budget during summer. When averaged on the monthly time scale, and over the full Arctic basin (poleward of 75°N), summer months experiencing frequent warm, moist advection events are

  10. The role of moisture transport between ground and atmosphere in global change

    International Nuclear Information System (INIS)

    Projections of the effect of climate change on future water availability are examined by reviewing the formulations used to calculate moisture transport between the ground and the atmosphere. General circulation models and climate change impact models have substantially different formulations for evapotranspiration, so their projections of future water availability often disagree, even though they use the same temperature and precipitation forecasts. General circulation models forecast little change in tropical and subtropical water availability, while impact models show severe water and agricultural shortages. A comparison of observations and modeling techniques shows that the parameterizations in general circulation models likely lead to an underestimate of the impacts of global warming on soil moisture and vegetation. Such errors would crucially affect the temperature and precipitation forecasts used in impact models. Some impact model evaporation formulations are probably more appropriate than those in general circulation models, but important questions remain. More observations are needed, especially in the vicinity of forests, to determine appropriate parameterizations

  11. International agreements to control the transboundary atmospheric transport of toxic substances

    International Nuclear Information System (INIS)

    As late as 1972, air pollution was considered to be only a local concern. That perception began to change as the effects of long-range transport of acidifying substances on downwind receptors was demonstrated, leading to adoption of acid rain control programs in many countries. It also became evident that other harmful substances could be transported over long distances through the atmosphere. Organochlorine compounds and heavy metals were of particular concern. The international agreements that could be used to control the transboundary atmospheric transport of toxic substance are described along with current activities being undertaken to address the problem. The first is the United Nations Economic Commission for Europe Long Range Transboundary Air Pollution (LRTAP) Convention, signed in 1979. Under the LRTAP Convention, protocols with specific timetables for emission reductions have been established for SO2, nitrogen oxides (NOx) and volatile organic compounds (VOCs). Task forces are developing protocols for heavy metals and organochlorines. The second is the Canada-USA Great Lakes Water Quality Agreement, signed in 1978. Amendments made in 1987 recognized the importance of atmospheric deposition of toxic substances to the lakes, calling for research, monitoring, and control of such deposition. Finally, the Canada-USA Air Quality Agreement, signed in 1991, provides a framework for developing obligations needed to address transboundary air pollution problems. It includes commitments to reduce levels of SO2 and NOx. A bilateral committee has been established to assist in implementing this agreement. 7 refs

  12. Proceedings of the 2{sup nd} international conference on transport, atmosphere and climate (TAC-2)

    Energy Technology Data Exchange (ETDEWEB)

    Sausen, Robert; Blum, Anja (eds.) [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Velthoven, Peter F.J. van [Koninklijk Nederlands Meteorologisch Institut, De Bilt (Netherlands); Bruening, Claus [European Commission, DG Research, Directorate Environment, Brussels (Belgium)

    2010-08-15

    This volume collects oral and poster contributions to the '2nd International Conference on Transport, Atmosphere and Climate (TAC-2)' held in Aachen and Maastricht, 2009. With the objective of updating our knowledge on the impacts of transport on the composition of the atmosphere and on climate, the TAC-2 conference covered all aspects of the impact of the different modes of transport (aviation, road transport, shipping etc.) on atmospheric chemistry, cloud physics, radiation and climate, in particular: Engine emissions (gaseous and particulate), emission scenarios and emission data bases for transport, near-field and plume processes, effective emissions, transport impact on the chemical composition of the atmosphere, transport impact on aerosols, contrails, contrail cirrus, ship tracks, indirect cloud effects (e.g., aerosol-cloud interaction), radiation forcing, impact on climate, metrics for measuring climate change and damage, mitigation of transport impacts by technological changes in vehicles and engines, mitigation of transport impacts by operational means. (orig.)

  13. Atmospheric drivers of storage water use in Scots pine

    Directory of Open Access Journals (Sweden)

    H. Verbeeck

    2007-02-01

    Full Text Available In this study we determined the microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L. growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow and – storage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May–18 October.

    Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation was the main driver of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed, mainly driven by vapour pressure deficit (VPD. During dry atmospheric conditions (high VPD storage water use was reduced. This reduction was disproportionally higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought.

    A third important factor was the tree water deficit. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storage compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water deficit.

  14. Modeling of transport in the two-dimensional atmospheric transport and kinetics codes SPHERNEW and TRACER

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, A.

    1976-07-23

    The report describes how transport by the wind is modeled in the 2-D atmospheric transport and chemical kinetics codes SPHERNEW and TRACER. The description includes the equations for transport by a specified velocity field, the eddy diffusion approximation for short-term fluctuations in the velocity, other simplifying approximations, the geometric grid, the difference equations, and the coefficient matrix of the grid. The assumption of a constant vertical density distribution was used to derive mass-consistent forms of the difference equations. These forms eliminate the instabilities and unrealistic solutions associated with specified wind fields which are not exactly mass-consistent. An option is allowed for variable weighting between central (second-order) and upstream (first-order) forms of the spatial differencing of the advection terms, to modulate phase and amplitude errors in the advection model.

  15. The Atmospheric Radionuclide Transport Model (ARTM) - Validation of a long-term atmospheric dispersion model

    Science.gov (United States)

    Hettrich, Sebastian; Wildermuth, Hans; Strobl, Christopher; Wenig, Mark

    2016-04-01

    In the last couple of years, the Atmospheric Radionuclide Transport Model (ARTM) has been developed by the German Federal Office for Radiation Protection (BfS) and the Society for Plant and Reactor Security (GRS). ARTM is an atmospheric dispersion model for continuous long-term releases of radionuclides into the atmosphere, based on the Lagrangian particle model. This model, developed in the first place as a more realistic replacement for the out-dated Gaussian plume models, is currently being optimised for further scientific purposes to study atmospheric dispersion in short-range scenarios. It includes a diagnostic wind field model, allows for the application of building structures and multiple sources (including linear, 2-and 3-dimensional source geometries), and considers orography and surface roughness. As an output it calculates the activity concentration, dry and wet deposition and can model also the radioactive decay of Rn-222. As such, ARTM requires to undergo an intense validation process. While for short-term and short-range models, which were mainly developed for examining nuclear accidents or explosions, a few measurement data-sets are available for validation, data-sets for validating long-term models are very sparse and the existing ones mostly prove to be not applicable for validation. Here we present a strategy for the validation of long-term Lagrangian particle models based on the work with ARTM. In our validation study, the first part we present is a comprehensive analysis of the model sensitivities on different parameters like e.g. (simulation grid size resolution, starting random number, amount of simulation particles, etc.). This study provides a good estimation for the uncertainties of the simulation results and consequently can be used to generate model outputs comparable to the available measurements data at various distances from the emission source. This comparison between measurement data from selected scenarios and simulation results

  16. Factors governing water condensation in the Martian atmosphere

    Science.gov (United States)

    Colburn, David S.; Pollack, J. B.; Haberle, Robert M.

    1988-01-01

    Modeling results are presented suggesting a diurnal condensation cycle at high altitudes at some seasons and latitudes. In a previous paper, the use of atmospheric optical depth measurements at the Viking lander site to show diurnal variability of water condensation at different seasons of the Mars year was described. Factors influencing the amount of condensation include latitude, season, atmospheric dust content and water vapor content at the observation site. A one-dimensional radiative-convective model is used herein based on the diabatic heating routines under development for the Mars General Circulation Model. The model predicts atmospheric temperature profiles at any latitude, season, time of day and dust load. From these profiles and an estimate of the water vapor, one can estimate the maximum occurring at an early morning hour (AM) and the minimum in the late afternoon (PM). Measured variations in the atmospheric optical density between AM and PM measurements were interpreted as differences in AM and PM condensation.

  17. The Use of Strontium-87/Strontium-86 Ratios to Measure Atmospheric Transport into Forested Watersheds

    Science.gov (United States)

    Graustein, William C.; Armstrong, Richard L.

    1983-01-01

    Strontium-87/strontium-86 ratios indicate the sources of strontium in samples of natural waters, vegetation, and soil material taken from watersheds in the Sangre de Cristo Mountains of New Mexico. More than 75 percent of the strontium in the vegetation is ultimately derived from atmospheric transport and less than 25 percent from the weathering of the underlying rock. Much of the airborne strontium enters the watersheds by impacting on coniferous foliage, but deciduous foliage apparently traps little, if any, strontium-bearing aerosol. The strontium and presumably other nutrients are continuously recycled in a nearly closed system consisting of upper soil horizons, forest litter, and the standing crop of vegetation.

  18. Understanding transport in model water desalination membranes

    Science.gov (United States)

    Chan, Edwin

    Polyamide based thin film composites represent the the state-of-the-art nanofiltration and reverse osmosis membranes used in water desalination. The performance of these membranes is enabled by the ultrathin (~100 nm) crosslinked polyamide film in facilitating the selective transport of water over salt ions. While these materials have been refined over the last several decades, understanding the relationships between polyamide structure and membrane performance remains a challenge because of the complex and heterogeneous nature of the polyamide film. In this contribution, we present our approach to addressing this challenge by studying the transport properties of model polyamide membranes synthesized via molecular layer-by-layer (mLbL) assembly. First, we demonstrate that mLbL can successfully construct polyamide membranes with well-defined nanoscale thickness and roughness using a variety of monomer formulations. Next, we present measurement tools for characterizing the network structure and transport of these model polyamide membranes. Specifically, we used X-ray and neutron scattering techniques to characterize their structure as well as a recently-developed indentation based poromechanics approach to extrapolate their water diffusion coefficient. Finally, we illustrate how these measurements can provide insight into the original problem by linking the key polyamide network properties, i.e. water-polyamide interaction parameter and characteristic network mesh size, to the membrane performance.

  19. A synthesis of atmospheric mercury depletion event chemistry linking atmosphere, snow and water

    Directory of Open Access Journals (Sweden)

    A. Steffen

    2007-07-01

    Full Text Available It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere; however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg. This phenomenon is termed atmospheric mercury depletion events (AMDEs and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review the history of Hg in Polar Regions, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the roles that the snow pack, oceans, fresh water and the sea ice play in the cycling of Hg are presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not

  20. Transport of tritium contamination to the atmosphere in an arid environment

    Science.gov (United States)

    Garcia, C.A.; Andraski, B.J.; Stonestrom, D.A.; Cooper, C.A.; Johnson, M.J.; Michel, R.L.; Wheatcraft, S.W.

    2009-01-01

    Soil-plant-atmosphere interactions strongly infl uence water movement in desert unsaturated zones, but litile is known about how such interactions aff ect atmospheric release of subsurface water-borne contaminants. This 2-yr study, performed at the U.S. Geological Survey's Amargosa Desert Research Site in southern Nevada, quantifi ed the magnitude and spatiotemporal variability of tritium (3H) transport from the shallow unsaturated zone to the atmosphere adjacent to a low-level radioactive waste (LLRW) facility. Tritium fl uxes were calculated as the product of 3H concentrations in water vapor and respective evaporation and transpiration water-vapor fl uxes. Quarterly measured 3H concentrations in soil water vapor and in leaf water of the dominant creosote-bush [Larrea tridentata (DC.) Coville] were spatially extrapolated and temporally interpolated to develop daily maps of contamination across the 0.76-km2 study area. Maximum plant and root-zone soil concentrations (4200 and 8700 Bq L-1, respectively) were measured 25 m from the LLRW facility boundary. Continuous evaporation was estimated using a Priestley-Taylor model and transpiration was computed as the diff erence between measured eddy-covariance evapotranspiration and estimated evaporation. The mean evaporation/transpiration ratio was 3:1. Tritium released from the study area ranged from 0.12 to 12 ??g d-1 and totaled 1.5 mg (8.2 ?? 1010 Bq) over 2 yr. Tritium fl ux variability was driven spatially by proximity to 3H source areas and temporally by changes in 3H concentrations and in the partitioning between evaporation and transpiration. Evapotranspiration removed and limited penetration of precipitation beneath native vegetation and fostered upward movement and release of 3H from below the root zone. ?? Soil Science Society of America.

  1. Diurnal to annual variations in the atmospheric water cycle

    OpenAIRE

    Ruane, Alexander C

    2007-01-01

    This dissertation examines aspects of diurnal to annual variability in the atmospheric water cycle in observations and global numerical weather prediction models. Investigations begin with an in-depth evaluation of variance at a single time scale, followed by a comprehensive analysis of a particular water cycle component, and finally a complete description of the balances and exchanges of water cycle components across time scales. Comparisons of global and regional reanalyses reveal ...

  2. Retrieving Atmospheric Precipitable Water Vapor Using Artificial Neural Network Approach

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2013-07-01

    Full Text Available Discussing of water vapor and its variation is the important issue for synoptic meteorology and meteorology. In physical Atmospheric, the moisture content of the earth atmosphere is one of the most important parameters, it is hard to represent water vapor because of its space-time variation. High-spectral resolution Atmospheric Infrared Sounder (AIRS data can be used to retrieve the small scale vertical structure of air temperature, which provided a more accurate and good initial field for the numerical forecasting and the large-scale weather analysis. This paper proposes an artificial neural network to retrieve the clear sky atmospheric radiation data from AIRS and comparing with the AIRS Level-2 standard product, and gain a good inversion results.

  3. Water loss from terrestrial planets with CO2-rich atmospheres

    International Nuclear Information System (INIS)

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO2 atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO2-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ∼270 W m–2 (global mean) unlikely to lose more than one Earth ocean of H2O over their lifetimes unless they lose all their atmospheric N2/CO2 early on. Because of the variability of H2O delivery during accretion, our results suggest that many 'Earth-like' exoplanets in the habitable zone may have ocean-covered surfaces, stable CO2/H2O-rich atmospheres, and high mean surface temperatures.

  4. Atmospheric transport and wet deposition of ammonium in North Carolina

    Science.gov (United States)

    Walker, John T.; Aneja, Viney P.; Dickey, David A.

    Wet deposition and transport analysis has been performed for ammonium (NH 4+) in North Carolina, USA. Multiple regression analysis is employed to model the temporal trend and seasonality in monthly volume-weighted mean NH 4+ concentrations in precipitation from 1983 to 1996 at six National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. A significant ( ppopulated network of swine and poultry operations. This trend is positively correlated with increasing ammonia (NH 3) emissions related to the vigorous growth of North Carolina's swine population since 1990, particularly in the state's Coastal Plain region. A source-receptor regression model, which utilizes weekly NH 4+ concentrations in precipitation in conjunction with boundary layer air mass back trajectories, is developed to statistically test for the influence of a particular NH 3 source region on NH 4+ concentrations at surrounding NADP/NTN sites for the years 1995-1996. NH 3 emissions from this source region, primarily evolving from swine and poultry operations, are found to increase NH 4+ concentration in precipitation at sites up to ≈80 km away. At the Scotland County (NC36) and Wake County (NC41) sites, mean NH 4+ concentrations show increases of at least 44% for weeks during which 25% or more back trajectories are influenced by this source region.

  5. OPERA: An Atmospheric Correction for Land and Water

    Science.gov (United States)

    Sterckx, Sindy; Knaeps, Els; Adriaensen, Stefan; Reusen, Ils; De Keukelaere, Liesbeth; Hunter, Peter; Giardino, Claudia; Odermatt, Daniel

    2015-12-01

    Atmospheric correction is one of the most important part of the pre-processing of satellite remotely sensed data used to retrieve bio-geophysical paramters. In this paper we present the scene and sensor generic atmospheric correction scheme ‘OPERA’ allowing to correct both land and water areas in the remote sensing image. OPERA can now be used to correct for atmospheric effects in scenes acquired by MERIS, Landsat-8, hyperspectral sensors and will be applicable to Sentinel-3 and Sentinel-2.

  6. Atmospheric effects on infrared measurements at ground level: Application to monitoring of transport infrastructures

    Science.gov (United States)

    Boucher, Vincent; Dumoulin, Jean

    2014-05-01

    Being able to perform easily non-invasive diagnostics for surveillance and monitoring of critical transport infrastructures is a major preoccupation of many technical offices. Among all the existing electromagnetic methods [1], long term thermal monitoring by uncooled infrared camera [2] is a promising technique due to its dissemination potential according to its low cost on the market. Nevertheless, Knowledge of environmental parameters during measurement in outdoor applications is required to carry out accurate measurement corrections induced by atmospheric effects at ground level. Particularly considering atmospheric effects and measurements in foggy conditions close as possible to those that can be encountered around transport infrastructures, both in visible and infrared spectra. In the present study, atmospheric effects are first addressed by using data base available in literature and modelling. Atmospheric attenuation by particles depends greatly of aerosols density, but when relative humidity increases, water vapor condenses onto the particulates suspended in the atmosphere. This condensed water increases the size of the aerosols and changes their composition and their effective refractive index. The resulting effect of the aerosols on the absorption and scattering of radiation will correspondingly be modified. In a first approach, we used aerosols size distributions derived from Shettle and Fenn [3] for urban area which could match some of experimental conditions encountered during trials on transport infrastructures opened to traffic. In order to calculate the influence of relative humidity on refractive index, the Hänel's model [4] could be used. The change in the particulate size is first related to relative humidity through dry particle radius, particle density and water activity. Once the wet aerosol particle size is found, the effective complex refractive index is the volume weighted average of the refractive indexes of the dry aerosol substance

  7. Mechanism of isotonic water transport in glands.

    Science.gov (United States)

    Ussing, H H; Eskesen, K

    1989-07-01

    Since water and electrolytes pass cell membranes via separate channels, there can be no interactions in the membranes, and osmotic interactions between water and solutes can be expressed as the product of solute flux, frictional coefficient of solute, and length of pathway. It becomes clear that isotonic transport via a cell is impossible. In glands, where cation-selective junctions impede anion flux between the cells, isotonic water transport is only possible if sodium, after having passed the junction, is reabsorbed in the acinus and returned to the serosal side. Thus it can be recycled via the cation-selective junction and exert its drag on water more than once. This hypothesis was tested on frog skin glands. Skins were mounted in flux chambers with identical Ringer solutions on both sides. Na channels of the principal cells were closed with amiloride in the outside solution, and secretion stimulated with noradrenaline in the inside solution. Influx and efflux of Na, K and Br (used as tracer for Cl) were measured on paired half-skins during the constant-secretion phase. Flux ratios for both Na and K were higher than expected for electrodiffusion, indicating outgoing solvent drag. Flux ratios for K were much higher than those for Na. This is an agreement with the concept that Na is reabsorbed in the acinus and K is not. Two independent expressions for the degree of sodium recycling are developed. Under all experimental conditions these expressions give values for the recycling which are in good agreement. PMID:2473601

  8. Water transport in graphene nano-channels

    DEFF Research Database (Denmark)

    Wagemann, Enrique; Oyarzua, Elton; Walther, J. H.

    The transport of water in nanopores is of both fundamental and practical interest. Graphene Channels (GCs) are potential building blocks for nanofluidic devices dueto their molecularly smooth walls and exceptional mechanical properties. Numerous studies have found a significant flow rate enhancem......The transport of water in nanopores is of both fundamental and practical interest. Graphene Channels (GCs) are potential building blocks for nanofluidic devices dueto their molecularly smooth walls and exceptional mechanical properties. Numerous studies have found a significant flow rate...... between the chirality of the graphene walls and the slip length has not been established. In this study, we perform non-equilibrium molecular dynamics simulations of water flow in single- and multi-walled GCs. We examine the influence on the flow rates of dissipating the viscous heat produced...... by connecting the thermostat to the water molecules, the CNT wall atoms or both of them. From the atomic trajectories, we compute the fluid flow rates in GCs with zig-zag and armchair walls, heights from 1 to 4 nm and different number of graphene layers on the walls. A relation between the chirality, slip...

  9. High-resolution terahertz atmospheric water vapor continuum measurements

    Science.gov (United States)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.

    2014-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum due to the large number of rotational and vibrational transitions of many molecules of interest. This region of the spectrum has particular utility for applications such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum are lacking. The water vapor continuum absorption is an excess absorption that is unaccounted for in resonant line spectrum simulations. Currently a semiempirical model is employed to account for this absorption, however more measurements are necessary to properly describe the continuum absorption in this region. Fourier Transform Spectroscopy measurements from previous work are enhanced with high-resolution broadband measurements in the atmospheric transmission window at 1.5THz. The transmission of broadband terahertz radiation through pure water vapor as well as air with varying relative humidity levels was recorded for multiple path lengths. The pure water vapor measurements provide accurate determination of the line broadening parameters and experimental measurements of the transition strengths of the lines in the frequency region. Also these measurements coupled with the atmospheric air measurements allow the water vapor continuum absorption to be independently identified at 1.5THz. Simulations from an atmospheric absorption model using parameters from the HITRAN database are compared with the current and previous experimental results.

  10. IASOA circumpolar observations in service for research of atmospheric transports into and out of the Arctic

    Science.gov (United States)

    Vihma, Timo; Uttal, Taneil; Walden, Von; Cox, Christopher; Starkweather, Sandy; Makshtas, Alexander; Key, Jeff

    2016-04-01

    The International Arctic Systems for Observing the Atmosphere (IASOA) is an International Polar Year legacy consortium that focuses on coordinating measurements of the Arctic atmosphere collected at ten observatories in the U.S., Canada, Russia, Norway, Finland, and Greenland. The IASOA data portal and collaboratory process support thematic expert groups that work towards common goals for utilizing interoperable data products across the observatories. In addition to detailed surface observations and upper-air radiosonde program, some of the IASOA observatories collect information on the vertical profiles of moisture, cloud boundaries, cloud water/ice contents, and aerosols using radars, lidars ceilometers and radiometers. Collectively the IASOA network provides a unique source of information that can be utilized in order to provide the best possible empirical estimates of the horizontal atmospheric transports of momentum, heat, moisture, cloud water, cloud ice, and aerosols into and out of the Arctic Ocean region. These can be used in turn to support the evaluation of atmospheric reanalyses, weather and climate models, and satellite remote sensing products, and subsequently studies on the interaction between the Arctic and lower latitudes including the role of mid- and low-latitude forcing on the Arctic amplification of climate warming and the effects of Arctic changes on mid-latitude weather and climate. In addition, the IASOA data are valuable for the evaluation of gridded products (reanalyses, models, and satellite data) with respect to Earth surface variables, such as snow depth, soil moisture, surface temperature, radiative fluxes, albedo, as well as turbulent fluxes of sensible heat, latent heat, CO2, and CH4. Evaluation of surface fluxes is a vital to complement the evaluation of horizontal transports. These together will yield a comprehensive assessment of the quality of available gridded products in representing atmospheric budgets of heat, moisture

  11. Atmospheric transport and radioactive contamination of the atmosphere and of the ground

    International Nuclear Information System (INIS)

    The basic contamination source as a result of the accident at the Chernobyl Atomic Power Plant was the radioactive cloud and the gas stream. Based on the analyses of atmospheric aerosol samples collected in the immediate vicinity of the reactor an enrichment in iodine and cesium radionuclides was found. The meteorological conditions which governed the dispersion of air masses in the area around the Station determined the basic zone of close-in radioactive fallout to the north-west and the north-east of the Station. The distribution of radiation levels on the ground, the change in the concentrations of source radionuclides, data concerning the radioactive contamination of rivers and water reservoirs and values for the plutonium contamination of soil and grass are presented in tables, graphs and maps

  12. Spaceborne lidar system for measurements of atmospheric water vapor and aerosols

    Science.gov (United States)

    Browell, E. V.; Ismail, S.; Mccormick, M. P.; Swissler, T. J.

    1985-01-01

    The inclusion of a differential absorption lidar (DIAL) system as part of the NASA Earth Observing System (EOS) is proposed. Functioning at 720 nm, the DIAL could provide atmospheric water vapor profiles in the troposphere and stratosphere, and provide data for characterizing the physical properties of clouds. The use of frequency doubling of the laser could also open a window on the 355 nm region, and thereby molecular density and temperature profiles. The date would be of use in studies of the global hydrological cycle, the global radiation balance, climate, meteorology, and atmospheric structure and transport phenomena.

  13. Modeling Atmospheric Emissions and Calculating Mortality Rates Associated with High Volume Hydraulic Fracturing Transportation

    Science.gov (United States)

    Mathews, Alyssa

    Emissions from the combustion of fossil fuels are a growing pollution concern throughout the global community, as they have been linked to numerous health issues. The freight transportation sector is a large source of these emissions and is expected to continue growing as globalization persists. Within the US, the expanding development of the natural gas industry is helping to support many industries and leading to increased transportation. The process of High Volume Hydraulic Fracturing (HVHF) is one of the newer advanced extraction techniques that is increasing natural gas and oil reserves dramatically within the US, however the technique is very resource intensive. HVHF requires large volumes of water and sand per well, which is primarily transported by trucks in rural areas. Trucks are also used to transport waste away from HVHF well sites. This study focused on the emissions generated from the transportation of HVHF materials to remote well sites, dispersion, and subsequent health impacts. The Geospatial Intermodal Freight Transport (GIFT) model was used in this analysis within ArcGIS to identify roadways with high volume traffic and emissions. High traffic road segments were used as emissions sources to determine the atmospheric dispersion of particulate matter using AERMOD, an EPA model that calculates geographic dispersion and concentrations of pollutants. Output from AERMOD was overlaid with census data to determine which communities may be impacted by increased emissions from HVHF transport. The anticipated number of mortalities within the impacted communities was calculated, and mortality rates from these additional emissions were computed to be 1 in 10 million people for a simulated truck fleet meeting stricter 2007 emission standards, representing a best case scenario. Mortality rates due to increased truck emissions from average, in-use vehicles, which represent a mixed age truck fleet, are expected to be higher (1 death per 341,000 people annually).

  14. Tritium in atmospheric precipitations and water systems of Belarus

    International Nuclear Information System (INIS)

    Experimental and literature data concerning analysis of tritium in atmospheric precipitation and natural waters of Belarus including the lakes near the Ignalina NPP are compared and analyzed. It is concluded that the maximum of the curve 'amount of the samples - their activity' is shifted to the higher activity in the period 1994-2000 in comparison with 1980-1989. This increasing of the concentration of tritium in water can not be explained definitely by the Chernobyl accident. Consumption of drinking water with maximum registered tritium concentration in natural waters (10 Bq/l) will produce accumulation of dose equal 1,3·10-3 of public permissible dose limit (authors)

  15. Electron transport analysis in water vapor

    Science.gov (United States)

    Kawaguchi, Satoru; Takahashi, Kazuhiro; Satoh, Kohki; Itoh, Hidenori

    2016-07-01

    A reliable set of electron collision cross sections for water vapor, including elastic, rotational, vibrational, and electronic excitation, electron attachment, and ionization cross sections, is estimated by the electron swarm method. In addition, anisotropic electron scattering for elastic and rotational excitation collisions is considered in the cross section set. Electron transport coefficients such as electron drift velocity, longitudinal diffusion coefficient, and effective ionization coefficient are calculated from the cross section set by Monte Carlo simulation in a wide range of E/N values, where E and N are the applied electric field and the number density of H2O molecules, respectively. The calculated transport coefficients are in good agreement with those measured. The obtained results confirm that the anisotropic electron scattering is important for the calculation at low E/N values. Furthermore, the cross section set assuming the isotropic electron scattering is proposed for practical use.

  16. Water activated doping and transport in multilayered germanane crystals

    International Nuclear Information System (INIS)

    The synthesis of germanane (GeH) has opened the door for covalently functionalizable 2D materials in electronics. Herein, we demonstrate that GeH can be electronically doped by incorporating stoichiometric equivalents of phosphorus dopant atoms into the CaGe2 precursor. The electronic properties of these doped materials show significant atmospheric sensitivity, and we observe a reduction in resistance by up to three orders of magnitude when doped samples are measured in water-containing atmospheres. This variation in resistance is a result of water activation of the phosphorus dopants. Transport measurements in different contact geometries show a significant anisotropy between in-plane and out-of-plane resistances, with a much larger out-of-plane resistance. These measurements along with finite element modeling results predict that the current distribution in top-contacted crystals is restricted to only the topmost, water activated crystal layers. Taken together, these results pave the way for future electronic and optoelectronic applications utilizing group IV graphane analogues. (paper)

  17. Soil water repellency affects production and transport of CO2 and CH4 in soil

    Science.gov (United States)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  18. Sources, transport and deposition of iron in the global atmosphere

    Directory of Open Access Journals (Sweden)

    R. Wang

    2015-03-01

    Full Text Available Atmospheric deposition of iron (Fe plays an important role in controlling oceanic primary productivity. However, the sources of Fe in the atmosphere are not well understood. In particular, the combustion sources of Fe and their deposition over oceans are not accounted for in current biogeochemical models of the carbon cycle. Here we used a mass-balance method to estimate the emissions of Fe from the combustion of fossil fuels and biomass by accounting for the Fe contents in fuel and the partitioning of Fe during combustion. The emissions of Fe attached to aerosols from combustion sources were estimated by particle size, and their uncertainties were quantified by a Monte Carlo simulation. The emissions of Fe from mineral sources were estimated using the latest soil mineralogical database to date. As a result, the total Fe emissions from combustion averaged for 1960–2007 were estimated to be 5.1 Tg yr−1 (90% confidence of 2.2 to 11.5. Of these emissions, 2, 33 and 65% were emitted in particles 1, 1–10 μm (PM1−10, and >10 μm (PM>10, respectively, compared to total Fe emissions from mineral sources of 41.0 Tg yr−1. For combustion sources, different temporal trends were found in fine and medium-to-coarse particles, with a notable increase in Fe emissions in PM1 and PM1−10 since 2000 due to a rapid increase from motor vehicles. These emissions have been introduced in a global 3-D transport model run at a spatial resolution of of 0.94° latitude by 1.28° longitude to evaluate our estimation of Fe emissions. The modelled Fe concentrations were compared to measurements at 825 sampling stations. The deviation between modelled and observed Fe concentrations attached to aerosols at the surface was within a factor of two at most sampling stations, and the deviation was within a factor of 1.5 at sampling stations dominated by combustion sources. We analyzed the relative contribution of combustion sources to total Fe concentrations over

  19. Sources, transport and deposition of iron in the global atmosphere

    Science.gov (United States)

    Wang, R.; Balkanski, Y.; Boucher, O.; Bopp, L.; Chappell, A.; Ciais, P.; Hauglustaine, D.; Peñuelas, J.; Tao, S.

    2015-06-01

    Atmospheric deposition of iron (Fe) plays an important role in controlling oceanic primary productivity. However, the sources of Fe in the atmosphere are not well understood. In particular, the combustion sources of Fe and the subsequent deposition to the oceans have been accounted for in only few ocean biogeochemical models of the carbon cycle. Here we used a mass-balance method to estimate the emissions of Fe from the combustion of fossil fuels and biomass by accounting for the Fe contents in fuel and the partitioning of Fe during combustion. The emissions of Fe attached to aerosols from combustion sources were estimated by particle size, and their uncertainties were quantified by a Monte Carlo simulation. The emissions of Fe from mineral sources were estimated using the latest soil mineralogical database to date. As a result, the total Fe emissions from combustion averaged for 1960-2007 were estimated to be 5.3 Tg yr-1 (90% confidence of 2.3 to 12.1). Of these emissions, 1, 27 and 72% were emitted in particles 10 μm (PM> 10), respectively, compared to a total Fe emission from mineral dust of 41.0 Tg yr-1 in a log-normal distribution with a mass median diameter of 2.5 μm and a geometric standard deviation of 2. For combustion sources, different temporal trends were found in fine and medium-to-coarse particles, with a notable increase in Fe emissions in PM1 since 2000 due to an increase in Fe emission from motor vehicles (from 0.008 to 0.0103 Tg yr-1 in 2000 and 2007, respectively). These emissions have been introduced in a global 3-D transport model run at a spatial resolution of 0.94° latitude by 1.28° longitude to evaluate our estimation of Fe emissions. The modelled Fe concentrations as monthly means were compared with the monthly (57 sites) or daily (768 sites) measured concentrations at a total of 825 sampling stations. The deviation between modelled and observed Fe concentrations attached to aerosols at the surface was within a factor of 2 at most

  20. Regional Atmospheric Transport Code for Hanford Emission Tracking, Version 2(RATCHET2)

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, James V.; Rishel, Jeremy P.

    2006-07-01

    This manual describes the atmospheric model and computer code for the Atmospheric Transport Module within SAC. The Atmospheric Transport Module, called RATCHET2, calculates the time-integrated air concentration and surface deposition of airborne contaminants to the soil. The RATCHET2 code is an adaptation of the Regional Atmospheric Transport Code for Hanford Emissions Tracking (RATCHET). The original RATCHET code was developed to perform the atmospheric transport for the Hanford Environmental Dose Reconstruction Project. Fundamentally, the two sets of codes are identical; no capabilities have been deleted from the original version of RATCHET. Most modifications are generally limited to revision of the run-specification file to streamline the simulation process for SAC.

  1. Global modelling of the early Martian climate under a denser CO2 atmosphere: Water cycle and ice evolution

    OpenAIRE

    Wordsworth, R.; Forget, F.; Millour, E.; Head, J.; Madeleine, J.-B.; Charnay, B.

    2012-01-01

    We discuss 3D global simulations of the early Martian climate that we have performed assuming a faint young Sun and denser CO2 atmosphere. We include a self-consistent representation of the water cycle, with atmosphere-surface interactions, atmospheric transport, and the radiative effects of CO2 and H2O gas and clouds taken into account. We find that for atmospheric pressures greater than a fraction of a bar, the adiabatic cooling effect causes temperatures in the southern highland valley net...

  2. Atmospheric transport of persistent organic pollutants to aquatic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Agrell, Cecilia

    1999-04-01

    The load of persistent organic pollutants (POPs) is considered high in the Baltic ecosystem. The Baltic Sea spans over 12 latitudes and the regional differences in climate affect the behavior of POPs. Therefore spatial and temporal variability of the concentrations of POPs in air and precipitation within this area has been investigated at 16 (mostly rural) stations around the Baltic Sea between 1990-1993. In addition, the deposition of gaseous and particulate associated POPs to the Baltic Sea is estimated from empirical data. This atmospheric input of POPs is compared with the input from rivers. Additionally, data from Ross Island, Antarctica and Lake Kariba, Zimbabve, Africa is presented, and all results are discussed and explained using the `global fractionation hypothesis` as a framework. In the Baltic Sea, concentration of individual POPs in air were found to be influenced by their physical-chemical properties, ambient air temperature and location. A latitudinal gradient, with higher levels in the south was found for PCBs and the gradient was more pronounced for the low volatility congeners. As a result, the high volatility congeners in air increased in relative importance with latitude. Generally, PCB concentration increased with temperature, but slopes of the partial pressure in air versus reciprocal temperature were different between congeners and between stations. In general, the low volatility congeners were more temperature dependent than the high volatility PCB congeners. Steep slopes at a sampling location indicate that the concentration in air is largely determined by diffusive exchange with soils. Lack of a temperature dependence may be due to the influence of long-range transported air masses at remote sites and due to the episodic, or random nature of PCB sources at urban sites. The concentrations of individual congeners in precipitation were found to be influenced by atmospheric concentrations of PCBs, ambient temperature, precipitation volume and

  3. Atmospheric water uptake by an atacama desert shrub.

    Science.gov (United States)

    Mooney, H A; Gulmon, S L; Ehleringer, J; Rundel, P W

    1980-08-01

    Nolana mollis, a succulent-leaved shrub of the extreme coastal desert of Chile, has the capacity to condense water on its leaves out of unsaturated atmospheres, Metabolic energy would have to be expended to move this water either from the leaf surface directly to the mesophyll or, when dripped to the soil, from there into the roots. Because of the unusual aridity of its habitat and of the utilization of water-use-efficient metabolism by Nolana, at least during certain periods, such an energy expenditure could be effective. PMID:17821192

  4. Isotopic composition of atmospheric water vapor before and after the monsoon's end in the Nagqu River Basin

    Institute of Scientific and Technical Information of China (English)

    YU Wusheng; YAO Tandong; TIAN Lide; WANG Yu; YIN Changliang

    2005-01-01

    Atmospheric water vapor samples were collected in the Nagqu River Basin in the middle of Tibetan Plateau between August and October in 2004. Results show that there exist some fluctuations of the δ18O of atmospheric water vapor, especially before and after the monsoon's end. Moreover, the variety trend of the δ 18O of atmospheric water vapor inverse correlates with that of dew point. Precipitation events make an important effect upon the variation of δ18O of atmospheric water vapor. During the whole sampling period, the δ18O values of atmospheric water vapor are low while precipitation events occurred. The moisture origins also contribute to the variation of δ18O of atmospheric water vapor. The oceanic moisture transported by the southwest monsoon results in lower δ18O of atmospheric water vapor in the Nagqu River Basin. Compared with the influence of the oceanic moisture, the δ18O values, however, appear high resulting from the effect of the continental air mass in this region.

  5. Water loss from terrestrial planets with CO2-rich atmospheres

    CERN Document Server

    Wordsworth, Robin

    2013-01-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on atmospheric composition (CO2 and N2 levels), planetary mass, and external parameters (stellar spectrum, orbital distance and impacts). From coupled 1D climate and escape modeling, we show that CO2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO2 atmospheric partial pressures (0.1 to 1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but XUV/UV luminosity decreases, this places strong limits on moist...

  6. Pathways of PFOA to the Arctic: variabilities and contributions of oceanic currents and atmospheric transport and chemistry sources

    Directory of Open Access Journals (Sweden)

    I. Stemmler

    2010-05-01

    Full Text Available Perfluorooctanoic acid (PFOA and other perfluorinated compounds are industrial chemicals in use since decades which resist degradation in the environment and seem to accumulate in polar regions. Transport of PFOA was modeled using a spatially resolved global multicompartment model including fully coupled three-dimensional ocean and atmosphere general circulation models, and two-dimensional top soil, vegetation surfaces, and sea ice compartments. In addition to primary emissions, the formation of PFOA in the atmosphere from degradation of 8:2 fluorotelomer alcohol was included as a PFOA source. Oceanic transport, delivered 14.8±5.0 (8–23 t a−1 to the Arctic, strongly influenced by changes in water transport, which determined its interannual variability. This pathway constituted the dominant source of PFOA to the Arctic. Formation of PFOA in the atmosphere lead to episodic transport events (timescale of days into the Arctic with small spatial extent. Deposition in the polar region was found to be dominated by wet deposition over land, and shows maxima in boreal winter. The total atmospheric deposition of PFOA in the Arctic in the 1990s was ≈1 t a−1, much higher than previously estimated, and is dominated by primary emissions rather than secondarily formed.

  7. Pathways of PFOA to the Arctic: variabilities and contributions of oceanic currents and atmospheric transport and chemistry sources

    Science.gov (United States)

    Stemmler, I.; Lammel, G.

    2010-10-01

    Perfluorooctanoic acid (PFOA) and other perfluorinated compounds are industrial chemicals in use for decades which resist degradation in the environment and seem to accumulate in polar regions. Transport of PFOA was modeled using a spatially resolved global multicompartment model including fully coupled three-dimensional ocean and atmosphere general circulation models, and two-dimensional top soil, vegetation surfaces, and sea ice compartments. In addition to primary emissions, the formation of PFOA in the atmosphere from degradation of 8:2 fluorotelomer alcohol was included as a PFOA source. Oceanic transport, delivered 14.8±5.0 (8-23) t a-1 to the Arctic, strongly influenced by changes in water transport, which determined its interannual variability. This pathway constituted the dominant source of PFOA to the Arctic. Formation of PFOA in the atmosphere led to episodic transport events (timescale of days) into the Arctic with small spatial extent. Deposition in the polar region was found to be dominated by wet deposition over land, and shows maxima in boreal winter. The total atmospheric deposition of PFOA in the Arctic in the 1990s was ≈1 t a-1, much higher than previously estimated, and is dominated by primary emissions rather than secondary formation.

  8. Pathways of PFOA to the Arctic: variabilities and contributions of oceanic currents and atmospheric transport and chemistry sources

    Directory of Open Access Journals (Sweden)

    I. Stemmler

    2010-10-01

    Full Text Available Perfluorooctanoic acid (PFOA and other perfluorinated compounds are industrial chemicals in use for decades which resist degradation in the environment and seem to accumulate in polar regions. Transport of PFOA was modeled using a spatially resolved global multicompartment model including fully coupled three-dimensional ocean and atmosphere general circulation models, and two-dimensional top soil, vegetation surfaces, and sea ice compartments. In addition to primary emissions, the formation of PFOA in the atmosphere from degradation of 8:2 fluorotelomer alcohol was included as a PFOA source. Oceanic transport, delivered 14.8±5.0 (8–23 t a−1 to the Arctic, strongly influenced by changes in water transport, which determined its interannual variability. This pathway constituted the dominant source of PFOA to the Arctic. Formation of PFOA in the atmosphere led to episodic transport events (timescale of days into the Arctic with small spatial extent. Deposition in the polar region was found to be dominated by wet deposition over land, and shows maxima in boreal winter. The total atmospheric deposition of PFOA in the Arctic in the 1990s was ≈1 t a−1, much higher than previously estimated, and is dominated by primary emissions rather than secondary formation.

  9. Modeling UTLS water vapor: Transport/Chemistry interactions

    International Nuclear Information System (INIS)

    This thesis was initially meant to be a study on the impact on chemistry and climate from UTLS water vapor. However, the complexity of the UTLS water vapor and its recent changes turned out to be a challenge by it self. In the light of this, the overall motivation for the thesis became to study the processes controlling UTLS water vapor and its changes. Water vapor is the most important greenhouse gas, involved in important climate feedback loops. Thus, a good understanding of the chemical and dynamical behavior of water vapor in the atmosphere is crucial for understanding the climate changes in the last century. Additionally, parts of the work was motivated by the development of a coupled climate chemistry model based on the CAM3 model coupled with the Chemical Transport Model Oslo CTM2. The future work will be concentrated on the UTLS water vapor impact on chemistry and climate. We are currently studying long term trends in UTLS water vapor, focusing on identification of the different processes involved in the determination of such trends. The study is based on natural as well as anthropogenic climate forcings. The ongoing work on the development of a coupled climate chemistry model will continue within our group, in collaboration with Prof. Wei-Chyung Wang at the State University of New York, Albany. Valuable contacts with observational groups are established during the work on this thesis. These collaborations will be continued focusing on continuous model validation, as well as identification of trends and new features in UTLS water vapor, and other tracers in this region. (Author)

  10. ANALYTICAL MODELS OF EXOPLANETARY ATMOSPHERES. I. ATMOSPHERIC DYNAMICS VIA THE SHALLOW WATER SYSTEM

    International Nuclear Information System (INIS)

    Within the context of exoplanetary atmospheres, we present a comprehensive linear analysis of forced, damped, magnetized shallow water systems, exploring the effects of dimensionality, geometry (Cartesian, pseudo-spherical, and spherical), rotation, magnetic tension, and hydrodynamic and magnetic sources of friction. Across a broad range of conditions, we find that the key governing equation for atmospheres and quantum harmonic oscillators are identical, even when forcing (stellar irradiation), sources of friction (molecular viscosity, Rayleigh drag, and magnetic drag), and magnetic tension are included. The global atmospheric structure is largely controlled by a single key parameter that involves the Rossby and Prandtl numbers. This near-universality breaks down when either molecular viscosity or magnetic drag acts non-uniformly across latitude or a poloidal magnetic field is present, suggesting that these effects will introduce qualitative changes to the familiar chevron-shaped feature witnessed in simulations of atmospheric circulation. We also find that hydrodynamic and magnetic sources of friction have dissimilar phase signatures and affect the flow in fundamentally different ways, implying that using Rayleigh drag to mimic magnetic drag is inaccurate. We exhaustively lay down the theoretical formalism (dispersion relations, governing equations, and time-dependent wave solutions) for a broad suite of models. In all situations, we derive the steady state of an atmosphere, which is relevant to interpreting infrared phase and eclipse maps of exoplanetary atmospheres. We elucidate a pinching effect that confines the atmospheric structure to be near the equator. Our suite of analytical models may be used to develop decisively physical intuition and as a reference point for three-dimensional magnetohydrodynamic simulations of atmospheric circulation

  11. Model for radionuclide transport in running waters

    International Nuclear Information System (INIS)

    Two sites in Sweden are currently under investigation by SKB for their suitability as places for deep repository of radioactive waste, the Forsmark and Simpevarp/Laxemar area. As a part of the safety assessment, SKB has formulated a biosphere model with different sub-models for different parts of the ecosystem in order to be able to predict the dose to humans following a possible radionuclide discharge from a future deep repository. In this report, a new model concept describing radionuclide transport in streams is presented. The main difference from the previous model for running water used by SKB, where only dilution of the inflow of radionuclides was considered, is that the new model includes parameterizations also of the exchange processes present along the stream. This is done in order to be able to investigate the effect of the retention on the transport and to be able to estimate the resulting concentrations in the different parts of the system. The concentrations determined with this new model could later be used for order of magnitude predictions of the dose to humans. The presented model concept is divided in two parts, one hydraulic and one radionuclide transport model. The hydraulic model is used to determine the flow conditions in the stream channel and is based on the assumption of uniform flow and quasi-stationary conditions. The results from the hydraulic model are used in the radionuclide transport model where the concentration is determined in the different parts of the stream ecosystem. The exchange processes considered are exchange with the sediments due to diffusion, advective transport and sedimentation/resuspension and uptake of radionuclides in biota. Transport of both dissolved radionuclides and sorbed onto particulates is considered. Sorption kinetics in the stream water phase is implemented as the time scale of the residence time in the stream water probably is short in comparison to the time scale of the kinetic sorption. In the sediment

  12. Model for radionuclide transport in running waters

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Karin; Elert, Mark [Kemakta Konsult AB, Stockholm (Sweden)

    2005-11-15

    Two sites in Sweden are currently under investigation by SKB for their suitability as places for deep repository of radioactive waste, the Forsmark and Simpevarp/Laxemar area. As a part of the safety assessment, SKB has formulated a biosphere model with different sub-models for different parts of the ecosystem in order to be able to predict the dose to humans following a possible radionuclide discharge from a future deep repository. In this report, a new model concept describing radionuclide transport in streams is presented. The main difference from the previous model for running water used by SKB, where only dilution of the inflow of radionuclides was considered, is that the new model includes parameterizations also of the exchange processes present along the stream. This is done in order to be able to investigate the effect of the retention on the transport and to be able to estimate the resulting concentrations in the different parts of the system. The concentrations determined with this new model could later be used for order of magnitude predictions of the dose to humans. The presented model concept is divided in two parts, one hydraulic and one radionuclide transport model. The hydraulic model is used to determine the flow conditions in the stream channel and is based on the assumption of uniform flow and quasi-stationary conditions. The results from the hydraulic model are used in the radionuclide transport model where the concentration is determined in the different parts of the stream ecosystem. The exchange processes considered are exchange with the sediments due to diffusion, advective transport and sedimentation/resuspension and uptake of radionuclides in biota. Transport of both dissolved radionuclides and sorbed onto particulates is considered. Sorption kinetics in the stream water phase is implemented as the time scale of the residence time in the stream water probably is short in comparison to the time scale of the kinetic sorption. In the sediment

  13. ATMOSPHERIC MOISTURE CONDENSATION TO WATER RECOVERY BY HOME AIR CONDITIONERS

    Directory of Open Access Journals (Sweden)

    Amir Hossein Mahvi

    2013-01-01

    Full Text Available Earth’s atmosphere contains billion cubic meters of fresh water, which is considerable as a reliable water resource, especially in sultry areas. What is important in this context, how to extract the water, in an economic manner. In order to extract water from air conditioner, no need to spend any cost, because water produced as a by-product and trouble production. This cross-sectional study was conducted to evaluate the quantity and chemical quality of water obtained from Bandar Abbas air conditioners; at intervals beginning of March to early December of 2010. Sixty six samples were taken in cluster random plan. Bandar Abbas divided into four clusters; based on distance to shore and population density. Chemical tests which included: Turbidity, alkalinity, total hardness, Dissolved Solids (TDS and Electrical Conductivity (EC and quantity measurement were performed on them. Obtained water had slightly acidic pH, near to neutral range. Total dissolved solids, electrical conductivity, total hardness and alkalinity of extracted water were in low rate. Each air conditioner produced 36 liter per day averagely. Split types obtained more water to window air conditioners. With regard to some assumptions, approximately 4680 to 9360 cubic meter per day water is obtainable which is suitable for many municipal and industrial water applications.

  14. Atmospheric Transport During the Transport and Chemical Evolution over the Pacific TRACE-P Experiment

    Science.gov (United States)

    Fuelberg, Henry E.; Kiley, C. M.; Hannan, J. R.; Westberg, D. J.; Avery, M. A.; Newell, R. E.

    2003-01-01

    Atmospheric transport over the Pacific Basin is described during NASA's Transport and Chemical Evolution Over the Pacific Experiment (TRACE-P) that was conducted between February - April 2001. The mission included extensive chemical sampling from two aircraft based primarily in Hong Kong and Yokota Air Base, Japan. Meteorological conditions during TRACE-P changed rapidly due to the seasonal winter/spring transition and the decay of prolonged ENSO cold phase (La Nina) conditions. To document these changes, TRACE-P was divided into two halves, and mean flow patterns during each half are presented and discussed. Important circulation features are the semi-permanent Siberian anticyclone and transient middle latitude cyclones that form near eastern Asia and then move eastward over the northern Pacific. Five-day backward trajectories from the various flight tracks show that air sampled by the aircraft had been transported from a variety of locations. Some parcels remained over the tropical western North Pacific during the entire period, while other important origins were Southeast Asia, Africa, and central Asia. Patterns of satellite-derived precipitation and lightning are described. TRACE-P occurs during a neutral to weak La Nina period of relatively cold sea surface temperatures in the tropical Pacific. Compared to climatology, the TRACE-P period exhibits deep convection located west of its typical position; however, tropospheric flow patterns do not exhibit a strong La Nina signal. Circulation patterns during TRACE-P are found to be generally similar to those during NASA's PEM WEST-B mission that occurred in the same region during February - March 1994.

  15. Analytical Models of Exoplanetary Atmospheres: Atmospheric Dynamics via the Shallow Water System

    CERN Document Server

    Heng, Kevin

    2014-01-01

    Within the context of exoplanetary atmospheres, we present a comprehensive linear analysis of forced, damped, magnetized shallow water systems, exploring the effects of dimensionality, geometry (Cartesian, pseudo-spherical and spherical), rotation, magnetic tension and hydrodynamic and magnetic sources of friction. Across a broad range of conditions, we find that the key governing equation for atmospheres and quantum harmonic oscillators are identical, even when forcing (stellar irradiation), sources of friction (molecular viscosity, Rayleigh drag and magnetic drag) and magnetic tension are included. The global atmospheric structure is largely controlled by a single, key parameter that involves the Rossby and Prandtl numbers. This near-universality breaks down when either molecular viscosity or magnetic drag varies significantly across latitude or a poloidal magnetic field is present, suggesting that these effects will introduce qualitative changes to the familiar chevron-shaped feature witnessed in simulatio...

  16. Atmospheric correction for China's coastal water color remote sensing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The space satellite programs, such as CZCS/Nimbus- 7, VHRSR/FY - 1, OCTS/ADEOS and SeaWiFS/SeaStar, have demonstrated and proven that remote sensing is a powerful tool for understanding the spatial and temporal ocean color distribution. In general, there are two main techni cal keys in the processing ocean color satellite data. They are the atmospheric correction and the inver sion of water-leaving radiance into water constituents (such as chlorophyll, suspended material and yel low substance) quantitatively. The SeaWiFS (sea-viewing wide field-of-view sensor) atmospheric correc tion algorithm for China's coastal waters is discussed.First, the major advantages of SeaWiFS are introduced. Second, in view of the problems of the SeaDAS algorithm applying in China' s coastal waters, the local atmospheric correction algorithms are discussed and developed. Finally, the advantages of the loc al algorithms are presented by the compari son of the results from two different algorithms.

  17. Numerical Investigation of Laser Propulsion for Transport in Water Environment

    International Nuclear Information System (INIS)

    Problems that cumber the development of the laser propulsion in atmosphere and vacuum are discussed. Based on the theory of interaction between high-intensity laser and materials, as air and water, it is proved that transport in water environment can be impulsed by laser. The process of laser propulsion in water is investigated theoretically and numerically. It shows that not only the laser induced plasma shock wave, but also the laser induced bubble oscillation shock waves and the pressure induced by the collapsing bubble can be used. Many experimental results show that the theory and the numerical results are valid. The numerical result of the contribution of every propulsion source is given in percentage. And the maximum momentum coupling coefficient Cm is given. Laser propulsion in water environment can be applied in many fields. For example, it can provide highly controllable forces of the order of micro-Newton (μN) in microsystems, such as the MEMS (Micro-electromechanical Systems). It can be used as minimally invasive surgery tools of high temporal and spatial resolution. It can be used as the propulsion source in marine survey and exploitation.

  18. Complex source rate estimation for atmospheric transport and dispersion models

    International Nuclear Information System (INIS)

    The accuracy associated with assessing the environmental consequences of an accidental atmospheric release of radioactivity is highly dependent on our knowledge of the source release rate which is generally poorly known. This paper reports on a technique that integrates the radiological measurements with atmospheric dispersion modeling for more accurate source term estimation. We construct a minimum least squares methodology for solving the inverse problem with no a priori information about the source rate

  19. Transport of Ionizing Radiation in Terrestrial-like Exoplanet Atmospheres

    OpenAIRE

    Smith, David S.; Scalo, John; Wheeler, J. Craig

    2003-01-01

    (Abridged) The propagation of ionizing radiation through model atmospheres of terrestrial-like exoplanets is studied for a large range of column densities and incident photon energies using a Monte Carlo code we have developed to treat Compton scattering and photoabsorption. Incident spectra from parent star flares, supernovae, and gamma-ray bursts are modeled and compared to energetic particles in importance. We find that terrestrial-like exoplanets with atmospheres thinner than about 100 g ...

  20. Modeling of uncertainty in atmospheric transport system using hybrid method

    International Nuclear Information System (INIS)

    Atmospheric dispersion models are routinely used at nuclear and chemical plants to estimate exposure to the members of the public and occupational workers due to release of hazardous contaminants into the atmosphere. Atmospheric dispersion is a stochastic phenomenon and in general, the concentration of the contaminant estimated at a given time and at a predetermined location downwind of a source cannot be predicted precisely. Uncertainty in atmospheric dispersion model predictions is associated with: 'data' or 'parameter' uncertainty resulting from errors in the data used to execute and evaluate the model, uncertainties in empirical model parameters, and initial and boundary conditions; 'model' or 'structural' uncertainty arising from inaccurate treatment of dynamical and chemical processes, approximate numerical solutions, and internal model errors; and 'stochastic' uncertainty, which results from the turbulent nature of the atmosphere as well as from unpredictability of human activities related to emissions, The possibility theory based on fuzzy measure has been proposed in recent years as an alternative approach to address knowledge uncertainty of a model in situations where available information is too vague to represent the parameters statistically. The paper presents a novel approach (called Hybrid Method) to model knowledge uncertainty in a physical system by a combination of probabilistic and possibilistic representation of parametric uncertainties. As a case study, the proposed approach is applied for estimating the ground level concentration of hazardous contaminant in air due to atmospheric releases through the stack (chimney) of a nuclear plant. The application illustrates the potential of the proposed approach. (author)

  1. Daily European CO2 fluxes inferred by inversion of atmospheric transport

    Science.gov (United States)

    Bousquet, P.; Peylin, P.; Rayner, P.; Carouge, C.; Rivier, L.; Ciais, P.; Heinrich, P.; Hourdin, F.

    2002-12-01

    Continuous measurements of atmospheric CO2 over continental areas offer the potential to better understand the carbon fluxes between the terrestrial biosphere and the atmosphere. Up to now, most atmospheric inversions have provided monthly fluxes averaged over large sub continental regions. Refining space and time resolution of European fluxes calculated by inversion of atmospheric transport requires i) continuous CO2 measurements over Europe, ii) a high resolution transport model that can reproduce the variability of CO2 over continents and provide continuous response functions at model resolution, and iii) an updated inverse procedure that can use the increased associated information. We use here continuous CO2 measurements obtained through AEROCARB EU project (part of CARBOEUROPE cluster) for year 1998 at 10 continental stations to retrieve daily fluxes over Europe at model resolution with LMDZ transport model. LMDZ model is a global transport model with zoom and back-transport capabilities. A zoom was defined over Europe, with 0.4° maximum resolution. Back transport is based on self-adjoint property of atmospheric transport that makes it possible to get model daily response functions at model resolution and at low computing cost. In this talk, we present the new features of the inverse procedure and we detail the LMDZ back transport. First results obtained for daily European fluxes of the two last months of 1998 are presented and analysed. The question of retrieving fossil emissions from continuous measurements is also developed.

  2. Atmospheric absorption of terahertz radiation and water vapor continuum effects

    International Nuclear Information System (INIS)

    The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The transmission of broadband terahertz radiation from 0.300 to 1.500 THz was recorded for multiple path lengths and relative humidity levels. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions and available water vapor absorption data. The prediction code is able to separately model the different parts of atmospheric absorption for a range of experimental conditions. A variety of conditions were accurately modeled using this code including both self and foreign gas broadening for low and high water vapor pressures for many different measurement techniques. The intensity and location of the observed absorption lines were also in good agreement with spectral databases. However, there was a discrepancy between the resonant line spectrum simulation and the observed absorption spectrum in the atmospheric transmission windows caused by the continuum absorption. A small discrepancy remained even after using the best available data from the literature to account for the continuum absorption. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature. -- Highlights: •Broadband absorption measurements of water vapor were performed at 300–1500 GHz. •The absorption coefficient of water vapor was modeled and compared with data. •The air-broadened continuum coefficient for water vapor was determined. •The modeled absorption coefficient is presented for 10–90% humidity at 0–3 THz

  3. PCBs in the Arctic atmosphere: determining important driving forces using a global atmospheric transport model

    OpenAIRE

    Friedman, Carey L.; Selin, Noelle E

    2016-01-01

    We present a spatially and temporally resolved global atmospheric polychlorinated biphenyl (PCB) model, driven by meteorological data, that is skilled at simulating mean atmospheric PCB concentrations and seasonal cycles in the Northern Hemisphere midlatitudes and mean Arctic concentrations. However, the model does not capture the observed Arctic summer maximum in atmospheric PCBs. We use the model to estimate global budgets for seven PCB congeners, and we demonstrate that c...

  4. INVESTIGATION OF ATMOSPHERIC HUMIDITY TRANSPORT ON THE BASIS OF AEROLOGICAL MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    NYITRAI L.

    2015-03-01

    Full Text Available The global upper-air data base over the last 40 years is available by courtesy of College of Engineering and Applied Sciences at the University of Wyoming. Considering the fact, that in the atmospheric moisture transport between the oceans and the continents the humidity flow is much stronger towards the mainland than in the reverse direction, therefore it is reasonable to look for some correlation between the moisture transport and precipitation climate of the continents. For Europe, this is not easy because of the highly indented coastlines. According to laws of physics moisture transport influx to a (part of a continent i.e. through the border of a closed curve occurs as rain falling out in the water balance of the geographical area investigated. We are interested in quasi-stationary temporal changes showed by the stationary approach mentioned above that can be related to climate change. In Europe the precipitation regime of the rainy coast in Western Balkans can be described as a stationary approach, while the relationship between the moisture coming from the seas and the precipitation climate of Central and Eastern Europe in the past 40 years can be examined as a quasi-stationary process. This change in our region moves towards more frequent droughts having great economic influences, mainly in agriculture and hydrology. The aim of this study is to analyse the relationship between moisture convergence calculated by the radiosonde measurements and the precipitation climate of a selected area of land.

  5. Atmospheric emissions and long-range transport of persistent organic chemicals

    Directory of Open Access Journals (Sweden)

    Scheringer M.

    2010-12-01

    Full Text Available Persistent organic chemicals include several groups of halogenated compounds, such as polychlorinated biphenyls (PCBs, polybrominated diphenylethers (PBDEs, and polyfluorinated carboxylic acids (PFCAs. These chemicals remain for long times (years to decades in the environment and cycle between different media (air, water, sediment, soil, vegetation, etc.. The environmental distribution of this type of chemicals can conveniently be analyzed by multimedia models. Multimedia models consist of a set of coupled mass balance equations for the environmental media considered; they can be set up at various scales from local to global. Two applications of multimedia models to airborne chemicals are discussed in detail: the day-night cycle of PCBs measured in air near the surface, and the atmospheric long-range transport of volatile precursors of PFCAs, formation of PFCAs by oxidation of these precursors, and subsequent deposition of PFCAs to the surface in remote regions such as the Arctic.

  6. Short Communication: Atmospheric moisture transport, the bridge between ocean evaporation and Arctic ice melting

    Science.gov (United States)

    Gimeno, L.; Vázquez, M.; Nieto, R.; Trigo, R. M.

    2015-06-01

    If we could choose a region where the effects of global warming are likely to be pronounced and considerable, and at the same time one where the changes could affect the global climate in similarly asymmetric way with respect to other regions, this would unequivocally be the Arctic. The atmospheric branch of the hydrological cycle lies behind the linkages between the Arctic system and the global climate. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting the most significant changes in the Arctic region. This is because the transport of moisture from the extratropical regions to the Arctic has increased in recent decades, and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the assessing more objectively the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyze several recent results suggesting links between moisture transport and the extent of sea-ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnect ng results, using new information and insights. Among the many mechanisms that could be involved are hydrological (increased Arctic river discharges), radiative (increase of cloud cover and water vapour) and meteorological (increase in summer storms crossing the Arctic, or increments in precipitation).

  7. Short Communication: Atmospheric moisture transport, the bridge between ocean evaporation and Arctic ice melting

    Directory of Open Access Journals (Sweden)

    L. Gimeno

    2015-06-01

    Full Text Available If we could choose a region where the effects of global warming are likely to be pronounced and considerable, and at the same time one where the changes could affect the global climate in similarly asymmetric way with respect to other regions, this would unequivocally be the Arctic. The atmospheric branch of the hydrological cycle lies behind the linkages between the Arctic system and the global climate. Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting the most significant changes in the Arctic region. This is because the transport of moisture from the extratropical regions to the Arctic has increased in recent decades, and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the assessing more objectively the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyze several recent results suggesting links between moisture transport and the extent of sea-ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnect ng results, using new information and insights. Among the many mechanisms that could be involved are hydrological (increased Arctic river discharges, radiative (increase of cloud cover and water vapour and meteorological (increase in summer storms crossing the Arctic, or increments in precipitation.

  8. Ecological aspects of water coal fuel transportation and application

    Directory of Open Access Journals (Sweden)

    Anna SHVORNIKOVA

    2010-01-01

    Full Text Available This paper deals with the aspects of influence of transportation process and burning of water coal fuel on an ecological condition of environment. Also mathematical dependences between coal ash level and power consumption for transportation are presented.

  9. Atmospheric transport of persistent semi-volatile organic chemicals to the Arctic and cold condensation at the mid-troposphere – Part 1: 2-D modeling in mean atmosphere

    Directory of Open Access Journals (Sweden)

    J. Ma

    2010-01-01

    Full Text Available In the first part of this study for revisiting the cold condensation effect on global distribution of semi-volatile organic chemicals (SVOCs, the atmospheric transport of SVOCs to the Arctic at the mid-troposphere in a mean meridional atmospheric circulation over Northern Hemisphere was simulated by a two-dimensional atmospheric transport model. Results show that under the mean meridional atmosphere the long-range atmospheric transport of SVOCs from warm latitudes to the Arctic occurs primarily at the mid-troposphere. Accordingly, the cold condensation of the chemicals is likely also to take place at the mid-troposphere over a source region of the chemicals in warm low latitudes. We demonstrate that the temperature dependent vapour pressure and atmospheric degradation rate of SVOCs exhibit similarities between lower atmosphere over the Arctic and the mid-troposphere over a tropical region. Frequent occurrence of atmospheric ascending motion and convection over warm latitudes carry the chemicals to a higher altitude where some of these chemicals may condense/partition to particle or aqueous phase through the interaction with atmospheric aerosols, cloud water droplets and ice particles, and become more persistence in the lower temperatures. Stronger winds at the mid-troposphere then convey the condensed chemicals to the Arctic where they are brought down to the surface by large-scale descending motion and wet deposition. Using calculated water droplet-air partitioning coefficient of several persistent organic semi-volatile chemicals under a mean air temperature profile from the equator to the North Pole we propose that clouds are likely important sorbing media for SVOCs and pathway of the cold condensation effect and poleward atmospheric transport. The role of deposition and atmospheric descending motion in the cold condensation effect over the Arctic was also discussed.

  10. Transport of Ionizing Radiation in Terrestrial-like Exoplanet Atmospheres

    CERN Document Server

    Smith, D S; Wheeler, J C; Smith, David S.; Scalo, John

    2003-01-01

    (Abridged) Propagation of ionizing radiation, as from parent star flares, supernovae, or gamma-ray bursts, is studied for a suite of simple model atmospheres of terrestrial-like exoplanets covering a large range of column densities and incident photon energies. We developed a Monte Carlo code to treat the Compton scattering and photoabsorption. Atmospheres thinner than about 100 g cm^-2 transmit a significant fraction of incident gamma-rays, but even the thinnest atmospheres are essentially opaque to X-rays below about 30 keV. For thicker atmospheres, the incident ionizing radiation is efficiently blocked, but most of the incident energy is redistributed via secondary electron excitation into diffuse UV and visible aurora-like emission, increasing the atmospheric transmission by many orders of magnitude; in some cases the transmission can be up to 10%, depending on the intervening UV opacity. For Earth, between 2 x 10^-3 and 4 x 10^-2 of the incident flux reaches the ground in the 200-320 nm range, depending ...

  11. Investigations into the long-distance atmospheric transport in Central Europe using Rn-222

    International Nuclear Information System (INIS)

    An measuring network was used to determine the atmospheric Rn-222 content in Central Europe (Northern and Southern Germany, Poland). Rn-222 is to serve as tracer for the long-distance atmospheric transport in central Europe. For several areas, an average Rn-222 flux density was found. The radon source 'continent' and the soil as radon source have been taken into account. (DG)

  12. Mercury from combustion sources: a review of the chemical species emitted and their transport in the atmosphere

    International Nuclear Information System (INIS)

    Different species of mercury have different physical/chemical properties and thus behave quite differentially in air pollution control equipment and in the atmosphere. In general, emission of mercury from coal combustion sources are approximately 20-50% elemental mercury (Hg0) and 50-80% divalent mercury (Hg(II)), which may be predominantly HgCl2. Emissions of mercury from waste incinerators are approximately 10-20% Hg0 and 75-85% Hg(II). The partitioning of mercury in flue gas between the elemental and divalent forms may be dependent on the concentration of particulate carbon, HCl and other pollutants in the stack emissions. The emission of mercury from combustion facilities depends on the species in the exhaust stream and the type of air pollution control equipment used at the source. Air pollution control equipment for mercury removal at combustion facilities includes activated carbon injection, sodium sulfide injection and wet lime/limestone flue gas desulfurization. White Hg(II) is water-soluble and may be removed form the atmosphere by wet and dry deposition close to the combustion sources, the combination of a high vapor pressure and low water-solubility facilitate the long-range transport of Hg0 in the atmosphere. Background mercury in the atmosphere is predominantly Hg0. Elemental mercury is eventually removed from the atmosphere by dry deposition onto surfaces and by wet deposition after oxidation to water-soluble, divalent mercury. 62 refs., 2 figs., 1 tab

  13. High-Accuracy Spectral Lines for Radiation Transport in Stellar Atmospheres

    OpenAIRE

    Amit R. Sharma; Braams, Bastiaan J.; Bowman, Joel M.; Robert Warmbier; Ralf Schneider; Hauschildt, Peter H.

    2008-01-01

    The theory of radiative transfer is an important element for the understanding of the spectral signature and physical structure of stellar atmosphere. PHOENIX1 is a such, very general non-Local Thermodynamic Equilibrium(NLTE) stellar atmosphere computer code which can handle very large model atoms/molecules as well as line blanketing by hundreds of millions of atomic and molecular lines. The code is used to compute model atmospheres and synthetic spectra (solution of the radiative transport e...

  14. Water flow and solute transport in floating fen root mats

    Science.gov (United States)

    Stofberg, Sija F.; EATM van der Zee, Sjoerd

    2015-04-01

    Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to

  15. Liquid water on Mars - An energy balance climate model for CO2/H2O atmospheres

    Science.gov (United States)

    Hoffert, M. I.; Callegari, A. J.; Hsieh, C. T.; Ziegler, W.

    1981-01-01

    A simple climatic model is developed for a Mars atmosphere containing CO2 and sufficient liquid water to account for the observed hydrologic surface features by the existence of a CO2/H2O greenhouse effect. A latitude-resolved climate model originally devised for terrestrial climate studies is applied to Martian conditions, with the difference between absorbed solar flux and emitted long-wave flux to space per unit area attributed to the divergence of the meridional heat flux and the poleward heat flux assumed to equal the atmospheric eddy heat flux. The global mean energy balance is calculated as a function of atmospheric pressure to assess the CO2/H2O greenhouse liquid water hypothesis, and some latitude-resolved cases are examined in detail in order to clarify the role of atmospheric transport and temperature-albedo feedback. It is shown that the combined CO2/H2O greenhouse at plausible early surface pressures may account for climates hot enough to support a hydrological cycle and running water at present-day insolation and visible albedo levels.

  16. Transport of terrestrial atmospheric gases to the moon

    Science.gov (United States)

    Hills, H. K.; Freeman, J. W.

    1978-01-01

    The suprathermal Ion Detector Experiment instruments on the lunar surface have identified fluxes of ions which may be different from the solar wind both in elemental and in isotopic abundances. At present, only O/+/ is (tentatively) identified, but the mechanism operates to produce ions at the moon which have their origin in the earth's atmosphere. Consequently, the 'solar wind' component of the surface-correlated gases is effectively a combination of terrestrial atmospheric ions and the actual solar wind. The results differ from solar wind results if the terrestrial ion abundances strongly differ from those of the solar wind.

  17. Thermal shallow water models of geostrophic turbulence in Jovian atmospheres

    International Nuclear Information System (INIS)

    Conventional shallow water theory successfully reproduces many key features of the Jovian atmosphere: a mixture of coherent vortices and stable, large-scale, zonal jets whose amplitude decreases with distance from the equator. However, both freely decaying and forced-dissipative simulations of the shallow water equations in Jovian parameter regimes invariably yield retrograde equatorial jets, while Jupiter itself has a strong prograde equatorial jet. Simulations by Scott and Polvani [“Equatorial superrotation in shallow atmospheres,” Geophys. Res. Lett. 35, L24202 (2008)] have produced prograde equatorial jets through the addition of a model for radiative relaxation in the shallow water height equation. However, their model does not conserve mass or momentum in the active layer, and produces mid-latitude jets much weaker than the equatorial jet. We present the thermal shallow water equations as an alternative model for Jovian atmospheres. These equations permit horizontal variations in the thermodynamic properties of the fluid within the active layer. We incorporate a radiative relaxation term in the separate temperature equation, leaving the mass and momentum conservation equations untouched. Simulations of this model in the Jovian regime yield a strong prograde equatorial jet, and larger amplitude mid-latitude jets than the Scott and Polvani model. For both models, the slope of the non-zonal energy spectra is consistent with the classic Kolmogorov scaling, and the slope of the zonal energy spectra is consistent with the much steeper spectrum observed for Jupiter. We also perform simulations of the thermal shallow water equations for Neptunian parameter values, with a radiative relaxation time scale calculated for the same 25 mbar pressure level we used for Jupiter. These Neptunian simulations reproduce the broad, retrograde equatorial jet and prograde mid-latitude jets seen in observations. The much longer radiative time scale for the colder planet Neptune

  18. Thermal shallow water models of geostrophic turbulence in Jovian atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Warneford, Emma S., E-mail: emma.warneford@maths.ox.ac.uk; Dellar, Paul J., E-mail: dellar@maths.ox.ac.uk [OCIAM, Mathematical Institute, University of Oxford, Radcliffe Observatory Quarter, Oxford OX2 6GG (United Kingdom)

    2014-01-15

    Conventional shallow water theory successfully reproduces many key features of the Jovian atmosphere: a mixture of coherent vortices and stable, large-scale, zonal jets whose amplitude decreases with distance from the equator. However, both freely decaying and forced-dissipative simulations of the shallow water equations in Jovian parameter regimes invariably yield retrograde equatorial jets, while Jupiter itself has a strong prograde equatorial jet. Simulations by Scott and Polvani [“Equatorial superrotation in shallow atmospheres,” Geophys. Res. Lett. 35, L24202 (2008)] have produced prograde equatorial jets through the addition of a model for radiative relaxation in the shallow water height equation. However, their model does not conserve mass or momentum in the active layer, and produces mid-latitude jets much weaker than the equatorial jet. We present the thermal shallow water equations as an alternative model for Jovian atmospheres. These equations permit horizontal variations in the thermodynamic properties of the fluid within the active layer. We incorporate a radiative relaxation term in the separate temperature equation, leaving the mass and momentum conservation equations untouched. Simulations of this model in the Jovian regime yield a strong prograde equatorial jet, and larger amplitude mid-latitude jets than the Scott and Polvani model. For both models, the slope of the non-zonal energy spectra is consistent with the classic Kolmogorov scaling, and the slope of the zonal energy spectra is consistent with the much steeper spectrum observed for Jupiter. We also perform simulations of the thermal shallow water equations for Neptunian parameter values, with a radiative relaxation time scale calculated for the same 25 mbar pressure level we used for Jupiter. These Neptunian simulations reproduce the broad, retrograde equatorial jet and prograde mid-latitude jets seen in observations. The much longer radiative time scale for the colder planet Neptune

  19. Water transport between CNS compartments: contributions of aquaporins and cotransporters

    DEFF Research Database (Denmark)

    MacAulay, N; Zeuthen, T

    2010-01-01

    hydrocephalus. The molecular pathways by which water molecules cross the cell membranes of the brain are not well-understood, although the discovery of aquaporin 4 (AQP4) in the brain improved our understanding of some of these transport processes, particularly under pathological conditions. In the present...... review we introduce another family of transport proteins as water transporters, namely the cotransporters and the glucose uniport GLUT1. In direct contrast to the aquaporins, these proteins have an inherent ability to transport water against an osmotic gradient. Some of them may also function as water...

  20. Quantifying atmospheric transport, chemistry, and mixing using a new trajectory-box model and a global atmospheric-chemistry GCM

    Directory of Open Access Journals (Sweden)

    H. Riede

    2009-12-01

    Full Text Available We present a novel method for the quantification of transport, chemistry, and mixing along atmospheric trajectories based on a consistent model hierarchy. The hierarchy consists of the new atmospheric-chemistry trajectory-box model CAABA/MJT and the three-dimensional (3-D global ECHAM/MESSy atmospheric-chemistry (EMAC general circulation model. CAABA/MJT employs the atmospheric box model CAABA in a configuration using the atmospheric-chemistry submodel MECCA (M, the photochemistry submodel JVAL (J, and the new trajectory submodel TRAJECT (T, to simulate chemistry along atmospheric trajectories, which are provided offline. With the same chemistry submodels coupled to the 3-D EMAC model and consistent initial conditions and physical parameters, a unique consistency between the two models is achieved. Since only mixing processes within the 3-D model are excluded from the model consistency, comparisons of results from the two models allow to separate and quantify contributions of transport, chemistry, and mixing along the trajectory pathways. Consistency of transport between the trajectory-box model CAABA/MJT and the 3-D EMAC model is achieved via calculation of kinematic trajectories based on 3-D wind fields from EMAC using the trajectory model LAGRANTO. The combination of the trajectory-box model CAABA/MJT and the trajectory model LAGRANTO can be considered as a Lagrangian chemistry-transport model (CTM moving isolated air parcels. The procedure for obtaining the necessary statistical basis for the quantification method is described as well as the comprehensive diagnostics with respect to chemistry.

    The quantification method presented here allows to investigate the characteristics of transport, chemistry, and mixing in a grid-based 3-D model. The analysis of chemical processes within the trajectory-box model CAABA/MJT is easily extendable to include, for example, the impact of different transport pathways or of mixing processes onto

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

    OpenAIRE

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

    2014-01-01

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

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

    OpenAIRE

    Righi, Mattia; Hendricks, Johannes; Sausen, Robert

    2015-01-01

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

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

    CERN Document Server

    Schröder, Alexander; Lunkeit, Frank

    2014-01-01

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

  4. The seasonal and global behavior of water vapor in the Mars atmosphere - Complete global results of the Viking atmospheric water detector experiment

    Science.gov (United States)

    Jakosky, B. M.; Farmer, C. B.

    1982-01-01

    A key question regarding the evolution of Mars is related to the behavior of its volatiles. The present investigation is concerned with the global and seasonal abundances of water vapor in the Mars atmosphere as mapped by the Viking Mars Atmospheric Water Detector (MAWD) instrument for almost 1-1/2 Martian years from June 1976 to April 1979. Attention is given to the implications of the observed variations for determining the relative importance of those processes which may be controlling the vapor cycle on a seasonal basis. The processes considered include buffering of the atmosphere water by a surface or subsurface reservior of ground ice, physically adsorbed water, or chemically bound water. Other processes are related to the supply of water from the residual or seasonal north polar ice cap, the redistribution of the vapor resulting from atmospheric circulation, and control of the vapor holding capacity of the atmosphere by the local atmospheric temperatures.

  5. Data Assimilation and Transport Modeling in Terrestrial and Planetary Atmospheres

    Science.gov (United States)

    Houben, Howard C.; Young, Richard E. (Technical Monitor)

    2002-01-01

    Data assimilation is a blanket term used to describe a number of techniques for retrieving important physical parameters from observational data, subject to constraints imposed by prior knowledge (such as, in the case of meteorology, the primitive equations that govern atmospheric motion). Since these newly developed methods make efficient use of computational resources, they are of great importance in the interpretation of the voluminous datasets that are now produced by satellite missions. As proposed, these techniques have been applied to the study of the Martian and terrestrial atmospheres based on available satellite observations. In addition, a sophisticated hydrodynamic model (non-hydrostatic, and therefore applicable to the study of the interiors of the giant planets) has also been developed and successfully applied to the study of tidally induced motions in Jupiter.

  6. Water flow and nutrient transport in a layered silt loam.

    OpenAIRE

    Vos

    1997-01-01

    Theory, numerical models, and field and laboratory measurements are used to describe and predict water flow and nutrient transport in a layered silt loam soil. One- and two-dimensional models based on the Darcy equation for water flow and the convection-dispersion equation for solute transport are evaluated. Pressure heads simulated with the one-dimensional water balance model SWATRE are too large. The two-dimensional SWMS_2D model simulates water flow well for the winter leaching periods. Th...

  7. The Economics of Bulk Water Transport in Southern California

    OpenAIRE

    Andrew Hodges; Kristiana Hansen; Donald McLeod

    2014-01-01

    Municipalities often face increasing demand for limited water supplies with few available alternative sources. Under some circumstances, bulk water transport may offer a viable alternative. This case study documents a hypothetical transfer between a water utility district in northern California and urban communities located on the coast of central and southern California. We compare bulk water transport costs to those of constructing a new desalination facility, which is the current plan of ...

  8. Collisions, magnetization, and transport coefficients in the lower solar atmosphere

    CERN Document Server

    Vranjes, J

    2013-01-01

    The lower solar atmosphere is an intrinsically multi-component and collisional environment with electron and proton collision frequencies in the range $10^{8}-10^{10}$ Hz, which may be considerably higher than the gyro-frequencies for both species. We aim to provide a reliable quantitative set of data for collision frequencies, magnetization, viscosity, and thermal conductivity for the most important species in the lower solar atmosphere. Having such data at hand is essential for any modeling that is aimed at describing realistic properties of the considered environment. We describe the altitude dependence of the parameters and the different physics of collisions between charged species, and between charged and neutrals species. Regions of dominance of each type of collisions are clearly identified. We determine the layers within which either electrons or ions or both are unmagnetized. Protons are shown to be un-magnetized in the lower atmosphere in a layer that is at least 1000 km thick even for a kilo-Gauss...

  9. Latitudinal distribution of the sources and sinks of atmospheric carbon dioxide derived from surface observations and an atmospheric transport model

    Science.gov (United States)

    Tans, Pieter P.; Conway, Thomas J.; Nakazawa, Takakiyo

    1989-04-01

    Determination of the present global budget of atmospheric carbon dioxide (CO2) from the small and persistent concentration gradients that exist in the atmosphere is discussed. The CO2 concentration at any site results from a combination of two factors: local sources or sinks and long-range transport. To separate these two effects, an atmospheric transport model is needed. The extensive sets of global CO2 measurements of the National Oceanic and Atmospheric Administration's (NOAA) Geophysical Monitoring for Climatic Change (GMCC) division and of the Upper Atmosphere and Space Research Laboratory of Tohoku University are combined with a two-dimensional transport model to derive, in an "inverse" calculation, the latitudinal and seasonal distributions of sources and sinks of CO2 necessary to reproduce the observed concentrations. The model transport parameters were previously derived from a three-dimensional general circulation model. It is found that the southern oceans are a sink of carbon of 0.8-1.5 Gt yr-1 (1 Gt equals 1015g) and that the equatorial areas are a source to the atmosphere of 1.4-2.8 Gt yr-1. Tropical deforestation as a major source of CO2 must be smaller than that because the oceans account for a significant part of the equatorial flux. There seems to be significant seasonality in the sources and sinks of CO2, both in the tropics and in the southern oceans. The seasonal net ecosystem production north of 25°N is found to be 6.2-8.2 Gt of carbon, but these estimates are probably somewhat too low. The source deduction problem is difficult to solve, especially for the middle and high latitudes in the northern hemisphere. This is due to a lack of observations over the continents, which occupy more than half of the global area at these latitudes and are the regions where the sources and sinks are most intense. Evidence is found in the results obtained for the GMCC and Tohoku data that the longitudinal variability of the data is large enough, even in

  10. The application of flux-form semi-Lagrangian transport scheme in a spectral atmosphere model

    Science.gov (United States)

    Wang, Xiaocong; Liu, Yimin; Wu, Guoxiong; Lin, Shian-Jiann; Bao, Qing

    2013-01-01

    A flux-form semi-Lagrangian transport scheme (FFSL) was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with less dissipation and dispersion, in comparison with other conventional schemes. Importantly, FFSL can automatically maintain the positive definition of the transported tracers, which was an underlying problem in the previous spectral composite method (SCM). To comprehensively investigate the impact of FFSL on GCM results, we conducted sensitive experiments. Three main improvements resulted: first, rainfall simulation in both distribution and intensity was notably improved, which led to an improvement in precipitation frequency. Second, the dry bias in the lower troposphere was significantly reduced compared with SCM simulations. Third, according to the Taylor diagram, the FFSL scheme yields simulations that are superior to those using the SCM: a higher correlation between model output and observation data was achieved with the FFSL scheme, especially for humidity in lower troposphere. However, the moist bias in the middle and upper troposphere was more pronounced with the FFSL scheme. This bias led to an over-simulation of precipitable water in comparison with reanalysis data. Possible explanations, as well as solutions, are discussed herein.

  11. Transfer of atmospheric tritiated water to foliage and fruit of crops

    International Nuclear Information System (INIS)

    Tritiated water (THO) released to the environment from the effluent streams of nuclear reactors may be easily assimilated by organisms through metabolic fixation following foliar interception of THO vapor. This study was initiated to characterize atmospheric THO exchange parameters in two crops agronomically important to eastern Washington, grape (Vitus vinifera) and alfalfa (Medicago sativa). Short-term exposures using atmospheric THO concentrations ranging from 458 to 1,300,900 pCi/m3 indicated no statistically significant concentration influences on THO exchange into the leaf tissue free-water (TFW) and organically bound tritium (OBT) of the leaves of either species. Long-term exposures indicated that equilibration of the leaf TFW with atmospheric THO concentrations occurred within 24 to 48 h for both species while equilibration of grape TFW appeared to take over 20 days. The rate of THO saturation of the foliage TFW appeared to be directly related to the stomatal resistance of the leaves and fruit. Desorption rates from both leaves and fruit were greater in the light than in the dark, again correlating with stomatal resistance. More than 90% of the absorbed THO was lost from the leaf TFW pool within 24 h following cessation of exposure for both species, while loss of THO from grape TFW and OBT pools was minimal. It appeared that more than 95 to 98% of the THO found in the TFW and OBT pools of the grape fruit was of atmospheric origin and not from transport from other parts of the plant

  12. K9 water searches: scent and scent transport considerations.

    Science.gov (United States)

    Osterkamp, Tom

    2011-07-01

    Increased use of water search dogs for detecting submerged bodies has created the need for a better understanding of scent emanating from the bodies and how it transits the water to the dog's nose. A review of recent literature identifies likely scent sources, potential scent transport processes, and research needs. Scent sources include gases in bubbles or dissolved in the water, liquids as buoyant plumes and droplets or dissolved in the water, and solids consisting of buoyant particulates with secretions, bacteria, and body fluids. Potential transport processes through the water include buoyancy, entrainment, and turbulence. Transport processes from the water surface into the air include volatilization and evaporation enhanced by bubble bursting, breaking waves, splashing, and wind spray. Implications for the use of water search dogs are examined. Observations of submerged, decomposing bodies are needed to quantify the physical and chemical characteristics of the scent and scent transport processes. PMID:21480897

  13. Moist convection and the vertical structure and water abundance of Jupiter's atmosphere

    Science.gov (United States)

    Del Genio, Anthony D.; Mcgrattan, Kevin B.

    1990-01-01

    The cumulative effects of an ensemble of moist convective plumes on a conditionally unstable atmosphere are predicted by a model of moist convection on Jupiter in which the heating/cooling and drying/moistening of the environment occur through (1) compensating subsidence, (2) detrainment of updraft air at cloud tops, and (3) the evaporation and melting of falling condensate. Parahydrogen is transported as a passive tracer. Pure moist convective, mixed moist-dry convective, and primarily dry convective regimes are possible, depending on the assumed deep-water abundance, efficiency of condensate evaporation, and initial temperature profile.

  14. Sources of dissolved mine drainage and atmospheric transported lead: A comparative case study in Japan and Sweden

    International Nuclear Information System (INIS)

    A comparative case study in Naganobori Japan and Falun Sweden of runoff water from copper mines shows that the water and its particulates, filtered with a cutoff of 0.45 μm, have different lead isotope ratios pointing to different origins for the lead. While the larger particles have a lead ratio indicative of the atmospheric anthropogenic pollution the soluble lead has that of the copper ores. The domestic atmospheric lead ratio in Japan is homogeneous and characteristic of emissions from the incineration of waste. Lead pollution transported from the Asian continent by westerly winds can be distinguished from the Japanese pollution by its more thorogenic lead ratios, in for example analyses of copper moss from Naganobori.

  15. Molecular mechanisms of water transport in the eye

    DEFF Research Database (Denmark)

    Hamann, Steffen; Hamann, Steffen Ellitsgaard

    2002-01-01

    general model for water transport in ocular epithelia. Some water-transporting membranes contain aquaporins, others do not. The ultrastructure is also variable among the cell layers and cannot be fitted into a general model. On the other hand, the direction of cotransport in symporters complies with the......The four major sites for ocular water transport, the corneal epithelium and endothelium, the ciliary epithelium, and the retinal pigment epithelium, are reviewed. The cornea has an inherent tendency to swell, which is counteracted by its two surface cell layers, the corneal epithelium and...... endothelium. The bilayered ciliary epithelium secretes the aqueous humor into the posterior chamber, and the retinal pigment epithelium transports water from the retinal to the choroidal site. For each epithelium, ion transport mechanisms are associated with fluid transport, but the exact molecular coupling...

  16. Water Vapor Tacers as Diagnostics of the Regional Atmospheric Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle, especially in North America where moisture transport and local evaporation are important sources of water for precipitation. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. All evaporative sources of water are accounted for by tracers, and the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The Geostationary Operational Environmental Satellites General Circulation Model (GEOS GCM) is used to simulate several summer periods to determine the source regions of precipitation for the United States and India. Using this methodology, a detailed analysis of the recycling of water, interannual variability of the sources of water and links to the Great Plains low-level jet and North American monsoon will be presented. Potential uses in GCM sensitivity studies, predictability studies and data assimilation especially regarding the North American monsoon and GEWEX America Prediction Project (GAPP) will be discussed.

  17. Habitability of waterworlds: runaway greenhouses, atmospheric expansion and multiple climate states of pure water atmospheres

    OpenAIRE

    Goldblatt, Colin

    2015-01-01

    There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds". I map these as a function of solar constant for planets ranging in size from Mars size to 10 Earth-mass. The states are: globally ice covered (Ts< 245K), cold and damp (270 < Ts< 290K), hot and moist (350< Ts< 550K) and very hot and dry (Ts< 900K). No stable climate exists for 290< Ts < 350K or 550 < Ts < 900K. The union of hot moist and cold damp climates describe the liquid ...

  18. Linking Hydrology and Atmospheric Sciences in Continental Water Dynamics Modeling

    Science.gov (United States)

    David, C. H.; Gochis, D. J.; Maidment, D. R.; Wilhelmi, O.

    2006-12-01

    Atmospheric observation and model output datasets as well as hydrologic datasets are increasingly becoming available on a continental scale. Although the availability of these datasets could allow large-scale water dynamics modeling, the different objects and semantics used in atmospheric science and hydrology set barriers to their interoperability. Recent work has demonstrated the feasibility for modeling terrestrial water dynamics for the continental United States of America. Continental water dynamics defines the interaction of the hydrosphere, the land surface and subsurface at spatial scales ranging from point to continent. The improved version of the National Hydrographic Dataset (NHDPlus, an integrated suite of geospatial datasets stored in a vector and raster GIS format) was used as hydrologic and elevation data input to the Noah community Land Surface Model, developed at NCAR. Noah was successfully run on a watershed in the Ohio River Basin with NHDPlus inputs. The use of NHDPlus as input data for Noah is a crucial improvement for community modeling efforts allowing users to by-pass much of the time consumed in Digital Elevation Model and hydrological network processing. Furthermore, the community Noah land surface model, in its hydrologically-enhanced configuration, is capable of providing flow inputs for a river dynamics model. Continued enhancement of Noah will, as a consequence, be beneficial to the atmospheric science community as well as to the hydrologic community. Ongoing research foci include using a diversity of weather drivers as an input to Noah, and investigation of how to use land surface model outputs for river forecasting, using both the ArcHydro and OpenMI frameworks.

  19. Atmospheric transport and dispersion modeling for the Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Radiation doses that may have resulted from operations at the Hanford Site are being estimated in the Hanford Environmental Dose Reconstruction (HEDR) Project. One of the project subtasks, atmospheric transport, is responsible for estimating the transport, diffusion and deposition of radionuclides released to the atmosphere. This report discusses modeling transport and diffusion in the atmospheric pathway. It is divided into three major sections. The first section of the report presents the atmospheric modeling approach selected following discussion with the Technical Steering Panel that directs the HEDR Project. In addition, the section discusses the selection of the MESOI/MESORAD suite of atmospheric dispersion models that form the basis for initial calculations and future model development. The second section of the report describes alternative modeling approaches that were considered. Emphasis is placed on the family of plume and puff models that are based on Gaussian solution to the diffusion equations. The final portion of the section describes the performance of various models. The third section of the report discusses factors that bear on the selection of an atmospheric transport modeling approach for HEDR. These factors, which include the physical setting of the Hanford Site and the available meteorological data, serve as constraints on model selection. Five appendices are included in the report. 39 refs., 4 figs., 2 tabs

  20. Modelling intercontinental transport of atmospheric sulphur in the northern hemisphere

    OpenAIRE

    Tarrasón, L; Iversen, T.

    2011-01-01

    Intercontinental exchange of sulphur in major parts of the northern hemisphere has been studied with a 3-dimensional Eulerian transport model that resolves regional scale variability. Model results for 1988 have been evaluated against daily observations of sulphur dioxide and particulate sulphate in Europe and North America and show that the model reproduces the episodic character of oxidised sulphur in air. Yearly averages agree with the observations within a factor of 2, at over 75% of the ...

  1. Water vapor measurement system in global atmospheric sampling program, appendix

    Science.gov (United States)

    Englund, D. R.; Dudzinski, T. J.

    1982-01-01

    The water vapor measurement system used in the NASA Global Atmospheric Sampling Program (GASP) is described. The system used a modified version of a commercially available dew/frostpoint hygrometer with a thermoelectrically cooled mirror sensor. The modifications extended the range of the hygrometer to enable air sample measurements with frostpoint temperatures down to -80 C at altitudes of 6 to 13 km. Other modifications were made to permit automatic, unattended operation in an aircraft environment. This report described the hygrometer, its integration with the GASP system, its calibration, and operational aspects including measurement errors. The estimated uncertainty of the dew/frostpoint measurements was + or - 1.7 Celsius.

  2. Transport of Water in Semicrystalline Block Copolymer Membranes

    Science.gov (United States)

    Hallinan, Daniel; Oparaji, Onyekachi

    Poly(styrene)-block-poly(ethylene oxide) (PS- b-PEO) is a semicrystalline block copolymer (BCP) with interesting properties. It is mechanically tough, amphiphilic, and has a polar phase. The mechanical toughness is due to the crystallinity of PEO and the high glass transition temperature of PS, as well as the morphological structure of the BCP. The polymer has high CO2, water, and salt solubility that derive from the polar PEO component. Potential applications include CO2 separation, water purification, and lithium air batteries. In all of the aforementioned applications, water transport is an important parameter. The presence of water can also affect thermal and mechanical properties. Water transport and thermal and mechanical properties of a lamellar PS- b-PEO copolymer have been measured as a function of water activity. Water transport can be affected by the heterogeneous nature of a semicrystalline BCP. Therefore, Fourier transform infrared - attenuated total reflectance (FTIR-ATR) spectroscopy has been employed, because water transport and polymer swelling can be measured simultaneously. The effect of BCP structure on transport has been investigated by comparing water transport in PS- b-PEO to a PEO homopolymer. The crystalline content of the PEO and the presence of glassy PS lamellae will be used to explain the transport results.

  3. Water Transport through Cohesion-Tension in Porous Structures

    Science.gov (United States)

    Kosaraju, Srinivas

    2015-11-01

    The predominant theory to explain water transport through plant xylem is the cohesion-tension theory. According to the theory, negative pressure is created due to water evaporation through millions of microscopic capillary pores from tree leaves. The negative pressures are large enough to lift water hundreds of feet against gravity. In an attempt to replicate the process, multiple structures with varying porosity are tested to create negative pressures through water evaporation. The negative pressure created is used to support a water column. The current research is aimed to create artificial leaves using porous structures and be able to transport water in high rise buildings using renewable energy sources such as solar power.

  4. Screening models for releases of radionuclides to atmosphere, surface water, and ground -- Work sheets

    International Nuclear Information System (INIS)

    Three levels of screening for the atmospheric transport pathways and two levels for surface water are presented. The ground has only one screening level. Level 1 is the simplest approach and incorporates a high degree of conservatism. The estimate of the effective dose for this level assumes a concentration based upon the radionuclide concentration at the point of emission to the environment, i.e., at the stack for atmospheric emissions, at the end of the effluent pipe for liquid effluent releases, and at a well because of the buried radioactive material. Levels 2 and 3 are presented for atmospheric releases, and Level 2 for surface water releases only and are more detailed and correspondingly less conservative. Level 2 screening accounts for dispersion in the atmosphere and in surface waters and combines all recognized pathways into the screening factor. For the atmospheric pathway, Level 3 screening includes more definitive pathways analysis. Should the user be found in compliance on the basis of Level 1 screening, no further calculations are required. If the user fails Level 1, the user proceeds to the next level and checks for compliance. This process is repeated until the user passes screening (is in compliance) or no further screening levels exist. If the user fails the final level, professional assistance should be obtained in environmental radiological assessment. Work sheets are designed to lead the user through screening in a step-by-step manner until compliance is demonstrated or it is determined that more sophisticated methods or expertise are needed. Flow diagrams are provided as a guide to identify key steps in the screening process

  5. Temperature influence on water transport in hardened cement pastes

    International Nuclear Information System (INIS)

    Describing water transport in concrete is an important issue for the durability assessment of radioactive waste management reinforced concrete structures. Due to the waste thermal output such structures would be submitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature on water transport within hardened cement pastes of four different formulations. Using a simplified approach (describing only the permeation of liquid water) we characterized the properties needed to describe water transport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presented and discussed

  6. Temperature influence on water transport in hardened cement pastes

    Energy Technology Data Exchange (ETDEWEB)

    Drouet, Emeline [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Poyet, Stéphane, E-mail: stephane.poyet@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Torrenti, Jean-Michel [Université Paris-Est, IFSTTAR, Département Matériaux & Structures, 14-52 boulevard Newton, F-77447 Marne la Vallée cedex 2 (France)

    2015-10-15

    Describing water transport in concrete is an important issue for the durability assessment of radioactive waste management reinforced concrete structures. Due to the waste thermal output such structures would be submitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature on water transport within hardened cement pastes of four different formulations. Using a simplified approach (describing only the permeation of liquid water) we characterized the properties needed to describe water transport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presented and discussed.

  7. The Economics of Bulk Water Transport in Southern California

    Directory of Open Access Journals (Sweden)

    Andrew Hodges

    2014-12-01

    Full Text Available Municipalities often face increasing demand for limited water supplies with few available alternative sources. Under some circumstances, bulk water transport may offer a viable alternative. This case study documents a hypothetical transfer between a water utility district in northern California and urban communities located on the coast of central and southern California. We compare bulk water transport costs to those of constructing a new desalination facility, which is the current plan of many communities for increasing supplies. We find that using water bags to transport fresh water between northern and southern California is in some instances a low-cost alternative to desalination. The choice is constrained, however, by concerns about reliability and, thus, risk. Case-study results demonstrate the challenges of water supply augmentation in water-constrained regions.

  8. Turbulent Transport Mechanics at the Forest-Atmosphere Interface

    Science.gov (United States)

    Katul, Gabriel

    1999-11-01

    A new method is developed to estimate momentum and scalar sources and sinks from measured mean concentration profiles within forested canopies (termed as the "Inverse" problem). The method combines many of the practical advantages of a previously proposed Lagrangian Localized Near Field theory and higher order Eulerian closure principles. Particularly, this "hybrid" method successfully combines the essential physics of closure modeling and the robustness of the regression source inversion developed for the Localized Near Field theory. The method is tested using measured mean CO2 concentration and eddy-covariance fluxes collected in a 15 year-old pine forest for a wide range of atmospheric stability conditions and using temperature and sensible heat flux measurements collected in a wind tunnel for a planar heat source. It is demonstrated that the newly proposed method is well suited for routine source and flux distribution inferences within the canopy.

  9. Controlled Microdroplet Transport in an Atmospheric Pressure Microplasma

    CERN Document Server

    Maguire, P D; Kelsey, C P; Bingham, A; Montgomery, E P; Bennet, E D; Potts, H E; Rutherford, D; McDowell, D A; Diver, D A; Mariotti, D

    2015-01-01

    We report the controlled injection of near-isolated micron-sized liquid droplets into a low temperature He-Ne steady-state rf plasma at atmospheric pressure. The H2O droplet stream is constrained within a 2 mm diameter quartz tube. Imaging at the tube exit indicates a log-normal droplet size distribution with an initial count mean diameter of 15 micrometers falling to 13 micrometers with plasma exposure. The radial velocity profile is approximately parabolic indicating near laminar flow conditions with the majority of droplets travelling at >75% of the local gas speed and having a plasma transit time of < 100 microseconds. The maximum gas temperature, determined from nitrogen spectral lines, was below 400 K and the observed droplet size reduction implies additional factors beyond standard evaporation, including charge and surface chemistry effects. The successful demonstration of controlled microdroplet streams opens up possibilities for gas-phase microreactors and remote delivery of active species for pla...

  10. RETADDII: modeling long-range atmospheric transport of radionuclides

    International Nuclear Information System (INIS)

    A versatile model is described which estimates atmospheric dispersion based on plume trajectories calculated for the mixed layer. This model allows the treatment of the dispersal from a source at an arbitrary height while taking account of plume depletion by dry and wet deposition together with the decay of material to successor species. The plume depletion, decay and growth equations are solved in an efficient manner which can accommodate up to eight pollutants (i.e. a parent and seven serial decay products). The code is particularly suitable for applications involving radioactive chain decay or for cases involving chemical species with successor decay products. Arbitrary emission rates can be specified for the members of the chain or, as is commonly the case, a sole emission rate can be specified for the first member. The code, in its current configuration, uses readily available upper-air wind data for the North American continent

  11. Habitability of waterworlds: runaway greenhouses, atmospheric expansion, and multiple climate states of pure water atmospheres.

    Science.gov (United States)

    Goldblatt, Colin

    2015-05-01

    There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds." I map these as a function of solar constant for planets ranging in size from Mars-sized to 10 Earth-mass. The states are as follows: globally ice covered (Ts ⪅ 245 K), cold and damp (270 ⪅ Ts ⪅ 290 K), hot and moist (350 ⪅ Ts ⪅ 550 K), and very hot and dry (Tsx2A86;900 K). No stable climate exists for 290 ⪅ T s ⪅ 350 K or 550 ⪅ Ts ⪅ 900 K. The union of hot moist and cold damp climates describes the liquid water habitable zone, the width and location of which depends on planet mass. At each solar constant, two or three different climate states are stable. This is a consequence of strong nonlinearities in both thermal emission and the net absorption of sunlight. Across the range of planet sizes, I account for the atmospheres expanding to high altitudes as they warm. The emitting and absorbing surfaces (optical depth of unity) move to high altitude, making their area larger than the planet surface, so more thermal radiation is emitted and more sunlight absorbed (the former dominates). The atmospheres of small planets expand more due to weaker gravity; the effective runaway greenhouse threshold is about 35 W m(-2) higher for Mars, 10 W m(-2) higher for Earth or Venus, but only a few W m(-2) higher for a 10 Earth-mass planet. There is an underlying (expansion-neglected) trend of increasing runaway greenhouse threshold with planetary size (40 W m(-2) higher for a 10 Earth-mass planet than for Mars). Summing these opposing trends means that Venus-sized (or slightly smaller) planets are most susceptible to a runaway greenhouse. The habitable zone for pure water atmospheres is very narrow, with an insolation range of 0.07 times the solar constant. A wider habitable zone requires background gas and greenhouse gas: N2 and CO2 on Earth, which are biologically controlled. Thus, habitability depends on inhabitance. PMID:25984919

  12. Habitability of waterworlds: runaway greenhouses, atmospheric expansion and multiple climate states of pure water atmospheres

    CERN Document Server

    Goldblatt, Colin

    2015-01-01

    There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds". I map these as a function of solar constant for planets ranging in size from Mars size to 10 Earth-mass. The states are: globally ice covered (Ts< 245K), cold and damp (270 < Ts< 290K), hot and moist (350< Ts< 550K) and very hot and dry (Ts< 900K). No stable climate exists for 290< Ts < 350K or 550 < Ts < 900K. The union of hot moist and cold damp climates describe the liquid water habitable zone, the width and location of which depends on planet mass. At each solar constant, two or three different climate states are stable. This is a consequence of strong non-linearities in both thermal emission and the net absorption of sunlight. Across the range of planet sizes, I account for the atmospheres expanding to high altitudes as they warm. The emitting and absorbing surfaces (optical depth of unity) move to high altitude, making their area larger than the planet surfa...

  13. Atmospheric Fate and Transport of Agricultural Dust and Ammonia

    Science.gov (United States)

    Hiranuma, N.; Brooks, S. D.; Thornton, D. C.; Auvermann, B. W.; Fitz, D. R.

    2008-12-01

    Agricultural fugitive dust and odor are significant sources of localized air pollution in the semi-arid southern Great Plains. Daily episodes of ground-level fugitive dust emissions from the cattle feedlots associated with increased cattle activity in the early evenings are routinely observed, while consistently high ammonia is observed throughout the day. Here we present measurements of aerosol size distributions and concentrations of gas and particulate phase ammonia species collected at a feedlot in Texas during summers of 2006, 2007 and 2008. A GRIMM sequential mobility particle sizer and GRIMM 1.108 aerosol spectrometer were used to determine aerosol size distributions in the range of 10 nm to 20 µm aerodynamic diameter at the downwind and upwind edges of the facility. Using aqueous scrubbers, simultaneous measurements of both gas phase and total ammonia species present in the gas and particle phases were also collected. In addition to the continuous measurements at the edges of the facility, coincident aerosol and ammonia measurements were obtain at an additional site further downwind (~3.5 km). Taken together our measurements will be used to quantify aerosol and ammonia dispersion and transport. Relationships between the fate and transport of the aerosols and ammonia will be discussed.

  14. Water vapor and gas transport through polymeric membranes

    OpenAIRE

    Metz, S. J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air). Depending on the application a high or low permeability or selectivity is preferable. This thesis investigates the transport of water vapor and various gases through polyethylene oxide (PEO) polybutyl...

  15. A-TOUGH: A multimedia fluid-flow/energy-transport model for fully-coupled atmospheric-subsurface interactions

    International Nuclear Information System (INIS)

    Modeling the extreme thermodynamic conditions encountered in the near-ground surface atmosphere-soil boundary in desert environments requires a robust code that is capable of simulating fully-coupled flow and transports of water liquid, water vapor, and heat in porous and fractured media - where flow is usually laminar, and the atmosphere - where flow is usually turbulent. A-TOUGh (Atmospheric TOUGH) is developed to simulate the transport of air, vapor, and heat through an atmospheric boundary layer coupled with the transport of moisture, an air-vapor mixture, and heat through porous or fractured media. The three-dimensional nature of the code allows simulation of rough terrain and heterogeneous subsurface conditions encountered at site such as Yucca Mountain. The allowable range of temperatures (-50 degrees C to 200 degrees C) and relative humidities (0 to 100 percent) for this new code permits the simulation of complex processes such as condensation in fractures during the winter season. A-TOUGH can also be used to predict the effect that ventilation shafts and tunnels in underground facilities have on moisture conditions in the host fractured rocks over extended periods of time. A-TOUGH has been tested with several simple and complicated problem sets, including a two-dimensional low-level radioactive waste trench with a layered cap. This paper: (1) summarizes the physical and mathematical approach used by previous investigators and the current study to simulate near-surface unsaturated flow processes, (2) briefly describes the numerical procedures incorporated in A-TOUGH, and (3) presents the results of a calibration simulation based on published field data

  16. He^2+ transport in the Martian upper atmosphere with an induced magnetic field

    OpenAIRE

    Shematovich, Valery; Bisikalo, Dimitri; Stenberg, Gabriella; Barabash, Stas; Dieval, Catherine; Gerard, Jean Claude

    2013-01-01

    Solar wind helium may be a significant source of neutral helium in the Martian atmosphere. The precipitating particles also transfer mass, energy, and momentum. To investigate the transport of He^2+ in the upper atmosphere of Mars, we have applied the direct simulation Monte Carlo method to solve the kinetic equation. We calculate the upward He, He^+, and He^2+ fluxes, resulting from energy spectra of the downgoing He^2+ observed below 500 km altitude by the Analyzer of Space Plasmas and Ener...

  17. Estimating bacteria emissions from inversion of atmospheric transport: sensitivity to modelled particle characteristics

    OpenAIRE

    S. M. Burrows; Rayner, P. J.; Butler, T; M. G. Lawrence

    2013-01-01

    Model-simulated transport of atmospheric trace components can be combined with observed concentrations to obtain estimates of ground-based sources using various inversion techniques. These approaches have been applied in the past primarily to obtain source estimates for long-lived trace gases such as CO2. We consider the application of similar techniques to source estimation for atmospheric aerosols, using as a case study the estimation of bacteria emissio...

  18. Atmospheric Transport of Radioactive Nuclides from Russia to Neighboring Countries

    OpenAIRE

    Romanova, V.; Takano, M

    2002-01-01

    On August 10, 1985, during the completion of reactor fueling network on a nuclear submarine at Chazhma Cove near Vladivostok, an uncontrolled chain reaction occurred. The air, ground and water were radioactively contaminated. The Vladivostok region (southern Primoriye Kray) still contains several nuclear fleet facilities where periodic refueling of submarines is carried out. In addition, there are about 60 decommissioned submarines that have been waiting for many years for final defueling. Th...

  19. Atmospheric CO2 Enrichment of Water Hyacinths: Effects on Transpiration and Water Use Efficiency

    Science.gov (United States)

    Idso, Sherwood B.; Kimball, Bruce A.; Anderson, Michael G.

    1985-11-01

    Open-top clear plastic wall chambers enclosing pairs of sunken metal stock tanks, one of each pair of which contained a full cover of water hyacinths, were maintained out-of-doors at Phoenix, Arizona for several weeks during the summer of 1984. One of these chambers represented ambient conditions, while the other three were continuously enriched with carbon dioxide to approximate target concentrations of 500, 650, and 900 ppm. During a 4-week period when plant growth was at its maximum, water hyacinth biomass production increased by 36% for a 300-600 ppm doubling of the atmospheric CO2 content, while water use efficiency, or the biomass produced per unit of water transpired, actually doubled. These results are similar to what has been observed in several terrestrial plants and they indicate the general trend which may be expected to occur as atmospheric CO2 continues to rise in the years ahead.

  20. The long-range transport of atmospheric aerosols from South Asia to Himalayas

    Science.gov (United States)

    Cong, Zhiyuan; Kang, Shichang; Kawamura, Kimitaka

    2016-04-01

    High levels of carbonaceous aerosol exist over South Asia, the area adjacent to the Himalayas and Tibetan Plateau. Little is known about if they can be transported across the Himalayas, and as far inland as the Tibetan Plateau. To resolve such scientific questions, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research(QOMS, 4276 m a.s.l.). In the laboratory, major ions, elemental carbon, organic carbon, levoglucosan, water-soluble organic carbon, and organic acids were analyzed. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate. The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH+4 , K+, NO‑ and SO2‑) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol compo-sition reported previously from the southern slope of the Himalayas. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. Molecular distributions of dicarboxylic acids and related compounds (malonic acid/ succinic acid, maleic acid/fumaric acid) further support this finding. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. In addition to large-scale atmospheric circulation, the unique mountain/valley breeze system can also have an important effect on air-pollutant transport.With the consideration of the darkening force of

  1. Impact of Atmospheric Long Range Transport of Lead, Mercury and Cadmium on the Swedish Forest Environment

    International Nuclear Information System (INIS)

    Emissions of Hg, Pb, and Cd to air are transported over wide areas in Europe and deposited far away from their sources. About 80% of the atmospheric deposition of these metals in south Sweden originate from emissions in other countries. As a result of the increased anthropogenic deposition the concentrations of Hg, Pb, and Cd in the morlayer of forest soils have increased considerably, mainly during the 20th century. Although the atmospheric deposition of these elements has declined during the most recent decades, the reduction of the input of Hg and Pb is not sufficient to prevent a further accumulation. The concentrations of Hg and Pb are still increasing by ca. 0.5and ca. 0.2% annually in the surface layer of forest soils.In contrast, the Cd concentration is currently decreasing in a large part of Sweden as a result of both deposition decreases and enhanced leaching induced by soil acidification. The accumulation factors of Hg and Pb, especially in the forest topsoils of south Sweden, are already above those at which adverse effects on soil biological processes and organisms have been demonstrated in studies of gradients from local emission sources and laboratory assessment. There are also indications of such effects at the current regional concentrations of Hg and Pbin mor layers from south Sweden, judging from observations in field and laboratory studies. There is an apparent risk of Pb induced reduction in microbial activity over parts of south Sweden. This might cause increased accumulation of organic matter and a reduced availability of soil nutrients. At current concentrations of Hg in Swedish forest soils,effects similar to those of Pb are likely. Increased concentrations of these elements in organs of mammals and birds have also been measured, though decreases have been demonstrated in recent years, related to changes in atmospheric deposition rates. As a result of current and past deposition in south Sweden, concentrations of Hg in fish have increased

  2. Atmospheric forcing of the upper ocean transport in the Gulf of Mexico: From seasonal to diurnal scales

    Science.gov (United States)

    Judt, Falko; Chen, Shuyi S.; Curcic, Milan

    2016-06-01

    The 2010 Deepwater Horizon oil spill in the Gulf of Mexico (GoM) was an environmental disaster, which highlighted the urgent need to predict the transport and dispersion of hydrocarbon. Although the variability of the atmospheric forcing plays a major role in the upper ocean circulation and transport of the pollutants, the air-sea interaction on various time scales is not well understood. This study provides a comprehensive overview of the atmospheric forcing and upper ocean response in the GoM from seasonal to diurnal time scales, using climatologies derived from long-term observations, in situ observations from two field campaigns, and a coupled model. The atmospheric forcing in the GoM is characterized by striking seasonality. In the summer, the time-average large-scale forcing is weak, despite occasional extreme winds associated with hurricanes. In the winter, the atmospheric forcing is much stronger, and dominated by synoptic variability on time scales of 3-7 days associated with winter storms and cold air outbreaks. The diurnal cycle is more pronounced during the summer, when sea breeze circulations affect the coastal regions and nighttime wind maxima occur over the offshore waters. Realtime predictions from a high-resolution atmosphere-wave-ocean coupled model were evaluated for both summer and winter conditions during the Grand LAgrangian Deployment (GLAD) in July-August 2012 and the Surfzone Coastal Oil Pathways Experiment (SCOPE) in November-December 2013. The model generally captured the variability of atmospheric forcing on all scales, but suffered from some systematic errors.

  3. Time-dependent atmospheric CO2 inversions based on interannually varying tracer transport

    International Nuclear Information System (INIS)

    The use of inverse calculations to estimate surface CO2 fluxes from atmospheric concentration measurements has gained large attention in recent years. The success of an inversion will, among other factors, depend strongly on how realistically atmospheric tracer transport is represented by the employed transport model, as it links surface CO2 fluxes to modelled concentrations at the location of measurement stations. We present sensitivity studies demonstrating that transport modelling should be based on interannually varying meteorology, as compared to the traditional use of repeating a single year's winds only. Moreover, we propose an improved procedure of representing the concentration sampling in the model, which allows consistency with the measurements and uses their information content more efficiently. In further sensitivity tests, we estimate the effect of different spatial transport model resolutions and different meteorological driver data sets. Finally, we assess the quality of the inversion results with the help of independent measurements and flux estimates, and preliminarily discuss some of the resulting features

  4. Proton and hydrogen atoms transport in the Martian upper atmosphere with an induced magnetic field

    OpenAIRE

    Shematovich, Valery; Bisikalo, Dimitri; Dieval, Catherine; Barabash, Stas; Stenberg, Gabriella; Nilsson, Hans; Futaana, Yoshifumi; Holmstrom, Mats; Gerard, Jean Claude

    2011-01-01

    We have applied the Direct Simulation Monte Carlo method to solve the kinetic equation for the H/H^+ transport in the upper Martian atmosphere. We calculate the upward H and H^+ fluxes, values that can be measured, and the altitude profile of the energy deposition to be used to understand the energy balance in the Martian atmosphere. The calculations of the upward flux have been made for the Martian atmosphere during solar minimum. We use an energy spectrum of the down moving protons in the a...

  5. Springtime trans-pacific atmospheric transport from east Asia: a transit-time-pdf approach

    Science.gov (United States)

    Holzer, M.; McKendry, I.; Jaffe, D.

    2003-04-01

    The atmosphere is known to episodically transport aerosols, dust, and gaseous pollutants from industrialized south-east Asia, the Gobi desert, and Siberian wild fires to western North America. We give a novel characterization of the ever-present background transport from these regions and of the probability of transport ``events", that is, long-range transport of high concentrations with minimal dispersion. Our primary transport diagnostic is the transit-time probability density function (pdf), {\\cal G}, which is a tracer-independent measure of the flow that allows us to isolate the role of transport from other factors such as source variability and chemistry. The pdf approach, unlike typical back-trajectory analyses, captures transport due to all possible paths and accounts for both resolved advection and subgrid processes. We use a numerical model of the global atmosphere (MATCH), driven by NCEP reananlysis data, to establish the springtime statistics of daily averages of {\\cal G}. A suitably defined average of {\\cal G} quantifies the mass fraction of background air of a given transit time, or age, from the source regions. An analysis of the variability of {\\cal G} at fixed transit time allows us to identify transport events and to estimate their probability of occurrence. This is illustrated for transport events to the ``Pacific-North-West" (PNW) region of North America, defined as (43.8o-53.3o{N}) × (115.3o-124.7o{W}). Correlations between {\\cal G} averaged over the PNW and the winds at any point in the atmosphere identify large-scale anomaly structures of the flow that correspond to favorable transport to the PNW.

  6. Global modelling of the early Martian climate under a denser CO2 atmosphere: Water cycle and ice evolution

    CERN Document Server

    Wordsworth, R; Millour, E; Head, J; Madeleine, J -B; Charnay, B

    2012-01-01

    We discuss 3D global simulations of the early Martian climate that we have performed assuming a faint young Sun and denser CO2 atmosphere. We include a self-consistent representation of the water cycle, with atmosphere-surface interactions, atmospheric transport, and the radiative effects of CO2 and H2O gas and clouds taken into account. We find that for atmospheric pressures greater than a fraction of a bar, the adiabatic cooling effect causes temperatures in the southern highland valley network regions to fall significantly below the global average. Long-term climate evolution simulations indicate that in these circumstances, water ice is transported to the highlands from low-lying regions for a wide range of orbital obliquities, regardless of the extent of the Tharsis bulge. In addition, an extended water ice cap forms on the southern pole, approximately corresponding to the location of the Noachian/Hesperian era Dorsa Argentea Formation. Even for a multiple-bar CO2 atmosphere, conditions are too cold to a...

  7. Transport behavior of water molecules through two-dimensional nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chongqin; Li, Hui; Meng, Sheng, E-mail: smeng@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-11-14

    Water transport through a two-dimensional nanoporous membrane has attracted increasing attention in recent years thanks to great demands in water purification and desalination applications. However, few studies have been reported on the microscopic mechanisms of water transport through structured nanopores, especially at the atomistic scale. Here we investigate the microstructure of water flow through two-dimensional model graphene membrane containing a variety of nanopores of different size by using molecular dynamics simulations. Our results clearly indicate that the continuum flow transits to discrete molecular flow patterns with decreasing pore sizes. While for pores with a diameter ≥15 Å water flux exhibits a linear dependence on the pore area, a nonlinear relationship between water flux and pore area has been identified for smaller pores. We attribute this deviation from linear behavior to the presence of discrete water flow, which is strongly influenced by the water-membrane interaction and hydrogen bonding between water molecules.

  8. Modeling atmospheric deposition using a stochastic transport model

    International Nuclear Information System (INIS)

    An advanced stochastic transport model has been modified to include the removal mechanisms of dry and wet deposition. Time-dependent wind and turbulence fields are generated with a prognostic mesoscale numerical model and are used to advect and disperse individually released particles that are each assigned a mass. These particles are subjected to mass reduction in two ways depending on their physical location. Particles near the surface experience a decrease in mass using the concept of a dry deposition velocity, while the mass of particles located within areas of precipitation are depleted using a scavenging coefficient. Two levels of complexity are incorporated into the particle model. The simple case assumes constant values of dry deposition velocity and scavenging coefficient, while the more complex case varies the values according to meteorology, surface conditions, release material, and precipitation intensity. Instantaneous and cumulative dry and wet deposition are determined from the mass loss due to these physical mechanisms. A useful means of validating the model results is with data available from a recent accidental release of Cesium-137 from a steel-processing furnace in Algeciras, Spain in May, 1998. This paper describes the deposition modeling technique, as well as a comparison of simulated concentration and deposition with measurements taken for the Algeciras release

  9. The atmospheric transport of iodine-129 from Fukushima to British Columbia, Canada and its deposition and transport into groundwater

    Science.gov (United States)

    Herod, Matt N.; Suchy, Martin; Cornett, R. Jack; Kieser, W. E.; Clark, Ian D.; Graham, Gwyn

    2015-12-01

    The Fukushima-Daiichi nuclear accident (FDNA) released iodine-129 (15.7 million year half-life) and other fission product radionuclides into the environment in the spring and summer of 2011. 129I is recognized as a useful tracer for the short-lived radiohazard 131I, which has a mobile geochemical behavior with potential to contaminate water resources. To trace 129I released by the FDNA reaching Canada, pre-accident and post-accident rain samples collected in Vancouver, on Saturna Island and from the National Atmospheric Deposition Program in Washington State were measured. Groundwater from the Abbotsford-Sumas Aquifer was sampled to determine the fate of 129I that infiltrates below the root zone. Modeling of vadose zone transport was performed to constrain the travel time and retardation of 129I. The mean pre-accident 129I concentration in rain was 31 × 106 atoms/L (n = 4). Immediately following the FDNA, 129I values increased to 211 × 106 atoms/L and quickly returned to near-background levels. However, pulses of elevated 129I continued for several months. The increases in 129I concentrations from both Vancouver and Saturna Island were synchronized, and occurred directly after the initial release from the FDNA. The 129I in shallow (3H/3He age <1.4 years) Wassenaar et al. (2006) groundwater showed measurable variability through March 2013 with an average of 3.2 × 106 atoms/L (n = 32) that was coincident with modeled travel times for Fukushima 129I. The groundwater response and the modeling results suggest that 129I was partially attenuated in soil, which is consistent with its geochemical behavior; however, we conclude that the measured variability may be due to Fukushima 129I entering groundwater.

  10. Atmospheric electrical field measurements near a fresh water reservoir and the formation of the lake breeze

    Directory of Open Access Journals (Sweden)

    Francisco Lopes

    2016-06-01

    Full Text Available In order to access the effect of the lakes in the atmospheric electrical field, measurements have been carried out near a large man-made lake in southern Portugal, the Alqueva reservoir, during the ALqueva hydro-meteorological EXperiment 2014. The purpose of these conjoint experiments was to study the impact of the Alqueva reservoir on the atmosphere, in particular on the local atmospheric electric environment by comparing measurements taken in the proximity of the lake. Two stations 10 km apart were used, as they were located up- and down-wind of the lake (Amieira and Parque Solar, respectively, in reference to the dominant northwestern wind direction. The up-wind station shows lower atmospheric electric potential gradient (PG values than the ones observed in the down-wind station between 12 and 20 UTC. The difference in the atmospheric electric PG between the up-wind and the down-wind station is ~30 V/m during the day. This differential occurs mainly during the development of a lake breeze, between 10 and 18 UTC, as a consequence of the surface temperature gradient between the surrounding land and the lake water. In the analysis presented, a correlation is found between the atmospheric electric PG differences and both wind speed and temperature gradients over the lake, thus supporting the influence of the lake breeze over the observed PG variation in the two stations. Two hypotheses are provided to explain this observation: (1 The air that flows from the lake into the land station is likely to increase the local electric conductivity through the removal of ground dust and the transport of cleaner air from higher altitudes with significant light ion concentrations. With such an increase in conductivity, it is expected to see a reduction of the atmospheric electric PG; (2 the resulting air flow over the land station carries negative ions formed by wave splashing in the lake's water surface, as a result of the so-called balloelectric effect

  11. The slant path atmospheric refraction calibrator - An instrument to measure the microwave propagation delays induced by atmospheric water vapor

    Science.gov (United States)

    Walter, Steven J.; Bender, Peter L.

    1992-01-01

    The water vapor-induced propagation delay experienced by a radio signal traversing the atmosphere is characterized by the Slant Path Atmospheric Refraction Calibrator (SPARC), which measures the difference in the travel times between an optical and a microwave signal propagating along the same atmospheric path with an accuracy of 15 picosec or better. Attention is given to the theoretical and experimental issues involved in measuring the delay induced by water vapor; SPARC measurements conducted along a 13.35-km ground-based path are presented, illustrating the instrument's stability, precision, and accuracy.

  12. Symposium on intermediate-range atmospheric-transport processes and technology assessment. [Lead Abstract

    Energy Technology Data Exchange (ETDEWEB)

    1981-10-01

    Separate abstracts were prepared for the 47 papers in this proceedings. The purpose of this meeting was to assess the state of the art of modeling atmospheric transport processes 10 to 100 km downwind of point and area sources of pollution. (KRM)

  13. Symposium on intermediate-range atmospheric-transport processes and technology assessment

    International Nuclear Information System (INIS)

    Separate abstracts were prepared for the 47 papers in this proceedings. The purpose of this meeting was to assess the state of the art of modeling atmospheric transport processes 10 to 100 km downwind of point and area sources of pollution

  14. On the characteristics of water vapor transport from atmosphere boundary layer to stratosphere over Tibetan Plateau regions in summer%夏季青藏高原地区近地层水汽进入平流层的特征分析

    Institute of Scientific and Technical Information of China (English)

    陈斌; 徐祥德; 杨帅; 卞建春

    2012-01-01

    Identification of the main mechanism of water vapor transportation from atmosphere surface layer into stratosphere over Asian monsoon region, especially for the region of Tibetan Plateau (TP), plays a significant role in understanding the global climate change and globalenvironment. In order to investigate the possible mechanism of water vapor transportation from the surface layer to upper troposphere and stratosphere, we used the Lagrangian particle dispersion model FLEXPART driven by the hourly output generated by the weather research and forecasting (WRF) model for the period from 20 to 26 August, 2006. Based on the three-dimensional trajectories backward tracing analysis and their changes in temperature, humidity and other physical variables, our results show that small-scale convection lift and the large-scale transportation are the two main factors responsible for the water vapor entry from surface layer to stratosphere. Air parcels from the surface layer could be lifted up to 9~12 km height via active convention within 24 hours, and then passed through the tropopause in the Tibetan Plateau southeast, which was driven by the large scale advection associated with the south Asian anticyclone circulation. Most air parcels could further transport to lower latitudes and impact the global troposphere-stratosphere water vapor budget. Air parcels on the cloud top height were largely located over the northwest of TP, whereas their locations of Laglangrian minimum temperature, I. E. , where the air parcels dehydration happened, were mostly located in the south of TP. The potential temperature difference between these two regions is about 15 ~ 35 K, implying a significant dehydration processes for all air parcels. This result indicates that that the mechanism of water vapor transportation from atmosphere surface layer to stratosphere over Tibetan Plateau regions in summer is potentially controlled by large scale circulation associated with southern Asian monsoon, while

  15. On carbon transport and fate in the East Siberian Arctic land–shelf–atmosphere system

    International Nuclear Information System (INIS)

    This review paper summarizes current understanding of the transport of organic carbon to, and the fate of organic carbon within, the East Siberian Arctic Shelf (ESAS), and of processes determining carbon dioxide (CO2) and methane (CH4) fluxes from the ESAS to the atmosphere achieved from analyzing the data sets obtained on 20 expeditions performed from 1999 to 2011. This study of the ESAS was aimed at investigating how redistribution of old carbon from degrading terrestrial and sub-sea permafrost and from coastal erosion contributes to the carbon pool of the ESAS, how changes in the hydrological cycle of the surrounding land and alteration of terrestrial carbon cycles affect the hydrological and biogeochemical parameters of shelf water masses, and which factors control CH4 and CO2 emissions from the ESAS. This report describes selected results achieved by a developing international scientific partnership that has been crucial at every stage of the study and will be even more important in the future. (letter)

  16. Effect of atmospheric environment on the attenuation coefficient of light in water

    OpenAIRE

    LIU, JUAN; Shi, Jiulin; Tang, Yijun; Zhu, Kaixing; Ge, Yuan; Chen, Xuegang; He, Xingdao; Liu, Dahe

    2014-01-01

    The attenuation coefficient of 532 nm light in water under different atmospheric conditions was investigated. Measurements were made over a two-year period at the same location and show that the attenuation coefficient is significantly influenced by the atmospheric environment. It is lowest when the atmospheric pressure is high and temperature is low, and is highest when the atmospheric pressure is low and temperature is high. The maximum attenuation coefficient of pure water in these studies...

  17. Finite-bias electronic transport of molecules in water solution

    OpenAIRE

    Sanvito, Stefano; RUNGGER, IVAN; Chen, Xihua

    2010-01-01

    The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated theoretically by using a combination of empirical-potential molecular-dynamics and first-principles electronic-transport calculations. These are at the level of the nonequilibrium Green?s-function method implemented for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic gating to the molecular junction with a gatin...

  18. Development of an advanced atmospheric/transport model for emergency response purposes

    International Nuclear Information System (INIS)

    Atmospheric transport and diffusion models have been developed for real-time calculations of the location and concentration of toxic or radioactive materials during an accidental release at the Savannah River Site (SRS). These models are based Gaussian distributions and have been incorporated into an automated menu-driven program called the WIND (Weather INformation and Display) system. The WIND system atmospheric models employ certain assumptions that allow the computations of the ground-level concentration of toxic or radioactive materials to be made quickly. Gaussian models, such as PF/PL and 2DPUF, suffer from serious limitations including the inability to represent recirculation of pollutants in complex terrain, the use of one stability class at a given time to represent turbulent mixing over heterogeneous terrain, and the use of a wind field computed at only one height in the atmosphere. These limitations arise because the fundamental conservation relations of the atmosphere have been grossly simplified. Three-dimensional coupled atmospheric-dispersion models are not limited by the over-simplifications of the Gaussian assumption and have been used in the past to predict the transport of pollutants in a variety of atmospheric circulations. The disadvantage of these models is that they require large amounts of computational time; however, technology has progressed enough so that real-time simulations of dispersion may be made. These complex models can be run in an operational mode so that routine forecasts of the wind field and particulate concentration can be made

  19. Evidence for short-range transport of atmospheric mercury to a rural, inland site

    Science.gov (United States)

    Rothenberg, Sarah E.; McKee, Lester; Gilbreath, Alicia; Yee, Donald; Connor, Mike; Fu, Xuewu

    2010-03-01

    Atmospheric mercury (Hg) species, including gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate-bound mercury (Hg p), were monitored near three sites, including a cement plant (monitored in 2007 and 2008), an urban site and a rural site (both monitored in 2005 and 2008). Although the cement plant was a significant source of Hg emissions (for 2008, GEM: 2.20 ± 1.39 ng m -3, RGM: 25.2 ± 52.8 pg m -3, Hg p 80.8 ± 283 pg m -3), average GEM levels and daytime average dry depositional RGM flux were highest at the rural site, when all three sites were monitored sequentially in 2008 (rural site, GEM: 2.37 ± 1.26 ng m -3, daytime RGM flux: 29 ± 40 ng m -2 day -1). Photochemical conversion of GEM was not the primary RGM source, as highest net RGM gains (75.9 pg m -3, 99.0 pg m -3, 149 m -3) occurred within 3.0-5.3 h, while the theoretical time required was 14-23 h. Instead, simultaneous peaks in RGM, Hg p, ozone (O 3), nitrogen oxides, and sulfur dioxide in the late afternoon suggested short-range transport of RGM from the urban center to the rural site. The rural site was located more inland, where the average water vapor mixing ratio was lower compared to the other two sites (in 2008, rural: 5.6 ± 1.4 g kg -1, urban: 9.0 ± 1.1 g kg -1, cement plant: 8.3 ± 2.2 g kg -1). Together, these findings suggested short-range transport of O 3 from an urban area contributed to higher RGM deposition at the rural site, while drier conditions helped sustain elevated RGM levels. Results suggested less urbanized environments may be equally or perhaps more impacted by industrial atmospheric Hg emissions, compared to the urban areas from where Hg emissions originated.

  20. A comparison of Lagrangian precipitation statistics computed with two regional-scale atmospheric transport models

    Energy Technology Data Exchange (ETDEWEB)

    Dittenhoefer, A.C.; Ferullo, A.F.

    1984-01-01

    In an earlier paper the authors pointed out that air mass trajectories computed from winds on an isobaric surface or winds averaged throughout a fixed layer were inappropriate for regional-scale acid deposition studies. This is because isobaric and fixed layer models do not adequately treat vertical motions and wind shears that occur during long range transport associated with precipitation. To improve the vertical resolution of regional-scale transport simulations and to more accurately account for large-scale vertical motions and wind shears during thermodynamically stable atmospheric conditions, they developed the enviroplan dual-mode regional air back-trajector model (EDRAB). In this paper they compute Lagrangian precipitation statistics for an entire year of precipitation events at Whiteface Mountain, New York using EDRAB and the widely used NOAA air resources laboratories atmospheric transport and dispersion model (ARL-ATAD).

  1. Atmospheric bromine flux from the coastal Abu Dhabi sabkhat: A ground-water mass-balance investigation

    Science.gov (United States)

    Wood, W.W.; Sanford, W.E.

    2007-01-01

    A solute mass-balance study of ground water of the 3000 km2 coastal sabkhat (salt flats) of the Emirate of Abu Dhabi, United Arab Emirates, documents an annual bromide loss of approximately 255 metric tons (0.0032 Gmoles), or 85 kg/km2. This value is an order of magnitude greater than previously published direct measurements from the atmosphere over an evaporative environment of a salar in Bolivia. Laboratory evidence, consistent with published reports, suggests that this loss is by vapor transport to the atmosphere. If this bromine flux to the atmosphere is representative of the total earth area of active salt flats then it is a significant, and generally under recognized, input to the global atmospheric bromide flux.

  2. Water transportation across narrow channel of nanometer dimension

    Science.gov (United States)

    Wan, Rongzheng; Fang, Haiping

    2010-06-01

    Since the discovery of the carbon nanotube and aquaporin, the study of the transportation of water across nanochannels has become one of the hot subjects. When the radius of a nanochannel is only about one nanometer or a little larger, water confined in those nanoscale channels usually exhibits dynamics different from those in bulk system, such as the wet-dry transition due to the confinement, concerted hydrogen-bond orientations and flipping, concerted motion of water molecules, and strong interactions with external charges. Those dynamics correlate with the unique behavior of the water transportation across the channels, such as the extra-high permeability, excellent on-off gating behavior with response to the external mechanical and electrical signals and noises, enhancement by structure outside the channel, directional transportation driven by charges close to a channel or electric field. In this article, we review some of the recent progress on the study of the water molecules inside those narrow nanochannels.

  3. Impact of inflow transport approximation on light water reactor analysis

    Science.gov (United States)

    Choi, Sooyoung; Smith, Kord; Lee, Hyun Chul; Lee, Deokjung

    2015-10-01

    The impact of the inflow transport approximation on light water reactor analysis is investigated, and it is verified that the inflow transport approximation significantly improves the accuracy of the transport and transport/diffusion solutions. A methodology for an inflow transport approximation is implemented in order to generate an accurate transport cross section. The inflow transport approximation is compared to the conventional methods, which are the consistent-PN and the outflow transport approximations. The three transport approximations are implemented in the lattice physics code STREAM, and verification is performed for various verification problems in order to investigate their effects and accuracy. From the verification, it is noted that the consistent-PN and the outflow transport approximations cause significant error in calculating the eigenvalue and the power distribution. The inflow transport approximation shows very accurate and precise results for the verification problems. The inflow transport approximation shows significant improvements not only for the high leakage problem but also for practical large core problem analyses.

  4. The coordinated development of China' s inland water transport%The coordinated development of China' s inland water transport

    Institute of Scientific and Technical Information of China (English)

    Deng Aimin; Tian Feng; Haasis H.D; Mao Lang; Cai Jia

    2012-01-01

    The coordinated development is the core of sustainable development and the hot issue of international research. Inland water transport (IWT) is an important part of the water resources exploiting system and comprehensive transport system under socio-economic context of river basin, and also the country' s sustainable development priorities to achieve resource-conserving and environment-friendly strategy. Based on the coordinated development content, the paper combined Germany' s successful development experience, explored the elements and problem of the coordinated development of IWT system of China' s national economic strategy and basin economy, water resourse system, comprehensive transport system, and system itself, and their countermeasures and suggestions, in order to facilitate rapid and coordinated development of China' s inland water transport.

  5. Mercury cycling in stream ecosystems. 1. Water column chemistry and transport

    Science.gov (United States)

    Brigham, M.E.; Wentz, D.A.; Aiken, G.R.; Krabbenhoft, D.P.

    2009-01-01

    We studied total mercury (THg) and methylmercury (MeHg) in eight streams, located in Oregon, Wisconsin, and Florida, that span large ranges in climate, landscape characteristics, atmospheric Hg deposition, and water chemistry. While atmospheric deposition was the source of Hg at each site, basin characteristics appeared to mediate this source by providing controls on methylation and fluvial THg and MeHg transport. Instantaneous concentrations of filtered total mercury (FTHg) and filtered methylmercury (FMeHg) exhibited strong positive correlations with both dissolved organic carbon (DOC) concentrations and streamflow for most streams, whereas mean FTHg and FMeHg concentrations were correlated with wetland density of the basins. For all streams combined, whole water concentrations (sum of filtered and particulate forms) of THg and MeHg correlated strongly with DOC and suspended sediment concentrations in the water column. ?? 2009 American Chemical Society.

  6. Coherent water transport across the South Atlantic

    CERN Document Server

    Wang, Y; Beron-Vera, F J

    2015-01-01

    The role of mesoscale eddies in transporting Agulhas leakage is investigated using a recent technique from nonlinear dynamical systems theory applied on geostrophic currents inferred from the over two-decade-long satellite altimetry record. Eddies are found to acquire material coherence away from the Agulhas retroflection, near the Walvis Ridge in the South Atlantic. Yearly, 1 to 4 coherent material eddies are detected with diameters ranging from 40 to 280 km. A total of 23 eddy cores of about 50 km in diameter and with at least 30% of their contents traceable into the Indian Ocean were found to travel across the subtropical gyre with minor filamentation. No more than 5\\% of such cores pour their contents on the North Brazil Current. While ability of eddies to carry Agulhas leakage northwestward across the South Atlantic is supported by our analysis, this is more restricted than suggested by earlier ring transport assessments.

  7. Biologically inspired water purification through selective transport

    International Nuclear Information System (INIS)

    Biologically inspired systems based on cellular mechanics demonstrate the ability to selectively transport ions across a bilayer membrane. These systems may be observed in nature in plant roots, which remove select nutrients from the surrounding soil against significant concentration gradients. Using biomimetic principles in the design of tailored active materials allows for the development of selective membranes for capturing and filtering targeted ions. Combining this biomimetic transport system with a method for reclaiming the captured ions will allow for increased removal potential. To illustrate this concept, a device for removing nutrients from waterways to aid in reducing eutrophication is outlined and discussed. Presented is a feasibility study of various cellular configurations designed for this purpose, focusing on maximizing nutrient uptake. The results enable a better understanding of the benefits and obstacles when developing these cellularly inspired systems. (paper)

  8. Modeling the global atmospheric transport and deposition of mercury to the Great Lakes

    Directory of Open Access Journals (Sweden)

    Mark D. Cohen

    2016-07-01

    Full Text Available Abstract Mercury contamination in the Great Lakes continues to have important public health and wildlife ecotoxicology impacts, and atmospheric deposition is a significant ongoing loading pathway. The objective of this study was to estimate the amount and source-attribution for atmospheric mercury deposition to each lake, information needed to prioritize amelioration efforts. A new global, Eulerian version of the HYSPLIT-Hg model was used to simulate the 2005 global atmospheric transport and deposition of mercury to the Great Lakes. In addition to the base case, 10 alternative model configurations were used to examine sensitivity to uncertainties in atmospheric mercury chemistry and surface exchange. A novel atmospheric lifetime analysis was used to characterize fate and transport processes within the model. Model-estimated wet deposition and atmospheric concentrations of gaseous elemental mercury (Hg(0 were generally within ∼10% of measurements in the Great Lakes region. The model overestimated non-Hg(0 concentrations by a factor of 2–3, similar to other modeling studies. Potential reasons for this disagreement include model inaccuracies, differences in atmospheric Hg fractions being compared, and the measurements being biased low. Lake Erie, downwind of significant local/regional emissions sources, was estimated by the model to be the most impacted by direct anthropogenic emissions (58% of the base case total deposition, while Lake Superior, with the fewest upwind local/regional sources, was the least impacted (27%. The U.S. was the largest national contributor, followed by China, contributing 25% and 6%, respectively, on average, for the Great Lakes. The contribution of U.S. direct anthropogenic emissions to total mercury deposition varied between 46% for the base case (with a range of 24–51% over all model configurations for Lake Erie and 11% (range 6–13% for Lake Superior. These results illustrate the importance of atmospheric

  9. Germany’s water footprint of transport fuels

    International Nuclear Information System (INIS)

    Highlights: • Water footprint of Germany meeting EU biofuel targets was investigated. • Trade analysis ascertained the source and magnitude of the external water footprint. • Policy implementation increased the water footprint of the transport fuel sector 64%. • This study improves upon a previous one undertaken at the EU level. - Abstract: Germany is required by European Union legislation to achieve a 10% mixture of renewable energy in all road transport fuels by the year 2020. This paper intends to quantify the water use impacts of Germany’s compliance with the transport fuel goal of the EU Renewables Directive. Although the stated purpose of this Directive is to reduce greenhouse gas emissions from the transport sector and address energy security concerns, a more encompassing analysis considering sustainable development paths must include other environmental impacts, including water resource use. The water footprint indicator can contribute to a more intelligent environmental analysis of biofuel targets, although it alone cannot attest to the sustainability of human water use. This research builds upon the results of a similar study that aimed to quantify the freshwater impacts of meeting this EU transport fuel goal across Member States. By looking more closely at the case of Germany, country-specific data can be used in the analysis that lead to different results than those reached in the previous study. Results indicate that achieving a 10% mixture of biofuels in the road transport sector could lead to a 64% increase in the water footprint of the transport fuel sector when compared to a baseline scenario of no policy implementation

  10. Atmospheric transport of persistent organic pollutants (POPs) to Bjørnøya (Bear island).

    Science.gov (United States)

    Kallenborn, Roland; Christensen, Guttorm; Evenset, Anita; Schlabach, Martin; Stohl, Andreas

    2007-10-01

    A first medium term monitoring of atmospheric transport and distribution for persistent organic pollutants (POPs) in Bjørnøya (Bear island) air samples has been performed in the period between week 51/1999 and week 28/2003. A total of 50 single compounds consisting of polychlorinated biphenyls (33 congeners), hexachlorobenzene (HCB), hexachlorocyclohexane isomers (alpha-, beta-, gamma-HCH), alpha-endosulfan, cyclodiene pesticides (chlordanes, nonachlor-isomers, oxy-chlordane, heptachlor and chlordane) as well as dichlorodiphenyltrichloroethane (DDT) derivatives were analysed and quantified. Atmospheric transport of POPs was identified as an important contamination source for the island. PCBs, HCB and HCH isomers were the predominant POP groups, contributing with 70-90% to the overall POP burden quantified in the Bjørnøya air samples. The highest concentration levels for a single compound were found for HCB (25-35 pg m(-3)). However, the sum of 33 PCB congeners was found to be in the same concentration range (annual means between 15 and 30 pg m(-3)). Cyclodiene pesticides, DDT derivatives and alpha-endosulfan were identified as minor contaminants. Several atmospheric long-range transport episodes were identified and characterised. Indications for industrial emissions as well as agricultural sources were found for the respective atmospheric transport episodes. A first simple statistical correlation assessment showed that for long-range transport of pollution, the local meteorological situation is not as important as the air mass properties integrated over the time period of the transport event. The local weather situation, on the other hand, is important when investigating deposition rates and up-take/accumulation properties in the local ecosystem. Based upon chemical data interpretation, valuable information about the influence of primary and secondary sources on the air mass contamination with chlorinated insecticides (e.g., HCHs) was found and discussed. The

  11. Deep update with new water transport cost model

    International Nuclear Information System (INIS)

    DEEP 3.11 is a new version of DEEP which is capable to calculate the water transport cost in any place, with acceptable accuracy. The user needs only to specify water flow or the capacity, pipeline length and elevation of sites against sea level or difference in elevation of the beginning and end of the pipeline routs

  12. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  13. Numerical study of the auroral particle transport in the polar upper atmosphere

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

  14. Atmospheric transport of persistent semi-volatile organic chemicals to the Arctic and cold condensation in the mid-troposphere – Part 1: 2-D modeling in mean atmosphere

    Directory of Open Access Journals (Sweden)

    J. Ma

    2010-08-01

    Full Text Available In the first part of this study for revisiting the cold condensation effect on global distribution of semi-volatile organic chemicals (SVOCs, the atmospheric transport of SVOCs to the Arctic in the mid-troposphere in a mean meridional atmospheric circulation over the Northern Hemisphere was simulated by a two-dimensional (2-D atmospheric transport model. Results show that under the mean meridional atmospheric circulation the long-range atmospheric transport of SVOCs from warm latitudes to the Arctic occurs primarily in the mid-troposphere. Although major sources are in low and mid-latitude soils, the modeled air concentration of SVOCs in the mid-troposphere is of the same order as or higher than that near the surface, demonstrating that the mid-troposphere is an important pathway and reservoir of SVOCs. The cold condensation of the chemicals is also likely to take place in the mid-troposphere over a source region of SVOCs in warm low latitudes through interacting with clouds. We demonstrate that the temperature dependent vapour pressure and atmospheric degradation rate of SVOCs exhibit similarities between lower atmosphere over the Arctic and the mid-troposphere over a tropical region. Frequent occurrence of atmospheric ascending motion and convection over warm latitudes carry the chemicals to a higher altitude where some of these chemicals may partition onto solid or aqueous phase through interaction with atmospheric aerosols, cloud water droplets and ice particles, and become more persistent at lower temperatures. Stronger winds in the mid-troposphere then convey solid and aqueous phase chemicals to the Arctic where they sink by large-scale descending motion and wet deposition. Using calculated water droplet-air partitioning coefficient of several persistent organic semi-volatile chemicals under a mean air temperature profile from the equator to the North Pole we propose that clouds are likely important sorbing media for SVOCs and pathway of

  15. Highways in the sky: scales of atmospheric transport of plant pathogens.

    Science.gov (United States)

    Schmale, David G; Ross, Shane D

    2015-01-01

    Many high-risk plant pathogens are transported over long distances (hundreds of meters to thousands of kilometers) in the atmosphere. The ability to track the movement of these pathogens in the atmosphere is essential for forecasting disease spread and establishing effective quarantine measures. Here, we discuss the scales of atmospheric dispersal of plant pathogens along a transport continuum (pathogen scale, farm scale, regional scale, and continental scale). Growers can use risk information at each of these dispersal scales to assist in making plant disease management decisions, such as the timely application of appropriate pesticides. Regional- and continental-scale atmospheric features known as Lagrangian coherent structures (LCSs) may shuffle plant pathogens along highways in the sky. A promising new method relying on overlapping turbulent back-trajectories of pathogen-laden parcels of air may assist in localizing potential inoculum sources, informing local and/or regional management efforts such as conservation tillage. The emergence of unmanned aircraft systems (UASs, or drones) to sample plant pathogens in the lower atmosphere, coupled with source localization efforts, could aid in mitigating the spread of high-risk plant pathogens. PMID:26047561

  16. Validation of 3-D CFD Model of Tritium Transport in the Atmosphere

    International Nuclear Information System (INIS)

    When solving 3-D problems for the atmospheric impurity transport in the bounded area, it is essential for the atmospheric dynamics to be correctly computed taking into account the actual terrain topography and environments specified by the boundary conditions. Such conditions as turbulence, convection, condensation and moisture evaporation processes, etc. are to be also taken into account as well as the interaction processes among impurities (gases, aerosols), atmosphere and the Earth's surface.3-D computational fluid dynamics model(CFD) developed on the basis of SRP hydrodynamic code was used to simulate tritium plume evolution and tritium transport in atmosphere under the area with relatively complex topography. SRP code is based on the continuum motion equations (Navier-Stockes equations) and thermodynamic relations taking into account specific features of atmospheric flows and complex topography and is designed to use on PC-type computers.The model has been validated using experimental release of tritium with specified source term and meteorology. Due to low release height above the underlying surface a fine grid was used in the vertical direction near the underlying surface. HT and HTO/H2O vertical fluxes were taken into account. Evolution of HT and HTO activities at 2 sampling locations along the plume axe were available for model-experiment inter-comparison. The modeling results of HT and HTO activities in the air during plume travel are in satisfactory agreement with observed values

  17. Cluster Analysis of Atmospheric Dynamics and Pollution Transport in a Coastal Area

    Science.gov (United States)

    Sokolov, Anton; Dmitriev, Egor; Maksimovich, Elena; Delbarre, Hervé; Augustin, Patrick; Gengembre, Cyril; Fourmentin, Marc; Locoge, Nadine

    2016-06-01

    Summertime atmospheric dynamics in the coastal zone of the industrialized Dunkerque agglomeration in northern France was characterized by a cluster analysis of back trajectories in the context of pollution transport. The MESO-NH atmospheric model was used to simulate the local dynamics at multiple scales with horizontal resolution down to 500 m, and for the online calculation of the Lagrangian backward trajectories with 30-min temporal resolution. Airmass transport was performed along six principal pathways obtained by the weighted k-means clustering technique. Four of these centroids corresponded to a range of wind speeds over the English Channel: two for wind directions from the north-east and two from the south-west. Another pathway corresponded to a south-westerly continental transport. The backward trajectories of the largest and most dispersed sixth cluster contained low wind speeds, including sea-breeze circulations. Based on analyses of meteorological data and pollution measurements, the principal atmospheric pathways were related to local air-contamination events. Continuous air quality and meteorological data were collected during the Benzene-Toluene-Ethylbenzene-Xylene 2006 campaign. The sites of the pollution measurements served as the endpoints for the backward trajectories. Pollutant transport pathways corresponding to the highest air contamination were defined.

  18. Regional terrestrial water storage change and evapotranspiration from terrestrial and atmospheric water balance computations

    OpenAIRE

    Yeh, Pat J.-F.; J. S. Famiglietti

    2008-01-01

    In this study we estimate the regional terrestrial water storage change (TWSC) and evapotranspiration (ET) in Illinois (∼2 × 105 km2) from reanalysis data for a 22-year period (1984–2005) using terrestrial and atmospheric water balance computations. The estimates are compared with in situ observations of TWSC as well as ET, derived as the residual of observed precipitation, streamflow, and TWSC. The 22-year mean annual cycles of estimated TWSC and ET agree well with observations. Monthly esti...

  19. Transport and scavenging of Pu in surface waters of the Southern Hemisphere Oceans

    DEFF Research Database (Denmark)

    Gastaud, J.; Povinec, P.P.; Aoyama, M.;

    2011-01-01

    The distribution of 239Pu in Atlantic and Indian Ocean waters about four decades after their main injection from atmospheric nuclear weapons tests is discussed. Recent data obtained in the framework of the SHOTS (Southern Hemisphere Ocean Tracer Studies) projects are evaluated and compared with...... previous investigations. Seawater samples were collected during the round the globe BEAGLE2003 (Blue Ocean Global Expedition) along the 30°S transect in the Atlantic and the 20°S transect in the Indian Ocean. The results indicate transport of surface waters labelled with 239Pu from the western North...

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

    Directory of Open Access Journals (Sweden)

    M. Righi

    2015-01-01

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

  1. The model study of water mass and energy exchange between the inland water body and atmosphere

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on a one-dimensional eddy diffusion model,a model to study the water mass and energy exchange between the water body(such as lake and wetland) and the atmosphere is developed,which takes the phase change process due to the seasonal melting and freezing of water and the convection mixing process of energy caused by temperature stratification into consideration. The model uses enthalpy instead of temperature as predictive variable,which will help to deal with the phase change process and to design an efficient numerical scheme for obtaining the solution more easily. The performance of the model and the rationality of taking convection mixing into the consideration are validated by using observed data of Kinneret Lake in Israel and Lower Two Medicine Lake in Montana State in America. The comparison of model results with observed data indicates that the model presented here is capable of describing the physical process of water mass and energy between the water body(lake and wetland) and atmosphere. Comparison of the result from wetland with shallow and deep lakes under the same forcing conditions shows that the evaporation from wetland is much greater than that from lakes,which accords with the real observation fact and physical mechanism.

  2. Kinetics of proton transport in water

    DEFF Research Database (Denmark)

    Kornyshev, A.A.; Kuznetsov, A.M.; Spohr, E.;

    2003-01-01

    The excess proton mobility in water has attracted scientific attention for more than a century. Detailed theoretical concepts and models are also presently in strong focus in efforts toward understanding this ubiquitous phenomenon. In the present report, we discuss a theoretical framework for rat...

  3. Heat Transport Compensation in Atmosphere and Ocean over the Past 22,000 Years

    OpenAIRE

    Haijun Yang; Yingying Zhao; Zhengyu Liu; Qing Li; Feng He; Qiong Zhang

    2015-01-01

    The Earth’s climate has experienced dramatic changes over the past 22,000 years; however, the total meridional heat transport (MHT) of the climate system remains stable. A 22,000-year-long simulation using an ocean-atmosphere coupled model shows that the changes in atmosphere and ocean MHT are significant but tend to be out of phase in most regions, mitigating the total MHT change, which helps to maintain the stability of the Earth’s overall climate. A simple conceptual model is used to under...

  4. Evaluating the costs of desalination and water transport

    OpenAIRE

    Zhou, Y; Tol, R.S.J.

    2005-01-01

    Many regions of the world are facing formidable freshwater scarcity. Although there is substantial scope for economizing on the consumption of water without affecting its service level, the main response to water scarcity has been to increase the supply. To a large extent, this is done by transporting water from places where it is abundant to places where it is scarce. At a smaller scale, and without a lot of public and political attention, people have started to tap into the sheer limitless ...

  5. International Space Station Atmosphere Control and Supply, Atmosphere Revitalization, and Water Recovery and Management Subsystem - Verification for Node 1

    Science.gov (United States)

    Williams, David E.

    2007-01-01

    The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 ACS, AR, and WRM design and detailed Element Verification methodologies utilized during the Qualification phase for Node 1.

  6. Carbon Dioxide in Exoplanetary Atmospheres: Rarely Dominant Compared to Carbon Monoxide and Water in Hot, Hydrogen-dominated Atmospheres

    OpenAIRE

    Heng, Kevin; Lyons, James R.

    2015-01-01

    We present a comprehensive study of the abundance of carbon dioxide in exoplanetary atmospheres in hot, hydrogen-dominated atmospheres. We construct novel analytical models of systems in chemical equilibrium that include carbon monoxide, carbon dioxide, water, methane and acetylene and relate the equilibrium constants of the chemical reactions to temperature and pressure via the tabulated Gibbs free energies. We prove that such chemical systems may be described by a quintic equation for the m...

  7. Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

    Directory of Open Access Journals (Sweden)

    J. P. McCormack

    2008-12-01

    Full Text Available This paper describes CHEM2D-H2O, a new parameterization of H2O photochemical production and loss based on the CHEM2D photochemical-transport model of the middle atmosphere. This parameterization accounts for the altitude, latitude, and seasonal variations in the photochemical sources and sinks of water vapor over the pressure region from 100–0.001 hPa (~16–90 km altitude. A series of free-running NOGAPS-ALPHA forecast model simulations offers a preliminary assessment of CHEM2D-H2O performance over the June 2007 period. Results indicate that the CHEM2D-H2O parameterization improves global 10-day forecasts of upper mesospheric water vapor compared to forecasts using an existing one-dimensional (altitude only parameterization. Most of the improvement is seen at high winter latitudes where the one-dimensional parameterization specifies photolytic H2O loss year round despite the lack of sunlight in winter. The new CHEM2D-H2O parameterization should provide a better representation of the downwelling of dry mesospheric air into the stratospheric polar vortex in operational analyses that do not assimilate middle atmospheric H2O measurements.

  8. Parameterization of middle atmospheric water vapor photochemistry for high-altitude NWP and data assimilation

    Directory of Open Access Journals (Sweden)

    J. P. McCormack

    2008-07-01

    Full Text Available This report describes CHEM2D-H2O, a new parameterization of H2O photochemical production and loss based on the CHEM2D photochemical-transport model of the middle atmosphere. This parameterization accounts for the altitude, latitude, and seasonal variations in the photochemical sources and sinks of water vapor over the pressure region from 100–0.001 hPa (~16–90 km altitude. A series of free-running NOGAPS-ALPHA forecast model simulations offers a preliminary assessment of CHEM2D-H2O performance over the June 2007 period. Results indicate that the CHEM2D-H2O parameterization improves global 10-day forecasts of upper mesospheric water vapor compared to forecasts using an existing one-dimensional (altitude only parameterization. Most of the improvement is seen at high winter latitudes where the one-dimensional parameterization specifies photolytic H2O loss year round despite the lack of sunlight in winter. The new CHEM2D-H2O parameterization should provide a better representation of the downwelling of dry mesospheric air into the stratospheric polar vortex in operational analyses that do not assimilate middle atmospheric H2O measurements.

  9. Isotopic signature of atmospheric xenon released from light water reactors

    International Nuclear Information System (INIS)

    A global monitoring system for atmospheric xenon radioactivity is being established as part of the International Monitoring System to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The isotopic activity ratios of 135Xe, 133mXe, 133Xe and 131mXe are of interest for distinguishing nuclear explosion sources from civilian releases. Simulations of light water reactor (LWR) fuel burn-up through three operational reactor power cycles are conducted to explore the possible xenon isotopic signature of nuclear reactor releases under different operational conditions. It is studied how ratio changes are related to various parameters including the neutron flux, uranium enrichment and fuel burn-up. Further, the impact of diffusion and mixing on the isotopic activity ratio variability are explored. The simulations are validated with reported reactor emissions. In addition, activity ratios are calculated for xenon isotopes released from nuclear explosions and these are compared to the reactor ratios in order to determine whether the discrimination of explosion releases from reactor effluents is possible based on isotopic activity ratios

  10. Impact of Interfacial Water Transport in PEMFCs on Cell Performance

    International Nuclear Information System (INIS)

    Coupled cell performance evaluation, liquid water visualization by neutron radiography (NRG) and numerical modeling based on multiphase mixture (M2) model were performed with three types of GDMs: Micro Porous Layer (MPL) free; Carbon Paper (CP) with MPL; and CP free to investigate interfacial liquid water transport phenomena in PEMFCs and its effect on cell performance. The visualized results of MPL free GDM with different wettability of bi-polar plates (BPPs) showed hydrophilic BPP improved liquid water transport at the interface between CP and channel. Numerical modeling results indicated that this difference with BPP wettability was caused by the liquid water coverage difference on CP surface. Thus, controlling liquid water coverage is the one of the key strategies for improving cell performance. Additionally, liquid water distributions across the cell for three types of GDMs were compared and significant difference in liquid water content at the interface between Catalyst Layer (CL) and GDM was observed. Numerical modeling suggests this difference is influenced by the gap at the interface and that the MPL could minimize this effect. The CP free cell (i.e. only MPL) showed the best performance and the lowest liquid water content. There were multiple impacts of interfacial liquid water transport both at CL-GDM and GDM-channel interfaces. High hydrophobicity and fine structure of MPLs contributed to enhanced liquid water transport at GDM-channel interface and as a result reduced the liquid water coverage. At the same time, MPL improves contact at the CL-GDM interface in the same manner as seen in CP with MPL case. Thus, the CP free concept showed the best performance. It is suggested that the design of the interface between each component of the PEMFC has a great impact on cell performance and plays a significant role in achievement of high current density operation and cost reduction in FCEVs

  11. Momentum and scalar transport within a vegetation canopy following atmospheric stability and seasonal canopy changes: the CHATS experiment

    Directory of Open Access Journals (Sweden)

    S. Dupont

    2012-02-01

    Full Text Available Momentum and scalar (heat and water vapor transfer between a walnut canopy and the overlying atmosphere are investigated for two seasonal periods (before and after leaf-out, and for five thermal stability regimes (free and forced convection, near-neutral condition, transition to stable, and stable. Quadrant and octant analyses of momentum and scalar fluxes followed by space-time autocorrelations of observations from the Canopy Horizontal Array Turbulence Study's (CHATS thirty meter tower help characterize the motions exchanging momentum, heat, and moisture between the canopy layers and aloft.

    During sufficiently windy conditions, i.e. in forced convection, near-neutral and transition to stable regimes, momentum and scalars are generally transported by sweep and ejection motions associated with the well-known canopy-top "shear-driven" coherent eddy structures. During extreme stability conditions (both unstable and stable, the role of these "shear-driven" structures in transporting scalars decreases, inducing notable dissimilarity between momentum and scalar transport.

    In unstable conditions, "shear-driven" coherent structures are progressively replaced by "buoyantly-driven" structures, known as thermal plumes; which appear very efficient at transporting scalars, especially upward thermal plumes above the canopy. Within the canopy, downward thermal plumes become more efficient at transporting scalars than upward thermal plumes if scalar sources are located in the upper canopy as the heat source. We explain these features by suggesting that: (i downward plumes within the canopy correspond to large downward plumes coming from above, and (ii upward plumes within the canopy are local small plumes induced by canopy heat sources where passive scalars are first injected if there sources are at the same location than heat sources. Above the canopy, these small upward thermal plumes aggregate to form larger scale upward thermal plumes

  12. Influence of model resolution on the atmospheric transport of 10Be

    OpenAIRE

    Smith, A M; Heikkilä, U.

    2012-01-01

    Understanding the transport path of the solar activity proxy 10Be from source to archive is crucial for the interpretation of its observed variability. The extent of mixing of the strong production signal has been quantified in a previous study (Heikkilä et al., 2009). In this study we perform sensitivity studies to investigate the influence of model resolution on the level of mixing and transport path of 10Be in the atmosphere using the ECHAM5-HAM aerosol-climate model. This study per...

  13. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    OpenAIRE

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Gabriel J Bowen

    2015-01-01

    Human activities affect the water cycle in many ways, some of which remain difficult to measure. One such process is emission of water vapor through combustion of fossil fuels, which may be a significant part of the atmospheric water budget in urban centers. It has not previously been possible to uniquely identify combustion-derived water vapor with atmospheric measurements. We introduce a method for the measurement of combustion-derived vapor, and show that this source contributes as much as...

  14. The efficiency and sensitivity analysis of observations for atmospheric transport model with emissions

    Science.gov (United States)

    Wu, Xueran; Elbern, Hendrik; Jacob, Birgit

    2015-04-01

    Air quality and climate change are influenced by the fluxes of green house gases, reactive emissions and aerosols in the atmosphere. But observations of the chemical states in the atmosphere typically have low temporal and spatial density. Therefore, many works are introduced to spatio-temporal data assimilation methods in atmospheric chemistry in recent years. There is no doubt that the optimization of the initial state is always of great importance for the improvement of predictive skill. However, specified to the chemistry transport model with high dependence on the emissions in the troposphere, the optimization of the initial state is no longer the only issue. The lack of the ability to observe and estimate surface emission fluxes and important inner atmospheric fluxes with necessary accuracy is a major roadblock of hampering the progress in predictive skills of the atmospheric transport model. However, in many cases, the better estimations for both the initial state and emission rates are not always obtained with certain observational network configurations via various popular data assimilation methods, such as the ensemble Kalman filter and smoother and 4D-variation. It leads to the waste of resource by optimizing the improper parameters or brings the inaccuracy of the optimization by unsuitable weight between the initial state and emission rates. Hence, in order to make a scientific and quantitative decision about which parameters to be optimized and how to balance them before any data assimilation procedure, we establish the dynamic model for emission rates with the constraint of diurnal profile shape and extend the state vector of atmospheric transport model so that the emission rates are included. Then, a theoretical approach, based on Kalman filter and smoother and their ensemble cases, to evaluate the potential improvement is introduced. By singular value decomposition, the efficiency of observations to optimize initial state and emission rates of the

  15. Tritium/tritiated water within atmosphere-plant-soil-hydrosphere system

    International Nuclear Information System (INIS)

    The work has as purpose to highlight tritium/tritiated water participation in processes within atmosphere-plant-soil-hydrosphere system. As a hydrogen's isotope, tritium is fully found in atmosphere-hydrosphere and vegetation-environment-human, and for that reason it has to be supervised and monitored, although it has a small radiotoxicity. This work is structured on the following problems: - tritium and tritiated water sources; - tritium/tritiated water involvement in natural physico-chemical and biologic processes; - tritium cycle within soil-plant-atmosphere-hydrosphere system; - tritium activity measurement in atmosphere and hydrosphere and tritium monitoring. (authors)

  16. TRADOS - an air trajectory dose model for long range transport of radioactive release to the atmosphere

    International Nuclear Information System (INIS)

    A model for estimating radiation doses resulting from long range atmospheric transport of released radionuclides in accidents is precented. The model (TRADOS) is able to treat changing diffusion conditions. For example the plume can be exposed to temporary rain, changes in turbulence and mixing depth. This can result in considerable changes in individual doses. The method is applied to an example trajectory and the doses caused by a serious reactor accident are calculated

  17. Quantifying the relationship between atmospheric transport and the chemical composition of precipitation on Bermuda

    OpenAIRE

    Moody, Jennie L.; Galloway, James N.

    2011-01-01

    In an effort to investigate the influence of different atmospheric flow patterns on thecomposition of precipitation on the island of Bermuda, a cluster analysis of atmospherictrajectories was performed to identify periods of similar transport. The cluster analysistechnique represents a relatively objective alternative to the more subjective method ofclassifying trajectories according to compass sector. Data were stratified into two broadseasons, defined as a warm (April-September) and a cool ...

  18. Adsorption and reaction of trace gas-phase organic compounds on atmospheric water film surfaces: a critical review.

    Science.gov (United States)

    Donaldson, D J; Valsaraj, Kalliat T

    2010-02-01

    The air-water interface in atmospheric water films of aerosols and hydrometeors (fog, mist, ice, rain, and snow) presents an important surface for the adsorption and reaction of many organic trace gases and gaseous reactive oxidants (hydroxyl radical (OH(.)), ozone (O(3)), singlet oxygen (O(2)((1)Delta(g))), nitrate radicals (NO(3)(.)), and peroxy radicals (RO(2)(.)). Knowledge of the air-water interface partition constant of hydrophobic organic species is necessary for elucidating the significance of the interface in atmospheric fate and transport. Various methods of assessing both experimental and theoretical values of the thermodynamic partition constant and adsorption isotherm are described in this review. Further, the reactivity of trace gases with gas-phase oxidants (ozone and singlet oxygen) at the interface is summarized. Oxidation products are likely to be more water-soluble and precursors for secondary organic aerosols in hydrometeors. Estimation of characteristic times shows that heterogeneous photooxidation in water films can compete effectively with homogeneous gas-phase reactions for molecules in the atmosphere. This provides further support to the existing thesis that reactions of organic compounds at the air-water interface should be considered in gas-phase tropospheric chemistry. PMID:20058916

  19. The Coupled Mars Dust and Water Cycles: Understanding How Clouds Affect the Vertical Distribution and Meridional Transport of Dust and Water.

    Science.gov (United States)

    Kahre, M. A.

    2015-01-01

    The dust and water cycles are crucial to the current Martian climate, and they are coupled through cloud formation. Dust strongly impacts the thermal structure of the atmosphere and thus greatly affects atmospheric circulation, while clouds provide radiative forcing and control the hemispheric exchange of water through the modification of the vertical distributions of water and dust. Recent improvements in the quality and sophistication of both observations and climate models allow for a more comprehensive understanding of how the interaction between the dust and water cycles (through cloud formation) affects the dust and water cycles individually. We focus here on the effects of clouds on the vertical distribution of dust and water, and how those vertical distributions control the net meridional transport of water. For this study, we utilize observations of temperature, dust and water ice from the Mars Climate Sounder (MCS) on the Mars Reconnaissance Orbiter (MRO) combined with the NASA ARC Mars Global Climate Model (MGCM). We demonstrate that the magnitude and nature of the net meridional transport of water between the northern and southern hemispheres during NH summer is sensitive to the vertical structure of the simulated aphelion cloud belt. We further examine how clouds influence the atmospheric thermal structure and thus the vertical structure of the cloud belt. Our goal is to identify and understand the importance of radiative/dynamic feedbacks due to the physical processes involved with cloud formation and evolution on the current climate of Mars.

  20. 78 FR 70076 - Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and...

    Science.gov (United States)

    2013-11-22

    ... COMMISSION Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and... Guidance (LR-ISG), LR-ISG-2012-02, ``Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric... availability was published in the Federal Register on June 22, 2010 (75 FR 35510). The NRC staff has...

  1. ETEX symposium on long-range atmospheric transport, model verification and emergency response. Proceedings

    International Nuclear Information System (INIS)

    Experience has shown that industrial accidents causing a release of harmful material to the atmosphere can have consequences extending to hundreds and even thousands of kilometres. A variety of long-range atmospheric transport models have been established in different countries for application in emergency management, but their quality can only be assessed with difficulty. The Chernobyl accident data have been used retrospectively for model validation, but the source term associated with it is uncertain and this limits the values for model evaluation purposes. For these reasons a follow-up study called European Tracer Experiment (ETEX), jointly organised by the European Commission's Joint Research Centre (EC JRC), the International Atomic Energy Agency (IAEA) and the World Meteorology Organization (WMO), started in 1992. The objectives of ETEX were to conduct a long-range atmospheric tracer experiment; to test the capability of institutes responsible for emergency response to produce forecasts in real-time; to evaluate the validity of their forecasts and to assemble a database which allows the evaluation of long-range atmospheric dispersion models in general. The ETEX Symposium on Long-range Atmospheric Transport, Model Verification and Emergency Response was held in Vienna, 13 - 16 May 1997. World-wide interest in the topics was demonstrated by 90 participants coming from 24 European countries including Australia, Canada, Japan, Russia and the United States. The audience was made up of ETEX participants, International Agencies, Meteorological Services and the modelling community. The 56 presentations gave a summary of the state of the art of forecasting pollutant dispersion in case of a major accidental release to the atmosphere. The Proceedings of the Symposium summarises the results of this successful project and gives conclusions and recommendations. Detailed descriptions of the project, the experimental and modelling results will be published in separate

  2. Computational study of effect of water finger on ion transport through water-oil interface

    Science.gov (United States)

    Kikkawa, Nobuaki; Wang, Lingjian; Morita, Akihiro

    2016-07-01

    When an ion transports from water to oil through water-oil interface, it accompanies hydrated water molecules and transiently forms a chain of water, called "water finger." We thoroughly investigated the role of the water finger in chloride ion transport through water-dichloromethane interface by using molecular dynamics technique. We developed a proper coordinate w to describe the water finger structure and calculated the free energy landscape and the friction for the ion transport as a function of ion position z and the water finger coordinate w. It is clearly shown that the formation and break of water finger accompanies an activation barrier for the ion transport, which has been overlooked in the conventional free energy curve along the ion position z. The present analysis of the friction does not support the hypothesis of augmented local friction (reduced local diffusion coefficient) at the interface. These results mean that the experimentally observed rate constants of interfacial ion transfer are reduced from the diffusion-limited one because of the activation barrier associated to the water finger, not the anomalous local diffusion. We also found that the nascent ion just after the break of water finger has excessive hydration water than that in the oil phase.

  3. 3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

    OpenAIRE

    Späth, Florian; Behrendt, Andreas; Muppa, Shravan Kumar; Metzendorf, Simon; Riede, Andrea; Wulfmeyer, Volker

    2016-01-01

    High-resolution three-dimensional (3-D) water vapor data of the atmospheric boundary layer (ABL) are required to improve our understanding of land–atmosphere exchange processes. For this purpose, the scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) was developed as well as new analysis tools and visualization methods. The instrument determines 3-D fields of the atmospheric water vapor number density with a temporal resolution of a few secon...

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

    OpenAIRE

    P. Sundarambal; P. Tkalich; Balasubramanian, R

    2010-01-01

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

  5. A land surface scheme for atmospheric and hydrologic models: SEWAB (Surface Energy and Water Balance)

    Energy Technology Data Exchange (ETDEWEB)

    Mengelkamp, H.T.; Warrach, K.; Raschke, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

    1997-12-31

    A soil-vegetation-atmosphere-transfer scheme is presented here which solves the coupled system of the Surface Energy and Water Balance (SEWAB) equations considering partly vegetated surfaces. It is based on the one-layer concept for vegetation. In the soil the diffusion equations for heat and moisture are solved on a multi-layer grid. SEWAB has been developed to serve as a land-surface scheme for atmospheric circulation models. Being forced with atmospheric data from either simulations or measurements it calculates surface and subsurface runoff that can serve as input to hydrologic models. The model has been validated with field data from the FIFE experiment and has participated in the PILPS project for intercomparison of land-surface parameterization schemes. From these experiments we feel that SEWAB reasonably well partitions the radiation and precipitation into sensible and latent heat fluxes as well as into runoff and soil moisture Storage. (orig.) [Deutsch] Ein Landoberflaechenschema wird vorgestellt, das den Transport von Waerme und Wasser zwischen dem Erdboden, der Vegetation und der Atmosphaere unter Beruecksichtigung von teilweise bewachsenem Boden beschreibt. Im Erdboden werden die Diffusionsgleichungen fuer Waerme und Feuchte auf einem Gitter mit mehreren Schichten geloest. Das Schema SEWAB (Surface Energy and Water Balance) beschreibt die Landoberflaechenprozesse in atmosphaerischen Modellen und berechnet den Oberflaechenabfluss und den Basisabfluss, die als Eingabedaten fuer hydrologische Modelle genutzt werden koennen. Das Modell wurde mit Daten des FIFE-Experiments kalibriert und hat an Vergleichsexperimenten fuer Landoberflaechen-Schemata im Rahmen des PILPS-Projektes teilgenommen. Dabei hat sich gezeigt, dass die Aufteilung der einfallenden Strahlung und des Niederschlages in den sensiblen und latenten Waermefluss und auch in Abfluss und Speicherung der Bodenfeuchte in SEWAB den beobachteten Daten recht gut entspricht. (orig.)

  6. Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

    Directory of Open Access Journals (Sweden)

    H. Lei

    2013-04-01

    Full Text Available Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry. The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg in three forms: elemental mercury (Hg(0, reactive mercury (Hg(II, and particulate mercury (PHg. Emissions of mercury include those from human, land, ocean, biomass burning and volcano related sources. Land emissions are calculated based on surface solar radiation flux and skin temperature. A simplified air–sea mercury exchange scheme is used to calculate emissions from the oceans. The chemistry mechanism includes the oxidation of Hg(0 in gaseous phase by ozone with temperature dependence, OH, H2O2 and chlorine. Aqueous chemistry includes both oxidation and reduction of Hg(0. Transport and deposition of mercury species are calculated through adapting the original formulations in CAM-Chem. The CAM-Chem model with mercury is driven by present meteorology to simulate the present mercury air quality during the 1999–2001 periods. The resulting surface concentrations of total gaseous mercury (TGM are then compared with the observations from worldwide sites. Simulated wet depositions of mercury over the continental United States are compared to the observations from 26 Mercury Deposition Network stations to test the wet deposition simulations. The evaluations of gaseous concentrations and wet deposition confirm a strong capability for the CAM-Chem mercury mechanism to simulate the atmospheric mercury cycle. The results also indicate that mercury pollution in East Asia and Southern Africa is very significant with TGM concentrations above 3.0 ng m−3. The comparison to wet deposition indicates that wet deposition patterns of

  7. Regulation of radionuclides discharges to the atmosphere and emissions to the water from Ukraine NPPs

    International Nuclear Information System (INIS)

    The possible order of radionuclides discharges to the atmosphere and emissions to the water from Ukraine NPPs regulation is given allowance for laws and norms of Ukraine and ICRP and IAEA guidelines. For definition of a dose relevant to marginal discharges to the atmosphere and emissions to the water of separate radionuclides are counted dose coefficients (Sv/Bg). Considered three critical age groups: the babies (up to 1 year), children (till 10 years) and adult. The age group being critical for discharges to the atmosphere and emissions to the water are determined. The radionuclides producing the greatest contribution to a dose are determined. Guidelines on calculation of marginal radionuclides discharges to the atmosphere and emissions to the water of Ukraine NPPs are given. Matching of doses from actual radionuclides discharges to the atmosphere and emissions to the water of Ukraine NPPs with quotas, assigned in RSNU-97 is carried out

  8. Comparing Stable Water Isotope Variation in Atmospheric Moisture Observed over Coastal Water and Forests

    Science.gov (United States)

    Lai, C. T.; Rambo, J. P.; Welp, L. R.; Bible, K.; Hollinger, D. Y.

    2014-12-01

    Stable oxygen (δ18O) and hydrogen (δD) isotopologues of atmospheric moisture are strongly influenced by large-scale synoptic weather cycles, surface evapotranspiration and boundary layer mixing. Atmospheric water isotope variation has been shown to empirically relate to relative humidity (Rh) of near surface moisture, and to a less degree, air temperature. Continuous δ18O and δD measurements are becoming more available, providing new opportunities to investigate processes that control isotope variability. This study shows the comparison of δ18O and δD measured at a continental location and over coastal waters for 3 seasons (spring to fall, 2014). The surface moisture isotope measurements were made using two LGR spectroscopy water vapor isotope analyzers (Los Gatos Research Inc.), one operated in an old-growth coniferous forest at Wind River field station, WA (45.8205°N, 121.9519°W), and another sampling marine air over seawater at the Scripps Pier in San Diego, CA (32.8654°N, 117.2536°W), USA. Isotope variations were measured at 1Hz and data were reported as hourly averages with an overall accuracy of ±0.1‰ for δ18O, ±0.5‰ for δ2H. Day-to-day variations in δ18O and δD are shown strongly influenced by synoptic weather events at both locations. Boundary layer mixing between surface moisture and the dry air entrained from the free troposphere exerts a midday maximum and a consistent diel pattern in deuterium excess (dx). At the forest site, surface moisture also interacts with leaf water through transpiration during the day and re-equilibration at night. The latter occurs by retro-diffusion of atmospheric H2O molecules into leaf intercellular space, which becomes intensified as Rh increaes after nightfall, and continues until sunrise, to counter-balance the evaporative isotopic enrichment in leaf water on a daily basis. These vegetation effects lead to negative dx values consistently observed at nighttime in this continental location that were not

  9. Water Transport Models of Moisture Absorption and Sweat Discharge Yarns

    Institute of Scientific and Technical Information of China (English)

    WANG Fa-ming; ZHOU Xiao-hong; WANG Shan-yuan

    2008-01-01

    An important property of moisture absorption and sweat discharge yams is their water transport property. In the paper, two water transport models of moisture absorption and sweat discharge yams were developed to investigate the influence factors on their wicking rate. In parallel Column Pores Model, wicking rate is determined by the equivalent capillary radius R and length of the capillary tube L. In Pellets Accumulation Model, wicking rate is decided by the capillary radius r and length of the fiber unit assemble L0.

  10. Effects of atmospheric water on the optical properties of soot aerosols with different mixing states

    International Nuclear Information System (INIS)

    Soot aerosols have become the second most important contributor to global warming after carbon dioxide in terms of direct forcing, which is the dominant absorber of visible solar radiation. The optical properties of soot aerosols depend strongly on the mixing mechanism of black carbon with other aerosol components and its hygroscopic properties. In this study, the effects of atmospheric water on the optical properties of soot aerosols have been investigated using a superposition T-matrix method that accounts for the mixing mechanism of soot aerosols with atmospheric water. The dramatic changes in the optical properties of soot aerosols were attributed to its different mixing states with atmospheric water (externally mixed, semi-embedded mixed, and internally mixed). Increased absorption is accompanied by a larger increase in scattering, which is reflected by the increased single scattering albedo. The asymmetry parameter also increased when increasing the atmospheric water content. Moreover, atmospheric water intensified the radiative absorption enhancement attributed to the mixing states of the soot aerosols, with values ranging from 1.5 to 2.5 on average at 0.870 μm. The increased absorption and scattering ability of soot aerosols, which is attributed to atmospheric water, exerted an opposing effect on climate change. These findings should improve our understanding of the effects of atmospheric water on the optical properties of soot aerosols and their effects on climate. The mixing mechanism for soot aerosols and atmospheric water is important when evaluating the climate effects of soot aerosols, which should be explicitly considered in radiative forcing models. - Highlights: • Effects of atmospheric water on optical properties of soot aerosols are investigated. • Increased absorption is accompanied by a larger increase in scattering. • Atmospheric water intensified the absorption enhancement due the mixing states

  11. A Test of Sensitivity to Convective Transport in a Global Atmospheric CO2 Simulation

    Science.gov (United States)

    Bian, H.; Kawa, S. R.; Chin, M.; Pawson, S.; Zhu, Z.; Rasch, P.; Wu, S.

    2006-01-01

    Two approximations to convective transport have been implemented in an offline chemistry transport model (CTM) to explore the impact on calculated atmospheric CO2 distributions. GlobalCO2 in the year 2000 is simulated using theCTM driven by assimilated meteorological fields from the NASA s Goddard Earth Observation System Data Assimilation System, Version 4 (GEOS-4). The model simulates atmospheric CO2 by adopting the same CO2 emission inventory and dynamical modules as described in Kawa et al. (convective transport scheme denoted as Conv1). Conv1 approximates the convective transport by using the bulk convective mass fluxes to redistribute trace gases. The alternate approximation, Conv2, partitions fluxes into updraft and downdraft, as well as into entrainment and detrainment, and has potential to yield a more realistic simulation of vertical redistribution through deep convection. Replacing Conv1 by Conv2 results in an overestimate of CO2 over biospheric sink regions. The largest discrepancies result in a CO2 difference of about 7.8 ppm in the July NH boreal forest, which is about 30% of the CO2 seasonality for that area. These differences are compared to those produced by emission scenario variations constrained by the framework of Intergovernmental Panel on Climate Change (IPCC) to account for possible land use change and residual terrestrial CO2 sink. It is shown that the overestimated CO2 driven by Conv2 can be offset by introducing these supplemental emissions.

  12. Dynamical climatology of the NASA Langley Research Center Interactive Modeling Project for Atmospheric Chemistry and Transport (IMPACT) model

    Science.gov (United States)

    Pierce, R. Bradley; Al-Saadi, Jassim A.; Eckman, Richard S.; Fairlie, T. Duncan; Grose, William L.; Kleb, Mary M.; Natarajan, Murali; Olson, Jennifer R.

    2000-12-01

    A comparison of the NASA Langley Research Center (LaRC) Interactive Modeling Project for Atmospheric Chemistry and Transport (IMPACT) model's dynamical characteristics with assimilated data sets and observations is presented to demonstrate the ability of the model to represent the dynamical characteristics of Earth's troposphere and stratosphere. The LaRC IMPACT model is a coupled chemical/dynamical general circulation model (GCM) of the Earth's atmosphere extending from the surface to the lower mesosphere. It has been developed as a tool for assessing the effects of chemical, dynamical, and radiative coupling in the stratosphere on the Earth's climate. The LaRC IMPACT model winds and temperatures are found to be in fairly good agreement with Upper Atmospheric Research Satellite (UARS) United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures in the lower stratosphere. The model upper stratospheric zonal mean temperatures are also in good agreement with the UARS-UKMO climatology except for a cold winter pole which results from the upward extension of the cold vortex temperatures and an elevated winter stratopause in the model. The cold pole bias is consistent with the overprediction of the winter stratospheric jet strength, and is characteristic of stratospheric GCMs in general. The model northern and southern hemisphere stratospheric eddy heat and momentum fluxes are within the expected interannual variability of the UARS-UKMO climatology. The combined effects of water vapor transport, radiative, convective, and planetary boundary layer parameterizations are shown to produce tropospheric winds and circulation statistics that are in good agreement with the UARS-UKMO climatology, although the model tropopause and upper tropospheric temperatures are generally cold relative to the UARS-UKMO temperatures. Comparisons between the model and UARS-UKMO climatology indicate that the model does a reasonable job in reproducing the frequency of observed

  13. Influence of model resolution on the atmospheric transport of 10Be

    Directory of Open Access Journals (Sweden)

    A. M. Smith

    2012-07-01

    Full Text Available Understanding the transport path of the solar activity proxy 10Be from source to archive is crucial for the interpretation of its observed variability. The extent of mixing of the strong production signal has been quantified in a previous study (Heikkilä et al., 2009. In this study we perform sensitivity studies to investigate the influence of model resolution on the level of mixing and transport path of 10Be in the atmosphere using the ECHAM5-HAM aerosol-climate model. This study permits us to choose an acceptable resolution, and so minimum CPU time, to produce physically accurate reconstructions. Four model resolutions are applied: T21L19: a coarse horizontal and vertical resolution with model top at ca. 30 km, T42L31: an average horizontal and fine vertical one, T42L39: similar vertical resolution than L19 but including the middle atmosphere up to ca. 80 km and T63L47: a fine resolution horizontally and vertically with middle atmosphere. Comparison with observations suggests that a finer vertical resolution might be beneficial, although the spread between observations was much larger than between the four model runs. A full validation of the resolutions is not possible with the limited number of observations available. In terms of atmospheric mixing the differences became more distinguishable. All resolutions agreed that the main driver of deposition variability is the stratospheric 10Be (total contribution 68% which is transported into the troposphere at latitudes 30–50°. In the troposphere the model resolutions deviated largely in the dispersion of the stratospheric component over latitude. The finest resolution (T63L47 predicted the least dispersion towards low latitudes but the most towards the poles, whereas the coarsest resolution (T21L19 suggested the opposite. The tropospheric components of 10Be differed less between the four model runs. The largest differences were found in the polar tropospheric components, which contribute the

  14. Characteristics of heat transport in porous media with water infiltration

    International Nuclear Information System (INIS)

    In this paper heat and water transports in porous media with waster infiltration are discussed experimentally and theoretically. The distributions of water content and temperature were predicted for one- and tow-dimensional porous media, based on a model that there is thermal equilibrium between the water and the matrix at any specific space. The predicted temperature distributions were compared of the experimental results obtained using various glass bead sizes. A larger bead size has a faster infiltration rate and forms a wider infiltration layer, especially to the direction of gravity. But the heated layer does not extend so wide as the infiltration layer because the temperature of water infiltrating gradually drops due to heat transport at upstream

  15. Tube transport of water vapor with condensation and desorption

    OpenAIRE

    Nordbo, Annika; Kekäläinen, Pekka; Siivola, Erkki.; Lehto, Roope; Vesala , Timo; Timonen, Jussi

    2013-01-01

    Attenuation and delay of active tracers in tube transport is an important current problem, but its full explanation is still lacking. To this end a model is introduced, where part of a tracer undergoes condensation and evaporation, treated as a diffusion-type process, in addition to Taylor dispersion. Condensation of water was verified by high-speed imaging, and the model solution fitted the breakthrough curves of laboratory measurements with pulses of water vapor of varying relat...

  16. Bacteria in the global atmosphere – Part 2: Modeling of emissions and transport between different ecosystems

    Directory of Open Access Journals (Sweden)

    M. G. Lawrence

    2009-12-01

    Full Text Available Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulate the global transport of bacteria, represented as 1 μm and 3 μm diameter spherical solid particle tracers in a general circulation model. We investigate factors influencing residence time and distribution of the particles, including emission region, cloud condensation nucleus activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region, particulate diameter, and season. We find that the seasonal variation in atmospheric residence time is insufficient to explain by itself the observed seasonal variation in concentrations of particulate airborne culturable bacteria, indicating that this variability is mainly driven by seasonal variations in culturability and/or emission strength. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using a maximum likelihood estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria-containing particles to the atmosphere to be 7.6×1023–3.5×1024 a−1, originating mainly from grasslands, shrubs and crops. We estimate the mass of emitted bacteria- to be 40–1800 Gg a−1, depending on the mass fraction of bacterial cells in the particles. In order to improve understanding of this topic, more measurements of the bacterial content of the air and of the rate of surface-atmosphere exchange of bacteria will be necessary. Future observations in wetlands, hot deserts, tundra, remote glacial and coastal regions and over oceans will be

  17. Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V. Jr.; Simonen, C.A.; Burk, K.W.

    1994-02-01

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses that individuals may have received from operations at the Hanford Site since 1944. This report deals specifically with the atmospheric transport model, Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). RATCHET is a major rework of the MESOILT2 model used in the first phase of the HEDR Project; only the bookkeeping framework escaped major changes. Changes to the code include (1) significant changes in the representation of atmospheric processes and (2) incorporation of Monte Carlo methods for representing uncertainty in input data, model parameters, and coefficients. To a large extent, the revisions to the model are based on recommendations of a peer working group that met in March 1991. Technical bases for other portions of the atmospheric transport model are addressed in two other documents. This report has three major sections: a description of the model, a user`s guide, and a programmer`s guide. These sections discuss RATCHET from three different perspectives. The first provides a technical description of the code with emphasis on details such as the representation of the model domain, the data required by the model, and the equations used to make the model calculations. The technical description is followed by a user`s guide to the model with emphasis on running the code. The user`s guide contains information about the model input and output. The third section is a programmer`s guide to the code. It discusses the hardware and software required to run the code. The programmer`s guide also discusses program structure and each of the program elements.

  18. Eolian transport of geogenic hexavalent chromium to ground water

    Science.gov (United States)

    Wood, W.W.; Clark, D.; Imes, J.L.; Councell, T.B.

    2010-01-01

    A conceptual model of eolian transport is proposed to address the widely distributed, high concentrations of hexavalent chromium (Cr+6) observed in ground water in the Emirate of Abu Dhabi, United Arab Emirates. Concentrations (30 to more than 1000 μg/L Cr+6) extend over thousands of square kilometers of ground water systems. It is hypothesized that the Cr is derived from weathering of chromium-rich pyroxenes and olivines present in ophiolite sequence of the adjacent Oman (Hajar) Mountains. Cr+3 in the minerals is oxidized to Cr+6 by reduction of manganese and is subsequently sorbed on iron and manganese oxide coatings of particles. When the surfaces of these particles are abraded in this arid environment, they release fine, micrometer-sized, coated particles that are easily transported over large distances by wind and subsequently deposited on the surface. During ground water recharge events, the readily soluble Cr+6 is mobilized by rain water and transported by advective flow into the underlying aquifer. Chromium analyses of ground water, rain, dust, and surface (soil) deposits are consistent with this model, as are electron probe analyses of clasts derived from the eroding Oman ophiolite sequence. Ground water recharge flux is proposed to exercise some control over Cr+6 concentration in the aquifer.

  19. CFD Model of Water Droplet Transport for ISS Hygiene Activity

    Science.gov (United States)

    Son, Chang H.

    2011-01-01

    The goal of the study is to assess the impacts of free water propagation in the Waste and Hygiene Compartment (WHC). Free water can be generated inside the WHC in small quantities due to crew hygiene activity. To mitigate potential impact of free water in Node 3 cabin the WHC doorway is enclosed by a waterproof bump-out, Kabin, with openings at the top and bottom. At the overhead side of the rack, there is a screen that prevents large drops of water from exiting. However, as the avionics fan in the WHC causes airflow toward the deck side of the rack, small quantities of free water may exit at the bottom of the Kabin. A Computational Fluid Dynamics (CFD) analysis of Node 3 cabin airflow made possible to identify the paths of water transport. The Node 3 airflow was computed for several ventilation scenarios. To simulate the droplet transport the Lagrangian discrete phase approach was used. Various initial droplet distributions were considered in the study. The droplet diameter was varied in the range of 2-20 mm. The results of the computations showed that most of the drops fall to the rack surface not far from the WHC curtain. The probability of the droplet transport to the adjacent rack surface with electronic equipment was predicted.

  20. Implementation of a convective atmospheric boundary layer scheme in a tropospheric chemistry transport model

    Science.gov (United States)

    Wang, K.-Y.; Pyle, J. A.; Sanderson, M. G.; Bridgeman, C.

    1999-10-01

    A convective atmospheric boundary layer (ABL) scheme for the transport of trace gases in the lower troposphere has been implemented from the Community Climate Model, Version 2 [Hack et al., 1993] into a tropospheric chemistry transport model [Wang, 1998]. The atmospheric boundary layer scheme includes the calculation of atmospheric radiative transfer, surface energy balance, and land surface temperature and has a specified annual variation of sea surface temperature. The calculated diurnal variation of the height of the boundary layer is similar to the results of Troen and Mahrt [1986] and is in a good agreement with Holtslag and Boville [1993]. The modeled height of the boundary layer shows a seasonal shift between land and sea in the Northern Hemisphere. In summer (June-July-August), the height of the boundary layer is deeper over land (850-2250 m) and shallower over sea (50-850 m); while in winter (December-January-February), it is shallower over land (50-850 m) and deeper over sea (850-2850 m). The coupled ABL-chemical transport model is verified against measurements of radon 222 and methane. Comparison of the coupled model with a non-ABL model indicates significant differences between these model simulations and a better agreement between the coupled model and measurements. There is a significant effect on the trace gas distribution when the ABL model is compared with the non-ABL schemes. For example, the ABL scheme shows more O3 transported from the middle troposphere down to the surface, while more CO is pumped up from the surface into the middle troposphere. The seasonal cycle of modeled CH4 is significantly improved with the inclusion of the new ABL scheme, especially in regions which are not remote from methane sources.

  1. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    OpenAIRE

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi Kumar

    2015-01-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3-D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a '...

  2. Pollution transport in the Boden garrison storm water

    OpenAIRE

    Udén, Jonathan

    2013-01-01

    A study concerning the pollution transport in storm water pipes. Yearly volume and maximum flow is calculated for a number of outlets, from an industrial area in northern Sweden. The pipes are elso evaluated concerning their ability to handle bigger oil spills.

  3. Measuring Transport of Water Across the Peritoneal Membrane

    Czech Academy of Sciences Publication Activity Database

    Asghar, R. B.; Diskin, A. M.; Španěl, Patrik; Smith, D.; Davies, S. J.

    2003-01-01

    Roč. 64, - (2003), s. 1911-1915. ISSN 0085-2538 R&D Projects: GA ČR GA202/03/0827 Institutional research plan: CEZ:AV0Z4040901 Keywords : deuterium * total body water * solute transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.302, year: 2003

  4. Water Transport in Trees--An Artificial Laboratory Tree

    Science.gov (United States)

    Susman, K.; Razpet, N.; Cepic, M.

    2011-01-01

    Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

  5. Classroom Techniques to Illustrate Water Transport in Plants

    Science.gov (United States)

    Lakrim, Mohamed

    2013-01-01

    The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

  6. The Potential Importance of Non-Local, Deep Transport on the Energetics, Momentum, Chemistry, and Aerosol Distributions in the Atmospheres of Earth, Mars and Titan

    CERN Document Server

    Rafkin, Scot

    2010-01-01

    A review of non-local, deep transport mechanisms in the atmosphere of Earth provides a good foundation for examining whether similar mechanisms are operating in the atmospheres of Mars and Titan. On Earth, deep convective clouds in the tropics constitute the upward branch of the Hadley Cell and provide a conduit through which energy, moisture, momentum, aerosols and chemical species are moved from the boundary layer to the upper troposphere and lower stratosphere. This transport produces mid-tropospheric minima in quantities such as water vapor and moist static energy and maxima where the clouds detrain. Analogs to this terrestrial transport are found in the strong and deep thermal circulations associated with topography on Mars and with Mars dust storms. Observations of elevated dust layers on Mars further support the notion that non-local deep transport is an important mechanism in the atmosphere of Mars. On Titan, the presence of deep convective clouds almost assures that non-local, deep transport is occur...

  7. Physical Hydrography and Algal Bloom Transport in Hong Kong Waters

    Institute of Scientific and Technical Information of China (English)

    KUANG Cui-ping; LEE Joseph H.W.

    2005-01-01

    In sub-tropical coastal waters around Hong Kong, algal blooms and red tides are usually first sighted in the Mirs Bay, in the eastern waters of Hong Kong. A calibrated three-dimensional hydrodynamic model for the Pearl River Estuary (Delft3D) has been applied to the study of the physical hydrography of Hong Kong waters and its relationship with algal bloom transport patterns in the dry and wet seasons. The general 3D hydrodynamic circulation and salinity structure in the partially-mixed estuary are presented. Extensive numerical surface drogue tracking experiments are performed for algal blooms that are initiated in the Mirs Bay under different seasonal, wind and tidal conditions. The probability of bloom impact on the Victoria Harbour and nearby urban coastal waters is estimated. The computations show that: I) In the wet season (May~August), algal blooms initiated in the Mirs Bay will move in a clockwise direction out of the bay, and be transported away from Hong Kong due to SW monsoon winds which drive the SW to NE coastal current; ii) In the dry season (November~April), algal blooms initiated in the northeast Mirs Bay will move in an anti-clockwise direction and be carried away into southern waters due to the NE to SW coastal current driven by the NE monsoon winds; the bloom typically flows past the east edge of the Victoria Harbour and nearby waters. Finally, the role of hydrodynamic transport in an important episodic event - the spring 1998 massive red tide - is quantitatively examined. It is shown that the strong NE to E wind during late March to early April, coupled with the diurnal tide at the beginning of April, significantly increased the probability of bloom transport into the Port Shelter and East Lamma Channel, resulting in the massive fish kill. The results provide a basis for risk assessment of harmful algal bloom (HAB) impact on urban coastal waters around the Victoria Habour.

  8. Influence of atmospheric transport patterns on xenon detections at the CTBTO radionuclide network

    Science.gov (United States)

    Krysta, Monika; Kusmierczyk-Michulec, Jolanta

    2016-04-01

    In order to fulfil its task of monitoring for signals emanating from nuclear explosions, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates global International Monitoring System (IMS) comprising seismic, infrasound, hydroacoustic and radionuclide measurement networks. At present, 24 among 80 radionuclide stations foreseen by the Comprehensive Nuclear-Test-Ban Treaty (CTBT) are equipped with certified noble gas measurement systems. Over a past couple of years these systems collected a rich set of measurements of radioactive isotopes of xenon. Atmospheric transport modelling simulations are crucial to an assessment of the origin of xenon detected at the IMS stations. Numerous studies undertaken in the past enabled linking these detections to non Treaty-relevant activities and identifying main contributors. Presence and quantity of xenon isotopes at the stations is hence a result of an interplay of emission patterns and atmospheric circulation. In this presentation we analyse the presence or absence of radioactive xenon at selected stations from an angle of such an interplay. We attempt to classify the stations according to similarity of detection patterns, examine seasonality in those patterns and link them to large scale or local meteorological phenomena. The studies are undertaken using crude hypotheses on emission patterns from known sources and atmospheric transport modelling simulations prepared with the FLEXPART model.

  9. ATMOSPHERE PROTECTION IN CASE OF EMERGENCY DURING TRANSPORTATION OF DANGEROUS CARGO

    Directory of Open Access Journals (Sweden)

    O. V. Berlov

    2016-02-01

    Full Text Available Purpose. The paper highlights the development of numerical models for prediction of atmospheric pollution in case of burning of the solid rocket propellant in a railway car, situated near the building on railway territory. These models can be used in predicting the effectiveness of neutralization upon the atmosphere protection for this type of accidents. Methodology.To solve this problem the numerical models based on the use of Navier-Stokes equations, to determine the velocity field of the wind flow near cars and buildings, and contaminants-transfer equations in the atmosphere were developed. For the numerical integration of pollutant transport equation was used implicit «change – triangle» difference scheme. When constructing a difference scheme physical and geometric cleavage of the transfer equation is carried out in four steps. Unknown value of pollutant concentration at each step of cleavage is determined by the explicit scheme – the method of «point-to-point computation». For the numerical integration of the Navier-Stokes equations are used implicit difference schemes. When carrying out computing experiment also takes into account: the velocity profile of wind flow; interaction between the building and the wind flow and flame jet of solid rocket propellant; the presence of a railroad car; inside which there is a source of pollution; instability of pollutant emissions. On the basis of constructed numerical models was performed the computer experiment for assessing the level of air pollution at dangerous cargo rail transportation in case of emergency at railway territory.The application calculations for the timely combustion products neutralization of solid rocket propellant were carried out. Findings. The numerical models that let promptly calculate air contamination in case of emergency during solid rocket propellant transportation, as well as calculate the rational parameters of pollutant neutralization process were developed by

  10. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    Science.gov (United States)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  11. Characterization of atmospheric aerosols in Ile-de-France: Local contribution and Long range transport

    International Nuclear Information System (INIS)

    Atmospheric aerosols interact directly in a great number of processes related to climate change and public health, modifying the energy budget and partly determining the quality of the air we breathe. In my PhD, I chose to study the perturbation, if not the aggravation, of the living conditions in Ile-de-France associated to aerosol transport episodes in the free troposphere. This situation is rather frequent and still badly known. To achieve my study, I developed the observation platform 'TReSS' Transportable Remote Sensing Station, whose instruments were developed at the Laboratoire de Meteorology Dynamique by the LiMAG team. 'TReSS' consists of a new high-performance 'Mini-Lidar' and of two standard radiometers: a sun photometer and a thermal infrared radiometer. The principle of my experimental approach is the synergy of the vertical Lidar profiles and the particle size distributions over the column, obtained by the 'Almucantar' inversion of sun photometer data. The new 'Lidar and Almucantar' method characterizes the vertical distribution by layer and the optical micro-physical properties of the local and transported aerosols. Firstly, I undertook the characterization of the Paris aerosol, mainly of anthropogenic origin. Their radiative properties were analyzed in the daily and yearly scales. Then, I conducted a statistical multi-year study of transport episodes and a two-week study case, representative of a succession of desert dust intrusion in Ile-de-France. My PhD work concludes by a study on the impact of biomass burning aerosols during the heat wave on August 2003. I study the impact of the transported aerosols into the local radiative budget and the possible consequences on the diurnal cycle of the atmospheric boundary layer. (author)

  12. Bacteria in the global atmosphere – Part 2: Modelling of emissions and transport between different ecosystems

    Directory of Open Access Journals (Sweden)

    S. M. Burrows

    2009-05-01

    Full Text Available Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulated the global transport of bacterial cells, represented as 1μm diameter spherical solid particle tracers, in a chemistry-climate model. We investigated the factors influencing residence time and distribution of the particles, including emission region, CCN activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region and by season. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using an optimal estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria to the atmosphere to be 1400 Gg per year with an upper bound of 4600 Gg per year, originating mainly from grasslands, shrubs and crops. In order to improve understanding of this topic, more measurements of the bacterial content of the air will be necessary. Future measurements in wetlands, sandy deserts, tundra, remote glacial and coastal regions and over oceans will be of particular interest.

  13. Error characterization of CO2 vertical mixing in the atmospheric transport model WRF-VPRM

    Directory of Open Access Journals (Sweden)

    U. Karstens

    2011-10-01

    Full Text Available One of the dominant uncertainties in inverse estimates of regional CO2 surface-atmosphere fluxes is related to model errors in vertical transport within the planetary boundary layer (PBL. In this study we present the results from a synthetic experiment using the atmospheric model WRF-VPRM to realistically simulate transport of CO2 for large parts of the European continent at 10 km spatial resolution. To elucidate the impact of vertical mixing error on modeled CO2 mixing ratios we simulated a month during the growing season (August 2006 with different commonly used parameterizations of the PBL (Mellor-Yamada-Janjic (MYJ and Yonsei-University (YSU scheme. To isolate the effect of transport errors we prescribed the same CO2 surface fluxes for both simulations. Differences in simulated CO2 mixing ratios (model bias were on the order of 3 ppm during daytime with larger values during night. We present a simple method to reduce this bias by 70–80% when the true height of the mixed layer is known.

  14. Error characterization of CO2 vertical mixing in the atmospheric transport model WRF-VPRM

    Directory of Open Access Journals (Sweden)

    U. Karstens

    2012-03-01

    Full Text Available One of the dominant uncertainties in inverse estimates of regional CO2 surface-atmosphere fluxes is related to model errors in vertical transport within the planetary boundary layer (PBL. In this study we present the results from a synthetic experiment using the atmospheric model WRF-VPRM to realistically simulate transport of CO2 for large parts of the European continent at 10 km spatial resolution. To elucidate the impact of vertical mixing error on modeled CO2 mixing ratios we simulated a month during the growing season (August 2006 with different commonly used parameterizations of the PBL (Mellor-Yamada-Janjić (MYJ and Yonsei-University (YSU scheme. To isolate the effect of transport errors we prescribed the same CO2 surface fluxes for both simulations. Differences in simulated CO2 mixing ratios (model bias were on the order of 3 ppm during daytime with larger values at night. We present a simple method to reduce this bias by 70–80% when the true height of the mixed layer is known.

  15. Particle size distribution of halogenated flame retardants and implications for atmospheric deposition and transport.

    Science.gov (United States)

    Okonski, Krzysztof; Degrendele, Céline; Melymuk, Lisa; Landlová, Linda; Kukučka, Petr; Vojta, Šimon; Kohoutek, Jiří; Čupr, Pavel; Klánová, Jana

    2014-12-16

    This study investigates the distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and a group of novel flame retardants (NFRs) on atmospheric aerosols. Two high volume cascade impactors were used to collect particulate fractions of ambient air over a one year period at urban and rural sites. The majority of FRs were found on the finest aerosols (<0.95 μm). Concentrations of HBCD were higher than those of ΣPBDEs. Moreover, we noted seasonality and spatial differences in particle size distributions, yet a large portion of the observed differences were due to differences in particulate matter (PM) itself. When normalized by PM, the size distributions of the FRs exhibited much greater heterogeneity. Differences existed between the FR distributions by molecular weight, with the higher molecular weight FRs (e.g., BDE-209, Dechlorane Plus) distributed more uniformly across all particulate size fractions. The seasonal, spatial, and compound-specific differences are of crucial importance when estimating dry and wet deposition of FRs as smaller aerosols have longer atmospheric residence times. Estimated wet and dry deposition of four representative FRs (BDE-47, BDE-209, HBCD, and Dechlorane Plus) using size-segregated aerosol data resulted in lower deposition estimates than when bulk aerosol data were used. This has implications for estimates of long-range atmospheric transport and atmospheric residence times, as it suggests that without size-specific distributions, these parameters could be underestimated for FRs. PMID:25380095

  16. Application of numerical environment system to regional atmospheric radioactivity transport simulations

    International Nuclear Information System (INIS)

    Main functions of the Numerical Environment System (NES), as a part of the Information Technology Based Laboratory (ITBL) project implemented by Japan Atomic Energy Research Institute, became available for test use purposes although the development of the system is still underway. This system consists of numerical models of meteorology and atmospheric dispersion, database necessary for model simulations, post- and pre-processors such as data conversion and visualization, and a suite of system software which provide the users with system functions through a web page access. The system utilizes calculation servers such as vector- and scalar-parallel processors for numerical model execution, a EWS which serves as a hub of the system. This system provides users in the field of nuclear emergency preparedness and atmospheric environment with easy-to-use functions of atmospheric dispersion simulations including input meteorological data preparation and visualization of simulation results. The performance of numerical models in the system was examined with observation data of long-range transported radon-222. The models in the system reproduced quite well temporal variations in the observed radon-222 concentrations in air which were caused by changes in the meteorological field in the synoptic scale. By applying the NES models in combination with the idea of backward-in-time atmospheric dispersion simulation, seasonal shift of source areas of radon-222 in the eastern Asian regions affecting the concentrations in Japan was quantitatively illustrated. (authors)

  17. Effective pollutant emission heights for atmospheric transport modelling based on real-world information

    International Nuclear Information System (INIS)

    Emission data needed as input for the operation of atmospheric models should not only be spatially and temporally resolved. Another important feature is the effective emission height which significantly influences modelled concentration values. Unfortunately this information, which is especially relevant for large point sources, is usually not available and simple assumptions are often used in atmospheric models. As a contribution to improve knowledge on emission heights this paper provides typical default values for the driving parameters stack height and flue gas temperature, velocity and flow rate for different industrial sources. The results were derived from an analysis of the probably most comprehensive database of real-world stack information existing in Europe based on German industrial data. A bottom-up calculation of effective emission heights applying equations used for Gaussian dispersion models shows significant differences depending on source and air pollutant and compared to approaches currently used for atmospheric transport modelling. - The comprehensive analysis of real-world stack data provides detailed default parameter values for improving vertical emission distribution in atmospheric modelling

  18. Decomposition of water-insoluble organic waste by water plasma at atmospheric pressure

    International Nuclear Information System (INIS)

    The water plasma was generated in atmospheric pressure with the emulsion state of 1-decanol which is a source of soil and ground water pollution. In order to investigate effects of operating conditions on the decomposition of 1-decanol, generated gas and liquid from the water plasma treatment were analysed in different arc current and 1-decanol concentration. The 1-decanol was completely decomposed generating hydrogen, carbon monoxide, carbon dioxide, methane, treated liquid and solid carbon in all experimental conditions. The feeding rate of 1- decanol emulsion was increased with increasing the arc current in virtue of enhanced input power. The generation rate of gas and the ratio of carbon dioxide to carbon monoxide were increased in the high arc current, while the generation rate of solid carbon was decreased due to enhanced oxygen radicals in the high input power. Generation rates of gas and solid carbon were increased at the same time with increasing the concentration of 1-decanol, because carbon radicals were increased without enhancement of oxygen radicals in a constant power level. In addition, the ratio of carbon dioxide to carbon monoxide was increased along with the concentration of 1-decanol due to enhanced carbon radicals in the water plasma flame.

  19. 10-year record of atmospheric composition in the high Himalayas: source, transport and impact

    Science.gov (United States)

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

    2016-04-01

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

  20. Models of coupled salt and water transport across leaky epithelia.

    Science.gov (United States)

    Weinstein, A M; Stephenson, J L

    1981-05-15

    A general formulation is presented for the verification of isotonic transport and for the assignment of a degree of osmotic coupling in any epithelial model. In particular, it is shown that the concentration of the transported fluid in the presence of exactly equal bathing media is, in general, not a sufficient calculation by which to decide the issue of isotonicity of transport. Within this framework, two epithelial models are considered: (1) A nonelectrolyte compartment model of the lateral intercellular space is presented along with its linearization about the condition of zero flux. This latter approximate model is shown to be useful in the estimation of deviation from isotonicity, intraepithelial solute polarization effects, and the capacity to transport water against a gradient. In the case of uphill water transport, some limitations of a model of fixed geometry are indicated and the advantage of modeling a compliant interspace is suggested. (2) A comprehensive model of cell and channel is described which includes the major electrolytes and the possible presence of intraepithelial gradients. The general approach to verification of isotonicity is illustrated for this numerical model. In addition, the insights about parameter dependence gained from the linear compartment model are shown to be applicable to understanding this large simulation. PMID:6264088

  1. Changes of Atmospheric Water Balance over China under the IPCC SRES A1B Scenario Based on RegCM3 Simulations

    Institute of Scientific and Technical Information of China (English)

    SUN Bo; JIANG Da-Bang

    2012-01-01

    Simulations of the Regional Climate Model Version 3 (RegCM3) under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario were employed to investigate possible decadal changes and long-term trends of annual mean atmospheric water balance components over China in the 21st century with reference to the period of 1981-2000. An evaluation showed that RegCM3 can reasonably reproduce annual evapotranspiration, precipitation, and water vapor transport over China, with a better performance for March–June. It was found that the water vapor exchange between the land surface and atmosphere would be significantly intensified in Northwest China by the mid-to late-21st century and that the region would possibly shift to a wetter or drought-mitigated state under global warming. Conversely, the water vapor exchange evidently weakened over the Tibetan Plateau and South-west China by the mid-to late-21st century. In addition, there appears to be a drier state for Northeast China and the middle and lower reaches of the Yangtze River valley by the mid-to late-21st century, with slight mitigation by the end compared with the mid-21st century. The westerly and southwesterly water vapor transport over China generally presents an increasing trend, with increasing diver-gence over the Tibetan Plateau and Northeast China, corresponding to a loss of atmospheric water vapor by water vapor transport.

  2. Energy Transport Effects in Flaring Atmospheres Heated by Mixed Particle Beams

    Science.gov (United States)

    Zharkova, Valentina; Zharkov, Sergei; Macrae, Connor; Druett, Malcolm; Scullion, Eamon

    2016-07-01

    We investigate energy and particle transport in the whole flaring atmosphere from the corona to the photosphere and interior for the flaring events on the 1st July 2012, 6 and 7 September 2011 by using the RHESSI and SDO instruments as well as high-resolution observations from the Swedish 1-metre Solar Telescope (SST3) CRISP4 (CRisp Imaging Spectro-polarimeter). The observations include hard and soft X-ray emission, chromospheric emission in both H-alpha 656.3 nm core and continuum, as well as, in the near infra-red triplet Ca II 854.2 nm core and continuum channels and local helioseismic responses (sunquakes). The observations are compared with the simulations of hard X-ray emission and tested by hydrodynamic simulations of flaring atmospheres of the Sun heated by mixed particle beams. The temperature, density and macro-velocity variations of the ambient atmospheres are calculated for heating by mixed beams and the seismic response of the solar interior to generation of supersonic shocks moving into the solar interior. We investigate the termination depths of these shocks beneath the quiet photosphere levels and compare them with the parameters of seismic responses in the interior, or sunquakes (Zharkova and Zharkov, 2015). We also present an investigation of radiative conditions modelled in a full non-LTE approach for hydrogen during flare onsets with particular focus on Balmer and Paschen emission in the visible, near UV and near IR ranges and compare them with observations. The links between different observational features derived from HXR, optical and seismic emission are interpreted by different particle transport models that will allow independent evaluation of the particle transport scenarios.

  3. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Science.gov (United States)

    Lu, X.; Naidis, G. V.; Laroussi, M.; Reuter, S.; Graves, D. B.; Ostrikov, K.

    2016-05-01

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors' vision for the emerging convergence trends across several disciplines and application domains is presented to

  4. Transport properties of water and oxygen in yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    Oxide materials that adopt the fluorite structure, such as yttria-stabilized zirconia (YSZ), play a central role in electrochemical devices, such as fuel cells and sensors, because of their high ionic conductivity. By virtue of the technological importance of such devices there exists a broad interest in understanding and enhancing mass transport processes in YSZ. In such oxides, not only does transport through the bulk play a critical role; interfaces (internal and external) have an influence, too. The effect of interfaces on the transport properties, however, is not investigated in detail, and remains in many places unclear. In this work two open questions concerning the effect of interfaces on mass transport processes in YSZ are addressed: The first issue is the phenomenon of protonic conductivity observed at low temperatures for nanocrystalline YSZ in wet atmospheres. This protonic conductivity was attributed to the high density of interfaces (grain boundaries) caused by the nanostructure, in which protonic species can be mobile. Through isotope exchange experiments with subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) the presence of hydrogen in nano-YSZ was confirmed. Questions as to which hydrogen-containing species are present and which transport path is taken in nanocrystalline YSZ were examined by means of in-situ of near-infrared (NIR) spectroscopy. The results indicate that water is adsorbed on internal surfaces, such as pores and micro-cracks. Microscopic analysis of nanocrystalline YSZ showed first indications of nanopores. The second issue concerned transport across the solidgas interface, that is the surface. To this end, oxygen isotope exchange experiments were performed on single crystal samples of yttria-stabilised zirconia under wet and dry conditions as function of oxygen partial pressure pO2 and water partial pressure pH2O with subsequent determination of the oxygen isotope profiles by ToF-SIMS. As expected, the diffusion

  5. Maintaining Atmospheric Mass and Water Balance Within Reanalysis

    Science.gov (United States)

    Takacs, Lawrence L.; Suarez, Max; Todling, Ricardo

    2015-01-01

    This report describes the modifications implemented into the Goddard Earth Observing System Version-5 (GEOS-5) Atmospheric Data Assimilation System (ADAS) to maintain global conservation of dry atmospheric mass as well as to preserve the model balance of globally integrated precipitation and surface evaporation during reanalysis. Section 1 begins with a review of these global quantities from four current reanalysis efforts. Section 2 introduces the modifications necessary to preserve these constraints within the atmospheric general circulation model (AGCM), the Gridpoint Statistical Interpolation (GSI) analysis procedure, and the Incremental Analysis Update (IAU) algorithm. Section 3 presents experiments quantifying the impact of the new procedure. Section 4 shows preliminary results from its use within the GMAO MERRA-2 Reanalysis project. Section 5 concludes with a summary.

  6. Soil physics with Python transport in the soil-plant-atmosphere system

    CERN Document Server

    Bittelli, Marco; Tomei, Fausto

    2015-01-01

    This volume presents numerical methods to solve soil physics problems using computers. It starts with the theory and then shows how to use Python code to solve the problems. Most soil physics books focus on deriving rather than solving the differential equations for mass and energy transport in the soil-plant-atmosphere continuum. The focus of this book is on solutions. Agricultural and biological scientists usually have a good working knowledge of algebra and calculus, but not of differential equations. Here numerical procedures are used to solve differential equations.

  7. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    Science.gov (United States)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

  8. Worldwide status of long range atmospheric transportation models for use in emergency situations

    International Nuclear Information System (INIS)

    This report contains the results of the work of a working group put together in order to summarize the status of long range atmospheric transportation models for use in an emergency situation in real-time mode. The most important characteristics of the various models are summarized. The models in use in the Nordic countries as well as a couple of non-Nordic models are presented in more detail. A discussion of the desired characteristics of real-time models (also referred to as Emergency Response Assisting Systems) is included

  9. Nanoscale transport of electrons and ions in water

    Science.gov (United States)

    Boynton, Paul Christopher

    The following dissertation discusses the theoretical study of water on the nanoscale, often involved with essential biological molecules such as DNA and proteins. First I introduce the study of water on the nanoscale and how experimentalists approach confinement with nanopores and nanogaps. Then I discuss the theoretical method we choose for understanding this important biological medium on the molecular level, namely classical molecular dynamics. This leads into transport mechanisms that utilize water on the nanoscale, in our case electronic and ionic transport. On the scale of mere nanometers or less electronic transport in water enters the tunneling regime, requiring the use of a quantum treatment. In addition, I discuss the importance of water in ionic transport and its known effects on biological phenomena such as ion selectivity. Water also has great influence over DNA and proteins, which are both introduced in the context of nanopore sequencing. Several techniques for nanopore sequencing are examined and the importance of protein sequencing is explained. In Chapter 2, we study the effect of volumetric constraints on the structure and electronic transport properties of distilled water in a nanopore with embedded electrodes. Combining classical molecular dynamics simulations with quantum scattering theory, we show that the structural motifs water assumes inside the pore can be probed directly by tunneling. In Chapter 3, we propose an improvement to the original sequencing by tunneling method, in which N pairs of electrodes are built in series along a synthetic nanochannel. Each current time series for each nucleobase is cross-correlated together, reducing noise in the signals. We show using random sampling of data from classical molecular dynamics, that indeed the sequencing error is significantly reduced as the number of pairs of electrodes, N, increases. In Chapter 4, we propose a new technique for de novo protein sequencing that involves translocating a

  10. Barriers to Superfast Water Transport in Carbon Nanotube Membranes

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Ritos, Konstantinos; Cruz-Chu, Eduardo R.;

    2013-01-01

    Carbon nanotube (CNT) membranes hold the promise of extraordinary fast water transport for applications such as energy efficient filtration and molecular level drug delivery. However, experiments and computations have reported flow rate enhancements over continuum hydrodynamics that contradict each...... other by orders of magnitude. We perform large scale molecular dynamics simulations emulating for the first time the micrometer thick CNTs membranes used in experiments. We find transport enhancement rates that are length dependent due to entrance and exit losses but asymptote to 2 orders of magnitude...

  11. The use of coupled atmospheric and hydrological models for water-resources management in headwater basins

    Science.gov (United States)

    Leavesley, G.; Hay, L.

    1998-01-01

    Coupled atmospheric and hydrological models provide an opportunity for the improved management of water resources in headwater basins. Issues currently limiting full implementation of coupled-model methodologies include (a) the degree of uncertainty in the accuracy of precipitation and other meteorological variables simulated by atmospheric models, and (b) the problem of discordant scales between atmospheric and bydrological models. Alternative methodologies being developed to address these issues are reviewed.

  12. Some effects of ablation on transport properties in the Jovian atmosphere

    Science.gov (United States)

    Biolsi, L.

    1978-01-01

    In this paper the transport properties at the inner and outer boundary for mixing between ablation products and a Jovian-like atmosphere are calculated. The dominant species at these boundaries are C, H, O, He, H+, and e. Accurate potential energy curves are obtained for the fifteen possible two-body interactions among these species by fitting good semiempirical potentials for which transport collision cross sections have been tabulated to accurate experimental and theoretical information. Results are obtained for the viscosity and translational thermal conductivity of the pure species and the binary diffusion coefficients from 1000 K to 25,000 K. In addition, the mixture translational thermal conductivity and viscosity are calculated at the inner and outer mixing boundaries. This information is required for calculating flowfield properties and surface heating. The most important conclusion is that the translational thermal conductivity is substantially lower at the inner mixing boundary than it is at the outer mixing boundary.

  13. Life cycle water use of low-carbon transport fuels

    International Nuclear Information System (INIS)

    In society's quest to mitigate climate change it is important to consider potential trade-offs in climate solutions impacting other environmental issues. This analysis explores the life cycle water consumption of alternative low-carbon energy sources for transportation. Energy sources analyzed include both biofuels used in internal combustion engines and low-carbon electricity generation methods used in conjunction with electric vehicles. Biofuels considered are corn-based ethanol, soybean biodiesel, cellulosic ethanol from switchgrass, and microbial biodiesel. Electricity sources analyzed are coal with carbon sequestration, photovoltaic cells, and solar concentrators. The assessment method used is hybrid life cycle assessment (LCA), which combines materials-based process method and the economic input-output (EIO) method. To compare these technologies on an even footing the life cycle water use to propel a passenger vehicle one mile is estimated. All technologies evaluated showed an increase in water consumption compared to unleaded gasoline when water use from vehicle manufacturing was included. Scale-up calculations showed that mass adoption of electric vehicles and some configurations of algae and switchgrass systems could potentially contribute to the decarbonization of transportation with tolerable increases in overall water consumption. Irrigated crop based biofuels however were found to have significant potential impact on water resources when scaled up to macroscopic production levels. (author)

  14. Life cycle water use of low-carbon transport fuels

    International Nuclear Information System (INIS)

    In society's quest to mitigate climate change it is important to consider potential trade-offs in climate solutions impacting other environmental issues. This analysis explores the life cycle water consumption of alternative low-carbon energy sources for transportation. Energy sources analyzed include both biofuels used in internal combustion engines and low-carbon electricity generation methods used in conjunction with electric vehicles. Biofuels considered are corn-based ethanol, soybean biodiesel, cellulosic ethanol from switchgrass, and microbial biodiesel. Electricity sources analyzed are coal with carbon sequestration, photovoltaic cells, and solar concentrators. The assessment method used is hybrid life cycle assessment (LCA), which combines materials-based process method and the economic input-output (EIO) method. To compare these technologies on an even footing the life cycle water use to propel a passenger vehicle one mile is estimated. All technologies evaluated showed an increase in water consumption compared to unleaded gasoline when water use from vehicle manufacturing was included. Scale-up calculations showed that mass adoption of electric vehicles and some configurations of algae and switchgrass systems could potentially contribute to the decarbonization of transportation with tolerable increases in overall water consumption. Irrigated crop based biofuels however were found to have significant potential impact on water resources when scaled up to macroscopic production levels.

  15. Water cycle dynamic increases resilience of vegetation under higher atmospheric carbon dioxide concentration

    Science.gov (United States)

    Lemordant, L. A.; Gentine, P.; Stéfanon, M.; Drobinski, P. J.; Fatichi, S.

    2015-12-01

    Plant stomata couple the energy, water and carbon cycles. Photosynthesis requires stomata to open to take up carbon dioxide. In the process water vapor is released as transpiration. As atmospheric CO2 concentration rises, for the same amount of CO2 uptake, less water vapor is transpired, translating into higher water use efficiency. Reduced water vapor losses will increase soil water storage if the leaf area coverage remains similar. This will in turn alter the surface energy partitioning: more heat will be dissipated as sensible heat flux, resulting in possibly higher surface temperatures. In contrast with this common hypothesis, our study shows that the water saved during the growing season by increased WUE can be mobilized by the vegetation and help reduce the maximum temperature of mid-latitude heat waves. The large scale meteorological conditions of 2003 are the basis of four regional model simulations coupling an atmospheric model to a surface model. We performed two simulations with respectively 2003 (CTL) and 2100 (FUT) atmospheric CO2 applied to both the atmospheric and surface models. A third (RAD) and a fourth (FER) simulations are run with 2100 CO2 concentration applied to respectively the atmospheric model only and the surface model only. RAD investigates the impact of the radiative forcing, and FER the response to vegetation CO2 fertilization. Our results show that the water saved through higher water use efficiency during the growing season enabled by higher atmospheric carbon dioxide concentrations helps the vegetation to cope during severe heat and dryness conditions in the summer of mid-latitude climate. These results demonstrate that consideration of the vegetation carbon cycle is essential to model the seasonal water cycle dynamic and land-atmosphere interactions, and enhance the accuracy of the model outputs especially for extreme events. They also have important implications for the future of agriculture, water resources management, ecosystems

  16. The Relation Between Atmospheric Humidity and Temperature Trends for Stratospheric Water

    Science.gov (United States)

    Fueglistaler, S.; Liu, Y. S.; Flannaghan, T. J.; Haynes, P. H.; Dee, D. P.; Read, W. J.; Remsberg, E. E.; Thomason, L. W.; Hurst, D. F.; Lanzante, J. R.; Bernath, P. F.

    2013-01-01

    We analyze the relation between atmospheric temperature and water vapor-a fundamental component of the global climate system-for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective-Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual anomalies of the model predictions show periods of fairly regular oscillations, alternating with more quiescent periods and a few large-amplitude oscillations. They all agree well (correlation coefficients 0.9 and larger) with observations for higherfrequency variations (periods up to 2-3 years). Differences between SWV observations, and temperature data, respectively, render analysis of the model minus observation residual difficult. However, we find fairly well-defined periods of drifts in the residuals. For the 1980s, model predictions differ most, and only the calculation with ERA-Interim temperatures is roughly within observational uncertainties. All model predictions show a drying relative to HALOE in the 1990s, followed by a moistening in the early 2000s. Drifts to NOAA-FPH are similar (but stronger), whereas no drift is present against SAGE II. As a result, the model calculations have a less pronounced drop in SWV in 2000 than HALOE. From the mid-2000s onward, models and observations agree reasonably, and some differences can be traced to problems in the temperature data. These results indicate that both SWV and temperature data may still suffer

  17. Effects of Irrigation in India on the Atmospheric Water Budget

    NARCIS (Netherlands)

    Tuinenburg, O.A.; Hutjes, R.W.A.; Stacke, T.; Wiltshire, A.; Lucas-Picher, P.

    2014-01-01

    The effect of large-scale irrigation in India on the moisture budget of the atmosphere was investigated using three regional climate models and one global climate model, all of which performed an irrigated run and a natural run without irrigation. Using a common irrigation map, year-round irrigation

  18. Formation of Organic Molecules and Water in Warm Disk Atmospheres

    CERN Document Server

    Najita, Joan R; Glassgold, Alfred E

    2011-01-01

    Observations from Spitzer and ground-based infrared spectroscopy reveal significant diversity in the molecular emission from the inner few AU of T Tauri disks. We explore theoretically the possible origin of this diversity by expanding on our earlier thermal-chemical model of disk atmospheres. We consider how variations in grain settling, X-ray irradiation, accretion-related mechanical heating, and the oxygen-to-carbon ratio can affect the thermal and chemical properties of the atmosphere at 0.25-40 AU. We find that these model parameters can account for many properties of the detected molecular emission. The column density of the warm (200-2000K) molecular atmosphere is sensitive to grain settling and the efficiency of accretion-related heating, which may account, at least in part, for the large range in molecular emission fluxes that have been observed. The dependence of the atmospheric properties on the model parameters may also help to explain trends that have been reported in the literature between molec...

  19. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    Science.gov (United States)

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi K.

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.

  20. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    CERN Document Server

    Kasting, James F; Kopparapu, Ravi Kumar

    2015-01-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3-D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a 'moist greenhouse' explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing 'inverse' climate calculations to determine habitable zone boundaries using 1-D models.

  1. A simplified method to estimate atmospheric water vapor using MODIS near-infrared data

    Science.gov (United States)

    Wang, Xinming; Gu, Xiaoping; Wu, Zhanping

    2016-03-01

    Atmospheric water vapor plays a significant role in the study of climate change and hydrological cycle processes. In order to acquire the accurate distribution of atmospheric water vapor which is varying with time, location, and altitude, it is necessary to monitor it at high spatial and temporal resolution. Unfortunately, it is difficult to map the spatial distribution of atmospheric water vapor due to the lack of meteorological instrumentation at adequate spatial and temporal observation scales. This paper introduces a simplified method to retrieve Precipitable Water Vapor (PWV) using the ratio of the apparent reflectance values of the 18th and 19th band of Moderate Resolution Imaging Spectroradiometer (MODIS). Compared to the EOS PWV products of the same time and area, the PWV estimated using this simplified method is closer to the radiosonde results which is considered as the true PWV value. Results reveal that this simplified method is applicable over cloud-free atmospheric conditions of the mid-latitude regions.

  2. Model analysis of the effects of atmospheric drivers on storage water use in Scots pine

    Directory of Open Access Journals (Sweden)

    H. Verbeeck

    2007-08-01

    Full Text Available Storage water use is an indirect consequence of the interplay between different meteorological drivers through their effect on water flow and water potential in trees. We studied these microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L. growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow and – storage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May–18 October.

    Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation and vapour pressure deficit (VPD were the main atmospheric drivers of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed. VPD was determined to be one of the main drivers of these differences. During dry atmospheric conditions (high VPD storage water use was reduced. This reduction was higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought. The daily minimum tree water content was lower in periods of high VPD, but the reserves were not completely depleted after the first day of high VPD, due to refilling during the night.

    Nevertheless, the tree water content deficit was a third important factor influencing storage water use. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storage compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water content

  3. Sodium and chloride transport in soft water and hard water acclimated zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Boisen, A M Z; Amstrup, J; Novak, I; Grosell, M

    2003-01-01

    that this is achieved at least in part by a greatly enhanced apparent uptake capacity and affinity for both ions. Zebrafish maintain plasma and whole body electrolyte concentrations similar to most other freshwater teleosts even in deionized water containing only 35 microM NaCl, i.e soft water. We...... recorded an extremely low transport affinity constant (K(m)) of 8+/-1 microM for the active uptake of Cl(-) in soft water acclimated fish, while other transport kinetic parameters were in agreement with reports for other freshwater organisms. While both Na(+) and Cl(-) uptake in soft water clearly depends...... on apical proton pump activity, changes in abundance and possibly localization of this protein did not appear to contribute to soft water acclimation. Active Cl(-) uptake was strongly dependent on branchial carbonic anhydrase (CA) activity regardless of water type, while the response of Na...

  4. Inter-annual variability in the interhemispheric atmospheric CO2 gradient: contributions from transport and the seasonal rectifier

    International Nuclear Information System (INIS)

    The observed interhemispheric gradient in atmospheric carbon dioxide (CO2) indicates the distribution of CO2 sources and sinks, and for recent decades is evidence of a Northern mid-latitudes sink, a tropical source and southern hemisphere sink. As such, the variability in the gradient also reflects how these fluxes vary with time. However, the variability in the gradient is sensitive to the network of stations used to calculate the gradient. Also, an important consideration when dealing with variability in atmospheric measurements is the contribution due to the variability in the atmospheric transport. Most previous studies have ignored transport variability. Using an atmospheric tracer transport model driven with analysed circulation products, we demonstrate here that the interannual variability in the interhemispheric gradient due to transport alone is significant when compared with the observations. Model experiments show that interannually varying transport combined with both cyclostationary terrestrial biosphere fluxes and time-constant fossil CO2 fluxes generates significant interannual variability, but that the component due to the interannually varying transport and the ocean CO2 fluxes is small. The key contributor to the transport generated interannual variability is due to the variability in the seasonal rectifier (the covariance between the seasonality in the terrestrial biosphere fluxes and atmospheric transport, which results in non-zero surface CO2 concentrations despite the fluxes balancing at each grid-point). This study shows that the rectifier variability is complex, with different regions displaying different modes of variability. We also investigate the role of the Pearman Pump (gradient due to the seasonal covariance in the fluxes and cross-hemispheric transport) and show that while it appears to be a process occurring in the atmosphere, it is of second-order importance in forcing the interhemispheric gradient

  5. Modelling strategies of the soil plant atmosphere continuum in water limited environments and elevated atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Higher temperatures and changes in rainfall patterns have been forecasted for the future because of higher levels of carbon dioxide in the atmosphere. Warmer temperatures may cause an increase in evapotranspiration (ET) demand. A reduction in rainfall could heighten the severity and duration of drought in arid and semi-arid regions. This paper presented the water transfer scheme which includes water uptake by roots. It also described the interaction between ET and carbon dioxide enrichment. The predicted response of a plant canopy in relation to energy exchange processes was also tested for elevated atmospheric carbon dioxide level. Simulated and measured canopy conductances were reduced by about 30 per cent under elevated carbon dioxide under ideal water supply conditions. A 6 per cent reduction in both simulated and measured seasonal water use was observed under ideal conditions, while a 2 per cent reduction was observed under suboptimum irrigation. The modelling framework also included adaptation and functioning of root system of woody plant canopies. The hypothesis that water that has been relocated via hydraulic lift prevents the upper soil layers from becoming extremely dry was confirmed. Soil layers close to the surface were found to maintain soil water potential between -1.0 and -1.3 MPs during the drought period as well as under 2 different rainfall regimes. In contrast, the absence of hydraulic lift caused the soil layer close to the surface to drop to -20 MPa and -28 MPa. An additional amount of water for plant transpiration was not provided in any large amounts when water was relocated via hydraulic lift. It was concluded that carbon dioxide modelling and transpiration interactions may produce accurate estimates of canopy water use under the predicted climate change. Hydraulic lift was found to be more important for redistribution of soil moisture than for canopy transpiration

  6. Atmospheric water balance over oceanic regions as estimated from satellite, merged, and reanalysis data

    Science.gov (United States)

    Park, Hyo-Jin; Shin, Dong-Bin; Yoo, Jung-Moon

    2013-05-01

    The column integrated atmospheric water balance over the ocean was examined using satellite-based and merged data sets for the period from 2000 to 2005. The data sets for the components of the atmospheric water balance include evaporation from the HOAPS, GSSTF, and OAFlux and precipitation from the HOAPS, CMAP, and GPCP. The water vapor tendency was derived from water vapor data of HOAPS. The product for water vapor flux convergence estimated using satellite observation data was used. The atmospheric balance components from the MERRA reanalysis data were also examined. Residuals of the atmospheric water balance equation were estimated using nine possible combinations of the data sets over the ocean between 60°N and 60°S. The results showed that there was considerable disagreement in the residual intensities and distributions from the different combinations of the data sets. In particular, the residuals in the estimations of the satellite-based atmospheric budget appear to be large over the oceanic areas with heavy precipitation such as the intertropical convergence zone, South Pacific convergence zone, and monsoon regions. The lack of closure of the atmospheric water cycle may be attributed to the uncertainties in the data sets and approximations in the atmospheric water balance equation. Meanwhile, the anomalies of the residuals from the nine combinations of the data sets are in good agreement with their variability patterns. These results suggest that significant consideration is needed when applying the data sets of water budget components to quantitative water budget studies, while climate variability analysis based on the residuals may produce similar results.

  7. Computational benchmarking of fast neutron transport throughout large water thicknesses

    International Nuclear Information System (INIS)

    Neutron dosimetry experiments seem to point our difficulties in the treatment of large water thickness like those encountered between the core baffle and the pressure vessel. This paper describes the theoretical benchmark undertaken by EDF, SCK/CEN and TRACTEBEL ENERGY ENGINEERING, concerning the transport of fast neutrons throughout a one meter cube of water, located after a U-235 fission sources plate. The results showed no major discrepancies between the calculations up to 50 cm from the source, accepting that a P3 development of the Legendre polynomials is necessary for the Sn calculations. The main differences occurred after 50 cm, reaching 20 % at the end of the water cube. This results lead us to consider an experimental benchmark, dedicated to the problem of fast neutron deep penetration in water, which has been launched at SCK/CEN. (authors)

  8. 3D Water Vapor Field in the Atmospheric Boundary Layer Observed with Scanning Differential Absorption Lidar

    OpenAIRE

    Späth, F.; A. Behrendt; Muppa, S. K.; S. Metzendorf; A. Riede; V. Wulfmeyer

    2016-01-01

    The scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) determines fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and spatial resolution of up to a few tens of meters. We present three case studies which show that this high resolution combined with 2- and 3-dimensional scans allows for new insights in the 3-dimensional structure of the water vapor field in the atmospheric boundary layer (ABL). In spring 2013, th...

  9. Strengthening of the hydrological cycle in future scenarios: atmospheric energy and water balance perspective

    OpenAIRE

    A. Alessandri; Fogli, P. G.; Vichi, M.; Zeng, N.

    2012-01-01

    Future climate scenarios experiencing global warming are expected to strengthen hydrological cycle during 21st century by comparison with the last decades of 20th century. We analyze strengthening of the global-scale increase in precipitation from the perspective of changes in whole atmospheric water and energy balances. Furthermore, by combining energy and water equations for the whole atmosphere we profitably obtain constraints for the changes in surface fluxes and for the partitioning at t...

  10. Atmospheric and Surface Contributions to Planetary Albedo and their Relationship to the Total Meridional Energy Transport

    Science.gov (United States)

    Donohoe, A.; Battisti, D. S.

    2010-12-01

    The meridional distribution of incident solar radiation and planetary albedo both contribute to the equator-to-pole gradient in absorbed solar radiation (ASR) in the observed climate system. While the former component is determined by the Earth-Sun geometry and composes 60% of the equator-to-pole gradient in ASR, the latter component makes a significant (40%) contribution to the ASR gradient and is potentially a function of climate state due to its dependence on both atmospheric and surface albedo. In turn, the equator-to-pole gradient in planetary albedo is found to be primarily (86% -89%) dictated by atmospheric albedo with meridional gradients in surface albedo playing a much smaller role in forcing the climate system on the equator-to-pole scale. Simulations of the pre-industrial climate system using the CMIP3 coupled models show large differences in the equator-to-pole gradient in planetary albedo which are mainly due to differences in the simulated cloud distribution, with surface processes playing a much smaller role. The inter-model spread in total meridional heat transport is also primarily (85% of the inter-model spread) due to differences in the simulated cloud distribution. Further model simulations demonstrate that the surface albedo changes associated with moving from the present climate to an ice free climate have a small effect on the equator-to-pole gradient of ASR as compared to the uncertainty in simulated cloud distributions, and hence a small effect on the meridional heat transport.

  11. Pollutants transport and atmospheric variability of CO2 over Siberia: contribution of airborne measurements

    International Nuclear Information System (INIS)

    The work presented here intends to characterize the variations of atmospheric concentrations of CO2, CO, O3 and ultrafine particles, over a large scale aircraft transect above Siberia, during three intensive YAK-AEROSIB campaigns in April 2006, September 2006 and August 2007, respectively. Pollutant and greenhouse gases distribution in this poorly studied region is needed to model atmospheric long range transport. I show here that CO concentrations at the time of the campaigns is broadly affected by (1) advection of Chinese pollutants through baro-clinic perturbations, (2) advection (diffuse or not) of European pollutants at various altitudes, (3) and of biomass burning from Central Asia. This set of factors is analyzed through a novel statistical technique based on clustering of backward transport simulated by the FLEXPART Lagrangian model. Large observed CO2 gradients in summer are matched against vertical mixing in GCM simulated CO2. At last I present ultrafine particle measurements, and a possible nucleation summer maximum in the clean, continental mid-troposphere. (author)

  12. Semi-volatile organic compounds as molecular markers for atmospheric and ecosystem transport

    Science.gov (United States)

    Genualdi, Susan

    The use of semi-volatile organic compounds (SOCs) as molecular markers to identify the contributions of regional and long-range atmospheric transport, as well as current and historic sources, and contaminant deposition in remote ecosystems of the Western U.S. was investigated. Trans-Pacific air masses influenced by Siberian biomass burning events had elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and the historic use pesticides dieldrin and alpha-HCH, while air masses influenced by regional fires in the Pacific Northwestern U.S. had enhanced concentrations of PAHs and the current-use pesticides dacthal and endosulfan. This suggests that previously deposited SOCs, such as pesticides, revolatilize to the atmosphere during forest fires. In addition, forest soils collected from a burned area in the Pacific Northwestern U.S. had significantly lower SOC concentrations (34 to 100 %) than soils collected from an unburned area separated only by a two lane road. This confirms that SOCs re-volatilize and/or degrade from soils and vegetation during the burning process. The chiral signatures of alpha-HCH in air masses at three sites in the Pacific Northwestern U.S. indicated that the boundary layer has a non-racemic alpha-HCH signature likely due to re-volatilization of alpha-HCH from the Pacific Ocean and that the free troposphere is a source of racemic alpha-HCH. Racemic alpha-HCH was also associated with Asian and trans-Pacific air masses. Racemic cis and trans-chlordane in Pacific Northwestern U.S. air masses indicated that U.S. urban areas continue to be a source of chlordane to the atmosphere. The deposition of non-racemic alpha-HCH in seasonal snowpack in continental Western U.S. national park high elevation ecosystems reflected regional transport, while the high latitude, Alaskan national parks were influenced by long-range atmospheric transport of racemic alpha-HCH. The chiral signature of alpha-HCH in fish collected from high elevation and high

  13. Strain Engineering Water Transport in Graphene Nano-channels

    OpenAIRE

    Xiong, Wei; Liu, Jefferson Zhe; Ma, Ming; Xu, Zhiping; Sheridan, John; Zheng, Quanshui

    2011-01-01

    Using equilibrium and non-equilibrium molecular dynamic (MD) simulations, we found that engineering the strain on the graphene planes forming a channel can drastically change the interfacial friction of water transport through it. There is a sixfold change of interfacial friction stress when the strain changes from -10% to 10%. Stretching the graphene walls increases the interfacial shear stress, while compressing the graphene walls reduces it. Detailed analysis of the molecular structure rev...

  14. Co-regulation of water and K(+) transport in sunflower plants during water stress recovery.

    Science.gov (United States)

    Benlloch, Manuel; Benlloch-González, María

    2016-06-01

    16-day-old sunflower (Helianthus annuus L.) plants were subjected to deficit irrigation for 12 days. Following this period, plants were rehydrated for 2 days to study plant responses to post-stress recovery. The moderate water stress treatment applied reduced growth in all plant organs and the accumulation of K(+) in the shoot. After the rehydration period, the stem recovered its growth and reached a similar length to the control, an effect which was not observed in either root or leaves. Moreover, plant rehydration after water stress favored the accumulation of K(+) in the apical zone of the stem and expanding leaves. In the roots of plants under water stress, watering to field capacity, once the plants were de- topped, rapidly favored K(+) and water transport in the excised roots. This quick and short-lived response was not observed in roots of plants recovered from water stress for 2 days. These results suggest that the recovery of plant growth after water stress is related to coordinated water and K(+) transport from the root to the apical zone of the ​​stem and expanding leaves. This stimulation of K(+) transport in the root and its accumulation in the cells of the growing zones of the ​​stem must be one of the first responses induced in the plant during water stress recovery. PMID:27016874

  15. Heat and water transfer in bare topsoil and the lower atmosphere

    OpenAIRE

    ten Berge, H.F.M.

    1996-01-01

    This book describes an analysis of processes and factors that affect the energy balance of bare soil, and the associated exchange of heat and moisture at the surface. After a brief treatment of basic transport theory, the processes of soil-atmosphere interaction are expressed in a simulation algorithm. This algorithm provides an instrument to study the 'conditioning' effect of soil on the lower atmosphere, and vice versa. Examples of sensitivity analysis are presented, with emphasis on the be...

  16. Study of interfacial area transport and sensitivity analysis for air-water bubbly flow

    International Nuclear Information System (INIS)

    The interfacial area transport equation applicable to the bubbly flow is presented. The model is evaluated against the data acquired by the state-of-the-art miniaturized double-sensor conductivity probe in an adiabatic air-water co-current vertical test loop under atmospheric pressure condition. In general, a good agreement, within the measurement error of plus/minus 10%, is observed for a wide range in the bubbly flow regime. The sensitivity analysis on the individual particle interaction mechanisms demonstrates the active interactions between the bubbles and highlights the mechanisms playing the dominant role in interfacial area transport. The analysis employing the drift flux model is also performed for the data acquired. Under the given flow conditions, the distribution parameter of 1.076 yields the best fit to the data

  17. Study of interfacial area transport and sensitivity analysis for air-water bubbly flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Sun, X.; Ishii, M.; Beus, S.G.

    2000-09-01

    The interfacial area transport equation applicable to the bubbly flow is presented. The model is evaluated against the data acquired by the state-of-the-art miniaturized double-sensor conductivity probe in an adiabatic air-water co-current vertical test loop under atmospheric pressure condition. In general, a good agreement, within the measurement error of plus/minus 10%, is observed for a wide range in the bubbly flow regime. The sensitivity analysis on the individual particle interaction mechanisms demonstrates the active interactions between the bubbles and highlights the mechanisms playing the dominant role in interfacial area transport. The analysis employing the drift flux model is also performed for the data acquired. Under the given flow conditions, the distribution parameter of 1.076 yields the best fit to the data.

  18. The role of atmospheric heat transport in the seasonal carbon dioxide cycle

    Science.gov (United States)

    Pollack, James B.; Haberle, R. M.; Murphy, James R.; Schaeffer, J.

    1993-01-01

    We have carried out numerical experiments with a general circulations model (GCM) and energy balance model of the martian atmosphere to define the importance of heat transported to the polar regions in determining the amount of CO2 condensed on the surface during the fall and winter seasons and the amount sublimated during the spring and summer seasons. In so doing, we performed both sensitivity experiments, in which the dust opacity was varied over the full range of its observed values, and annual simulations, in which the dust opacity varied continuously with seasonal data, in accord with measurements taken at the Viking landers. Dust opacity represents the key variable for determining the contribution of atmospheric heat advection to the energy budget in the polar regions. The amount of heat advected to the winter polar regions increases monotonically as the dust opacity at low and middle latitudes increases. However, the increase is sharpest between optical depths of 0 and 1 tends to level off at still higher optical depths. Heat advection is more important at times of CO2 condensation than CO2 sublimation, since the temperature gradients are much steeper in the winter hemisphere than in the summer hemisphere. Because dust opacity is much higher during northern winter than during southern winter, atmospheric heat advection reduces the amount of CO2 that condenses in the north by a much larger factor than it does in the south.

  19. A regional study of atmospheric gravity waves using the USArray Transportable Array

    Science.gov (United States)

    Hedlin, M. A. H.; Stephan, C. C.; de Groot-Hedlin, C. D.; Alexander, M. J.; Hoffmann, L.

    2015-12-01

    The USArray Transportable Array (TA) is a network of approximately 400 seismo-acoustic stations deployed on a 70 km Cartesian grid covering an area of 2,000,000 km2 in the continental United States. The network moves eastward through station redeployments and is now located on the Atlantic coast. This dense network has provided unprecedented opportunities for research in seismology, infrasound and atmospheric science. We have developed a novel technique to investigate gravity wave occurrence and propagation across the network and have applied it to atmospheric pressure data recorded from Jan 1, 2010 through 2014. We divided the stations in this time range into 3,600 non-overlapping triangular arrays (triads). Each triad is most sensitive to propagating gravity waves in the 1-6 hour period range. We report two lines of research with this new dataset. First, we study individual large events in which atmospheric gravity waves are observed to cross the TA. We also study the long-term occurrence statistics of gravity waves and compare them to satellite observations of convective clouds and gravity waves in the stratosphere. We discuss plans for future work when the network is redeployed in Alaska.

  20. The Premar Code for the Monte Carlo Simulation of Radiation Transport In the Atmosphere

    International Nuclear Information System (INIS)

    The Montecarlo code PREMAR is described, which allows the user to simulate the radiation transport in the atmosphere, in the ultraviolet-infrared frequency interval. A plan multilayer geometry is at present foreseen by the code, witch albedo possibility at the lower boundary surface. For a given monochromatic point source, the main quantities computed by the code are the absorption spatial distributions of aerosol and molecules, together with the related atmospheric transmittances. Moreover, simulation of of Lidar experiments are foreseen by the code, the source and telescope fields of view being assigned. To build-up the appropriate probability distributions, an input data library is assumed to be read by the code. For this purpose the radiance-transmittance LOWTRAN-7 code has been conveniently adapted as a source of the library so as to exploit the richness of information of the code for a large variety of atmospheric simulations. Results of applications of the PREMAR code are finally presented, with special reference to simulations of Lidar system and radiometer experiments carried out at the Brasimone ENEA Centre by the Environment Department

  1. A study of atmospheric diffusion from the LANDSAT imagery. [pollution transport over the ocean

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Viswanadham, Y.; Torsani, J. A.

    1981-01-01

    LANDSAT multispectral scanner data of the smoke plumes which originated in eastern Cabo Frio, Brazil and crossed over into the Atlantic Ocean, are analyzed to illustrate how high resolution LANDSAT imagery can aid meteorologists in evaluating specific air pollution events. The eleven LANDSAT images selected are for different months and years. The results show that diffusion is governed primarily by water and air temperature differences. With colder water, low level air is very stable and the vertical diffusion is minimal; but water warmer than the air induces vigorous diffusion. The applicability of three empirical methods for determining the horizontal eddy diffusivity coefficient in the Gaussian plume formula was evaluated with the estimated standard deviation of the crosswind distribution of material in the plume from the LANDSAT imagery. The vertical diffusion coefficient in stable conditions is estimated using Weinstock's formulation. These results form a data base for use in the development and validation of meso scale atmospheric diffusion models.

  2. Influence of model resolution on the atmospheric transport of 10Be

    Directory of Open Access Journals (Sweden)

    A. M. Smith

    2012-11-01

    Full Text Available Understanding the transport path of the solar activity proxy 10Be from source to archive is crucial for the interpretation of its observed variability. The extent of mixing of the strong production signal has been quantified in a previous study (Heikkilä et al., 2009. In this study we perform sensitivity studies to investigate the influence of model resolution on the degree of mixing and transport path of 10Be in the atmosphere using the ECHAM5-HAM aerosol-climate model. This study permits us to choose an acceptable resolution, and so minimum CPU time, to produce reconstructions as physically accurate as possible. Five model resolutions are applied: T21L19: a coarse horizontal and vertical resolution with model top at ca. 30 km, T42L31: an average horizontal and fine vertical one, T42L39: similar vertical resolution than L19 but including the middle atmosphere up to ca. 80 km, T63L31: a fine horizontal and vertical resolution and T63L47: a fine resolution horizontally and vertically with middle atmosphere. Comparison with observations suggests that a finer horizontal and vertical resolution might be beneficial, producing a reduced meridional gradient, although the spread between observations was much larger than between the five model runs. In terms of atmospheric mixing the differences became more distinguishable. All resolutions agreed that the main driver of deposition variability, observed in natural archives, is the input of stratospheric 10Be (total contribution 68% which is transported into the troposphere at latitudes 30–50°. In the troposphere the model resolutions deviated largely in the dispersion of the stratospheric component over latitude. The finest resolution (T63L47 predicted the least dispersion towards low latitudes but the most towards the poles, whereas the coarsest resolution (T21L19 suggested the opposite. The tropospheric components of 10Be differed less between the five model runs. The largest differences were found

  3. Melt onset over Arctic sea ice controlled by atmospheric moisture transport

    Science.gov (United States)

    Mortin, Jonas; Svensson, Gunilla; Graversen, Rune G.; Kapsch, Marie-Luise; Stroeve, Julienne C.; Boisvert, Linette N.

    2016-06-01

    The timing of melt onset affects the surface energy uptake throughout the melt season. Yet the processes triggering melt and causing its large interannual variability are not well understood. Here we show that melt onset over Arctic sea ice is initiated by positive anomalies of water vapor, clouds, and air temperatures that increase the downwelling longwave radiation (LWD) to the surface. The earlier melt onset occurs; the stronger are these anomalies. Downwelling shortwave radiation (SWD) is smaller than usual at melt onset, indicating that melt is not triggered by SWD. When melt occurs early, an anomalously opaque atmosphere with positive LWD anomalies preconditions the surface for weeks preceding melt. In contrast, when melt begins late, clearer than usual conditions are evident prior to melt. Hence, atmospheric processes are imperative for melt onset. It is also found that spring LWD increased during recent decades, consistent with trends toward an earlier melt onset.

  4. Carbon Dioxide in Exoplanetary Atmospheres: Rarely Dominant Compared to Carbon Monoxide and Water in Hot, Hydrogen-dominated Atmospheres

    Science.gov (United States)

    Heng, Kevin; Lyons, James R.

    2016-02-01

    We present a comprehensive study of the abundance of carbon dioxide in exoplanetary atmospheres in hot, hydrogen-dominated atmospheres. We construct novel analytical models of systems in chemical equilibrium that include carbon monoxide, carbon dioxide, water, methane and acetylene and relate the equilibrium constants of the chemical reactions to temperature and pressure via the tabulated Gibbs free energies. We prove that such chemical systems may be described by a quintic equation for the mixing ratio of methane. By examining the abundances of these molecules across a broad range of temperatures (spanning equilibrium temperatures from 600 to 2500 K), pressures (via temperature-pressure profiles that explore albedo and opacity variations) and carbon-to-oxygen ratios, we conclude that carbon dioxide is subdominant compared to carbon monoxide and water. Atmospheric mixing does not alter this conclusion if carbon dioxide is subdominant everywhere in the atmosphere. Carbon dioxide and carbon monoxide may attain comparable abundances if the metallicity is greatly enhanced, but this property is negated by temperatures above 1000 K. For hydrogen-dominated atmospheres, our generic result has the implication that retrieval studies may wish to set the subdominance of carbon dioxide as a prior of the calculation and not let its abundance completely roam free as a fitting parameter, because it directly affects the inferred value of the carbon-to-oxygen ratio and may produce unphysical conclusions. We discuss the relevance of these implications for the hot Jupiter WASP-12b and suggest that some of the previous results are chemically impossible. The relative abundance of carbon dioxide to acetylene is potentially a sensitive diagnostic of the carbon-to-oxygen ratio.

  5. Water Vapour Absorption in the Clear Atmosphere of an exo-Neptune

    CERN Document Server

    Fraine, Jonathan; Benneke, Björn; Knutson, Heather; Jordán, Andrés; Espinoza, Néstor; Madhusudhan, Nikku; Wilkins, Ashlee; Todorov, Kamen

    2014-01-01

    Transmission spectroscopy to date has detected atomic and molecular absorption in Jupiter-sized exoplanets, but intense efforts to measure molecular absorption in the atmospheres of smaller (Neptune-sized) planets during transits have revealed only featureless spectra. From this it was concluded that the majority of small, warm planets evolve to sustain high mean molecular weights, opaque clouds, or scattering hazes in their atmospheres, obscuring our ability to observe the composition of these atmospheres. Here we report observations of the transmission spectrum of HAT-P-11b (~4 Earth radii) from the optical to the infrared. We detected water vapour absorption at 1.4 micrometre wavelength. The amplitude of the water absorption (approximately 250 parts-per- million) indicates that the planetary atmosphere is predominantly clear down to ~1 mbar, and sufficiently hydrogen-rich to exhibit a large scale height. The spectrum is indicative of a planetary atmosphere with an upper limit of ~700 times the abundance of...

  6. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2001-01-01

    Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

  7. Speciation and transport of radionuclides in ground water

    International Nuclear Information System (INIS)

    Studies of the chemical speciation of a number of radionuclides migrating in a slightly contaminated ground water plume are identifying the most mobile species and providing an opportunity to test and/or validate geochemical models of radionuclide transport in ground waters. Results to date have shown that most of the migrating radionuclides are present in anionic or nonionic forms. These include anionic forms of 55Fe, 60Co, /sup 99m/Tc, 106Ru, 131I, and nonionic forms of 63Ni and 125Sb. Strontium-70 and a small fraction of the mobile 60Co are the only cationic radionuclides which have been detected moving in the ground water plume beyond 30 meters from the source. A comparison of the observed chemical forms with the predicted species calculated from modeling thermodynamic data and ground water chemical parameters has indicated a good agreement for most of the radioelements in the system, including Tc, Np, Cs, Sr, Ce, Ru, Sb, Zn, and Mn. The discrepancies between observed and calculated solutions species were noted for Fe, Co, Ni and I. Traces of Fe, Co, and Ni were observed to migrate in anionic or nonionic forms which the calculations failed to predict. These anionic/nonionic species may be organic complexes having enhanced mobility in ground waters. The radioiodine, for example, was shown to behave totally as an anion but further investigation revealed that 49-57% of this anionic iodine was organically bound. The ground water and aqueous extracts of trench sediments contain a wide variety of organic compounds, some of which could serve as complexing agents for the radionuclides. These results indicate the need for further research at a variety of field sites in defining precisely the chemical forms of the mobile radionuclide species, and in better understanding the role of dissolved organic materials in ground water transport of radionuclides

  8. An interpretation of some whole plant water transport phenomena.

    Science.gov (United States)

    Fiscus, E L; Klute, A; Kaufmann, M R

    1983-04-01

    A treatment of water flow into and through plants to the evaporating surface of the leaves is presented. The model is driven by evaporation from the cell wall matrix of the leaves. The adsorptive and pressure components of the cell wall matric potential are analyzed and the continuity between the pressure component and the liquid tension in the xylem established. Continuity of these potential components allows linking of a root transport function, driven by the tension in the xylem, to the leaf water potential. The root component of the overall model allows for the solvent-solute interactions characteristic of a membrane-bound system and discussion of the interactions of environmental variables such as root temperature and soil water potentials. A partition function is developed from data in the literature which describes how water absorbed by the plant might be divided between transpiration and leaf growth over a range of leaf water potentials.Relationships between the overall system conductance and the conductance coefficients of the various plant parts (roots, xylem, leaf matrix) are established and the influence of each of these discussed.The whole plant flow model coupled to the partition function is used to simulate several possible relationships between leaf water potential and transpiration rate. The effects of changing some of the partition function coefficients, as well as the root medium water potential on these simulations is illustrated.In addition to the general usefulness of the model and its ability to describe a wide range of situations, we conclude that the relationships used, dealing with bulk fluid flow, diffusion, and solute transport, are adequate to describe the system and that analogically based theoretical systems, such as the Ohm's law analogy, probably ought to be abandoned for this purpose. PMID:16662912

  9. A Plant-Based Proxy for the Oxygen Isotope Ratio of Atmospheric Water Vapor

    Science.gov (United States)

    Helliker, B.

    2007-12-01

    Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. It is shown here that the oxygen isotope ratio of leaf water in the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides (Spanish Moss) is controlled by the oxygen isotope ratio of atmospheric water vapor in both field and lab studies. Assuming that the leaf-water isotopic signature (and hence the atmospheric water vapor signature) is recorded in plant organic material, the atmospheric water vapor oxygen isotope ratios for Miami, Florida (USA) were reconstructed for several years from 1878 to 2005 using contemporary and herbarium specimens. T. usneoides ranges from Virginia, USA southwards through the tropics to Argentina, and the CAM epiphytic lifeform is widespread in other species. Therefore, epiphytes may be used to reconstruct the isotope ratio of atmospheric water for spatial scales that span over 60° of latitude and temporal scales that cover the last century of global temperature increase.

  10. Inferring global and regional methane sources and sinks using isotopic observations and atmospheric chemical transport models

    Science.gov (United States)

    Rigby, M. L.; Wenger, A.; O'Doherty, S.; Lunt, M. F.; Ganesan, A.; Manning, A.; Prinn, R. G.

    2015-12-01

    Measurements of the major isotopologues of atmospheric methane have the potential to improve our understanding of the methane budget at the global and regional scale. Using global and regional chemical transport models, we can predict the atmospheric variations in 13C-CH4 and D-CH4, for given assumptions about source isotope ratios and fractionation due to methane sinks. This information can then be used to test the impact that various measurement techniques, technologies and sampling strategies have on our knowledge of the methane budget. We show that, at the global scale, an extensive and accurate network of isotopic measurements can lead to a reduction in the uncertainties in the major global sources. Furthermore, measurements of the D/H ratio in methane may provide some level of uncertainty reduction in the magnitude of the OH sink. Uncertainties can be reduced with improved precision and accuracy of the atmospheric observations. However, to make the most of an atmospheric methane isotope network, we show that the characterisation of source isotope ratios must also be improved. Finally, we put the theory into practice by deriving sector-specific methane sources at the national scale using 13C-CH4 samples collected as part of the Greenhouse gAs Uk and Global Emissions (GAUGE) project. GAUGE measurements are made from a tall tower site to the east of the UK, a background station on the west coast of Ireland and during intensive aircraft sampling campaigns. We will discuss the challenges and benefits associated with adding isotopic information to a national greenhouse gas sampling network and outline a strategy for improvements in the future.

  11. Study of atmospheric gravity waves and infrasonic sources using the USArray Transportable Array pressure data

    Science.gov (United States)

    Hedlin, Michael; de Groot-Hedlin, Catherine; Hoffmann, Lars; Alexander, M. Joan; Stephan, Claudia

    2016-04-01

    The upgrade of the USArray Transportable Array (TA) with microbarometers and infrasound microphones has created an opportunity for a broad range of new studies of atmospheric sources and the large- and small-scale atmospheric structure through which signals from these events propagate. These studies are akin to early studies of seismic events and the Earth's interior structure that were made possible by the first seismic networks. In one early study with the new dataset we use the method of de Groot-Hedlin and Hedlin (2015) to recast the TA as a massive collection of 3-element arrays to detect and locate large infrasonic events. Over 2,000 events have been detected in 2013. The events cluster in highly active regions on land and offshore. Stratospherically ducted signals from some of these events have been recorded more than 2,000 km from the source and clearly show dispersion due to propagation through atmospheric gravity waves. Modeling of these signals has been used to test statistical models of atmospheric gravity waves. The network is also useful for making direct observations of gravity waves. We are currently studying TA and satellite observations of gravity waves from singular events to better understand how the waves near ground level relate to those observed aloft. We are also studying the long-term statistics of these waves from the beginning of 2010 through 2014. Early work using data bandpass filtered from 1-6 hr shows that both the TA and satellite data reveal highly active source regions, such as near the Great Lakes. de Groot-Hedlin and Hedlin, 2015, A method for detecting and locating geophysical events using clusters of arrays, Geophysical Journal International, v203, p960-971, doi: 10.1093/gji/ggv345.

  12. Absorption of solar radiation by atmospheric water vapour

    International Nuclear Information System (INIS)

    Solar spectra from 0.7 to 2.5 μm were studied under low resolution for different solar zenith angles. The band integrated absorbance for water vapour bands at 0.8, 0.9, 1.1, 1.4 and 1.9 μm were measured and compared with those obtained by Howard et al. and other workers. It was found that although the agreement was satisfactory at lower water-vapour contents, there was significant deviation at high water-vapour content. (author)

  13. Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-26

    Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy. In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240

  14. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    Energy Technology Data Exchange (ETDEWEB)

    Poellaenen, R

    2002-05-01

    In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has

  15. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    International Nuclear Information System (INIS)

    In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has been higher

  16. A Continental Shelf Sediment Transport Proxy Record of Decadal Atmospheric and Oceanographic Variability in Southern Alaska

    Science.gov (United States)

    Vienne, W. F.; Jaeger, J.

    2004-12-01

    The Gulf of Alaska (GOA) margin is a prime location to study and quantitatively model glacial climate and continental margin sedimentation. Coupled oceanographic and atmospheric processes control sediment transport and sedimentation patterns on the GOA continental shelf, and consequently contain a proxy record for regional climate variability. However, the specifics of this coupled relationship between climate and sediment transport have not been studied. In collaboration with the GOA-NEP GLOBEC program, gravity cores were taken at three sites of high sedimentation rates along the GOA margin in 2001 and 2003 representing proximal and distal shelf depocenters. Chronologies were established using Pb-210 and Cs-137 and sedimentation rates vary from 0.3 to 3 cm/yr, providing near-annual to decadal-scale resolution. High-spatial resolution grain-size analyses and multi-sensor core logging of bulk density and magnetic susceptibility were measured to recognize relationships between these three proxies of sediment transport in each core and between sites. The time series of these properties have been compared to oceanographic and atmospheric instrumental records--generally beginning in the early to middle 20th century--such as sea level pressure, temperature, significant wave height, and wind speed. The three measured properties positively correlate within each core and between each core, indicating that these are likely controlled by similar sediment transport processes, such as wave resuspension and bottom-current transport, at all three sites. Strong correlation on a decadal scale was found between the physical properties of the cores and the instrumental records of temperature and significant wave height, as well as variability in regional precipitation. Also, there is a marked increase in bulk density, magnetic susceptibility, and grain size values from the late 1970's onward, which corresponds to the timing of a shift from a negative to a positive regime in the

  17. Assessment and Requirements of Nuclear Reaction Databases for GCR Transport in the Atmosphere and Structures

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Shinn, J. L.; Tripathi, R. K.

    1998-01-01

    The transport properties of galactic cosmic rays (GCR) in the atmosphere, material structures, and human body (self-shielding) am of interest in risk assessment for supersonic and subsonic aircraft and for space travel in low-Earth orbit and on interplanetary missions. Nuclear reactions, such as knockout and fragmentation, present large modifications of particle type and energies of the galactic cosmic rays in penetrating materials. We make an assessment of the current nuclear reaction models and improvements in these model for developing required transport code data bases. A new fragmentation data base (QMSFRG) based on microscopic models is compared to the NUCFRG2 model and implications for shield assessment made using the HZETRN radiation transport code. For deep penetration problems, the build-up of light particles, such as nucleons, light clusters and mesons from nuclear reactions in conjunction with the absorption of the heavy ions, leads to the dominance of the charge Z = 0, 1, and 2 hadrons in the exposures at large penetration depths. Light particles are produced through nuclear or cluster knockout and in evaporation events with characteristically distinct spectra which play unique roles in the build-up of secondary radiation's in shielding. We describe models of light particle production in nucleon and heavy ion induced reactions and make an assessment of the importance of light particle multiplicity and spectral parameters in these exposures.

  18. Load of soil and water by atmospheric nitrogen deposition

    International Nuclear Information System (INIS)

    After comprehensive retrofitting of power plants with flue gas desulfurization systems has been completed in Germany, nitrogen oxides (NOx) and ammonia became the most important air pollutants. Pollution control measures to reduce the release of these substances which predominantly originate from traffic and agriculture had only marginal success. Some way or other, emissions into the atmosphere return to the ground and entail here generally harmful side effects. After introductory remarks on nitrogen as an air contaminant, the present potential in the derivation of emittor/receptor-relationships for nitrogen compounds are described. Subsequently, the nitrogen deposition rates are quantified and evaluated. (orig.)

  19. Hybrid advection scheme for 3-dimensional atmospheric models. Testing and application for a study of NO{sub x} transport

    Energy Technology Data Exchange (ETDEWEB)

    Zubov, V.A.; Rozanov, E.V. [Main Geophysical Observatory, St.Petersburg (Russian Federation); Schlesinger, M.E.; Andronova, N.G. [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Atmospheric Sciences

    1997-12-31

    The problems of ozone depletion, climate change and atmospheric pollution strongly depend on the processes of production, destruction and transport of chemical species. A hybrid transport scheme was developed, consisting of the semi-Lagrangian scheme for horizontal advection and the Prather scheme for vertical transport, which have been used for the Atmospheric Chemical Transport model to calculate the distributions of different chemical species. The performance of the new hybrid scheme has been evaluated in comparison with other transport schemes on the basis of specially designed tests. The seasonal cycle of the distribution of N{sub 2}O simulated by the model, as well as the dispersion of NO{sub x} exhausted from subsonic aircraft, are in a good agreement with published data. (author) 8 refs.

  20. The potential for regional-scale bias in top-down CO2 flux estimates due to atmospheric transport errors

    Directory of Open Access Journals (Sweden)

    S. M. Miller

    2014-09-01

    Full Text Available Estimates of CO2 fluxes that are based on atmospheric data rely upon a meteorological model to simulate atmospheric CO2 transport. These models provide a quantitative link between surface fluxes of CO2 and atmospheric measurements taken downwind. Therefore, any errors in the meteorological model can propagate into atmospheric CO2 transport and ultimately bias the estimated CO2 fluxes. These errors, however, have traditionally been difficult to characterize. To examine the effects of CO2 transport errors on estimated CO2 fluxes, we use a global meteorological model-data assimilation system known as "CAM–LETKF" to quantify two aspects of the transport errors: error variances (standard deviations and temporal error correlations. Furthermore, we develop two case studies. In the first case study, we examine the extent to which CO2 transport uncertainties can bias CO2 flux estimates. In particular, we use a common flux estimate known as CarbonTracker to discover the minimum hypothetical bias that can be detected above the CO2 transport uncertainties. In the second case study, we then investigate which meteorological conditions may contribute to month-long biases in modeled atmospheric transport. We estimate 6 hourly CO2 transport uncertainties in the model surface layer that range from 0.15 to 9.6 ppm (standard deviation, depending on location, and we estimate an average error decorrelation time of ∼2.3 days at existing CO2 observation sites. As a consequence of these uncertainties, we find that CarbonTracker CO2 fluxes would need to be biased by at least 29%, on average, before that bias were detectable at existing non-marine atmospheric CO2 observation sites. Furthermore, we find that persistent, bias-type errors in atmospheric transport are associated with consistent low net radiation, low energy boundary layer conditions. The meteorological model is not necessarily more uncertain in these conditions. Rather, the extent to which meteorological

  1. A new look at the atmospheric water cycle: measurements of water vapor and its main isotopologue using SCIAMACHY

    Science.gov (United States)

    Scheepmaker, Remco; Frankenberg, Christian; Aben, Ilse; Schrijver, Hans; Gloudemans, Annemieke; Roeckmann, Thomas; Yoshimura, Kei

    2010-05-01

    Water vapor is by far the most important greenhouse gas in the atmosphere. As a warmer atmosphere can contain more water vapor, a positive feedback effect with respect to climate change is expected. The distribution of water vapor is very inhomogeneous and variable, unlike that of other greenhouse gases. In the light of climate reconstructions and predictions, it is therefore crucial to better understand the water cycle and its response to past and present climate change. The relative abundance of the heavy water isotopologue HDO provides a deeper insight in the water cycle, as evaporation and condensation processes deplete heavy water in the gas phase. In the application of isotopologues, however, the space-borne retrieval of atmospheric water vapor isotopologues near the surface has so far been overlooked. We provide, for the first time (Frankenberg et al., Science 2009), global HDO/H2O abundances using the Scanning Imaging Absorption spectroMeter for Atmospheric CHartography (SCIAMACHY) instrument onboard ENVISAT. This allows for an entirely new perspective on the near-surface distribution of water vapor isotopologues. We are using the 2.3 micron (SWIR) window of SCIAMACHY, which is also used for the first time (Schrijver et al., AMT 2009) to derive total water vapor columns. Because of this wavelength range, and because SCIAMACHY is an absorption spectrometer, we are sensitive down to the lowest parts of the atmosphere where most of the water vapor resides. We further exploit a novel method to correct for the scattering effects of an ice layer on the SWIR detector and in order to further improve the accuracy of our HDO/H2O dataset, we derived an improved spectral linelist for H2O in the 2.3 micron window. The total water vapor columns have been validated with collocated ECMWF data and show good agreement. First results of atmospheric HDO/H2O show an expected latitudinal gradient, but also strong evaporation signals over the Red Sea and highly depleted values

  2. Impact of soil water property parameterization on atmospheric boundary layer simulation

    Science.gov (United States)

    Cuenca, Richard H.; Ek, Michael; Mahrt, Larry

    1996-03-01

    Both the form of functional relationships applied for soil water properties and the natural field-scale variability of such properties can significantly impact simulation of the soil-plant-atmosphere system on a diurnal timescale. Various input parameters for soil water properties including effective saturation, residual water content, anerobiosis point, field capacity, and permanent wilting point are incorporated into functions describing soil water retention, hydraulic conductivity, diffusivity, sorptivity, and the plant sink function. The perception of the meaning of these values and their variation within a natural environment often differs from the perspective of the soil physicist, plant physiologist, and atmospheric scientist. This article investigates the sensitivity of energy balance and boundary layer simulation to different soil water property functions using the Oregon State University coupled atmosphere-plant-soil (CAPS) simulation model under bare soil conditions. The soil parameterizations tested in the CAPS model include those of Clapp and Hornberger [1978], van Genuchten [1980], and Cosby et al. [1984] using initial atmospheric conditions from June 16, 1986 in Hydrologic Atmospheric Pilot Experiment-Modélisation du Bilan Hydrique (HAPEX-MOBILHY). For the bare soil case these results demonstrate unexpected model sensitivity to soil water property parameterization in partitioning all components of the diurnal energy balance and corresponding boundary layer development.

  3. Hydrological model for the transport of radioisotope in surface water

    International Nuclear Information System (INIS)

    The use of radioisotopes has gained grounds in Ghana as a result of the numerous benefits that could be derived from it. In Ghana, radioisotope materials are used for various purposes in a number of institutions. However, improper disposal of the waste poses threat to the environment. To evaluate the environmental impact of radioisotope pollution, mathematical models play a major role in predicting the pollution level in any medium. This study is concerned with the hydrological model for the transport of radioactive material in the river. The model was composed by employing partial differential equations, describing relevant physical processes evolution (water level, velocities and dissolved substances concentrations) that occurs in water bodies. The mass conservation and momentum laws, state equation and state transport equations are equation system basis. The explicit central difference scheme in space and a forward difference method in time were used for the evaluation of the generalized transport equation, the Advection-Dispersion Equation. A Matlab code was developed to predict the concentration of the radioactive contaminant at any particular time along the river and in a reservoir. The model was able to simulate accurately the various levels of radionuclide concentration changes in the flowing rivers as the flows are augmented by tributary inflows. (au)

  4. Reactivity of water vapor in an atmospheric pressure DBD -Application to LDPE surfaces

    CERN Document Server

    Collette, S; Viville, Pascal; Reniers, François

    2016-01-01

    The reactivity of water vapor introduced in an atmospheric dielectric barrier discharge supplied in argon is investigated through optical emission spectroscopy measurements. This discharge is also used for the treatment of LDPE surfaces. Water contact angles measurements, XPS and AFM techniques are used to study the grafting of oxygen functions on the LDPE surface and increase its hydrophilicity.

  5. Water Vapour Content of the Atmosphere in Relation to Surface Humidity

    Directory of Open Access Journals (Sweden)

    N. C. Majumdar

    1977-10-01

    Full Text Available The theoretical relationship between precipitate water vapour in the atmosphere & surface humidity has been investigated. By introducing the concept of a lapse parameter alpha, a method has been devised for estimation of precipitable water vapour. Results have been compared for six Indian Stations for which upper air data were available.

  6. New progress of research on water cycle in atmosphere in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.

  7. Water cycles in closed ecological systems: effects of atmospheric pressure

    Science.gov (United States)

    Rygalov, Vadim Y.; Fowler, Philip A.; Metz, Joannah M.; Wheeler, Raymond M.; Bucklin, Ray A.; Sager, J. C. (Principal Investigator)

    2002-01-01

    In bioregenerative life support systems that use plants to generate food and oxygen, the largest mass flux between the plants and their surrounding environment will be water. This water cycle is a consequence of the continuous change of state (evaporation-condensation) from liquid to gas through the process of transpiration and the need to transfer heat (cool) and dehumidify the plant growth chamber. Evapotranspiration rates for full plant canopies can range from 1 to 10 L m-2 d-1 (1 to 10 mm m-2 d-1), with the rates depending primarily on the vapor pressure deficit (VPD) between the leaves and the air inside the plant growth chamber. VPD in turn is dependent on the air temperature, leaf temperature, and current value of relative humidity (RH). Concepts for developing closed plant growth systems, such as greenhouses for Mars, have been discussed for many years and the feasibility of such systems will depend on the overall system costs and reliability. One approach for reducing system costs would be to reduce the operating pressure within the greenhouse to reduce structural mass and gas leakage. But managing plant growth environments at low pressures (e.g., controlling humidity and heat exchange) may be difficult, and the effects of low-pressure environments on plant growth and system water cycling need further study. We present experimental evidence to show that water saturation pressures in air under isothermal conditions are only slightly affected by total pressure, but the overall water flux from evaporating surfaces can increase as pressure decreases. Mathematical models describing these observations are presented, along with discussion of the importance for considering "water cycles" in closed bioregenerative life support systems.

  8. Unsaturated water flow and tracer transport modeling with Alliances

    International Nuclear Information System (INIS)

    Highlights: • Simulation of water flow and solute transport at Saligny site, Romania was done. • Computation was based on the available experimental data with Alliances platform. • Very good results were obtained for the saturation profile in steady state. • Close fit to experimental data for saturation profile at 3 m in transient state. • Large dispersivity coefficients were fitted to match tracer experiment. - Abstract: Understanding water flow and solute transport in porous media is of central importance in predicting the radionuclide fate in the geological environment, a topic of interest for the performance and safety assessment studies for nuclear waste disposal. However, it is not easy to predict transport properties in real systems because they are geologically heterogeneous from the pore scale upwards. This paper addresses the simulation of water flow and solute transport in the unsaturated zone of the Saligny site, the potential location for the Romanian low and intermediate level waste (LILW) disposal. Computation was based on the current available experimental data for this zone and was performed within Alliances, a software platform initially jointly developed by French organizations CEA, ANDRA and EDF. The output of the model developed was compared with the measured values in terms of saturation profile of the soil for water movement, in both steady and transient state. Very good results were obtained for the saturation profile in steady state and a close fit of the simulation over experimental data for the water saturation profile at a depth of 3 m in transient state. In order to obtain information regarding the solute migration in depth and the solute lateral dispersion, a tracer test was launched on site and dispersivity coefficients of the solute were fitted in order to match the experimental concentration determined on samples from different locations of the site. Results much close to the experiment were obtained for a longitudinal

  9. Numerical Modeling of Water Flow and Salt Transport in Bare Saline Soil Subjected to Transient Evaporation

    Science.gov (United States)

    Geng, X.; Boufadel, M.; Saleh, F. S.

    2014-12-01

    It has been found that evaporation over bare soil plays an important role in subsurface solute transport processes. A numerical study, based on a density-dependent variably saturated groundwater flow model MARUN, was conducted to investigate subsurface flow and salt transport in bare saline aquifers subjected to transient evaporation. The bulk aerodynamic formulation was adopted to simulate transient evaporation rate at ground surface. Subsurface flow pattern, moisture distribution, and salt migration were quantified. Key factors likely affecting this process, including saturated hydraulic conductivity, capillary drive, air humidity, and surrounding water supply, were examined. The results showed that evaporation induced an upward flow pattern, which led to a high saline plume formed beneath the evaporation zone. In absence of surrounding water supply, as the humidity between the ground surface and air tended to equilibrium, evaporation-induced density gradient generated pore water circulations around the plume edge and caused the salt to migrate downwards with "finger" shapes. It was found that capillary properties and atmospheric condition had significant impacts on subsurface moisture distribution and salt migration in response to the evaporation. Larger capillary fringe and/or lower air humidity would allow evaporation to extract more water from the ground. It would induce a larger and denser saline plume formed beneath the evaporation zone. The results also suggested that the presence of the surrounding water supply (represented as a constant water table herein) could provide a steady evaporation rate at the ground surface; meanwhile, in response to the evaporation, a hydraulic gradient was formed from the water supply boundary, which induced an inclined upper saline plume with greater density far from the supply boundary.

  10. Water Transport and the Evolution of CM Parent Bodies

    Science.gov (United States)

    Coker, R.; Cohen, B.

    2014-01-01

    Extraterrestrial water-bearing minerals are of great importance both for understanding the formation and evolution of the solar system and for supporting future human activities in space. Asteroids are the primary source of meteorites, many of which show evidence of an early heating episode and varying degrees of aqueous alteration. The origin and characterization of hydrated minerals (minerals containing H2O or OH) among both the main-belt and near-earth asteroids is important for understanding a wide range of solar system formation and evolutionary processes, as well as for planning for human exploration. Current hypotheses postulate asteroids began as mixtures of water ice and anhydrous silicates. A heating event early in solar system history was then responsible for melting the ice and driving aqueous alteration. The link between asteroids and meteorites is forged by reflectance spectra, which show 3-µm bands indicative of bound OH or H2O on the C-class asteroids, which are believed to be the parent bodies of the carbonaceous chondrites in our collections. The conditions at which aqueous alteration occurred in the parent bodies of carbonaceous chondrites are thought to be well-constrained: at 0-25 C for less than 15 Myr after asteroid formation. In previous models, many scenarios exhibit peak temperatures of the rock and co-existing liquid water in more than 75 percent of the asteroid's volume rising to 150 C and higher, due to the exothermic hydration reactions triggering a thermal runaway effect. However, even in a high porosity, water-saturated asteroid very limited liquid water flow is predicted (distances of 100's nm at most). This contradiction has yet to be resolved. Still, it may be possible for water to become liquid even in the near-surface environment, for a long enough time to drive aqueous alteration before vaporizing or freezing then subliming. Thus, we are using physics- and chemistry-based models that include thermal and fluid transport as well

  11. Investigation of chemical properties and transport phenomena associated with pollutants in the atmospheric boundary layer

    Science.gov (United States)

    Holmes, Heather A.

    Under the Clean Air Act, the U.S. Environmental Protection Agency is required to determine which air pollutants are harmful to human health, then regulate, monitor and establish criteria levels for these pollutants. To accomplish this and for scientific advancement, integration of knowledge from several disciplines is required including: engineering, atmospheric science, chemistry and public health. Recently, a shift has been made to establish interdisciplinary research groups to better understand the atmospheric processes that govern the transport of pollutants and chemical reactions of species in the atmospheric boundary layer (ABL). The primary reason for interdisciplinary collaboration is the need for atmospheric processes to be treated as a coupled system, and to design experiments that measure meteorological, chemical and physical variables simultaneously so forecasting models can be improved (i.e., meteorological and chemical process models). This dissertation focuses on integrating research disciplines to provide a more complete framework to study pollutants in the ABL. For example, chemical characterization of particulate matter (PM) and the physical processes governing PM distribution and mixing are combined to provide more comprehensive data for source apportionment. Data from three field experiments were utilized to study turbulence, meteorological and chemical parameters in the ABL. Two air quality field studies were conducted on the U.S./Mexico border. The first was located in Yuma, AZ to investigate the spatial and temporal variability of PM in an urban environment and relate chemical properties of ambient aerosols to physical findings. The second border air quality study was conducted in Nogales, Sonora, Mexico to investigate the relationship between indoor and outdoor air quality in order to better correlate cooking fuel types and home activities to elevated indoor PM concentrations. The final study was executed in southern Idaho and focused on

  12. Development and Validation of Water Vapor Tracers as Diagnostics for the Atmospheric Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. The formulation of the sources and sinks of tracer water is generally proportional to the prognostic water vapor variable. Because all water has been accounted for in tracers, the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The tracers have been implemented in a GEOS General Circulation Model (GCM) simulation consisting of several summer periods to determine the source regions of precipitation for the United States and India. The recycling of water and interannual variability of the sources of water will be examined. Potential uses in GCM sensitivity studies, predictability studies and data assimilation will be discussed.

  13. A Godunov-Type Scheme for Atmospheric Flows on Unstructured Grids: Scalar Transport

    Science.gov (United States)

    Ahmad, Nash'at; Boybeyi, Zafer; Löhner, Rainald; Sarma, Ananthakrishna

    2006-08-01

    This is the first paper in a two-part series on the implementation of Godunov-type schemes on unstructured grids for atmospheric flow simulations. Construction of a high-resolution flow solver for the scalar transport equation is described in detail. Higher-order accuracy in space is achieved via a MUSCL-type gradient reconstruction after van Leer and the monotonicity of solution is enforced by slope limiters. Accuracy in time is maintained by implementing a multi-stage explicit Runge-Kutta time-marching algorithm. The scheme is conservative and exhibits minimal numerical dispersion and diffusion. Five different benchmark test cases are simulated for the validation of the numerical scheme.

  14. Simulation of transport of atmospheric tracers for decision support system SWD-WJ/RODOS

    International Nuclear Information System (INIS)

    Presented is report on work aimed at implementation computer codes serving for modelling of transport of nuclides and other tracers in the atmosphere. Codes are to be implemented to the decision support system SWD-WJ/RODOS. A comprehensive analysis has been made of different dispersion models from the point of view of their applicability for Polish circumstances, taking into account computer power at Swierk site and goals SWD-WJ/RODOS system is to meet. NPS(LINCOM)/RIMPUFF and HYPACT codes have been presented in more details as those codes have been selected for SWD-WJ/RODOS. Results of computer tests with those codes are presented in the report, in particular results of an international experiment INEX2 performed in November 1998. (author)

  15. Study on radionuclides transport from natural evaporating ponds to the atmosphere

    International Nuclear Information System (INIS)

    The results of simulated experiments, field monitoring and radiation health risk evaluation of radionuclides transport to the atmosphere from the natural evaporating ponds of a certain nuclear factory, and the estimating method of releasing source strength are presented. The estimated results of radiation health risk show that the maximum individual annual risk is 6.5 x 10-9 and the total collective annual risk within a radius of 20 km is 3.2 x 10-5 person, which are caused by operation of the evaporating ponds. It should be pointed out that the above estimated results only refer to one operating year (1990). If the cumulative effect of radionuclides deposition in ground is considered, the risk will increase a little with time until the dynamic balance is achieved. (5 ref., 8 tabs.)

  16. The effects of plants on the transport of methane to the atmosphere from the everglades

    International Nuclear Information System (INIS)

    Comparisons of clipped and unclipped plots showed that the emergent macrophytes, Cladium jamaicense and Eleocharis interstincta, enhanced methane flux to the atmosphere by factors of 1.4 to 3.6. A comparison of night/day methane flux indicated that molecular diffusion, rather that pressurized ventilation, was the dominant gas transport mode in Cladium. Carbon isotopic measurements of sedimentary and emmitted methane indicated that little or no methane oxidation occurred in the rhizosphere of marl soils, as corroborated by incubation data (King et al., Ap. Env. Microb. 56, 2902, 1990). However, isotope data was consistent with the presence of methane oxidation in the rhizosphere of plants living in peat soils as was indicated by the incubation experiment results (Ibid)

  17. Hormonal regulation of ion and water transport in anuran amphibians.

    Science.gov (United States)

    Uchiyama, Minoru; Konno, Norifumi

    2006-05-15

    Amphibians occupy a wide variety of ecological habitats, and their adaptation is made possible through the specialization of the epithelia of their osmoregulatory organs, such as the skin, kidney, and urinary bladder, which control the hydromineral and acid-base balance of their internal medium. Amphibians can change drastically plasma Na+, Cl-, and urea levels and excretion rates in response to environmental stimuli such as acute desiccation and changes in external salinity. Several hormones and the autonomic nervous system act to control osmoregulation. Several ion channels including an epithelial sodium channel (ENaC), a urea transporter (UT), and water channels (AQPs) are found in epithelial tissues of their osmoregulatory organs. This mini review examines the currents status of our knowledge about hormone receptors for arginine vasotocin, angiotensin II and aldosterone, and membrane ion channels and transporters, such as ENaC, UT, and AQPs in amphibians. PMID:16472810

  18. Ion and water transport in charge-modified graphene nanopores

    CERN Document Server

    Qiu, Yinghua; Chen, Weiyu; Si, Wei; Tan, Qiyan; Chen, Yunfei

    2016-01-01

    Porous graphene has high mechanical strength and atomic layer thickness, which make it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solution are a kind of strong long-range interaction which may have great influence on the fluid transport through nanopores. Here, molecular dynamics simulations were conducted to investigate ion and water transport through a 1.05-nm-in-diameter monolayer graphene nanopore with its edge charge-modified. From the results, it is found that the nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase-decrease profile while the co-ion currents monotonously decrease. The co-ions rejection can reach 75% and 90% when the nanopores are negatively and positively charged, respectively. Cl ions current increases and reaches a plateau, and Na+ current decreases with the charge amount in the systems where they act as counterions. Beside...

  19. Fast neutron transport through laminated iron-water shield

    International Nuclear Information System (INIS)

    Reaction rates were measured in a laminated iron-water shield by threshold detectors, from which the neutron spectra were obtained with the aid of the SAND-II code. The error analysis for the unfolding of the spectra proved that the spectra obtained satisfactorily in the energy range of 1 -- 10.5 MeV. One-dimensional calculations were made by the discrete ordinates transport codes ANISN-JR and PALLAS in a spherical geometry. Agreements within a factor of 1.6 for the spectra and 1.31 for the reaction rates were obtained between the measurements and calculations, though rather large discrepancies were found in the spectra at the energy range of 3 -- 7 MeV. All experimental data in absolute value and detailed specifications for source, detector and the experimental geometry are given for a fast neutron transport benchmark calculation. (author)

  20. Micrometeorological Measurement of Fetch- and Atmospheric Stability-Dependent Air- Water Exchange of Legacy Semivolatile Organic Contaminants in Lake Superior

    Science.gov (United States)

    Perlinger, J. A.; Tobias, D. E.; Rowe, M. D.

    2008-12-01

    Coastal waters including the Laurentian Great Lakes are particularly susceptible to local, regional, and long- range transport and deposition of semivolatile organic contaminants (SOCs) as gases and/or associated with particles. Recently-marketed SOCs can be expected to undergo net deposition in surface waters, whereas legacy SOCs such as polychlorinated biphenyls (PCBs) are likely to be at equilibrium with respect to air-water exchange, or, if atmospheric concentrations decrease through, e.g., policy implementation, to undergo net gas emission. SOC air-water exchange flux is usually estimated using the two-film model. This model describes molecular diffusion through the air and water films adjacent to the air-water interface. Air-water exchange flux is estimated as the product of SOC fugacity, typically based on on-shore gaseous concentration measurements, and a transfer coefficient, the latter which is estimated from SOC properties and environmental conditions. The transfer coefficient formulation commonly applied neglects resistance to exchange in the internal boundary layer under atmospherically stable conditions, and the use of on-shore gaseous concentration neglects fetch-dependent equilibration, both of which will tend to cause overestimation of flux magnitude. Thus, for legacy chemicals or in any highly contaminated surface water, the rate at which the water is cleansed through gas emission tends to be over-predicted using this approach. Micrometeorological measurement of air-water exchange rates of legacy SOCs was carried out on ships during four transect experiments during off-shore flow in Lake Superior using novel multicapillary collection devices and thermal extraction technology to measure parts-per-quadrillion SOC levels. Employing sensible heat in the modified Bowen ratio, fluxes at three over-water stations along the transects were measured, along with up-wind, onshore gaseous concentration and aqueous concentration. The atmosphere was unstable for

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

    Directory of Open Access Journals (Sweden)

    M. Righi

    2015-12-01

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

  2. Observations of Fire-Atmosphere Interactions and Near-Surface Heat Transport on a Slope

    Science.gov (United States)

    Clements, Craig B.; Seto, Daisuke

    2015-03-01

    A simple field experiment was conducted to measure and quantify fire-atmosphere interactions during a grass fire spreading up a hill under a moderate cross-slope wind. The observed fire intensity measured by passive radiometers and calculated sensible heat fluxes ranged between 90 and 120 kW m. Observations from this experiment showed that convective heat generated from the fire front was transported downwind in the lowest 2 m and the highest plume temperatures remained in this shallow layer, suggesting the fire spread was driven primarily by the advection of near-ignition temperature gases, rather than by radiation of the tilted flame. Fire-induced circulations were present with upslope flows occurring during the fire-front passage helping to transport heat up the slope and perpendicular to the fire front. A decrease in atmospheric pressure of 0.4 hPa occurred at the fire front and coincided with a strong updraft core of nearly 8 m s. These observations provide evidence that, even under moderately windy conditions, the pressure minimum in the fire remains rather close to the combustion zone and plume. The turbulence associated with the fire front was characterized by isotropic behaviour at 12.0 m above the ground, while less isotropic conditions were found closer to the ground due to higher horizontal variances associated with fire-induced flow at the fire front. From analysis of the turbulence kinetic energy budget terms, it was found that buoyancy production, rather than shear generation, had a larger contribution to the generation of turbulence kinetic energy, even during a highly sheared and moderate ambient wind.

  3. Atmospheric Transport Modelling Activities at CTBTO in the Aftermath of the Fukushima Release

    Science.gov (United States)

    Krysta, M.; Coyne, J.; Nikkinen, M.; Gheddou, A.; Stöhlker, U.

    2012-04-01

    For an accidental radioactive release from the Fukushima nuclear power plant, a spatial location of the source term was known and some reasonable hypotheses were made concerning the time of the emission. Consequently, tests of the performance of an atmospheric transport model operational at CTBTO, FLEXPART, were made. Initially, FLEXPART was run daily in an analysis-forecast mode using NCEP meteorological fields to predict the dates when detections of the radioactive material at the IMS radionuclide stations should be expected. In parallel, ECMWF meteorological analyses were used to drive FLEXPART in a purely diagnostic mode to check for possible better matches between model outputs and radionuclide measurements than those forecast by the NCEP-driven runs. Secondly, once the operational forecasting period at CTBTO came to an end, the ATM activities have been re-focused on the problem of inferring source location from the radionuclide measurements. In addition to radionuclide measurements, a source location algorithm needs outputs of FLEXPART backtracking calculations, Source Receptor Sensitivity (SRS) fields. The SRS fields allow to make a link between radionuclide stations and possible source locations and are computed at CTBTO for each IMS radionuclide station on a daily basis. Various subsets of detections made in the aftermath of the Fukushima release were used to test source location algorithm implemented in our visualisation and analysis software, WEB-Grape. Finally, similar analyses were performed replacing CTBTO SRS fields with the SRS fields provided by the co-operating Regional Specialised Meteorological Centres (RSMCs) of WMO. In fact, the RSMCs support abnormal detections of radionuclides within the IMS network with the SRS calculations performed using their own atmospheric transport models fed with their own meteorological fields. The added value of the SRS fields provided by the RSMCs shall be illustrated.

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

    Science.gov (United States)

    Righi, Mattia; Hendricks, Johannes; Sausen, Robert

    2016-04-01

    We use the EMAC (ECHAM/MESSy Atmospheric Chemistry) global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications) to simulate the impact of aviation emissions on global atmospheric aerosol and climate in 2030. Emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs) designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare our findings with the results of a previous study with the same model configuration focusing on year 2000 emissions. We also characterize the aviation results in the context of the other transport sectors presented in a companion paper. In spite of a relevant increase in aviation traffic volume and resulting emissions of aerosol (black carbon) and aerosol precursor species (nitrogen oxides and sulfur dioxide), the aviation effect on particle mass concentration in 2030 remains quite negligible (on the order of a few ng m-3), about 1 order of magnitude less than the increase in concentration due to other emission sources. Due to the relatively small size of the aviation-induced aerosol, however, the increase in particle number concentration is significant in all scenarios (about 1000 cm-3), mostly affecting the northern mid-latitudes at typical flight altitudes (7-12 km). This largely contributes to the overall change in particle number concentration between 2000 and 2030, which also results in significant climate effects due to aerosol-cloud interactions. Aviation is the only transport sector for which a larger impact on the Earth's radiation budget is simulated in the future: the aviation-induced radiative forcing in 2030 is more than doubled with respect to the year 2000 value of -15 mW m-2 in all scenarios, with a maximum value of -63 mW m-2 simulated for RCP2.6.

  5. Estimating the effectiveness of using atmospheric deaerators for decarbonizing makeup water

    Science.gov (United States)

    Larin, B. M.; Larin, A. B.

    2015-02-01

    According to the water coolant quality standards, the makeup water supplied to a thermal power plant's (TPP) steam-generating systems must not have any content of free carbonic acid. As a rule, free and partially bound carbonic acid is removed from makeup water supplied to the power-generating boilers at TPPs in atmospheric deaerators. Their performance as decarbonizers can be evaluated by measuring the pH values of water supplied to the deaerator and of the deaerated water. A procedure for calculating the residual concentration of carbonic acid in deaerated water and the decarbonization effect from the change in the pH value (ΔpH) is presented together with an example of calculation carried out by specialists of the Ivanovo State Power Engineering University based on a long-term industrial experiment performed on DSA-300 atmospheric deaerators.

  6. Strong Water Isotopic Anomalies in the Martian Atmosphere: Probing Current and Ancient Reservoirs

    Science.gov (United States)

    Villanueva, G. L.; Mumma, M. J.; Novak, R. E.; Käufl, H. U.; Hartogh, P.; Encrenaz, T.; Tokunaga, A.; Khayat, A.; Smith, M. D.

    2015-01-01

    We measured maps of atmospheric water (H2O) and its deuterated form (HDO) across the martian globe, showing strong isotopic anomalies and a significant high deuterium/hydrogen (D/H) enrichment indicative of great water loss. The maps sample the evolution of sublimation from the north polar cap, revealing that the released water has a representative D/H value enriched by a factor of about 7 relative to Earth's ocean [Vienna standard mean ocean water (VSMOW)]. Certain basins and orographic depressions show even higher enrichment, whereas high-altitude regions show much lower values (1 to 3 VSMOW). Our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 VSMOW, which would mean that early Mars (4.5 billion years ago) had a global equivalent water layer at least 137 meters deep.

  7. Relative Influence of Initial Surface and Atmospheric Conditions on Seasonal Water and Energy Balances

    Science.gov (United States)

    Oglesby, Robert J.; Marshall, Susan; Roads, John O.; Robertson, Franklin R.; Goodman, H. Michael (Technical Monitor)

    2001-01-01

    We constructed and analyzed wet and dry soil moisture composites for the mid-latitude GCIP region of the central US using long climate model simulations made with the NCAR CCM3 and reanalysis products from NCEP. Using the diagnostic composites as a guide, we have completed a series of predictability experiments in which we imposed soil water initial conditions in CCM3 for the GCIP region for June 1 from anomalously wet and dry years, with atmospheric initial conditions taken from June 1 of a year with 'near-normal' soil water, and initial soil water from the near-normal year and atmospheric initial conditions from the wet and dry years. Preliminary results indicate that the initial state of the atmosphere is more important than the initial state of soil water determining the subsequent late spring and summer evolution of sod water over the GCIP region. Surprisingly, neither the composites or the predictability experiments yielded a strong influence of soil moisture on the atmosphere. To explore this further, we have made runs with extreme dry soil moisture initial anomalies imposed over the GCIP region (the soil close to being completely dry). These runs did yield a very strong effect on the atmosphere that persisted for at least three months. We conclude that the magnitude of the initial soil moisture anomaly is crucial, at least in CCM3, and are currently investigating whether a threshold exists, below which little impact is seen. In a complementary study, we compared the impact of the initial condition of snow cover versus the initial atmospheric state over the western US (corresponding to the westward extension of the GAPP program follow-on to GCIP). In this case, the initial prescription of snow cover is far more important than the initial atmospheric state in determining the subsequent evolution of snow cover. We are currently working to understand the very different soil water and snow cover results.

  8. Calibration of a ground water contamination transport model using Tritium-3Helium ages

    International Nuclear Information System (INIS)

    Full text: Dow Terneuzen is the largest US chemical industrial site in Europe. Situated in the southern part of The Netherlands at the southern shore of the Westershelde, the site occupies an area of roughly 2km times 3km. Several contaminant plumes are known in the ground water below the industrial area. They originate from accidents in the fifties until seventies and are transported with the ground water flow towards the borders of the site. Detailed hydrogeological investigations lead to a three-dimensional numerical model of ground water flow and transport. Although this model was carefully calibrated using the hydraulic heads, unrealistic travel times and ground water ages were obtained. In a case study one of the contaminant plumes was investigated for ground water age and distance velocity. Out of three multilevel wells along the plume a total of 13 samples for T/3He were obtained. All samples contained tritium, indicating a component of ground water younger than 40 years, whereas the numerical model gave travel times between 40 and 160 years. The Tritium data are further confirmed by SF6 which was present in concentrations well above the present day atmospheric equilibrium in two out of three samples. Two facts hamper the interpretation of the noble gas data as T/3He ages: i) Degradation of the organic contaminant (benzene) results in CO2 and CH4 production causing loss of noble gases in the aquifer by a stripping process. This also caused problems during the sampling and made the interpretation of the data as ages impossible for 5 of the 13 samples. ii) Ground water infiltration temperatures are unknown but elevated due to process heat released from the industrial environment. Accuracy of the derived ages is limited mainly by this unknown infiltration temperature. Despite these difficulties the derived T/ 3 He ages give clear hints for the improvement of the numerical model. Most probably ground water infiltration does not take place on the whole area as

  9. Calibration of a ground water contamination transport model using Tritium-3Helium ages

    International Nuclear Information System (INIS)

    Full text: Dow Terneuzen is the largest US chemical industrial site in Europe. Situated in the southern part of The Netherlands at the southern shore of the Westershelde, the site occupies an area of roughly 2km times 3km. Several contaminant plumes are known in the ground water below the industrial area. They originate from accidents in the fifties until seventies and are transported with the ground water flow towards the borders of the site. Detailed hydrogeological investigations lead to a three-dimensional numerical model of ground water flow and transport. Although this model was carefully calibrated using the hydraulic heads, unrealistic travel times and ground water ages were obtained. In a case study one of the contaminant plumes was investigated for ground water age and distance velocity. Out of three multilevel wells along the plume a total of 13 samples for T/3He were obtained. All samples contained tritium, indicating a component of ground water younger than 40 years, whereas the numerical model gave travel times between 40 and 160 years. The Tritium data are further confirmed by SF6 which was present in concentrations well above the present day atmospheric equilibrium in two out of three samples. Two facts hamper the interpretation of the noble gas data as T/3He ages: i) Degradation of the organic contaminant (benzene) results in CO2 and CH4 production causing loss of noble gases in the aquifer by a stripping process. This also caused problems during the sampling and made the interpretation of the data as ages impossible for 5 of the 13 samples. ii) Ground water infiltration temperatures are unknown but elevated due to process heat released from the industrial environment. Accuracy of the derived ages is limited mainly by this unknown infiltration temperature. Despite these difficulties the derived T/3He ages give clear hints for the improvement of the numerical model. Most probably ground water infiltration does not take place on the whole area as

  10. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong

    2015-06-01

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  11. Long-range transport of radioisotopes in the atmosphere and the calculation of collective dose

    International Nuclear Information System (INIS)

    In estimating the long range (up to 1000 km) transport and dispersal of atmospheric pollutants, the meteorological conditions at the source become less relevant as the distance from the source increases, making it difficult to extrapolate to larger distances using short range modelling techniques. The MESOS model has therefore been developed to take into account the temporal and spatial changes in the atmospheric boundary layer along the trajectory of a pollutant release, including the effects of diurnal cycle and lateral dispersion in the synoptic scale windfield. The model is described together with the associated data base incorporating a year's meteorological data from synoptic stations and ships across Western Europe. A simulation of dispersal following the Windscale release of 1957 is compared with measurements. The use of the model is further illustrated by application to a hypothetical site both for routine continuous releases and short term accidental releases. This work has been carried out within the framework of a research contract between the EURATOM-CEA Association and Imperial College. (H.K.)

  12. Long-range atmospheric transport of pollutants to the Eastern Mediterranean basin

    International Nuclear Information System (INIS)

    A permanent stations has been established in the Eastern Mediterranean coast of Turkey for continuous monitoring of aerosols and precipitation. The station is part of the MED-POL programme which includes all countries that have coasts in the Mediterranean Sea and attempts to determine the role of the atmospheric fluxes of pollutants on the pollution of the Mediterranea Sea. Aerosol and deposition samples have been collected since early 1992. Concentrations of SO4, NO3, Cl, Li, Pb, K, Ca, Al, As, Cd, Cr, Cu, Se, Zn and Na were determined by ion chromatography and atomic absorption spectrometry. Daily samples will be screened to select the ones which correspond to transport from Europe and will be analyzed for a larger number of parameters using INAA. Method development took most of the time in 1992, and analysis are still in progress. Available data have shown that concentrations of anthropogenic elements are smaller in the Eastern Mediterranean atmosphere compared to other rural sites in the Europe. (author). 21 refs, 8 figs, 6 tabs

  13. Atmospheric transport of contaminants to remote arctic wilderness areas: A pilot study

    International Nuclear Information System (INIS)

    The Alaska Maritime National Wildlife Refuge includes the Tuxedni Wilderness Area (WA), which is required to meet the Class 1 air quality requirements of the Clean Air Act (42 CFT 7401 et seq.). The Act specifically protects such areas from significant deterioration; however, most Class 1 Wilderness monitoring focuses on visual impairment and traditional atmospheric pollutants such as NOx. This study was designed to assess the feasibility of also measuring atmospheric transport of potentially toxic elemental and organic contaminants to remote areas as a pilot for subsequent monitoring of Service lands to be undertaken through the Biomonitoring of Environmental Status and Trends (BEST) Program. Located on the western shore of Cook Inlet, the Tuxedni WA lies about 80 km downwind of a major petroleum complex that the City of Anchorage. Elemental contaminants emanating from the city will be studied in two species of widely distributed alpine vegetation (Cladina rangiferina, a lichen; and Hylocomium splendens, a moss) collected from elevated windward slopes on Chisik Island, a remote site in the WA. Vegetation samples will be analyzed for a suite of potentially toxic elements by inductively coupled plasma emission spectrometry and atomic absorption spectrophotometry. Polycyclic aromatic compounds originating from petroleum-related and urban sources will be studied through the deployment of lipid-containing passive accumulators and analysis by gas chromatography with photoionization detection. Reference areas will also be selected and monitored

  14. Investigation of hurricane Ivan using the coupled ocean-atmosphere-wave-sediment transport (COAWST) model

    Science.gov (United States)

    Zambon, Joseph B.; He, Ruoying; Warner, John C.

    2014-01-01

    The coupled ocean–atmosphere–wave–sediment transport (COAWST) model is used to hindcast Hurricane Ivan (2004), an extremely intense tropical cyclone (TC) translating through the Gulf of Mexico. Sensitivity experiments with increasing complexity in ocean–atmosphere–wave coupled exchange processes are performed to assess the impacts of coupling on the predictions of the atmosphere, ocean, and wave environments during the occurrence of a TC. Modest improvement in track but significant improvement in intensity are found when using the fully atmosphere–ocean-wave coupled configuration versus uncoupled (e.g., standalone atmosphere, ocean, or wave) model simulations. Surface wave fields generated in the fully coupled configuration also demonstrates good agreement with in situ buoy measurements. Coupled and uncoupled model-simulated sea surface temperature (SST) fields are compared with both in situ and remote observations. Detailed heat budget analysis reveals that the mixed layer temperature cooling in the deep ocean (on the shelf) is caused primarily by advection (equally by advection and diffusion).

  15. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    International Nuclear Information System (INIS)

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  16. Water security, global change and land-atmosphere feedbacks.

    Science.gov (United States)

    Dadson, Simon; Acreman, Michael; Harding, Richard

    2013-11-13

    Understanding the competing pressures on water resources requires a detailed knowledge of the future water balance under uncertain environmental change. The need for a robust, scientifically rigorous evidence base for effective policy planning and practice has never been greater. Environmental change includes, but is not limited to, climate change; it also includes land-use and land-cover change, including deforestation for agriculture, and occurs alongside changes in anthropogenic interventions that are used in natural resource management such as the regulation of river flows using dams, which can have impacts that frequently exceed those arising in the natural system. In this paper, we examine the role that land surface models can play in providing a robust scientific basis for making resource management decisions against a background of environmental change. We provide some perspectives on recent developments in modelling in land surface hydrology. Among the range of current land surface and hydrology models, there is a large range of variability, which indicates that the specification and parametrization of several basic processes in the models can be improved. Key areas that require improvement in order to address hydrological applications include (i) the representation of groundwater in models, particularly at the scales relevant to land surface modelling, (ii) the representation of human interventions such as dams and irrigation in the hydrological system, (iii) the quantification and communication of uncertainty, and (iv) improved understanding of the impact on water resources availability of multiple use through treatment, recycling and return flows (and the balance of consumptive and conservative uses). Through a series of examples, we demonstrate that changes in water use could have important reciprocal impacts on climate over a wide area. The effects of water management decisions on climate feedbacks are only beginning to be investigated-they are

  17. Large Eddy Simulation and Field Experiments of Pollen Transport in the Atmospheric Boundary Layer

    Science.gov (United States)

    Chamecki, M.; Meneveau, C.; Parlange, M. B.; van Hout, R.

    2006-12-01

    Dispersion of airborne pollen by the wind has been a subject of interest for botanists and allergists for a long time. More recently, the development of genetically modified crops and questions about cross-pollination and subsequent contamination of natural plant populations has brought even more interest to this field. A critical question is how far from the source field pollen grains will be advected. Clearly the answer depends on the aerodynamic properties of the pollen, geometrical properties of the field, topography, local vegetation, wind conditions, atmospheric stability, etc. As a consequence, field experiments are well suited to provide some information on pollen transport mechanisms but are limited to specific field and weather conditions. Numerical simulations do not have this drawback and can be a useful tool to study pollen dispersal in a variety of configurations. It is well known that the dispersion of particles in turbulent fields is strongly affected by the large scale coherent structures. Large Eddy Simulation (LES) is a technique that allows us to study the typical distances reached by pollen grains and, at the same time, resolve the larger coherent structures present in the atmospheric boundary layer. The main objective of this work is to simulate the dispersal of pollen grains in the atmospheric surface layer using LES. Pollen concentrations are simulated by an advection-diffusion equation including gravitational settling. Of extreme importance is the specification of the bottom boundary conditions characterizing the pollen source over the canopy and the deposition process everywhere else. In both cases we make use of the theoretical profile for suspended particles derived by Kind (1992). Field experiments were performed to study the applicability of the theoretical profile to pollen grains and the results are encouraging. Airborne concentrations as well as ground deposition from the simulations are compared to experimental data to validate the

  18. The MATS experiments - mesoscale atmospheric transport studies at the Savannah River Site

    International Nuclear Information System (INIS)

    An overview of the Mesoscale Atmospheric Transport Studies (MATS) program is presented. MATS was an experimental program to create a data base for short-term atmospheric releases to study mesoscale atmospheric dispersion over gently rolling terrain at the Savannah River Site (SRS). Thirty-one experiments were performed over a 3-year period under daytime convective conditions using 15-minute releases of sulfur hexafluoride (SF6) tracer. Dispersion was typically measured along an arc of stationary samplers approximately 30 km downwind. Four nighttime experiments were performed with SF6 releases, and sampling was carried on for a few hours with a mobile sampling laboratory. The mobile laboratory repeatedly traversed the plume while recording tracer concentration, time, and location. Supporting meteorological data for the MATS experiments included wind and temperature measurements from an integrated meteorological tower network and computer system. The tower network consists of eight instrumented, 61-m towers located near each of SRS's major facilities and a 304-m television tower located about 16 km WNW from the SRS administrative area. Low-level soundings obtained from on-site launches of mini-rawinsondes and Airsondes provided additional date on the vertical structure of the boundary layer for 11 of the experiments. Soundings were also obtained for Athens, GA., and Charleston, SC, from the National Climatic Data Center. The MATS data set is available for use by diffusion researchers and modelers. Two experiments were examined in detail and compared with predictions from a simple Gaussian model to help demonstrate the usefulness of the data. These cases show that the downwind locations of tracer material were predicted adequately if uniform winds at release level were assumed but that the magnitude of the concentration was overpredicted by factors of 2.5 and 10. 21 refs., 14 figs., 4 tabs

  19. Atmospheric transport and chemistry of trace gases in LMDz5B: evaluation and implications for inverse modelling

    OpenAIRE

    Locatelli, R.; Bousquet, P.; Hourdin, F.; Saunois, M.; COZIC A.; Couvreux, F; Grandpeix, J.-Y.; Lefebvre, M.-P.; C. Rio; Bergamaschi, P.; Chambers, S. D.; U. Karstens; Kazan, V.; S. Van der Laan; Meijer, H. A. J.

    2015-01-01

    Representation of atmospheric transport is a major source of error in the estimation of greenhouse gas sources and sinks by inverse modelling. Here we assess the impact on trace gas mole fractions of the new physical parameterizations recently implemented in the atmospheric global climate model LMDz to improve vertical diffusion, mesoscale mixing by thermal plumes in the planetary boundary layer (PBL), and deep convection in the troposphere. At the same time, the horizontal ...

  20. A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

    OpenAIRE

    Xi Xi

    2014-01-01

    Stable water isotopologues, mainly ^1H_2O, ^1H^2HO (HDO), and ^1H_2 ^(18)O, are useful tracers for processes in the global hydrological cycle. The incorporation of water isotopes into Atmospheric General Circulation Models (AGCMs) since 1984 has helped scientists gain substantial new insights into our present and past climate. In recent years, there have been several significant advances in water isotopes modeling in AGCMs. This paper reviews and synthesizes key advances accomplis...

  1. Precipitation efficiency derived from isotope ratios in water vapor distinguishes dynamical and microphysical influences on subtropical atmospheric constituents

    Science.gov (United States)

    Bailey, A.; Nusbaumer, J.; Noone, D.

    2015-09-01

    With water vapor and clouds expected to effect significant feedbacks on climate, moisture transport through convective processes has important implications for future temperature change. The precipitation efficiency—the ratio of the rates at which precipitation and condensation form (e = P/C)—is useful for characterizing how much boundary layer moisture recycles through precipitation versus mixes into the free troposphere through cloud detrainment. Yet it is a difficult metric to constrain with traditional observational techniques. This analysis characterizes the precipitation efficiency of convection near the Big Island of Hawaii, USA, using a novel tracer: isotope ratios in water vapor. The synoptic circulation patterns associated with high and low precipitation efficiency are identified, and the importance of large-scale dynamics and local convective processes in regulating vertical distributions of atmospheric constituents important for climate is evaluated. The results suggest that high e days are correlated with plume-like transport originating from the relatively clean tropics, while low e days are associated with westerly transport, generated by a branching of the jet stream. Differences in transport pathway clearly modify background concentrations of water vapor and other trace gases measured at Mauna Loa Observatory; however, local convective processes appear to regulate aerosols there. Indeed, differences between observed and simulated diurnal cycles of particle number concentration indicate that precipitation scavenges aerosols and possibly facilitates new particle formation when e is high. As measurements of isotope ratios in water vapor expand across the subtropics, the techniques presented here can further our understanding of how synoptic weather, precipitation processes, and climate feedbacks interrelate.

  2. The role of atmospheric precipitation in introducing contaminants to the surface waters of the Fuglebekken catchment, Spitsbergen

    Directory of Open Access Journals (Sweden)

    Katarzyna Kozak

    2015-11-01

    Full Text Available Although the Svalbard Archipelago is located at a high latitude, far from potential contaminant sources, it is not free from anthropogenic impact. Towards the Fuglebekken catchment, in the southern part of Spitsbergen, north of Hornsund fjord, contaminants can be transported from mainland pollution sources. In the precipitation and surface water collected in the catchment, the following elements were detected and quantified: Ag, Al, As, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Cs, Mo, Ni, Pb, Sb, Se, Sr, Tl, U, V and Zn. Additionally, pH, electrical conductivity and total organic carbon (TOC were determined in those samples. The acidic reaction of precipitation waters was identified as an important factor intensifying the metal migration in this Arctic tundra environment. The air mass trajectory, surprisingly, explained the variability of only a small fraction of trace elements in precipitation water. The air mass origin area was correlated only with the concentrations of As, V and Cr. Wind directions were helpful in explaining the variability of Mn, U and Ba concentrations (east–north-easterly wind and the contents of B, As, Rb, Se, Sr and Li in precipitation (south-westerly wind, which may indicate the local geological source of those. Atmospheric deposition was found to play a key role in the transport of contaminants into the Fuglebekken catchment; however, the surface water composition was modified by its pH and TOC content.

  3. Water loss from terrestrial planets with CO{sub 2}-rich atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Wordsworth, R. D.; Pierrehumbert, R. T., E-mail: rwordsworth@uchicago.edu [Department of the Geophysical Sciences, University of Chicago, 60637 IL (United States)

    2013-12-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO{sub 2} can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO{sub 2} atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO{sub 2}-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ∼270 W m{sup –2} (global mean) unlikely to lose more than one Earth ocean of H{sub 2}O over their lifetimes unless they lose all their atmospheric N{sub 2}/CO{sub 2} early on. Because of the variability of H{sub 2}O delivery during accretion, our results suggest that many 'Earth-like' exoplanets in the habitable zone may have ocean-covered surfaces, stable CO{sub 2}/H{sub 2}O-rich atmospheres, and high mean surface temperatures.

  4. TIPEX (Tropical Indo-Pacific water transport and ecosystem monitoring EXperiment Program

    Directory of Open Access Journals (Sweden)

    Dongchull Jeon

    2013-09-01

    Full Text Available One of the factors influencing the climate around Korea is the oceanic-atmospheric variability in the tropical region between the eastern Indian and the western Pacific Oceans. Lack of knowledge about the air-sea interaction in the tropical Indo-Pacific region continues to make it problematic forecasting the ocean climate in the East Asia. The ‘Tropical Indo-Pacific water transport and ecosystem monitoring EXperiment (TIPEX’ is a program for monitoring the ocean circulation variability between Pacific and Indian Oceans and for improving the accuracy of future climate forecasting. The main goal of the TIPEX program is to quantify the climate and ocean circulation change between the Indian and the Pacific Oceans. The contents of the program are 1 to observe the mixing process of different water masses and water transport in the eastern Indian and the western Pacific, 2 to understand the large-scale oceanic-climatic variation including El Niño-Southern Oscillation (ENSO/Warm Pool/Pacific Decadal Oscillation (PDO/Indian Ocean Dipole (IOD, and 3 to monitor the biogeochemical processes, material flux, and biological changes due to the climate change. In order to effectively carry out the monitoring program, close international cooperation and the proper co-work sharing of tasks between China, Japan, Indonesia, and India as well as USA is required.

  5. Towards quantitative atmospheric water vapor profiling with differential absorption lidar.

    Science.gov (United States)

    Dinovitser, Alex; Gunn, Lachlan J; Abbott, Derek

    2015-08-24

    Differential Absorption Lidar (DIAL) is a powerful laser-based technique for trace gas profiling of the atmosphere. However, this technique is still under active development requiring precise and accurate wavelength stabilization, as well as accurate spectroscopic parameters of the specific resonance line and the effective absorption cross-section of the system. In this paper we describe a novel master laser system that extends our previous work for robust stabilization to virtually any number of multiple side-line laser wavelengths for the future probing to greater altitudes. In this paper, we also highlight the significance of laser spectral purity on DIAL accuracy, and illustrate a simple re-arrangement of a system for measuring effective absorption cross-section. We present a calibration technique where the laser light is guided to an absorption cell with 33 m path length, and a quantitative number density measurement is then used to obtain the effective absorption cross-section. The same absorption cell is then used for on-line laser stabilization, while microwave beat-frequencies are used to stabilize any number of off-line lasers. We present preliminary results using ∼300 nJ, 1 μs pulses at 3 kHz, with the seed laser operating as a nanojoule transmitter at 822.922 nm, and a receiver consisting of a photomultiplier tube (PMT) coupled to a 356 mm mirror. PMID:26368258

  6. Atmospheric transport simulations in support of the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE)

    Science.gov (United States)

    Henderson, J. M.; Eluszkiewicz, J.; Mountain, M. E.; Nehrkorn, T.; Chang, R. Y.-W.; Karion, A.; Miller, J. B.; Sweeney, C.; Steiner, N.; Wofsy, S. C.; Miller, C. E.

    2015-04-01

    This paper describes the atmospheric modeling that underlies the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) science analysis, including its meteorological and atmospheric transport components (polar variant of the Weather Research and Forecasting (WRF) and Stochastic Time Inverted Lagrangian Transport (STILT) models), and provides WRF validation for May-October 2012 and March-November 2013 - the first 2 years of the aircraft field campaign. A triply nested computational domain for WRF was chosen so that the innermost domain with 3.3 km grid spacing encompasses the entire mainland of Alaska and enables the substantial orography of the state to be represented by the underlying high-resolution topographic input field. Summary statistics of the WRF model performance on the 3.3 km grid indicate good overall agreement with quality-controlled surface and radiosonde observations. Two-meter temperatures are generally too cold by approximately 1.4 K in 2012 and 1.1 K in 2013, while 2 m dewpoint temperatures are too low (dry) by 0.2 K in 2012 and too high (moist) by 0.6 K in 2013. Wind speeds are biased too low by 0.2 m s-1 in 2012 and 0.3 m s-1 in 2013. Model representation of upper level variables is very good. These measures are comparable to model performance metrics of similar model configurations found in the literature. The high quality of these fine-resolution WRF meteorological fields inspires confidence in their use to drive STILT for the purpose of computing surface influences ("footprints") at commensurably increased resolution. Indeed, footprints generated on a 0.1° grid show increased spatial detail compared with those on the more common 0.5° grid, better allowing for convolution with flux models for carbon dioxide and methane across the heterogeneous Alaskan landscape. Ozone deposition rates computed using STILT footprints indicate good agreement with observations and exhibit realistic seasonal variability, further indicating that WRF

  7. Global atmospheric emissions and transport of polycyclic aromatic hydrocarbons: Evaluation of modeling and transboundary pollution

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2014-05-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimated country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). MOZART-4 (The Model for Ozone and Related Chemical Tracers, version 4) was applied to simulate the global tropospheric transport of Benzo(a)pyrene, one of the high molecular weight carcinogenic PAHs, at a horizontal resolution of 1.875° (longitude) × 1.8947° (latitude). The reaction with OH radical, gas/particle partitioning, wet deposition, dry deposition, and dynamic soil/ocean-air exchange of PAHs were considered. The simulation was validated by observations at both background and non-background sites, including Alert site in Canadian High Arctic, EMEP sites in Europe, and other 254 urban/rural sites reported from literatures. Key factors effecting long-range transport of BaP were addressed, and transboundary pollution was discussed.

  8. Solar radiation transport in the cloudy atmosphere: a 3D perspective on observations and climate impacts

    International Nuclear Information System (INIS)

    The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.

  9. Downward transport of ozone rich air and implications for atmospheric chemistry in the Amazon rainforest

    Science.gov (United States)

    Gerken, Tobias; Wei, Dandan; Chase, Randy J.; Fuentes, Jose D.; Schumacher, Courtney; Machado, Luiz A. T.; Andreoli, Rita V.; Chamecki, Marcelo; Ferreira de Souza, Rodrigo A.; Freire, Livia S.; Jardine, Angela B.; Manzi, Antonio O.; Nascimento dos Santos, Rosa M.; von Randow, Celso; dos Santos Costa, Patrícia; Stoy, Paul C.; Tóta, Julio; Trowbridge, Amy M.

    2016-01-01

    From April 2014 to January 2015, ozone (O3) dynamics were investigated as part of GoAmazon 2014/5 project in the central Amazon rainforest of Brazil. Just above the forest canopy, maximum hourly O3 mixing ratios averaged 20 ppbv (parts per billion on a volume basis) during the June-September dry months and 15 ppbv during the wet months. Ozone levels occasionally exceeded 75 ppbv in response to influences from biomass burning and regional air pollution. Individual convective storms transported O3-rich air parcels from the mid-troposphere to the surface and abruptly enhanced the regional atmospheric boundary layer by as much as 25 ppbv. In contrast to the individual storms, days with multiple convective systems produced successive, cumulative ground-level O3 increases. The magnitude of O3 enhancements depended on the vertical distribution of O3 within storm downdrafts and origin of downdrafts in the troposphere. Ozone mixing ratios remained enhanced for > 2 h following the passage of storms, which enhanced chemical processing of rainforest-emitted isoprene and monoterpenes. Reactions of isoprene and monoterpenes with O3 are modeled to generate maximum hydroxyl radical formation rates of 6 × 106 radicals cm-3s-1. Therefore, one key conclusion of the present study is that downdrafts of convective storms are estimated to transport enough O3 to the surface to initiate a series of reactions that reduce the lifetimes of rainforest-emitted hydrocarbons.

  10. Rain pattern analysis and forecast model based on GPS estimated atmospheric water vapor content

    OpenAIRE

    Priego De Los Santos, Enrique

    2012-01-01

    Rain is one of the fundamental processes of the hydrologic cycle as it can be the source of wealth or natural hazards. This experiment focuses in the relationship between rain occurrence and atmospheric pressure (Patm) and atmospheric water vapor content (PW), GPS estimated. The available nine years time series of each variable were analyzed. It allowed to state the existence of three rain patterns and monthly differences in the Patm-PW combinations. In spite of rain episodes take place only ...

  11. Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS and radiosondes

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2011-05-01

    Full Text Available An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002–2010 and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA. We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time.

    We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical

  12. Modeling of Water Flow Processes in the Soil-Plant-Atmosphere System: The Soil-Tree-Atmosphere Continuum Model

    Science.gov (United States)

    Massoud, E. C.; Vrugt, J. A.

    2015-12-01

    Trees and forests play a key role in controlling the water and energy balance at the land-air surface. This study reports on the calibration of an integrated soil-tree-atmosphere continuum (STAC) model using Bayesian inference with the DREAM algorithm and temporal observations of soil moisture content, matric head, sap flux, and leaf water potential from the King's River Experimental Watershed (KREW) in the southern Sierra Nevada mountain range in California. Water flow through the coupled system is described using the Richards' equation with both the soil and tree modeled as a porous medium with nonlinear soil and tree water relationships. Most of the model parameters appear to be reasonably well defined by calibration against the observed data. The posterior mean simulation reproduces the observed soil and tree data quite accurately, but a systematic mismatch is observed between early afternoon measured and simulated sap fluxes. We will show how this points to a structural error in the STAC-model and suggest and test an alternative hypothesis for root water uptake that alleviates this problem.

  13. Atmospheric transport and deposition of pesticides: An assessment of current knowledge

    DEFF Research Database (Denmark)

    Pul, W.A.J. van; Bidleman, T.F.; Brorström-Lunden, E.;

    1999-01-01

    there is a shortage of measurement data to evaluate the deposition and reemission processes. It was concluded that the mechanisms of transport and dispersion of pesticides can be described similarly to those for other air pollution components and these mechanisms are rather well-known. Large uncertainties are present...... in the exchange processes at the interface between air and soil/water/vegetation. In all process descriptions the uncertainty in the physicochemical properties play an important role. Particularly those in the vapour pressure, Henry's law constant and its temperature dependency. More accurate data...

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

    Science.gov (United States)

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

    2013-04-01

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

  15. Atmospheric moisture transport: the bridge between ocean evaporation and Arctic ice melting

    Science.gov (United States)

    Gimeno, L.; Vázquez, M.; Nieto, R.; Trigo, R. M.

    2015-09-01

    Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting some of the most significant changes in the Arctic region. The increasing moisture over the Arctic during the last decades is not strongly associated with the evaporation that takes place within the Arctic area itself, despite the fact that the sea ice cover is decreasing. Such an increment is consistent and is more dependent on the transport of moisture from the extratropical regions to the Arctic that has increased in recent decades and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the more objective assessment of the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyse several recent results suggesting links between moisture transport and the extent of sea ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnecting results, using new information and insights. Results reached in this study stress the connection between two climate change indicators, namely an increase in evaporation over source regions (mainly the Mediterranean Sea, the North Atlantic Ocean and the North Pacific Ocean in the paths of the global western boundary currents and their extensions) and Arctic ice melting precursors.

  16. Two dimensional model study of atmospheric transport using carbon-14 and strontium-90 as inert tracers

    International Nuclear Information System (INIS)

    This study tests the transport processes in the LLNL two-dimensional chemical-radiative-transport model using recently reanalyzed carbon-14 and strontium-90 data. These radioactive tracers were produced bythe atmospheric nuclear bomb tests of 1952--58 and 1961--62, and they were measured at a few latitudes up to 35 kilometers over the period 1955--1970. Selected horizontal and vertical eddy diffusion coefficients were varied in the model to test their sensitivity to short and long term transpose of carbon-14. A sharp transition of Kzz and Kyy through the tropopause, as opposed to a slow transition between the same limiting values, shows a distinct improvement in the calculated carbon-14 distributions, a distinct improvement in the calculated seasonal and latitudinal distribution of ozone columns (relative to TOMS observations), and a very large difference in the calculated ozone reduction by a possible fleet of High Speed Civil Transports. Calculated northern hemisphere carbon-14 is more sensitive to variation of Kyy than are global ozone columns. Strontium-90 was used to test the LLNL tropopause height at four different latitudes. Starting with the 1960 background distribution of carbon-14, we calculate the input of carbon-14 as the sum of each nuclear test of the 1961--62 series, using two bomb-cloud rise models. With the Seitz bomb-rise formulation in the LLNL model, we find good agreement between calculated and observedcarbon-14 (with noticeable exceptions at the north polar tropopause and the short-term mid-latitude mid-stratosphere) between 1963 and 1970

  17. The water cycle in the general circulation model of the martian atmosphere

    Science.gov (United States)

    Shaposhnikov, D. S.; Rodin, A. V.; Medvedev, A. S.

    2016-03-01

    Within the numerical general-circulation model of the Martian atmosphere MAOAM (Martian Atmosphere: Observation and Modeling), we have developed the water cycle block, which is an essential component of modern general circulation models of the Martian atmosphere. The MAOAM model has a spectral dynamic core and successfully predicts the temperature regime on Mars through the use of physical parameterizations typical of both terrestrial and Martian models. We have achieved stable computation for three Martian years, while maintaining a conservative advection scheme taking into account the water-ice phase transitions, water exchange between the atmosphere and surface, and corrections for the vertical velocities of ice particles due to sedimentation. The studies show a strong dependence of the amount of water that is actively involved in the water cycle on the initial data, model temperatures, and the mechanism of water exchange between the atmosphere and the surface. The general pattern and seasonal asymmetry of the water cycle depends on the size of ice particles, the albedo, and the thermal inertia of the planet's surface. One of the modeling tasks, which results from a comparison of the model data with those of the TES experiment on board Mars Global Surveyor, is the increase in the total mass of water vapor in the model in the aphelion season and decrease in the mass of water ice clouds at the poles. The surface evaporation scheme, which takes into account the turbulent rise of water vapor, on the one hand, leads to the most complete evaporation of ice from the surface in the summer season in the northern hemisphere and, on the other hand, supersaturates the atmosphere with ice due to the vigorous evaporation, which leads to worse consistency between the amount of the precipitated atmospheric ice and the experimental data. The full evaporation of ice from the surface increases the model sensitivity to the size of the polar cap; therefore, the increase in the

  18. Transport processes induced by metastable boiling water under Martian surface conditions

    Science.gov (United States)

    Massé, M.; Conway, S. J.; Gargani, J.; Patel, M. R.; Pasquon, K.; McEwen, A.; Carpy, S.; Chevrier, V.; Balme, M. R.; Ojha, L.; Vincendon, M.; Poulet, F.; Costard, F.; Jouannic, G.

    2016-06-01

    Liquid water may exist on the Martian surface today, albeit transiently and in a metastable state under the low atmospheric surface pressure. However, the identification of liquid water on Mars from observed morphological changes is hampered by our limited understanding of how metastable liquids interact with sediments. Here, we present lab experiments in which a block of ice melts and seeps into underlying sediment, and the resulting downslope fluid propagation and sediment transport are tracked. In experiments at Martian surface pressure, we find that pure water boils as it percolates into the sediment, inducing grain saltation and leading to wholesale slope destabilization: a hybrid flow mechanism involving both wet and dry processes. For metastable brines, which are more stable under Martian conditions than pure water, saltation intensity and geomorphological impact are reduced; however, we observed channel formation in some briny flow experiments that may be analogous to morphologies observed on Mars. In contrast, under terrestrial-like experimental conditions, there is little morphological impact of seeping water or brine, which are both stable. We propose that the hybrid flow mechanism operating in our experiments under Martian surface pressure could explain observed Martian surface changes that were originally interpreted as the products of either dry or wet processes.

  19. Simulation of atmospheric krypton-85 transport to assess the detectability of clandestine nuclear reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Jens Ole

    2010-02-02

    The radioactive noble gas krypton-85 is released into the atmosphere during reprocessing of spent nuclear fuel or irradiated breeding targets. This is a necessary step for plutonium separation. Therefore the {sup 85}Kr signature of reprocessing could possibly be used for the detection of undeclared nuclear facilities producing nuclear weaponusable material. The {sup 85}Kr content of the atmosphere has grown over the last decades as the emissions from military and civilian nuclear industry could not be compensated by the decay with a half-life of 10.76 years. In this study, the global {sup 85}Kr background distribution due to emissions of known reprocessing facilities for the period from 1971 until 2006 was simulated using the atmospheric general circulation model ECHAM5 applying the newest available annual emission data. The convective tracer transport scheme and the operator splitting for the physical calculations in the model were modified in order to guarantee physically correct results for tracer point sources, in particular non negative concentrations. An on-line routine controlling the {sup 85}Kr -budget in the model enforced exact mass conservation. The results of the simulation were evaluated by extensive comparison with measurements performed by the German Federal Office for Radiation Protection with very good agreement at most observation sites except those in the direct vicinity of {sup 85}Kr sources. Of particular interest for the {sup 85}Kr detection potential was the variability of {sup 85}Kr background concentrations which was evaluated for the first time in a global model. In addition, the interhemispheric transport as simulated by ECHAM5 was analyzed using a two-box model providing a mean exchange time of τ {sub ex} = 10.5 months. The analysis of τ{sub ex} over simulated 35 years indicates that in years with strong South Asian or African Monsoon the interhemispheric transport is faster during the monsoon season. A correlation analysis of

  20. Long-living plasmoids from an atmospheric water discharge

    International Nuclear Information System (INIS)

    Ball-like plasmoids were generated from discharging a capacitor bank via a water surface. In the autonomous stage after current zero they have diameters up to 0.2 m and lifetimes of some hundreds of milliseconds, thus resembling ball lightning in some way. They were studied by applying high speed cameras, electric probes, calorimetric measurements, and spectroscopy. The plasmoids are found to consist of a true plasma surrounded by a cold envelope. Decreasing electron densities in the order of 1020-1022 m-3 were measured from Stark broadening in the initial (formation) phase. The electron temperature is estimated to be 2000-5000 K during most of the plasmoid's lifetime. The temperature of the neutral particles can exceed 1300 K. Calcium hydroxide molecular band emission is the major source of visible radiation in the autonomous phase. Chemiluminescence reactions between dissociation products of water and dissolved calcium are proposed as a source for this emission. The plasmoid's colder boundary layer consists of electric double layers that may be attributed to the characteristic shape of the balls.

  1. Effect of polymer morphology on proton and water transport through ionomeric polymers. [Perfluorosulfonic ionomer

    Energy Technology Data Exchange (ETDEWEB)

    Fales, J.L.; Springer, T.E.; Vanderborgh, N.E.; Stroeve, P.

    1985-01-01

    The rate of ionic transport through perfluorosulfonic acid membranes is set by water content within mass transfer channels of the polymer. Consequently, control of water flux is important to control transport rates. Experiments show the influence of cation type on water transport properties and on polymer physical properties. These results support the model that channel geometries are determined by the interaction of coulombic forces within the membrane. Description of these transport processes is accomplished through several mathematical routes.

  2. Accuracy of the Water Vapour Content Measurements in the Atmosphere Using Optical Methods

    CERN Document Server

    Galkin, V D; Alekseeva, G A; Novikov, V V; Pakhomov, V P

    2010-01-01

    This paper describes the accuracy and the errors of water vapour content measurements in the atmosphere using optical methods, especially starphotometer. After the general explanations of the used expressions for the star-magnitude observations of the water vapour absorption in section 3 the absorption model for the water vapour band will be discussed. Sections 4 and 5 give an overview on the technique to determine the model parameters both from spectroscopic laboratory and radiosonde observation data. Finally, the sections 6 and 7 are dealing with the details of the errors; that means errors of observable magnitude, of instrumental extraterrestrial magnitude, of atmospheric extinction determination and of water vapour content determination by radiosonde humidity measurements. The main conclusion is: Because of the high precision of the results the optical methods for water vapour observation are suited to validate and calibrate alternative methods (GPS, LIDAR, MICROWAVE) which are making constant progress wo...

  3. Remote sensing of atmospheric water content from Bhaskara SAMIR data. [using statistical linear regression analysis

    Science.gov (United States)

    Gohil, B. S.; Hariharan, T. A.; Sharma, A. K.; Pandey, P. C.

    1982-01-01

    The 19.35 GHz and 22.235 GHz passive microwave radiometers (SAMIR) on board the Indian satellite Bhaskara have provided very useful data. From these data has been demonstrated the feasibility of deriving atmospheric and ocean surface parameters such as water vapor content, liquid water content, rainfall rate and ocean surface winds. Different approaches have been tried for deriving the atmospheric water content. The statistical and empirical methods have been used by others for the analysis of the Nimbus data. A simulation technique has been attempted for the first time for 19.35 GHz and 22.235 GHz radiometer data. The results obtained from three different methods are compared with radiosonde data. A case study of a tropical depression has been undertaken to demonstrate the capability of Bhaskara SAMIR data to show the variation of total water vapor and liquid water contents.

  4. Plant water-stress parameterization determines the strength of land-atmosphere coupling

    Science.gov (United States)

    Combe, Marie; Vilà-Guerau de Arellano, Jordi; Ouwersloot, Huug G.; Peters, Wouter

    2016-04-01

    Land-surface models that are currently used in numerical weather predictions models and earth system models all assume various plant water-stress parameterizations. We investigate the impact of this variety of parametrizations on the performance of atmospheric models. For this, we use a conceptual framework where a convective atmospheric boundary-layer (ABL) model is coupled to a daytime model for the land surface fluxes of carbon, water, and energy. We first validate our coupled model for a set of surface and upper-atmospheric diurnal observations over a grown maize field in the Netherlands. We then perform a sensitivity analysis of this coupled land-atmosphere system by varying the modeled plant water-stress response from a very insensitive to a sensitive response during dry soil conditions. We first propose and verify a feedback diagram that ties plant water-stress response and large-scale atmospheric conditions to the diurnal cycles of ABL CO2, humidity and temperature. Based on our undertanstanding of the diurnal coupled system, we then explore the impact of the assumed water-stress reponse for the development of a dry spell on a synoptic time scale. We find that during a progressive 3-week soil drying caused by evapotranspiration, an insensitive plant will dampen atmospheric heating because the vegetation continues to transpire while soil moisture is available. In contrast, the sensitive plant reduces its transpiration to prevent soil moisture depletion. But when absolute soil moisture comes close to wilting point, the insensitive plant will suddenly close its stomata causing a switch to a land-atmosphere coupling regime dominated by sensible heat exchange. We find that in both cases, our modeled progressive soil moisture depletion contributes to further atmospheric warming up to 6 K, reduced photosynthesis up to 89 %, and CO2 enrichment up to 30 ppm, but the full impact is strongly delayed for the insensitive plant. Finally, we demonstrate that the assumed

  5. Atmospheric transport, deposition, and fate of triazine herbicides and their metabolites in pristine areas at Isle Royale National Park

    Science.gov (United States)

    Thurman, E.M.; Cromwell, A.E.

    2000-01-01

    layer of the lakes increased during deposition periods and decreased later in the year. The fate of triazines in shallow lakes suggests faster degradation and shorter half-lives, while deeper lakes have residence times for atrazine that may exceed 10 years.Rainfall samples were collected at Isle Royale National Park, located in Lake Superior, and triazine herbicides were identified and quantified. Water samples were also collected from pristine lakes and analyzed for the presence of herbicides, and long-range atmospheric transport was determined using air-parcel, back-trajectory analysis. Results indicated that deposition was seasonal, with maximum concentrations occurring during the first week of June. Atrazine had the largest mass deposited on Isle Royal. Atrazine and deethylatrazine were the only herbicides detected in the surface-water samples. The annual mass of herbicides deposited by rainfall was calculated at 13.4, 3.7, and 54.0 ??g/m2, for 1992, 1993, and 1994, respectively. The source of the herbicides was attributed to Wisconsin, Minnesota, and Iowa, which are high-use areas for herbicides such as alachlor, atrazine, cyanazine, and metolachlor.

  6. Foliar Water Uptake of Tamarix ramosissima from an Atmosphere of High Humidity

    Directory of Open Access Journals (Sweden)

    Shuang Li

    2014-01-01

    Full Text Available Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants.

  7. The Role of Plant Water Storage on Water Fluxes within the Coupled Soil-Plant-Atmosphere System

    Science.gov (United States)

    Huang, C. W.; Duman, T.; Parolari, A.; Katul, G. G.

    2015-12-01

    Plant water storage (PWS) contributes to whole-plant transpiration (up to 50%), especially in large trees and during severe drought conditions. PWS also can impact water-carbon economy as well as the degree of resistance to drought. A 1-D porous media model is employed to accommodate transient water flow through the plant hydraulic system. This model provides a mechanistic representation of biophysical processes constraining water transport, accounting for plant hydraulic architecture and the nonlinear relation between stomatal aperture and leaf water potential when limited by soil water availability. Water transport within the vascular system from the stem base to the leaf-lamina is modeled using Richards's equation, parameterized with the hydraulic properties of the plant tissues. For simplicity, the conducting flow in the radial direction is not considered here and the capacitance at the leaf-lamina is assumed to be independent of leaf water potential. The water mass balance in the leaf lamina sets the upper boundary condition for the flow system, which links the leaf-level transpiration to the leaf water potential. Thus, the leaf-level gas exchange can be impacted by soil water availability through the water potential gradient from the leaf lamina to the soil, and vice versa. The root water uptake is modeled by a multi-layered macroscopic scheme to account for possible hydraulic redistribution (HR) in certain conditions. The main findings from the model calculations are that (1) HR can be diminished by the residual water potential gradient from roots to leaves at night due to aboveground capacitance, tree height, nocturnal transpiration or the combination of the three. The degree of reduction depends on the magnitude of residual water potential gradient; (2) nocturnal refilling to PWS elevates the leaf water potential that subsequently delays the onset of drought stress at the leaf; (3) Lifting water into the PWS instead of HR can be an advantageous strategy

  8. Application of Vacuum Swing Adsorption for Carbon Dioxide and Water Vapor Removal from Manned Spacecraft Atmospheres

    Science.gov (United States)

    Knox, J.; Fulda, P.; Howard, D.; Ritter, J.; Levan, M.

    2007-01-01

    The design and testing of a vacuum-swing adsorption process to remove metabolic 'water and carbon dioxide gases from NASA's Orion crew exploration vehicle atmosphere is presented. For the Orion spacecraft, the sorbent-based atmosphere revitalization (SBAR) system must remove all metabolic water, a technology approach 1Lhathas not been used in previous spacecraft life support systems. Design and testing of a prototype SBAR in sub-scale and full-scale configurations is discussed. Experimental and analytical investigations of dual-ended and single-ended vacuum desorption are presented. An experimental investigation of thermal linking between adsorbing and desorbing columns is also presented.

  9. Deposition of heavy water on soil and reemission to the atmosphere

    International Nuclear Information System (INIS)

    Field experiments using heavy water as a tracer instead of tritiated water (HTO) were carried out in November 1995 and August 1996 in Japan. The objective of these experiments was to estimate the behavior of HTO in the environment when HTO was released to the atmosphere. We measured the evolution of depth profiles of heavy water concentrations in soil water and compared the reemission rates with the evaporation velocities to study the deposition and reemission of heavy water to/from soil. The depth profiles of heavy water concentrations in soil were expressed by exponential functions of which the gradient depended on the deposition period. The initial reemission rates of heavy water from the soil were the highest, regardless of the meteorological conditions. The reemission occurred not only during the day but also at night, suggesting that the exchange of heavy water in the soil surface layer with H2O in air played a dominant role during nighttime. (orig.)

  10. Air pollutants and plant cuticles: mechanisms of gas and water transport, and effects on water permeability

    International Nuclear Information System (INIS)

    A short overview of studies carried out by K.J. Lendzian and his group on transport rates of pure pollutant gases across isolated cuticles will be given. They show that the boiling point of a gas is a good predictor of cuticular permeability. Apparently good prediction quality, however, contrasts with a considerable gap between uptake rates determined in stomata-free systems, and rates of dry deposition to whole leaves observed under conditions where stomata should be closed to the maximum extent. Apart from other possible reasons for this difference, examination of cuticular sorption and diffusion characteristics indicates two major problems that may account for inconsistencies to some extent: (1) transport rates of gases in cuticles may be concentration-dependent and (2) interactions in gas mixtures with respect to cuticular transport are possible. Potential mechanisms of transport across cuticles and ways of interaction between gases (including water vapour) will be discussed. There has long been the notion that air pollutants may affect the water barrier quality of plant cuticles. This hypothesis has been tested in a recent study of effects of a wide range of air pollutants and elevated UV-B radiation on adaxial in situ-cuticular water permeability of various broadleaf tree species. No effects were found unless the leaves showed visible signs of stress due to treatment or chamber effects. (orig.)

  11. Numerical analysis of coupled water transport in wood with a focus on the coupling parameter sorption

    DEFF Research Database (Denmark)

    Hozjan, T.; Turk, G.; Rodman, U.;

    2011-01-01

    This paper presents a study of sorption rate function in a so-called multi-Fickian or multi-phase model. This model describes the complex moisture transport system in wood, which consists of separate water-vapour and bound-water diffusion interacting through sorption. In the numerical example inf...... influence of the sorption rate function on water transport is presented. It can be seen that the sorption rate function has a noticeable influence on coupled water transport in wood....

  12. Atmospheric correction of SeaWiFS imagery for turbid coastal and inland waters

    Institute of Scientific and Technical Information of China (English)

    HE Xianqiang; PAN Delu; MAO Zhihua

    2004-01-01

    A practical algorithm of atmospheric correction for turbid coastal and inland waters is provided. The present algorithm uses the property that the water-leaving radiance at 412 nm increases very little with the increasing of water turbidity. Thus, in very turbid coastal and inland waters, the radiance at 412 nm can be used to estimate the aerosol scattering radiance at 865 nm. The performance of the new algorithm is validated with simulation for several cases. It is found that the retrieved remotely sensed reflectance is usually with error less than 10% for the first six bands of SeaWiFS. This new algorithm is also tested under various atmospheric conditions in the Changjiang River Estuary and the Hangzhou Bay where the sediment concentration is very high and the standard SeaWiFS atmospheric correction algorithm creates a mask due to atmospheric correction failure. The result proves the efficiency of this simple algorithm in reducing the errors of the water-leaving radiance retrieving using SeaWiFS satellite data.

  13. Validation of the atmospheric transport model: comparison of observed krypton-85 concentrations with those computed using a Gaussian plume model

    International Nuclear Information System (INIS)

    Thirty monthly average 85Kr concentrations measured at 13 sampling locations between 25 and 150 km from a quasi-continuous point source were used in a validation study of the Atmospheric Transport Model for Toxic Substances (ATM-TOX). Although the computed values tended to overestimate, more than 60% of them fell within a factor of 2 of the observed concentrations

  14. Assessing the Tangent Linear Behaviour of Common Tracer Transport Schemes and Their Use in a Linearised Atmospheric General Circulation Model

    Science.gov (United States)

    Holdaway, Daniel; Kent, James

    2015-01-01

    The linearity of a selection of common advection schemes is tested and examined with a view to their use in the tangent linear and adjoint versions of an atmospheric general circulation model. The schemes are tested within a simple offline one-dimensional periodic domain as well as using a simplified and complete configuration of the linearised version of NASA's Goddard Earth Observing System version 5 (GEOS-5). All schemes which prevent the development of negative values and preserve the shape of the solution are confirmed to have nonlinear behaviour. The piecewise parabolic method (PPM) with certain flux limiters, including that used by default in GEOS-5, is found to support linear growth near the shocks. This property can cause the rapid development of unrealistically large perturbations within the tangent linear and adjoint models. It is shown that these schemes with flux limiters should not be used within the linearised version of a transport scheme. The results from tests using GEOS-5 show that the current default scheme (a version of PPM) is not suitable for the tangent linear and adjoint model, and that using a linear third-order scheme for the linearised model produces better behaviour. Using the third-order scheme for the linearised model improves the correlations between the linear and non-linear perturbation trajectories for cloud liquid water and cloud liquid ice in GEOS-5.

  15. Complexes and clusters of water relevant to atmospheric chemistry: H2O complexes with oxidants.

    Science.gov (United States)

    Sennikov, Petr G; Ignatov, Stanislav K; Schrems, Otto

    2005-03-01

    Experimental observations and data from quantum chemical calculations on complexes between water molecules and small, oxygen-containing inorganic species that play an important role as oxidants in the atmosphere (O(1D), O(3P), O2(X3sigmag), O2(b1sigmag+), O3, HO, HOO, HOOO, and H2O2) are reviewed, with emphasis on their structure, hydrogen bonding, interaction energies, thermodynamic parameters, and infrared spectra. In recent years, weakly bound complexes containing water have increasingly attracted scientific attention. Water in all its phases is a major player in the absorption of solar and terrestrial radiation. Thus, complexes between water and other atmospheric species may have a perceivable influence on the radiative balance and contribute to the greenhouse effect, even though their concentrations are low. In addition, they can play an important role in the chemistry of the Earth's atmosphere, particularly in the oxidation of trace gases. Apart from gas-phase complexes, the interactions of oxidants with ice surfaces have also received considerable advertency lately due to their importance in the chemistry of snow, ice clouds, and ice surfaces (e.g., ice shields in polar regions). In paleoclimate--respectively paleoenvironmental--studies, it is essential to understand the transfer processes from the atmosphere to the ice surface. Consequently, special attention is being paid here to the intercomparison of the properties of binary complexes and the complexes and clusters of more complicated compositions, including oxidants adsorbed on ice surfaces, where ice is considered a kind of large water cluster. Various facts concerning the chemistry of the Earth's atmosphere (concentration profiles and possible influence on radical reactions in the atmosphere) are discussed. PMID:15799459

  16. Effects of atmospheric deposition of energy-related pollutants on water quality: a review and assessment

    International Nuclear Information System (INIS)

    The effects on surface-water quality of atmospheric pollutants that are generated during energy production are reviewed and evaluated. Atmospheric inputs from such sources to the aquatic environment may include trace elements, organic compounds, radionuclides, and acids. Combustion is the largest energy-related source of trace-element emissions to the atmosphere. This report reviews the nature of these emissions from coal-fired power plants and discusses their terrestrial and aquatic effects following deposition. Several simple models for lakes and streams are developed and are applied to assess the potential for adverse effects on surface-water quality of trace-element emissions from coal combustion. The probability of acute impacts on the aquatic environment appears to be low; however, more subtle, chronic effects are possible. The character of acid precipitation is reviewed, with emphasis on aquatic effects, and the nature of existing or potential effects on water quality, aquatic biota, and water supply is considered. The response of the aquatic environment to acid precipitation depends on the type of soils and bedrock in a watershed and the chemical characteristics of the water bodies in question. Methods for identifying regions sensitive to acid inputs are reviewed. The observed impact of acid precipitation ranges from no effects to elimination of fish populations. Coal-fired power plants and various stages of the nuclear fuel cycle release radionuclides to the atmosphere. Radioactive releases to the atmosphere from these sources and the possible aquatic effects of such releases are examined. For the nuclear fuel cycle, the major releases are from reactors and reprocessing. Although aquatic effects of atmospheric releases have not been fully quantified, there seems little reason for concern for man or aquatic biota

  17. Hydrological Modeling of Large Drainage Basins Using a GIS-based Hybrid Atmospheric and Terrestrial Water Balance (HATWAB) Model

    OpenAIRE

    Berhanu F. Alemaw

    2012-01-01

    A Hydrological model is proposed to study the spatial and temporal variability of the water budget components of large drainage basin systems from atmospheric and terrestrial water balances. In order to understand the water balances that include, surface runoff, actual evapotranspiration and soil moisture, a GIS-based simple water balance model which is referred as Hydrological Model from Hybrid Atmospheric and Terrestrial Water Balances with acronym HATWAB is presented. The spatio-temporal c...

  18. Parallelization and load balancing of a comprehensive atmospheric chemistry transport model

    Science.gov (United States)

    Elbern, Hendrik

    Chemistry transport models are generally claimed to be well suited for massively parallel processing on distributed memory architectures since the arithmetic-to-communication ratio is usually high. However, this observation proves insufficient to account for an efficient parallel performance with increasing complexity of the model. The modeling of the local state of the atmosphere ensues very different branches of the modules' code and greater differences in the computational work load and, consequently, runtime of individual processors occur to a much larger extent during a time step than reported for meteorological models. Variable emissions, changes in actinic fluxes, and all processes associated with cloud modeling are highly variable in time and space and are identified to induce large load imbalances which severely affect the parallel efficiency. This is more so, when the model domain encompasses more heterogeneous meteorological or regional regimes, which impinge dissimilarly on simulations of atmospheric chemistry processes. These conditions hold for the EURAD model applied in this study, which covers the European continental scale as integration domain. Based on a master-worker configuration with a horizontal grid partitioning approach, a method is proposed where the integration domain of the individual processors is locally adjusted to accommodate for load imbalances. This ensures a minimal communication volume and data exchange only with the next neighbors. The interior boundary adjustments of the processors are combined with routine boundary exchange which is required each time step anyway. Two dynamic load balancing schemes were implemented and compared against a conventional equal area partition and a static load balancing scheme. The methods are devised for massively parallel distributed memory computers of both, Single and Multiple Instruction stream Multiple Data stream (SIMD, MIMD) types. A midsummer episode of highly elevated ozone concentrations

  19. Preliminary results from the Los Alamos TA54 complex terrain Atmospheric Transport Study (ATS)

    Energy Technology Data Exchange (ETDEWEB)

    Vold, E.; Chan, M.; Sanders, L.

    1995-09-01

    The Los Alamos National Laboratory (LANL) Low-Level Radioactive Waste (LLRW) disposal site at TA54, Area G la located on a mesa top amidst a complex terrain of finger like mesas typically 30 motors or more In height above canyons of widths varying from 100 to 300 motors. Atmospheric dispersion from this site is of concern for routine operations and for potential Incidents during waste retrieval operations. Indian lands are located In the dominant downwind direction within 500 m from the site and provide further incentive to understand the potential and actual impacts of waste disposal operations. The permanent network of meteorological towers at LANL have been located primarily at mesa-top locations to coincide with most laboratory facilities and as such do not resolve the effects of channeling in the canyons and the influence this has on potential surface releases. An Atmospheric Transport Study (ATS) was initiated to better understand the wind flow fields and dispersion from the LANL Waste Storage and Disposal facilities at TA-54, Area G. As part of this effort, a series of six portable meteorological towers were sited in the vicinity of Area G, two at mesa top locations, one just east of the site where the mesas have dissipated to mild ridges, and three in the canyons adjacent to the disposal site mesa as indicated on the topographic representation of the local terrain. Since 1994, the towers have collected horizontal wind velocities, pressure, temperature, relative humidity and a radiation gamma reading every fifteen minutes. The data bass is being analyzed for trends and to provide a basis for comparison to computational modeling efforts to predict the flow fields.

  20. Atmospheric mercury deposition and its contribution of the regional atmospheric transport to mercury pollution at a national forest nature reserve, southwest China.

    Science.gov (United States)

    Ma, Ming; Wang, Dingyong; Du, Hongxia; Sun, Tao; Zhao, Zheng; Wei, Shiqing

    2015-12-01

    Atmospheric mercury deposition by wet and dry processes contributes to the transformation of mercury from atmosphere to terrestrial and aquatic systems. Factors influencing the amount of mercury deposited to subtropical forests were identified in this study. Throughfall and open field precipitation samples were collected in 2012 and 2013 using precipitation collectors from forest sites located across Mt. Jinyun in southwest China. Samples were collected approximately every 2 weeks and analyzed for total (THg) and methyl mercury (MeHg). Forest canopy was the primary factor on THg and MeHg deposition. Simultaneously, continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from March 2012 to February 2013 at the summit of Mt. Jinyun. Atmospheric GEM concentrations averaged 3.8 ± 1.5 ng m(-3), which was elevated compared with global background values. Sources identification indicated that both regional industrial emissions and long-range transport of Hg from central, northeast, and southwest China were corresponded to the elevated GEM levels. Precipitation deposition fluxes of THg and MeHg in Mt. Jinyun were slightly higher than those reported in Europe and North America, whereas total fluxes of MeHg and THg under forest canopy on Mt. Jiuyun were 3 and 2.9 times of the fluxes of THg in wet deposition in the open. Highly elevated litterfall deposition fluxes suggest that even in remote forest areas of China, deposition of atmospheric Hg(0) via uptake by vegetation leaf may be a major pathway for the deposition of atmospheric Hg. The result illustrates that areas with greater atmospheric pollution can be expected to have greater fluxes of Hg to soils via throughfall and litterfall. PMID:26298336

  1. Potential risk of microplastics transportation into ground water

    Science.gov (United States)

    Huerta, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A.; Geissen, Violette

    2016-04-01

    Microplastics, are plastics particles with a size smaller than 5mm. They are formed by the fragmentation of plastic wastes. They are present in the air, soil and water. But only in aquatic systems (ocean and rivers) are studies over their distribution, and the effect of microplastics on organisms. There is a lack of information of what is the distribution of microplastics in the soil, and in the ground water. This study tries to estimate the potential risk of microplastics transportation into the ground water by the activity of earthworms. Earthworms can produce burrows and/or galleries inside the soil, with the presence of earthworms some ecosystem services are enhanced, as infiltration. In this study we observed after 14 days with 5 treatments (0, 7, 28 and 60% w/w microplastics mixed with Populus nigra litter) and the anecic earthworm Lumbricus terrestris, in microcosms (3 replicas per treatment) that macroplastics are indeed deposit inside earthworms burrows, with 7% microplastics on the surface is possible to find 1.8 g.kg-1 microplastics inside the burrows, with a bioaumentation factor of 0.65. Burrows made by earthworms under 60% microplastics, are significant bigger (plitter that is deposit inside the burrows is significant higher (p<0.05) with the presence of microplastics on the surface than without microplastics. The microplastics size distribution is smaller inside the burrows than on the surface, with an abundance of particles under 63 μm.

  2. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    Science.gov (United States)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-ɛ) where ɛ is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values

  3. Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models

    Science.gov (United States)

    Loeb, Norman G.; Wang, Hailan; Cheng, Anning; Kato, Seiji; Fasullo, John T.; Xu, Kuan-Man; Allan, Richard P.

    2016-05-01

    Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHTEQ) and ocean (OHTEQ). The contrast in net atmospheric radiation implies an AHTEQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHTEQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHTEQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHTEQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHTEQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds.

  4. Movement of iodine and rain water from the atmosphere to the plant - soil - water system by the activable tracer techniques

    International Nuclear Information System (INIS)

    Iodine is one of the important elements in the environmental and agricultural sciences. It is requested to elucidate the long-term behavior of iodine in the atmosphere - soil·plant - soil water system. We developed the new tracer method, in which iodine released into the atmosphere from the stack of iodine manufacturing plant in Chiba prefecture was used as the activable tracer. Using this method, we traced the direct deposition of iodine in atmosphere onto the plant tops and the penetration of fallout iodine into soil in an open air over a long period. A quantitative evaluation of recharge function of water resources in agricultural and forest lands of Japan was eagerly requested from the nation. For it, we developed the new Br-tracer method combined with the soil water sampling system with the alumina porous ceramic cup. This tracer method was successfully applied to the agricultural and forest land in the catchment area of Sakawa river in Kanagawa prefecture. And the infiltration rate of the rain water and irrigation water, from the soil surface to the dept of 3m of the soil horizon in the forest land, tea garden and paddy field was quantitatively measured during two years. (J.P.N.)

  5. A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

    Directory of Open Access Journals (Sweden)

    Xi Xi

    2014-01-01

    Full Text Available Stable water isotopologues, mainly 1H2O, 1H2HO (HDO, and H12O18, are useful tracers for processes in the global hydrological cycle. The incorporation of water isotopes into Atmospheric General Circulation Models (AGCMs since 1984 has helped scientists gain substantial new insights into our present and past climate. In recent years, there have been several significant advances in water isotopes modeling in AGCMs. This paper reviews and synthesizes key advances accomplished in modeling (1 surface evaporation, (2 condensation, (3 supersaturation, (4 postcondensation processes, (5 vertical distribution of water isotopes, and (6 spatial δ18O-temperature slope and utilizing (1 spectral nudging technique, (2 higher model resolutions, and (3 coupled atmosphere-ocean models. It also reviews model validation through comparisons of model outputs and ground-based and spaceborne measurements. In the end, it identifies knowledge gaps and discusses future prospects of modeling and model validation.

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

    Directory of Open Access Journals (Sweden)

    C. Bassani

    2014-05-01

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

  7. Sensitivity study of land biosphere CO2 exchange through an atmospheric tracer transport model using satellite-derived vegetation index data

    International Nuclear Information System (INIS)

    We develop a simple, globally uniform model of CO2 exchange between the atmosphere and the terrestrial biosphere by coupling the model with a three-dimensional atmospheric tracer transport model using observed winds, and checking results against observed concentrations of CO2 at various monitoring sites. CO2 fluxes are derived from observed greenness using satellite-derived Global Vegetation Index data, combined with observations of temperature, radiation, and precipitation. We explore a range of CO2 flux formulations together with some modifications of the modelled atmospheric transport. We find that while some formulations can be excluded, it cannot be decided whether or not to make CO2 uptake and release dependent on water stress. It appears that the seasonality of net CO2 fluxes in the tropics, which would be expected to be driven by water availability, is small and is therefore not visible in the seasonal cycle of atmospheric CO2. The latter is dominated largely by northern temperate and boreal vegetation, where seasonality is mostly temperature determined. We find some evidence that there is still considerable CO2 release from soils during northern-hemisphere winter. An exponential air temperature dependence of soil release with a Q10 of 1.5 is found to be most appropriate, with no cutoff at low freezing temperatures. This result is independent of the year from which observed winds were taken. This is remarkable insofar as year-to-year changes in modelled CO2 concentrations caused by changes in the wind data clearly outweigh those caused by year-to-year variability in the climate and vegetation index data. (orig.)

  8. Filtered atmospheric venting of light water reactor containments

    International Nuclear Information System (INIS)

    The aim of filtered venting is to improve the function of the reactor containment in connection with very severe accidents. By equipping the containment with a safety valve for pressure relief and allowing the released gases to pass through an effective filter, it should be possible to achieve a considerable protective effect. The work has involved detailed studies of the core meltdown sequence, how the molten core material runs out of the reactor vessel, what effect it has on concrete and other structures and how final cooling of the molten core material takes place. On the basis of previous Swedish studies, the project has chosen to study a filter concept that consists of a gravel bed of large volume. This filter plant shall not only retain the radioactive particles that escape from the containment through the vent line, but shall also condense the accompanying steam. After the government decided in 1981 that Barsebaeck was to be equipped with filtered venting and issued specifications regarding its performance, the project aimed at obtaining results that could be used to design and verify a plant for filtered venting at the Barsebaeck nuclear power station. As far as the other Swedish nuclear power plants at Oskarshamn, Ringhals and Forsmark are concerned, the results are only applicable to a limited extent. Additional studies are required for these nuclear power plants before the value of filtered venting can be assessed. Based on the results of experiments and analyses, the project has made a safety analysis with Barsebaeck as a reference plant in order to study how the introduction of filtered venting affects the safety level at a station. In summary, the venting function appears to entail a not insignificant reduction of risks for boiling water reactors of the Barsebaeck type. For a number of types of such very severe core accident cases, the filter design studied ensures a substantial reduction of the releases. However it has not been possible within the

  9. Mesoscale Modeling of Water Vapor and Dust in Valles Marineris: Atmospheric Influences on Recurring Slope Lineae.

    Science.gov (United States)

    Leung, C. W. S.; Rafkin, S. C.; McEwen, A. S.

    2015-12-01

    Extensive recurring slope lineae (RSL) activity has been detected in Valles Marineris on Mars and coincides with regions where water ice fogs appear [1]. The origin of the water driving RSL flow is not well understood, but observational evidence suggests atmospheric processes play a crucial role [2]. Provided the atmospheric vapor concentration is high enough, water ice fogs can form overnight if the surface temperature cools below the condensation temperature. Correlations between dust storms and flow rates suggest that atmospheric dust opacity, and its influence on air temperature, also has a significant effect on RSL activity. We investigate planetary boundary layer processes that govern the hydrological cycle and dust cycle on Mars using a mesoscale atmospheric model to simulate the distribution of water and dust with respect to regional atmospheric circulations. Our simulations in Valles Marineris show a curious temperature structure, where the inside of the canyon appears warmer relative to the plateaus immediately outside. For a well-mixed atmosphere, this temperature structure indicates that when the atmosphere inside the canyon is saturated and fog is present within Valles Marineris, fog and low-lying clouds should also be present on the cooler surrounding plateaus as well. However, images taken with the Mars Express High Resolution Stereo Camera (HRSC) show instances where water ice fog appeared exclusively inside the canyon. These results have important implications for the origin and concentration of water vapor in Valles Marineris, with possible connections to RSL. The potential temperatures from our simulations show a high level of stability inside the canyon produced dynamically by sinking air. However, afternoon updrafts along the canyon walls indicate that over time, water vapor within the chasm would escape along the sides of the canyon. Again, this suggests a local source or mechanism to concentrate water vapor is needed to explain the fog

  10. Continental scale atmospheric and terrestrial water budget modeling and comparison to GRACE

    Science.gov (United States)

    Fersch, B.; Kunstmann, H.; Sneeuw, N.; Devaraju, B.

    2009-04-01

    Estimation of large scale water balances is still an unsolved challenge in hydrological sciences, particularly for data spare regions. The GRACE satellite mission (launched in 2002) provides a completely new opportunity to investigate seasonal large scale water mass changes based on measurements of gravitational acceleration differences. Our study aims at determining the potential of GRACE data for hydrological applications. Our approach assumes that vertically integrated atmospheric moisture convergence equals 1) precipitated minus evapotranspired water masses and therefore equals 2) aggregated surface runoff minus water storage changes. Using observed basin runoff, this interrelation allows us to compare GRACE derived water storage changes with modeled atmospheric moisture convergences. As regional atmospheric modeling is expected to yield more accurate meteorological fields than global model results, we use the WRF model for a dynamic downscaling of global atmospheric fields and hence derive high resolution fields of air pressure, horizontal moisture flux divergence, precipitation minus evapotranspiration, soil water storage, etc. Our study focuses on sensitivities and uncertainties of regionally modeled atmospheric mass and moisture fluxes due to specific model setup, origin of global driving data (NCEP vs. ECMWF) and spatial resolution. This is performed for four regions: Australia, Sahara, Siberia and the Amazon. The first three regions are characterized by a simplified hydrological mass balance, i.e. either evaporation or precipitation is close to zero. Central Australia represents a region with no outlet, meaning runoff is negligible. The Sahara also has zero runoff and for the dry periods evapotranspiration is close to zero. Siberia, comprising the catchments of Lena and Yenisei has negligible evapotranspiration for the winter months. The basin of the Amazon is representative for regions with high precipitation and evaporation terms. For the years 2003 to

  11. Water, solute and heat transport in the soil: the Australian connection

    Science.gov (United States)

    Knight, John

    2016-04-01

    The interest of Peter Raats in water, solute and heat transport in the soil has led to scientific and/or personal interactions with several Australian scientists such as John Philip, David Smiles, Greg Davis and John Knight. Along with John Philip and Robin Wooding, Peter was an early user of the Gardner (1958) linearised model of soil water flow, which brought him into competition with John Philip. I will discuss some of Peter's solutions relevant to infiltration from line and point sources, cavities and basins. A visit to Canberra, Australia in the early 1980s led to joint work on soil water flow, and on combined water and solute movement with David Smiles and others. In 1983 Peter was on the PhD committee for Greg Davis at the University of Wollongong, and some of the methods in his thesis 'Mathematical modelling of rate-limiting mechanisms of pyritic oxidation in overburden dumps' were later used by Peter's student Sjoerd van der Zee. David Smiles and Peter wrote a survey article 'Hydrology of swelling clay soils' in 2005. In the last decade Peter has been investigating the history of groundwater and vadose zone hydrology, and recently he and I have been bringing to light the largely forgotten work of Lewis Fry Richardson on finite difference solution of the heat equation, drainage theory, soil physics, and the soil-plant-atmosphere continuum.

  12. Evaluation of the atmospheric transport model NIRE-CTM-96 by using measured radon-222 concentrations

    International Nuclear Information System (INIS)

    An atmospheric transport model, NIRE-CTM-96, was evaluated by using measured radon-222 concentrations. The model has 2,5x2,5 degree horizontal resolution and 15 vertical levels. Assimilated global meteorological data for 1990-1996 from the European Centre for Medium Range Weather Forecasts were used to drive the model. We used an emanation rate of radon-222 of 1 atom/cm2/s over mostly ice-free land. Simulated concentrations were compared with measured concentrations for 22 sites worldwide including 10 stations in China. Simulated annual mean concentrations for Freiburg, Germany, and Socorro, New Mexico, and for four stations in northern China were consistent with the measured concentrations. Simulated daily concentrations for Ogasawara-Hahajima, Japan, correlated well with the measured concentrations. Simulated upper tropospheric concentrations for Moffet Field, California, demonstrated the cross-Pacific transport from central Eurasia and India-Indochina area. Simulated concentrations for two stations in southern China were almost half of the measured concentrations. Mixing layer depth in the model was consistent with other estimates which indicates higher emanation rate there. Simulated concentrations for the South Indian Ocean and the Antarctic during summer were significantly lower than the measured concentrations; this difference was accounted for when emanation from the ocean at a rate of 0.01 atom/cm2/s was included in the model. The model failed to simulate amplitudes of high-concentration events at Mauna Loa. These high-concentration events were possibly a result of filament-like horizontal structure or laminated vertical structure. The vertical as well as horizontal resolution of the model were supposed to be insufficient to reproduce these fine structures

  13. Long-range atmospheric transport and the distribution of polycyclic aromatic hydrocarbons in Changbai Mountain.

    Science.gov (United States)

    Zhao, Xiangai; Kim, Seung-Kyu; Zhu, Weihong; Kannan, Narayanan; Li, Donghao

    2015-01-01

    The Changbai (also known as "Baekdu") Mountain, on the border between China and North Korea, is the highest mountain (2750 m) in northeastern China. Recently, this mountain region has experienced a dramatic increase in air pollution, not only because of increasing volumes of tourism-derived traffic but also because of the long-range transport of polluted westerly winds passing through major industrial and urban cities in the eastern region of China. To assess the relative importance of the two sources of pollution, 16 polycyclic aromatic hydrocarbons (PAHs) as model substances were determined in the mountain soil. A total of 32 soil samples were collected from different sides of the mountain at different latitudes between July and August of 2009. The ∑PAH concentrations were within the range 38.5-190.1 ng g(-1) on the northern side, 117.7-443.6 ng g(-1) on the southern side, and 75.3-437.3 ng g(-1) on the western side. A progressive increase in the level of ∑PAHs with latitude was observed on the southern and western sides that face the westerly wind with abundant precipitation. However, a similar concentration gradient was not observed on the northern side that receives less rain and is on the leeward direction of the wind. The high-molecular-weight PAH compounds were predominant in the soils on the southern and western sides, while low-molecular-weight PAHs dominated the northern side soils. These findings show that the distribution of PAHs in the mountain soil is strongly influenced by the atmospheric long-range transport and cold trapping. PMID:25036943

  14. Response of the Adriatic Sea to an intense cold air outbreak: Dense water dynamics and wave-induced transport

    Science.gov (United States)

    Benetazzo, A.; Bergamasco, A.; Bonaldo, D.; Falcieri, F. M.; Sclavo, M.; Langone, L.; Carniel, S.

    2014-11-01

    The paper describes formation and spreading of dense shelf waters in the Adriatic Sea (North Adriatic Dense Water, NAdDW) during the winter of 2012 as a consequence of an intense and long cold air outbreak of northeasterly Bora winds. As a result, during February 2012 northern Adriatic Sea water temperature dropped to about 6 °C and density exceeded 1030 kg/m3, most likely the maximum value since 1929. NAdDW dynamics has been investigated by means of a 3-D ocean-wave coupled model running on a high resolution and eddy-permitting grid. The numerical experiments have relied on the Coupled-Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) system forced one-way with atmospheric forcings provided by the model COSMO-I7. A suite of observational data has been used to characterize the Bora event and evaluate numerical model performance. At sub-basin scales, the newly formed waters flowing southerly have produced a water renewal of the northern Adriatic, as more than 50% of water volumes have left the basin. Dense waters volume transports, evaluated through different Adriatic cross-sections, have been modulated by tides (damped for the densest water masses) and reached about 1 Sv. The contribution of wave-induced forcings has been quantified and examined, indicating that these represent a major driving mechanism during NAdDW production and spreading phases. This work provides evidence that NAdDW is spread accordingly with two different mechanisms: at early stages of its formation, the wind-driven ocean circulation pushes newly formed waters to leave the northern basin with relatively high speeds (about 0.30 m/s). Later on, remaining NAdDW leaks slowly out (0.09 m/s as average) from the production site. Residence times of dense waters in the north, middle, and south Adriatic Sea are also documented.

  15. Trajectory mapping of middle atmospheric water vapor by a mini network of NDACC instruments

    Directory of Open Access Journals (Sweden)

    M. Lainer

    2015-08-01

    Full Text Available The important task to observe the global coverage of middle atmospheric trace gases like water vapor or ozone usually is accomplished by satellites. Climate and atmospheric studies rely upon the knowledge of trace gas distributions throughout the stratosphere and mesosphere. Many of these gases are currently measured from satellites, but it is not clear whether this capability will be maintained in the future. This could lead to a significant knowledge gap of the state of the atmosphere. We explore the possibilities of mapping middle atmospheric water vapor in the Northern Hemisphere by using Lagrangian trajectory calculations and water vapor profile data from a small network of five ground-based microwave radiometers. Four of them are operated within the frame of NDACC (Network for the Detection of Atmospheric Composition Change. Keeping in mind that the instruments are based on different hardware and calibration setups, a height-dependent bias of the retrieved water vapor profiles has to be expected among the microwave radiometers. In order to correct and harmonize the different data sets, the Microwave Limb Sounder (MLS on the Aura satellite is used to serve as a kind of traveling standard. A domain-averaging TM (trajectory mapping method is applied which simplifies the subsequent validation of the quality of the trajectory-mapped water vapor distribution towards direct satellite observations. Trajectories are calculated forwards and backwards in time for up to 10 days using 6 hourly meteorological wind analysis fields. Overall, a total of four case studies of trajectory mapping in different meteorological regimes are discussed. One of the case studies takes place during a major sudden stratospheric warming (SSW accompanied by the polar vortex breakdown; a second takes place after the reformation of stable circulation system. TM cases close to the fall equinox and June solstice event from the year 2012 complete the study, showing the high

  16. Trajectory mapping of middle atmospheric water vapor by a mini network of NDACC instruments

    Directory of Open Access Journals (Sweden)

    M. Lainer

    2015-04-01

    Full Text Available The important task to observe the global coverage of middle atmospheric trace gases like water vapor or ozone usually is accomplished by satellites. Climate and atmospheric studies rely upon the knowledge of trace gas distributions throughout the stratosphere and mesosphere. Many of these gases are currently measured from satellites, but it is not clear whether this capability will be maintained in the future. This could lead to a significant knowledge gap of the state of the atmosphere. We explore the possibilities of mapping middle atmospheric water vapor in the Northern Hemisphere by using Lagrangian trajectory calculations and water vapor profile data from a small network of five ground-based microwave radiometers. Four of them are operated within the frame of NDACC (Network for the Detection of Atmospheric Composition Change. Keeping in mind that the instruments are based on different hardware and calibration setups, a height dependent bias of the retrieved water vapor profiles has to be expected among the microwave radiometers. In order to correct and harmonize the different datasets, the Microwave Limb Sounder (MLS on the Aura satellite is used to serve as a kind of travelling standard. A domain-averaging TM (trajectory mapping method is applied which simplifies the subsequent validation of the quality of the trajectory mapped water vapor distribution towards direct satellite observations. Trajectories are calculated forwards and backwards in time for up to 10 days using 6 hourly meteorological wind analysis fields. Overall, a total of four case studies of trajectory mapping in different meteorological regimes are discussed. One of the case studies takes place during a major sudden stratospheric warming (SSW accompanied by the polar vortex breakdown, a second takes place after the reformation of stable circulation system. TM cases close to the fall equinox and June solstice event from the year 2012 complete the study, showing the high

  17. Advanced InSAR atmospheric correction: MERIS/MODIS combination and stacked water vapour models

    OpenAIRE

    Z. Li; Fielding, E.; Cross, P; R. Preusker

    2009-01-01

    A major source of error for repeat-pass Interferometric Synthetic Aperture Radar (InSAR) is the phase delay in radio signal propagation through the atmosphere (especially the part due to tropospheric water vapour). Based on experience with the Global Positioning System (GPS)/Moderate Resolution Imaging Spectroradiometer (MODIS) integrated model and the Medium Resolution Imaging Spectrometer (MERIS) correction model, two new advanced InSAR water vapour correction models are demonstrated using ...

  18. Variability of winter-time middle atmospheric water vapour over the Arctic as observed with a ground-based microwave radiometer

    Science.gov (United States)

    Tschanz, Brigitte; Kivi, Rigel; Rüfenacht, Rolf; Kämpfer, Niklaus

    2014-05-01

    Middle atmospheric water vapour has a long chemical lifetime and can therefore be used as a tracer for dynamics. The ground-based microwave radiometer MIAWARA-C is designed for the use on campaigns and measures profiles of water vapour in the upper stratosphere and mesosphere and thus provides valuable data for the investigation of atmospheric processes. It has been operational for five years and has successfully participated in measurement campaigns under various climatic conditions in Germany, Switzerland, California, Finland and on la Réunion. The temporal resolution of the obtained water vapour profiles approximately 2 hours depending on tropospheric conditions. During two campaigns from January to June 2010 and from July 2011 to April 2013 in Sodankylä, Finland, MIAWARA-C monitored time series of polar middle atmospheric water vapour for three winters with three Sudden Stratospheric Warmings (SSW) occurring in early 2010, 2012 and 2013. The obtained time series are used to study the effects of the three SSWs on middle-atmospheric water vapour. During an SSW, humid mid- to low-latitude air is transported towards the polar region resulting in a fast increase in water vapour. The descent of water vapour after the SSW allows the estimation of the descent rate over the polar region as the normal wintertime circulation reforms. Results from the three SSWs are compared. The ground-based water vapour data is combined with sonde data of the Finnish Meteorological Institute and ground-based microwave wind measurements for one winter in order to obtain a more complete picture of the dynamics in the polar winter atmosphere.

  19. The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts

    Science.gov (United States)

    Vihma, Timo; Screen, James; Tjernström, Michael; Newton, Brandi; Zhang, Xiangdong; Popova, Valeria; Deser, Clara; Holland, Marika; Prowse, Terry

    2016-03-01

    Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.

  20. A Project on Atmospheric Water Generator with the Concept of Peltier Effect

    Directory of Open Access Journals (Sweden)

    Aditya Nandy

    2014-06-01

    Full Text Available In many countries like India it is difficult to obtain water resources for irrigation or other purposes, especially in the arid regions. The problem of water scarcity is also observed in other places of the world due to lack of rainfall. However, in highly humid areas such as places close to the sea, water can be obtained by condensing the water vapour present in air. Here, the paper presents the method to develop a water condensation system based on thermoelectric cooler. The system consists of cooling elements, heat exchange unit and air circulation unit. A solar cell panel unit with a relevant high current output drives the cooling elements through a controlling circuit. Atmospheric Water Generator is a device that can convert atmospheric moisture directly into usable and even drinkable water. It is such a device which uses the principle of latent heat to convert molecules of water vapour into water droplets. It has been introduced a bit before, though it is not very common in India and some other countries. It has a great application standing on such age of technology where we all are running behind renewable sources. This paper also describes the experimental results and the system’s performance.

  1. Carbon Dioxide in Exoplanetary Atmospheres: Rarely Dominant Compared to Carbon Monoxide and Water

    CERN Document Server

    Heng, Kevin

    2015-01-01

    We present a comprehensive study of the abundance of carbon dioxide in exoplanetary atmospheres. We construct analytical models of systems in chemical equilibrium that include carbon monoxide, carbon dioxide, water, methane and acetylene and relate the equilibrium constants of the chemical reactions to temperature and pressure via the tabulated Gibbs free energies. We prove that such chemical systems may be described by a quintic equation for the mixing ratio of methane. By examining the abundances of these molecules across a broad range of temperatures (spanning equilibrium temperatures from 600 to 2500 K), pressures (via temperature-pressure profiles that explore albedo and opacity variations) and carbon-to-oxygen ratios (from 0.1 to 100), we conclude that carbon dioxide is subdominant compared to carbon monoxide and water. Atmospheric mixing does not alter this conclusion if carbon dioxide is subdominant everywhere in the atmosphere. Carbon dioxide and carbon monoxide may attain comparable abundances if th...

  2. Water in planetary and cometary atmospheres: H2O/HDO transmittance and fluorescence models

    International Nuclear Information System (INIS)

    We developed a modern methodology to retrieve water (H2O) and deuterated water (HDO) in planetary and cometary atmospheres, and constructed an accurate spectral database that combines theoretical and empirical results. On the basis of a greatly expanded set of spectroscopic parameters, we built a full non-resonance cascade fluorescence model and computed fluorescence efficiencies for H2O (500 million lines) and HDO (700 million lines). The new line list was also integrated into an advanced terrestrial radiative transfer code (LBLRTM) and adapted to the CO2 rich atmosphere of Mars, for which we adopted the complex Robert-Bonamy formalism for line shapes. We retrieved water and D/H in the atmospheres of Mars, comet C/2007 W1 (Boattini), and Earth by applying the new formalism to spectra obtained with the high-resolution spectrograph NIRSPEC/Keck II atop Mauna Kea (Hawaii). The new model accurately describes the complex morphology of the water bands and greatly increases the accuracy of the retrieved abundances (and the D/H ratio in water) with respect to previously available models. The new model provides improved agreement of predicted and measured intensities for many H2O lines already identified in comets, and it identifies several unassigned cometary emission lines as new emission lines of H2O. The improved spectral accuracy permits retrieval of more accurate rotational temperatures and production rates for cometary water.

  3. Canopy-scale kinetic fractionation of atmospheric carbon dioxide and water vapour isotopes

    Science.gov (United States)

    The isotopic fluxes of carbon dioxide (CO2) and water vapour (H2O) between the atmosphere and terrestrial plants provide powerful constraints on carbon sequestration on land 1-2, changes in vegetation cover 3 and the Earth’s Dole effect 4. Past studies, relying mainly on leaf-scale observations, hav...

  4. Verification of the ASTER/TIR atmospheric correction algorithm based on water surface emissivity retrieved

    Science.gov (United States)

    Tonooka, Hideyuki; Palluconi, Frank D.

    2002-02-01

    The standard atmospheric correction algorithm for five thermal infrared (TIR) bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is currently based on radiative transfer computations with global assimilation data on a pixel-by-pixel basis. In the present paper, we verify this algorithm using 100 ASTER scenes globally acquired during the early mission period. In this verification, the max-min difference (MMD) of the water surface emissivity retrieved from each scene is used as an atmospheric correction error index, since the water surface emissivity is well known; if the MMD retrieved is large, an atmospheric correction error also will be possibly large. As the results, the error of the MMD retrieved by the standard atmospheric correction algorithm and a typical temperature/emissivity separation algorithm is shown to be remarkably related with precipitable water vapor, latitude, elevation, and surface temperature. It is also mentioned that the expected error on the MMD retrieved is 0.05 for the precipitable water vapor of 3 cm.

  5. Effects of water wave motion on pollutant transport in shallow coastal water

    Institute of Scientific and Technical Information of China (English)

    TAO; Jianhua(陶建华); HAN; Guang(韩光)

    2002-01-01

    Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic factor for pollutant transportation in the coastal water. Numerical simulation shows that the pollutant will transfer along shore when the incident wave is at an angle to the shoreline. This phenomenon is very significant if the outfall is located in the surfzone. Therefore, in the design of sea outfall, to improve near shore environment, the water wave should be considered as an important hydrodynamic factor.

  6. A review of approaches to estimate wildfire plume injection height within large scale atmospheric chemical transport models – Part 1

    Directory of Open Access Journals (Sweden)

    R. Paugam

    2015-03-01

    Full Text Available Landscape fires produce smoke containing a very wide variety of chemical species, both gases and aerosols. For larger, more intense fires that produce the greatest amounts of emissions per unit time, the smoke tends initially to be transported vertically or semi-vertically close by the source region, driven by the intense heat and convective energy released by the burning vegetation. The column of hot smoke rapidly entrains cooler ambient air, forming a rising plume within which the fire emissions are transported. This characteristics of this plume, and in particular the height to which it rises before releasing the majority of the smoke burden into the wider atmosphere, are important in terms of how the fire emissions are ultimately transported, since for example winds at different altitudes maybe quite different. This difference in atmospheric transport then may also affect the longevity, chemical conversion and fate of the plumes chemical consituents, with for example very high plume injection heights being associated with extreme long-range atmospheric transport. Here we review how such landscape-scale fire smoke plume injection heights are represented in larger scale atmospheric transport models aiming to represent the impacts of wildfire emissions on component of the Earth system. The use of satellite Earth observation (EO data is commonly used for this, and detail the EO datasets capable of being used to remotely assess wildfire plume height distributions and the driving characteristics of the causal fires. We also discus both the physical mechanisms and dynamics taking place in fire plumes, and investigate the efficiency and limitations of currently available injection height parameterizations. Finally, we conclude by suggestion some future parameterization developments and ideas on EO data selection that maybe relevant to the instigation of enhanced methodologies aimed at injection height representation.

  7. A review of approaches to estimate wildfire plume injection height within large-scale atmospheric chemical transport models

    Science.gov (United States)

    Paugam, R.; Wooster, M.; Freitas, S.; Martin, M. Val

    2016-01-01

    Landscape fires produce smoke containing a very wide variety of chemical species, both gases and aerosols. For larger, more intense fires that produce the greatest amounts of emissions per unit time, the smoke tends initially to be transported vertically or semi-vertically close by the source region, driven by the intense heat and convective energy released by the burning vegetation. The column of hot smoke rapidly entrains cooler ambient air, forming a rising plume within which the fire emissions are transported. The characteristics of this plume, and in particular the height to which it rises before releasing the majority of the smoke burden into the wider atmosphere, are important in terms of how the fire emissions are ultimately transported, since for example winds at different altitudes may be quite different. This difference in atmospheric transport then may also affect the longevity, chemical conversion, and fate of the plumes chemical constituents, with for example very high plume injection heights being associated with extreme long-range atmospheric transport. Here we review how such landscape-scale fire smoke plume injection heights are represented in larger-scale atmospheric transport models aiming to represent the impacts of wildfire emissions on component of the Earth system. In particular we detail (i) satellite Earth observation data sets capable of being used to remotely assess wildfire plume height distributions and (ii) the driving characteristics of the causal fires. We also discuss both the physical mechanisms and dynamics taking place in fire plumes and investigate the efficiency and limitations of currently available injection height parameterizations. Finally, we conclude by suggesting some future parameterization developments and ideas on Earth observation data selection that may be relevant to the instigation of enhanced methodologies aimed at injection height representation.

  8. FEMWATER BLT, Water or Waste Transport in Soil

    International Nuclear Information System (INIS)

    1 - Description of program or function: FEMWATER,BLT is used to model release and transport of contaminants from wastes stored in metallic containers in saturated or unsaturated soil systems including low- level waste disposal sites. Both programs provide two-dimensional, time-dependent, finite-element analyses. FEMWATER calculates water velocity, moisture content, and pressure head in unsaturated/ saturated porous media. BLT, a modification of the FEMWATER code, predicts container degradation, waste form leaching, and radionuclide migration in unsaturated porous media. 2 - Method of solution: FEMWATER and BLT perform two-dimensional time- dependent analyses using the finite element method. Nonlinearities in the unsaturated flow equations are handled through Picard iteration. The transport equations in BLT are linear, and Gaussian elimination is used to solve the matrix equations. 3 - Restrictions on the complexity of the problem - Maxima of: 528 finite elements (FEMWATER), 595 nodal points (FEMWATER), 225 finite elements (BLT), 252 nodal points (BLT), 100 waste-containing elements, 20 different waste types. These limits may be changed by re-dimensioning the appropriate arrays

  9. Experimental Study of Water Transport through Hydrophilic Nanochannels

    Science.gov (United States)

    Alibakhshi, Mohammad Amin; Xie, Quan; Li, Yinxiao; Duan, Chuanhua

    2015-11-01

    In this paper, we investigate one of the fundamental aspects of Nanofluidics, which is the experimental study of water transport through nanoscale hydrophilic conduits. A new method based on spontaneous filling and a novel hybrid nanochannel design is developed to measure the pure mass flow resistance of single nanofluidic channels/tubes. This method does not require any pressure and flow sensors and also does not rely on any theoretical estimations, holding the potential to be standards for nanofluidic flow characterization. We have used this method to measure the pure mass flow resistance of single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our experimental results quantify the increased mass flow resistance as a function of nanochannel height, showing a 45% increase for a 7nm channel compared with classical hydrodynamics, and suggest that the increased resistance is possibly due to formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. It has been further shown that this method can reliably measure a wide range of pure mass flow resistances of nanoscale conduits, and thus is promising for advancing studies of liquid transport in hydrophobic graphene nanochannels, CNTs, as well as nanoporous media. The work is supported by the American Chemical Society Petroleum Research Fund (ACS PRF # 54118-DNI7) and the Faculty Startup Fund (Boston University, USA).

  10. A simplified model for calculating atmospheric radionuclide transport and early health effects from nuclear reactor accidents

    International Nuclear Information System (INIS)

    During certain hypothetical severe accidents in a nuclear power plant, radionuclides could be released to the environment as a plume. Prediction of the atmospheric dispersion and transport of these radionuclides is important for assessment of the risk to the public from such accidents. A simplified PC-based model was developed that predicts time-integrated air concentration of each radionuclide at any location from release as a function of time integrated source strength using the Gaussian plume model. The solution procedure involves direct analytic integration of air concentration equations over time and position, using simplified meteorology. The formulation allows for dry and wet deposition, radioactive decay and daughter buildup, reactor building wake effects, the inversion lid effect, plume rise due to buoyancy or momentum, release duration, and grass height. Based on air and ground concentrations of the radionuclides, the early dose to an individual is calculated via cloudshine, groundshine, and inhalation. The model also calculates early health effects based on the doses. This paper presents aspects of the model that would be of interest to the prediction of environmental flows and their public consequences

  11. Dechloranes in lichens from the southeast Tibetan Plateau: Evidence of long-range atmospheric transport.

    Science.gov (United States)

    Yang, Ruiqiang; Zhang, Shujuan; Li, Xinghong; Luo, Dongxia; Jing, Chuanyong

    2016-02-01

    Dechloranes (Decs) have been recently found to occur widely in the environment even in the remote polar regions. However, the understanding of their environmental fate is rather limited. The Tibetan Plateau (TP) may be an important indicator region to study the long-range atmospheric transport and their fates of these emerging contaminants since it has very limited local sources. In the present study, Dechlorane plus (DP), Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603) and Dechlorane 604 (Dec 604) were analyzed in lichen samples from the southeast TP. The results showed that only DP and Dec 602 were detected, with a detection frequency of 89% and 100%, respectively. The average concentrations (dry weight) of ΣDP and Dec 602 were 318 pg g(-1) (20-1132 pg g(-1)) and 167 pg g(-1) (27-843 pg g(-1)), respectively. The DP concentration in this study was much higher than those in moss from the remote Ny-Ålesund, Arctic. The concentrations of Dec 602 were found to generally increase with increasing altitude, while DP concentrations seemingly showed an opposite altitudinal trend along the mountain slopes. No stereoselective accumulation or transformation of anti-DP and syn-DP was observed in lichens and the altitudinal behavior of the two isomers was similar. This research documented that Decs are prone to undergo LRAT and cold-trapping by the mountains in the southeast TP. PMID:26386769

  12. Integrated Assessment of Ecosystem Effects of Atmospheric Deposition

    Science.gov (United States)

    Ecosystems obtain a portion of their nutrients from the atmosphere. Following the Industrial Revolution, however, human