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Sample records for influence regional atmospheric

  1. Influence of Uncertainty in Atmospheric Transport Modeling on Regional and Continental Scale Inversions

    NASA Astrophysics Data System (ADS)

    Uliasz, M.; Schuh, A. E.

    2011-12-01

    Atmospheric transport modeling and its uncertainty play a crucial role in inversion studies with a goal to estimate fluxes of trace gases like carbon dioxide from available concentration measurements. Lagrangian particle models (e.g., CSU LPDM, STILT, FLEXPART) driven by regional meteorological models (e.g., WRF, RAMS) are state of the art tools in regional CO2 research including not only inversion studies, but also designing of tower network, or testing and supporting flight scenarios. They are typically used backward in time as an adjoint transport model providing, for each data point, influence functions (footprints) for surface fluxes and inflow fluxes across a domain perimeter. Modeling system used at CSU is based on SiB-RAMS (Regional Atmospheric Modeling System with Simple Biosphere model) providing meteorological fields for the LPDM (Lagrangian Particle Dispersion Model). Our LPDM can be run both in a forward and backward in time mode. Therefore, we recommend to use the comparison of forward and backward in time simulations as a method to evaluate internal model uncertainty. In addition the LPDM concentration fields can be compared to tracer concentrations simulated directly by RAMS, i.e. Eulerian grid model. We will discuss how simulated concentration fields, and in turn, the results of atmospheric inversions are affected by (1) model simplifications and optimizations, (2) time and space resolution of meteorological fields, and (3) selection of a domain for inversion study. The simulations are performed for the North America and smaller regional domains for a passive tracer and a tracers resulting from different CO2 fluxes (assimilation and respiration). Finally, we would like to propose a framework for inter comparison of different LPDMs coupled to regional meteorological models. This framework includes a sparse matrix format for influence functions to facilitate exchange and further applications of this product by different research groups.

  2. Influence of Atmospheric Solar Radiation Absorption on Photodestruction of Ions at D-Region Altitudes of the Ionosphere

    NASA Astrophysics Data System (ADS)

    Pavlov, A. V.

    2016-07-01

    The influence of atmospheric solar radiation absorption on the photodetachment, dissociative photodetachment, and photodissociation rate coefficients (photodestruction rate coefficients) of O-, Cl-, O2 -, O3 -, OH-, NO2 -, NO3 -, O4 -, OH-(H2O), CO3 -, CO4 -, ONOO-, HCO3 -, CO3 -(H2O), NO3 -(H2O), O2 +(H2O), O4 +, N4 +, NO+(H2O), NO+(H2O)2, H+(H2O) n for n = 2-4, NO+(N2), and NO+(CO2) at D-region altitudes of the ionosphere is studied. A numerical one-dimensional time-dependent neutral atmospheric composition model has been developed to estimate this influence. The model simulations are carried out for the geomagnetically quiet time period of 15 October 1998 at moderate solar activity over the Boulder ozonesonde. If the solar zenith angle is not more than 90° then the strongest influence of atmospheric solar radiation absorption on photodestruction of ions is found for photodissociation of CO4 - ions when CO3 - ions are formed. It follows from the calculations that decreases in the photodestruction rate coefficients of ions under consideration caused by this influence are less than 2 % at 70 km altitude and above this altitude if the solar zenith angle does not exceed 90°.

  3. Influence of atmospheric solar radiation absorption on photodestruction of ions at D-region altitudes of the ionosphere

    NASA Astrophysics Data System (ADS)

    Pavlov, Anatoli

    2016-07-01

    Influence of atmospheric solar radiation absorption on the photodetachment, dissociative photodetachment, and photodissociation rate coefficients (photodestruction rate coefficients) of O ^{-}, Cl ^{-}, O _{2} ^{-}, O _{3} ^{-}, OH ^{-}, NO _{2} ^{-}, NO _{3} ^{-}, O _{4} ^{-}, OH ^{-}(H _{2}O), CO _{3} ^{-}, CO _{4} ^{-}, ONOO ^{-}, HCO _{3} ^{-}, CO _{3} ^{-}(H _{2}O), NO _{3} ^{-}(H _{2}O), O _{2} ^{+}(H _{2}O), O _{4} ^{+}, N _{4} ^{+}, NO ^{+}(H _{2}O), NO ^{+}(H _{2}O) _{2}, H ^{+}(H _{2}O) _{n} for n=2-4, NO ^{+}(N _{2}), and NO ^{+}(CO _{2}) at D-region altitudes of the ionosphere is studied. A numerical one-dimensional time-dependent neutral atmospheric composition model has been developed to estimate this influence. The model simulations are carried out for the geomagnetically quiet time period of 15 October 1998 at moderate solar activity over the Boulder ozonesonde. If the solar zenith angle is not more than 90 ° then the most strongest influence of atmospheric solar radiation absorption on photodestruction of ions is found for photodissociation of CO _{4} ^{-} ions when CO _{3} ^{-} ions are formed. It follows from the calculations that decreases in the photodestruction rate coefficients of ions under consideration caused by this influence are less than 2 % at 70 km altitude and above this altitude if the solar zenith angle does not exceed 90 °.

  4. Influence of Large-scale Climate Modes on Atmospheric Rivers That Drive Regional Precipitation Extremes

    NASA Astrophysics Data System (ADS)

    Guan, B.; Molotch, N. P.; Waliser, D. E.; Fetzer, E. J.; Neiman, P. J.

    2014-12-01

    Atmospheric rivers (ARs) are narrow channels of enhanced meridional water vapor transport between the tropics and extratropics that drive precipitation extremes in the west coast areas of North America and other continents. The influence of large-scale climate modes on ARs is analyzed in terms of modulation on AR frequency and AR-related snow water equivalent (SWE) anomalies, with a focus on understanding the causes of the anomalously snowy winter season of 2010/2011 in California's Sierra Nevada. Mean SWE on 1 April 2011 was ~70% above normal averaged over 100 snow sensors. AR occurrence was anomalously high during the season, with 20 AR dates from November to March and 14 dates in the month of December 2010, compared to the mean occurrence of 9 dates per season. Most of the season's ARs occurred during negative phases of the Arctic Oscillation (AO) and the Pacific-North American (PNA) teleconnection pattern. Analysis of all winter ARs in California during water years 1998-2011 indicates more ARs occur during the negative phase of AO and PNA, with the increase between positive and negative phases being ~90% for AO, and ~50% for PNA. The circulation pattern associated with concurrent negative phases of AO and PNA, characterized by cyclonic anomalies centered northwest of California, provides a favorable dynamical condition for ARs. The analysis suggests that the massive Sierra Nevada snowpack during the 2010/2011 winter season is primarily related to anomalously high frequency of ARs favored by the joint phasing of -AO and -PNA, and that a secondary contribution is from increased snow accumulation during these ARs favored by colder air temperatures associated with -AO, -PNA and La Niña. The results have implications for subseasonal-to-seasonal predictability of AR activities and related weather and water extremes.

  5. Solar Terrestrial Influences on the D Region as Shown by the Level of Atmospheric Radio Noise

    NASA Technical Reports Server (NTRS)

    Satori, G.; Schaning, B.

    1984-01-01

    Measurements of the integrated atmospheric radio noise field strength at 27 kHz, used here, were made from 1965 to 1975 at Uppsala, Kuhlungsborn, and Prague-Panska Ves. The large scale meteorological situation was considered by comparing solar disturbed and undisturbed periods under similar weather situations. In order to show the effects of the precipitating high energy particle (HEP) flux and of the Forbush decrease on the noise level between pairs of stations were computed as deviations from the monthly median. Delta E (dB), day by day for all six periods was studied. The correlation coefficients for noon as well as for night values were computed. The correlation coefficients were compared with those for solar undisturbed periods.

  6. Processes for Identifying Regional Influences of and Responses to Increasing Atmospheric CO sub 2 and Climate Change --- The MINK Project

    SciTech Connect

    Easterling, W.E. III; McKenney, M.S.; Rosenberg, N.J.; Lemon, K.M.

    1991-08-01

    The second report of a series Processes for Identifying Regional Influences of and Responses to Increasing Atmospheric CO{sub 2} and Climate Change -- The MINK Project is composed of two parts. This Report (IIB) deals with agriculture at the level of farms and Major Land Resource Areas (MLRAs). The Erosion Productivity Impact Calculator (EPIC), a crop growth simulation model developed by scientists at the US Department of Agriculture, is used to study the impacts of the analog climate on yields of main crops in both the 1984/87 and the 2030 baselines. The results of this work with EPIC are the basis for the analysis of the climate change impacts on agriculture at the region-wide level undertaken in this report. Report IIA treats agriculture in MINK in terms of state and region-wide production and resource use for the main crops and animals in the baseline periods of 1984/87 and 2030. The effects of the analog climate on the industry at this level of aggregation are considered in both baseline periods. 41 refs., 40 figs., 46 tabs.

  7. Relative Influence of Trans-Pacific and Regional Atmospheric Transport of PAHs in the Pacific Northwest, U.S.

    PubMed

    Lafontaine, Scott; Schrlau, Jill; Butler, Jack; Jia, Yuling; Harper, Barbara; Harris, Stuart; Bramer, Lisa M; Waters, Katrina M; Harding, Anna; Simonich, Staci L Massey

    2015-12-01

    The relative influences of trans-Pacific and regional atmospheric transport on measured concentrations of polycyclic aromatic hydrocarbons (PAHs), PAH derivatives (nitro- (NPAH) and oxy-(OPAH)), organic carbon (OC), and particulate matter (PM) less than 2.5 μm in diameter (PM2.5) were investigated in the Pacific Northwest, U.S. in 2010-2011. Ambient high volume PM2.5 air samples were collected at two sites in the Pacific Northwest: (1.) Mount Bachelor Observatory (MBO) in the Oregon Cascade Range (2763 m above sea level (asl)) and 2.) Confederated Tribes of the Umatilla Indian Reservation (CTUIR) in the Columbia River Gorge (CRG) (954 m asl). At MBO, the 1,8-dinitropyrene concentration was significantly positively correlated with the time a sampled air mass spent over Asia, suggesting that this NPAH may be a good marker for trans-Pacific atmospheric transport. At CTUIR, NOx, CO2, and SO2 emissions from a 585 MW coal fired power plant, in Boardman OR, were found to be significantly positively correlated with PAH, OPAH, NPAH, OC, and PM2.5 concentrations. By comparing the Boardman Plant operational time frames when the plant was operating to when it was shut down, the plant was found to contribute a large percentage of the measured PAH (67%), NPAH (91%), OPAH (54%), PM2.5 (39%), and OC (38%) concentrations at CTUIR and the CRG prior to Spring 2011 and likely masked trans-Pacific atmospheric transport events to the CRG. Upgrades installed to the Boardman Plant in the spring of 2011 dramatically reduced the plant's contribution to PAH and OPAH concentrations (by ∼72% and ∼40%, respectively) at CTUIR and the CRG, but not NPAH, PM2.5 or OC concentrations. PMID:26151337

  8. Relative Influence of Trans-Pacific and Regional Atmospheric Transport of PAHs in the Pacific Northwest, U.S.

    PubMed Central

    2015-01-01

    The relative influences of trans-Pacific and regional atmospheric transport on measured concentrations of polycyclic aromatic hydrocarbons (PAHs), PAH derivatives (nitro- (NPAH) and oxy-(OPAH)), organic carbon (OC), and particulate matter (PM) less than 2.5 μm in diameter (PM2.5) were investigated in the Pacific Northwest, U.S. in 2010–2011. Ambient high volume PM2.5 air samples were collected at two sites in the Pacific Northwest: (1.) Mount Bachelor Observatory (MBO) in the Oregon Cascade Range (2763 m above sea level (asl)) and 2.) Confederated Tribes of the Umatilla Indian Reservation (CTUIR) in the Columbia River Gorge (CRG) (954 m asl). At MBO, the 1,8-dinitropyrene concentration was significantly positively correlated with the time a sampled air mass spent over Asia, suggesting that this NPAH may be a good marker for trans-Pacific atmospheric transport. At CTUIR, NOx, CO2, and SO2 emissions from a 585 MW coal fired power plant, in Boardman OR, were found to be significantly positively correlated with PAH, OPAH, NPAH, OC, and PM2.5 concentrations. By comparing the Boardman Plant operational time frames when the plant was operating to when it was shut down, the plant was found to contribute a large percentage of the measured PAH (67%), NPAH (91%), OPAH (54%), PM2.5 (39%), and OC (38%) concentrations at CTUIR and the CRG prior to Spring 2011 and likely masked trans-Pacific atmospheric transport events to the CRG. Upgrades installed to the Boardman Plant in the spring of 2011 dramatically reduced the plant’s contribution to PAH and OPAH concentrations (by ∼72% and ∼40%, respectively) at CTUIR and the CRG, but not NPAH, PM2.5 or OC concentrations. PMID:26151337

  9. The effect of regional-scale soil-moisture deficits on mesoscale atmospheric dynamics that influence fire severity

    SciTech Connect

    Fast, J.D.

    1994-09-30

    This study employs a three-dimensional, nonhydrostatic mesoscale model to evaluate the effects of horizontally heterogeneous soil moisture and vegetation type on the atmosphere during two periods in which wildland fires occurred. Numerical sensitivity simulations demonstrate that evapotranspiration significantly affects the boundary-layer structure embedded in the synoptic-scale circulations. In regions with sufficiently moist soils, evapotranspiration increases the humidity and modifies the diurnally varying temperature near the surface. Occasionally, changes in the humidity and temperature fields can also be seen a significant distance downwind of the moist soil regions. The perturbations in the temperature fields ultimately affect the wind speed and direction over or at the boundaries of the moist-soil regions, but only at certain times during the simulation period. The higher humidity also increases the cloudiness and changes the precipitation amounts, indicating that soil moisture and vegetation may play an important role in modifying the spatial distribution and intensity of precipitation. A lower atmospheric stability index, that is an indicator of the potential for wildland fire, is also calculated from the model results. This index is also sensitive to the horizontal distribution of soil moisture and vegetation, especially in regions with relatively moist soils. While only two periods are examined in this study, the impact of surface inhomogeneities in soil moisture and vegetation type on the atmosphere is expected to be highly dependent on the particular synoptic conditions and upon the distribution of soil moisture.

  10. Possible influence of atmospheric circulations on winter haze pollution in the Beijing-Tianjin-Hebei region, northern China

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Zhang, X.; Gong, D.; Kim, S.-J.; Mao, R.; Zhao, X.

    2016-01-01

    Using the daily records derived from the synoptic weather stations and the NCEP/NCAR and ERA-Interim reanalysis data, the variability of the winter haze pollution (indicated by the mean visibility and number of hazy days) in the Beijing-Tianjin-Hebei (BTH) region during the period 1981 to 2015 and its relationship with the atmospheric circulations at middle-high latitude were analyzed in this study. The winter haze pollution in BTH had distinct inter-annual and inter-decadal variabilities without a significant long-term trend. According to the spatial distribution of correlation coefficients, six atmospheric circulation indices (I1 to I6) were defined from the key areas in sea level pressure (SLP), zonal and meridional winds at 850 hPa (U850, V850), geopotential height field at 500 hPa (H500), zonal wind at 200 hPa (U200), and air temperature at 200 hPa (T200), respectively. All of the six indices have significant and stable correlations with the winter visibility and number of hazy days in BTH. In the raw (unfiltered) correlations, the correlation coefficients between the six indices and the winter visibility (number of hazy days) varied from 0.57 (0.47) to 0.76 (0.6) with an average of 0.65 (0.54); in the high-frequency ( < 10 years) correlations, the coefficients varied from 0.62 (0.58) to 0.8 (0.69) with an average of 0.69 (0.64). The six circulation indices together can explain 77.7 % (78.7 %) and 61.7 % (69.1 %) variances of the winter visibility and the number of hazy days in the year-to-year (inter-annual) variability, respectively. The increase in Ic (a comprehensive index derived from the six individual circulation indices) can cause a shallowing of the East Asian trough at the middle troposphere and a weakening of the Siberian high-pressure field at sea level, and is then accompanied by a reduction (increase) of horizontal advection and vertical convection (relative humidity) in the lowest troposphere and a reduced boundary layer height in BTH and its

  11. Regional Biases in Droplet Activation Parameterizations: Strong Influence on Aerosol Second Indirect Effect in the Community Atmosphere Model v5.

    NASA Astrophysics Data System (ADS)

    Morales, R.; Nenes, A.

    2014-12-01

    Aerosol-cloud interactions constitute one of the most uncertain aspects of anthropogenic climate change estimates. The magnitude of these interactions as represented in climate models strongly depends on the process of aerosol activation. This process is the most direct physical link between aerosols and cloud microphysical properties. Calculation of droplet number in GCMs requires the computation of new droplet formation (i.e., droplet activation), through physically based activation parameterizations. Considerable effort has been placed in ensuring that droplet activation parameterizations have a physically consistent response to changes in aerosol number concentration. However, recent analyses using an adjoint sensitivity approach showed that parameterizations can exhibit considerable biases in their response to other aerosol properties, such as aerosol modal diameter or to the aerosol chemical composition. This is a potentially important factor in estimating aerosol indirect effects since changes in aerosol properties from pre-industrial times to present day exhibit a very strong regional signature. In this work we use the Community Atmosphere Model (CAM5) to show that the regional imprint of the changes in aerosol properties during the last century interacts with the droplet activation parameterization in a way that these biases are amplified over climatically relevant regions. Two commonly used activation routines, the CAM5 default, Abdul-Razzak and Ghan parameterization, as well as the Fountoukis and Nenes parameterization are used in this study. We further explored the impacts of Nd parameterization biases in the first and second aerosol indirect effects separately, by performing simulations were droplet number was not allowed to intervene in the precipitation initiation process. The simulations performed show that an unphysical response to changes in the diameter of accumulation mode aerosol translates into extremely high Nd concentrations over South

  12. Atmospheric composition - Influence of biology

    NASA Technical Reports Server (NTRS)

    Mcelroy, M. B.

    1983-01-01

    The variability of atmospheric constituents influenced by biological organisms over various time scales is examined, together with the human contribution to atmospheric sulfur. The biogeochemistry of nitrogen is discussed, with an emphasis on N2O, NO, and microbially mediated reactions in soil and water. Carbon species are bound up mainly in sediments and the deep ocean, but human activities involving combustion may cause a doubling of the atmospheric levels of CO2 in the near future, which could produce a general low-level atmospheric warming. Longer term measurements are required to assess the effects of CH4 augmentation in the atmosphere through fuel combustion. Coal burning effectively doubles the amount of SO2 produced by natural sources, and reduces the pH of rainwater, thus posing hazards to fish, plankton, and mollusc life.

  13. Regional Ecosystem-Atmosphere CO2 Exchange Via Atmospheric Budgets

    SciTech Connect

    Davis, K J; Richardson, S J; Miles, N L

    2007-03-07

    are captured. Influence functions, derived using a Lagrangian Particle Dispersion model driven by the CSU Regional Atmospheric Modeling System and nudged to NCEP reanalysis meteorological fields, are used to determine source regions for the towers. The influence functions are combined with satellite vegetation observations to interpret the observed trends in CO2 concentration. Full inversions will combine these elements in a more formal analytic framework.

  14. Experimental evaluation of atmospheric aerosol turbidity in different Atlantic regions

    SciTech Connect

    Plakhina, I.N.; Pyrogov, S.M.

    1994-12-31

    The statistical estimation of the experimental values of atmospheric turbidity are considered over the different Atlantic regions: from clean atmospheric conditions to very turbid conditions influenced by air masses from Africa containing continental Sahara aerosol. The factors influencing the variability of atmospheric turbidity are also analyzed. The contribution of aerosol to atmospheric attenuation of the direct solar radiation is estimated. It is shown that aerosol is the main factor determining the values of the optical thickness and its variability. The single scattering albedo is evaluated. The influence of the Sahara dust on the total solar radiation over the ocean surface is estimated. Based on the found relationship between aerosol optical thickness, total atmosphere, and aerosol turbidity in the surface layer, the height of the homogeneous atmosphere has been estimated. In addition, the aerosol generation by ocean surface in storm conditions has been considered.

  15. Influence of runoff, high frequency atmospheric forcing and model resolution on deep water mass formation regions and Atlantic Meridional Overturning Circulation, from a numerical model.

    NASA Astrophysics Data System (ADS)

    Garcia Quintana, Yarisbel; Courtois, Peggy; Hu, Xianmin; Pennelly, Clark; Myers, Paul G.

    2016-04-01

    Water mass formation regions act as windows to the deep ocean where surface waters are transformed to intermediate and deep waters. Within the North Atlantic, Labrador Sea Water (LSW) is convectively produced in the Labrador Sea while in the Nordic Seas the source waters for Denmark Strait Overflow Water (DSOW) and Iceland-Scotland Overflow Water (NEADW) are formed. They are the main components of the North Atlantic Deep Water (NADW) which forms the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). We explore the changes of the LSW formation rates and in AMOC strength as consequence of runoff glacial melt, high frequency atmospheric forcing influence and variations in model's resolution. We use 1/4° resolution Arctic and Northern Hemisphere Atlantic (ANHA4) configuration from the Nucleus for European Modelling of the Ocean (NEMO) model. A nest using ANHA4 and the Adaptive Grid Refinement in FORTRAN (AGRIF) package was used to increase the resolution to 1/12° in the sub-polar gyre. The formation rate is calculated based upon a kinematic subduction approach where the exchange through the dynamic mixed layer base is calculated based on shallowing and deepening in the mixed layer, and convergence of horizontal transport into or out of the mixed layer. Lastly we use a Lagrangian tool (Ariane) to track the path of the DSOW and the NEADW from their formation source.

  16. [Atmospheric Influences Analysis on the Satellite Passive Microwave Remote Sensing].

    PubMed

    Qiu, Yu-bao; Shi, Li-juan; Shi, Jian-cheng; Zhao, Shao-jie

    2016-02-01

    Passive microwave remote sensing offers its all-weather work capabilities, but atmospheric influences on satellite microwave brightness temperature were different under different atmospheric conditions and environments. In order to clarify atmospheric influences on Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), atmospheric radiation were simulated based on AMSR-E configuration under clear sky and cloudy conditions, by using radiative transfer model and atmospheric conditions data. Results showed that atmospheric water vapor was the major factor for atmospheric radiation under clear sky condition. Atmospheric transmittances were almost above 0.98 at AMSR-E's low frequencies (< 18.7 GHz) and the microwave brightness temperature changes caused by atmosphere can be ignored in clear sky condition. Atmospheric transmittances at 36.5 and 89 GHz were 0.896 and 0.756 respectively. The effects of atmospheric water vapor needed to be corrected when using microwave high-frequency channels to inverse land surface parameters in clear sky condition. But under cloud cover or cloudy conditions, cloud liquid water was the key factor to cause atmospheric radiation. When sky was covered by typical stratus cloud, atmospheric transmittances at 10.7, 18.7 and 36.5 GHz were 0.942, 0.828 and 0.605 respectively. Comparing with the clear sky condition, the down-welling atmospheric radiation caused by cloud liquid water increased up to 75.365 K at 36.5 GHz. It showed that the atmospheric correction under different clouds covered condition was the primary work to improve the accuracy of land surface parameters inversion of passive microwave remote sensing. The results also provided the basis for microwave atmospheric correction algorithm development. Finally, the atmospheric sounding data was utilized to calculate the atmospheric transmittance of Hailaer Region, Inner Mongolia province, in July 2013. The results indicated that atmospheric transmittances were close to 1

  17. [Atmospheric Influences Analysis on the Satellite Passive Microwave Remote Sensing].

    PubMed

    Qiu, Yu-bao; Shi, Li-juan; Shi, Jian-cheng; Zhao, Shao-jie

    2016-02-01

    Passive microwave remote sensing offers its all-weather work capabilities, but atmospheric influences on satellite microwave brightness temperature were different under different atmospheric conditions and environments. In order to clarify atmospheric influences on Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), atmospheric radiation were simulated based on AMSR-E configuration under clear sky and cloudy conditions, by using radiative transfer model and atmospheric conditions data. Results showed that atmospheric water vapor was the major factor for atmospheric radiation under clear sky condition. Atmospheric transmittances were almost above 0.98 at AMSR-E's low frequencies (< 18.7 GHz) and the microwave brightness temperature changes caused by atmosphere can be ignored in clear sky condition. Atmospheric transmittances at 36.5 and 89 GHz were 0.896 and 0.756 respectively. The effects of atmospheric water vapor needed to be corrected when using microwave high-frequency channels to inverse land surface parameters in clear sky condition. But under cloud cover or cloudy conditions, cloud liquid water was the key factor to cause atmospheric radiation. When sky was covered by typical stratus cloud, atmospheric transmittances at 10.7, 18.7 and 36.5 GHz were 0.942, 0.828 and 0.605 respectively. Comparing with the clear sky condition, the down-welling atmospheric radiation caused by cloud liquid water increased up to 75.365 K at 36.5 GHz. It showed that the atmospheric correction under different clouds covered condition was the primary work to improve the accuracy of land surface parameters inversion of passive microwave remote sensing. The results also provided the basis for microwave atmospheric correction algorithm development. Finally, the atmospheric sounding data was utilized to calculate the atmospheric transmittance of Hailaer Region, Inner Mongolia province, in July 2013. The results indicated that atmospheric transmittances were close to 1

  18. Energetic particle influences in Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Harrison, R. Giles; Nicoll, Keri; Rycroft, Michael; Briggs, Aaron

    2016-04-01

    Energetic particles from outer space, known as galactic cosmic rays, constantly ionise the entire atmosphere. During strong solar storms, solar energetic particles can also reach the troposphere and enhance ionisation. Atmospheric ionisation generates cluster ions. These facilitate current flow in the global electric circuit, which arises from charge separation in thunderstorms driven by meteorological processes. Energetic particles, whether solar or galactic in origin, may influence the troposphere and stratosphere through a range of different mechanisms, each probably contributing a small amount. Some of the suggested processes potentially acting over a wide spatial area in the troposphere include enhanced scavenging of charged aerosol particles, modification of droplet or droplet-droplet behavior by charging, and the direct absorption of infra-red radiation by the bending and stretching of hydrogen bonds inside atmospheric cluster-ions. As well as reviewing the proposed mechanisms by which energetic particles modulate atmospheric properties, we will also discuss new instrumentation for measurement of energetic particles in the atmosphere.

  19. Processes for identifying regional influences of and responses to increasing atmospheric CO{sub 2} and climate change - the MINK project: An overview

    SciTech Connect

    Rosenberg, N.J.; Crosson, P.R.

    1991-08-01

    Scientists believe that a serious change in the climate of the earth could occur in the course of the next two to five decades as a result of warming caused by the rapid accumulation of radiatively active trace gases in the atmosphere. There is concern that not only the amount of warming but the rate at which it occurs could be unprecedented, at least since the current interglacial period began. Scientific uncertainties remain in our understanding of the climatic changes that may follow from greenhouse warming. Nevertheless, large and rapid changes in regional climate are conceivable. General circulation models (GCMs) predict changes for the central U.S. as large as an 8{degrees}C increase in mean summertime temperature accompanied by a 1 mm/day decrease in mean precipitation. Most predictions are less extreme but, so long as the direction of change is credible, efforts are warranted to identify just what kinds of impacts to expect if society chooses to allow climate to change or cannot stop it from changing, and just what might be done to adjust to those impacts.

  20. Atmospheric influence of Earth's earliest sulfur cycle

    PubMed

    Farquhar; Bao; Thiemens

    2000-08-01

    Mass-independent isotopic signatures for delta(33)S, delta(34)S, and delta(36)S from sulfide and sulfate in Precambrian rocks indicate that a change occurred in the sulfur cycle between 2090 and 2450 million years ago (Ma). Before 2450 Ma, the cycle was influenced by gas-phase atmospheric reactions. These atmospheric reactions also played a role in determining the oxidation state of sulfur, implying that atmospheric oxygen partial pressures were low and that the roles of oxidative weathering and of microbial oxidation and reduction of sulfur were minimal. Atmospheric fractionation processes should be considered in the use of sulfur isotopes to study the onset and consequences of microbial fractionation processes in Earth's early history.

  1. Exploring the influence of surface waves in the carbon dioxide transfer velocity between the ocean and atmosphere in the coastal region

    NASA Astrophysics Data System (ADS)

    Ocampo-Torres, Francisco Javier; Francisco Herrera, Carlos; Gutiérrez-Loza, Lucía; Osuna, Pedro

    2016-04-01

    Field measurements have been carried out in order to better understand the possible influence of ocean surface waves in the transfer of carbon dioxide between the ocean and atmosphere in the coastal zone. The CO2 fluxes are being analysed and results are shown in a contribution by Gutiérrez-Loza et al., in this session. Here we try to highlight the findings regarding the transfer velocity (kCO2) once we have incorporated direct measurements of carbon dioxide concentration in the water side. In this study direct measurements of CO2 fluxes were obtained with an eddy covariance tower located in the shoreline equipped with an infrared open-path gas analyzer (LI-7500, LI-COR) and a sonic anemometer (R3-100 Professional Anemometer, Gill Instruments), both at about 13 m above the mean sea level, and sampling at 20 Hz. For some period of time simultaneous information of waves was recorded with a sampling rate of 2 Hz using an Acoustic Doppler Current Profiler (Workhorse Sentinel, Teledyne RD Instruments) at 10 m depth and 350 m away from the tower. Besides, recently the concentration of CO2 in water has also been recorded making use of a SAMI-CO2 instrument. A subtle effect of the wave field is detected in the estimated kCO2. Looking into details of the surface currents being detected very near the air-sea interface through an ADPC, a certain association can be found with the gas transfer velocity. Furthermore, some of the possible effects of breaking wave induced turbulence in the coastal zone is to be addressed. This work represents a RugDiSMar Project (CONACYT 155793) contribution. The support from CB-2011-01-168173 CONACYT project is greatly acknowledged.

  2. Influence of geomagnetic disturbance on atmospheric circulation

    NASA Technical Reports Server (NTRS)

    Kodera, K.

    1985-01-01

    The influence of geomagnetic disturbance or passage of the solar sector boundary on the atmospheric circulation was reported. Unfortunately little is known about the general morphology of Sun weather relationships. In order to know the general characteristics, pressure height variations on an isobaric surface over the Northern Hemisphere were analyzed. Although it may be suitable to use some index, or some integrated value for statistical purposes, weather prediction data were used to verify whether the obtained tropospheric response is caused externally or not.

  3. Direct and Indirect ENSO Influences on Regional Climate

    NASA Astrophysics Data System (ADS)

    Wu, Renguang

    2016-04-01

    El Niño-Southern Oscillation (ENSO) is one of the strongest signals in the tropics and imposes large influences on climate in many regions, such as the Indian summer monsoon, central American precipitation, and the South China Sea precipitation. ENSO affects regional climate variability both directly and indirectly. The direct influence is through concurrent atmospheric circulation response to anomalous heating associated with equatorial central and eastern Pacific SST anomalies. The indirect influence is by first inducing regional SST anomalies through the so-called "atmospheric bridge" and then atmospheric circulation response to the regional SST anomalies. Previous studies are either focused on the direct influence of ENSO via concurrent atmospheric change or the indirect influence of ENSO via regional SST anomalies. In this talk, the presenter will distinguish the direct and indirect influences of ENSO and demonstrate how the two types of influences may play together in leading to regional climate variability. Summer climate anomalies in three regions will be used for illustration: the Indian summer monsoon, central American summer precipitation, and the South China Sea summer precipitation.

  4. Global and regional environmental atmospheric chemistry

    SciTech Connect

    Newman, L. ); Wang, Wenxing ); Kiang, C.S. . Div. of Atmospheric Science)

    1990-08-01

    More than two hundred fifty scientists from eighteen different countries attended the first International Conference on Global and Regional Environmental Atmospheric Chemistry in the Science Hall of Friendship Hotel at Beijing, May 3--10, 1989. This volume documents the proceedings of this historical event. Following the meeting, some 173 papers were submitted for this publication. When follow up papers were not submitted the original abstract is presented. Also included are abstracts of the posters presented by the Chinese participants who could not be accommodated during the more formal sessions. We might add that this more informal session was particularly useful for the exchange of ideas and information between east and west. Indeed, the conference overall certainly provided an enthusiastic platform for interactions among scientists from around the world. It is our hope that these proceedings will serve as a vehicle to further enhance collaboration for joint studies of the changes in the global environment.

  5. [Regional atmospheric environment risk source identification and assessment].

    PubMed

    Zhang, Xiao-Chun; Chen, Wei-Ping; Ma, Chun; Zhan, Shui-Fen; Jiao, Wen-Tao

    2012-12-01

    Identification and assessment for atmospheric environment risk source plays an important role in regional atmospheric risk assessment and regional atmospheric pollution prevention and control. The likelihood exposure and consequence assessment method (LEC method) and the Delphi method were employed to build a fast and effective method for identification and assessment of regional atmospheric environment risk sources. This method was applied to the case study of a large coal transportation port in North China. The assessment results showed that the risk characteristics and the harm degree of regional atmospheric environment risk source were in line with the actual situation. Fast and effective identification and assessment of risk source has laid an important foundation for the regional atmospheric environmental risk assessment and regional atmospheric pollution prevention and control.

  6. Influence of atmospheric forcing parameters on land surface simulation

    NASA Astrophysics Data System (ADS)

    Nayak, H. P.; Mandal, M.; Bhattacharya, A.

    2015-12-01

    The quality of atmospheric forcing plays important role on land surface simulation using decoupled land surface modeling system. In the present study, the influence of the various atmospheric forcing parameters on land surface simulation is assessed through sensitivity experiments. Numerical experiments are conducted towards preparation of land surface analysis for the period Jan-2011 - Dec-2013 using offline 2D-Noah land surface model (LSM) based land data assimilation system (LDAS) over Indian region (5 - 39N, 60 - 100E) hereafter referred as LDASI. The surface temperature, specific humidity, horizontal winds and pressure as atmospheric forcing parameters are derived from Modern-Era Retrospective Analysis for Research and Applications (MERRA). The downward (solar and thermal) radiation and precipitation is obtained from European Centre for Medium Range Forecast (ECMWF) and Tropical Rainfall Measuring Mission (TRMM) respectively. The sensitivity experiments are conducted by introducing perturbation in one atmospheric forcing parameter at a time keeping the other parameters unchanged. Influence of temperature, specific humidity, downward (shortwave and long wave) radiation, rain-rate and wind speed is investigated by conducted 13 numerical experiments. It is observed that the land surface analysis from LDASI is most sensitive to the downward longwave radiation and least sensitive to wind speed. The analysis is also substantially influenced by the surface air temperature. The annual mean soil moisture at 5 cm is decreased by 12-15% if the downward long-wave radiation is increased by 20% and it is increased by 15% if the downward long-wave radiation is decreased by 20%. The influence is even more in the Himalayan region but the increase in long-wave radiation leads to increase in soil moisture and similar influence on decrease because downward long-wave radiation leads glacier melting. The annual mean soil temperature in the analysis is increased by 2.2 K if surface

  7. Atmospheric tracer experiments for regional dispersion studies

    SciTech Connect

    Heffter, J.L.; Ferber, G.J.

    1980-01-01

    Tracer experiments are being conducted to verify atmospheric transport and dispersion calculations at distances from tens to hundreds of km from pollutant sources. In one study, a 2 1/2 year sampling program has been carried out at 13 sites located 30 to 140 km from a source of /sup 85/Kr at the Savannah River Plant in South Carolina. Average weekly concentrations as well as twice-daily concentrations were obtained. Sampling data and meteorological data, including surface, tower, and rawinsonde observations are available on magnetic tape for model verification studies. Some verification results for the Air Resources Laboratories Atmospheric Transort and Dispersion Model (ARL-ATAD) are shown for averaging periods from one week to two years.

  8. Studies of influence of energy distribution on the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Sheng, Cheng

    The energy inputs into the upper atmosphere including both solar irradiation and geomagnetic energy can significantly change the upper atmosphere such as the neutral and plasma densities, velocities and temperatures. Therefore, the precise specification of the energy inputs is critical to estimate the ionosphere/thermosphere variation during both quiet and storm times. In order to improve the understanding of the energy distribution and its influence at high latitudes, specifically, we have conducted the following studies. (1) Estimation of the altitudinal distribution of Joule heating from COSMIC observations. Joule heating is the most significant way to dissipate geomagnetic energy at high latitudes. But the altitudinal distribution of Joule heating has not been studied in detail. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations from 2008 to 2011, the height-integrated Pedersen conductivities in both E (100-150 km) and F (150-600 km) regions and their ratio lambdaP (sumPE/sumPF) have been calculated. The result from data analysis (˜5.5) shows a smaller value than that from model (˜9), which indicates that the energy inputs into the F region may be underestimated in the model. Dependences of the ratio and the conductance in both E and F regions on the solar and geomagnetic activities have been studied as well. (2) The influence of cusp energy on the thermospheric winds has also been studied, through simulating a real event. The Global Ionosphere Thermosphere Model (GITM) has been run in different cases and under different resolutions to investigate the neutral dynamics around the cusp region. The results indicate that the heating added in the cusp causes the change of pressure gradient around the cusp and changes the neutral wind dynamics there. (3) Correlation of Poynting flux and soft particle precipitation in the dayside polar cap boundary regions has been investigated using DMSP satellite measurements

  9. Data on atmospheric transmission in the IR spectral region

    NASA Technical Reports Server (NTRS)

    Paramonova, N. N.; Kazakova, K. V.; Brounshteyn, A. M.

    1979-01-01

    The weakening of radiation by the atmosphere in the infrared region of the spectrum was studied. The instrument used for the measurements was the IKAU-1 infrared atmospheric unit, and measurements were carried out both on an inclined path and a near-earth horizontal path.

  10. Atmospheric characteristics statistic study of Ruse region, Bulgaria

    NASA Astrophysics Data System (ADS)

    Zheleva, I.; Filipova, M.

    2016-10-01

    Temperature, air humidity and atmospheric pressure measurements in Ruse region for 40 years period are statistically studied in this paper. Descriptive statistics, Pearson correlation coefficients and linear regression models for these characteristics are presented and commented. The most variable atmospheric parameter is air humidity during the spring seasons. The hardest change of temperature and atmospheric pressure is during January. Temperature has biggest change in January and smallest - in July. Humidity has biggest change in April and smallest - in October. Atmospheric pressure has biggest change in January and smallest - in July. Characteristics temperature and atmospheric pressure of spring (April) and autumn (October) are very similar. Summer temperatures and atmospheric pressure (July) have smallest change. The atmospheric temperature data for Ruse region are also compared with the official basic data for Bulgaria. It is shown that mean values of the temperature in Ruse region are bigger than the mean temperature for Bulgaria. It is shown that the winter and spring temperatures for Ruse region are slightly going up lately which could be connected with the typical for Ruse region air pollution especially by particle matter.

  11. Region effects influence local tree species diversity

    PubMed Central

    Ricklefs, Robert E.; He, Fangliang

    2016-01-01

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species. PMID:26733680

  12. Region effects influence local tree species diversity.

    PubMed

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species. PMID:26733680

  13. Region effects influence local tree species diversity.

    PubMed

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  14. Topographic Influence and Atmospheric Dynamics in the Indian Wells Valley

    NASA Astrophysics Data System (ADS)

    Uher, Erich J.

    Indian Wells Valley (IWV) is home to the China Lake Naval Air Weapons Station (NAWS) whose operations necessitate regional forecasting and weather analysis relevant to aviation and plume release scenarios. In order to better understand the terrain influenced mesoscale circulations in the varied complex terrain of Indian Wells Valley surrounding Ridgecrest, four seasonal WRF simulations were analyzed using linear shallow water theory and nonlinear theory for flows over two-dimensional mountains. The goal is to better understand the relationships between atmospheric dynamical processes and the wind/thermal structure of the mesoscale at Indian Wells Valley. This will involve exploring relationships linking theoretical meteorology in complex terrain and advanced high resolution atmospheric modeling in this region. The WRF simulation results show several distinct circulations which rely on the interaction between complex terrain and the background weather conditions: 1) In calm synoptic conditions, diurnal processes guide the evolution of boundary layer stability and slope flows. 2) In periods of greatest seasonal surface heating (i.e. summer), the pressure gradient across the Sierra Nevada drives near surface westerlies across IWV. 3) In conditions with strong synoptic scale increase in stability and meridional winds across the Sierra Nevada, a downslope windstorm can develop in IWV. The downslope winds and compensatory gravity wave activity over IWV will conclude once there is a significant change in conditions aloft, or an increase in convective instability at the surface of IWV which prevents air aloft from sinking towards the surface. These results provide a better understanding of the mesoscale meteorology in this region and improve forecast and analysis for plume transport and aviation needs while also laying the groundwork for future projects managing environmental concerns in this region.

  15. Estimation of Regional Carbon Balance from Atmospheric Observations

    NASA Astrophysics Data System (ADS)

    Denning, S.; Uliasz, M.; Skidmore, J.

    2002-12-01

    Variations in the concentration of CO2 and other trace gases in time and space contain information about sources and sinks at regional scales. Several methods have been developed to quantitatively extract this information from atmospheric measurements. Mass-balance techniques depend on the ability to repeatedly sample the same mass of air, which involves careful attention to airmass trajectories. Inverse and adjoint techniques rely on decomposition of the source field into quasi-independent "basis functions" that are propagated through transport models and then used to synthesize optimal linear combinations that best match observations. A recently proposed method for regional flux estimation from continuous measurements at tall towers relies on time-mean vertical gradients, and requires careful trajectory analysis to map the estimates onto regional ecosystems. Each of these techniques is likely to be applied to measurements made during the North American Carbon Program. We have also explored the use of Bayesian synthesis inversion at regional scales, using a Lagrangian particle dispersion model driven by mesoscale transport fields. Influence functions were calculated for each hypothetical observation in a realistic diurnally-varying flow. These influence functions were then treated as basis functions for the purpose of separate inversions for daytime photosynthesis and 24-hour mean ecosystem respiration. Our results highlight the importance of estimating CO2 fluxes through the lateral boundaries of the model. Respiration fluxes were well constrained by one or two hypothetical towers, regardless of inflow fluxes. Time-varying assimilation fluxes were less well constrained, and much more dependent on knowledge of inflow fluxes. The small net difference between respiration and photosynthesis was the most difficult to determine, being extremely sensitive to knowledge of inflow fluxes. Finally, we explored the feasibility of directly incorporating mid-day concentration

  16. Regional climatic effects of atmospheric SO2 on Mars

    NASA Technical Reports Server (NTRS)

    Postawko, S. E.; Fanale, F. P.

    1992-01-01

    The conditions under which the valley networks on Mars may have formed remains controversial. The magnitude of an atmospheric greenhouse effect by an early massive CO2 atmosphere has recently been questioned by Kasting. Recent calculations indicate that if solar luminosity were less than about 86 percent of its current value, formation of CO2 clouds in the Martian atmosphere would depress the atmospheric lapse rate and reduce the magnitude of surface warming. In light of recent revisions of magma generation on Mars during each Martian epoch, and the suggestions by Wanke et al. that the role of liquid SO2 should be more carefully explored, we have recalculated the potential greenhouse warming by atmospheric SO2 on Mars, with an emphasis on more localized effects. In the vicinity of an active eruption, the concentration of atmospheric SO2 will be higher than if it is assumed that the erupted SO2 is instantaneously globally distributed. The local steady-state concentration of SO2 is a function of the rate at which it is released, its atmospheric lifetime, and the rate at which local winds act to disperse the SO2. We have made estimates of eruption rates, length of eruption, and dispersion rates of volcanically released SO2, for a variety of atmospheric conditions and atmospheric lifetimes of SO2 to explore the maximum regional climatic effect of SO2.

  17. Regional atmospheric composition modeling with CHIMERE

    NASA Astrophysics Data System (ADS)

    Menut, L.; Bessagnet, B.; Khvorostyanov, D.; Beekmann, M.; Colette, A.; Coll, I.; Curci, G.; Foret, G.; Hodzic, A.; Mailler, S.; Meleux, F.; Monge, J.-L.; Pison, I.; Turquety, S.; Valari, M.; Vautard, R.; Vivanco, M. G.

    2013-01-01

    Tropospheric trace gas and aerosol pollutants have adverse effects on health, environment and climate. In order to quantify and mitigate such effects, a wide range of processes leading to the formation and transport of pollutants must be considered, understood and represented in numerical models. Regional scale pollution episodes result from the combination of several factors: high emissions (from anthropogenic or natural sources), stagnant meteorological conditions, velocity and efficiency of the chemistry and the deposition. All these processes are highly variable in time and space, and their relative importance to the pollutants budgets can be quantified within a chemistry-transport models (CTM). The offline CTM CHIMERE model uses meteorological model fields and emissions fluxes and calculates deterministically their behavior in the troposphere. The calculated three-dimensional fields of chemical concentrations can be compared to measurements to analyze past periods or used to make air quality forecasts and CHIMERE has enabled a fine understanding of pollutants transport during numerous measurements campaigns. It is a part of the PREVAIR french national forecast platform, delivering pollutant concentrations up to three days in advance. The model also allows scenario studies and long term simulations for pollution trends. The modelling of photochemical air pollution has reached a good level of maturity, and the latest projects involving CHIMERE now aim at increasing our understanding of pollution impact on health at the urban scale or at the other end of the spectrum for long term air quality and climate change interlinkage studies, quantifying the emissions and transport of pollen, but also, at a larger scale, analyzing the transport of pollutants plumes emitted by volcanic eruptions and forest fires.

  18. Influence of solar activity on Jupiter's atmosphere

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.

    2016-05-01

    The influx of solar energy to different latitudes while Jupiter's orbital motion around the Sun varies significantly. This leads to a change in the optical and physical characteristics of its atmosphere. Analysis of the data for 1850-1991 on determination of the integral magnitude Mj Jupiter in the V filter, and a comparison with the changes of the Wolf numbers W, characterizing the variations of solar activity (SA) - showed that the change of Mj in maxima of the SA - has minima for odd, and maximums - for the even of SA cycles. That is, changing of the Jupiter brightness in visible light is much evident 22.3-year magnetic cycle, and not just about the 11.1-year cycle of solar activity. Analysis of the obtained in 1960-2015 data on the relative distribution of brightness along the central meridian of Jupiter, for which we calculated the ratio of the brightness Aj of northern to the southern part of the tropical and temperate latitudinal zones, allowed to approximate the change of Aj by sinusoid with a period of 11.91±0.07 earth years. Comparison of time variation of Aj from changes in the index of SA R, and the movement of the planet in its orbit - indicates the delay of response of the visible cloud layer in the atmosphere of the Sun's exposure mode for 6 years. This value coincides with the radiative relaxation of the hydrogen-helium atmosphere

  19. Atmospheric influence on volcano-acoustic signals

    NASA Astrophysics Data System (ADS)

    Matoza, Robin; de Groot-Hedlin, Catherine; Hedlin, Michael; Fee, David; Garcés, Milton; Le Pichon, Alexis

    2010-05-01

    Volcanoes are natural sources of infrasound, useful for studying infrasonic propagation in the atmosphere. Large, explosive volcanic eruptions typically produce signals that can be recorded at ranges of hundreds of kilometers propagating in atmospheric waveguides. In addition, sustained volcanic eruptions can produce smaller-amplitude repetitive signals recordable at >10 km range. These include repetitive impulsive signals and continuous tremor signals. The source functions of these signals can remain relatively invariant over timescales of weeks to months. Observed signal fluctuations from such persistent sources at an infrasound recording station may therefore be attributed to dynamic atmospheric propagation effects. We present examples of repetitive and sustained volcano infrasound sources at Mount St. Helens, Washington and Kilauea Volcano, Hawaii, USA. The data recorded at >10 km range show evidence of propagation effects induced by tropospheric variability at the mesoscale and microscale. Ray tracing and finite-difference simulations of the infrasound propagation produce qualitatively consistent results. However, the finite-difference simulations indicate that low-frequency effects such as diffraction, and scattering from topography may be important factors for infrasonic propagation at this scale.

  20. Atmospheric and Climate Aspects of Russian Regions Sustainability

    NASA Astrophysics Data System (ADS)

    Golitsyn, G. S.; Dubovsky, S. V.; Ginzburg, A. S.; Mokhov, I. I.; Khomyakov, P. M.

    Russia is one of the first countries created the national program of sustainable devel- opment. The Presidential Decree SOn the national strategy of the Russian Federation & cedil;in the environment protection and sustainable developmentT was issued by in 1994. Atmospheric and climate aspects play very important roles in the sustainable devel- opment at the regional level in Russia as well as at national one. Last year Russian Academy of Sciences in collaboration with some leaders of the local Russian au- thorities started the Project SSustainable development of Russia and its regionsT. In & cedil; this project the problems of Russian socio-economical development are considered together with regional atmospheric and climate changes, environmental and natural resources, population, urbanization, energetic and new technology development, and so on. The main problems of Russian regions socio-economical development related to global and local climate changes, environmental and natural resources, urbanization will be discussed.

  1. Pesticides in the atmosphere across Canadian agricultural regions.

    PubMed

    Yao, Yuan; Harner, Tom; Blanchard, Pierrette; Tuduri, Ludovic; Waite, Don; Poissant, Laurier; Murphy, Clair; Belzer, Wayne; Aulagnier, Fabien; Sverko, Ed

    2008-08-15

    The Canadian Atmospheric Network for Currently Used Pesticides (CANCUP) was the first comprehensive, nationwide air surveillance study of pesticides in Canada. This paper presentsthe atmospheric occurrence and distribution of pesticides including organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), acid herbicides (AHs), and neutral herbicides (NHs) during the spring to summer of 2004 and 2005 across agricultural regions in Canada. Atmospheric concentrations of pesticides varied within years and time periods, and regional characteristics were observed including the following: (i) highest air concentrations of several herbicides (e.g., mecoprop, triallate, and ethalfluralin) were found at Bratt's Lake, SK, a site in the Canadian Prairies; (ii) the west-coast site at Abbotsford, BC, had the maximum concentrations of diazinon; (iii) the fruit and vegetable growing region in Vineland, ON, showed highest levels for several insecticides including chlorpyrifos, endosulfan, and azinphos-methyl; (iv) high concentrations of atrazine and metolachlor were measured at St. Anicet, QC, a corn-growing region; (v) the Kensington site in PEI, Canada's largest potato-producing province, exhibited highest level of dimethoate. Analysis of particle- and gas-phase fractions of air samples revealed that most pesticides including OCPs, OPPs, and NHs exist mainly in the gas phase, while AHs exhibit more diversity in particle-gas partitioning behavior. This study also demonstrated that stirred up soil dust does not account for pesticides that are detected in the particle phase. The estimated dry and wet deposition fluxes indicate considerable atmospheric inputs for some current-use pesticides (CUPs). This data set represents the first measurements for many pesticides in the atmosphere, precipitation, and soil for given agricultural regions across Canada.

  2. Identifying human influences on atmospheric temperature.

    PubMed

    Santer, Benjamin D; Painter, Jeffrey F; Mears, Carl A; Doutriaux, Charles; Caldwell, Peter; Arblaster, Julie M; Cameron-Smith, Philip J; Gillett, Nathan P; Gleckler, Peter J; Lanzante, John; Perlwitz, Judith; Solomon, Susan; Stott, Peter A; Taylor, Karl E; Terray, Laurent; Thorne, Peter W; Wehner, Michael F; Wentz, Frank J; Wigley, Tom M L; Wilcox, Laura J; Zou, Cheng-Zhi

    2013-01-01

    We perform a multimodel detection and attribution study with climate model simulation output and satellite-based measurements of tropospheric and stratospheric temperature change. We use simulation output from 20 climate models participating in phase 5 of the Coupled Model Intercomparison Project. This multimodel archive provides estimates of the signal pattern in response to combined anthropogenic and natural external forcing (the fingerprint) and the noise of internally generated variability. Using these estimates, we calculate signal-to-noise (S/N) ratios to quantify the strength of the fingerprint in the observations relative to fingerprint strength in natural climate noise. For changes in lower stratospheric temperature between 1979 and 2011, S/N ratios vary from 26 to 36, depending on the choice of observational dataset. In the lower troposphere, the fingerprint strength in observations is smaller, but S/N ratios are still significant at the 1% level or better, and range from three to eight. We find no evidence that these ratios are spuriously inflated by model variability errors. After removing all global mean signals, model fingerprints remain identifiable in 70% of the tests involving tropospheric temperature changes. Despite such agreement in the large-scale features of model and observed geographical patterns of atmospheric temperature change, most models do not replicate the size of the observed changes. On average, the models analyzed underestimate the observed cooling of the lower stratosphere and overestimate the warming of the troposphere. Although the precise causes of such differences are unclear, model biases in lower stratospheric temperature trends are likely to be reduced by more realistic treatment of stratospheric ozone depletion and volcanic aerosol forcing.

  3. Identifying human influences on atmospheric temperature

    PubMed Central

    Santer, Benjamin D.; Painter, Jeffrey F.; Mears, Carl A.; Doutriaux, Charles; Caldwell, Peter; Arblaster, Julie M.; Cameron-Smith, Philip J.; Gillett, Nathan P.; Gleckler, Peter J.; Lanzante, John; Perlwitz, Judith; Solomon, Susan; Stott, Peter A.; Taylor, Karl E.; Terray, Laurent; Thorne, Peter W.; Wehner, Michael F.; Wentz, Frank J.; Wigley, Tom M. L.; Wilcox, Laura J.; Zou, Cheng-Zhi

    2013-01-01

    We perform a multimodel detection and attribution study with climate model simulation output and satellite-based measurements of tropospheric and stratospheric temperature change. We use simulation output from 20 climate models participating in phase 5 of the Coupled Model Intercomparison Project. This multimodel archive provides estimates of the signal pattern in response to combined anthropogenic and natural external forcing (the fingerprint) and the noise of internally generated variability. Using these estimates, we calculate signal-to-noise (S/N) ratios to quantify the strength of the fingerprint in the observations relative to fingerprint strength in natural climate noise. For changes in lower stratospheric temperature between 1979 and 2011, S/N ratios vary from 26 to 36, depending on the choice of observational dataset. In the lower troposphere, the fingerprint strength in observations is smaller, but S/N ratios are still significant at the 1% level or better, and range from three to eight. We find no evidence that these ratios are spuriously inflated by model variability errors. After removing all global mean signals, model fingerprints remain identifiable in 70% of the tests involving tropospheric temperature changes. Despite such agreement in the large-scale features of model and observed geographical patterns of atmospheric temperature change, most models do not replicate the size of the observed changes. On average, the models analyzed underestimate the observed cooling of the lower stratosphere and overestimate the warming of the troposphere. Although the precise causes of such differences are unclear, model biases in lower stratospheric temperature trends are likely to be reduced by more realistic treatment of stratospheric ozone depletion and volcanic aerosol forcing. PMID:23197824

  4. Chemical cycling and deposition of atmospheric mercury in polar regions: review of recent measurements and comparison with models

    NASA Astrophysics Data System (ADS)

    Angot, Hélène; Dastoor, Ashu; De Simone, Francesco; Gårdfeldt, Katarina; Gencarelli, Christian N.; Hedgecock, Ian M.; Langer, Sarka; Magand, Olivier; Mastromonaco, Michelle N.; Nordstrøm, Claus; Pfaffhuber, Katrine A.; Pirrone, Nicola; Ryjkov, Andrei; Selin, Noelle E.; Skov, Henrik; Song, Shaojie; Sprovieri, Francesca; Steffen, Alexandra; Toyota, Kenjiro; Travnikov, Oleg; Yang, Xin; Dommergue, Aurélien

    2016-08-01

    Mercury (Hg) is a worldwide contaminant that can cause adverse health effects to wildlife and humans. While atmospheric modeling traces the link from emissions to deposition of Hg onto environmental surfaces, large uncertainties arise from our incomplete understanding of atmospheric processes (oxidation pathways, deposition, and re-emission). Atmospheric Hg reactivity is exacerbated in high latitudes and there is still much to be learned from polar regions in terms of atmospheric processes. This paper provides a synthesis of the atmospheric Hg monitoring data available in recent years (2011-2015) in the Arctic and in Antarctica along with a comparison of these observations with numerical simulations using four cutting-edge global models. The cycle of atmospheric Hg in the Arctic and in Antarctica presents both similarities and differences. Coastal sites in the two regions are both influenced by springtime atmospheric Hg depletion events and by summertime snowpack re-emission and oceanic evasion of Hg. The cycle of atmospheric Hg differs between the two regions primarily because of their different geography. While Arctic sites are significantly influenced by northern hemispheric Hg emissions especially in winter, coastal Antarctic sites are significantly influenced by the reactivity observed on the East Antarctic ice sheet due to katabatic winds. Based on the comparison of multi-model simulations with observations, this paper discusses whether the processes that affect atmospheric Hg seasonality and interannual variability are appropriately represented in the models and identifies research gaps in our understanding of the atmospheric Hg cycling in high latitudes.

  5. The Outsized Influence of a Primordial Lunar Atmosphere

    NASA Astrophysics Data System (ADS)

    Saxena, Prabal; Elkins-Tanton, Linda T.; Petro, Noah; Mandell, Avi

    2016-10-01

    Immediately following formation of the moon, its surface was subject to radiative influences from the Lunar Magma Ocean, an early Earth that radiated like a mid type M Dwarf Star, and the early Sun. These contributions have been hypothesized to have produced a vapor pressure atmosphere on the Moon. We model the early atmosphere of the Moon using an atmospheric model originally developed for Io. We also use a magma ocean crystallization model that finds that heating from the early Earth delays crystallization of the Lunar Magma Ocean and contributes to a moderate pressure and collapsing metal-dominated atmosphere on the earthside of the Moon until lid formation. The atmosphere is characterized by maximum pressures ~1 bar and strong horizontal supersonic winds that decreased as the Moon's orbital separation increased. Crustal and other compositional asymmetries may have been influenced by this atmosphere. The atmosphere transported significant amounts of mass horizontally and may have been a source for present day depletions and heterogeneities of moderately volatile elements on the lunar surface.

  6. Improving SLCF Science in the Himalayan Region: ICIMOD's Atmosphere Initiative

    NASA Astrophysics Data System (ADS)

    Panday, A. K.; Pradhan, B. B.; Surapipith, V.

    2013-12-01

    What fraction of the black carbon arriving on Yala Glacier in Langtang, Nepal, is from cooking fires in the houses in the valley below? What fraction is from elsewhere in rural Nepal? What fraction is from industrial and transport sources in Kathmandu? What fraction is from northern India and beyond? What fraction is from the high altitude forest fires that take place during March or April? Effectively mitigating the impacts of black carbon and other short-lived climate forcers requires detailed understanding not just of emissions and impacts, but also of the atmospheric transport pathways that connect the two. In mountainous areas of the Hindu-Kush Himalaya detailed quantitative knowledge about emissions, atmospheric processes, and impacts is still largely missing. The International Centre for Integrated Mountain Development (ICIMOD) is an intergovernmental organization covering Afghanistan, Pakistan, India, Nepal, China, Bhutan, Bangladesh, and Myanmar. ICIMOD's recently established Atmosphere Initiative not only assesses mitigation options and contributes to policy and capacity building in the region, but also works actively to promote collaboration among researchers in the region, while building up an in-house team whose research will address key questions about SLCF. In Spring 2013 ICIMOD's Atmosphere Initiative, in collaboration with the Institute for Advanced Sustainability Studies (IASS) in Potsdam, Germany, carried out the largest field campaign to date in Nepal, hosting instruments belonging to dozens of institutions around the world, at nine field site within and upwind of the Kathmandu Valley, Nepal. The dataset that has been collected gives unprecedented insights into the emissions and atmospheric processes taking place downwind of and within the largest urban agglomeration in the Himalaya region. Meanwhile, in collaboration with national partner institutions, ICIMOD is in the process of setting up one atmospheric observatory each in Bhutan and in

  7. Arctic Storms in a Regionally Refined Atmospheric General Circulation Model

    NASA Astrophysics Data System (ADS)

    Roesler, E. L.; Taylor, M.; Boslough, M.; Sullivan, S.

    2014-12-01

    Regional refinement in an atmospheric general circulation model is a new tool in atmospheric modeling. A regional high-resolution solution can be obtained without the computational cost of running a global high-resolution simulation as global climate models have increasing ability to resolve smaller spatial scales. Previous work has shown high-resolution simulations, i.e. 1/8 degree, and variable resolution utilities have resolved more fine-scale structure and mesoscale storms in the atmosphere than their low-resolution counterparts. We will describe an experiment designed to identify and study Arctic storms at two model resolutions. We used the Community Atmosphere Model, version 5, with the Spectral Element dynamical core at 1/8-degree and 1 degree horizontal resolutions to simulate the climatological year of 1850. Storms were detected using a low-pressure minima and vorticity maxima - finding algorithm. It was found the high-resolution 1/8-degree simulation had more storms in the Northern Hemisphere than the low-resolution 1-degree simulation. A variable resolution simulation with a global low resolution of 1-degree and a high-resolution refined region of 1/8 degree over a region in the Arctic is planned. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. 2014-16460A

  8. Middle Atmosphere Temperature and Dynamics as Revealed from D-region Observations

    NASA Technical Reports Server (NTRS)

    Danilov, A. D.

    1984-01-01

    The concept of so-called meteorological control of the ionospheric D-region is presently undergoing development. According to this concept the electron concentration in this region is governed not only by solar and geomagnetic parameters but strongly depends on the temperature and dynamical regime of the mesosphere and stratosphere. How this connection between D-region and meteorological parameters can be used to obtain some information about middle atmosphere temperature and dynamics is examined. The essential points of the meteorological control concept are reviewed and the influence of turbulence on nitric oxide distribution and thus the ion production rate is discussed.

  9. Influence of the African Great Lakes on the regional climate

    NASA Astrophysics Data System (ADS)

    Thiery, Wim; Davin, Edouard; Panitz, Hans-Jürgen; Demuzere, Matthias; Lhermitte, Stef; van Lipzig, Nicole

    2015-04-01

    Although the African Great Lakes are important regulators for the East-African climate, their influence on atmospheric dynamics and the regional hydrological cycle remains poorly understood. We aim to assess this impact by conducting a regional climate model simulation which resolves individual lakes and explicitly computes lake temperatures. The regional climate model COSMO-CLM, coupled to a state-of-the-art lake parameterization scheme and land surface model, is used to dynamically downscale the COSMO-CLM CORDEX-Africa evaluation simulation to 7 km grid spacing for the period 1999-2008. Evaluation of the model reveals good performance compared to both in-situ and satellite observations, especially for spatio-temporal variability of lake surface temperatures and precipitation. Model integrations indicate that the four major African Great Lakes almost double precipitation amounts over their surface relative to a simulation without lakes, but hardly exert any influence on precipitation beyond their shores. The largest lakes also cool their near-surface air, this time with pronounced downwind influence. The lake-induced cooling happens during daytime, when the lakes absorb incoming solar radiation and inhibit upward turbulent heat transport. At night, when this heat is released, the lakes warm the near-surface air. Furthermore, Lake Victoria has profound influence on atmospheric dynamics and stability as it induces cellular motion with over-lake convective inhibition during daytime, and the reversed pattern at night. Overall, this study shows the added value of resolving individual lakes and realistically representing lake surface temperatures for climate studies in this region. Thiery, W., Davin, E., Panitz, H.-J., Demuzere, M., Lhermitte, S., van Lipzig, N.P.M., The impact of the African Great Lakes on the regional climate, J. Climate (in review).

  10. Fire Influences on Atmospheric Composition, Air Quality, and Climate

    NASA Technical Reports Server (NTRS)

    Voulgarakis, Apostolos; Field, Robert D.

    2015-01-01

    Fires impact atmospheric composition through their emissions, which range from long-lived gases to short-lived gases and aerosols. Effects are typically larger in the tropics and boreal regions but can also be substantial in highly populated areas in the northern mid-latitudes. In all regions, fire can impact air quality and health. Similarly, its effect on large-scale atmospheric processes, including regional and global atmospheric chemistry and climate forcing, can be substantial, but this remains largely unexplored. The impacts are primarily realised in the boundary layer and lower free troposphere but can also be noticeable in upper troposphere/lower stratosphere (UT/LS) region, for the most intense fires. In this review, we summarise the recent literature on findings related to fire impact on atmospheric composition, air quality and climate. We explore both observational and modelling approaches and present information on key regions and on the globe as a whole. We also discuss the current and future directions in this area of research, focusing on the major advances in emission estimates, the emerging efforts to include fire as a component in Earth system modelling and the use of modelling to assess health impacts of fire emissions.

  11. The Middle Atmospheric variability over Indian region during Tropical cyclone

    NASA Astrophysics Data System (ADS)

    Bhagavathiammal, G. J.

    In order to study the various characteristics of atmosphere during the passage of tropical cyclones, some atmospheric parameters over Indian region has been studied. The tropospheric variability has been studied with the help of surface pressure variation obtained from microbarograph at Tirunelveli (8.7oN, 77.8oE). The stratospheric ozone variability has been obtained from the TOMS (Total Ozone Mapping Spectrometer) satellite over the Bay of Bengal as well as Arabian Ocean. The ionospheric current over Indian region has been obtained from the network of Indian Institute of Geomagnetism. We have studied the ionospheric current variations over Tirunelveli (inside the electrojet region) and Alibag (outside the electrojet region). The tropospheric cyclone track has been obtained from the Indian Meteorological Department. The pressure variation obtained over Tirunelveli has been converted into FFT spectrum and it shows the enhancement in power of surface gravity waves of period about 150 min. The magnitude of enhancement depends upon the distance of the cyclone track. The stratospheric ozone obtained by TOMS shows an increase in ozone during tropical depression by about 10 DU followed by decrease in total ozone up to 25 DU along the cyclone track. The ionospheric current shows the changes in power of Inertial Gravity Waves (IGW) over Tirunelveli as well as Alibag. The power of IGW over Tirunelveli shows decrease by about 25

  12. Critical review of studies on atmospheric dispersion in coastal regions

    SciTech Connect

    Shearer, D.L.; Kaleel, R.J.

    1982-09-01

    This study effort was required as a preliminary step prior to initiation of field measurements of atmospheric dispersion in coastal regions. The Nuclear Regulatory Commission (NRC) is in the process of planning an extensive field measurement program to generate data which will serve as improved data bases for licensing decisions, confirmation of regulations, standards, and guides, and for site characterizations. The study being reported here is an effort directed to obtaining as much information as is possible from existing studies that is relevant toward NRC's objectives. For this study, reports covering research and meteorological measurements conducted for industrial purposes, utility needs, military objectives, and academic studies were obtained and critically reviewed in light of NRC's current data needs. This report provides an interpretation of the extent of existing usable information, an indication of the potential for tailoring existing research toward current NRC information needs, and recommendations for several follow-on studies which could provide valuable additional information through reanalysis of the data. Recommendations are also offered regarding new measurement programs. Emphasis is placed on the identification and acquisition of data from atmospheric tracer studies conducted in coastal regions. A total of 225 references were identified which deal with the coastal atmosphere, including meteorological and tracer measurement programs, theoretical descriptions of the relevant processes, and dispersion models.

  13. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  14. Influence of dust loading on atmospheric ionizing radiation on Mars

    NASA Astrophysics Data System (ADS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  15. A new mechanism for regional atmospheric chemistry modeling

    NASA Astrophysics Data System (ADS)

    Stockwell, William R.; Kirchner, Frank; Kuhn, Michael; Seefeld, Stephan

    1997-11-01

    A new gas-phase chemical mechanism for the modeling of regional atmospheric chemistry, the "Regional Atmospheric Chemistry Mechanism" (RACM) is presented. The mechanism is intended to be valid for remote to polluted conditions and from the Earth's surface through the upper troposphere. The RACM mechanism is based upon the earlier Regional Acid Deposition Model, version 2 (RADM2) mechanism [Stockwell et al., 1990] and the more detailed Euro-RADM mechanism [Stockwell and Kley, 1994]. The RACM mechanism includes rate constants and product yields from the most recent laboratory measurements, and it has been tested against environmental chamber data. A new condensed reaction mechanism is included for biogenic compounds: isoprene, α-pinene, and d-limonene. The branching ratios for alkane decay were reevaluated, and in the revised mechanism the aldehyde to ketone ratios were significantly reduced. The relatively large amounts of nitrates resulting from the reactions of unbranched alkenes with NO3 are now included, and the production of HO from the ozonolysis of alkenes has a much greater yield. The aromatic chemistry has been revised through the use of new laboratory data. The yield of cresol production from aromatics was reduced, while the reactions of HO, NO3, and O3 with unsaturated dicarbonyl species and unsaturated peroxynitrate are now included in the RACM mechanism. The peroxyacetyl nitrate chemistry and the organic peroxy radical-peroxy radical reactions were revised, and organic peroxy radical +NO3 reactions were added.

  16. The Regional Environmental Impacts of Atmospheric Aerosols over Egypt

    NASA Astrophysics Data System (ADS)

    Zakey, Ashraf; Ibrahim, Alaa

    2015-04-01

    Identifying the origin (natural versus anthropogenic) and the dynamics of aerosols over Egypt at varying temporal and spatial scales provide valuable knowledge on the regional climate impacts of aerosols and their ultimate connections to the Earth's regional climate system at the MENA region. At regional scale, Egypt is exposed to air pollution with levels exceeding typical air-quality standards. This is particularly true for the Nile Delta region, being at the crossroads of different aerosol species originating from local urban-industrial and biomass-burning activities, regional dust sources, and European pollution from the north. The Environmental Climate Model (EnvClimA) is used to investigate both of the biogenic and anthropogenic aerosols over Egypt. The dominant natural aerosols over Egypt are due to the sand and dust storms, which frequently occur during the transitional seasons (spring and autumn). In winter, the maximum frequency reaches 2 to 3 per day in the north, which decreases gradually southward with a frequency of 0.5-1 per day. Monitoring one of the most basic aerosol parameters, the aerosol optical depth (AOD), is a main experimental and modeling task in aerosol studies. We used the aerosol optical depth to quantify the amount and variability of aerosol loading in the atmospheric column over a certain areas. The aerosols optical depth from the model is higher in spring season due to the impacts of dust activity over Egypt as results of the westerly wind, which carries more dust particles from the Libyan Desert. The model result shows that the mass load of fine aerosols has a longer life-time than the coarse aerosols. In autumn season, the modelled aerosol optical depth tends to increase due to the biomass burning in the delta of Egypt. Natural aerosol from the model tends to scatter the solar radiation while most of the anthropogenic aerosols tend to absorb the longwave solar radiation. The overall results indicate that the AOD is lowest in winter

  17. Polychlorinated biphenyls and organochlorine pesticides in atmospheric air of the Northern Hovsgol region in 2008-2013

    NASA Astrophysics Data System (ADS)

    Mamontova, E. A.; Tarasova, E. N.; Goreglyad, A. V.; Tkachenko, L. L.; Mamontov, A. A.; Kuzmin, M. I.

    2015-10-01

    Results of the study of organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB) from the listing of the Stockholm Convention in atmospheric air of the Northern Hovsgol region at the base of the "Khankh" stationary, Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, in 2008-2013 in the absence of clear sources of these compounds are considered. Quantitative and qualitative changes in the concentration of PCB and OCP in atmospheric air of the Northern Hovsgol region in 2008-2013 characterizing the influence of natural (annual temperature variations) and anthropogenic (atmospheric transportation from the territories of neighboring countries) are shown.

  18. Extensive regional atmospheric hydrocarbon pollution in the southwestern United States.

    PubMed

    Katzenstein, Aaron S; Doezema, Lambert A; Simpson, Isobel J; Blake, Donald R; Rowland, F Sherwood

    2003-10-14

    Light alkane hydrocarbons are present in major quantities in the near-surface atmosphere of Texas, Oklahoma, and Kansas during both autumn and spring seasons. In spring 2002, maximum mixing ratios of ethane [34 parts per 109 by volume (ppbv)], propane (20 ppbv), and n-butane (13 ppbv) were observed in north-central Texas. The elevated alkane mixing ratios are attributed to emissions from the oil and natural gas industry. Measured alkyl nitrate mixing ratios were comparable to urban smog values, indicating active photochemistry in the presence of nitrogen oxides, and therefore with abundant formation of tropospheric ozone. We estimate that 4-6 teragrams of methane are released annually within the region and represents a significant fraction of the estimated total U.S. emissions. This result suggests that total U.S. natural gas emissions may have been underestimated. Annual ethane emissions from the study region are estimated to be 0.3-0.5 teragrams.

  19. Analysis of the cathodic region of atmospheric pressure discharges

    NASA Astrophysics Data System (ADS)

    Schmitz, H.; Riemann, K.-U.

    2002-07-01

    The cathodic region of atmospheric pressure arcs is dominated by a number of different mechanisms. This makes a theoretical model extremely difficult. A description of this region based on fundamental physical principles is given. Using a previously published model of the inhomogeneous boundary layer of a Saha plasma (Schmitz H and Riemann K-U 2001 J. Phys. D: Appl. Phys. 34 1193), the description is set on a firm theoretical basis. A number of equations including the energy balances of plasma boundary and cathode body lead to a maximum closure of the system. The values for the boundary conditions toward the plasma column could be motivated by a simple minimum principle argument thus eliminating all arbitrary fitting parameters. Results are given for a variety of external parameters and three different discharge gases. The comparison with experimental results shows excellent agreement.

  20. Investigation of the influence of atmospheric stability and turbulence on land-atmosphere exchange

    NASA Astrophysics Data System (ADS)

    Osibanjo, O.; Holmes, H.

    2015-12-01

    Surface energy fluxes are exchanged between the surface of the earth and the atmosphere and impact weather, climate, and air quality. The radiation from the sun triggers the surface-atmosphere interaction during the day as heat is transmitted to the surface and the surface heats the air directly above generating wind (i.e., thermal turbulence) that transports heat, moisture, and momentum in the atmospheric boundary layer (ABL). This process is impacted by greenhouse gasses (i.e., water vapor, carbon dioxide and other trace gases) that absorb heat emitted by the earth's surface. The concentrations of atmospheric greenhouse gasses are increasing leading to changes in ABL dynamics as a result of the changing surface energy balance. The ABL processes are important to characterize because they are difficult to parameterize in global and regional scale atmospheric models. Empirical data can be collected using eddy covariance micrometeorological methods to measure turbulent fluxes (e.g., sensible heat, moisture, and CO2) and quantify the exchange between the surface and the atmosphere. The objective of this work is to calculate surface fluxes using observational data collected during one week in September 2014 from a monitoring site in Echo, Oregon. The site is located in the Columbia Basin with rolling terrain, irrigated farmland, and over 100 wind turbines. The 10m tower was placed in a small valley depression to isolate nighttime cold air pools. This work will present observations of momentum, sensible heat, moisture, and carbon dioxide fluxes from data collected at a sampling frequency of 10Hz at four heights. Atmospheric stability is determined using Monin-Obukov length and flux Richardson number, and the impact of stability on surface-atmosphere exchange is investigated. This work will provide a better understanding of surface fluxes and mixing, particularly during stable ABL periods, and the results can be used to compare with numerical models.

  1. Synergies Between Grace and Regional Atmospheric Modeling Efforts

    NASA Astrophysics Data System (ADS)

    Kusche, J.; Springer, A.; Ohlwein, C.; Hartung, K.; Longuevergne, L.; Kollet, S. J.; Keune, J.; Dobslaw, H.; Forootan, E.; Eicker, A.

    2014-12-01

    In the meteorological community, efforts converge towards implementation of high-resolution (< 12km) data-assimilating regional climate modelling/monitoring systems based on numerical weather prediction (NWP) cores. This is driven by requirements of improving process understanding, better representation of land surface interactions, atmospheric convection, orographic effects, and better forecasting on shorter timescales. This is relevant for the GRACE community since (1) these models may provide improved atmospheric mass separation / de-aliasing and smaller topography-induced errors, compared to global (ECMWF-Op, ERA-Interim) data, (2) they inherit high temporal resolution from NWP models, (3) parallel efforts towards improving the land surface component and coupling groundwater models; this may provide realistic hydrological mass estimates with sub-diurnal resolution, (4) parallel efforts towards re-analyses, with the aim of providing consistent time series. (5) On the other hand, GRACE can help validating models and aids in the identification of processes needing improvement. A coupled atmosphere - land surface - groundwater modelling system is currently being implemented for the European CORDEX region at 12.5 km resolution, based on the TerrSysMP platform (COSMO-EU NWP, CLM land surface and ParFlow groundwater models). We report results from Springer et al. (J. Hydromet., accept.) on validating the water cycle in COSMO-EU using GRACE and precipitation, evapotranspiration and runoff data; confirming that the model does favorably at representing observations. We show that after GRACE-derived bias correction, basin-average hydrological conditions prior to 2002 can be reconstructed better than before. Next, comparing GRACE with CLM forced by EURO-CORDEX simulations allows identifying processes needing improvement in the model. Finally, we compare COSMO-EU atmospheric pressure, a proxy for mass corrections in satellite gravimetry, with ERA-Interim over Europe at

  2. Characteristics of atmospheric CO2 and CH4 at the Shangdianzi regional background station in China

    NASA Astrophysics Data System (ADS)

    Fang, Shuang-xi; Tans, Pieter P.; Dong, Fan; Zhou, Huaigang; Luan, Tian

    2016-04-01

    Atmospheric CO2 and CH4 have been continuously measured at the Shangdianzi regional background station (SDZ) in China from 2009 to 2013. Based on the influences of local surface wind and long-distance transport, the observed records were flagged into locally influenced, Beijing-Tianjin-Hebei (BTH) influenced, and Russia, Mongolia, and Inner Mongolia autonomous region influenced (RMI). ∼ 81.4% of CO2 and ∼75.6% of CH4 mole fractions were flagged as locally representative, indicating that the atmospheric CO2 and CH4 at SDZ were strongly influenced by local sources and sinks. Cluster analysis of back trajectories proved that the atmospheric CO2 and CH4 were influenced by air masses from northwest (RMI) or from south and southeast (BTH). The CO2 and CH4 mole fractions in BTH are always higher than in RMI, with the largest difference of 11.5 ± 0.3 ppm for CO2 and 102 ± 1 ppb for CH4 in July. The annual growth rates of CO2 and CH4 in BTH are 3.8 ± 0.01 ppm yr-1 and 10 ± 0.1 ppb yr-1, respectively, which are apparently higher than those of the RMI and the global means. The long-term trends of CO2 and CH4 in BTH are deviating from those in RMI, with ratios of ∼1.0 ppm yr-1 for CO2 and ∼2 ppb yr-1 for CH4, indicating the strengths of CO2 and CH4 emission in Beijing-Tianjin-Hebei plain increased more than 20% every year.

  3. Dynamical characteristics of atmospheric aerosols over IG region

    NASA Astrophysics Data System (ADS)

    Sharma, Manish; Singh, Ramesh P.; Kumar, Rajesh

    2016-05-01

    The dynamical characteristics of atmospheric aerosols over the Indo-Gangetic (IG) region are primarily dependent on the geographical settings and meteorological conditions. Detailed analysis of multi satellite data and ground observations have been carried out over three different cities i.e. Kanpur, Greater Noida and Amritsar during 2010-2013. Level-3 Moderate Resolution Imaging Spectroradiometer (MODIS) terra daily global grid product with spatial resolution of 1° × 1° shows the mean AOD at 500 nm wavelength value of 0.73, 0.70 and 0.67 with the standard deviation of 0.43, 0.39 and 0.36 respectively over Amritsar, Greater Noida and Kanpur. Our detailed analysis shows characteristic behavior of aerosols from west to east in the IG region depending upon the proximity of desert regions of Arabia. We have observed large influx of dusts from the Thar desert and Arabia peninsula during pre-monsoon season (April-June), highly affecting Amritsar which is close to the desert region.

  4. Relative Influence of Initial Surface and Atmospheric Conditions on Seasonal Water and Energy Balances

    NASA Technical Reports Server (NTRS)

    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.

  5. Middle Atmosphere Program. Handbook for MAP. Volume 16: Atmospheric Structure and Its Variation in the Region 20 to 120 Km. Draft of a New Reference Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Labitzke, K. (Editor); Barnett, J. J. (Editor); Edwards, B. (Editor)

    1985-01-01

    A draft of a new reference atmosphere for the region between 20 and 80 km which depends largely on recent satellite experiments covering the globe from 80 deg S to 80 deg N is given. A separate international tropical reference atmosphere is given, as well as reference ozone models for the middle atmosphere.

  6. Reactive nitrogen oxides in remote regions: Atmospheric concentrations and atmosphere/biosphere exchange

    SciTech Connect

    Bakwin, P.S.

    1989-01-01

    Atmospheric concentrations and elements of the atmospheres/biosphere exchange of reactive nitrogen oxides (NO{sub y}) were measured in two disparate, remote ecosystems: the Amazon rain forest in central Brazil (wet season, 1987) and the moist tundra of southwestern Alaska (summer, 1988). Concentrations of total NO{sub y} and the NO{sub y} species NO and NO{sub 2} in both locations were found to be generally low compared to the few other remote continental regions where measurements have been made. In Alaska the concentrations of NO + NO{sub 2} (=NO{sub x}) were in the range (10-20 pptv) thought to be more typical of marine air masses. Occasional observations of higher concentrations, especially in Brazil, indicated that polluted air reached even these remote sites. The soils in both locations were modest sources of NO{sub x} to the atmosphere. In Brazil this source was approximately balanced, during unpolluted periods, by dry deposition of other NO{sub y} species to the forest canopy, while in Alaska the net flux of NO{sub y} was strongly downward. Diurnal variations in the NO{sub y} concentrations and fluxes at both sites suggest that dry deposition rates are controlled by the supply of reactive components such as HNO{sub 3} and that a significant portion of the observed NO{sub y} may consist of compounds with relatively long tropospheric lifetimes which are resistant to dry deposition.

  7. Role of solar influences on geomagnetosphere and upper atmosphere

    NASA Astrophysics Data System (ADS)

    Kumar Tripathi, Arvind

    The Earth's magnetosphere and upper atmosphere can be greatly perturbed by variations in the solar luminosity caused by disturbances on the solar surface. The state of near-Earth space environment is governed by the Sun and is very dynamic on all spatial and temporal scale. The geomagnetic field which protects the Earth from solar wind and cosmic rays is also essential to the evolution of life; its variations can have either direct or indirect effect on human physiology and health state even if the magnitude of the disturbance is small. Geomagnetic disturbances are seen at the surface of the Earth as perturbations in the components of the geomagnetic field, caused by electric currents flowing in the magnetosphere and upper atmosphere. Ionospheric and thermospheric storms also result from the redistribution of particles and fields. Global thermospheric storm winds and composition changes are driven by energy injection at high latitudes. These storm effects may penetrate downwards to the lower thermosphere and may even perturb the mesosphere. Many of the ionospheric changes at mid-latitude can be understood as a response to thermospheric perturbations. The transient bursts of solar energetic particles, often associated with large solar transients, have been observed to have effects on the Earth's middle and lower atmosphere, including the large-scale destruction of polar stratospheric and tropospheric ozone. In the present, we have discussed effect of solar influences on earth's magnetosphere and upper atmosphere that are useful to space weather and global warming, on the basis of various latest studies.

  8. Atmospheric Impact of Large Methane Emission in the Arctic Region

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D.; Reagan, M. T.; Collins, W.; Elliott, S. M.; Maltrud, M. E.

    2011-12-01

    A highly potent greenhouse gas, methane, is locked in the solid phase as ice-like deposits containing a mixture of water and gas (mostly methane) called clathrates, in ocean sediments and underneath permafrost regions. Clathrates are stable under high pressure and low temperatures. Recent estimates suggest that about 1600 - 2000GtC of clathrates are present in oceans and 400GtC in Arctic permafrost (Archer et al.2009) which is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could alter the geothermal gradient, which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could be of particular importance in the shallow part of the Arctic Ocean where the clathrates are found in depths of only 300m. In this presentation, we shall show results from our ongoing simulation of a scenario of large scale methane outgassing from clathrate dissociation due to warming ocean temperatures in the Arctic based on ocean sediment modeling. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with fast atmospheric chemistry module to simulate the response to increasing methane emissions in the Barents Sea, Canadian Archipelago and the Sea of Okhotsk. The simulation shows the effect these methane emissions could have on global surface methane, surface ozone, surface air temperature and other related indices. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-491764

  9. Atmospheric energetics in regions of intense convective activity

    NASA Technical Reports Server (NTRS)

    Fuelberg, H. E.

    1977-01-01

    Synoptic-scale budgets of kinetic and total potential energy are computed using 3- and 6-h data at nine times from NASA's fourth Atmospheric Variability Experiment (AVE IV). Two intense squall lines occurred during the period. Energy budgets for areas that enclose regions of intense convection are shown to have systematic changes that relate to the life cycles of the convection. Some of the synoptic-scale energy processes associated with the convection are found to be larger than those observed in the vicinity of mature cyclones. Volumes enclosing intense convection are found to have large values of cross-contour conversion of potential to kinetic energy and large horizontal export of kinetic energy. Although small net vertical transport of kinetic energy is observed, values at individual layers indicate large upward transport. Transfer of kinetic energy from grid to subgrid scales of motion occurs in the volumes. Latent heat release is large in the middle and upper troposphere and is thought to be the cause of the observed cyclic changes in the budget terms. Total potential energy is found to be imported horizontally in the lower half of the atmosphere, transported aloft, and then exported horizontally. Although local changes of kinetic energy and total potential energy are small, interaction between volumes enclosing convection with surrounding larger volumes is quite large.

  10. Regional forecasting with global atmospheric models; Final report

    SciTech Connect

    Crowley, T.J.; Smith, N.R.

    1994-05-01

    The purpose of the project was to conduct model simulations for past and future climate change with respect to the proposed Yucca Mtn. repository. The authors report on three main topics, one of which is boundary conditions for paleo-hindcast studies. These conditions are necessary for the conduction of three to four model simulations. The boundary conditions have been prepared for future runs. The second topic is (a) comparing the atmospheric general circulation model (GCM) with observations and other GCMs; and (b) development of a better precipitation data base for the Yucca Mtn. region for comparisons with models. These tasks have been completed. The third topic is preliminary assessments of future climate change. Energy balance model (EBM) simulations suggest that the greenhouse effect will likely dominate climate change at Yucca Mtn. for the next 10,000 years. The EBM study should improve rational choice of GCM CO{sub 2} scenarios for future climate change.

  11. Assessing the contribution of natural sources to regional atmospheric mercury budgets

    SciTech Connect

    Gustin, M.S.; Lindberg, S.E.

    1997-12-31

    Contributions to the global atmospheric mercury budget originate from natural and anthropogenic sources. Constraining inputs from anthropogenic point sources has been the emphasis of past research leaving the contribution from diffuse natural and anthropogenic mercury enriched landscapes poorly constrained and underestimated. From September 1--4, 1997 mercury researchers convened in Reno, NV, US to intercompare methods used to determine in situ mercury flux from a naturally enriched landscape. Data collected indicate that naturally mercury-enriched areas constitute a significant atmospheric Hg source term. Mercury fluxes of 30 to 2,000 ng/m{sup 2} h were measured at the Steamboat springs Geothermal Area. These values are one to three orders of magnitude greater than that applied for natural sources in global mercury budgets. Air concentrations measured in the area indicate that natural sources can increase ambient levels above background concentrations. Assessment of these and other data indicate that natural sources constitute a significant source of atmospheric mercury that is available to the global mercury budget, and that the strength of the source is influenced significantly by environmental factors. Determining the contribution of mercury to the atmosphere from diffuse terrestrial sources is necessary to develop local and regional baselines for environmental regulations and risk assessments, and valid emission inventories. A scaling up mercury fluxes measured for diffuse terrestrial surfaces suggests that the natural atmospheric mercury source term in the US is comparable to the anthropogenic source term.

  12. Lichens as indicators of the atmosphere state in the oil exploration district of Tomsk Region

    NASA Astrophysics Data System (ADS)

    Bolshunova, Tatiana; Ivan, Podkozlin

    2013-04-01

    Lichens are widespread in the vegetative cover of West Siberia, particularly in the north. They play an important role in the migration and transformation of chemical pollutants. Lichens lack waxy cuticles and are largely dependent on the atmosphere for their water and nutrient uptake. Lichens are not only studied and used as indicators, but also as accumulators, e.g. for trace and heavy metals. In fact, lichens are known for their ability to accumulate airborne substances to concentrations far greater those in the atmosphere, and the element contents of lichen thalli proved to be directly correlated with environmental levels. Monitoring of the atmosphere pollution using lichens is more efficient than that using snow cover. Because of the long lichen life it is possible to obtain persistent mean characteristics of the ecosystems state. Epiphytic lichens, growing on tree stems are more appropriate to use than that which grow on soil. Epiphytic lichens are more sensitive to changes of the chemical composition of the atmosphere. Pollutants penetrate in the lichen thalli from the atmosphere together with precipitations and dust. Moreover the precipitations are saturated with pollutants when going through crowns of trees and trickling down the steams and branches. Lichen studies are especially important in territories subjected to excessive human activity. Because a great part of Tomsk region (West Siberia, Russia) is the territory of the oil-field exploration, there the atmosphere monitoring is a necessary part of the whole environmental monitoring. The aim of this investigation is the estimation of the influence of oil exploration industry in Tomsk region on the atmosphere by means of the study of epiphytic lichens. Lichen samples were collected in August and September 2010-2011. Sampling net included seven areas distributed inside the oil-exploration districts of Tomsk region. In total 27 samples were collected. In these samples 53 chemical elements were detected by

  13. Biosphere-atmosphere interactions in high-latitude regions

    NASA Astrophysics Data System (ADS)

    Teufel, B. S.; Sushama, L.

    2015-12-01

    The impact of interactive vegetation phenology on land-atmosphere interactions in high-latitude regions is assessed by comparing two pan-arctic simulations of the fifth generation Canadian Regional Climate Model (CRCM5) - one with interactive phenology and the other with prescribed phenology, both driven by ECMWF reanalysis data. Both simulations include soil organic matter and use a deep soil configuration for better representation of permafrost. Interactive phenology is represented in CRCM5 by means of the Canadian Terrestrial Ecosystem Model (CTEM), which is coupled to the Canadian Land Surface Scheme (CLASS). Previous offline simulations of CTEM coupled to CLASS, driven by reanalysis data, show that these models have significant skill in simulating carbon pools and fluxes, as well as permafrost extent and active layer thickness. The performance of the CRCM5 simulations is first assessed by comparing simulated fields, e.g. 2m temperature, precipitation, snow water equivalent, leaf area index, primary productivity, soil carbon and permafrost, to observation-based datasets. The impact of interactive phenology on the simulated land surface and climate is then assessed by focusing on the biophysical feedbacks. The differences in the representation of interannual variability are also analyzed in order to quantify the added value of interactive phenology.

  14. Baltic Sea Ice Regional Indices and their relationship with atmospheric circulation patterns and maritime navigation

    NASA Astrophysics Data System (ADS)

    Sztobryn, M.; Kowalska, B.

    2009-04-01

    The Baltic navigation and urban activities of the coastal communities around the Baltic Sea depended always very much on the ice conditions in the sea. The sea ice occurs different in form and amount, depending on the sea area and the winter season. The aim of the work was the investigation of influence of atmospheric circulation patterns on sea ice condition of Baltic Sea (by the sea ice regional indices). The atmospheric circulation patterns were represented by the German Weather Service's - Grosswetterlagen. The relationship between the ice severity indices and icebreakers activities (number of cases, in which the Swedish and Finnish icebreakers assisted the ships) were investigated. The work was done under the Seaman project (Norwegian Financial Mechanism)

  15. The Influence of Large Solar Proton Events on the Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2012-01-01

    Solar proton events (SPEs) can cause changes in constituents in the Earth s polar middle atmosphere. A number of large SPEs have occurred over the past 50 years and tend to happen most frequently near solar maximum. The highly energetic protons cause ionizations, excitations, dissociations, and dissociative ionizations of the background constituents. Complicated ion chemistry leads to HOx (H, OH, HO2) production and dissociation of N2 leads to NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2) production. Both the HOx and NOy increases can result in changes to ozone in the stratosphere and mesosphere. The HOx increases lead to short-lived (days) ozone decreases in the mesosphere and upper stratosphere. The NOy increases lead to long-lived (several months) stratospheric ozone changes because of the long lifetime of NOy constituents in this region. UARS HALogen Occultation Experiment (HALOE) instrument observations showed SPE-caused polar stratospheric NOx (NO+NO2) increases over 10 ppbv in September 2000 due to the very large SPE of July 2000, which are reasonably well simulated with the Whole Atmosphere Community Climate Model (WACCM). WACCM-computed SPE-caused polar stratospheric ozone decreases >10% continued for up to 5 months past the largest events in the past 50 years, however, SPE-caused total ozone changes were not found to be statistically significant. Small polar middle atmospheric temperature changes of <4 K have also been predicted to occur as a result of the larger SPEs. The polar atmospheric effects of large SPEs during solar cycle 23 and 24 will be emphasized in this presentation.

  16. What can Venus and Mars tell us about Sun's direct influence on Earth's Atmosphere?

    NASA Astrophysics Data System (ADS)

    Lundin, R.

    2010-09-01

    Venus and Mars, Earth's sister planets, are similar but also very different compared to the Earth. The mass-density and surface properties bear certain commonality, but the atmospheric composition, the temperature and the surface pressure on Venus and Mars are very different compared to the Earth. Venus and Mars are arid planets with atmospheres dominated by a greenhouse gas CO2 (>95%), while the Earth's atmosphere is dominated by molecular Nitrogen and Oxygen. The main greenhouse gas in the Earth's atmosphere is water, with a minor contribution of CO2. Bearing these differences in mind, what can we possibly learn from Mars and Venus about the solar influence on the Earth's atmosphere? The answer can be found in how solar forcing affects a planetary atmosphere, more specifically the impact of solar EUV and solar wind variability on a planetary atmosphere. The lack of a strong intrinsic magnetic field on Mars and Venus means that solar wind forcing has a global effect on the upper atmosphere of Mars and Venus. Conversely, the Earth's intrinsic dipole magnetic field alleviates the forcing to narrow zones near the magnetic poles. Results obtained from Venus and Mars orbiters imply that solar wind forcing leads to a long-term gradual removal of atmospheric constituents. New information from ESAs Mars Express and Venus Express orbiters suggests short-term solar wind forcing effects as well, especially in the polar region. While the impact of solar forcing on the "unprotected" planets Venus and Mars seems conceivable, one might argue that similar forcing effects are unlikely on a magnetically protected planet. Short-term "space weather" effects on the Earth's tropospheric circulatory system have been reported in the past, but the effects have usually been discarded using arguments that such a weak forcing is unlikely to have any implications whatsoever on the Earth's weather system. However, considering the forcing observed in e.g. the Venus polar region, solar forcing

  17. Influence of Atmospheric Pressure and Composition on LIBS

    SciTech Connect

    Hatch, Jeremy J.; Scott, Jill R.; Effenberger, A. J. Jr.

    2014-03-01

    Most LIBS experiments are conducted at standard atmospheric pressure in air. However, there are LIBS studies that vary the pressure and composition of the gas. These studies have provided insights into fundamentals of the mechanisms that lead to the emission and methods for improving the quality of LIBS spectra. These atmospheric studies are difficult because the effects of pressure and gas composition and interconnected, making interpretation of the results difficult. The influence of pressures below and above 760 Torr have been explored. Performing LIBS on a surface at reduced pressures (<760 Torr) can result in enhanced spectra due to higher resolution, increased intensity, improved signal-to-noise (S/N), and increased ablation. Lower pressures produce increased resolution because the line width in LIBS spectra is predominantly due to Stark and Doppler broadening. Stark broadening is primarily caused from collisions between electrons and atoms, while Doppler broadening is proportional to the plasma temperature. Close examination using a high resolution spectrometer reveals that spectra show significant peak broadening and self-absorption as pressures increase, especially for pressures >760 Torr. During LIBS plasma expansion, energy is lost to the surrounding atmosphere, which reduces the lifetime of the laser plasma. Therefore, reducing the pressure increases the lifetime of the plasma, allowing more light from the laser plasma to be collected; thus, increasing the observed signal intensity. However, if pressures are too low (<10 Torr), then there is a steep drop in LIBS spectral intensity. This loss in intensity is mostly due to a disordered plasma that results from the lack of sufficient atmosphere to provide adequate confinement. At reduced pressures, the plasma expands into a less dense atmosphere, which results in a less dense shock wave. The reduced density in the shock wave results in reduced plasma shielding, allowing more photons to reach the sample

  18. Development of a reservoir model to improve evapotranspiration estimates in a regional land atmospheric model

    NASA Astrophysics Data System (ADS)

    Voisin, N.; Li, H.; Huang, M.; Leung, L.; Wigmosta, M. S.

    2011-12-01

    The community land model (CLM) was designed for coupling with atmospheric model to simulate the water, energy, and carbon fluxes between the land surface and atmosphere. These fluxes are regulated in various degrees by its hydrologic processes, which have not been vigorously evaluated for applications at watershed or regional scales. In the framework of an integrated regional earth system model being developed, accurate hydrologic information in all of its components including socio-economy, atmosphere, land, and energy infrastructure is needed to represent the interactions between human and earth system processes. Incorporating CLM in this framework requires model evaluation and improvement so that CLM could be used to represent hydrology, soil, managed and unmanaged ecosystems, and biogeochemical processes across scales in a coherent modeling framework. As part of this effort, an irrigation-runoff routing-reservoir model is developed as a relatively simple and generic way to represent water management in CLM, which only deals with natural land surface and hydrologic processes. The objective is to improve evapotranspiration estimates in time and space resulting from human influence, i.e., from irrigation and large reservoir storage. Once fully coupled, it will also allow i) assessing the feedback of increased evapotranspiration in an atmospheric model, ii) investigations of water use and its influence on other human and earth system components. The concept of the preliminary reservoir model is presented over the Columbia River Basin. Challenges due to the differences in time and spatial scales between the physical processes versus reservoir operations and targets (irrigation, flood control, hydropower generation, navigation, environmental flow) are discussed.

  19. Magnetic Field Influence on Atmospheric Escape and Planetary Evolution

    NASA Astrophysics Data System (ADS)

    Driscoll, P. E.; Bercovici, D.

    2012-12-01

    Planetary magnetic fields are maintained by a convective dynamo within the deep interior but their influence extends all the way up to the magnetopause, where the solar wind is deflect around the planet. The presence of a magnetic field is thought to influence the atmosphere-solar wind interaction in a variety of ways, but there is no clear consensus as to whether it impedes or facilitates volatile loss to space. Escape of planetary atmospheres to space is of central importance to studying the evolution of planetary climates, volatile exchange with the interior, and interaction with the space environment. Out of the terrestrial planets Earth has by far the largest surface hydrogen inventory (mainly in the form of liquid water) and furthest magnetopause at ~10 Earth radii. Evidence from volatile concentrations and isotopic ratios imply that Mars and Venus have both lost a significant amount of H over their history, and have maintained little to no magnetic barrier, respectively, to hold off the erosive solar wind. Venus is a particularly interesting case because it is most similar to Earth in mass and density, yet has no detectable magnetic field and an isotopic D/H ratio that implies the loss of a significant amount of water in the past. Is the decline of Venus' dynamo related to the loss of hydrogen from its atmosphere? Is the stability of Earth's unusually large volatile reservoir over billions of years related to the presence of a strong magnetic field over that period of time? We explore conditions under which the presence of a magnetic barrier at the top of the atmosphere may operate as an additional limit to escape. We derive a model for magnetic field limited escape that depends on the terrestrial number density, area, scale height, and loss time scale at the magnetopause. This model predicts rapid escape when magnetic field is weak and magnetopause altitude is low, and a decrease in escape as magnetic field strength increases. This coupling between field

  20. Regional and Global Atmospheric CO2 Measurements Using 1.57 Micron IM-CW Lidar

    NASA Technical Reports Server (NTRS)

    Lin, Bing; Obland, Michael; Nehrir, Amin; Browell, Edward; Harrison, F. Wallace; Dobler, Jeremy; Campbell, Joel; Kooi, Susan; Meadows, Byron; Fan, Tai-Fang; Liu, Zhaoyan

    2015-01-01

    Atmospheric CO2 is a critical forcing for the Earth's climate, and knowledge of its distribution and variations influences predictions of the Earth's future climate. Accurate observations of atmospheric CO2 are also crucial to improving our understanding of CO2 sources, sinks and transports. To meet these science needs, NASA is developing technologies for the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission, which is aimed at global CO2 observations. Meanwhile an airborne investigation of atmospheric CO2 distributions as part of the NASA Suborbital Atmospheric Carbon and Transport â€" America (ACT-America) mission will be conducted with lidar and in situ instrumentation over the central and eastern United States during all four seasons and under a wide range of meteorological conditions. In preparing for the ASCENDS mission, NASA Langley Research Center and Exelis Inc./Harris Corp. have jointly developed and demonstrated the capability of atmospheric CO2 column measurements with an intensity-modulated continuous-wave (IM-CW) lidar. Since 2005, a total of 14 flight campaigns have been conducted. A measurement precision of approx.0.3 ppmv for a 10-s average over desert and vegetated surfaces has been achieved, and the lidar CO2 measurements also agree well with in-situ observations. Significant atmospheric CO2 variations on various spatiotemporal scales have been observed during these campaigns. For example, around 10-ppm CO2 changes were found within free troposphere in a region of about 200A-300 sq km over Iowa during a summer 2014 flight. Results from recent flight campaigns are presented in this paper. The ability to achieve the science objectives of the ASCENDS mission with an IM-CW lidar is also discussed in this paper, along with the plans for the ACT-America aircraft investigation that begins in the winter of 2016.

  1. Soil occupation and atmospheric variations over Sobradinho Lake area. Part two: a regional modeling study

    NASA Astrophysics Data System (ADS)

    Correia, M. F.; da Silva Dias, M. A. F.; da Silva Aragão, M. R.

    2006-11-01

    The impact of the changes on soil cover and land use brought about by the construction of the Sobradinho Dam in the semi-arid region of the São Francisco River Hydrographic Basin is analyzed by means of a numerical model RAMS. Disregarding the influence of a large scale flow, a set of factors were responsible for the creation of a rather complex circulation system that includes mountain-valley winds, lake breeze (LB) and non-conventional circulation all induced by the surface non-homogeneous aspect. Results have demonstrated that the implementation of works of such magnitude brings about environmental changes in an area that stretches far beyond the surroundings of the reservoir. The soil cover alterations due to the ever increasing development of the area with the presence of irrigated crops in a sparsely vegetated region ( caatinga) does affect land surface characteristics, occasioning for that matter the splitting of the available energy into latent and sensible heat fluxes. LB behavior varies in accordance with atmospheric conditions and also in view of the type of vegetation found in the lake surrounding areas. Hydro availability in root zones, even under adverse atmospheric conditions (high temperature and low air humidity) brings up the high rates of evaporation and plant transpiration that contribute towards the increase of humidity and the fall of temperature in lower atmospheric layers.

  2. Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange.

    PubMed

    Alden, Caroline B; Miller, John B; Gatti, Luciana V; Gloor, Manuel M; Guan, Kaiyu; Michalak, Anna M; van der Laan-Luijkx, Ingrid T; Touma, Danielle; Andrews, Arlyn; Basso, Luana S; Correia, Caio S C; Domingues, Lucas G; Joiner, Joanna; Krol, Maarten C; Lyapustin, Alexei I; Peters, Wouter; Shiga, Yoichi P; Thoning, Kirk; van der Velde, Ivar R; van Leeuwen, Thijs T; Yadav, Vineet; Diffenbaugh, Noah S

    2016-10-01

    Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (~1-8 × 10(6)  km(2) ) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub

  3. Regional scale evaporation and the atmospheric boundary layer

    NASA Technical Reports Server (NTRS)

    Parlange, Marc B.; Eichinger, William E.; Albertson, John D.

    1995-01-01

    In this review we briefly summarize some current models of evaporation and the atmospheric boundary layer (ABL) and discuss new experimental and computational oppurtunities that may aid our understanding of evaporation at these larger scales. In particular, consideration is given to remote sensing of the atmosphere, computational fluid dynamics and the role numerical models can play in understanding land-atmosphere interactions. These powerful modeling and measurement tools are allowing us to visualize and study spatial and temporal scales previously untouched, thereby increasing the oppurtunities to improve our understanding of land-atmosphere interaction.

  4. The influence of ionization events on atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.

    1979-01-01

    Atmospheric ionization events can modify the concentration of neutral species in the stratosphere and mesosphere. In particular, ozone is destroyed because of the production of significant quantities of odd nitrogen and hydrogen compounds which react photochemically to destroy ozone. Direct evidence of ozone depletion comes from data taken during and following two solar flares generating large fluxes of 10-100 Mev protons, which bombarded the polar stratosphere and mesosphere. Observations of ozone taken during X-ray emission by solar flares and energetic electron precipitation during aurorae indicates ozone destruction above 50 km by ionization produced odd hydrogen. Lightning is apparently a large contributor to the tropospheric odd nitrogen budget. Ion propulsion induced dumping of the inner proton radiation belt represents a human activity which may influence stratospheric NOx.

  5. Influence of wind direction on pollen concentration in the atmosphere

    NASA Astrophysics Data System (ADS)

    Silva Palacios, I.; Tormo Molina, R.; Muñoz Rodríguez, A. F.

    The daily pollen concentration in the atmosphere of Badajoz (SW Spain) was analysed over a 6-year period (1993-1998) using a volumetric aerobiological trap. The results for the main pollination period are compared with the number of hours of wind each day in the four quadrants: 1 (NE), 2 (SE), 3 (SW) and 4 (NW). The pollen source distribution allowed 16 pollen types to be analysed as a function of their distribution in the four quadrants with respect to the location of the trap. Four of them correspond to species growing in an irrigated farmland environment (Amaranthaceae-Chenopodiaceae, Plantago, Scirpus, and Typha), five to riparian and woodland species (Salix, Fraxinus, Alnus, Populus, and Eucalyptus), four to urban ornamentals (Ulmus, Arecaceae, Cupressaceae, and Casuarina), and three which include the most frequent pollen grains of widely distributed species (Poaceae, Quercus, and Olea). The results show that the distribution of the sources and the wind direction play a very major role in determining the pollen concentration in the atmosphere when these sources are located in certain quadrants, and that the widely distributed pollen sources show no relationship with wind direction. In some years the values of the correlations were not maintained, which leads one to presume that, in order to draw significant conclusions and establish clear patterns of the influence of wind direction, a continuous and more prolonged study will be required.

  6. Factors influencing atmospheric concentrations of polybrominated diphenyl ethers in Japan.

    PubMed

    Dien, Nguyen Thanh; Hirai, Yasuhiro; Miyazaki, Toru; Sakai, Shin-ichi

    2016-02-01

    We used polybrominated diphenyl ether (PBDE) data in air at 38 sites across Japan (2009-2012), which were measured by the Japan Ministry of Environment (JMOE), to elucidate the time trend and seasonality of atmospheric PBDEs. In order to address few (7% for BDE-47) to many (63% for BDE-153 and 183) non-detect data, Tobit model, also called a censored regression model was used. The model revealed that the concentrations of PBDE congeners were influenced by a combination of year, temperature, rainfall rate, and population density. Greater declines were observed for BDE-47, -99, -153 and -183 (-21, -25, -17, -23%/year, p < 0.05) than for BDE-209 (-6%/year, p = 0.065). These trends were consistent with the estimated trends of penta-, octa- and deca-BDE contained in in-use products based on domestic demand for PBDEs in Japan and product lifespan. Seasonal patterns were opposite for light congeners (BDE-47 and -99), which increased with temperature, and heavy congeners (BDE-183, and -209), which decreased with temperature. Temperature-dependent emission (evaporation) for light congeners and temperature-independent emission (abrasion) for heavy congeners, coupled with seasonality of atmospheric boundary layer height, might explain these seasonal patterns. Human population density showed a positive correlation with all PBDE congener concentrations, whereas PBDEs showed negative correlation with rainfall rate.

  7. An investigation of aerosol optical properties: Atmospheric implications and influences

    NASA Astrophysics Data System (ADS)

    Penaloza-Murillo, Marcos A.

    An experimental, observational, and theoretical investigation of aerosol optical properties has been made in this work to study their implications and influences on the atmosphere. In the laboratory the scientific and instrumental methodology consisted of three parts, namely, aerosol generation, optical and mass concentration measurements, and computational calculations. In particular the optical properties of ammonium sulfate and caffeine aerosol were derived from measurements made with a transmissometer cell-reciprocal- integrating nephelometer (TCRIN), equipped with a laser beam at 632.8 nm, and by applying a Mie theory computer code The aerosol generators, optical equipment and calibration procedures were reviewed. The aerosol shape and size distribution were studied by means of scanning electron microscopy and the Gumprecht- Sliepcevich/Lipofsky-Green extinction-sedimentation method. In particular the spherical and cylindrical shape were considered. During this investigation, an alternative method for obtaining the optical properties of monodisperse spherical non-absorbing aerosol using a cell-transmissometer, which is based on a linearisation of the Lambert-Beer law, was found. In addition, adapting the TCRIN to electrooptical aerosol studies, the optical properties of a circular-cylindrical aerosol of caffeine were undertaken under the condition of random orientation in relation with the laser beam, and perpendicular orientation to it. A theoretical study was conducted to assess the sensitivity of aerosol to a change of shape under different polarisation modes. The aerosol optical properties, obtained previously in the laboratory, were then used to simulate the direct radiative forcing. The calculations and results were obtained by applying a one- dimensional energy-balance box model. The influence of atmospheric aerosol on the sky brightness due to a total solar eclipse was studied using the photometric and meteorological observations made during the

  8. Influence of seasonal cycles in Martian atmosphere on entry, descent and landing sequence

    NASA Astrophysics Data System (ADS)

    Marčeta, Dušan; Šegan, Stevo; Rašuo, Boško

    2014-05-01

    The phenomena like high eccentricity of Martian orbit, obliquity of the orbital plane and close alignment of the winter solstice and the orbital perihelion, separately or together can significantly alter not only the level of some Martian atmospheric parameters but also the characteristics of its diurnal and seasonal cycle. Considering that entry, descent and landing (EDL) sequence is mainly driven by the density profile of the atmosphere and aerodynamic characteristic of the entry vehicle. We have performed the analysis of the influence of the seasonal cycles of the atmospheric parameters on EDL profiles by using Mars Global Reference Atmospheric Model (Mars-GRAM). Since the height of the deployment of the parachute and the time passed from the deployment to propulsion firing (descent time) are of crucial importance for safe landing and the achievable landing site elevation we paid special attention to the influence of the areocentric longitude of the Sun (Ls) on these variables. We have found that these variables have periodic variability with respect to Ls and can be very well approximated with a sine wave function whose mean value depends only on the landing site elevation while the amplitudes and phases depend only on the landing site latitude. The amplitudes exhibit behavior which is symmetric with respect to the latitude but the symmetry is shifted from the equator to the northern mid-tropics. We have also noticed that the strong temperature inversions which are usual for middle and higher northern latitudes while Mars is around its orbital perihelion significantly alter the descent time without influencing the height of the parachute deployment. At last, we applied our model to determine the dependence of the accessible landing region on Ls and found that this region reaches maximum when Mars is around the orbital perihelion and can vary 50° in latitude throughout the Martian year.

  9. Seasonal emanation of radon at Ghuttu, northwest Himalaya: Differentiation of atmospheric temperature and pressure influences.

    PubMed

    Kamra, Leena

    2015-11-01

    Continuous monitoring of radon along with meteorological parameters has been carried out in a seismically active area of Garhwal region, northwest Himalaya, within the frame work of earthquake precursory research. Radon measurements are carried out by using a gamma ray detector installed in the air column at a depth of 10m in a 68m deep borehole. The analysis of long time series for 2006-2012 shows strong seasonal variability masked by diurnal and multi-day variations. Isolation of a seasonal cycle by minimising short-time by 31 day running average shows a strong seasonal variation with unambiguous dependence on atmospheric temperature and pressure. The seasonal characteristics of radon concentrations are positively correlated to atmospheric temperature (R=0.95) and negatively correlated to atmospheric pressure (R=-0.82). The temperature and pressure variation in their annual progressions are negatively correlated. The calculations of partial correlation coefficient permit us to conclude that atmospheric temperature plays a dominant role in controlling the variability of radon in borehole, 71% of the variability in radon arises from the variation in atmospheric temperature and about 6% of the variability is contributed by atmospheric pressure. The influence of pressure variations in an annual cycle appears to be a pseudo-effect, resulting from the negative correlation between temperature and pressure variations. Incorporation of these results explains the varying and even contradictory claims regarding the influence of the pressure variability on radon changes in the published literature. Temperature dependence, facilitated by the temperature gradient in the borehole, controls the transportation of radon from the deep interior to the surface.

  10. Natural sources of atmospheric aerosols influencing air quality across Europe.

    PubMed

    Viana, M; Pey, J; Querol, X; Alastuey, A; de Leeuw, F; Lükewille, Anke

    2014-02-15

    Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2 μg/m(3) in Italy, France and Portugal, between 1 and 4 μg/m(3) in Spain (10 μg/m(3) when including the Canary Islands), 5 μg/m(3) in UK, between 3 and 8 μg/m(3) in Greece, and reached up to 13 μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe. PMID:24342088

  11. Influence of the Laurentian Great Lakes on Regional Climate

    NASA Astrophysics Data System (ADS)

    Notaro, M.; Holman, K.; Zarrin, A.; Fluck, E.; Vavrus, S. J.; Bennington, V.

    2012-12-01

    The influence of the Laurentian Great Lakes on climate is assessed by comparing two decade-long simulations, with the lakes either included or excluded, using the Abdus Salam International Centre for Theoretical Physics Regional Climate Model Version 4. The Great Lakes dampen the variability in near-surface air temperature across the surrounding region, while reducing the amplitude of the diurnal cycle and annual cycle of air temperature. The impacts of the Great Lakes on the regional surface energy budget include an increase (decrease) in turbulent fluxes during the cold (warm) season and an increase in surface downward shortwave radiation flux during summer due to diminished atmospheric moisture and convective cloud amount. Changes in the hydrologic budget due to the presence of the Great Lakes include increases in evaporation and precipitation during October-March and decreases during May-August, along with springtime reductions in snowmelt-related runoff. Circulation responses consist of a regionwide decrease in sea-level pressure in autumn-winter and an increase in summer, with enhanced ascent and descent in the two seasons, respectively. The most pronounced simulated impact of the Great Lakes on synoptic systems traversing the basin is a weakening of cold-season anticyclones.

  12. Influence of atmospheric stability on wind-turbine wakes: A large-eddy simulation study

    NASA Astrophysics Data System (ADS)

    Abkar, Mahdi; Porté-Agel, Fernando

    2014-05-01

    In this study, large-eddy simulation is combined with a turbine model to investigate the influence of atmospheric stability on wind-turbine wakes. In the simulations, subgrid-scale turbulent fluxes are parameterized using tuning-free Lagrangian scale-dependent dynamic models. These models optimize the local value of the model coefficients based on the dynamics of the resolved scales. The turbine-induced forces are parameterized with an actuator-disk model with rotation. In this technique, blade-element theory is used to calculate the lift and drag forces acting on the blades. Emphasis is placed on the structure and characteristics of wind-turbine wakes in the cases where the incident flows to the turbine have the same mean velocity at the hub height but different stability conditions. The simulation results show that atmospheric stability has a significant effect on the spatial distribution of the mean velocity deficit and turbulent fluxes in the wake region. In particular, the magnitude of the velocity deficit increases with increasing stability in the atmosphere. In addition, the locations of the maximum turbulence intensity and turbulent stresses are closer to the turbine in convective boundary layer compared with neutral and stable ones. Detailed analysis of the resolved turbulent kinetic energy (TKE) budget inside the wake reveals also that the thermal stratification of the incoming wind considerably affects the magnitude and spatial distribution of the turbulent production, transport term and dissipation rate (transfer of energy to the subgrid scales). It is also shown that the near-wake region can be extended to a farther distance downstream in stable condition compared with neutral and unstable counterparts. In order to isolate the effect of atmospheric stability, additional simulations of neutrally-stratified atmospheric boundary layers are performed with the same turbulence intensity at hub height as convective and stable ones. The results show that the

  13. Atmospheric emitted radiance interferometer (AERI): Status and the aerosol explanation for extra window region emissions

    SciTech Connect

    Revercomb, H.E.; Knuteson, R.O.; Best, F.A.; Dirkx, T.P.

    1996-04-01

    High spectral resolution observations of downwelling emission from 3 to 19 microns have been made by the Atmospheric Emitted Radiance Interferometer (AERI) Prototype at the Southern Great Plains (SGP) Cloud and Radiative Testbed (CART) site for over two years. The spectral data set from AERI provides a basis for improving clear sky radiative transfer; determining the radiative impact of clouds, including the derivation of cloud radiative properties; defining the influences of aerosols in the window regions; and retrieving boundary layer state properties, including temperature, water vapor, and other trace gases. The data stream of radiometrically and spectrally calibrated radiances is routinely provided by Pacific Northwest Laboratory (PNL) to those science teams requesting it, and further information on the instrument and data characteristics is available in the ARM Science Team proceedings for 1993 and 1994 and in several conference publications. This paper describes the AERI status, calibration, field experiment wit a new AERI-01 and schedule, window region emissions, and future AERI plans.

  14. Regional Feedbacks Between the Ocean and the Atmosphere in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Thompson, L.; Garcia, M.; Kelly, K. A.; Booth, J. F.

    2012-12-01

    The ocean acts to buffer changes in the climate system with the upper 800m of the ocean taking up more than 90% of the excess heat in the climate system. On interannual time scales, surface heat fluxes damp the low-frequency heat content anomalies in some areas of the ocean where heat anomalies can be released back to the atmosphere. Analysis of satellite altimetry observations of SSH (sea surface height) as a proxy for upper ocean heat content and net suface heat flux from OAFlux (Objectively Analyzed air-sea fluxes) 993-2009 allows the identification of the times of the year and the locations in the North Atlantic where heat content anomalies are driving surface fluxes. Heat content has six month persistence while surface flux has at most one month persistence. Times series for each month of the year at each location are created to examine the lagged correlation between upper ocean heat content and the net surface heat fluxes. The heat content anomalies south of the Gulf Stream in June through November are negatively correlated with surface fluxes in November with a warmer ocean leading to surface fluxes out of the ocean. In this region, the mixed-layer by November reaches 100 m and the previous summer's stored heat is accessible to the atmosphere. The high correlations continue into December and January. By February, the correlation is no longer significant. In the region between 15N and 40N off the coast of Africa, January through May heat content are anti-correlated with surface fluxes in May. In May at this location, the climatological sensible heat flux is into the ocean, the planetary boundary layer is stable and stratocumulus clouds are common. Significant correlations in the summer are also found in the central subpolar North Atlantic. This analysis suggests that locally ocean heat content anomalies can feedback to the atmosphere, but only during certain times of the year. The impact on the atmosphere in late fall and early winter can influence of the

  15. The impacts of precipitation on land- atmosphere interaction over the semi-arid Loess Plateau region

    NASA Astrophysics Data System (ADS)

    WANG, G.; Huang, J.

    2015-12-01

    To understand the impacts of precipitation on land-atmosphere interactions over semi-arid regions, 6-year continuous measurements data in situ were analyzed to investigate the influence of precipitation on soil moisture, evapotranspiration, energy partitioning and plant growing over Loess Plateau in northwest China. Results show that annual precipitation had obvious inter-annual variability, and the variation of soil moisture; evaporation and CO2 flux were very consistently with the annual cycle and intensity of precipitation. Soil moisture is the key participant in land-atmosphere interaction. However, as the water shortage and disconnected from water table over the semi-arid region, it is much more sensitive with precipitation compensation and evaporation feedbacks. Soil water can cooling the near surface air temperature by evaporation (latent heat flux), and also as the main energy partitioning consumer of net radiation in humid area or pluvial period in arid area, yet it was water limited in arid and semi-arid region, sensible heat flux predominated net radiation for enhancing the surface air temperature. We also found that soil moisture profile significantly affected the plant physiology, which was also consistent with the annual cycle and intensity of precipitation.

  16. Temporal variability of atmospheric turbidity and DNI attenuation in the sugarcane region, Botucatu/SP

    NASA Astrophysics Data System (ADS)

    Santos, Cícero Manoel dos; Escobedo, João Francisco

    2016-11-01

    In this study, attenuation of direct normal solar irradiance (DNI) in Botucatu / São Paulo, an area under the influence of local and adjacent agricultural burning, is expressed using the Linke's turbidity factor (TL) in the period from 1996 to 2008. Two methodologies represented as TLDj and TLLi were used. Temporal variability (hourly average for the season and monthly average) is presented. Turbidity was correlated with wind speed and air temperature. Frequency distribution and cumulative frequency are analyzed to determine turbidity predominance levels in the local atmosphere. Optical depth information of aerosols at 550 nm (AOD550nm) and water vapor were obtained by the Terra satellite using the MODIS sensor. The highest degree of DNI transmission is observed in the morning. Close to solar noon, transmission is smaller (greatest TL value). Diurnal TL variability is more evident in the hot period than in the cold period. May and June were the months of lowest DNI attenuation (highest atmospheric transparency). The highest DNI attenuation occurs in spring (TLDj = 4.22 ± 0.05 and TLLi = 4.65 ± 0.06) and summer (TLDj = 4.27 ± 0.14 and TLLi = 4.69 ± 0.15). Wind speed and air temperature were positively correlated with TL. In > 28% of hours of clear sky, turbidity exceeded the value of 4.0. The region of Botucatu seems to be influenced by water vapor and aerosols from different origins. This study concludes that these factors significantly reduce DNI incidence on the surface, with higher atmospheric transparency in the cold period and lower atmospheric transparency in the warm period.

  17. The Deuterium Excess in Precipitation and Atmospheric Moisture in the Southern Great Plains Region of USA

    NASA Astrophysics Data System (ADS)

    Machavaram, M. V.; Conrad, M. E.; Miller, N. L.

    2002-12-01

    Systematic study of variations in the isotopic ratios of oxygen and hydrogen in various components of the water cycle is helpful for understanding local and regional hydro-climatology. The relationship between the isotopic ratios of oxygen and hydrogen in precipitation, defined as the Meteoric Water Line (MWL) yields valuable information about the climatic factors and secondary moisture sources which influence the precipitation process, when compared with global MWL(δD = 8*δ18O + 10). It is estimated that a significant portion of precipitation on land is a result of evapo-transpired moisture that is recycled in the atmosphere. In order to understand the response of regional water cycles to climatic variations, it is important to quantify the influence of locally derived moisture on precipitation. The Deuterium Excess (defined as: d = δD - 8*δ18O) in precipitation is a valuable tool for estimating the contribution of such secondary moisture sources to precipitation. As part of the DOE Water Cycle Pilot Study to improve predictability in part by integrating stable isotope variations in to climatological models, atmospheric vapor samples were collected in the southern Great Plains region. Vapor samples were collected at the surface and between 900 and 5000 meters(msl) and were analyzed for their δD and δ18O values. The δD and δ18O of the vapor samples showed a progressive depletion with increasing altitude. The samples collected below the Atmospheric Boundary Layer (ABL) showed a remarkable increase in the d-excess (19‰ ) compared to the sample above the ABL (4‰ ). Precipitation samples collected in 1999 from the National Atmospheric Deposition Program (NADP) stations in Texas and Oklahoma were also analyzed for their stable isotope values. The precipitation in the inland station of Oklahoma is characterized by higher d-excess than that of the coastal Texas station. Such higher d-excess is shown to result from an admixture of locally evapo

  18. The Anthropogenic Influence on Atmospheric Carbonyl Sulfide: Implications for Inverse Analysis of Process-Level Carbon Cycle Fluxes

    NASA Astrophysics Data System (ADS)

    Zumkehr, A. L.; Hilton, T. W.; Whelan, M.; Smith, S. J.; Campbell, J. E.

    2014-12-01

    Carbonyl sulfide (COS) is the most abundant sulfur containing gas in the troposphere and a significant precursor to stratospheric aerosol. Recent insights on the plant uptake of atmospheric COS suggest that plant uptake is the largest component of the global COS budget and that COS may provide a powerful new tool for partitioning sources and sinks of atmospheric CO2 at regional to global scales. However, alternative sources and sinks of COS must also be accounted for to minimize the uncertainty of this carbon cycle tracer approach. Here we focus on direct and indirect sources of atmospheric COS from anthropogenic activities. We construct bottom-up gridded inventories of anthropogenic COS sources and compare these to previous estimates that were based on relatively sparse emissions data. Furthermore, we simulate COS concentrations with an regional atmospheric chemistry model to show the influence of these alternative source estimates in relation to plant uptake at a range of surface and airborne monitoring sites.

  19. Rare earth element components in atmospheric particulates in the Bayan Obo mine region.

    PubMed

    Wang, Lingqing; Liang, Tao; Zhang, Qian; Li, Kexin

    2014-05-01

    The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM10) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m(3), and those for PM10 were 42.8 and 68.9 ng/m(3), in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM10 and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM10 were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La(N)/Yb(N), La(N)/Sm(N), Gd(N)/Yb(N)).

  20. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years

    PubMed Central

    Han, Y. M.; Wei, C.; Huang, R.-J.; Bandowe, B. A. M.; Ho, S. S. H.; Cao, J. J.; Jin, Z. D.; Xu, B. Q.; Gao, S. P.; Tie, X. X.; An, Z. S.; Wilcke, W.

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People’s Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980–2012 relative to the period 1850–1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas. PMID:26750586

  1. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years.

    PubMed

    Han, Y M; Wei, C; Huang, R-J; Bandowe, B A M; Ho, S S H; Cao, J J; Jin, Z D; Xu, B Q; Gao, S P; Tie, X X; An, Z S; Wilcke, W

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People's Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980-2012 relative to the period 1850-1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas. PMID:26750586

  2. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years

    NASA Astrophysics Data System (ADS)

    Han, Y. M.; Wei, C.; Huang, R.-J.; Bandowe, B. A. M.; Ho, S. S. H.; Cao, J. J.; Jin, Z. D.; Xu, B. Q.; Gao, S. P.; Tie, X. X.; An, Z. S.; Wilcke, W.

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People’s Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980-2012 relative to the period 1850-1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas.

  3. The Long-term Middle Atmospheric Influence of Very Large Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Randall, Cora E.; Fleming, Eric L.; Frith, Stacey M.

    2008-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. The humankind or anthropogenic influence on ozone originates from the chlorofluorocarbons and halons (chlorine and bromine) and has led to international regulations greatly limiting the release of these substances. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the long-term (> few months) influences of solar proton events from 1963 through 2004 on stratospheric ozone and temperature. There were extremely large solar proton events in 1972, 1989,2000,2001, and 2003. These events caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen-containing compounds, which led to the polar ozone destruction. The nitrogen-containing compounds, called odd nitrogen, lasted much longer than the hydrogen-containing compounds and led to long-lived stratospheric impacts. An extremely active period for these events occurred in the five-year period, 2000- 2004, and caused increases in odd nitrogen which lasted for several months after individual events. Associated stratospheric ozone decreases of >lo% were calculated

  4. A study of the influence of forest gaps on fire-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Kiefer, Michael T.; Heilman, Warren E.; Zhong, Shiyuan; Charney, Joseph J.; Bian, Xindi

    2016-07-01

    Much uncertainty exists regarding the possible role that gaps in forest canopies play in modulating fire-atmosphere interactions in otherwise horizontally homogeneous forests. This study examines the influence of gaps in forest canopies on atmospheric perturbations induced by a low-intensity fire using the ARPS-CANOPY model, a version of the Advanced Regional Prediction System (ARPS) model with a canopy parameterization. A series of numerical experiments are conducted with a stationary low-intensity fire, represented in the model as a line of enhanced surface sensible heat flux. Experiments are conducted with and without forest gaps, and with gaps in different positions relative to the fire line. For each of the four cases considered, an additional simulation is performed without the fire to facilitate comparison of the fire-perturbed atmosphere and the background state. Analyses of both mean and instantaneous wind velocity, turbulent kinetic energy, air temperature, and turbulent mixing of heat are presented in order to examine the fire-perturbed atmosphere on multiple timescales. Results of the analyses indicate that the impact of the fire on the atmosphere is greatest in the case with the gap centered on the fire and weakest in the case with the gap upstream of the fire. It is shown that gaps in forest canopies have the potential to play a role in the vertical as well as horizontal transport of heat away from the fire. Results also suggest that, in order to understand how the fire will alter wind and turbulence in a heterogeneous forest, one needs to first understand how the forest heterogeneity itself influences the wind and turbulence fields without the fire.

  5. Two centuries of observed atmospheric variability and change over the North Sea region

    NASA Astrophysics Data System (ADS)

    Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard; Woollings, Tim

    2016-04-01

    In the upcoming North Sea Region Climate Change Assessment (NOSCCA), we present a synthesis of current knowledge about past, present and possible future climate change in the North Sea region. A climate change assessment from published scientific work has been conducted as a kind of regional IPCC report, and a book has been produced that will be published by Springer in 2016. In the framework of the NOSCCA project, we examine past and present studies of variability and changes in atmospheric variables within the North Sea region over the instrumental period, roughly the past 200 years, based on observations and reanalyses. The variables addressed in this presentation are large-scale circulation, pressure and wind, surface air temperature, precipitation and radiative properties (clouds, solar radiation, and sunshine duration). While air temperature over land, not unexpectedly, has increased everywhere in the North Sea region, with strongest trends in spring and in the north of the region, a precipitation increase has been observed in the north and a decrease in the south of the region. This pattern goes along with a north-eastward shift of storm tracks and is in agreement with climate model projections under enhanced greenhouse gas concentrations. For other variables, it is not obvious which part of the observed changes may be due to anthropogenic activities and which is internally forced. It remains also unclear to what extent atmospheric circulation over the North Sea region is influenced by distant factors, in particular Arctic sea-ice decline in recent decades. There are indications of an increase in the number of deep cyclones (but not in the total number of cyclones), while storminess since the late 19th century shows no robust trends. The persistence of circulation types appears to have increased over the last century, and consequently, there is an indication for 'more extreme' extreme events. However, changes in extreme weather events are difficult to assess

  6. REGIONAL MODELING OF THE ATMOSPHERIC TRANSPORT AND DEPOSITION OF ATRAZINE

    EPA Science Inventory

    A version of the Community Multiscale Air Quality (CMAQ) model has been developed by the U.S. EPA that is capable of addressing the atmospheric fate, transport and deposition of some common trace toxics. An initial, 36-km rectangular grid-cell application for atrazine has been...

  7. Investigating the atmospheric energy spectra using ECMWF analysis: Regional dependence

    NASA Astrophysics Data System (ADS)

    Mukherjee, P.; Zhang, M.

    2010-12-01

    The atmospheric turbulence energy spectrum has been a subject of active research for a long time. Beginning with Kolmogorov’s theory of three-dimensional turbulence, to Kraichnan’s two-dimensional turbulence and its extension to the quasi-geostrophic case by Charney, various theoretical models and hypothesis have tried to explain the energy spectrum slope. However, the success or failure of a theory can only be gauged by comparing its output with actual observational data. Nastrom and Gage were able to do just that by analyzing thousands of flight observation data and plotting the wave number spectra of wind and temperature in 1980’s. But, the flight data was confined only to the upper atmosphere and mostly mid-latitudes of northern hemisphere. We use the high-resolution ECMWF analysis data, as a part of Year of Tropical Convection (YOTC) to study the atmospheric energy spectra over a wide range of conditions. We compared and interpreted the differences of the atmospheric energy spectra in the tropics and mid-latitudes, in the winter (DJF) and summer (JJA), at the surface and in the upper troposphere. Our results conform to the previously observed -3 power law for mid-latitude data in the upper troposphere, but the slope of the energy spectrum from the surface wind data and for the tropics exhibited quite different shapes. The causes of these differences are discussed.

  8. Medicanes in an ocean-atmosphere coupled regional climate model

    NASA Astrophysics Data System (ADS)

    Akhtar, N.; Brauch, J.; Dobler, A.; Béranger, K.; Ahrens, B.

    2014-03-01

    So-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and warm-core Mediterranean cyclones that exhibit some similarities to tropical cyclones. The strong cyclonic winds associated with medicanes threaten the highly populated coastal areas around the Mediterranean basin. To reduce the risk of casualties and overall negative impacts, it is important to improve the understanding of medicanes with the use of numerical models. In this study, we employ an atmospheric limited-area model (COSMO-CLM) coupled with a one-dimensional ocean model (1-D NEMO-MED12) to simulate medicanes. The aim of this study is to assess the robustness of the coupled model in simulating these extreme events. For this purpose, 11 historical medicane events are simulated using the atmosphere-only model, COSMO-CLM, and coupled model, with different setups (horizontal atmospheric grid-spacings of 0.44°, 0.22°, and 0.08°; with/without spectral nudging, and an ocean grid-spacing of 1/12°). The results show that at high-resolution, the coupled model is able to not only simulate most of medicane events but also improve the track length, core temperature, and wind speed of simulated medicanes compared to the atmosphere-only simulations. The results suggest that the coupled model is more proficient for systemic and detailed studies of historical medicane events, and that this model can be an effective tool for future projections.

  9. Medicanes in an ocean-atmosphere coupled regional climate model

    NASA Astrophysics Data System (ADS)

    Akhtar, N.; Brauch, J.; Dobler, A.; Béranger, K.; Ahrens, B.

    2014-08-01

    So-called medicanes (Mediterranean hurricanes) are meso-scale, marine, and warm-core Mediterranean cyclones that exhibit some similarities to tropical cyclones. The strong cyclonic winds associated with medicanes threaten the highly populated coastal areas around the Mediterranean basin. To reduce the risk of casualties and overall negative impacts, it is important to improve the understanding of medicanes with the use of numerical models. In this study, we employ an atmospheric limited-area model (COSMO-CLM) coupled with a one-dimensional ocean model (1-D NEMO-MED12) to simulate medicanes. The aim of this study is to assess the robustness of the coupled model in simulating these extreme events. For this purpose, 11 historical medicane events are simulated using the atmosphere-only model, COSMO-CLM, and coupled model, with different setups (horizontal atmospheric grid spacings of 0.44, 0.22, and 0.08°; with/without spectral nudging, and an ocean grid spacing of 1/12°). The results show that at high resolution, the coupled model is able to not only simulate most of medicane events but also improve the track length, core temperature, and wind speed of simulated medicanes compared to the atmosphere-only simulations. The results suggest that the coupled model is more proficient for systemic and detailed studies of historical medicane events, and that this model can be an effective tool for future projections.

  10. Rare earth element components in atmospheric particulates in the Bayan Obo mine region

    SciTech Connect

    Wang, Lingqing Liang, Tao Zhang, Qian; Li, Kexin

    2014-05-01

    The Bayan Obo mine, located in Inner Mongolia, China, is the largest light rare earth body ever found in the world. The research for rare earth elements (REEs) enrichment in atmospheric particulates caused by mining and ore processing is fairly limited so far. In this paper, atmospheric particulates including total suspended particulate (TSP) matter and particles with an equivalent aerodynamic diameter less than 10 μm (PM{sub 10}) were collected around the Bayan Obo mine region, in August 2012 and March 2013, to analyze the levels and distributions of REEs in particles. The total concentrations of REEs for TSP were 149.8 and 239.6 ng/m{sup 3}, and those for PM{sub 10} were 42.8 and 68.9 ng/m{sup 3}, in August 2012 and March 2013, respectively. Enrichment factor was calculated for all 14 REEs in the TSP and PM{sub 10} and the results indicated that REEs enrichment in atmosphere particulates was caused by anthropogenic sources and influenced by the strong wind in springtime. The spatial distribution of REEs in TSP showed a strong gradient concentration in the prevailing wind direction. REE chondrite normalized patterns of TSP and PM{sub 10} were similar and the normalized curves inclined to the right side, showing the conspicuous fractionation between the light REEs and heavy REE, which supported by the chondrite normalized concentration ratios calculated for selected elements (La{sub N}/Yb{sub N}, La{sub N}/Sm{sub N}, Gd{sub N}/Yb{sub N}). - Highlights: • TSP and PM{sub 10} samples were collected to analyze the levels and distributions of REE. • Enrichment factors indicated that REE enrichment was caused by anthropogenic sources. • The distribution of REEs showed a strong gradient in the prevailing wind direction. • Obvious fractionation between LREEs and HREEs is observed in atmospheric particulates.

  11. Two centuries of observed atmospheric variability and change over the North Sea region

    NASA Astrophysics Data System (ADS)

    Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; van Oldenborgh, Geert Jan; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard

    2015-04-01

    Situated in northwestern Europe, the North Sea region is under influence of air masses from subtropical to arctic origin, and thus exhibits significant natural climate variability. As the land areas surrounding the North Sea are densely populated, climate change is an important issue in terms of e.g. coastal protection, fishery and trade. This study is part of the NOSCCA initiative (North Sea Region Climate Change Assessment) and presents observed variability and changes in atmospheric parameters during the last roughly 200 years. Circulation patterns show considerable decadal variability. In recent decades, a northward shift of storm tracks and increased cyclonic activity has been observed. There is also an indication of increased persistence of weather types. The wind climate is dominated by large multidecadal variability, and no robust long-term trends can be identified in the available datasets. There is a clear positive trend in near-surface temperatures, in particular during spring and winter. Over the region as a whole, no clear long-term precipitation trends are visible, although regional indications exist for an increased risk of extreme precipitation events.

  12. Influence of Industrialization in the Campinas Rural Region.

    ERIC Educational Resources Information Center

    Ferrari, Alfonso Trujillo

    The Campinas region of Brazil was studied to determine if the introduction of industrial plants in rural areas influenced the life of the rural population. The purpose of this study was to obtain an insight into the manner by which the industrialization influence is functioning in the Campinas rural area. The region and its rural population were…

  13. On validation of regional atmosphere and wave models for the Black Sea region

    NASA Astrophysics Data System (ADS)

    Dulov, Vladimir; Shokurov, Mikhail; Chechina, Katerina; Soukissian, Takvor; Malinovsky, Vladimir

    2014-05-01

    Mesoscale atmospheric models MM5 and WRF adapted to the Black Sea region in Marine Hydrophysical Institute (MHI, National Academy of Sciences of Ukraine) together with wave model WAM are widely using in the last decade. Black Sea meteorological and wave climate assessing, 3-5 days operational forecast, researches of various physical phenomena typical for the Black Sea coastal zone are examples of application of such regional model calculations. Therefore we made some inspection of their quality. Results of operational regional forecast of catastrophic weather events in the Black Sea region are considered. Flooding of 6-7 July 2012 in the Krasnodar Region, Russia caused a loss of more than 170 lives and huge economic damage. Hazardous storm of 11 November 2007 near the Crimean coast caused accidents and sinks of many vessels including ones carrying fuel oil and sulfur, more than 20 members of the crews were missing and severe ecological damage was suffered. However, the forecast of rainfall intensity had appeared five days before the flood at free access on the Internet website http://vao.hydrophys.org and the forecast of the wave height appeared on the same website three days before the storm. Quality of the regional forecast and its advantages over the global forecast are discussed. In situ wave data including 2D wave spectra obtained at the MHI Black Sea Research Platform in 2012-2013 over all seasons were compared with model calculations. The distance of the Platform to the shore is 0.5 km where the sea depth is 28 m. Only part of wave spectrum belonging to wave frequencies lower than 0.4 Hz was considered to filter out waves developing from the coastal line. It is concluded that scatter indexes for modeled significant wave height and mean frequency are about of 50% and 15%. Some systematic defects of model calculations are revealed but the use of the model-based forecasts could lead to significant reduction in human losses and economic damage from catastrophic

  14. Influence of meteor showers on Earth's upper atmosphere temperature

    NASA Astrophysics Data System (ADS)

    Salivonov, A.; Kozak, L.

    2005-04-01

    The warming of night atmosphere of the Earth during action of meteor showers is analyzed. It was used a satellite measurements in Earth's upper atmosphere for the period of 1993 in height range 85-130 km. Temperature values were obtained with the help of device WINDII (Wind Imaging Interferometer) installed on the America-French satellite UARS (Upper Atmosphere Research Satellite). The most intensive meteor showers Perseids, Leonids, Orionids and Geminids were considered.

  15. Internal wave activity in the polar atmospheric regions during 2006 - 2009 revealed by COSMIC radio occultation data

    NASA Astrophysics Data System (ADS)

    Kirillovich, Ivan; Gubenko, Vladimir; Pavelyev, Alexander; Liou, Yuei-An

    ) and Scandinavian Peninsula. In this work, the results of an analysis of the wave activity and factors influencing upon it in the polar stratosphere of Arctic and Antarctic have been presented and discussed. A statistical analysis of the IGW activity in Polar Regions (latitudes more than 60º) of the Earth’s atmosphere using Formosat-3/COSMIC RO temperature data collected from July 2006 to March 2009 is performed. Geographic and seasonal distributions of the IGW potential energy per unit mass (wave activity indicator) in the altitude interval from 15 to 35 km are determined and analyzed. This work was partially supported by the RFBR grant 13-02-00526-а and Program 22 of the RAS Presidium.

  16. A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry MechanismsChemistry Mechanisms

    EPA Science Inventory

    We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RAC...

  17. Using Search Algorithms and Probabilistic Graphical Models to Understand the Influence of Atmospheric Circulation on Western US Drought

    NASA Astrophysics Data System (ADS)

    Malevich, S. B.; Woodhouse, C. A.

    2015-12-01

    This work explores a new approach to quantify cool-season mid-latitude circulation dynamics as they relate western US streamflow variability and drought. This information is used to probabilistically associate patterns of synoptic atmospheric circulation with spatial patterns of drought in western US streamflow. Cool-season storms transport moisture from the Pacific Ocean and are a primary source for western US streamflow. Studies overthe past several decades have emphasized that the western US hydroclimate is influenced by the intensity and phasing of ocean and atmosphere dynamics and teleconnections, such as ENSO and North Pacific variability. These complex interactions are realized in atmospheric circulation along the west coast of North America. The region's atmospheric circulation can encourage a preferential flow in winter storm tracks from the Pacific, and thus influence the moisture conditions of a given river basin over the course of the cool season. These dynamics have traditionally been measured with atmospheric indices based on values from fixed points in space or principal component loadings. This study uses collective search agents to quantify the position and intensity of potentially non-stationary atmosphere features in climate reanalysis datasets, relative to regional hydrology. Results underline the spatio-temporal relationship between semi-permanent atmosphere characteristics and naturalized streamflow from major river basins of the western US. A probabilistic graphical model quantifies this relationship while accounting for uncertainty from noisy climate processes, and eventually, limitations from dataset length. This creates probabilities for semi-permanent atmosphere features which we hope to associate with extreme droughts of the paleo record, based on our understanding of atmosphere-streamflow relations observed in the instrumental record.

  18. Mesoscale Modeling of Water Vapor and Dust in Valles Marineris: Atmospheric Influences on Recurring Slope Lineae.

    NASA Astrophysics Data System (ADS)

    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

  19. Regional Assimilation of NASA Atmospheric Infrared Sounder (AIRS) Data

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Lapenta, William; Jediovec, Gary J.; McCarty, William; Mecikalski, John R.

    2004-01-01

    The NASA Short-term Prediction Research and Transition (SPORT) Center seeks to accelerate the infusion of NASA Earth Science Enterprise (ESE) observations, data assimilation and modeling research into NW S forecast operations and decision-making. The Atmospheric Infrared Sounder (AIRS), is expected to advance climate research and weather prediction into the 21 st century. It is one of six instruments onboard Aqua, a satellite that is part of NASA s Earth Observing System. AIRS, along with two partner microwave sounding instruments, represents the most advanced atmospheric sounding system ever deployed in space. The system is capable of measuring the atmospheric temperature in the troposphere with radiosonde accuracies of 1 K over 1 km-thick layers under both clear and cloudy conditions, while the accuracy of the derived moisture profiles will exceed that obtained by radiosondes. It is imperative that the scientific community is prepared to take full advantage of next-generation satellite data that will become available within the next decade. The purpose of this paper is to describe a procedure designed to optimally assimilate AIRS data at high spatial resolution over both land and ocean. The assimilation system used in this study is the Local Analysis and Prediction System (LAPS) developed at the Forecast System Laboratory used extensively around the globe. Results will focus on quality control issues associated with AIRS, optimal assimilation strategies, and the impact of the AIRS data on subsequent numerical forecasts at 12 km produced by the next generation Weather Research and Forecast (WRF) model.

  20. Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange.

    PubMed

    Alden, Caroline B; Miller, John B; Gatti, Luciana V; Gloor, Manuel M; Guan, Kaiyu; Michalak, Anna M; van der Laan-Luijkx, Ingrid T; Touma, Danielle; Andrews, Arlyn; Basso, Luana S; Correia, Caio S C; Domingues, Lucas G; Joiner, Joanna; Krol, Maarten C; Lyapustin, Alexei I; Peters, Wouter; Shiga, Yoichi P; Thoning, Kirk; van der Velde, Ivar R; van Leeuwen, Thijs T; Yadav, Vineet; Diffenbaugh, Noah S

    2016-10-01

    Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (~1-8 × 10(6)  km(2) ) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub

  1. Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

    NASA Astrophysics Data System (ADS)

    Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

    2016-04-01

    Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m‑Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts

  2. Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

    NASA Astrophysics Data System (ADS)

    Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

    2016-04-01

    Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m-Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts

  3. Atmospheric mercury deposition and its contribution of the regional atmospheric transport to mercury pollution at a national forest nature reserve, southwest China.

    PubMed

    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.

  4. Influence of Atmospheric CO2 Variation on Strom Track Behavior

    NASA Astrophysics Data System (ADS)

    Martynova, Yuliya; Krupchatnikov, Vladimir

    2015-04-01

    The storm tracks are the regions of strong baroclinicity where surface cyclones occur. The effect of increase with following decrease of anthropogenic load on storm tracks activity in the Northern Hemisphere was studied. The global climate system model of intermediate complexity ('Planet Simulator', Fraedrich K. et al., 2005) was used in this study. Anthropogenic forcing was set according to climatic scenario RCP8.5 continued till 4000 AD with fixed CO2 concentration till 3000 AD and linear decrease of anthropogenic load to preindustrial value at two different rates: for 100 and 1000 years. Modeling data analysis showed meridional shift of storm tracks due to atmospheric CO2 concentration variation. When CO2 concentration increases storm tracks demonstrate poleward shifting. When CO2 concentration decreases to preindustrial value storm tracks demonstrate a tendency to equator-ward shifting. Storm tracks, however, don't recover their original activity and location to the full. This manifests itself particularly for 'fast' CO2 concentration decrease. Heat and moisture fluxes demonstrate the same behavior. In addition, analysis of eddy length scale (Kidston J. Et al., 2011) showed their increase at mid-latitudes and decrease at tropic latitudes due to intensive CO2 concentration increase. This might cause poleward shift of mid-latitude jets. Acknowledgements. This work is partially supported by SB RAS project VIII.80.2.1, RFBR grant 13-05-12034, 13-05-00480, 14-05-00502 and grant of the President of the Russian Federation. Fraedrich K., Jansen H., Kirk E., Luksch U., and Lunkeit F. The Planet Simulator: Towards a user friendly model // Meteorol. Zeitschrift. 2005, 14, 299-304. Kidston J., Vallis G.K., Dean S.M., Renwick J.A. Can the increase in the eddy length scale ander global warming cause the poleward shift of the jet streams? // J. Climate. 2011, V.24. P. 3764-3780.

  5. Effect of East Asia summer blocking on the atmospheric circulation over the region

    NASA Astrophysics Data System (ADS)

    Ahn, Joong-Bae; Park, Yong-Jun

    2015-04-01

    The influence of the boreal summer blocking on atmospheric circulation in East Asia was examined. The summer blocking occurred mostly in North Europe, Ural region, Sea of Okhotsk (OK), and northeastern Pacific. The summer blocking was the major mode in these four regions according to principal component analysis using 500 hPa geopotential heights. Among the four blocking regions, OK blocking frequencies (OK BFs) showed negative and positive correlations with summer temperature and precipitation of Northeast Asia centered around the East Sea/Sea of Japan, respectively. In particular, the OK BF had a statistically significant correlation coefficient of -0.54 with summer temperatures in the Korean Peninsula. This indicates that the summer temperature and precipitation in this region were closely related to the OK blocking. According to the composite analysis for the years of higher-than-average BF (positive BF years), the OK High became stronger and expanded, while the North Pacific High was weakened over the Korean Peninsula and Japan and an anomalously deep trough was developed in the upper layer (200 hPa). As the cool OK High expanded, the temperature decreased over Northeast Asia centered around the East Sea/Sea of Japan and the lower level (850 hPa) air converged cyclonically, resulting in the increased precipitation, which induced the divergence in the upper layer and thereby strengthened the jet stream. Thus, the boreal summer OK blocking systematically influencing the area as the most dominant mode. Acknowledgements This work was carried out with the support of Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under grant project PJ009353 and Korea Meteorological Administration Research and Development Program under grant CATER 2012-3100, Republic of Korea.

  6. Ionospheric E-region electron density and neutral atmosphere variations

    NASA Technical Reports Server (NTRS)

    Stick, T. L.

    1976-01-01

    Electron density deviations from a basic variation with the solar zenith angle were investigated. A model study was conducted in which the effects of changes in neutral and relative densities of atomic and molecular oxygen on calculated electron densities were compared with incoherent scatter measurements in the height range 100-117 km at Arecibo, Puerto Rico. The feasibility of determining tides in the neutral atmosphere from electron density profiles was studied. It was determined that variations in phase between the density and temperature variation and the comparable magnitudes of their components make it appear improbable that the useful information on tidal modes can be obtained in this way.

  7. Using Existing Arctic Atmospheric Mercury Measurements to Refine Global and Regional Scale Atmospheric Transport Models

    NASA Astrophysics Data System (ADS)

    Moore, C. W.; Dastoor, A.; Steffen, A.; Nghiem, S. V.; Agnan, Y.; Obrist, D.

    2015-12-01

    Northern hemisphere background atmospheric concentrations of gaseous elemental mercury (GEM) have been declining by up to 25% over the last ten years at some lower latitude sites. However, this decline has ranged from no decline to 9% over 10 years at Arctic long-term measurement sites. Measurements also show a highly dynamic nature of mercury (Hg) species in Arctic air and snow from early spring to the end of summer when biogeochemical transformations peak. Currently, models are unable to reproduce this variability accurately. Estimates of Hg accumulation in the Arctic and Arctic Ocean by models require a full mechanistic understanding of the multi-phase redox chemistry of Hg in air and snow as well as the role of meteorology in the physicochemical processes of Hg. We will show how findings from ground-based atmospheric Hg measurements like those made in spring 2012 during the Bromine, Ozone and Mercury Experiment (BROMEX) near Barrow, Alaska can be used to reduce the discrepancy between measurements and model output in the Canadian GEM-MACH-Hg model. The model is able to reproduce and to explain some of the variability in Arctic Hg measurements but discrepancies still remain. One improvement involves incorporation of new physical mechanisms such as the one we were able to identify during BROMEX. This mechanism, by which atmospheric mercury depletion events are abruptly ended via sea ice leads opening and inducing shallow convective mixing that replenishes GEM (and ozone) in the near surface atmospheric layer, causing an immediate recovery from the depletion event, is currently lacking in models. Future implementation of this physical mechanism will have to incorporate current remote sensing sea ice products but also rely on the development of products that can identify sea ice leads quantitatively. In this way, we can advance the knowledge of the dynamic nature of GEM in the Arctic and the impact of climate change along with new regulations on the overall

  8. Regional spatial and temporal interpolation of atmospheric PCBs: Interpretation of Lake Michigan mass balance data

    SciTech Connect

    Green, M.L.; Depinto, J.V.; Sweet, C.; Hornbuckle, K.C.

    2000-05-01

    During the Lake Michigan Mass Balance (LMMB) Project, over 600 atmospheric samples were collected at eight shoreline sites and during seven cruises. These samples were analyzed for persistent organic pollutants, including PCB congeners, atrazine, and trans-nonachlor. The authors have developed a method for interpreting the gas-phase data that includes fractionating the observed PCB concentration into land- and water-based sources. This approach accounts for differences in gas-phase atmospheric PCB concentration over water and over land. Using this fractionation approach, they have interpolated the measured data over time and space to predict PCB air concentrations over the lake during the LMMB field period. The results predict gas-phase {Sigma}PCB (sum of {approximately}98 congener groups) concentrations for each of 2,319 grid cells over the lake, on a monthly basis. The authors estimate that lake-wide monthly average {sigma}PCB gas-phase concentrations range from 0.136 to 1.158 ng/m{sup 3}, with an annual average PCB concentration of 0.457 ng/m{sup 3}. As expected, the highest concentrations of PCBs over the lake when the winds are from the southwest (out of the Chicago-Gary region) and when land surface temperatures are elevated. The predicted influence of Chicago is described on a monthly basis as a zone of elevated PCB concentrations for approximately 40 km into Lake Michigan.

  9. Atmospheric correction analysis on LANDSAT data over the Amazon region. [Manaus, Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Dias, L. A. V.; Dossantos, J. R.; Formaggio, A. R.

    1983-01-01

    The Amazon Region natural resources were studied in two ways and compared. A LANDSAT scene and its attributes were selected, and a maximum likelihood classification was made. The scene was atmospherically corrected, taking into account Amazonic peculiarities revealed by (ground truth) of the same area, and the subsequent classification. Comparison shows that the classification improves with the atmospherically corrected images.

  10. Atmospheric Rivers Induced Heavy Precipitation and Flooding in the Western U.S. Simulated by the WRF Regional Climate Model

    SciTech Connect

    Leung, Lai R.; Qian, Yun

    2009-02-12

    Twenty years of regional climate simulated by the Weather Research and Forecasting model for North America has been analyzed to study the influence of the atmospheric rivers and the role of the land surface on heavy precipitation and flooding in the western U.S. Compared to observations, the simulation realistically captured the 95th percentile extreme precipitation, mean precipitation intensity, as well as the mean precipitation and temperature anomalies of all the atmospheric river events between 1980-1999. Contrasting the 1986 President Day and 1997 New Year Day atmospheric river events, differences in atmospheric stability are found to have an influence on the spatial distribution of precipitation in the Coastal Range of northern California. Although both cases yield similar amounts of heavy precipitation, the 1997 case was found to produce more runoff compared to the 1986 case. Antecedent soil moisture, the ratio of snowfall to total precipitation (which depends on temperature), and existing snowpack all seem to play a role, leading to a higher runoff to precipitation ratio simulated for the 1997 case. This study underscores the importance of characterizing or simulating atmospheric rivers and the land surface conditions for predicting floods, and for assessing the potential impacts of climate change on heavy precipitation and flooding in the western U.S.

  11. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    NASA Astrophysics Data System (ADS)

    Schweitzer, S.; Kirchengast, G.; Proschek, V.

    2011-10-01

    LEO-LEO infrared-laser occultation (LIO) is a new occultation technique between Low Earth Orbit (LEO) satellites, which applies signals in the short wave infrared spectral range (SWIR) within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO) method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms) of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We conclude that

  12. Influence of Atmospheric Pressure and Composition on LIBS

    NASA Astrophysics Data System (ADS)

    Scott, Jill R.; Effenberger, Andrew J.; Hatch, Jeremy J.

    While laser-induced breakdown spectroscopy (LIBS) is an attractive technique because of its basic simplicity with little or no sample preparation and ability to be performed under standard Earth atmosphere, there has been increasing interest in performing LIBS under non-standard pressures and with surrounding atmospheric gases other than air. Altering the atmospheric pressure can dramatically change the observed LIBS spectra, such as greatly improving the resolution, signal intensity, and overall signal-to-noise ratio by judicious choice of pressure and gas composition. The ability to enhance LIBS spectra has enabled challenging applications related to detection of isotopes. Interest in non-standard atmospheric conditions is also driven by applications for space exploration and process monitoring as well as the opportunity to better understand the dynamics associated with the LIBS plasma.

  13. Regional forecasting with global atmospheric models; Third year report

    SciTech Connect

    Crowley, T.J.; North, G.R.; Smith, N.R.

    1994-05-01

    This report was prepared by the Applied Research Corporation (ARC), College Station, Texas, under subcontract to Pacific Northwest Laboratory (PNL) as part of a global climate studies task. The task supports site characterization work required for the selection of a potential high-level nuclear waste repository and is part of the Performance Assessment Scientific Support (PASS) Program at PNL. The work is under the overall direction of the Office of Civilian Radioactive Waste Management (OCRWM), US Department of Energy Headquarters, Washington, DC. The scope of the report is to present the results of the third year`s work on the atmospheric modeling part of the global climate studies task. The development testing of computer models and initial results are discussed. The appendices contain several studies that provide supporting information and guidance to the modeling work and further details on computer model development. Complete documentation of the models, including user information, will be prepared under separate reports and manuals.

  14. Solar activity influences on atmospheric electricity and on some structures in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Reiter, Reinhold

    1989-01-01

    Only processes in the troposphere and the lower stratosphere are reviewed. General aspects of global atmospheric electricity are summarized in Chapter 3 of NCR (1986); Volland (1984) has outlined the overall problems of atmospheric electrodynamics; and Roble and Hays (1982) published a summary of solar effects on the global circuit. The solar variability and its atmospheric effects (overview by Donelly et al, 1987) and the solar-planetary relationships (survey by James et al. 1983) are so extremely complex that only particular results and selected papers of direct relevance or historical importance are compiled herein.

  15. The influence of scales of atmospheric motion on air pollution over Portugal

    NASA Astrophysics Data System (ADS)

    Russo, Ana; Trigo, Ricardo; Mendes, Manuel; Jerez, Sonia; Gouveia, Célia Marina

    2014-05-01

    Air pollution is determined by the combination of different factors, namely, emissions, physical constrains, meteorology and chemical processes [1,2,3]. The relative importance of such factors is influenced by their interaction on diverse scales of atmospheric motion. Each scale depicts different meteorological conditions, which, when combined with the different air pollution sources and photochemistry, result in varying ambient concentrations [2]. Identifying the dominant scales of atmospheric motion over a given airshed can be of great importance for many applications such as air pollution and pollen dispersion or wind energy management [2]. Portugal has been affected by numerous air pollution episodes during the last decade. These episodes are often related to peak emissions from local industry or transport, but can also be associated to regional transport from other urban areas or to exceptional emission events, such as forest fires. This research aims to identify the scales of atmospheric motion which contribute to an increase of air pollution. A method is proposed for differentiating between the scales of atmospheric motion that can be applied on a daily basis from data collected at several wind-measuring sites in a given airshed and to reanalysis datasets. The method is based on the daily mean wind recirculation and the mean and standard deviation between sites. The determination of the thresholds between scales is performed empirically following the approach of Levy et al. [2] and also through a automatic statistical approach computed taking into account the tails of the distributions (e.g. 95% and 99% percentile) of the different wind samples. A comparison is made with two objective approaches: 1) daily synoptic classification for the same period over the region [4] and 2) a 3-D backward trajectory approach [5,6] for specific episodes. Furthermore, the outcomes are expected to support the Portuguese authorities on the implementation of strategies for a

  16. Regional scale atmospheric dispersion simulation of accidental releases of radionuclides from Fukushima Dai-ichi reactor

    NASA Astrophysics Data System (ADS)

    Srinivas, C. V.; Venkatesan, R.; Baskaran, R.; Rajagopal, V.; Venkatraman, B.

    2012-12-01

    This paper presents the results of regional scale atmospheric dispersion simulation of accidental emission of radionuclides from the Fukushima Daiichi Reactor, Japan following the Tohoku earthquake and tsunami event on 11 March 2011. The objective was to study the temporal behaviour of plume trajectory, concentration, deposition and radiation dose pattern over an 80 km range around the reactor. The time-varying meteorological parameters during the release period were simulated with a multi-scale nested atmospheric model WRF ARW and the trajectory, plume dispersion were computed with Lagrangian Particle Dispersion models HYSPLIT, FLEXPART using the available information on accidental source term. The simulations indicated that the wind flow over Japan during the release period was driven by the large scale extra-tropical westerly waves and associated low pressure systems. In the lower levels, the flow was influenced by the local topography/sea breeze causing occasional landward wind shift on the east coast of Japan. Simulated airflow trajectories revealed that the plume stayed over the ocean by westerly winds on most days and the radioactivity dispersed over sea surface. Landward trajectories were found on a few days due to southeasterly, easterly and northeasterly flow (15-17, 19-21 March 2011) during which much of the radionuclides deposited over the land region. The hotspot of depositions occurred over east Pacific Ocean near to Japan. Over the land relatively high depositions were simulated in a narrow zone of 20 km width and 80 km length in the northwest sector in agreement with monitor data. Simulations showed wet depositions over the land to be higher than the dry depositions during 12-30 March due to occurrence of rainfall on some days. Comparison of activity deposition and air dose values with available observations confirmed that the plume pattern in a finer length scale around the site could be simulated realistically and agree with the measurements

  17. Coordinated radar observations of atmospheric diurnal tides in equatorial regions

    NASA Astrophysics Data System (ADS)

    Tsuda, Toshitaka; Ohnishi, Kazunori; Isoda, Fusako; Nakamura, Takuji; Vincent, Robert A.; Reid, Iain M.; Harijono, Sri Woro B.; Sribimawati, Tien; Nuryanto, Agus; Wiryosumarto, Harsono

    1999-07-01

    The long-term behavior of atmospheric tides in the mesosphere and lower thermosphere has been observed with the meteor wind radar (MWR) in Jakarta, Indonesia (6°S, 107°E) from November 1992 to August 1997. The amplitudes and phases of the diurnal tides show systematic seasonal variations, particularly distinct in the meridional component. In addition, substantial interannual variability is evident, characterized by a biennial periodicity of tidal parameters, and considerably small tidal amplitudes exclusively seen in 1996. The MWR results are compared with the Global Scale Wave Model (GSWM) as well as MF radar data collected in two equatorial sites in Pontianak (0.03°N, 109°E) and Christmas Island (2°N, 158°W) for November 1995-July 1997 and January 1996-October 1997, respectively. Comparison studies of these radar data have revealed the detailed latitudinal structure of the diurnal tide near the equator. The GSWM has successfully described the general characteristics of the radar results, although some discrepancies are recognized. In 1996 when radar data are available at all the three sites, the monthly mean values of tidal amplitudes at 90 km agreed very well between Jakarta and Pontianak, while significant discrepancy was found for Christmas Island, suggesting the existence of geographical effects such as non-migrating tides.

  18. Disentangling natural and anthropogenic sources of atmospheric sulfur in an industrial region using biomonitors.

    PubMed

    Barros, Ceres; Pinho, Pedro; Durão, Rita; Augusto, Sofia; Máguas, Cristina; Pereira, Maria João; Branquinho, Cristina

    2015-02-17

    Despite reductions in atmospheric sulfur (S) concentrations due to abatement policies in some countries, modeling the dispersion of this pollutant and disentangling anthropogenic sources from natural ones is still of great concern. Lichens have been used as biomonitors of the impacts of S for over 40 years, but their potential as source-tracers of specific sources, including natural ones, remains unexplored. In fact, few attempts have been made to try to distinguish and spatially model different sources of S using lichens. We have measured S concentrations and isotopic values in lichens within an industrial coastal region where different sources of S, natural and anthropogenic, interplay. We detected a prevailing influence of natural sea-originated S that mixed with anthropogenic sources of S. We were then able to disentangle the sources of S, by removing the ocean influence on S isotopic values, enabling us to model the impact of different anthropogenic sources on S deposition and highlighting the potential use of lichens to evaluate the weight of different types of anthropogenic sources.

  19. The influence absorb stratification on absorptivity of atmosphere

    NASA Astrophysics Data System (ADS)

    Goryachev, B. V.; Mogilnitskiy, S. B.

    2014-11-01

    The authors have studied the radiation transfer in multilayer atmosphere. The analytical formulae for the calculation of the transmission coefficient, reflectance and absorption of dispersion media consisting of three plane layers were obtained. It was shown that absorption of dispersed media depends strongly on absorption layer's position in dispersed media. The lowest value is marked when the layer takes place below of the media the light falls from above. Investigation of the radiation balance of the atmosphere is usually conducted on the basis of the theory of radiative transfer and numerical methods [1]. In conducting research using various models of the atmosphere [2-4]. Accuracy of the results depends on the accuracy of the approximation and taking into account all the effects that significantly affect the results, such as the effect of the spatial limitations of the dispersion medium [4-6].

  20. The Influence of Solar Proton Events in Solar Cycle 23 on the Neutral Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; vonKonig, Miriam; Anderson, John; Roble, Raymond G.; McPeters, Richard D.; Fleming, Eric L.; Russell, James M.

    2004-01-01

    Solar proton events (SPEs) can cause changes in constituents in the Earth's middle atmosphere. The highly energetic protons cause ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which lead to the production of HO(x) (H, OH, HO2) and NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The HO(x) increases lead to short-lived ozone decreases in the mesosphere and upper stratosphere due to the short lifetimes of the HO, constituents. The NO(x) increases lead to long-lived stratospheric ozone changes because of the long lifetime of NO(y) constituents in this region. Solar cycle 23 was quite active with SPEs and very large fluxes of high energy protons occurred in July and November 2000, November 200 1, and April 2002. Smaller, but still substantial, proton fluxes impacted the Earth during other months in the 1997-2003 time period. The impact of the very large SPEs on the neutral middle atmosphere during solar cycle 23 will be discussed, including the HO(x), NO(y), ozone variations and induced atmospheric transport changes. Two multi-dimensional models, the Goddard Space Flight Center (GSFC) Two-dimensional (2D) Model and the Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM), were used in computing the influence of the SPEs. The results of the GSFC 2D Model and the TIME-GCM will be shown along with comparisons to the Upper Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) and Solar Backscatter Ultraviolet 2 (SBUV/2) instruments.

  1. Potential for atmospheric deposition of bacteria to influence bacterioplankton communities.

    PubMed

    Jones, Stuart E; Newton, Ryan J; McMahon, Katherine D

    2008-06-01

    Biogeographic patterns in microbial communities are an exciting but controversial topic in microbial ecology. Advances in theory pertaining to assembly of microbial communities have made strong assumptions about dispersal of bacteria without exploration. For this reason, we investigated rates of atmospheric bacterial deposition and compared the taxonomic composition of bacteria in rain with that of common freshwater bacterial communities. Our findings suggest that it is not appropriate to take for granted that atmospheric deposition of bacteria is a significant vector of immigration to freshwater ecosystems.

  2. The significance of the episodic nature of atmospheric deposition to Low Nutrient Low Chlorophyll regions

    NASA Astrophysics Data System (ADS)

    Guieu, C.; Aumont, O.; Paytan, A.; Bopp, L.; Law, C. S.; Mahowald, N.; Achterberg, E. P.; Marañón, E.; Salihoglu, B.; Crise, A.; Wagener, T.; Herut, B.; Desboeufs, K.; Kanakidou, M.; Olgun, N.; Peters, F.; Pulido-Villena, E.; Tovar-Sanchez, A.; Völker, C.

    2014-11-01

    In the vast Low Nutrient Low-Chlorophyll (LNLC) Ocean, the vertical nutrient supply from the subsurface to the sunlit surface waters is low, and atmospheric contribution of nutrients may be one order of magnitude greater over short timescales. The short turnover time of atmospheric Fe and N supply (<1 month for nitrate) further supports deposition being an important source of nutrients in LNLC regions. Yet, the extent to which atmospheric inputs are impacting biological activity and modifying the carbon balance in oligotrophic environments has not been constrained. Here, we quantify and compare the biogeochemical impacts of atmospheric deposition in LNLC regions using both a compilation of experimental data and model outputs. A metadata-analysis of recently conducted field and laboratory bioassay experiments reveals complex responses, and the overall impact is not a simple "fertilization effect of increasing phytoplankton biomass" as observed in HNLC regions. Although phytoplankton growth may be enhanced, increases in bacterial activity and respiration result in weakening of biological carbon sequestration. The application of models using climatological or time-averaged non-synoptic deposition rates produced responses that were generally much lower than observed in the bioassay experiments. We demonstrate that experimental data and model outputs show better agreement on short timescale (days to weeks) when strong synoptic pulse of aerosols deposition, similar in magnitude to those observed in the field and introduced in bioassay experiments, is superimposed over the mean atmospheric deposition fields. These results suggest that atmospheric impacts in LNLC regions have been underestimated by models, at least at daily to weekly timescales, as they typically overlook large synoptic variations in atmospheric deposition and associated nutrient and particle inputs. Inclusion of the large synoptic variability of atmospheric input, and improved representation and

  3. Longitudinal variations in the Saturnian atmosphere. I - Equatorial region

    NASA Astrophysics Data System (ADS)

    Killen, R. M.

    1988-02-01

    Longitudinal variations in the equatorial regions of Saturn are sought in both Voyager orange and methane-filter and ground-based 6000-6600 A observations. The spectral variations found are inconsistent with reflecting layer height variation; they are alternatively modeled by changes in the single-scattering albedo of the haze, as well as in the specific abundance of haze gas. The 500-km spatial resolution data furnished by Voyager are found to be consistent with a specific abundance of haze gas between 10 and 24 km-am. Ammonia and methane mixing ratios are derived.

  4. Aerosol variability and atmospheric transport in the Himalayan region from CALIOP 2007-2010 observations

    NASA Astrophysics Data System (ADS)

    Bucci, S.; Cagnazzo, C.; Cairo, F.; Di Liberto, L.; Fierli, F.

    2013-06-01

    Himalayan Plateau is surrounded by regions with high natural and anthropogenic aerosol emissions that have a strong impact on regional climate. This is particularly critical for the Himalayan glaciers whose equilibrium is also largely influenced by radiative direct and indirect effects induced by aerosol burden. This work focuses on the spatial and vertical distribution of different aerosol types, their seasonal variability and sources. The analysis of the 2007-2010 yr of CALIPSO vertically resolved satellite data allows the identification of spatial patterns of desert dust and carbonaceous particles in different atmospheric layers. Clusters of Lagrangian back-trajectories highlight the transport pathways from source regions during the dusty spring season. The analysis shows a prevalence of dust; at low heights they are distributed mainly north (with a main contribution from the Gobi and Taklamakan deserts) and west of the Tibetan Plateau (originating from the deserts of South-West Asia and advected by the westerlies). Above the Himalayas the dust amount is minor but still not negligible (detectable in around 20% of the measurements), and transport from more distant deserts (Sahara and Arabian Peninsula) is important. Smoke aerosol, produced mainly in North India and East China, is subject to shorter range transport and is indeed observed closer to the sources while there is a limited amount reaching the top of the plateau. Data analysis reveals a clear seasonal variability in the frequencies of occurrence for the main aerosol types; dust is regulated principally by the monsoon dynamics, with maxima of occurrence in spring. The study also highlights relevant interannual differences, showing a larger presence of aerosol in the region during 2007 and 2008 yr.

  5. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    NASA Astrophysics Data System (ADS)

    Schweitzer, S.; Kirchengast, G.; Proschek, V.

    2011-05-01

    be as well made negligible by a design with a close time spacing (within 5 ms) of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by a design allowing retrieval of a cloud layering profile from reference signals and its use in trace species retrieval when scanning through intermittent upper tropospheric cloudiness. Wind can have a small influence via Doppler shift resulting in a slightly modified trace species absorption in comparison to calm air, which can be made negligible by using a simultaneously retrieved wind speed profile or a moderately accurate (to about 10 m s-1) background wind profile. Considering all these influences, we conclude that the set of SWIR channels proposed for implementing the LMIO method (Kirchengast et al., 2010; Kirchengast and Schweitzer, 2011) provides adequate sensitivity to accurately retrieve eight greenhouse gas/isotope trace species of key importance to climate and atmospheric chemistry (H2O, 12CO2, 13CO2, C18OO, CH4, N2O, O3, CO) in the upper troposphere/lower stratosphere region outside clouds under all atmospheric conditions. Two further isotope species (HDO, H218O) can be retrieved in the upper troposphere.

  6. The Influence of Humorous Atmosphere on Divergent Thinking.

    ERIC Educational Resources Information Center

    Ziv, Avner

    1983-01-01

    In one experiment, 78 adolescents were shown humorous film clips and required to write captions for cartoons. A creativity test was administered. In a second study, the experimental group completed the Torrance Creativity Test with humorous responses. In both studies, a humorous atmosphere was found to significantly increase creativity scores.…

  7. Influence of atmospheric structure and topography on infrasonic wave propagation

    NASA Astrophysics Data System (ADS)

    Lacanna, G.; Ichihara, M.; Iwakuni, M.; Takeo, M.; Iguchi, M.; Ripepe, M.

    2014-04-01

    The effects of topography and atmospheric structures on infrasonic wave propagation from a volcanic source were investigated using observations and numerical modeling. This paper presents the first long-term observational data set showing spatiotemporal variations in patterns of infrasound propagation at distances of up to 60 km from a persistently active infrasound source (Sakurajima Volcano, Japan). The data show that the amplitudes of infrasonic waves received at distant stations relative to those received at a reference station close to the source can vary up to an order of magnitude over short time intervals and short distances and that they do not follow the theoretical geometric decay expected for homogeneous media. Moreover, waveforms also change significantly in both time and space. Numerical simulations were performed using a two-dimensional finite difference time domain (2-D FDTD) method. Effects of atmospheric structure and topography are included in a vertical section parallel to the wave propagation direction. The simulation successfully reproduced the variations of amplitudes and waveforms. Results are interpreted in terms of wave refraction due to sound and wind speed gradients and wave diffraction at topographic barriers. Our numerical results indicate that both atmospheric and topographic propagation effects are nonnegligible. To evaluate the propagation effects and determine source processes in spatially and temporally varying infrasound data, atmospheric data with a time resolution higher than is currently available are required. If the data are available, the present results suggest that the propagation effects could be evaluated using 2-D FDTD modeling at realistic calculation times.

  8. An objective prior error quantification for regional atmospheric inverse applications

    NASA Astrophysics Data System (ADS)

    Kountouris, P.; Gerbig, C.; Totsche, K.-U.; Dolman, A. J.; Meesters, A. G. C. A.; Broquet, G.; Maignan, F.; Gioli, B.; Montagnani, L.; Helfter, C.

    2015-12-01

    Assigning proper prior uncertainties for inverse modelling of CO2 is of high importance, both to regularise the otherwise ill-constrained inverse problem and to quantitatively characterise the magnitude and structure of the error between prior and "true" flux. We use surface fluxes derived from three biosphere models - VPRM, ORCHIDEE, and 5PM - and compare them against daily averaged fluxes from 53 eddy covariance sites across Europe for the year 2007 and against repeated aircraft flux measurements encompassing spatial transects. In addition we create synthetic observations using modelled fluxes instead of the observed ones to explore the potential to infer prior uncertainties from model-model residuals. To ensure the realism of the synthetic data analysis, a random measurement noise was added to the modelled tower fluxes which were used as reference. The temporal autocorrelation time for tower model-data residuals was found to be around 30 days for both VPRM and ORCHIDEE but significantly different for the 5PM model with 70 days. This difference is caused by a few sites with large biases between the data and the 5PM model. The spatial correlation of the model-data residuals for all models was found to be very short, up to few tens of kilometres but with uncertainties up to 100 % of this estimation. Propagating this error structure to annual continental scale yields an uncertainty of 0.06 Gt C and strongly underestimates uncertainties typically used from atmospheric inversion systems, revealing another potential source of errors. Long spatial e-folding correlation lengths up to several hundreds of kilometres were determined when synthetic data were used. Results from repeated aircraft transects in south-western France are consistent with those obtained from the tower sites in terms of spatial autocorrelation (35 km on average) while temporal autocorrelation is markedly lower (13 days). Our findings suggest that the different prior models have a common temporal

  9. [Characteristics of Winter Atmospheric Mixing Layer Height in Beijing-Tianjin-Hebei Region and Their Relationship with the Atmospheric Pollution].

    PubMed

    Li, Meng; Tang, Gui-qian; Huang, Jun; Liu, Zi-rui; An, Jun-lin; Wang, Yue-si

    2015-06-01

    Atmospheric mixing layer height (MLH) is one of the main factors affecting the atmospheric diffusion and plays an important role in air quality assessment and distribution of the pollutants. Based on the ceilometers data, this paper has made synchronous observation on MLH in Beijing-Tianjin-Hebei region (Beijing, Tianjin, Shijiazhuang and Qinhuangdao) in heavy polluted February 2014 and analyzed the respective overall change and its regional features. Results show that in February 2014,the average of mixing layer height in Qinhuangdao is the highest, up to 865 +/- 268 m, and in Shijiazhuang is the lowest (568 +/- 207 m), Beijing's and Tianjin's are in between, 818 +/- 319 m and 834 +/- 334 m respectively; Combined with the meteorological data, we find that radiation and wind speed are main factors of the mixing layer height; The relationship between the particle concentration and mixing layer height in four sites suggests that mixing layer is less than 800 m, concentration of fine particulate matter in four sites will exceed the national standard (GB 3095-2012, 75 microg x m(-3)). During the period of observation, the proportion of days that mixing layer is less than 800 m in Beijing, Tianjin, Shijiazhuang and Qinhuangdao are 50%, 43%, 80% and 50% respectively. Shijiazhuang though nearly formation contaminant concentration is high, within the atmospheric mixed layer pollutant load is not high. Unfavorable atmospheric diffusion conditions are the main causes of heavy pollution in Shijiazhuang for a long time. The results of the study are of great significance for cognitive Beijing-Tianjin-Hebei area pollution distribution, and can provide a scientific reference for reasonable distribution of regional pollution sources.

  10. Regional model studies of the atmospheric dispersion of fine volcanic ash after the eruption of Eyjafjallajoekull

    NASA Astrophysics Data System (ADS)

    Langmann, B.; Hort, M. K.

    2010-12-01

    During the eruption of Eyjafjallajoekull on Iceland in April/May 2010 air traffic over Europe was repeatedly interrupted because of volcanic ash in the atmosphere. This completely unusual situation in Europe leads to the demand of improved crisis management, e.g. European wide regulations of volcanic ash thresholds and improved forecasts of theses thresholds. However, the quality of the forecast of fine volcanic ash concentrations in the atmosphere depends to a great extent on a realistic description of the erupted mass flux of fine ash particles, which is rather uncertain. Numerous aerosol measurements (ground based and satellite remote sensing, and in situ measurements) all over Europe have tracked the volcanic ash clouds during the eruption of Eyjafjallajoekull offering the possibility for an interdisciplinary effort between volcanologists and aerosol researchers to analyse the release and dispersion of fine volcanic ash in order to better understand the needs for realistic volcanic ash forecasts. This contribution describes the uncertainties related to the amount of fine volcanic ash released from Eyjafjallajoekull and its influence on the dispersion of volcanic ash over Europe by numerical modeling. We use the three-dimensional Eulerian atmosphere-chemistry/aerosol model REMOTE (Langmann et al., 2008) to simulate the distribution of volcanic ash as well as its deposition after the eruptions of Eyjafjallajoekull during April and May 2010. The model has been used before to simulate the fate of the volcanic ash after the volcanic eruptions of Kasatochi in 2008 (Langmann et al., 2010) and Mt. Pinatubo in 1991. Comparing our model results with available measurements for the Eyjafjallajoekull eruption we find a quite good agreement with available ash concentrations data measured over Europe as well as with the results from other models. Langmann, B., K. Zakšek and M. Hort, Atmospheric distribution and removal of volcanic ash after the eruption of Kasatochi volcano

  11. Deuterium excess in the atmospheric water vapour of a Mediterranean coastal wetland: regional vs. local signatures

    NASA Astrophysics Data System (ADS)

    Delattre, H.; Vallet-Coulomb, C.; Sonzogni, C.

    2015-09-01

    Stable isotopes of water vapour represent a powerful tool for tracing atmospheric vapour origin and mixing processes. Laser spectrometry recently allowed high time-resolution measurements, but despite an increasing number of experimental studies, there is still a need for a better understanding of the isotopic signal variability at different time scales. We present results of in situ measurements of δ18O and δD during 36 consecutive days in summer 2011 in atmospheric vapour of a Mediterranean coastal wetland exposed to high evaporation (Camargue, Rhône River delta, France). The mean composition of atmospheric vapour (δv) is δ18O = -14.66 ‰ and δD = - 95.4 ‰, with data plotting clearly above the local meteoric water line on a δ18O-δD plot, and an average deuterium excess (d) of 21.9 ‰. Important diurnal d variations are observed, and an hourly time scale analysis is necessary to interpret the main processes involved in its variability. After having classified the data according to air mass back trajectories, we analyse the average daily cycles relating to the two main meteorological situations, i.e. air masses originating from North Atlantic Ocean and Mediterranean Sea. In both situations, we show that diurnal fluctuations are driven by (1) the influence of local evaporation, culminating during daytime, and leading to an increase in absolute water vapour concentration associated to a δv enrichment and d increase; (2) vertical air mass redistribution when the Planetary Boundary Layer collapses in the evening, leading to a d decrease, and (3) dew formation during the night, producing a δv depletion with d remaining stable. Using a two-component mixing model, we calculate the average composition of the locally evaporated vapour (δE). We find higher d(E) under North Atlantic air mass conditions, which is consistent with lower humidity conditions. We also suggest that δv measured when the PBL collapses is the most representative of a regional signal

  12. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign.

    PubMed

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B; Jaffe, Daniel A; Kleinman, Lawrence; Sedlacek, Arthur J; Briggs, Nicole L; Hee, Jonathan; Fortner, Edward; Shilling, John E; Worsnop, Douglas; Yokelson, Robert J; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K; Pekour, Mikhail S; Springston, Stephen; Zhang, Qi

    2016-08-16

    Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (∼2700 m a.s.l.) as well as near their sources using an aircraft. The regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), an index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (∼1 h old) and emissions sampled after atmospheric transport (6-45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.

  13. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign.

    PubMed

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B; Jaffe, Daniel A; Kleinman, Lawrence; Sedlacek, Arthur J; Briggs, Nicole L; Hee, Jonathan; Fortner, Edward; Shilling, John E; Worsnop, Douglas; Yokelson, Robert J; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K; Pekour, Mikhail S; Springston, Stephen; Zhang, Qi

    2016-08-16

    Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (∼2700 m a.s.l.) as well as near their sources using an aircraft. The regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), an index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (∼1 h old) and emissions sampled after atmospheric transport (6-45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate. PMID:27398804

  14. Influence of Atmospheric Pressure Torch Plasma Irradiation on Plant Growth

    NASA Astrophysics Data System (ADS)

    Akiyoshi, Yusuke; Hayashi, Nobuya; Kitazaki, Satoshi; Koga, Kazunori; Shiratani, Masaharu

    2011-10-01

    Growth stimulation characteristics of plants seeds are investigated by an atmospheric discharge irradiation into plasma seeds. Atmospheric pressure plasma torch is consisted of alumina ceramics tube and the steel mesh electrodes wind inside and outside of the tube. When AC high voltage (8 kHz) is applied to the electrode gap, the barrier discharge plasma is produced inside the alumina ceramics tube. The barrier discharge plasma is blown outside with the gas flow in ceramics tube. Radish sprouts seeds locate at 1 cm from the torch edge. The growth stimulation was observed in the length of a stem and a root after the plasma irradiation. The stem length increases approximately 2.8 times at the cultivation time of 24 h. And the growth stimulation effect is found to be maintained for 40 h, after sowing seeds. The mechanism of the growth stimulation would be the redox reaction inside plant cells induced by oxygen radicals.

  15. Volcanoes and atmospheres; catastrophic influences on the planets

    USGS Publications Warehouse

    Kieffer, S.W.

    1986-01-01

    For a rare and brief instant in geologic time, we can imagine that the sulfurous, chromatic surface of Io (one of the satellites of Jupiter) lies quiet. Perhaps stars glisten brilliantly through the tenuous nigh sky. Here and there, thick icy fogs enshroud fumaroles where sulfur dioxide leaks from the underworld. Suddenly, a fissure splits the surface and billowing clouds of sulfurous gases and ice hurl orange and black ash into the atmosphere. Minute by minute, the intensity of the eruption builds; stars begin disappearing from the night sky. The rising plume inhales the nearby atmosphere, mixing it with the exhalations from the volcano. Particles of sulfur, sulfur dioxide snow and ash rise to 300 kilometers, later raining down across the planet a thousand kilometers away. 

  16. Influence of atmospheric factors on the rheumatic diseases.

    PubMed

    Latman, N S

    1987-01-15

    There appears to be ample evidence to conclude that various meteorological factors do exert a significant impact on some people with various rheumatic diseases. The data is, however, crude relative to our general understanding. Most of this research on RA has dealt with the primary signs and symptoms of inflammation. We know, however, many of the chemical mediators of inflammation. It seems like a logical progression of research to determine the effects of the meteorological/atmospheric factors of concern on these specific intrinsic mediators of inflammation. In general, gout can be very well controlled through medication. The evidence suggests, however, that we may gain a much better understanding of how atmospheric factors such as temperature can effect the body through changes in its physico-chemical processes by using Gout as a model. The work with SLE has already yielded useful applications. Sun screening pharmaceuticals have been quite successful in reducing exacerbations of symptoms. But we don't know why only some people are photosensitive. The previous research on the effects of atmospheric factors on the rheumatic diseases has illustrated key issues in methodology: large sample sizes are critical, objective and quantifiable disease variables are important, the variables measured must be specific to the questions investigated, the diseases investigated must be as specifically and accurately defined as possible, and the various aspects of 'weather' to be investigated must be specifically defined and quantified. It is apparent that there is much more important and useful work to be performed before we can understand the effects of atmospheric factors on the rheumatic diseases.

  17. Influence of atmospheric phase compensation on optical heterodyne power measurements.

    PubMed

    Belmonte, Aniceto

    2008-04-28

    The simulation of beam propagation is used to examine the uncertainty inherent to the process of optical power measurement with a practical heterodyne receiver because of the presence of refractive turbulence. Phase-compensated heterodyne receivers offer the potential for overcoming the limitations imposed by the atmosphere by the partial correction of turbulence-induced wave-front phase aberrations. However, wave-front amplitude fluctuations can limit the compensation process and diminish the achievable heterodyne performance.

  18. The influence of atmospheric pressure on landfill methane emissions.

    PubMed

    Czepiel, P M; Shorter, J H; Mosher, B; Allwine, E; McManus, J B; Harriss, R C; Kolb, C E; Lamb, B K

    2003-01-01

    Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  19. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    SciTech Connect

    Penner, J.E.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  20. Studies of regional-scale climate variability and change. Hidden Markov models and coupled ocean-atmosphere modes

    SciTech Connect

    Ghil, M.; Kravtsov, S.; Robertson, A. W.; Smyth, P.

    2008-10-14

    This project was a continuation of previous work under DOE CCPP funding, in which we had developed a twin approach of probabilistic network (PN) models (sometimes called dynamic Bayesian networks) and intermediate-complexity coupled ocean-atmosphere models (ICMs) to identify the predictable modes of climate variability and to investigate their impacts on the regional scale. We had developed a family of PNs (similar to Hidden Markov Models) to simulate historical records of daily rainfall, and used them to downscale GCM seasonal predictions. Using an idealized atmospheric model, we had established a novel mechanism through which ocean-induced sea-surface temperature (SST) anomalies might influence large-scale atmospheric circulation patterns on interannual and longer time scales; we had found similar patterns in a hybrid coupled ocean-atmosphere-sea-ice model. The goal of the this continuation project was to build on these ICM results and PN model development to address prediction of rainfall and temperature statistics at the local scale, associated with global climate variability and change, and to investigate the impact of the latter on coupled ocean-atmosphere modes. Our main results from the grant consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling together with the development of associated software; new intermediate coupled models; a new methodology of inverse modeling for linking ICMs with observations and GCM results; and, observational studies of decadal and multi-decadal natural climate results, informed by ICM results.

  1. Atmospheric sensitivity to roughness length in a regional atmospheric model over the Ohio-Tennessee River Valley

    NASA Astrophysics Data System (ADS)

    Quintanar, Arturo I.; Mahmood, Rezaul; Suarez, Astrid; Leeper, Ronnie

    2016-06-01

    The response of a regional atmospheric model to small changes in roughness length of two vegetation categories (crops and deciduous broadleaf forest) was analyzed for three synoptic events in June 2006. These were characterized by two convective events (June 11 and 22) and one prefrontal event (June 17). The responses of the model, for precipitation, equivalent potential temperature and wind field were notable in general. However, the response became muted as roughness lengths were increased or decreased. Atmospheric response to these changes varied for different convective events. A small dependence on roughness length was found for the sensible and latent heat fluxes and planetary boundary layer heights during the convective event of June 11. For the June 22 event, the model response was weaker for the crop-only and forest-only roughness length experiments compared to the response when both the crop and forest-only roughness length were changed in combination.

  2. Influence of the solar atmosphere on the p-mode eigenoscillations

    NASA Astrophysics Data System (ADS)

    Dzhalilov, N. S.; Staude, J.; Arlt, K.

    2000-09-01

    An asymptotic theory of global adiabatic p-modes is developed, taking into account the influence of the solar atmosphere. It is shown that waves of the whole frequency range nu ~ 2-10 mHz may reach the chromosphere-corona transition region (CCTR) by means of a tunneling through the atmospheric barriers. The primary acoustic cavity inside the Sun becomes considerably extended by this way, leading to a change of frequencies: low frequencies are increased, while high frequencies are decreased. The transition from low p-mode frequencies to high peak frequencies (nu >~ 6;mHz) is smooth. The locations of the turning points are determined from the wave equation for {div}*/rightarrow{v}. It is shown that the internal turning point of the acoustic cavity is strongly shifted toward the center of the Sun, while the upper turning point is shifted from the surface to CCTR. That means, the turning points cannot be located in the convective zone. A new complex integral dispersion relation for the eigenfrequencies is derived. The imaginary parts of the frequencies indicate a decay of the amplitudes, resulting from considerable energy losses by tunneling from the main cavity. It is shown that waves with a decaying amplitude (complex frequency) may exist in a limited area only, penetration of linear p-modes to the corona is impossible. The CCTR acts as a free surface. We conclude that the p-modes may drive forced surface gravity waves at this surface.

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

    SciTech Connect

    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.

  4. The influence of atmospheric pressure on landfill methane emissions

    SciTech Connect

    Czepiel, P.M.; Shorter, J.H.; Mosher, B.; Allwine, E.; McManus, J.B.; Harriss, R.C.; Kolb, C.E.; Lamb, B.K

    2003-07-01

    Landfills are the largest source of anthropogenic methane (CH{sub 4}) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH{sub 4} emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH{sub 4} emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m{sup 3} CH{sub 4} min{sup -1}. A simple regression model of our results was used to calculate an annual emission rate of 8.4x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These data, along with CH{sub 4} oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH{sub 4} generation at this landfill. A reported gas collection rate of 7.1x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} and an estimated annual rate of CH{sub 4} oxidation by cover soils of 1.2x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} resulted in a calculated annual CH{sub 4} generation rate of 16.7x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  5. The effect of regional ocean-atmosphere coupling on the long-term variability in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Feng, Lin; Wu, Dexing; Lin, Xiaopei; Meng, Xiangfeng

    2010-03-01

    A fully coupled ocean-atmosphere model is applied to highlight the mechanism of the long-term variability (including decadal and longer time scales) in the Pacific Ocean. We are interested in the effect of oceanatmosphere coupling of different regions during these processes. The control run successfully simulates the Pacific long-term variability, whose leading modes are the Pacific (inter) Decadal Oscillation (PDO) and the North Pacific mode (NPM). Furthermore, three numerical experiments are conducted, shutting down the ocean-atmosphere coupling in the North Pacific, the tropical Pacific, and the South Pacific, respectively. The results show that regional ocean-atmosphere coupling is not only important to the strength of local long-term SST variability but also has an influence on the variability further afield. In both the tropical Pacific and North Pacific, this local effect is the main control, which is much more obvious in the tropical regions. The existence of the PDO is extremely dependent on the coupling in the tropical Pacific. However, extratropical coupling, in particular that in the North Pacific, is also important to form its spatial pattern and strengthen the variability in some tropical areas. For the NPM, its existence is primarily determined by the coupling in the North Pacific.

  6. External interannual ENSO forcing : which regions outside equatorial Pacific may influence the evolution of ENSO ?

    NASA Astrophysics Data System (ADS)

    Dayan, H.; Vialard, J.; Izumo, T.; Lengaigne, M.; Terray, P.

    2012-04-01

    Low-frequency coupled ocean-atmosphere dynamics intrinsic to the Pacific Ocean are essential to El Niño development. Some recent studies (e.g Annamalai 2005, Izumo and al. 2010, Rodriguez-Fonseca 2009, Terray 2010, Vimont and al. 2003) however suggest that external interannual forcing may influence the evolution of El Niño. In the present study, we aim at identifying regions outside the Pacific Ocean, which can affect the evolution of ENSO. Our assumption is that zonal wind anomalies within the Pacific equatorial waveguide are a necessary condition to influence ENSO evolution. We thus aim at identifying teleconnections between SST anomalies outside of the equatorial Pacific, and Pacific equatorial zonal wind anomalies that are independent of ENSO. To that end, we first remove the ENSO signal from interannual wind and SST anomalies in several re-analyses by regression to all the principal components of an EOF analysis of Tropical Pacific Sea Surface Temperature which display significant correlations with Niño3.4 within 12 months of the ENSO peak. Results show that non-negligible (25% of interannual variance) ENSO-independent zonal winds anomalies remain in the western/central equatorial Pacific. We further show that SST anomalies in six regions (equatorial, northern and southern central Pacific; Tropical and southern Atlantic and southern Indian Ocean) display significant 0-3 months lead correlations to those ENSO-independent wind variations. These regions may hence influence ENSO evolution through remote influence on equatorial Pacific winds, as previously suggested by, e.g, Rodriguez-Fonseca (2009), Terray (2010), Vimont and al. (2003). While our statistical methodology did allow to isolate those regions, we still have to confirm from forced atmospheric and coupled simulations that: - SST anomalies in those regions can indeed influence zonal winds over the tropical Pacific, - the response of the Tropical Pacific coupled system to this external forcing can lead

  7. The Influence of High Aerosol Concentration on Atmospheric Boundary Layer Temperature Stratification

    SciTech Connect

    Khaykin, M.N.; Kadygrove, E.N.; Golitsyn, G.S.

    2005-03-18

    Investigations of the changing in the atmospheric boundary layer (ABL) radiation balance as cased by natural and anthropogenic reasons is an important topic of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program. The influence of aerosol on temperature stratification of ABL while its concentration was extremely high within a long period of time was studied experimentally. The case was observed in Moscow region (Russia) with the transport of combustion products from peat-bog and forest fires in July-September, 2002. At this time the visibility was some times at about 100-300 m. Aerosol concentration measured by Moscow University Observatory and A.M. Obukhov Institute of Atmospheric Physics field station in Zvenigorod (55.7 N; 36.6 E) for several days was in 50-100 times more than background one (Gorchakov at al 2003). The high aerosol concentration can change the radiation balance at ABL, and so to change thermal stratification in ABL above the mega lopolis. For the analysis the data were used of synchronous measurements by MTP-5 (Microwave Temperature Profiler operating at wavelength 5 mm) in two locations, namely: downtown Moscow and country-side which is 50 km apart to the West (Zvenigorod station). (Kadygrov and Pick 1998; Westwater at al 1999; Kadygrov at al 2002). Zvenigorod station is located in strongly continental climate zone which is in between of the climates of ARM sites (NSANorth Slope of Alaska and SGP-Southern Great Plains). The town of Zvenigorod has little industry, small traffic volume and topography conductive to a good air ventilation of the town. For these reasons Zvenigorod can be considered as an undisturbed rural site. For the analysis some days were chosen with close meteorological parameters (average temperature, humidity, wind, pressure and cloud form) but strongly differing in aerosol concentration level.

  8. Proximate humid and dry regions in Jupiter's atmosphere indicate complex local meteorology.

    PubMed

    Roos-Serote, M; Vasavada, A R; Kamp, L; Drossart, P; Irwin, P; Nixon, C; Carlson, R W

    2000-05-11

    Models of Jupiter's formation and structure predict that its atmosphere is enriched in oxygen, relative to the Sun, and that consequently water clouds should be present globally near the 5-bar pressure level. Past attempts to confirm these predictions have led to contradictory results; in particular, the Galileo probe revealed a very dry atmosphere at the entry site, with no significant clouds at depths exceeding the 2-bar level. Although the entry site was known to be relatively cloud-free, the contrast between the observed local dryness and the expected global wetness was surprising. Here we analyse near-infrared (around 5 microm) observations of Jupiter, a spectral region that can reveal the water vapour abundance and vertical cloud structure in the troposphere. We find that humid and extremely dry regions exist in close proximity, and that some humid regions are spatially correlated with bright convective clouds extending from the deep water clouds to the visible atmosphere.

  9. Influence of modified atmosphere packaging on 'Star Ruby' grapefruit phytochemicals.

    PubMed

    Chaudhary, Priyanka R; Jayaprakasha, G K; Porat, Ron; Patil, Bhimanagouda S

    2015-01-28

    Modified atmosphere packaging (MAP) can extend the shelf life of salads, vegetables, and fruits by generating a storage environment with low O2, high CO2, and high humidity. The current study investigates the effect of modified atmosphere and humidity generated by two plastic films, microperforated bags (MIPBs) and macroperforated bags (MAPBs), on the levels of phytochemicals present in 'Star Ruby' grapefruits (Citrus paradisi, Macf.) stored for 16 weeks at 10 °C. Control fruits were stored without any packaging film. Juice samples were analyzed every 4 weeks for ascorbic acid, carotenoids, limonoids, flavonoids, and furocoumarins and assessed for quality parameters. MAP significantly reduced weight loss compared to control grapefruits. Control fruits had more β-carotene, lycopene, and furocoumarin compared with the fruits in MAP. Flavonoid content was highest in fruits stored in MAPB (P < 0.05), while fruits stored in MIPB showed no significant difference in flavonoid content compared to control (P > 0.05). The MAP treatments did not significantly affect ascorbic acid, limonoids, or fruit quality parameters, including total soluble solids, acidity, ripening ratio, decay and disorders, fruit taste, and off-flavors after 16 weeks of storage. These results suggest that MAP can be used to maintain the quality of 'Star Ruby' grapefruit with no detrimental effect on health-promoting phytochemicals.

  10. Influence of modified atmosphere packaging on 'Star Ruby' grapefruit phytochemicals.

    PubMed

    Chaudhary, Priyanka R; Jayaprakasha, G K; Porat, Ron; Patil, Bhimanagouda S

    2015-01-28

    Modified atmosphere packaging (MAP) can extend the shelf life of salads, vegetables, and fruits by generating a storage environment with low O2, high CO2, and high humidity. The current study investigates the effect of modified atmosphere and humidity generated by two plastic films, microperforated bags (MIPBs) and macroperforated bags (MAPBs), on the levels of phytochemicals present in 'Star Ruby' grapefruits (Citrus paradisi, Macf.) stored for 16 weeks at 10 °C. Control fruits were stored without any packaging film. Juice samples were analyzed every 4 weeks for ascorbic acid, carotenoids, limonoids, flavonoids, and furocoumarins and assessed for quality parameters. MAP significantly reduced weight loss compared to control grapefruits. Control fruits had more β-carotene, lycopene, and furocoumarin compared with the fruits in MAP. Flavonoid content was highest in fruits stored in MAPB (P < 0.05), while fruits stored in MIPB showed no significant difference in flavonoid content compared to control (P > 0.05). The MAP treatments did not significantly affect ascorbic acid, limonoids, or fruit quality parameters, including total soluble solids, acidity, ripening ratio, decay and disorders, fruit taste, and off-flavors after 16 weeks of storage. These results suggest that MAP can be used to maintain the quality of 'Star Ruby' grapefruit with no detrimental effect on health-promoting phytochemicals. PMID:25547121

  11. Water vapor transport from the Indian monsoon region: the phenomenon of Atmospheric River

    NASA Astrophysics Data System (ADS)

    Raghav R., Sree; Mrudula, G.

    2016-05-01

    An Atmospheric/Tropospheric River (AR/TR) is a relatively narrow corridor of concentrated moisture where horizontal transport occurs in the lower atmosphere. They transport moisture from tropical regions towards the poles across the mid latitudes. Research of Atmospheric River over the Indian Monsoon region is not reported in literature. In this paper an attempt is made to examine the existence of AR in Indian Ocean and surrounding region. Meteorological parameters such as precipitable water, rainfall, air temperature and wind have been analyzed for the same. Analysis shows a clear evidence of the presence of Atmospheric River during the pre-monsoon and monsoon period. It is seen that there are variations in the origin, orientation, duration and also the formation of the river according to the vapor content in the Indian Ocean. During Elnino phase there is a pronounced transport of moisture through an Atmospheric River and also a high intensity transport occurs during monsoon period (JJA), even if moisture prevails over Indian monsoon region during other seasons also. Detailed results and extension to model forecasts will be presented in the paper.

  12. Sensitivity of Boreal-Summer Circulation and Precipitation to Atmospheric Aerosols in Selected Regions. Part 2; The Americas

    NASA Technical Reports Server (NTRS)

    Wilcox, E. M.; Sud, Y. C.; Walker, G.

    2009-01-01

    Aerosol perturbations over selected land regions are imposed in Version-4 of the Goddard Earth Observing System (GEOS-4) general circulation model (GCM) to assess the influence of increasing aerosol concentrations on regional circulation patterns and precipitation in four selected regions: India, Africa, and North and South America. Part 1 of this paper addresses the responses to aerosol perturbations in India and Africa. This paper presents the same for aerosol perturbations over the Americas. GEOS-4 is forced with prescribed aerosols based on climatological data, which interact with clouds using a prognostic scheme for cloud microphysics including aerosol nucleation of water and ice cloud hydrometeors. In clear-sky conditions the aerosols interact with radiation. Thus the model includes comprehensive physics describing the aerosol direct and indirect effects on climate (hereafter ADE and AIE respectively). Each simulation is started from analyzed initial conditions for 1 May and was integrated through June-July-August of each of the six years: 1982 1987 to provide a 6-ensemble set. Results are presented for the difference between simulations with double the climatological aerosol concentration and one-half the climatological aerosol concentration for three experiments: two where the ADE and AIE are applied separately and one in which both the ADE and AIE are applied. The ADE and AIE both yield reductions in net radiation at the top of the atmosphere and surface while the direct absorption of shortwave radiation contributes a net radiative heating in the atmosphere. A large net heating of the atmosphere is also apparent over the subtropical North Atlantic Ocean that is attributable to the large aerosol perturbation imposed over Africa. This atmospheric warming and the depression of the surface pressure over North America contribute to a northward shift of the inter-Tropical Convergence Zone over northern America, an increase in precipitation over Central America

  13. Atmospheric general circulation and its low frequency variance - Radiative influences

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.

    1987-01-01

    The possible effects of radiation on the evolution of the atmosphere on time scales ranging from about a week to about 90 days are examined with reference to the available observational and modeling studies. The clear-sky and cloud radiative processes are shown to exert significant vertical, latitudinal, and longitudinal gradients in the diabatic heating within the troposphere and the stratosphere. The meridional heating gradient, which drives the general circulation, is altered significantly by clouds. The major conclusion of the study is that the observed negative anomalies in the outgoing IR radiation following intense warm episodes of tropicl sea-surface temperature (El Nino) are indeed anomalies in the cloud-radiative forcing.

  14. Atmospheric trace elements over source regions for Chinese dust: concentrations, sources and atmospheric deposition on the Loess plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoye; Arimoto, Richard; An, Zhisheng; Chen, Tuo; Zhang, Guangyu; Zhu, Guanghua; Wang, Xinfu

    The mass-particle size distributions of up to 17 trace elements in aerosol particle samples from dust storm and non-dust storm periods were determined for three sites in or near the source regions of Chinese dust. The mass of particulate material in the atmosphere at the sites is dominated by mineral aerosol particles. An absolute principal component analysis of the non-dust storm elemental data for the loess region allows the estimation of the mass contributions from two coarse-particle classes (soil dust and dust associated with pollutants), and two fine-particle classes (soil dust and anomalously enriched). For most elements (Al, Si, Ca, Fe, Ti, K, S and As), the mass-particle size distributions (MSDs) were approximately log-normal. The mass-median diameters (MMDs) of the soil-derived elements tended to decrease with distance from the desert region and when the dust storms subsided. Total dry deposition velocities were calculated by fitting a log-normal distribution to the aerosol data and calculating deposition rates for 100 particle-size intervals using a two-layer deposition model. The mean dry-deposition rates and fluxes were highest during dust storms over desert regions. In thloess region, the calculated dry deposition velocities of soil derived elements (Al, Si, Ca, Fe and Ti) during non-dust storm periods were from 3.1 to 3.7 cm s -1. From the estimated mass-particles size distributions, the coarser and finer mineral particles were found to benriched with Ca, Fe, Ti and K relative to Al or Si. On a yearly basis, the dry atmospheric input to the Loess Plateau was mainly attributable to normal transport processes, i.e. non-dust storm conditions. Wet deposition fluxes estimated from scavenging ratios indicate that dry deposition dominated the total atmospheric deposition of mineral aerosol. The deposition of aerosol particles associated with coal burning or other anthropogenic sources also was considerable on the Loess Plateau.

  15. Quantifying Carbon-Climate Processes at the Regional Scale Using Atmospheric Carbonyl Sulfide

    SciTech Connect

    Campbell, Elliott; Berry, Joe; Torn, Margaret; David, Billesbach; Seibt, Ulrike

    2013-10-08

    Atmospheric carbonyl sulfide (COS) analysis has the potentially transformative capability for partitioning the regional carbon flux into respiration and photosynthesis components. This emerging approach is based on the observation that continental atmospheric CO2 gradients are dominated by net ecosystem fluxes while continental atmospheric COS gradients are dominated by photosynthesis-related plant uptake. Regional flux partitioning represents a critical knowledge gap due to a lack of robust methods for regional-scale flux partitioning and large uncertainties in forecasting carbon-climate feedbacks. Our completed project characterized the relationship between COS and CO2 surface fluxes using a novel measurement and modeling system in a winter wheat field at the U.S. Department of Energy?s Atmospheric and Radiation Measurement program Central Facility (DOE-ARM CF). The scope of this project included canopy flux measurements, soil flux measurements, regional atmospheric modeling, and analysis of COS and CO2 airborne observations at SGP. Three critical discoveries emerged from this investigation: (1) the new measurement system provided the first field evidence of a robust relationship between COS leaf fluxes and GPP; (2) a previously unknown seasonal soil source of COS was observed and characterized; (3) the regional atmospheric analysis of airborne measurements provided the first COS-based constraints on GPP parameterizations used in earth systems models. Dissemination of these results includes three publications [Billesbach et al., In Press; Campbell et al., In Preparation; Seibt et al., In Review], three presentations at the AGU Fall Meeting (2012), and four invited presentations to department seminars. We have leveraged this foundational project to continue our work on understanding carbon cycle processes at large scales through one funded project (DOE Lab Fee, 2012-2015) and one proposal that is under review (DOE/NASA/USDA/NOAA, 2014-2016).

  16. Tools for determining critical levels of atmospheric ammonia under the influence of multiple disturbances.

    PubMed

    Pinho, P; Llop, E; Ribeiro, M C; Cruz, C; Soares, A; Pereira, M J; Branquinho, C

    2014-05-01

    Critical levels (CLEs) of atmospheric ammonia based on biodiversity changes have been mostly calculated using small-scale single-source approaches, to avoid interference by other factors, which also influence biodiversity. Thus, it is questionable whether these CLEs are valid at larger spatial scales, in a multi- disturbances context. To test so, we sampled lichen diversity and ammonia at 80 sites across a region with a complex land-cover including industrial and urban areas. At a regional scale, confounding factors such as industrial pollutants prevailed, masking the CLEs. We propose and use a new tool to calculate CLEs by stratifying ammonia concentrations into classes, and focusing on the highest diversity values. Based on the significant correlations between ammonia and biodiversity, we found the CLE of ammonia for Mediterranean evergreen woodlands to be 0.69 μg m(-3), below the previously accepted value of 1.9 μg m(-3), and below the currently accepted pan-European CLE of 1.0 μg m(-3).

  17. Permafrost Thaw and Redistribution of Carbon from Lands and Oceans to the Atmosphere: the East Siberian Region

    NASA Astrophysics Data System (ADS)

    Semiletov, I. P.; Shakhova, N. E.; Pipko, I.; Dudarev, O.; Charkin, A.

    2014-12-01

    Unlike other oceans, the Arctic Ocean is completely surrounded by permafrost, which is being degraded at an increasing rate under warming conditions most pronounced in East Siberian region and Alaska. The thaw and release of organic carbon (OC) from Arctic permafrost is postulated to be one of the most powerful mechanisms causing the net redistribution of carbon from lands and oceans to the atmosphere. The East Siberian Arctic shelf (ESAS) is the world's largest continental shelf, containing more than 80 % of the world oceans' subsea permafrost and the largest hydrocarbon reservoir on the planet, while the stability of this sequestered carbon, which exists primarily as CH4, is highly uncertain. This area is heavily influenced by subsea permafrost thaw, and CH4 seeps from subsea permafrost reservoirs under warming conditions. Various other phenomena influence the area, including coastal erosion, mostly caused by onshore permafrost/coastal ice complex thaw; the input of dissolved and particulate OC through the Lena, Indigirka, and Kolyma rivers. The ESAS is also of particular interest for its carbon-climate couplings because thawing of onshore and offshore permafrost leads to the CH4 and CO2 emission to the atmosphere. The overall goal of the current research is to provide a quantitative, observation-based assessment of the dynamics of different ESAS carbon cycle components with emphasize on the emission of CO2 and CH4 to the atmosphere under changing climatic and environmental conditions.

  18. Influence of atmospheric waves on the formation and maintenance of

    NASA Astrophysics Data System (ADS)

    Kuroda, Yuhji

    2016-04-01

    The formation and maintenance of the subtropical jet during the Northern Hemisphere winter was examined using new analysis method that can isolate the responses to specific forcings within meteorological data. It is found that atmospheric waves play a crucial role in the climatological maintenance, the month-to-month, and the day-to-day variabilities of the jet. Climatologically, stationary waves, which reach up to 1.4 m/s/day, are the greatest accelerator of the jet core, whereas synoptic waves decelerate the jet core. For the month-to-month variability of the jet, stationary waves are the primary driver of the jet, followed by synoptic waves. On the other hand, Low-Frequency Transient (LFT) waves, whose frequency falls between stationary and synoptic waves, act to suppress the variability. However, synoptic waves play a key role in creating the variability on a monthly scale, whereas stationary waves work only for the maintenance of the jet. Regarding the day-to-day variability of the jet, the most important driver of eddies originates from the interference between synoptic waves and the mixing of stationary and LFT waves.

  19. Developing a broad spectrum atmospheric aerosol characterization for remote sensing platforms over desert regions

    NASA Astrophysics Data System (ADS)

    Strong, Shadrian B.; Brown, Andrea M.

    2014-05-01

    Remotely sensed imagery of targets embedded in Earth's atmosphere requires characterization of aerosols between the space-borne sensor and ground to accurately analyze observed target signatures. The impact of aerosol microphysical properties on retrieved atmospheric radiances has been shown to negatively affect the accuracy of remotely sensed data collects. Temporally and regionally specific meteorological conditions require exact site atmospheric characterization, involving extensive and timely observations. We present a novel methodology which fuses White Sands New Mexico regional aerosol micro pulse lidar (MPL) observations with sun photometer direct and diffuse products for broad-wavelength (visible - longwave infrared) input into the radiative transfer model MODTRAN5. Resulting radiances are compared with those retreived from the NASA Aqua MODIS instrument.

  20. The atmospheric frontal response to SST perturbations in the Gulf Stream region

    NASA Astrophysics Data System (ADS)

    Parfitt, Rhys; Czaja, Arnaud; Minobe, Shoshiro; Kuwano-Yoshida, Akira

    2016-03-01

    The link between sea surface temperature (SST) gradients and atmospheric fronts is explored in a general circulation model across the Gulf Stream (GS) region from December to February 1981-2000. Two model experiments are analyzed, one with a realistic control SST distribution and one with a spatially smoothed SST distribution. The analysis shows a noticeable change in regional atmospheric frontal frequency between the two experiments (up to 30%), with the distribution of change exhibiting a clear imprint of the GS SST front. Further analysis of the surface sensible heat flux gradient across cold fronts reveals the pattern of change to be mediated by a thermal interaction between the oceanic and atmospheric fronts ("thermal damping and strengthening"). These results not only emphasize the significance of the GS SST gradient for storm development in the North Atlantic but also highlight the importance of resolution in assessing the role of frontal air-sea interaction in midlatitude climate variability.

  1. Comparative influences of airborne pollutants and meteorological parameters on atmospheric visibility and turbidity

    NASA Astrophysics Data System (ADS)

    Wen, Chih-Chung; Yeh, Hui-Hsuan

    2010-06-01

    The purpose of this paper was to investigate how atmospheric air pollutants and meteorological conditions affect atmospheric visibility and turbidity. Meteorological parameter and anthropogenic air pollutant values were recorded during 2004 and 2005 at the Wuchi weather station and the Sha-lu environmental quality database station at the Taichung Harbor near the Taiwan Strait. Local weather conditions (temperature, relative humidity and solar radiation) and airborne pollutant (PM 10, SO 2, NO 2, CO and O 3) concentrations were used to analyze the relative effects of atmospheric air pollutants and meteorological conditions on atmospheric visibility and turbidity. Based on the analytic results, air pollutant concentrations significantly influence visibility and atmospheric turbidity. Wind speed is an important meteorological parameter that affects atmospheric turbidity parameters at the same atmospheric air pollutant concentrations throughout the periods of observation. At wind speeds of greater than 7 m/s, the turbidity factor β Vis is below 0.3 and visibility is greater than 6.5 km. Under very turbid conditions, β Vis > 0.4, the wind velocity is below 5 m/s, regardless of the atmospheric pollutant concentration. When visibility is ≥ 11 km, the PM 10 concentration is predicted to be below 150 μg/m 3 and the atmosphere is regarded as clear. Under very turbid conditions, the PM 10 concentration exceeds 250 μg/m 3.

  2. Large gradients in aerosol induced atmospheric heating rate over oceanic regions around India: Results from the ICARB Experiment of ISRO-GBP

    NASA Astrophysics Data System (ADS)

    Babu, S. Suresh; Krishna Moorthy, K.; Nair, Vijayakumar S.; K, Satheesh S.

    The importance of aerosol absorption and the resulting heating of the lower atmosphere over south Asia are being increasingly investigated in the context of regional and global climate implications. Even though significant abundance of absorbing aerosols has been measured over the oceanic regions around India, studies addressing its spatial and vertical distributions and radiative impacts are sparse. Most of the regional-climate impacts assessments are mainly based on the Indian Ocean Experiment (INDOEX) data or using the chemical transport model simulations. In the backdrop of the regional climate implications of absorbing aerosols, exten-sive, spatially resolved measurements of aerosol microphysical properties were made onboard research ship and aircraft during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) as a part of ISRO -Geosphere Biosphere Program. Aerosol parameters within the marine atmospheric boundary layer (MABL), free troposphere and in the entire column clearly depict large gradient along the latitudes and longitudes. Using these concurrent measurements of the aerosol properties, atmospheric radiative forcing and heating rates were estimated for a spatial resolution of 1 by 1. The spatial distribution of aerosol heating rate showed very high ( 0.5 K day per day) values over the northern Bay of Bengal and very low (¡ 0.1 K per day) values over the southeastern Arabian Sea. Similarly, aircraft measurements also showed an increase in the amplitude and strength of the elevated aerosol layers from south to north direction. Very high values of heating rate above the MABL modifies the thermody-namics structure of the atmosphere, which influence the stability of the lower troposphere and thus the hydrological cycle over the region. These gradients in atmospheric heating induced by aerosols will significantly influence the synoptic circulations over the regions when the winds are in transition from northeasterly to southwesterly

  3. Understanding hydrologic sensitivity and land-atmosphere interactions through remote sensing and high resolution regional model

    NASA Astrophysics Data System (ADS)

    Kumar, Anil

    2016-05-01

    In this study we investigated the impact of land surface surface process & land-atmospheric interaction on weather and surface hydrology. The ultimate goal is to integrate remote sense data into numerical mesoscale weather prediction and regional climate model in order to improve prediction of the impacts of land-atmosphere interactions and land-surface processes on regional weather, and hydrology. We have used climatology based green vegetation fraction and 8-day Moderate Resolution Imaging Spectroradiometer (MODIS) based green vegetation fraction and integrated in the Land Information System to conduct uncoupled simulation to understand the impact on surface and hydrological parameters in the summer season. The vegetation response is also realized through coupled regional climate simulation in which climatological based greenness and 8-days varying vegetation is investigated and quantify the impact of vegetation on summertime precipitation process. This study has bought following findings (a) Satellite based vegetation indices captures vegetation temporal patterns more realistic than climatological vegetation data and detects early/late spring signature through vegetation indices, (b) Integrated satellite vegetation greenness input data in regional weather model resolved much better soil moisture and soil temperature including the diurnal cycle of surface heat fluxes and surface temperature in the simulation. Secondly, integration of the TRMM based satellite rainfall product into coupled hydrological and Atmospheric model and results shows better resolved soil moisture patterns in the remote regions of the Asia Mountain regions.

  4. Influence of atmospheric deposition on Okefenokee National Wildlife Refuge

    SciTech Connect

    Winger, P.V.; Lasier, P.J.; Jackson, B.P.

    1995-12-31

    Designation of Okefenokee National Wildlife Refuge (Georgia) as a Class 1 Air Quality Area affords mandatory protection of the airshed through permit-review processes for planned developments. Rainfall is the major source of water to the swamp, and potential impacts from developments in the airshed are high. To meet management needs for baseline information, chemical contributions from atmospheric deposition and partitioning of anions and cations in various matrices of the swamp, with emphasis on mercury and lead, were determined during this study. Chemistry of rainfall was measured on an event basis from one site and quarterly on surface water, pore water, floc, and sediment from four locations. A sediment core collected from the Refuge concentrations of 9 ng/L and 0.1 ng/L, respectively. Surface waters were acidic (pH 4.7--4.9), with average total and methyl mercury highly organic (dissolved organic carbon 35--50 mg/L). Total mercury was 1--3.5 ng/L in surface and pore water, and methyl mercury was 0.02--0.20 ng/L. Total mercury in sediments and floc was 100--200 ng/g dry weight, and methyl mercury was 4--16ng/g. Lead was 0--1.7 {micro}g/L in rainfall, not detectable in surface water, 3.4--5.4 {micro}g/L in pore water, and 3.9--4.9 mg/kg in floc and sediment. Historical patterns of mercury deposition showed an increase in total mercury from pre-1800 concentrations of 250 ng/g to 500 ng/g in 1950, with concentrations declining thereafter to present.

  5. Snow-atmosphere coupling and extremes over North America in the Canadian Regional Climate Model (CRCM5)

    NASA Astrophysics Data System (ADS)

    Diro, G. T.; Sushama, L.; Huziy, O.

    2015-12-01

    Given the importance of land in the climate system, we investigate the influence of land surface, in particular the variation in snow characteristics, on climate variability and extremes over North America using the fifth generation of Canadian Regional Climate Model (CRCM5). To this end, we carried out two CRCM5 simulations driven by ERA-Interim reanalysis, where snow is either prescribed (uncoupled) or evolves interactively (coupled) during the model integration. Results indicate a systematic influence of snow on the inter-annual variability of air and surface temperature throughout the winter and spring seasons. In the coupled simulations, where the snow depth and snow cover were allowed to evolve freely, the inter-annual variability of surface and near surface air temperatures were found to be larger. Comparison with the uncoupled simulation suggests that snow depth/cover variability accounts for about 70% of the total surface temperature variability over the northern Great Plains and Canadian Prairies for the winter and spring seasons. The snow-atmosphere coupling is stronger in spring than in winter, since in spring season both the albedo and the latent heat flux contribute to the variability in temperature. Snow is also found to modulate extreme temperature events such as the number of cold days over Prairies during weak La-Nina episodes. These results suggest that initializing forecast models with realistic snow condition could potentially help to improve seasonal/sub-seasonal prediction skill over these snow-atmosphere coupling hotspot regions.

  6. The Influence of Tropospheric Processes in Modeling the Middle Atmosphere with Gravity Waves

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G.; Drob, D. P.; Porter, H. S.

    2002-01-01

    Our Numerical Spectral Model (NSM) extends from the ground up into the thermosphere and has a vertical grid point resolution of about 0.5 km to resolve the interactions of gravity waves (GWs) described with Hines' Doppler Spread Parameterization (DSP). This model produces in the stratosphere and mesosphere the major features of QBO, SAO, tides, and planetary waves. The purpose of this paper is to discuss results from an initial study with our 3D model that shows how certain tropospheric processes can affect the dynamics of the middle atmosphere. Under the influence of tropospheric heating, and augmented by GW interactions, two distinct but related processes can be identified. (1) A meridional circulation develops in the stratosphere, with rising motions at low latitudes that are in magnitude comparable to the downward propagation of the QBO. As Dunkerton pointed out, a larger GW source is then required to reproduce the observed QBO, which tends to move us closer to the values recommended for the DSP. This has significant consequences for our model results that describe the upper mesosphere, considering the general importance of GWs for this region and in influencing planetary waves (e.g., 2-day wave) and tides in particular. (2) Tropospheric heating produces zonal jets near the tropopause that are related to latitudinal variations in pressure and reversing temperature variations (resembling the dynamical conditions near the mesopause), which in turn is conducive to generate baroclinic instability. Modeling results show that our ability to generate the QBO critically depends on the magnitude of the temperature reversal that is a measure of this instability. Planetary waves are generated in this process, which can apparently interfere with or augment the GW interactions. As originally demonstrated by Lindzen and Holton, the eastward propagating Kelvin waves and westward propagating Rossby gravity waves (generated by tropospheric convection) can in principle provide

  7. The influence of north Pacific atmospheric circulation on streamflow in the west

    USGS Publications Warehouse

    Cayan, Daniel R.; Peterson, David H.

    1989-01-01

    The annual cycle and nonseasonal variability of streamflow over western North America and Hawaii is studied in terms of atmospheric forcing elements. This study uses several decades of monthly average streamflow beginning as early as the late 1800's over a network of 38 stations. In addition to a strong annual cycle in mean streamflow and its variance at most of the stations, there is also a distinct annual cycle in the autocorrelation of anomalies that is related to the interplay between the annual cycles of temperature and precipitation. Of particular importance to these lag effects is the well-known role of water stored as snow pack, which controls the delay between peak precipitation and peak flow and also introduces persistence into the nonseasonal streamflow anomalies, with time scales from 1 month to over 1 year. The degree to which streamflow is related to winter atmospheric circulation over the North Pacific and western North America is tested using correlations with time averaged, gridded sea level pressure (SLP), which begins in 1899. Streamflow fluctuations show significant large-scale correlations for the winter (December through February) mean SLP anomaly patterns over the North Pacific with maximum correlations ranging from 0.3 to about 0.6. For streams along the west coast corridor the circulation pattern associated with positive streamflow anomalies is low pressure centered off the coast to the west or northwest, indicative of increased winter storms and an anomalous westerly-to-southwesterly wind component. For streams in the interior positive streamflow anomalies are associated with a positive SLP anomaly stationed remotely over the central North Pacific, and with negative but generally weaker SLP anomalies locally. One important influence on streamflow variability is the strength of the Aleutian Low in winter. This is represented by the familiar Pacific-North America (PNA) index and also by an index defined herein the “CNP” (Central North

  8. Evaluating Direct Radiative Effects of Absorbing Aerosols on Atmospheric Dynamics with Aquaplanet and Regional Model Results

    NASA Astrophysics Data System (ADS)

    Can, Ö.; Tegen, I.; Quaas, J.

    2015-12-01

    Effects of absorbing aerosol on atmospheric dynamics are usually investigated with help of general circulation models or also regional models that represent the atmospheric system as realistic as possible. Reducing the complexity of models used to study the effects of absorbing aerosol on atmospheric dynamics helps to understand underlying mechanisms. In this study, by using ECHAM6 General Circulation Model (GCM) in an Aquaplanet setting and using simplified aerosol climatology, an initial idealization step has been taken. The analysis only considers direct radiative effects, furthering the reduction of complex model results. The simulations include cases including aerosol radiative forcing, no aerosol forcing, coarse mode aerosol forcing only (as approximation for mineral dust forcing) and forcing with increased aerosol absorption. The results showed that increased absorption affects cloud cover mainly in subtropics. Hadley circulation is found to be weakened in the increased absorption case. To compare the results of the idealized model with a more realistic model setting, the results of the regional model COSMO-MUSCAT that includes interactive mineral dust aerosol and considers the effects of dust radiative forcing are also analyzed. The regional model computes the atmospheric circulation for the year 2007 twice, including the feedback of dust and excluding the dust aerosol forcing. It is investigated to which extent the atmospheric response to the dust forcing agrees with the simplified Aquaplanet results. As expected, in the regional model mineral dust causes an increase in the temperature right above the dust layer while reducing the temperature close to the surface. In both models the presence of aerosol forcing leads to increased specific humidity, close to ITCZ. Notwithstanding the difference magnitudes, comparisons of the global aquaplanet and the regional model showed similar patterns. Further detailed comparisons will be presented.

  9. Non-stationarities in land-atmosphere-climate interactions in Europe and the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Romberg, Karin; Hertig, Elke; Jacobeit, Jucundus

    2016-04-01

    Interactions between the land surface and the atmosphere are of major importance for the regional and global climate. Soil moisture thereby plays a key role: availability of water in the soils is one of the drivers of evaporation and thus impacts on temperature and precipitation. Regions of strong soil moisture-atmosphere coupling include the Mediterranean area while in other regions of Europe non-local effects such as the advection of dry (moist) air are more important. However, previous studies have also shown that climate is fundamentally non-stationary and that such non-stationarities occur on various spatial and temporal scales. These studies have mainly focused on sea-surface-atmosphere interactions or circulation-climate interactions. Thus, the question arises whether soil-moisture-atmosphere-climate interactions also show a non-stationary behavior. As a first step, Varimax-rotated s-mode principal component analysis (PCA) is used to reduce dimensions of soil moisture fields, circulation variables as well as of 2m temperature fields. The resulting PC loadings represent the spatial patterns while the PC scores are the corresponding time coefficients. For the analysis of non-stationarities, the time coefficients of soil moisture and temperature are further used in 30-year running correlation and feedback parameter analyses. Furthermore, correlation analyses are carried out for the circulation variables and soil moisture or temperature, as changes of the atmospheric circulation are a potential source of non-stationarities. All analyses focus on the boreal summer season 1950-2009. Results show substantial non-stationaries in the relationship between soil moisture and temperature in several regions in the European and Mediterranean domain. Depending on the region considered, these changes are accompanied by modifications in different large-scale circulation patterns such as the North Atlantic Oscillation, the Scandinavia pattern or a high pressure system centered

  10. Toward the predictability of meteotsunamis in the Balearic Sea using regional nested atmosphere and ocean models

    NASA Astrophysics Data System (ADS)

    Renault, Lionel; Vizoso, Guillermo; Jansá, Agustin; Wilkin, John; Tintoré, Joaquin

    2011-05-01

    Meteotsunamis are oceanic waves that possess tsunami-like characteristics but are meteorological in origin. In the western Mediterranean, travelling atmospheric pressure oscillations generate these long oceanic surface waves that can become amplified and produce strong seiche oscillations inside harbors. We analyze a June 2006 meteotsunami event in Ciutadella harbor (Menorca Island, Spain), studying numerically the phenomenon during its full life cycle, from the early atmospheric stages to the atmosphere-ocean resonant phase and the final highly amplified harbor oscillation. The Weather Research Forecast (WRF) atmospheric model adequately reproduces the development of a convective nucleus and also reproduces the induced atmospheric pressure oscillations moving at a speed of 27 m/s. The oceanic response is studied using the Regional Ocean Modeling System (ROMS), forced by the WRF pressure field. It shows an inverse barometer wave front in the open ocean progressively amplified through resonant interactions in the different shelf and coastal regions. The predictive capability of this new WRF/ROMS modeling approach is then discussed.

  11. Processes influencing rainfall features in the Amazonian region

    NASA Astrophysics Data System (ADS)

    Gerken, T.; Chamecki, M.; Fuentes, J. D.; Katul, G. G.; Fitzjarrald, D. R.; Manzi, A. O.; Nascimento dos Santos, R. M.; von Randow, C.; Stoy, P. C.; Tota, J.; Trowbridge, A.; Schumacher, C.; Machado, L.

    2014-12-01

    The Amazon is globally unique as it experiences the deepest atmospheric convection with important teleconnections to other parts of the Earth's climate system. In the Amazon Basin a large fraction of the local evapotranspiration is recycled through the formation of deep convective precipitating storms. Deep convection occurs due to moist thermodynamic conditions associated with elevated amounts of convective available potential energy. Aerosols invigorate the formation of convective storms in the Amazon via their unique concentrations, physical size, and chemical composition to activate into cloud condensation nuclei (CCN), but important aspects of aerosol/precipitation feedbacks remain unresolved. During the wet season, low atmospheric aerosol concentrations prevail in the pristine tropical air masses. These conditions have led to the Green Ocean hypothesis, which compares the clean tropical air to maritime air-masses and emphasizes biosphere-atmosphere feedbacks, to explain the features of the convective-type rainfall events in the Amazon. Field studies have been designed to investigate these relationships and the development of mesoscale convective systems through the Green Ocean Amazon project and the GOAmazon Boundary Layer Experiment. From March to October 2014 a field experiment was conducted at the Cuieiras Biological Reserve (2°51' S, 54°58' W), 80 km north of the city of Manaus, Brazil. This investigation spans the biological, chemical, and physical conditions influencing emissions and reactions of precursors (biogenic and anthropogenic volatile organic compounds, VOCs), formation of aerosols and CCNs and transport out of the ABL, and their role in cloud formation and precipitation triggers. In this presentation we will show results on the magnitude turbulent fluxes of latent and sensible heat, CCN concentrations, and rain droplet size distribution for both the wet and dry season. Such influencing factors on precipitation, will be contrasted with the

  12. Distinct atmospheric patterns and associations with acute heat-induced mortality in five regions of England.

    PubMed

    Petrou, Ilias; Dimitriou, Konstantinos; Kassomenos, Pavlos

    2015-10-01

    The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed.

  13. Distinct atmospheric patterns and associations with acute heat-induced mortality in five regions of England.

    PubMed

    Petrou, Ilias; Dimitriou, Konstantinos; Kassomenos, Pavlos

    2015-10-01

    The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed. PMID:25605407

  14. Vertical variations in the influence of the amount effect: South American Summer Monsoon Region

    NASA Astrophysics Data System (ADS)

    Samuels-Crow, K. E.; Galewsky, J.; Worden, J. R.

    2014-12-01

    Recent theoretical studies have shown that convective recycling of atmospheric water vapor gives rise to the isotope "amount effect" in which d values are lower than predicted by simple Rayleigh distillation processes (i.e. (DdD = dDvapor ­- dDRayleigh < 0‰). Several studies have linked isotopes in precipitation [e.g. Vimeux et al., 2009] and atmospheric water vapor [e.g. Samuels-Crow et al., 2014] in the tropical Andes to upwind convection associated with the South American Summer Monsoon (SASM). The vertical structure of this convective influence, however, remains unknown. Understanding the vertical structure of the amount effect over South America is essential for improving theoretical constraints and developing better models of the influence of the SASM on southern hemisphere humidity. Additionally, evaluating the vertical and lateral extent of the SASM's convective influence can provide important constraints for interpreting paleoclimate proxies in the region. We use data from the Tropospheric Emission Spectrometer (TES) to examine the vertical structure of the amount effect associated with the SASM and relate these results to regional convective precipitation and local subcloud equivalent potential temperature. Preliminary results show that DdD is below 0‰ from the boundary layer through the mid-troposphere over tropical South America during austral summer, and meridional averages show that convective precipitation is highest over these areas where DdD < 0‰ extends higher in the atmosphere. We hypothesize that the depth of convection in the monsoon region controls the vertical structure of DdD, which should also be coherently linked to local equivalent potential temperature. References Vimeux et al. (2009), Palaeogeogr Palaeocl, 281(3-4), 229-241, doi:10.1016/j.palaeo.2008.03.054. Samuels-Crow et al. (2014), J Geophys Res-Atmos, doi:10.1002/(ISSN)2169-8996.

  15. Intra-annual variation of atmospheric static stability in the Mediterranean region: a 60-year climatology

    NASA Astrophysics Data System (ADS)

    Lolis, C. J.; Bartzokas, A.; Lagouvardos, K.; Metaxas, D. A.

    2012-10-01

    The seasonal characteristics of atmospheric static stability in the Mediterranean region are examined, for the 60-year period 1948-2007 and for the four 15-year sub-periods 1948-1962, 1963-1977, 1978-1992 and 1993-2007. S-Mode and T-Mode Factor Analysis are applied to the mean 5-day values of K static stability index over the Mediterranean region. Three dominant modes are revealed for both, the intra-annual variation and the spatial distribution of K-index. It is found that these modes are connected to the seasonal characteristics of the main atmospheric circulation systems affecting the region and the thermal properties of the Earth's surface (land or sea). The differences among the results of the four sub-periods partially reflect the inter-decadal variations of the strength of the above factors.

  16. Improved PPP Ambiguity Resolution Considering the Stochastic Characteristics of Atmospheric Corrections from Regional Networks

    PubMed Central

    Li, Yihe; Li, Bofeng; Gao, Yang

    2015-01-01

    With the increased availability of regional reference networks, Precise Point Positioning (PPP) can achieve fast ambiguity resolution (AR) and precise positioning by assimilating the satellite fractional cycle biases (FCBs) and atmospheric corrections derived from these networks. In such processing, the atmospheric corrections are usually treated as deterministic quantities. This is however unrealistic since the estimated atmospheric corrections obtained from the network data are random and furthermore the interpolated corrections diverge from the realistic corrections. This paper is dedicated to the stochastic modelling of atmospheric corrections and analyzing their effects on the PPP AR efficiency. The random errors of the interpolated corrections are processed as two components: one is from the random errors of estimated corrections at reference stations, while the other arises from the atmospheric delay discrepancies between reference stations and users. The interpolated atmospheric corrections are then applied by users as pseudo-observations with the estimated stochastic model. Two data sets are processed to assess the performance of interpolated corrections with the estimated stochastic models. The results show that when the stochastic characteristics of interpolated corrections are properly taken into account, the successful fix rate reaches 93.3% within 5 min for a medium inter-station distance network and 80.6% within 10 min for a long inter-station distance network. PMID:26633400

  17. Long-range atmospheric transport of heavy metals from industrial regions of Ural and Norilsk to siberian environment

    NASA Astrophysics Data System (ADS)

    Vinogradova, Anna; Maksimenkov, Leonid; Pogarskii, Fedor

    2010-05-01

    The main idea of the work is to analyze atmospheric transport of heavy metals (Ni, Cu, Pb) from the industries of the region of Norilsk, and the Ural over the territory of Siberia. The basic data were 5-days air mass trajectories from the sources calculated for every day of January, April, July, and October during 28 years from 1981 to 2008. NCEP/NCAR Reanalysis Data Files and HYSPLIT 4 model were used. Spatial, seasonal and long-term variations in heavy metal (HM) concentrations in surface air and precipitations, as well as in fluxes of these elements onto the surface were studied. The obtained results (presented as maps) may be used as assessment of anthropogenic influence of the sources under investigation on the environment of remote and hard-to-reach areas. The HM air concentrations and fluxes onto the surface depend on surface properties and precipitation regime, and experience great seasonal and spatial variations. The maximal air concentrations are in cold seasons, whereas the maximal fluxes onto the surface occur in warm period. In comparison anthropogenic loadings at different places the cleanest air does not guarantees the minimal vertical fluxes. The pollution trends (modulo) caused only by the transformation of air circulation processes are quite comparable with the contributions of source-emissions' changes. The main result is the decreasing of Siberian environment pollution through the atmosphere from regarded sources during the last years. At a distance about 2000 km from a large source under investigation its atmospheric emissions form only the background levels of HM in the surface environment, and the real pollution levels are determined by local anthropogenic sources (with less emissions) if they exist. So, for the Lake Baikal the HM inputs from our distant sources through atmosphere to the water surface are insignificant in comparison with the flowing rivers' ones, and lake water pollution occurs mainly due to rivers' pollution. However, annual

  18. Contributions of long-range and regional atmospheric transport on pesticide concentrations along a transect crossing a mountain divide.

    PubMed

    Lavin, Karen S; Hageman, Kimberly J

    2013-02-01

    Twenty-one halogenated legacy and current-use pesticides and pesticide degradation products were measured in pine needles along a coast-to-coast transect that crossed the Southern Alps of New Zealand. Concentration profiles of nine pesticides were used to determine the influence of geographic sources on the atmospheric pesticide burden at the mountain sites. Pesticide concentration profiles were calculated for each source and mountain site by normalizing concentrations (adjusted for temperature at the site and air-needle partitioning) to the sum of all pesticide concentrations at the site. Each mountain site profile was compared to varying mixtures of the potential source profiles to determine the percent contribution of each source. The highest elevation mountain sites were primarily influenced by long-range, synoptic-scale northwesterly winds. Westerly upslope winds had little influence on any of the mountain sites. Easterly upslope winds from the Canterbury Plains, an agricultural region, strongly influenced the mountain sites within close proximity and had progressively less influence with distance.

  19. A profile of UK unemployment: regional versus demographic influences.

    PubMed

    Brown, S; Sessions, J G

    1997-06-01

    "This paper profiles the incidence of unemployment in the [United Kingdom] over the period 1985-91 using data derived from the British Social Attitudes Survey. The approach of the paper is to quantify the differential probabilities of unemployment faced by particular groups within the population, focusing in particular on the relative effects of demographic and regional influences. Our results indicate that, even after controlling for a plethora of demographic characteristics, regional disparities in unemployment risk are prevalent, with individuals in Northern Ireland, Wales, the North and West Midlands of England facing a higher chance of unemployment ceteris paribus." (EXCERPT) PMID:12293417

  20. Ionospheric irregularities in the low-latitude valley region observed with the Equatorial Atmosphere Radar

    NASA Astrophysics Data System (ADS)

    Yokoyama, T.; Patra, A. K.; Fukao, S.; Yamamoto, M.

    2005-10-01

    The geomagnetically low-latitude valley region between the upper E region and the lower F1 region is studied with the Equatorial Atmosphere Radar (EAR) in Indonesia. Three-meter-scale field-aligned irregularity echoes have been frequently observed in the valley region in association with the equatorial spread F (ESF) in the period from sunset to midnight. The valley region echoes usually appear at above 150 km and propagate downward with time. Rapid beam scanning of the EAR revealed that spatial structure, temporal variation, and drift velocity of the valley region echoes resemble those of ESF, which indicates that the dynamoelectric field in the equatorial F region controls the low-latitude valley region irregularities. Perturbed electric fields associated with ESF map down to the low-latitude valley region and can produce the perturbed plasma density structures as "images" of ESF structures. Image structure is effectively formed at altitudes below 200 km and is a source of the valley region irregularities observed with the EAR. It is suggested that intermediate layers should supply a plasma density gradient for excitation of 3-m-scale irregularities in the valley region through gradient drift instability.

  1. Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

    NASA Astrophysics Data System (ADS)

    Yasakau, K. A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M. G. S.; Zheludkevich, M. L.

    2016-12-01

    In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

  2. Regional atmospheric circulation over Europe during the Last Glacial Maximum and its links to precipitation

    NASA Astrophysics Data System (ADS)

    Ludwig, Patrick; Schaffernicht, Erik; Shao, Yaping; Pinto, Joaquim

    2016-04-01

    The Last Glacial Maximum (LGM) exhibits different large-scale atmospheric patterns compared to present-day climate due to altered boundary conditions. The impacts on the regional atmospheric circulation and associated precipitation patterns over Europe for the LGM are characterized for the first time with a weather typing approach (circulation weather types, CWT) from (paleo-) climate simulations. While the CWTs over Western Europe are prevailing westerly for both present-day and LGM conditions, considerable differences are identified elsewhere: Southern Europe experienced more frequent westerly and cyclonic CWTs under LGM conditions, while Central and Eastern Europe was predominantly affected by southerly and easterly flow patterns. Precipitation patterns under LGM conditions show increased rainfall in Western Europe but are reduced over most of Central and Eastern Europe. These differences are explained by changing CWT frequencies and evaporation patterns over the North Atlantic Ocean. The regional differences of the CWTs and precipitation patterns are linked to the North Atlantic storm track, which was stronger over Europe in all considered models during LGM, explaining the overall increase of the cyclonic CWT. Enhanced evaporation over the North Atlantic lead to an increased amount of available moisture over the ocean. Despite the overall cooling during the LGM, this explains the enhanced precipitation amounts over southwestern parts of Europe, particularly Iberia. This study links large scale atmospheric dynamics to the regional circulation and associated precipitation patterns and provides an improved regional assessment for climate conditions in Europe under LGM conditions.

  3. Infrasound Sensor Coverage at Regional Ranges as driven by the Atmospheric State

    NASA Astrophysics Data System (ADS)

    Norris, D.

    2010-12-01

    Infrasound is an attractive regional sensor modality in explosion monitoring applications due to its non line-of-sight, long-range detection capability. Anthropomorphic activity, including impulsive events such as explosions and continuous events such as vehicle operation, can be routinely detected over tens of kilometer ranges and beyond. This study addresses the issues associated with effectively leveraging infrasound for regional monitoring applications. A key challenge in applying infrasound at these ranges is adequately understanding the propagation. Spatial and temporal features of the atmospheric state create evolving regions of acoustic focusing and shadowing at the surface. Understanding this acoustic "footprint" and having the capability to predict it over time is necessary for two reasons. It drives the planning process of where to deploy a given permanent or temporary suite of infrasound sensors. In addition, knowing the observability of a stationary or mobile source supports the interpretation of operational data. This research includes a sample study on characterization of atmospheric effects on regionally deployed infrasound networks. Predictions are made from real atmospheric states to illustrate the range of observability conditions that may occur. It was found that the observability can have significant frequency dependence.

  4. Mapping Distant Continental Influences in the Remote Pacific Atmosphere; Simulations of CO Relevant to the Photochemistry of Oxidants

    NASA Technical Reports Server (NTRS)

    Chatfield Robert B.; Guo, Z.; Sachse, G.; Singh, H.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    An animated sequence of maps of simulated carbon monoxide concentrations graphically portrays the extent of residual continental influence upon the tropical Pacific Ocean as studied by NASA aircraft during the PEM-Tropics B intensive sampling campaign. We used the MM5 at a 90 km resolution in a globally wrapped grid to simulate the meteorology of transport, and our GRACES model to follow the basic chemistry. The CO we simulate derives from different sources, and so we distinguish anthropogenic, natural terpenoid oxidation, biomass burning, and pervasive CH4-oxidation influences. "Influence" is always judged with an implicit timescale, and these maps describe influence on the 15-45 day timescale appropriate for CO oxidation. In consequence, the maps are useful in assessing the origins of slowly reacting compounds like acetone, methanol, and the lightest hydrocarbons. At 8 km altitude, The Eastern South Pacific to ca. 130 W (eastern Polynesia) was frequently affected by continental influences but NASA's DC-8's flight path did not happen to take it into these regions very often. Near the surface, continentally influenced air crossed into t he Western South Pacific, in the region northwest of the Southern Pacific Convergence Zone but south of the Intertropical Convergence Zone. This air originated from the NE Pacific, and partly from North America. Comparisons are made to CO and other compounds measured aboard the DC-8 and the P-3 aircraft. We will also use tracers to describe the influence of marine convection in the upper troposphere. As time allows, we will discuss the "age" of ozone within the very cleanest region sampled in portions of the near-equatorial Western South Pacific, using a simple chemical mechanism for ozone levels. These simulations describe the chemistry of an atmosphere with very low ozone.

  5. Charge structure of a summer thunderstorm in North China: Simulation using a Regional Atmospheric Model System

    NASA Astrophysics Data System (ADS)

    Liu, Dongxia; Qie, Xiushu; Peng, Liang; Li, Wanli

    2014-09-01

    Electrification and simple discharge schemes are coupled into a 3D Regional Atmospheric Model System (RAMS) as microphysical parameterizations, in accordance with electrical experiment results. The dynamics, microphysics, and electrification components are fully integrated into the RAMS model, and the inductive and non-inductive electrification mechanisms are considered in the charging process. The results indicate that the thunderstorm mainly had a normal tripole charge structure. The simulated charge structure and lightning frequency are basically consistent with observations of the lightning radiation source distribution. The non-inductive charging mechanism contributed to the electrification during the whole lifetime of the thunderstorm, while the inductive electrification mechanism played a significant role in the development period and the mature stage when the electric field reached a large value. The charge structure in the convective region and the rearward region are analyzed, showing that the charge density in the convective region was double that in the rearward region.

  6. Influence of atmospheric properties on detection of wood-warbler nocturnal flight calls.

    PubMed

    Horton, Kyle G; Stepanian, Phillip M; Wainwright, Charlotte E; Tegeler, Amy K

    2015-10-01

    Avian migration monitoring can take on many forms; however, monitoring active nocturnal migration of land birds is limited to a few techniques. Avian nocturnal flight calls are currently the only method for describing migrant composition at the species level. However, as this method develops, more information is needed to understand the sources of variation in call detection. Additionally, few studies examine how detection probabilities differ under varying atmospheric conditions. We use nocturnal flight call recordings from captive individuals to explore the dependence of flight call detection on atmospheric temperature and humidity. Height or distance from origin had the largest influence on call detection, while temperature and humidity also influenced detectability at higher altitudes. Because flight call detection varies with both atmospheric conditions and flight height, improved monitoring across time and space will require correction for these factors to generate standardized metrics of songbird migration.

  7. Influence of atmospheric properties on detection of wood-warbler nocturnal flight calls

    NASA Astrophysics Data System (ADS)

    Horton, Kyle G.; Stepanian, Phillip M.; Wainwright, Charlotte E.; Tegeler, Amy K.

    2015-10-01

    Avian migration monitoring can take on many forms; however, monitoring active nocturnal migration of land birds is limited to a few techniques. Avian nocturnal flight calls are currently the only method for describing migrant composition at the species level. However, as this method develops, more information is needed to understand the sources of variation in call detection. Additionally, few studies examine how detection probabilities differ under varying atmospheric conditions. We use nocturnal flight call recordings from captive individuals to explore the dependence of flight call detection on atmospheric temperature and humidity. Height or distance from origin had the largest influence on call detection, while temperature and humidity also influenced detectability at higher altitudes. Because flight call detection varies with both atmospheric conditions and flight height, improved monitoring across time and space will require correction for these factors to generate standardized metrics of songbird migration.

  8. On the effects of constraining atmospheric circulation in a coupled atmosphere-ocean Arctic regional climate model

    NASA Astrophysics Data System (ADS)

    Berg, Peter; Döscher, Ralf; Koenigk, Torben

    2016-06-01

    Impacts of spectral nudging on simulations of Arctic climate in coupled simulations have been investigated in a set of simulations with a regional climate model (RCM). The dominantly circumpolar circulation in the Arctic lead to weak constraints on the lateral boundary conditions (LBCs) for the RCM, which causes large internal variability with strong deviations from the driving model. When coupled to an ocean and sea ice model, this results in sea ice concentrations that deviate from the observed spatial distribution. Here, a method of spectral nudging is applied to the atmospheric model RCA4 in order to assess the potentials for improving results for the sea ice concentrations when coupled to the RCO ocean-sea ice model. The spectral nudging applied to reanalysis driven simulations significantly improves the generated sea ice regarding its temporal evolution, extent and inter-annual trends, compared to simulations with standard LBC nesting. The method is furthermore evaluated with driving data from two CMIP5 GCM simulations for current and future conditions. The GCM biases are similar to the RCA4 biases with ERA-Interim, however, the spectral nudging still improves the surface winds enough to show improvements in the simulated sea ice. For both GCM downscalings, the spectrally nudged version retains a larger sea ice extent in September further into the future. Depending on the sea ice formulation in the GCM, the temporal evolution of the regional sea ice model can deviate strongly.

  9. The influence of processing atmosphere on twin-roll melt-spinning of aluminum alloys

    SciTech Connect

    Sellers, C.H.; Aldrich, K.S.; Cortez, M.M.; Wright, R.N.

    1992-09-01

    Melt-spun samples of Al-2%Fe have been produced in two different processing atmospheres, ambient pressure argon and a high vacuum. High speed video photography and microstructural analysis of the ribbons indicate that the processing pressure influences the interaction of the melt with the copper rolls and thus the thermal history. This results in significant differences in ribbon microstructure.

  10. Influence of atmospheric turbulence on optical measurement: a case report and review of literature

    NASA Astrophysics Data System (ADS)

    Yao, Linshen; Shang, Yang; Fu, Dan

    2016-01-01

    When videogammetry (optical measurement) was carried outdoor or under cruel indoor circumstance, the results would be inevitably affected by the atmosphere turbulence. As a result, the precision of surveying was destroyed. The field of air turbulence's impact on optical measurement was neglected by scholars for a long time, the achievements massed about laser optics and optical communications. The mostly adapted method was noise filtration when the pixel wandering could not be rejected in engineering application, which got little improvement on usual conditions. The principle of influence under atmospheric turbulence on optical measurement is presented in this paper. And experiments data and applications are carried out to announce the impact of atmospheric turbulence. Combining with relevant researches, some essential issues and expectations of the atmospheric turbulence research are proposed.

  11. The Influence of Atmospheric Conditions on the Production of Ozone during VOC Oxidation

    NASA Astrophysics Data System (ADS)

    Coates, J.; Butler, T. M.

    2015-12-01

    Tropospheric ozone is a short-lived climate forcing pollutant that is detrimental to human health and crop growth. Reactions involving volatile organic compounds (VOC) and nitrogen oxides (NOx) in the presence of sunlight produce ozone. Ozone production is a non-linear function of the concentrations of both NOx and VOC, with VOC acting as the "fuel" for ozone production and NOx as the "catalyst". Different VOC, due to their differing structure and carbon content, have different maximum potential to produce ozone. Due to different degrees of reactivity, VOC also differ in the time taken to reach this maximum ozone production potential under ideal conditions. Ozone production is also influenced by meteorological factors such as radiation, temperature, advection and mixing, which may alter the rate of ozone production, and the degree to which VOC are able to reach their maximum ozone production potential. Identifying the chemical and meteorological processes responsible for controlling the degree to which VOC are able to reach their maximum ozone production potential could inform decisions on emission control to efficiently tackle high levels of tropospheric ozone. In this study we use a boxmodel to determine the chemical processes affecting ozone production under different meteorological and chemical conditions. The chemistry scheme used by the boxmodel is "tagged" for each initial VOC enabling attribution of ozone production to its VOC source. We systematically vary a number of meteorological parameters along with the source of NOx within the box model to simulate a range of atmospheric conditions. These simulations are compared with a control simulation done under conditions of maximum ozone formation to determine which parameters affect the rate at which VOC produce ozone and the extent to which they reach their maximum potential to produce ozone. We perform multi-day simulations in order to examine whether these processes can influence ozone production over

  12. Regional US carbon sinks from three-dimensional atmospheric CO2 sampling.

    PubMed

    Crevoisier, Cyril; Sweeney, Colm; Gloor, Manuel; Sarmiento, Jorge L; Tans, Pieter P

    2010-10-26

    Studies diverge substantially on the actual magnitude of the North American carbon budget. This is due to the lack of appropriate data and also stems from the difficulty to properly model all the details of the flux distribution and transport inside the region of interest. To sidestep these difficulties, we use here a simple budgeting approach to estimate land-atmosphere fluxes across North America by balancing the inflow and outflow of CO(2) from the troposphere. We base our study on the unique sampling strategy of atmospheric CO(2) vertical profiles over North America from the National Oceanic and Atmospheric Administration/Earth System Research Laboratory aircraft network, from which we infer the three-dimensional CO(2) distribution over the continent. We find a moderate sink of 0.5 ± 0.4 PgC y(-1) for the period 2004-2006 for the coterminous United States, in good agreement with the forest-inventory-based estimate of the first North American State of the Carbon Cycle Report, and averaged climate conditions. We find that the highest uptake occurs in the Midwest and in the Southeast. This partitioning agrees with independent estimates of crop uptake in the Midwest, which proves to be a significant part of the US atmospheric sink, and of secondary forest regrowth in the Southeast. Provided that vertical profile measurements are continued, our study offers an independent means to link regional carbon uptake to climate drivers.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. The Influence of the Extreme Ultraviolet Spectral Energy Distribution on the Structure and Composition of the Upper Atmosphere of Exoplanets

    NASA Astrophysics Data System (ADS)

    Guo, J. H.; Ben-Jaffel, Lotfi

    2016-02-01

    By varying the profiles of stellar extreme ultraviolet (EUV) spectral energy distributions (SEDs), we tested the influences of stellar EUV SEDs on the physical and chemical properties of an escaping atmosphere. We apply our model to study four exoplanets: HD 189733b, HD 209458b, GJ 436b, and Kepler-11b. We find that the total mass loss rates of an exoplanet, which are determined mainly by the integrated fluxes, are moderately affected by the profiles of the EUV SED, but the composition and species distributions in the atmosphere can be dramatically modified by the different profiles of the EUV SED. For exoplanets with a high hydrodynamic escape parameter (λ), the amount of atomic hydrogen produced by photoionization at different altitudes can vary by one to two orders of magnitude with the variation of stellar EUV SEDs. The effect of photoionization of H is prominent when the EUV SED is dominated by the low-energy spectral region (400–900 Å), which pushes the transition of H/H+ to low altitudes. In contrast, the transition of H/H+ moves to higher altitudes when most photons are concentrated in the high-energy spectral region (50–400 Å). For exoplanets with a low λ, the lower temperatures of the atmosphere make many chemical reactions so important that photoionization alone can no longer determine the composition of the escaping atmosphere. For HD 189733b, it is possible to explain the time variability of Lyα between 2010 and 2011 by a change in the EUV SED of the host K-type star, yet invoking only thermal H i in the atmosphere.

  15. Characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge with array generators

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Bin; Nie, Qiu-Yue

    2015-09-01

    The two-dimensional spatially extended atmospheric plasma arrays by many parallel radio-frequency glow discharge plasma jets packed densely, represent a feature option of large-scale low-temperature atmospheric plasma technologies with distinct capability of directed delivery of reactive species and good insusceptibility to sample variations. However, it is still a challenge to form plasma jet with large area of uniform active species on a downstream substrate due to the complex interactions between individual jets. This paper proposes to numerically study the strategy and mechanism of control/modulation for the array discharge to produce two-dimensional plasma uniformity in the downstream working area. In this work, a two dimensional fluid model is employed to investigate the characteristics in the jet region of helium radio-frequency atmospheric-pressure glow discharge (RF APGD) with array generators. The influences of upstream discharge characteristics, gas flow and their cooperative effects on the distribution of species densities, gas temperatures and the uniformity of active species in the material treating area is studied, and the essential strategy for the modulation method is acquired. The results will be significant for deep understanding of coupling behaviors of multiple plasma plumes in the RF APGD array and applications of the technology.

  16. Constraining regional scale carbon budgets at the US West Coast using a high-resolution atmospheric inverse modeling approach

    NASA Astrophysics Data System (ADS)

    Goeckede, M.; Michalak, A. M.; Vickers, D.; Turner, D.; Law, B.

    2009-04-01

    The study presented is embedded within the NACP (North American Carbon Program) West Coast project ORCA2, which aims at determining the regional carbon balance of the US states Oregon, California and Washington. Our work specifically focuses on the effect of disturbance history and climate variability, aiming at improving our understanding of e.g. drought stress and stand age on carbon sources and sinks in complex terrain with fine-scale variability in land cover types. The ORCA2 atmospheric inverse modeling approach has been set up to capture flux variability on the regional scale at high temporal and spatial resolution. Atmospheric transport is simulated coupling the mesoscale model WRF (Weather Research and Forecast) with the STILT (Stochastic Time Inverted Lagrangian Transport) footprint model. This setup allows identifying sources and sinks that influence atmospheric observations with highly resolved mass transport fields and realistic turbulent mixing. Terrestrial biosphere carbon fluxes are simulated at spatial resolutions of up to 1km and subdaily timesteps, considering effects of ecoregion, land cover type and disturbance regime on the carbon budgets. Our approach assimilates high-precision atmospheric CO2 concentration measurements and eddy-covariance data from several sites throughout the model domain, as well as high-resolution remote sensing products (e.g. LandSat, MODIS) and interpolated surface meteorology (DayMet, SOGS, PRISM). We present top-down modeling results that have been optimized using Bayesian inversion, reflecting the information on regional scale carbon processes provided by the network of high-precision CO2 observations. We address the level of detail (e.g. spatial and temporal resolution) that can be resolved by top-down modeling on the regional scale, given the uncertainties introduced by various sources for model-data mismatch. Our results demonstrate the importance of accurate modeling of carbon-water coupling, with the

  17. Influence of the E region dynamo on equatorial spread F

    NASA Technical Reports Server (NTRS)

    Hanson, W. B.; Sanatani, S.; Patterson, T. N. L.

    1983-01-01

    The integrated E region Pedersen conductivity can be an important parameter in determining whether the bottomside of the equatorial F layer will be stable against the Rayleigh-Taylor gravitational instability. The F layer is observed to become unstable when it rises to great heights after sunset. One effect of this height rise is to decrease the stabilizing influence of ion-neutral collisions at F region heights. It is shown here that the same eastward electric field that raises the F layer also decreases the Pedersen conductivity of the E region, which further destabilizes convective overturning. Because the conductivity of magnetic tubes that penetrate the main F layer is large compared to the E layer contribution, these effects are important only for the bottomside of the equatorial F layer.

  18. [Concentration distribution of metal elements in atmospheric aerosol under different weather conditions in Qingdao Coastal Region].

    PubMed

    Chen, Xiao-Jing; Qi, Jian-Hua; Liu, Ning; Zhang, Xiang-Yu; Shen, Heng-Qing; Liu, Ming-Xu

    2014-10-01

    To know the influence of different weather conditions on the concentration of metal elements in aerosols in the coastal region, total suspended particles (TSP) samples were collected from April to May 2012, and August 2012 to March 2013 in the Qingdao coastal region, and common trace metals were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Al, Ca, Fe, Na, K and Mg were the dominant metal elements in TSP, and the sum of the six elements accounted for 94.2% of the sum of all metals. TSP and metal elements had significant monthly variations, Fe, Al, K, Ca, Mg, Zn, Ba, Mn, Ti, Sr and Li had the highest concentration in November and January, while Be, Sc, Co, Ni and Cr showed the highest value in January. Na had the highest concentration in August, November and February, and the lowest in December. Pb had the highest concentration in January and February, and the lowest in August and December. Enrichment factors indicated that Be, Co, Al, Ca, Fe, K, Mg, Mn, Sr and Ti were mainly affected by natural sources; Li, Cr, Ni, Zn, Ba and Na were affected by natural sources and part of anthropogenic sources; Pb was mainly from anthropogenic sources. Different weather conditions had great impact on TSP and metal elements concentrations, all the measured metals had the highest concentrations in smog except Ti. Compared with the sunny day, the concentration of atmospheric particulate Ti decreased, while the other elements increased by 1 to 4 times in smog. Li, Be, Cr, Ni, Al, Fe, Mg and Mn had little variation in concentration in foggy day, and the concentration of Pb and Na increased considerably. The concentration of Co, Ca and Ti reduced obviously in fog. Except for Cr, Co and Ti, the other elements increased by 1 to 3 times in haze. Most of the elements had the minimal enrichment factors in sunny day, while the other had the maximal enrichment factor in

  19. [Concentration distribution of metal elements in atmospheric aerosol under different weather conditions in Qingdao Coastal Region].

    PubMed

    Chen, Xiao-Jing; Qi, Jian-Hua; Liu, Ning; Zhang, Xiang-Yu; Shen, Heng-Qing; Liu, Ming-Xu

    2014-10-01

    To know the influence of different weather conditions on the concentration of metal elements in aerosols in the coastal region, total suspended particles (TSP) samples were collected from April to May 2012, and August 2012 to March 2013 in the Qingdao coastal region, and common trace metals were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Al, Ca, Fe, Na, K and Mg were the dominant metal elements in TSP, and the sum of the six elements accounted for 94.2% of the sum of all metals. TSP and metal elements had significant monthly variations, Fe, Al, K, Ca, Mg, Zn, Ba, Mn, Ti, Sr and Li had the highest concentration in November and January, while Be, Sc, Co, Ni and Cr showed the highest value in January. Na had the highest concentration in August, November and February, and the lowest in December. Pb had the highest concentration in January and February, and the lowest in August and December. Enrichment factors indicated that Be, Co, Al, Ca, Fe, K, Mg, Mn, Sr and Ti were mainly affected by natural sources; Li, Cr, Ni, Zn, Ba and Na were affected by natural sources and part of anthropogenic sources; Pb was mainly from anthropogenic sources. Different weather conditions had great impact on TSP and metal elements concentrations, all the measured metals had the highest concentrations in smog except Ti. Compared with the sunny day, the concentration of atmospheric particulate Ti decreased, while the other elements increased by 1 to 4 times in smog. Li, Be, Cr, Ni, Al, Fe, Mg and Mn had little variation in concentration in foggy day, and the concentration of Pb and Na increased considerably. The concentration of Co, Ca and Ti reduced obviously in fog. Except for Cr, Co and Ti, the other elements increased by 1 to 3 times in haze. Most of the elements had the minimal enrichment factors in sunny day, while the other had the maximal enrichment factor in

  20. Extensive release of methane from Arctic seabed west of Svalbard during summer 2014 does not influence the atmosphere

    NASA Astrophysics Data System (ADS)

    Myhre, C. Lund; Ferré, B.; Platt, S. M.; Silyakova, A.; Hermansen, O.; Allen, G.; Pisso, I.; Schmidbauer, N.; Stohl, A.; Pitt, J.; Jansson, P.; Greinert, J.; Percival, C.; Fjaeraa, A. M.; O'Shea, S. J.; Gallagher, M.; Le Breton, M.; Bower, K. N.; Bauguitte, S. J. B.; Dalsøren, S.; Vadakkepuliyambatta, S.; Fisher, R. E.; Nisbet, E. G.; Lowry, D.; Myhre, G.; Pyle, J. A.; Cain, M.; Mienert, J.

    2016-05-01

    We find that summer methane (CH4) release from seabed sediments west of Svalbard substantially increases CH4 concentrations in the ocean but has limited influence on the atmospheric CH4 levels. Our conclusion stems from complementary measurements at the seafloor, in the ocean, and in the atmosphere from land-based, ship and aircraft platforms during a summer campaign in 2014. We detected high concentrations of dissolved CH4 in the ocean above the seafloor with a sharp decrease above the pycnocline. Model approaches taking potential CH4 emissions from both dissolved and bubble-released CH4 from a larger region into account reveal a maximum flux compatible with the observed atmospheric CH4 mixing ratios of 2.4-3.8 nmol m-2 s-1. This is too low to have an impact on the atmospheric summer CH4 budget in the year 2014. Long-term ocean observatories may shed light on the complex variations of Arctic CH4 cycles throughout the year.

  1. Regional Variation and Trends in IASI-Observed Atmospheric Ammonia Concentrations over the United States

    NASA Astrophysics Data System (ADS)

    Schiferl, L. D.; Heald, C. L.; Van Damme, M.; Clerbaux, C.; Coheur, P.

    2013-12-01

    Quantifying atmospheric ammonia is a critical first step in investigating its role in the formation of fine particulate matter and ecosystem change. This study uses five years (2008-2012) of a new measurement of ammonia column concentrations derived from the Infrared Atmospheric Sounding Interferometer (IASI) instrument to explore ammonia levels in several regions (e.g. the Midwest, California, the Southeast) of the United States. These satellite measurements offer extensive daily coverage, providing a constraint on the evolution and spatial variation of ammonia across the United States. We identify observed ammonia variation between the regions in terms of both intra-annual (seasonal) change and trends throughout the entire time period. These variations are related to factors controlling ammonia emissions, chemistry and deposition, such as human and animal populations, farming practices, land use change and meteorological variables. These variations can also be used to drive Earth system model simulations of ammonia's effects on air quality, radiation balance and environmental degradation.

  2. Influence of positive slopes on ultrafast heating in an atmospheric nanosecond-pulsed plasma synthetic jet

    NASA Astrophysics Data System (ADS)

    Zhu, Yifei; Wu, Yun; Jia, Min; Liang, Hua; Li, Jun; Li, Yinghong

    2015-02-01

    The influence of positive slopes on the energy coupling and hydrodynamic responses in an atmospheric nanosecond-pulsed plasma synthetic jet (PSJ) was investigated using a validated dry air plasma kinetics model. Based on a 1D simulation of the energy transfer mechanism in ultrafast gas heating, and with reasonable simplification, a 2D model of a PSJ was developed to investigate the discharge characteristics and hydrodynamic responses under different rise times. In the 1D simulation, a shorter voltage rise time results in a higher electric field in less time, reduces the time of ionization front propagation and produces stronger ionization. The energy transfer efficiency of ultrafast heating is approximately 60% but a steeper positive slope could raise local heating power density and make input energy 77% higher at the cost of 2.4% lower energy transfer efficiency under the same voltage amplitude and pulse width. The quench heating power density is always 27-30 times higher than that of ion collision in most discharge regions, while ion collision heating power density is 10-103 times higher in the sheath region. In 2D PSJ simulation, spatial-temporal distribution of electron density, reduced electric field and deposited energy were calculated for the first time. Heating energy increases sharply with voltage rise time decrease in the time scale of 20-50 ns. Jet velocity increases by 100 m s-1 when the rise time is reduced by 20 ns. A shorter voltage rise time also leads to higher orifice pressure and temperature, but their peak values are limited by the structure of the orifice and the discharge cavity.

  3. Flood regionalization: A hybrid geographic and predictor-variable region-of-influence regression method

    USGS Publications Warehouse

    Eng, K.; Milly, P.C.D.; Tasker, Gary D.

    2007-01-01

    To facilitate estimation of streamflow characteristics at an ungauged site, hydrologists often define a region of influence containing gauged sites hydrologically similar to the estimation site. This region can be defined either in geographic space or in the space of the variables that are used to predict streamflow (predictor variables). These approaches are complementary, and a combination of the two may be superior to either. Here we propose a hybrid region-of-influence (HRoI) regression method that combines the two approaches. The new method was applied with streamflow records from 1,091 gauges in the southeastern United States to estimate the 50-year peak flow (Q50). The HRoI approach yielded lower root-mean-square estimation errors and produced fewer extreme errors than either the predictor-variable or geographic region-of-influence approaches. It is concluded, for Q50 in the study region, that similarity with respect to the basin characteristics considered (area, slope, and annual precipitation) is important, but incomplete, and that the consideration of geographic proximity of stations provides a useful surrogate for characteristics that are not included in the analysis. ?? 2007 ASCE.

  4. Assessment of dynamical downscaling in Japan using the Regional Atmospheric Modeling System (RAMS)

    NASA Astrophysics Data System (ADS)

    Dairaku, K.; Pielke, R. A.; Beltran-Przekurat, A. B.; Iizuka, S.; Sasaki, W.

    2009-12-01

    The responses of the climate system to increases in carbon dioxide concentrations and to changes in land use/land cover and the subsequent impacts of climatic variability on humans and natural ecosystems are of fundamental concern. Because regional responses of surface hydrological and biogeochemical changes are particularly complex, it is necessary to add spatial resolution to accurately assess critical interactions within the regional climate system for climate change impacts assessments. We quantified the confidence and the uncertainties of Type II dynamical downscaling which the lateral and bottom boundary conditions were obtained from Japanese 25-year ReAnalysis (JRA-25) and assessed the value (skill) added by the downscaling to a climate simulation in Japan. We investigated the reproducibility of present climate using two regional climate models with 20 km horizontal grid spacing, the atmosphere-biosphere-river coupling regional climate model (NIED-RAMS) and the Meteorological Research Institute Nonhydrostatic Model (MRI-NHM), both of which used JRA-25 as boundary conditions. Two key variables for impact studies, surface air temperature and precipitation, were compared with the Japanese high-resolution surface observation, Automated Meteorological Data Acquisition System (AMeDAS) on 78 river basins. Results simulated by the two models were relatively in good agreement with the observation on the basin scale. The NIED-RAMS bias of 2 m air temperature (2mT) were less than 0.5K and the bias of precipitation (P) were around 10% in most of the river basins on annual averages for three years (2002-2004). The biases over 29 years shown in the long term experiment are similar to those of the three year simulation. The model could add some information as to where the larger scale information was obtained. A regional climate model often has sensitivity to model configurations, such as domain size and nudging scheme. We conducted sensitivity experiments to domain size

  5. Snow-atmosphere coupling in current and future climates over North America in the Canadian Regional Climate Model (CRCM5)

    NASA Astrophysics Data System (ADS)

    Tefera Diro, Gulilat; Sushama, Laxmi

    2016-04-01

    The influence of snow variation on climate variability over North America is assessed using the fifth generation of Canadian Regional Climate Model (CRCM5). For this, we first carried out a suite of CRCM5 simulations driven by ERA-Interim reanalysis, whereby the snow was either prescribed (uncoupled) or allowed to evolve interactively (coupled) during the model integration. Results indicate a systematic influence of snow on the inter-annual variability of air and surface temperature throughout winter and spring seasons. In the coupled simulations, where the snow depth and snow cover were allowed to evolve freely, the inter-annual variability of surface and near surface air temperatures were found to be larger and explains up to 70% of the surface temperature variation over northern Great Plains and Canadian Prairies. The impact of snow is found to be stronger in spring than in winter, since in spring season both albedo and hydrological effects contribute to the variability in temperature. To study projected changes to snow-atmosphere coupling in future climate, coupled and uncoupled CRCM5 simulations, driven by coupled GCMs, were performed, for current (1981-2010) and future (2071-2100) climates. Coupling regions in the GCM-driven current climate simulations are similar to those obtained with ERA-Interim driven CRCM5 simulations discussed above. In future climate, snow-temperature coupling shows some change in spatial structures and in magnitudes. These results suggest that accurate initialization of snow condition could potentially be helpful to improve seasonal prediction skill over these snow-atmosphere coupling hotspot regions.

  6. Influence of stochastic sea ice parametrization on climate and the role of atmosphere-sea ice-ocean interaction.

    PubMed

    Juricke, Stephan; Jung, Thomas

    2014-06-28

    The influence of a stochastic sea ice strength parametrization on the mean climate is investigated in a coupled atmosphere-sea ice-ocean model. The results are compared with an uncoupled simulation with a prescribed atmosphere. It is found that the stochastic sea ice parametrization causes an effective weakening of the sea ice. In the uncoupled model this leads to an Arctic sea ice volume increase of about 10-20% after an accumulation period of approximately 20-30 years. In the coupled model, no such increase is found. Rather, the stochastic perturbations lead to a spatial redistribution of the Arctic sea ice thickness field. A mechanism involving a slightly negative atmospheric feedback is proposed that can explain the different responses in the coupled and uncoupled system. Changes in integrated Antarctic sea ice quantities caused by the stochastic parametrization are generally small, as memory is lost during the melting season because of an almost complete loss of sea ice. However, stochastic sea ice perturbations affect regional sea ice characteristics in the Southern Hemisphere, both in the uncoupled and coupled model. Remote impacts of the stochastic sea ice parametrization on the mean climate of non-polar regions were found to be small. PMID:24842027

  7. Influence of stochastic sea ice parametrization on climate and the role of atmosphere-sea ice-ocean interaction.

    PubMed

    Juricke, Stephan; Jung, Thomas

    2014-06-28

    The influence of a stochastic sea ice strength parametrization on the mean climate is investigated in a coupled atmosphere-sea ice-ocean model. The results are compared with an uncoupled simulation with a prescribed atmosphere. It is found that the stochastic sea ice parametrization causes an effective weakening of the sea ice. In the uncoupled model this leads to an Arctic sea ice volume increase of about 10-20% after an accumulation period of approximately 20-30 years. In the coupled model, no such increase is found. Rather, the stochastic perturbations lead to a spatial redistribution of the Arctic sea ice thickness field. A mechanism involving a slightly negative atmospheric feedback is proposed that can explain the different responses in the coupled and uncoupled system. Changes in integrated Antarctic sea ice quantities caused by the stochastic parametrization are generally small, as memory is lost during the melting season because of an almost complete loss of sea ice. However, stochastic sea ice perturbations affect regional sea ice characteristics in the Southern Hemisphere, both in the uncoupled and coupled model. Remote impacts of the stochastic sea ice parametrization on the mean climate of non-polar regions were found to be small.

  8. Procedures for the estimation of regional scale atmospheric emissions—An example from the North West Region of England

    NASA Astrophysics Data System (ADS)

    Lindley, S. J.; Longhurst, J. W. S.; Watson, A. F. R.; Conlan, D. E.

    This paper considers the value of applying an alternative pro rata methodology to the estimation of atmospheric emissions from a given regional or local area. Such investigations into less time and resource intensive means of providing estimates in comparison to traditional methods are important due to the potential role of new methods in the development of air quality management plans. A pro rata approach is used here to estimate emissions of SO 2, NO x, CO, CO 2, VOCs and black smoke from all sources and Pb from transportation for the North West region of England. This method has the advantage of using readily available data as well as being an easily repeatable procedure which provides a good indication of emissions to be expected from a particular geographical region. This can then provide the impetus for further emission studies and ultimately a regional/local air quality management plan. Results suggest that between 1987 and 1991 trends in the emissions of the pollutants considered have been less favourable in the North West region than in the nation as a whole.

  9. Influence of flowing helium gas on plasma plume formation in atmospheric pressure plasma

    SciTech Connect

    Yambe, Kiyoyuki; Konda, Kohmei; Ogura, Kazuo

    2015-05-15

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and a foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. The helium gas flowing out of quartz tube mixes with air, and the flow channel is composed of the regions of flowing helium gas and air. The plasma plume length is equivalent to the reachable distance of flowing helium gas. Although the amount of helium gas on the flow channel increases by increasing the inner diameter of quartz tube at the same gas flow velocity, the plasma plume length peaks at around 8 m/s of gas flow velocity, which is the result that a flow of helium gas is balanced with the amount of gas. The plasma plume is formed at the boundary region where the flow of helium gas is kept to the wall of the air.

  10. Regional emission and loss budgets of atmospheric methane (2002-2012)

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Patra, P. K.; Dlugokencky, E. J.; Ishijima, K.; Umezawa, T.; Ito, A.; Aoki, S.; Morimoto, S.; Kort, E. A.; Crotwell, A. M.; Ravi Kumar, K.; Nakazawa, T.

    2015-12-01

    Methane (CH4) plays important roles in atmospheric chemistry and short-term forcing of climate. Clear understanding of atmospheric CH4's budget of emissions and losses is required to aid sustainable development of Earth's future environment. We used an atmospheric chemistry-transport model (JAMSTEC's ACTM) for simulating atmospheric CH4. An inverse modeling system has been developed for estimating CH4 emissions (7 ensemble cases) from 53 land regions for 2002-2012 using measurements at 39 sites. Global net CH4 emissions varied between 505-509 and 524-545 Tg/yr during 2002-2004 and 2010-2012, respectively (ranges based on 6 inversion cases), with a step like increase in 2007 in agreement with atmospheric measurement. The inversion system did not account for interannual variations in radicals reacting with CH4 in atmosphere. Our results suggest that the recent update of EDGAR inventory (version 4.2FT2010) overestimated global total emissions by at least 25 Tg/yr in 2010. Increase in CH4 emission since 2004 originated in the tropical and southern hemisphere regions, with timing consistent with an increase of non-dairy cattle stocks by ~10% in 2012 from 1056 million heads in 2002, leading to ~10 Tg/yr increase in emissions from enteric fermentation. All 7 inversions robustly estimated the interannual variations in emissions, but poorly constrained the seasonal cycle amplitude or phase consistently for all regions due to sparse observational network. Forward simulation results using both the a priori and a posteriori emissions are compared with independent aircraft measurements for validation. By doing that we are able to reject the upper limit (545 Tg/yr) of global total emissions as 14 Tg/yr too high during 2008-2012, which allows us to further conclude that CH4 emission increase rate over the East Asia (China mainly) region was 7-8 Tg/yr between the 2002-2006 and 2008-2012 periods, contrary to 1-17 Tg/yr in the a priori emissions.

  11. The influence of an atmospheric Two-Way coupled model system on the predictability of extratropical cyclones

    NASA Astrophysics Data System (ADS)

    Schuster, Mareike; Thürkow, Markus; Weiher, Stefan; Kirchner, Ingo; Ulbrich, Uwe; Will, Andreas

    2016-04-01

    A general bias of global atmosphere ocean models, and also of the MPI-ESM, is an under-representation of the high latitude cyclone activity and an overestimation of the mid latitude cyclone activity in the North Atlantic, thus representing the extra-tropical storm track too zonal. We will show, that this effect can be antagonized by applying an atmospheric Two-Way Coupling (TWC). In this study we present a newly developed Two-Way Coupled model system, which is based on the MPI-ESM, and show that it is able to capture the mean storm track location more accurate. It also influences the sub-decadal deterministic predictability of extra-tropical cyclones and shows significantly enhanced skill compared to the "uncoupled" MPI-ESM standalone system. This study evaluates a set of hindcast experiments performed with said Two-Way Coupled model system. The regional model COSMO CLM is Two-Way Coupled to the atmosphere of the global Max-Plack-Institute Earth System Model (MPI-ESM) and therefore integrates and exchanges the state of the atmosphere every 10 minutes (MPI-TWC-ESM). In the coupled source region (North Atlantic), mesoscale processes which are relevant for the formation and early-stage development of cyclones are expected to be better represented, and therefore influence the large scale dynamics of the target region (Europe). The database covers 102 "uncoupled" years and 102 Two-Way Coupled years of the recent climate (1960-2010). Results are validated against the ERA-Interim reanalysis. Besides the climatological point of view, the design of this single model ensemble allows for an analysis of the predictability of the first and second leadyears of the hindcasts. As a first step to understand the improved predictability of cyclones, we will show a detailed analysis of climatologies for specific cyclone categories, sorted by season and region. Especially for cyclones affecting Europe, the TWC is capable to counteract the AOGCM's biases in the North Atlantic. Also

  12. On the simulation of allergenic pollen exposition and its atmospheric transport on regional scale

    NASA Astrophysics Data System (ADS)

    Biernath, Christian; Klein, Christian; Hoffmann, Peter; Gayler, Sebastian; Priesack, Eckart

    2013-04-01

    In Germany approximately 30% of the population is vulnerable to pollinosis (hay fever). Exposure to allergenic pollen affects vulnerable persons recurring seasonally, but depending on the individual susceptibility to individual pollen species. To prevent the suffering the patients usually use preventive drugs and rely on the current pollen forecast. However, recently used pollen forecast models mainly consider temperature sums to predict pollen exposition by different plant species. The models often fail to describe the impact of regionally variable environmental conditions on plant growth which depends on the soil characteristics that affect the water and nutrient availability. Furthermore, water and nutrient availability may significantly affect the pollen yield and its allergenic potential. Thus, the improvement of the simulations of the exposition of allergenic pollen by plants and atmospheric pollen loads on the regional scale could improve the preventive medication of vulnerable persons. We propose a new soil-plant-atmosphere model system that allows a dynamic ressource aquisition for the plant biomass growth to account for the allergenic potential of exposed pollen and the subsequent pollen transport in the atmosphere. Therefore, to simulate pollen exposure the land surface model Expert-N (soil-plant-system model) was coupled to the Weather Research and Forecast model (WRF). Expert-N uses site specific physical soil properties to simulate the nutrient and water transport, and the carbon and nitrogen turnover, as well as the interactions between plant and soil. The allergenic potential of pollen yield is simulated using a new C- and N-allocation model which accounts for the production of carbon-based secondary compounds (CBSCs). These CBSCs are involved in the determination of the allergenic potential of pollen. The WRF model is used to predict the weather conditions for plant growth. Depending on the weather conditions pollen exposed by the plants is then

  13. Climate change and climate systems influence and control the atmospheric dispersion of desert dust: implications for human health

    USGS Publications Warehouse

    Griffin, Dale W.; Ragaini, Richard C.

    2010-01-01

    The global dispersion of desert dust through Earth’s atmosphere is greatly influenced by temperature. Temporal analyses of ice core data have demonstrated that enhanced dust dispersion occurs during glacial events. This is due to an increase in ice cover, which results in an increase in drier terrestrial cover. A shorter temporal analysis of dust dispersion data over the last 40 years has demonstrated an increase in dust transport. Climate systems or events such as the North Atlantic Oscillation, the Indian Ocean subtropical High, Pacific Decadal Oscillation, and El Nino-Sothern Oscillation are known to influence global short-term dust dispersion occurrence and transport routes. Anthropogenic influences on dust transport include deforestation, harmful use of topsoil for agriculture as observed during the American Dust Bowl period, and the creation of dry seas (Aral Sea) and lakes (Lake Owens in California and Lake Chad in North Africa) through the diversion of source waters (for irrigation and drinking water supplies). Constituents of desert dust both from source regions (pathogenic microorganisms, organic and inorganic toxins) and those scavenged through atmospheric transport (i.e., industrial and agricultural emissions) are known to directly impact human and ecosystem health. This presentation will present a review of global scale dust storms and how these events can be both a detriment and benefit to various organisms in downwind environments.

  14. Simulating carbon exchange using a regional atmospheric model coupled to an advanced land-surface model

    NASA Astrophysics Data System (ADS)

    Ter Maat, H. W.; Hutjes, R. W. A.; Miglietta, F.; Gioli, B.; Bosveld, F. C.; Vermeulen, A. T.; Fritsch, H.

    2010-08-01

    This paper is a case study to investigate what the main controlling factors are that determine atmospheric carbon dioxide content for a region in the centre of The Netherlands. We use the Regional Atmospheric Modelling System (RAMS), coupled with a land surface scheme simulating carbon, heat and momentum fluxes (SWAPS-C), and including also submodels for urban and marine fluxes, which in principle should include the dominant mechanisms and should be able to capture the relevant dynamics of the system. To validate the model, observations are used that were taken during an intensive observational campaign in central Netherlands in summer 2002. These include flux-tower observations and aircraft observations of vertical profiles and spatial fluxes of various variables. The simulations performed with the coupled regional model (RAMS-SWAPS-C) are in good qualitative agreement with the observations. The station validation of the model demonstrates that the incoming shortwave radiation and surface fluxes of water and CO2 are well simulated. The comparison against aircraft data shows that the regional meteorology (i.e. wind, temperature) is captured well by the model. Comparing spatially explicitly simulated fluxes with aircraft observed fluxes we conclude that in general latent heat fluxes are underestimated by the model compared to the observations but that the latter exhibit large variability within all flights. Sensitivity experiments demonstrate the relevance of the urban emissions of carbon dioxide for the carbon balance in this particular region. The same tests also show the relation between uncertainties in surface fluxes and those in atmospheric concentrations.

  15. Atmospheric constraints on Plant Water Use Efficiency - drivers and regional patterns of change since 1900

    NASA Astrophysics Data System (ADS)

    Groenendijk, M.; Cox, P.; Lambert, F. H.; Booth, B.; Huntingford, C.

    2013-12-01

    Water Use Efficiency (WUE) defines the relationship between land-atmosphere water and carbon fluxes. With this simple mechanism, hydrological and carbon-cycle responses of vegetation to climate change can be more easily quantified. WUE increases with atmospheric carbon dioxide (CO2) concentration but also depends on changes in humidity and temperature. A positive CO2 fertilization effect can be locally constrained by humidity and temperature. By combining observed trends of these three climate variables over the 20th century regional trends in WUE can be calculated. The ecosystem WUEe is defined as a ratio of gross primary production and transpiration fluxes. On the leaf scale this is equal to the atmospheric WUEa, which is a function of the ambient and internal CO2 concentration, the saturated specific humidity (a function of temperature) and relative humidity. Using Fluxnet and CRU TS3.2 observations, and the JULES and HadCM3 models we explore the temporal and spatial variation of WUEe and WUEa, and how they respond to climate change. Leaf level definitions are valid at site level, where WUEe and WUEa simulated with JULES are equal and linearly increasing with atmospheric CO2 concentration for a range of sites. For drier sites lower values of both were simulated. The simulated values are within the same range as values derived from eddy covariance observations. Having shown the near equivalence between WUEe and WUEa for specific sites, we can use the formula for WUEa to estimate the change in global plant WUE over the 20th century, using observed climatological data and CO2 concentrations. The global average WUE increased by 25% since 1900, closely following the atmospheric CO2 concentration. But we identify large regional variation, with regions where WUE increased, but some significant regions where WUE has actually decreased during the last century. Here the CO2 fertilization effect is overtaken by an increasing offsetting temperature and related saturated

  16. Statistical study of emerging flux regions and the response of the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; Li, Hui

    2012-12-01

    We statistically study the properties of emerging flux regions (EFRs) and response of the upper solar atmosphere to the flux emergence using data from the Helioseismic and Magnetic Imager and the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. Parameters including total emerged flux, flux growth rate, maximum area, duration of the emergence and separation speed of the opposite polarities are adopted to delineate the properties of EFRs. The response of the upper atmosphere is addressed by the response of the atmosphere at different wavelengths (and thus at different temperatures). According to our results, the total emerged fluxes are in the range of (0.44-11.2)×1019 Mx while the maximum area ranges from 17 to 182 arcsec2. The durations of the emergence are between 1 and 12 h, which are positively correlated to both the total emerged flux and the maximum area. The maximum distances between the opposite polarities are 7-25 arcsec and are also positively correlated to the duration. The separation speeds are from 0.05 to 1.08 km s-1, negatively correlated to the duration. The derived flux growth rates are (0.1-1.3)×1019 Mx h-1, which are positively correlated to the total emerging flux. The upper atmosphere first responds to the flux emergence in the 1600Å chromospheric line, and then tens to hundreds of seconds later, in coronal lines, such as the 171Å (T = 105.8 K) and 211Å (T = 106.3 K) lines almost simultaneously, suggesting the successive heating of the atmosphere from the chromosphere to the corona.

  17. Precipitation recycling in West Africa - regional modeling, evaporation tagging and atmospheric water budget analysis

    NASA Astrophysics Data System (ADS)

    Arnault, Joel; Kunstmann, Harald; Knoche, Hans-Richard

    2015-04-01

    Many numerical studies have shown that the West African monsoon is highly sensitive to the state of the land surface. It is however questionable to which extend a local change of land surface properties would affect the local climate, especially with respect to precipitation. This issue is traditionally addressed with the concept of precipitation recycling, defined as the contribution of local surface evaporation to local precipitation. For this study the West African monsoon has been simulated with the Weather Research and Forecasting (WRF) model using explicit convection, for the domain (1°S-21°N, 18°W-14°E) at a spatial resolution of 10 km, for the period January-October 2013, and using ERA-Interim reanalyses as driving data. This WRF configuration has been selected for its ability to simulate monthly precipitation amounts and daily histograms close to TRMM (Tropical Rainfall Measuring Mission) data. In order to investigate precipitation recycling in this WRF simulation, surface evaporation tagging has been implemented in the WRF source code as well as the budget of total and tagged atmospheric water. Surface evaporation tagging consists in duplicating all water species and the respective prognostic equations in the source code. Then, tagged water species are set to zero at the lateral boundaries of the simulated domain (no inflow of tagged water vapor), and tagged surface evaporation is considered only in a specified region. All the source terms of the prognostic equations of total and tagged water species are finally saved in the outputs for the budget analysis. This allows quantifying the respective contribution of total and tagged atmospheric water to atmospheric precipitation processes. The WRF simulation with surface evaporation tagging and budgets has been conducted two times, first with a 100 km2 tagged region (11-12°N, 1-2°W), and second with a 1000 km2 tagged region (7-16°N, 6°W -3°E). In this presentation we will investigate hydro-atmospheric

  18. Improving Regional Forecast by Assimilating Atmospheric InfraRed Sounder (AIRS) Profiles into WRF Model

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and produce improved forecasts. One such source comes from the Atmospheric InfraRed Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. The purpose of this paper is to describe a procedure to optimally assimilate high resolution AIRS profile data into a regional configuration of the Advanced Research WRF (ARW) version 2.2 using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background type, and an optimal methodology for ingesting AIRS temperature and moisture profiles as separate overland and overwater retrievals with different error characteristics. The AIRS thermodynamic profiles are derived from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm and contain information about the quality of each temperature layer. The quality indicators were used to select the highest quality temperature and moisture data for each profile location and pressure level. The analyses were then used to conduct a month-long series of regional forecasts over the continental U.S. The long-term impacts of AIRS profiles on forecast were assessed against verifying NAM analyses and stage IV precipitation data.

  19. An Empirical Study of Atmospheric Correction Procedures for Regional Infrasound Amplitudes with Ground Truth.

    NASA Astrophysics Data System (ADS)

    Howard, J. E.

    2014-12-01

    This study focusses on improving methods of accounting for atmospheric effects on infrasound amplitudes observed on arrays at regional distances in the southwestern United States. Recordings at ranges of 150 to nearly 300 km from a repeating ground truth source of small HE explosions are used. The explosions range in actual weight from approximately 2000-4000 lbs. and are detonated year-round which provides signals for a wide range of atmospheric conditions. Three methods of correcting the observed amplitudes for atmospheric effects are investigated with the data set. The first corrects amplitudes for upper stratospheric wind as developed by Mutschlecner and Whitaker (1999) and uses the average wind speed between 45-55 km altitudes in the direction of propagation to derive an empirical correction formula. This approach was developed using large chemical and nuclear explosions and is tested with the smaller explosions for which shorter wavelengths cause the energy to be scattered by the smaller scale structure of the atmosphere. The second approach isa semi-empirical method using ray tracing to determine wind speed at ray turning heights where the wind estimates replace the wind values in the existing formula. Finally, parabolic equation (PE) modeling is used to predict the amplitudes at the arrays at 1 Hz. The PE amplitudes are compared to the observed amplitudes with a narrow band filter centered at 1 Hz. An analysis is performed of the conditions under which the empirical and semi-empirical methods fail and full wave methods must be used.

  20. Atmospheric Effects of Solar Energetic Particle Events In Magnetized and Non-Magnetized Regions of Mars

    NASA Astrophysics Data System (ADS)

    Jolitz, R.; Dong, C.; Lillis, R. J.; Curry, S.; Brain, D. A.; Larson, D. E.

    2015-12-01

    Solar and shock-accelerated heliospheric energetic charged particles represent an important if irregular source of energy to the Martian upper atmosphere. A Monte Carlo code has been developed to track a population of protons in an atmosphere and account for energy loss to collisional processes including heating, ionization, excitation, and charge transfer. The model framework is open to multiple planetary-specific inputs (e.g. three-dimensional neutral densities, electric and magnetic fields) and uses an adaptive trace algorithm to accurately model collisions in dense and sparse atmospheric regions. Applying 3-D models of electric and magnetic fields from the Michigan Mars MHD code and 1-D neutral densities from the Mars Global Thermosphere Ionosphere Model (M-GITM), we use this model to calculate volume rates of relevant proton-mediated energy loss processes in the Martian upper atmosphere. The model will be improved to generate ionization and heating rates in areas of strong and weak crustal magnetic fields for solar energetic particle events observed by the SEP instrument on MAVEN. Ultimately this will form part of a comprehensive model of solar wind interactions with Mars.

  1. Sensitivity of radiation absorbed in the ocean to atmospheric and oceanic parameters in the short wavelength region. I - Cloudless atmosphere

    NASA Astrophysics Data System (ADS)

    Masuda, Kazuhiko; Takashima, Tsutomu

    1988-08-01

    The effects of atmospheric and oceanic parameters on the measured shortwave radiation absorbed in the ocean and on the upward irradiance at the top of the atmosphere were investigated using a model atmosphere-ocean system under the conditions of cloudless atmosphere. The computations showed that, for theta(0) of about 45 deg, the absorbed radiation in the ocean depends mainly on the atmospheric turbidity. Precipitable water vapor and ozone in the atmosphere also affect the absorbed radiation, but they have little effect on the upward irradiance. The surface roughness and whitecaps have little effect on the absorbed radiation or the upward radiance if the surface wind speed is less than about 5 m/sec. Finally, the oceanic hydrosols have little effect on either of these characteristics except when they are of pure scattering type in a turbid condition.

  2. The Influence of Locally Increased Gravity Wave Drag on the Middle Atmosphere Circulation - A Model Study

    NASA Astrophysics Data System (ADS)

    Lilienthal, Friederike; Sacha, Petr; Jacobi, Christoph; Pisoft, Petr

    2016-04-01

    Internal gravity waves (GW) are one of the most dominant features in the middle atmosphere. They are a main contributor for energy and angular momentum transport and thus play an important role for atmospheric dynamics such as the Quasi Biennial Oscillation or the Brewer-Dobson circulation (BDC). GPS radio occultation measurements (e.g. Sacha et al., 2015) have shown that GW can appear in local hotspots, e.g. in the lower stratosphere of the Eastern Asia/North-western Pacific (EA/NP) region. Using these data as an input for the GW parameterization of a 3D primitive equation model for the middle and upper atmosphere (MUAM) we study the dynamical effects of such a localized breaking region. We further introduce an additional artificial GW drag in the lower stratosphere EA/NP region and show that a localized GW forcing is more efficient in creating planetary waves (PWs) than zonally uniform GW forcing. We observe PWs propagating both equatorward and poleward and upward along the edge of the polar vortex. Possible consequences for the polar vortex stability and stratosphere-troposphere exchange in the tropical region are discussed. Finally, applying 3D wave activity flux and 3D residual circulation diagnostics, we investigated the possible role of this area in the longitudinal variability of the BDC with a hypothesis of its enhanced downwelling branch in this region.

  3. Steep declines in atmospheric base cations in regions of Europe and North America

    NASA Astrophysics Data System (ADS)

    Hedin, Lars O.; Granat, Lennart; Likens, Gene E.; Adri Buishand, T.; Galloway, James N.; Butler, Thomas J.; Rodhe, Henning

    1994-01-01

    HUMAN activities have caused marked changes in atmospheric chemistry over large regions of Europe and North America. Although considerable attention has been paid to the effects of changes in the deposition of acid anions (such as sulphate and nitrate) on terrestrial and aquatic ecosystems1-7, little is known about whether the concentrations of basic components of the atmosphere have changed over time8,9 and what the biogeochemical consequences of such potential changes might be. In particular, there has been some controversy8-12 as to whether declines in base-cation deposition have countered effects of recent reductions in SO2emission. Here we report evidence for steep declines in the atmospheric concentrations of base cations (sum of non-sea-salt Ca2+, Mg2+, K+ and Na+) over the past 10 to 26 years from high-quality precipitation chemistry records in Europe and North America. To varying but generally significant degrees, these base-cation trends have offset recent reductions in sulphate deposition in the regions examined. The observed trends seem to be ecologically important on decadal timescales, and support earlier contentions8-10 that declines in the deposition of base cations may have contributed to increased sensitivity of poorly buffered ecosystems.

  4. Using regional-scale atmospheric δ13C of CO2 as an indicator of ecosystem health and function

    NASA Astrophysics Data System (ADS)

    Alden, C. B.; Miller, J. B.; White, J. W.; Yadav, V.; Michalak, A. M.

    2012-12-01

    optimized fluxes are interpreted at monthly and regional (~106 km2) scales. Influence functions (footprints) are generated with FLEXPART, driven by National Centers for Environmental Prediction Global Forecast System meteorology. Prior information is from CarbonTracker 2011 and SiB, and background CO2 and δ13C values are from NOAA/ESRL marine boundary layer and aircraft data. Quasi-daily atmospheric observations are from NOAA/ESRL Global Monitoring Division tall towers in Park Falls, Wisconsin; Argyle, Maine; Moody, Texas; West Branch, Iowa; and Beech Island, South Carolina. Weekly observations are from Environment Canada tall towers in Estevan Point, British Columbia; Sable Island, Nova Scotia; Fraserdale, Ontario; Churchill, Manitoba; and East Trout Lake, Saskatchewan. We will present optimized, monthly spatial fields of 13C plant discrimination for North America. By comparing these posterior results to the SiB prior, we will begin to evaluate potential shortcomings in SiB with regard to both C3/C4 distribution and conductance.

  5. The Influence of Atmospheric Aerosols on Air Quality Status of the Egyptian Nile Delta

    NASA Astrophysics Data System (ADS)

    El-Askary, H. M.; Zakey, A.

    2014-12-01

    Due to the combination of natural and anthropogenic sources of emission over the Nile Delta region, the air quality status is very poor and has a significant health hazards impacts on the population. Here we focused on the optical and chemical characterizations of atmospheric aerosols in the Nile Delta using the online integrated Environmental-Climate Aerosols model (EnvClimA) during a 10 year period 2000-2010. Observations from MODIS and SeaWiFS measurements supplemented by CALIPSO and some ground-based data from AERONET, are used to validate the EnvClimA model and to illustrate the aerosol characteristics and their sources. CALIPSO measurements were used to characterize the vertical structure of aerosols and their shapes (spherical and non-spherical) for major dust storms and biomass burning events. In this study we discussed the synoptic patterns and features, which are associated with either the dust storm or high pollution events. We used MODIS derived aerosol parameters to study seasonal changes in aerosol parameters due to the influence of dust storms, anthropogenic pollution and biomass (crop residue) burning. MODIS derived deep blue AOD provided better representation of aerosol loading over north Africa (Sahara region) along with dark-target AOD and related parameters. AERONET data provided aerosol optical depth, angstrom, fine mode fraction, size fraction, volume, effective radius, refractive index, single scattering albedo, and radiative forcing during different seasons dominated by dust storms, anthropogenic pollution and biomass burning (black cloud phenomena). The results indicated that the observed AOD decreases in the summer and increases again in the fall due to agricultural burning events. Ground-based AERONET data support the "Dark Product" MODIS retrievals, as they typically show a fall peak in the 500 nm region. The number of dust distribution frequencies over Egypt has more frequency in the southeast and northwest of Egypt (5-7.5 days

  6. The importance of atmospheric ammonia in the Rocky Mountain region of the western U.S

    NASA Astrophysics Data System (ADS)

    Collett, J. L.; Benedict, K. B.; Chen, D.; Day, D.; Prenni, A. J.; Li, Y.; Kreidenweis, S. M.; Schichtel, B. A.; McDade, C.; Malm, W. C.

    2013-12-01

    Although it is not a regulated pollutant, ammonia is an important contributor to several air quality problems. Included among these are the formation of fine particles that contribute to visibility degradation and adverse health effects as well as contributions to excess nitrogen deposition to sensitive ecosystems. Because it is not regulated, gaseous ammonia and fine particle ammonium have traditionally not been routinely measured in many air quality monitoring networks. Measurements of ammonium wet deposition by the National Atmospheric Deposition Program, however, clearly indicate an increasing contribution to reactive nitrogen deposition. Here we report observations of several recent research efforts to characterize atmospheric ammonia and ammonium in the Rocky Mountain region of the western United States. These include measurements made as part of the Rocky Mountain Atmospheric Nitrogen and Sulfur (RoMANS) deposition study (2006-10), the Grand Teton Reactive Nitrogen Deposition Study (GrandTReNDS) (2011), and through pilot-scale operation of an NHx (NHx = gaseous NH3 plus fine particle NH4+) monitoring effort at 9 sites within the Interagency Monitoring of PROtected Visual Environments (IMPROVE) program (2011-12). Measurements during RoMANS clearly reveal the importance of agricultural source emission contributions to both dry and wet reactive nitrogen deposition in Rocky Mountain National Park. The importance of ammonia and ammonium deposition is even greater at Grand Teton National Park, which often sits downwind of extensive agricultural operations in central Idaho and northern Utah. Over a year of measurements in the IMPROVE NHx pilot network reveals strong spatial gradients in reduced nitrogen concentrations across the Rocky Mountain region, with higher concentrations in regions closer to agricultural sources and at locations and times strongly impacted by wildfires. These observations, along with additional observations from other related studies in the

  7. LRO Lyman-Alpha Mapping Project (LAMP): Exploration of Permanently Shadowed Regions and the Lunar Atmosphere

    NASA Astrophysics Data System (ADS)

    Retherford, K. D.; Stern, S. A.; Black, R. K.; Slater, D. C.; Gladstone, G. R.; Feldman, P. D.; Crider, D. H.; Parker, J. W.; Dirks, G. J.; Versteeg, M. H.; Persson, K. B.; Sykes, H. A.; Davis, M. W.; Stack, J. A.; Case, T. R.; McCullough, L. D.; de Los Santos, A.; Kaufmann, D. E.; Andrews, P. M.

    2006-12-01

    LRO/LAMP is a UV spectrograph designed to address how water is formed on the moon, transported through the lunar atmosphere, and deposited in permanently shadowed regions (PSRs). Its main objectives are to 1) identify exposed water frost in PSRs, 2) characterize landforms and albedos in PSRs, 3) demonstrate the feasibility of using natural starlight and sky-glow illumination for future lunar surface mission applications, and 4) to assay the lunar atmosphere and its variability. The LAMP spectrograph will accomplish the first three objectives by measuring interplanetary HI Lyα sky-glow and FUV starlight reflected from the PSRs. Both of these light sources provide fairly uniform, but faint, illumination (e.g., the reflected Lyα signal is expected to be ~10~R). Thanks to LAMP's sensitivity, however, by the end of the nominal 1-year mission the SNR for a Lyα albedo map will be >100/km2 in the polar regions, allowing the characterization of subtle compositional and structural features. Dayside and nightside lunar surface reflectance measurements of other regions are also planned to measure variations in the illumination sources for improved accuracy. The production and transport of Lunar atmosphere constituents H and Ar will be investigated by observation of their resonantly scattered FUV emissions. The detection and discovery of other constituent emissions is also expected. LAMP albedo maps of PSR landforms and potential surface water ice will be used to identify landing sites for future scientific exploration of these regions and investigation of the intriguing processes that occur within them.

  8. Influence of 21st century atmospheric and sea surface temperature forcing on West African climate

    SciTech Connect

    Skinner, Chris B; Ashfaq, Moetasim; Diffenbaugh, Noah

    2011-01-01

    he persistence of extended drought events throughout West Africa during the 20th century has motivated a substantial effort to understand the mechanisms driving African climate variability, as well as the possible response to elevated greenhouse gas (GHG) forcing. We use an ensemble of global climate model experiments to examine the relative roles of future direct atmospheric radiative forcing and SST forcing in shaping potential future changes in boreal summer precipitation over West Africa. We find that projected increases in precipitation throughout the Western Sahel result primarily from direct atmospheric radiative forcing. The changes in atmospheric forcing generate a slight northward displacement and weakening of the African easterly jet (AEJ), a strengthening of westward monsoon flow onto West Africa and an intensification of the tropical easterly jet (TEJ). Alternatively, we find that the projected decreases in precipitation over much of the Guinea Coast region are caused by SST changes that are induced by the atmospheric radiative forcing. The changes in SSTs generate a weakening of the monsoon westerlies and the TEJ, as well as a decrease in low-level convergence and resultant rising air throughout the mid levels of the troposphere. Our experiments suggest a potential shift in the regional moisture balance of West Africa should global radiative forcing continue to increase, highlighting the importance of climate system feedbacks in shaping the response of regional-scale climate to global-scale changes in radiative forcing.

  9. Electric Currents and Fields in Middle and Low Atmosphere in Fair-Weather Regions due to Distant Thunderstorms

    NASA Astrophysics Data System (ADS)

    Velinov, Peter; Velinov, Peter; Tonev, Peter

    The electric currents created by the thunderstorms and the electrified shower clouds over the Earth flow into the global atmospheric electric circuit and are responsible for the formation in fair-weather regions of ionosphere-ground current of about 2 pA per square meter, as well as for the related fair-weather electric field of the order of 100 V/m at sea level. The link of the diurnal variations of the fair-weather electric field with the global thunderstorm activity has been widely studied with connection to the Wilson's hypothesis. To confirm this hypothesis directly, also the fair-weather electric field response to a strong single lightning discharge has being examined. Here we study theoretically the variations of the electric currents and fields in fair-weather regions at different altitudes of the lower and middle atmosphere, which are provoked by distant lightning discharges. The electric field variations can play an important role at higher altitudes (in the upper troposphere and above), where they are much larger and possibly influence the physical and chemical processes. For our goals we realize a globalscale model of the electric fields and currents generated by a lightning discharge, which is based on the Maxwell's equations. The fair-weather electric characteristics are studied by our model depending on the lightning parameters, location and distance. We also examine how variations of the conductivity in the strato/mesosphere due to changes of solar and geomagnetic activity affect the characteristics studied. Another question discussed is whether and how the mesospheric electric response to a remote lightning discharge is influenced by the conductivity anisotropy above 70 km and by the geomagnetic field geometry. The variations of the fairweather electric fields due to a distant lightning at tropospheric heights are also studied with respect to their presumable role in the cloud physics.

  10. The influence of large-scale atmospheric circulation on the variability of Barlad river streamflow

    NASA Astrophysics Data System (ADS)

    Chelcea, Silvia; Ionita, Monica

    2010-05-01

    The seasonal variability of Barlad river flow, situated in the eastern part of Romania, in connection with large-scale atmospheric circulation is analyzed for the period 1951-2005. The relationship with precipitation (PP) and temperature (TT) in the European sector, global sea surface temperature (SST), atmospheric circulation over the Northern Hemisphere and the moisture transport is investigated. Applying correlation and composite analyses, it has been found that the variability of winter flow is influenced by a North Atlantic Oscillation (NAO) like pattern. On seasonal time scale, high flow anomalies are strongly correlated with winter TT and PP anomalies over land. There is an out-of-phase relationship between Barlad flow and TT over Scandinavian region and an in-phase relationship with TT anomalies over the southern part of Europe. This pattern in the TT field is similar to the negative phase of the NAO. High anomalies of the river flow are associated with a tripole-like pattern in the North Atlantic and with negative SST anomalies in the central North Pacific and positive anomalies in the eastern and central tropical Pacific. Positive anomalies of winter streamflow are associated with positive anomalies of sea level pressure (SLP) and 500 hPa geopotential height (G500) centered over the northern part of Europe and Greenland and negative anomalies centred over the mid Atlantic Ocean and the southern part of Europe. Vector plots of the vertically integrated water vapour transport composites show that during years with low flow anomalies there is a significant reduction of the water vapour transport downstream southern Europe and a shift of the axis of the water vapour transport towards Scandinavia are. Low flow anomalies are also found in connection with an intense zone of divergence over the eastern part of Romania, where the catchement area of Balrad river is situated. Wavelet and cross spectra techniques are also used to identify the coherent cyclic and non

  11. Influence of Atmospheric Processes on the Solubility and Composition of Iron in Saharan Dust.

    PubMed

    Longo, Amelia F; Feng, Yan; Lai, Barry; Landing, William M; Shelley, Rachel U; Nenes, Athanasios; Mihalopoulos, Nikolaos; Violaki, Kalliopi; Ingall, Ellery D

    2016-07-01

    Aerosol iron was examined in Saharan dust plumes using a combination of iron near-edge X-ray absorption spectroscopy and wet-chemical techniques. Aerosol samples were collected at three sites located in the Mediterranean, the Atlantic, and Bermuda to characterize iron at different atmospheric transport lengths and time scales. Iron(III) oxides were a component of aerosols at all sampling sites and dominated the aerosol iron in Mediterranean samples. In Atlantic samples, iron(II and III) sulfate, iron(III) phosphate, and iron(II) silicates were also contributors to aerosol composition. With increased atmospheric transport time, iron(II) sulfates are found to become more abundant, aerosol iron oxidation state became more reduced, and aerosol acidity increased. Atmospheric processing including acidic reactions and photoreduction likely influence the form of iron minerals and oxidation state in Saharan dust aerosols and contribute to increases in aerosol-iron solubility. PMID:27286140

  12. Correlating CCM upper atmosphere parameters to surface observations for regional climate change predictions

    SciTech Connect

    Li, Xiangshang; Sailor, D.J.

    1997-11-01

    This paper explores the use of statistical downscaling of General Circulation Model (GCM) results for the purpose of regional climate change analysis. The strong correlation between surface observations and GCM upper air predictions is used in an approach very similar to the Model Output Statistics approach used in numerical weather prediction. The primary assumption in this analysis is that the statistical relationships remain unchanged under conditions of climatic change. These relations are applied to GCM upper atmosphere predictions for future (2*CO{sub 2}) climate predictions. The result is a set of regional climate change predictions conceptually valid at the scale of cities. The downscaling for specific cities within a GCM grid cell reveals some of the anticipated variability within the grid cell. In addition, multiple linear regression analysis may indicate warming that is significantly higher or lower for a particular region than the raw data from the GCM runs. 3 refs., 3 figs., 2 tabs.

  13. Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.

    PubMed

    Percival, Carl J; Welz, Oliver; Eskola, Arkke J; Savee, John D; Osborn, David L; Topping, David O; Lowe, Douglas; Utembe, Steven R; Bacak, Asan; McFiggans, Gordon; Cooke, Michael C; Xiao, Ping; Archibald, Alexander T; Jenkin, Michael E; Derwent, Richard G; Riipinen, Ilona; Mok, Daniel W K; Lee, Edmond P F; Dyke, John M; Taatjes, Craig A; Shallcross, Dudley E

    2013-01-01

    Carbonyl oxides ("Criegee intermediates"), formed in the ozonolysis of alkenes, are key species in tropospheric oxidation of organic molecules and their decomposition provides a non-photolytic source of OH in the atmosphere (Johnson and Marston, Chem. Soc. Rev., 2008, 37, 699, Harrison et al, Sci, Total Environ., 2006, 360, 5, Gäb et al., Nature, 1985, 316, 535, ref. 1-3). Recently it was shown that small Criegee intermediates, C.I.'s, react far more rapidly with SO2 than typically represented in tropospheric models, (Welz, Science, 2012, 335, 204, ref. 4) which suggested that carbonyl oxides could have a substantial influence on the atmospheric oxidation of SO2. Oxidation of 502 is the main atmospheric source of sulphuric acid (H2SO4), which is a critical contributor to aerosol formation, although questions remain about the fundamental nucleation mechanism (Sipilä et al., Science, 2010, 327, 1243, Metzger et al., Proc. Natl. Acad. Sci. U. S. A., 2010 107, 6646, Kirkby et al., Nature, 2011, 476, 429, ref. 5-7). Non-absorbing atmospheric aerosols, by scattering incoming solar radiation and acting as cloud condensation nuclei, have a cooling effect on climate (Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: The Physical Science Basis, Cambridge University Press, 2007, ref. 8). Here we explore the effect of the Criegees on atmospheric chemistry, and demonstrate that ozonolysis of alkenes via the reaction of Criegee intermediates potentially has a large impact on atmospheric sulphuric acid concentrations and consequently the first steps in aerosol production. Reactions of Criegee intermediates with SO2 will compete with and in places dominate over the reaction of OH with SO2 (the only other known gas-phase source of H2SO4) in many areas of the Earth's surface. In the case that the products of Criegee intermediate reactions predominantly result in H2SO4 formation, modelled particle nucleation rates can be substantially increased by the improved

  14. Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.

    PubMed

    Percival, Carl J; Welz, Oliver; Eskola, Arkke J; Savee, John D; Osborn, David L; Topping, David O; Lowe, Douglas; Utembe, Steven R; Bacak, Asan; McFiggans, Gordon; Cooke, Michael C; Xiao, Ping; Archibald, Alexander T; Jenkin, Michael E; Derwent, Richard G; Riipinen, Ilona; Mok, Daniel W K; Lee, Edmond P F; Dyke, John M; Taatjes, Craig A; Shallcross, Dudley E

    2013-01-01

    Carbonyl oxides ("Criegee intermediates"), formed in the ozonolysis of alkenes, are key species in tropospheric oxidation of organic molecules and their decomposition provides a non-photolytic source of OH in the atmosphere (Johnson and Marston, Chem. Soc. Rev., 2008, 37, 699, Harrison et al, Sci, Total Environ., 2006, 360, 5, Gäb et al., Nature, 1985, 316, 535, ref. 1-3). Recently it was shown that small Criegee intermediates, C.I.'s, react far more rapidly with SO2 than typically represented in tropospheric models, (Welz, Science, 2012, 335, 204, ref. 4) which suggested that carbonyl oxides could have a substantial influence on the atmospheric oxidation of SO2. Oxidation of 502 is the main atmospheric source of sulphuric acid (H2SO4), which is a critical contributor to aerosol formation, although questions remain about the fundamental nucleation mechanism (Sipilä et al., Science, 2010, 327, 1243, Metzger et al., Proc. Natl. Acad. Sci. U. S. A., 2010 107, 6646, Kirkby et al., Nature, 2011, 476, 429, ref. 5-7). Non-absorbing atmospheric aerosols, by scattering incoming solar radiation and acting as cloud condensation nuclei, have a cooling effect on climate (Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: The Physical Science Basis, Cambridge University Press, 2007, ref. 8). Here we explore the effect of the Criegees on atmospheric chemistry, and demonstrate that ozonolysis of alkenes via the reaction of Criegee intermediates potentially has a large impact on atmospheric sulphuric acid concentrations and consequently the first steps in aerosol production. Reactions of Criegee intermediates with SO2 will compete with and in places dominate over the reaction of OH with SO2 (the only other known gas-phase source of H2SO4) in many areas of the Earth's surface. In the case that the products of Criegee intermediate reactions predominantly result in H2SO4 formation, modelled particle nucleation rates can be substantially increased by the improved

  15. An overview of the regional experiments for land-atmosphere exchanges 2012 (REFLEX 2012) campaign

    NASA Astrophysics Data System (ADS)

    Timmermans, Wim; Van der Tol, Christiaan; Timmermans, Joris; Ucer, Murat; Chen, Xuelong; Alonso, Luis; Moreno, Jose; Carrara, Arnaud; Lopez, Ramon; de la Cruz Tercero, Fernando; Corcoles, Horacio L.; de Miguel, Eduardo; Sanchez, Jose A. G.; Pérez, Irene; Franch, Belen; Munoz, Juan-Carlos J.; Skokovic, Drazen; Sobrino, Jose; Soria, Guillem; MacArthur, Alasdair; Vescovo, Loris; Reusen, Ils; Andreu, Ana; Burkart, Andreas; Cilia, Chiara; Contreras, Sergio; Corbari, Chiara; Calleja, Javier F.; Guzinski, Radoslaw; Hellmann, Christine; Herrmann, Ittai; Kerr, Gregoire; Lazar, Adina-Laura; Leutner, Benjamin; Mendiguren, Gorka; Nasilowska, Sylwia; Nieto, Hector; Pachego-Labrador, Javier; Pulanekar, Survana; Raj, Rahul; Schikling, Anke; Siegmann, Bastian; von Bueren, Stefanie; Su, Zhongbo (Bob)

    2014-12-01

    The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.

  16. Atmospheric CO2 Inversions of the Mid-Continental Intensive (MCI) Region (Invited)

    NASA Astrophysics Data System (ADS)

    Schuh, A. E.; Denning, A.; Ogle, S. M.; Corbin, K.; Uliasz, M.; Davis, K. J.; Lauvaux, T.; Miles, N.; Andrews, A. E.; Petron, G.; Huntzinger, D. N.

    2009-12-01

    We combine the SiB3 biosphere model with the RAMS mesoscale meteorology model and associated Lagrangian particle dispersion model (LPDM) and use CO2 observations from an extensive tower network in 2007 to correct a priori ecosystem respiration (ER) and gross primary productivity (GPP) fluxes for a domain consisting of most of North America. In particular, eight of these towers are located in a concentrated ring around the Mid-Continent Intensive (MCI) region of the United States providing one of the densest tower networks (CO2) in the world, in the midst of one of the strongest areas of seasonal carbon flux in the world. The unique area combined with dense observations and relatively simple atmospheric transport provides an incredible test-bed to investigate atmospheric CO2 inversions. Multiple inversion approaches are compared and contrasted. The results are then investigated for sensitivity to a priori inversion designs, boundary inflow contributions, and network density.

  17. An Overview of the Regional Experiments for Land-Atmosphere Exchanges 2012 (Reflex 2012) Campaign

    NASA Astrophysics Data System (ADS)

    Timmermans, Wim J.; Tol, Christiaan van der; Timmermans, Joris; Ucer, Murat; Chen, Xuelong; Alonso, Luis; Moreno, Jose; Carrara, Arnaud; Lopez, Ramon; de la Cruz Tercero, Fernando; Corcoles, Horacio L.; De Miguel, Eduardo; Sanchez, Jose A. G.; Pérez, Irene; Franch, Belen; Munoz, Juan-Carlos J.; Skokovic, Drazen; Sobrino, Jose; Soria, Guillem; MacArthur, Alasdair; Vescovo, Loris; Reusen, Ils; Andreu, Ana; Burkart, Andreas; Cilia, Chiara; Contreras, Sergio; Corbari, Chiara; Calleja, Javier F.; Guzinski, Radoslaw; Hellmann, Christine; Herrmann, Ittai; Kerr, Gregoire; Lazar, Adina-Laura; Leutner, Benjamin; Mendiguren, Gorka; Nasilowska, Sylwia; Nieto, Hector; Pachego-Labrador, Javier; Pulanekar, Survana; Raj, Rahul; Schikling, Anke; Siegmann, Bastian; von Bueren, Stefanie; Su, Zhongbo

    2015-12-01

    The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.

  18. A regional atmospheric fate and transport model for atrazine. 1. Development and implementation.

    PubMed

    Cooter, Ellen J; Hutzell, William T

    2002-10-01

    The Community Multiscale Air Quality (CMAQ) modeling system is adapted to simulate the regional transport and fate of atrazine, one of the most widely used herbicides in the United States. Model chemistry and deposition are modified, and a gas-to-particle partitioning algorithm is added to accommodate semivolatile behavior. The partitioning algorithm depends on humidity, temperature, and particulate matter concentration and composition. Results indicate that gaseous atrazine will usually dominate warm season atmospheric concentrations, but particulate form can surpass gas forms when atmospheric humidity is high (> 70%) and less-acidic (pH > 2.5) aqueous aerosol component is present. Implementation of the modified CMAQ for atrazine is illustrated, and, within the limits of our current understanding, preliminary transport and fate patterns appear to be reasonable. This research represents one of the first attempts to include a gas-to-particulate matter partitioning mechanism in an Eulerian grid-model.

  19. A study of the atmospheric stability and stability classifying schemes in the coastal region

    SciTech Connect

    Shaojia Fan; Ruoyu Bao; Xiaofen Luo; Jingguan Luo

    1996-12-31

    The atmospheric stability and its classifying schemes in terms of the Pasquill A-F classes have been analyzed by using the data obtained from a 100m tower located in the coastal area of Guangdong Province, China. Wind and temperature sensors were mounted on the tower at 10, 25, 50, 75, 100m levels respectively. Radiation sensors were mounted only at the ground level. Hourly averaged values of total radiation, net radiation, wind speed and standard deviation of horizontal wind direction, as well as temperature and vertical temperature difference were obtained over the period from December 1, 1992 to November 30, 1993. The results indicate that the atmospheric stability in the coastal region should be considered in terms of ground level stability (GS), vertical stability (VS) and horizontal stability (HS). The GS can be determined by the Pasquill-Turner method, the VS determined by the temperature lapse-rate and the HS determined by the - method.

  20. Earth-atmosphere system and surface reflectivities in arid regions from LANDSAT multispectral scanner measurements

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Fraser, R. S.

    1976-01-01

    Programs for computing atmospheric transmission and scattering solar radiation were used to compute the ratios of the Earth-atmosphere system (space) directional reflectivities in the vertical direction to the surface reflectivity, for the four bands of the LANDSAT multispectral scanner (MSS). These ratios are presented as graphs for two water vapor levels, as a function of the surface reflectivity, for various sun elevation angles. Space directional reflectivities in the vertical direction are reported for selected arid regions in Asia, Africa and Central America from the spectral radiance levels measured by the LANDSAT MSS. From these space reflectivities, surface vertical reflectivities were computed applying the pertinent graphs. These surface reflectivities were used to estimate the surface albedo for the entire solar spectrum. The estimated albedos are in the range 0.34-0.52, higher than the values reported by most previous researchers from space measurements, but are consistent with laboratory measurements.

  1. The influence of several changes in atmospheric states over semi-arid areas on the incidence of mental health disorders

    NASA Astrophysics Data System (ADS)

    Yackerson, Naomy S.; Zilberman, Arkadi; Todder, Doron; Kaplan, Zeev

    2011-05-01

    The incidence of suicide attempts [Deliberate Self Harm (DSH); ICD-10: X60-X84] and psychotic attacks (PsA; ICD-10, F20-F29) in association with atmospheric states, typical for areas close to big deserts, was analyzed. A retrospective study is based on the 4,325 cases of DSH and PsA registered in the Mental Health Center (MHC) of Ben-Gurion University (Be'er-Sheva, Israel) during 2001-2003. Pearson and Spearman test correlations were used; the statistical significance was tested at p < 0.1. The influence of temperature and humidity on suicide attempts ( N SU ) and psychotic attacks ( N PS ) was weakly pronounced ( p > 0.1). Correlation coefficients between N SU and N PS and speed WS of westerly wind reaches 0.3 ( p < 0.05), while their dependence on easterly WS was weaker ( p > 0.09). Variations in easterly wind direction WD influence N SU and N PS values ( p < 0.04), but no corresponding correlation with westerly winds was found ( p > 0.3). Obviously ,in transition areas located between different regions ,the main role of air streams in meteorological-biological impact can scarcely be exaggerated. An unstable balance in the internal state of a weather-sensitive person is disturbed when the atmospheric state is changed by specific desert winds, which can provoke significant perturbations in meteorological parameters. Results indicate the importance of wind direction, defining mainly the atmospheric situation in semi-arid areas: changes in direction of the easterly wind influence N SU and N PS , while changes in WS are important for mental health under westerly air streams. Obviously, N SU and N PS are more affected by the disturbance of weather from its normal state, for a given season, to which the local population is accustomed, than by absolute values of meteorological parameters.

  2. Identification of atmospheric mercury sources and transport pathways on local and regional sales

    NASA Astrophysics Data System (ADS)

    Gratz, Lynne E.

    Mercury (Hg) is a hazardous air pollutant and bioaccumulative neurotoxin whose intricate atmospheric chemistry complicates our ability to define Hg source-receptor relationships on all scales. Our detailed measurements of Hg in its different forms together with atmospheric tracers have improved our understanding of Hg chemistry and transport. Daily-event precipitation samples collected from 1995 to 2006 in Underhill, VT were examined to identify Hg wet deposition trends and source influences. Analysis revealed that annual Hg deposition at this fairly remote location did not vary significantly over the 12-year period. While a decreasing trend in volume-weighted mean Hg concentration was observed, Hg wet deposition did not decline as transport of emissions from the Midwest and along the Atlantic Coast consistently contributed to the largest observed Hg wet deposition events. Receptor modeling of Hg and trace elements in precipitation indicated that ---60% of Hg wet deposition at Underhill could be attributed to emissions from coal-fired utility boilers (CFUBs), and their contribution to Hg wet deposition did not change significantly over time. Hybrid-receptor modeling further defined these CFUBs to be located predominantly in the Midwestern U.S. Atmospheric Hg chemistry and transport from the Chicago urban/industrial area was the focus of speciated Hg measurements performed in the southern Lake Michigan basin during summer 2007. Transport from Chicago, IL to Holland, MI occurred during 27% of the study period, resulting in a five-fold increase in divalent reactive gaseous Hg (RGM) at the downwind Holland site. Dispersion modeling of case study periods demonstrated that under southwesterly flow approximately half of the RGM in Holland could be attributed to primary RGM emissions from Chicago after transport and dispersion, with the remainder due to Hg0 oxidation in the atmosphere en route. Precipitation and ambient vapor phase samples were also collected in Chicago

  3. Atmospheric chemistry in the Arctic and subarctic: Influence of natural fires, industrial emissions, and stratospheric inputs

    NASA Astrophysics Data System (ADS)

    Wofsy, S. C.; Sachse, G. W.; Gregory, G. L.; Blake, D. R.; Bradshaw, J. D.; Sandholm, S. T.; Singh, H. B.; Barrick, J. A.; Harriss, R. C.; Talbot, R. W.; Shipham, M. A.; Browell, E. V.; Jacob, D. J.; Logan, J. A.

    1992-10-01

    Haze layers with perturbed concentrations of trace gases, believed to originate from tundra and forest wild fires, were observed over extensive areas of Alaska and Canada in 1988. Enhancements of CH4, C2H2, C2H6, C3H8, and C4H10 were linearly correlated with CO in haze layers, with mean ratios (mole hydrocarbon/mole CO) of 0.18 (± 0.04 (1 σ)), 0.0019 (± 0.0001), 0.0055 (± 0.0002), 0.0008 (± 0.0001), and 1.2 × 10-4 (±0.2× 10-4), respectively. Enhancements of NOy, were variable, averaging 0.0056 (± 0.0030) mole NOy/mole CO, while perturbations of NOx were very small, usually undetectable. At least 1/3 of the NOy in the haze layers had been converted to peroxyacetyl nitrate (PAN), representing a potential source of NOx to the global atmosphere; much of the balance was oxidized to nitrate (HNO3 and paniculate). The composition of sub-Arctic haze layers was consistent with aged emissions from smoldering combustion, except for CH4, which appears to be partly biogenic. Inputs from the stratosphere and from biomass fires contributed major fractions of the NOy in the remote sub-Arctic troposphere. Analysis of aircraft and ground data indicates relatively little influence from mid-latitude industrial NOy in this region during summer, possibly excepting transport of PAN. Production of O3 was inefficient in sub-Arctic haze layers, less than 0.1 O3 molecules per molecule of CO, reflecting the low NOx/CO emission ratios from smoldering combustion. Mid-latitude pollution produced much more O3, 0.3 - 0.5 O3 molecules per molecule of CO, a consequence of higher NOx/CO emission ratios.

  4. Statistical analysis of the MODIS atmosphere products for the Tomsk region

    NASA Astrophysics Data System (ADS)

    Afonin, Sergey V.; Belov, Vladimir V.; Engel, Marina V.

    2005-10-01

    The paper presents the results of using the MODIS Atmosphere Products satellite information to study the atmospheric characteristics (the aerosol and water vapor) in the Tomsk Region (56-61°N, 75-90°E) in 2001-2004. The satellite data were received from the NASA Goddard Distributed Active Archive Center (DAAC) through the INTERNET.To use satellite data for a solution of scientific and applied problems, it is very important to know their accuracy. Despite the results of validation of the MODIS data have already been available in the literature, we decided to carry out additional investigations for the Tomsk Region. The paper presents the results of validation of the aerosol optical thickness (AOT) and total column precipitable water (TCPW), which are in good agreement with the test data. The statistical analysis revealed some interesting facts. Thus, for example, analyzing the data on the spatial distribution of the average seasonal values of AOT or TCPW for 2001-2003 in the Tomsk Region, we established that instead of the expected spatial homogeneity of these distributions, they have similar spatial structures.

  5. Human and natural influences on the changing thermal structure of the atmosphere.

    PubMed

    Santer, Benjamin D; Painter, Jeffrey F; Bonfils, Céline; Mears, Carl A; Solomon, Susan; Wigley, Tom M L; Gleckler, Peter J; Schmidt, Gavin A; Doutriaux, Charles; Gillett, Nathan P; Taylor, Karl E; Thorne, Peter W; Wentz, Frank J

    2013-10-22

    Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human-caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multimodel archive and multiple observational datasets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present evidence that a human-caused signal can also be identified relative to the larger "total" natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.

  6. Human and natural influences on the changing thermal structure of the atmosphere

    PubMed Central

    Santer, Benjamin D.; Painter, Jeffrey F.; Bonfils, Céline; Mears, Carl A.; Solomon, Susan; Wigley, Tom M. L.; Gleckler, Peter J.; Schmidt, Gavin A.; Doutriaux, Charles; Gillett, Nathan P.; Taylor, Karl E.; Thorne, Peter W.; Wentz, Frank J.

    2013-01-01

    Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multidecadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human-caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multimodel archive and multiple observational datasets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present evidence that a human-caused signal can also be identified relative to the larger “total” natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere. PMID:24043789

  7. Human and Natural Influences on the Changing Thermal Structure of the Atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    Santer, B. D.; Painter, J.; Bonfils, C.; Mears, C. A.; Solomon, S.; Wigley, T. M.; Gleckler, P. J.; Schmidt, G. A.; Doutriaux, C.; Gillett, N. P.; Taylor, K. E.; Thorne, P.; Wentz, F. J.

    2013-12-01

    Since the late 1970s, satellite-based instruments have monitored global changes in atmospheric temperature. These measurements reveal multi-decadal tropospheric warming and stratospheric cooling, punctuated by short-term volcanic signals of reverse sign. Similar long- and short-term temperature signals occur in model simulations driven by human- caused changes in atmospheric composition and natural variations in volcanic aerosols. Most previous comparisons of modeled and observed atmospheric temperature changes have used results from individual models and individual observational records. In contrast, we rely on a large multi-model archive and multiple observational data sets. We show that a human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations. Virtually all previous research in this area has attempted to discriminate an anthropogenic signal from internal variability. Here, we present the first evidence that a human-caused signal can also be identified relative to the larger "total" natural variability arising from sources internal to the climate system, solar irradiance changes, and volcanic forcing. Consistent signal identification occurs because both internal and total natural variability (as simulated by state-of-the-art models) cannot produce sustained global-scale tropospheric warming and stratospheric cooling. Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.

  8. Influences of characteristic meteorological conditions on atmospheric carbonyls in Beijing, China

    NASA Astrophysics Data System (ADS)

    Pang, Xiaobing; Mu, Yujing; Lee, Xinqing; Zhang, Yujie; Xu, Zhu

    2009-08-01

    Atmospheric pollutants are controlled not only by their production rates but also by meteorological conditions. The influences of dust storm, sauna weather (haze with high temperature and high humidity), wet precipitation and wind speed on atmospheric carbonyls in Beijing were investigated. During a severe dust episode (April 17, 2006), the mixing ratios of carbonyls were significantly elevated to 13-27 ppbV from 7 to 13 ppbV in the previous non-dust days (April 15 and 16) with the increasing extents of 38-154%. The accumulating effect and the lower photolysis rate in the dust day may be responsible for the increases of carbonyls' levels. Additionally, the contribution from heterogeneous reactions occurring on dust particles to formaldehyde and acetaldehyde cannot be ruled out. During the period of typical sauna weather, the concentrations of atmospheric carbonyls increased to 18-60 ppbV from 10 to 17 ppbV before the sauna days. The air mass over Beijing during the sauna days was controlled by a subtropical anticyclone and the boundary layer became quite stable, which was beneficial to the rapid accumulation of air pollutants including carbonyls. Wet precipitation was found to be an effective removal process to the atmospheric carbonyls. After one-hour of rain in summer, the total concentrations of atmospheric carbonyls decreased to less than half of that before the rainfall. The similar temporal varying patterns of carbonyls and inorganic ions in rainwater indicated that carbonyls were mainly washed out from the atmosphere into rainwater as inorganic ions were. Strong wind could evidently dilute atmospheric carbonyls and a negative correlation was found between wind speeds and the concentrations of carbonyls in spring in Beijing.

  9. Influence of ab initio chemistry models on simulations of the Ionian atmosphere

    NASA Astrophysics Data System (ADS)

    Parsons, Neal; Levin, Deborah A.; Walker, Andrew C.; Moore, Chris H.; Goldstein, David B.; Varghese, Philip L.; Trafton, Laurence

    2014-09-01

    There is significant scientific interest in simulating the unique atmospheric conditions on the Jovian moon Io that range from cold surface temperatures to hyperthermal interactions which possibly supply the Jovian plasma torus. The Direct Simulation Monte Carlo (DSMC) method is well suited to model the rarefied, predominantly SO2, Ionian atmosphere. High speed collisions between SO2 and the hypervelocity O atoms and ions that compose the plasma torus are a significant mechanism in determining the composition of the atmosphere; therefore, high-fidelity modeling of their interactions is crucial to the accuracy of such simulations. Typically, the Total Collision Energy (TCE) model is used to determine molecular dissociation probabilities and the Variable Hard Sphere (VHS) model is used to determine collision cross sections. However, the parameters for each of these baseline models are based on low-temperature experimental data and thus have unknown reliability for the hyperthermal conditions in the Ionian atmosphere. Recently, Molecular Dynamics/Quasi-Classical Trajectory (MD/QCT) studies have been conducted to generate accurate collision and chemistry models for the SO2-O collision pair in order to replace the baseline models. However, the influence of MD/QCT models on Ionian simulations compared to the previously used models is not well understood. In this work, 1D simulations are conducted using both the MD/QCT-based and baseline models in order to determine the effect of MD/QCT models on Ionian simulations. It is found that atmospheric structure predictions are highly sensitive to the chemistry and collision models. Specifically, the MD/QCT model predicts approximately half the SO2 atmospheric dissociation due to O and O+ bombardment compared to TCE models, and also predicts a temperature rise due to plasma heating further from the Ionian surface than the existing baseline methodologies. These findings indicate that the accurate MD/QCT chemistry and collision

  10. 21st century Mediterranean sea level rise: Steric and atmospheric pressure contributions from a regional model

    NASA Astrophysics Data System (ADS)

    Tsimplis, Michael N.; Marcos, Marta; Somot, Samuel

    2008-09-01

    An Atmosphere-Ocean Regional Climate Model coupled over the Mediterranean basin and forced by river runoff and influxes from the Atlantic Ocean and the Black Sea is used to obtain estimates of sea level rise in the region during the 21st century. Changes in temperature and salinity under the A2 emission scenario, which corresponds to a high level of anthropogenic gas concentration in the atmosphere, are investigated in the different sub-basins and are used to compute the steric sea level change in the region. Significant spatial variability is observed. This model projects a maximum steric sea level rise of 25 cm. The mean steric sea level rise value predicted is around 13 cm with lower values in the eastern Mediterranean and higher values at the western Mediterranean. Coastal sea level rise values are found to be smaller, although this is partly due to the smaller range of vertical integration in the computation of sea level changes. Warming and salinification of the intermediate waters are also predicted to occur simultaneously thus partly compensating each other. The effects of atmospheric pressure changes are added to the steric sea level obtained from the model giving up to 2 mbars and thus also compensating some of the thermal expansion. Circulation changes will in certain areas also add up to 6 cm of sea level rise. There is no predicted seasonal bias in the sea level rise indicating that the seasonal cycles will remain unaffected. These results are derived from a single model and therefore can only been seen as part of a methodological study. Similar investigations should be applied to a range of models and scenarios in order to obtain a range of the future sea level change in the Mediterranean basin and its associated uncertainties.

  11. Coupling of a regional atmospheric model (RegCM3) and a regional oceanic model (FVCOM) over the maritime continent

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Malanotte-Rizzoli, Paola; Eltahir, Elfatih A. B.; Xue, Pengfei; Xu, Danya

    2014-09-01

    Climatological high resolution coupled climate model simulations for the maritime continent have been carried out using the regional climate model (RegCM) version 3 and the finite volume coastal ocean model (FVCOM) specifically designed to resolve regions characterized by complex geometry and bathymetry. The RegCM3 boundary forcing is provided by the EMCWF-ERA40 re-analysis. FVCOM is embedded in the Global MITgcm which provides boundary forcing. The domain of the coupled regional model covers the entire South China Sea with its through-flow, the entire Indonesian archipelago with the Indonesian through-flow (ITF) and includes a large region in the western Pacific and eastern Indian oceans. The coupled model is able to provide stable and realistic climatological simulations for a specific decade of atmospheric-oceanic variables without flux correction. The major focus of this work is on oceanic properties. First, the coupled simulation is assessed against ocean-only simulations carried out under two different sets of air-sea heat fluxes. The first set, provided by the MITgcm, is proved to be grossly deficient as the heat fluxes are evaluated by a two-dimensional, zonally averaged atmosphere and the simulated SST have anomalous cold biases. Hence the MITgcm fluxes are discarded. The second set, the NCEP re-analysis heat fluxes, produces a climatological evolution of the SST with an average cold bias of ~-0.8 °C. The coupling eliminates the cold bias and the coupled SST evolution is in excellent agreement with the analogous evolution in the SODA re-analysis data. The detailed comparison of oceanic circulation properties with the International Nusantara Stratification and Transport observations shows that the coupled simulation produces the best estimate of the total ITF transport through the Makassar strait while the transports of three ocean-only simulations are all underestimated. The annual cycle of the transport is also very well reproduced. The coupling also

  12. Local and regional factors influencing bacterial community assembly.

    PubMed

    Lindström, Eva S; Langenheder, Silke

    2012-02-01

    The classical view states that microbial biogeography is not affected by dispersal barriers or historical events, but only influenced by the local contemporary habitat conditions (species sorting). This has been challenged during recent years by studies suggesting that also regional factors such as mass effect, dispersal limitation and neutral assembly are important for the composition of local bacterial communities. Here we summarize results from biogeography studies in different environments, i.e. in marine, freshwater and soil as well in human hosts. Species sorting appears to be the most important mechanism. However, this result might be biased since this is the mechanism that is easiest to measure, detect and interpret. Hence, the importance of regional factors may have been underestimated. Moreover, our survey indicates that different assembly mechanisms might be important for different parts of the total community, differing, for example, between generalists and specialists, and between taxa of different dispersal ability and motility. We conclude that there is a clear need for experimental studies, first, to clearly separate regional and local factors in order to study their relative importance, and second, to test whether there are differences in assembly mechanisms depending on different taxonomic or functional groups.

  13. Evaluating Observation Influence on Regional Water Budgets in Reanalyses

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Chern, Jiun-Dar; Mocko, David; Robertson, Franklin R.; daSilva, Arlindo M.

    2014-01-01

    The assimilation of observations in reanalyses incurs the potential for the physical terms of budgets to be balanced by a term relating the fit of the observations relative to a forecast first guess analysis. This may indicate a limitation in the physical processes of the background model, or perhaps inconsistencies in the observing system and its assimilation. In the MERRA reanalysis, an area of long term moisture flux divergence over land has been identified over the Central United States. Here, we evaluate the water vapor budget in this region, taking advantage of two unique features of the MERRA diagnostic output; 1) a closed water budget that includes the analysis increment and 2) a gridded diagnostic output data set of the assimilated observations and their innovations (e.g. forecast departures). In the Central United States, an anomaly occurs where the analysis adds water to the region, while precipitation decreases and moisture flux divergence increases. This is related more to a change in the observing system than to a deficiency in the model physical processes. MERRAs Gridded Innovations and Observations (GIO) data narrow the observations that influence this feature to the ATOVS and Aqua satellites during the 06Z and 18Z analysis cycles. Observing system experiments further narrow the instruments that affect the anomalous feature to AMSUA (mainly window channels) and AIRS. This effort also shows the complexities of the observing system, and the reactions of the regional water budgets in reanalyses to the assimilated observations.

  14. Regional and Local Carbon Flux Information from a Continuous Atmospheric CO2 Network in the Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Heck, S. L.; Stephens, B.; Watt, A.

    2007-12-01

    We will present preliminary carbon flux estimates from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON). In order to improve our understanding of regional carbon fluxes in the Rocky Mountain West, we have developed and deployed autonomous, inexpensive, and robust CO2 analyzers (AIRCOA) at five sites throughout Colorado and Utah, and plan additional deployments on the Navajo Reservation, Arizona in September 2007 and atop Mount Kenya, Africa in November 2007. We have used a one- dimensional CO2 budget equation, following Bakwin et al. (2004), to estimate regional monthly-mean fluxes from our continuous CO2 concentrations. These comparisons between our measurements and estimates of free- tropospheric background concentrations reveal regional-scale CO2 flux signals that are generally consistent with one another across the Rocky RACCOON sites. We will compare the timing and magnitude of these estimates with expectations from local-scale eddy-correlation flux measurements and bottom-up ecosystem models. We will also interpret the differences in monthly-mean flux signals between our sites in terms of their varying upwind areas of influence and inferred regional variations in CO2 fluxes. Our measurements will be included in future CarbonTracker assimilation runs and other planned model-data fusion efforts. However, questions still exist concerning the ability of these models to accurately represent the various influences on CO2 concentrations in continental boundary layers, and at mountaintop sites in particular. We will present an analysis of the diurnal cycles in CO2 concentration and CO2 variability at our sites, and compare these to various model estimates. Several of our sites near major population centers reflect the influence of industrial CO2 sources in afternoon upslope flows, with CO2 concentration increasing and variable in the mid to late afternoon. Other more remote sites show more consistent and decreasing CO2

  15. Seeing the Forest Through the Trees: Investigating Signal to Noise Problems in Regional Atmospheric Inversions

    NASA Astrophysics Data System (ADS)

    Schuh, A. E.; Denning, A. S.; Corbin, K. D.; Uliasz, M.; Zupanski, D.; Parazoo, N. C.

    2007-12-01

    Estimation of regional carbon fluxes from sparse atmospheric data by transport inversion is complicated by high- frequency variations in surface fluxes in both space and time. We assume that a forward coupled model of the vegetated land surface and atmosphere adequately captures most of the high-frequency variations (SiB-RAMS) as a `preprocessor` of input data from remote sensing and large-scale weather. We then use continuous CO2 observations and backward-in-time Lagrangian particle modeling to estimate persistent multiplicative biases in photosynthesis and ecosystem respiration, constraining the temporal pattern of these fluxes with the forward model. With a sparse network of continuous observing sites in North America, the inverse problem is still badly underconstrained for flux biases on the model grid scale. Previous studies have reduced the dimensionality of this problem by using large `regions` such as biomes or ecoregions, or by seeking a smooth solution in space. This could introduce substantial bias in the solution because the actual flux biases are likely to be quite heterogeneous. We have evaluated the degree to which carbon flux over large regions (500 to 1500 km) can be recovered when the true spatial pattern is not smooth. We performed ensembles of inversions for a 4-month case study in May- August, 2004 over North America with synthetic mid-day CO2 observations from a network of 8 towers. A smooth regional field of model biases was superposed with ensembles of various degrees of grid-scale `noise,` and these were then used to create synthetic concentration data. The pseudodata were then inverted to estimate gridded values of the biases, which were then combined with time-varying model fluxes to create regional maps of sources and sinks. We found that the degree to which corrections in regional fluxes are possible will depend on the relative amount of variance in the regional vs grid scales, but that the system is quite successful in estimating

  16. RSL: A parallel Runtime System Library for regional atmospheric models with nesting

    SciTech Connect

    Michalakes, J.G.

    1997-08-01

    RSL is a parallel runtime system library developed at Argonne National Laboratory that is tailored to regular-grid atmospheric models with mesh refinement in the form of two-way interacting nested grids. RSL provides high-level stencil and interdomain communication, irregular domain decomposition, automatic local/global index translation, distributed I/O, and dynamic load balancing. RSL was used with Fortran90 to parallelize a well-known and widely used regional weather model, the Penn State/NCAR Mesoscale model.

  17. Estimation on the influence of uncertain parameters on stochastic thermal regime of embankment in permafrost regions

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Zhou, Guoqing; Wang, Jianzhou; Zhao, Xiaodong; Chen, Xing

    2016-07-01

    For embankments in permafrost regions, the soil properties and the upper boundary conditions are stochastic because of complex geological processes and changeable atmospheric environment. These stochastic parameters lead to the fact that conventional deterministic temperature field of embankment become stochastic. In order to estimate the influence of stochastic parameters on random temperature field for embankment in permafrost regions, a series of simulated tests are conducted in this study. We consider the soil properties as random fields and the upper boundary conditions as stochastic processes. Taking the variability of each stochastic parameter into account individually or concurrently, the corresponding random temperature fields are investigated by Neumann stochastic finite element method. The results show that both of the standard deviation under the embankment and the boundary increase with time when considering the stochastic effect of soil properties and boundary conditions. Stochastic boundary conditions and soil properties play a different role in random temperature field of embankment at different times. Each stochastic parameter has a different effect on random temperature field. These results can improve our understanding of the influence of stochastic parameters on random temperature field for embankment in permafrost regions.

  18. Extreme regimes of atmospheric circulation and their role in the formation of temperature and precipitation fields in the Arctic region

    NASA Astrophysics Data System (ADS)

    Irina, Kulikova; Ekaterina, Kruglova; Dmitry, Kiktev; Vladimir, Tischenco; Valentina, Khan

    2016-04-01

    In the present study, the extreme regimes of atmospheric circulation in the Northern Hemisphere as well as their role in the formation of monthly and seasonal anomalies of temperature and precipitation fields over Arctic region were examined using NCEP / NCAR-2 reanalysis data. To identify extreme modes, climate indexes were quantitatively assessed. The mapping of monthly and seasonal temperature and precipitation fields for the different phases of indices using composite analysis was developed. It is allowed to identify allocated geographic areas in which the influence of modes of circulation for temperature and precipitation fields in Arctic is statistically significant. Quantitative estimations of contingency of atmospheric circulation modes in the Northern Hemisphere were analyzed. Special attention has been paid to the extreme episodes of the climate circulation indices, associated with formation of significant anomalies of air temperature and precipitation. The results of numerical experiments to reproduce the extreme events on monthly and seasonal time scale on the basis of the global semi-Lagrangian model SL-AV, developed in collaboration of Institute of Numerical Mathematics and Hydrometeorological Centre of Russia, have been discussed. For this study the support has been provided by Grant of Russian Science Foundation (№14-37-00053).

  19. Lessons Learned from the Bay Region Atmospheric Chemistry Experiment (BRACE) and Implications for Nitrogen Management of Tampa Bay

    EPA Science Inventory

    Results from air quality modeling and field measurements made as part of the Bay Region Atmospheric Chemistry Experiment (BRACE) along with related scientific literature were reviewed to provide an improved estimate of atmospheric reactive nitrogen (N) deposition to Tampa Bay, to...

  20. Incidence of atmospheric pollen in the Pretoria-Witwatersrand-Vereeniging region during 1987/1988.

    PubMed

    Cadman, A

    1991-01-19

    Atmospheric pollen and spores have been monitored continuously in the Pretoria-Witwatersrand-Vereeniging region (PWV) since 1987. Two Burkard 7-day recording traps were used in Johannesburg and Pretoria, and 11 gravity samplers were installed at various sites in the PWV. An analysis of the pollen component and pollen calendars average data for 1987 and 1988 are presented. Grass pollen was the most significant contributor in absolute and relative terms, comprising 52% of total pollen. The season peaked between October and March, but grass pollen was found throughout the year. Pollen of Northern Hemisphere trees was abundant, relative to that of indigenous trees. The flowering season for these exotics was very short and intense, possibly due to the short spring season. Seasonal taxa started flowering earlier in Pretoria than in Johannesburg. Herbaceous taxa were well represented in the atmospheric sample. The major contributor was the daisy family. The greatest proportion of pollen, 58.8%, was non-seasonal. Species in this category flower consecutively throughout the year. Of the taxa, 28.4% were spring-flowering. The allergenicity of pollen encountered in the atmospheric sample is discussed.

  1. Surface–Atmosphere Moisture Interactions in the Frozen Ground Regions of Eurasia

    PubMed Central

    Ford, Trent W.; Frauenfeld, Oliver W.

    2016-01-01

    Climate models simulate an intensifying Arctic hydrologic cycle in response to climatic warming, however the role of surface-atmosphere interactions from degrading frozen ground is unclear in these projections. Using Modern-Era Retrospective Analysis for Research and Applications (MERRA) data in high-latitude Eurasia, we examine long-term variability in surface-atmosphere coupling as represented by the statistical relationship between surface evaporative fraction (EF) and afternoon precipitation. Changes in EF, precipitation, and their statistical association are then related to underlying permafrost type and snow cover. Results indicate significant positive trends in July EF in the Central Siberian Plateau, corresponding to significant increases in afternoon precipitation. The positive trends are only significant over continuous permafrost, with non-significant or negative EF and precipitation trends over isolated, sporadic, and discontinuous permafrost areas. Concurrently, increasing EF and subsequent precipitation are found to coincide with significant trends in May and June snowmelt, which potentially provides the moisture source for the observed enhanced latent heating and moisture recycling in the region. As climate change causes continuous permafrost to transition to discontinuous, discontinuous to sporadic, sporadic to isolated, and isolated permafrost disappears, this will also alter patterns of atmospheric convection, moisture recycling, and hence the hydrologic cycle in high-latitude land areas. PMID:26777288

  2. A new approach to the convective parameterization of the regional atmospheric model BRAMS

    NASA Astrophysics Data System (ADS)

    Dos Santos, A. F.; Freitas, S. R.; de Campos Velho, H. F.; Luz, E. F.; Gan, M. A.; de Mattos, J. Z.; Grell, G. A.

    2013-05-01

    The summer characteristics of January 2010 was performed using the atmospheric model Brazilian developments on the Regional Atmospheric Modeling System (BRAMS). The convective parameterization scheme of Grell and Dévényi was used to represent clouds and their interaction with the large scale environment. As a result, the precipitation forecasts can be combined in several ways, generating a numerical representation of precipitation and atmospheric heating and moistening rates. The purpose of this study was to generate a set of weights to compute a best combination of the hypothesis of the convective scheme. It is an inverse problem of parameter estimation and the problem is solved as an optimization problem. To minimize the difference between observed data and forecasted precipitation, the objective function was computed with the quadratic difference between five simulated precipitation fields and observation. The precipitation field estimated by the Tropical Rainfall Measuring Mission satellite was used as observed data. Weights were obtained using the firefly algorithm and the mass fluxes of each closure of the convective scheme were weighted generating a new set of mass fluxes. The results indicated the better skill of the model with the new methodology compared with the old ensemble mean calculation.

  3. Assessment of dynamical downscaling in Japan using an atmosphere-biosphere-river coupling regional climate model

    NASA Astrophysics Data System (ADS)

    Dairaku, K.; Iizuka, S.; Sasaki, W.; Beltran, A.; Pielke, R. A.

    2008-12-01

    The responses of the climate system to increases in carbon dioxide concentrations and to changes in land use/land cover and the subsequent impacts of climatic variability on humans and natural ecosystems are of fundamental concern. Because regional responses of surface hydrological and biogeochemical changes are particularly complex, it is necessary to add spatial resolution to accurately assess critical interactions within the regional climate system for climate change impacts assessments. We investigated the reproducibility of present climate using two regional climate models with 20km horizontal grid spacing, the atmosphere- biosphere-river coupling regional climate model(GEMRAMS) and the Meteorological Research Institute Nonhydrostatic Model(MRI-NHM), both of which used Japanese 25-year ReAnalysis (JRA-25) as lateral boundary conditions. Two key variables for impact studies, surface air temperature and precipitation, were compared with the Japanese high-resolution surface observation, Automated Meteorological Data Acquisition System (AMeDAS) on 78 river basins. Results simulated by the two models were relatively in good agreement with the observation on the basin scale. The differences of surface air temperature between the models and the observation were less than 2K and the ratio of precipitation of the models to the observation was within 0.5-2 on seasonal averages. By adding other two regional climate models, a multi-model ensemble will be applied in climate change impact studies in combination with additional statistical downscaling approaches.

  4. Regional association analysis delineates a sequenced chromosome region influencing antinutritive seed meal compounds in oilseed rape.

    PubMed

    Snowdon, R J; Wittkop, B; Rezaidad, A; Hasan, M; Lipsa, F; Stein, A; Friedt, W

    2010-11-01

    This study describes the use of regional association analyses to delineate a sequenced region of a Brassica napus chromosome with a significant effect on antinutritive seed meal compounds in oilseed rape. A major quantitative trait locus (QTL) influencing seed colour, fibre content, and phenolic compounds was mapped to the same position on B. napus chromosome A9 in biparental mapping populations from two different yellow-seeded × black-seeded B. napus crosses. Sequences of markers spanning the QTL region identified synteny to a sequence contig from the corresponding chromosome A9 in Brassica rapa. Remapping of sequence-derived markers originating from the B. rapa sequence contig confirmed their position within the QTL. One of these markers also mapped to a seed colour and fibre QTL on the same chromosome in a black-seeded × black-seeded B. napus cross. Consequently, regional association analysis was performed in a genetically diverse panel of dark-seeded, winter-type oilseed rape accessions. For this we used closely spaced simple sequence repeat (SSR) markers spanning the sequence contig covering the QTL region. Correction for population structure was performed using a set of genome-wide SSR markers. The identification of QTL-derived markers with significant associations to seed colour, fibre content, and phenolic compounds in the association panel enabled the identification of positional and functional candidate genes for B. napus seed meal quality within a small segment of the B. rapa genome sequence.

  5. The Influence of CO2 Admixtures on the Product Composition in a Nitrogen-Methane Atmospheric Glow Discharge Used as a Prebiotic Atmosphere Mimic

    NASA Astrophysics Data System (ADS)

    Mazankova, V.; Torokova, L.; Krcma, F.; Mason, N. J.; Matejcik, S.

    2016-11-01

    This work extends our previous experimental studies of the chemistry of Titan's atmosphere by atmospheric glow discharge. The Titan's atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the interest about prebiotic atmospheres. Present work is devoted to the role of CO2 in the prebiotic atmosphere chemistry. Most of the laboratory studies of such atmosphere were focused on the chemistry of N2 + CH4 mixtures. The present work is devoted to the study of the oxygenated volatile species in prebiotic atmosphere, specifically CO2 reactivity. CO2 was introduced to the standard N2 + CH4 mixture at different mixing ratio up to 5 % CH4 and 3 % CO2. The reaction products were characterized by FTIR spectroscopy. This work shows that CO2 modifies the composition of the gas phase with the detection of oxygenated compounds: CO and others oxides. There is a strong influence of CO2 on increasing concentration other products as cyanide (HCN) and ammonia (NH3).

  6. The Influence of CO2 Admixtures on the Product Composition in a Nitrogen-Methane Atmospheric Glow Discharge Used as a Prebiotic Atmosphere Mimic

    NASA Astrophysics Data System (ADS)

    Mazankova, V.; Torokova, L.; Krcma, F.; Mason, N. J.; Matejcik, S.

    2016-04-01

    This work extends our previous experimental studies of the chemistry of Titan's atmosphere by atmospheric glow discharge. The Titan's atmosphere seems to be similarly to early Earth atmospheric composition. The exploration of Titan atmosphere was initiated by the exciting results of the Cassini-Huygens mission and obtained results increased the interest about prebiotic atmospheres. Present work is devoted to the role of CO2 in the prebiotic atmosphere chemistry. Most of the laboratory studies of such atmosphere were focused on the chemistry of N2 + CH4 mixtures. The present work is devoted to the study of the oxygenated volatile species in prebiotic atmosphere, specifically CO2 reactivity. CO2 was introduced to the standard N2 + CH4 mixture at different mixing ratio up to 5 % CH4 and 3 % CO2. The reaction products were characterized by FTIR spectroscopy. This work shows that CO2 modifies the composition of the gas phase with the detection of oxygenated compounds: CO and others oxides. There is a strong influence of CO2 on increasing concentration other products as cyanide (HCN) and ammonia (NH3).

  7. Atmospheric wave-induced instability in the nighttime E-region.

    NASA Technical Reports Server (NTRS)

    Beer, T.; Moorcroft, D. R.

    1972-01-01

    Examination of the perturbed continuity equation when the perturbations are the result of an internal atmospheric gravity wave in the E region. The transient response of the ionization is interpreted as the gradient instability and the values of the vertical and horizontal wave numbers that will induce it are plotted for various heights. Only in the presence of westward directed electric fields, which are believed to occur only at night, will the gravity waves induce the gradient instability. Approximate analytic expressions are obtained for the permitted wave numbers as well as for the instability growth times. In the course of this analysis it is shown that in the D region all irregularities, even those that are field-aligned, will tend to move with the ion velocity.

  8. Structure of the disturbed region of the atmosphere after the nuclear explosion in Hiroshima

    NASA Astrophysics Data System (ADS)

    Shcherbin, M. D.; Pavlyukov, K. V.; Salo, A. A.; Pertsev, S. F.; Rikunov, A. V.

    2013-09-01

    An attempt is undertaken to describe the development of the disturbed region of the atmosphere caused by the nuclear explosion over Hiroshima on August 6, 1945. Numerical simulation of the phenomenon is performed using the dynamic equations for a nonconducting inviscid gas taking into account the combustion of urban buildings, phase changes of water, electrification of ice particles, and removal of soot particles. The results of the numerical calculation of the development of the disturbed region indicate heavy rainfall, the formation of a storm cloud with lightning discharges, removal of soot particles, and the formation of vertical vortices. The temporal sequence of these meteorological phenomena is consistent with the data of observations. Because of the assumptions and approximations used in solving the problem, the results are of qualitative nature. Refinement of the results can be obtained by a more detailed study of the approximate initial and boundary conditions of the problem.

  9. Investigation Spectral Image the Upper Atmosphere over Regions with Thunderstorm Using Data from the Sv

    NASA Astrophysics Data System (ADS)

    Grichshenko, Valentina

    2016-07-01

    The results of the two-level experiment, including registration of the electric field in the surface layer during thunderstorm on TSCRS (Almaty) and synchronous image the top of the cloud cover over the test range from satellite "Terra / MODIS" are presented. Spectral image of the upper atmosphere over of the thunderstorm related to lighting discharge has been created. As a result of the processing of satellite images Terra / MODIS created a new index of "lightning discharge," which will be used to search for and investigation of optical phenomena (such as Sprites, Elves, Blue Jet) over the regions with thunderstorm activity. The developed technique of space picture processing will be used for studying optical phenomena above other regions too.

  10. Tracing industrial ammonium in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Mayer, B.; Proemse, B. C.; Fenn, M. E.

    2013-12-01

    The expanding industrial development in the Athabasca oil sands region (AOSR) in northeastern Alberta, Canada, has raised concerns about increasing nitrogen (N) emissions from oil sands operations and their potential effects on the surrounding terrestrial and aquatic ecosystems. Stable isotope techniques may help to trace industrial emissions provided that they are isotopically distinct from background isotope ratios of atmospheric N compounds. Ammonium deposition rates (NH4-N) typically exceed nitrate deposition rates (NO3-N) in the AOSR (Proemse et al., 2013), suggesting that emissions of reduced nitrogen compounds play a significant role for the atmospheric nitrogen budget in the AOSR. We collected atmospheric ammonium in open field bulk deposition and throughfall using ion exchange resins over ~6 months time periods from summer 2007 to summer 2011 located at distances between 3 to 113 km to one of the major oil sands developments in the AOSR. Ammonium deposition rates and δ15N-NH4 values were determined using ion chromatography and the ammonium diffusion method (Sebilo et al., 2004) on resin extracts. Atmospheric ammonium deposition rates in open field bulk collectors and throughfall collectors ranged from 1.0 to 4.7 kg ha-1 yr-1 NH4-N, and from 1.0 to 18.3 kg ha-1 yr-1 NH4-N, respectively. δ15N-NH4 values varied from -6.3 to +14.8‰ with the highest δ15N values typically associated with elevated NH4-N deposition rates. δ15N-NH4 values of up to +20.1‰ were observed for industrially emitted NH4 in particulate matter (PM2.5) emissions (Proemse et al., 2012) suggesting that industrial NH3 and NH4 emissions are associated with elevated δ15N values providing a potential tracer. Applying a two-end-member mixing analysis using a background δ15N-NH4 value of -3.6‰ for summer and -3.2‰ for winter periods revealed that particularly sites within ~30 km radius from the main oil sands developments are significantly affected by industrial contributions to

  11. Atmosphere

    NASA Astrophysics Data System (ADS)

    Ghosh, D.; Mitra, S. K.

    2014-05-01

    This paper investigates the high-temperature corrosion behavior of microstructurally different regions of the weldment of 9 Cr-1 Mo steel used in thermal power plant boiler in SO2 + O2 environment. The weldment is produced by tungsten inert gas welding method, and the different regions of the weldment (weld metal, heat-affected zone, and base metal) are exposed in SO2 + O2 (ratio 2:1) environment at 973 K for 120 h. The reaction kinetics and corrosion growth rate of different regions of weldment in isothermal condition are evaluated. The post corroded scales of the different specimens are studied in SEM, EDS, and XRD. The results indicate that the weld metal shows higher corrosion rate followed by HAZ and base metal. The higher rate of corrosion of weldmetal is mainly attributed to the least protective inner scale of Cr2O3 with minimum Cr Content. This is due to the formation of delta ferrite, which leads to the precipitation of the Cr-based secondary phases and depletes the free Cr from the matrix. The thermal cycles during welding at high temperature are favorable for the formation of delta ferrite. On the other hand, in absence of delta ferrite, the base metal and HAZ regions of the weldment show lower corrosion rate than weld metal. The difference in corrosion rate in the three regions of the weldment is supplemented by post-corroded scale characterizations.

  12. Spatial Variation of Soil Type and Soil Moisture in the Regional Atmospheric Modeling System

    SciTech Connect

    Buckley, R.

    2001-06-27

    Soil characteristics (texture and moisture) are typically assumed to be initially constant when performing simulations with the Regional Atmospheric Modeling System (RAMS). Soil texture is spatially homogeneous and time-independent, while soil moisture is often spatially homogeneous initially, but time-dependent. This report discusses the conversion of a global data set of Food and Agriculture Organization (FAO) soil types to RAMS soil texture and the subsequent modifications required in RAMS to ingest this information. Spatial variations in initial soil moisture obtained from the National Center for Environmental Predictions (NCEP) large-scale models are also introduced. Comparisons involving simulations over the southeastern United States for two different time periods, one during warmer, more humid summer conditions, and one during cooler, dryer winter conditions, reveals differences in surface conditions related to increases or decreases in near-surface atmospheric moisture con tent as a result of different soil properties. Three separate simulation types were considered. The base case assumed spatially homogeneous soil texture and initial soil moisture. The second case assumed variable soil texture and constant initial soil moisture, while the third case allowed for both variable soil texture and initial soil moisture. The simulation domain was further divided into four geographically distinct regions. It is concluded there is a more dramatic impact on thermodynamic variables (surface temperature and dewpoint) than on surface winds, and a more pronounced variability in results during the summer period. While no obvious trends in surface winds or dewpoint temperature were found relative to observations covering all regions and times, improvement in surface temperatures in most regions and time periods was generally seen with the incorporation of variable soil texture and initial soil moisture.

  13. Contribution of regional sources to atmospheric methane over the Amazon Basin in 2010 and 2011

    NASA Astrophysics Data System (ADS)

    Wilson, Chris; Gloor, Manuel; Gatti, Luciana V.; Miller, John B.; Monks, Sarah A.; McNorton, Joey; Bloom, A. Anthony; Basso, Luana S.; Chipperfield, Martyn P.

    2016-03-01

    We present an assessment of methane (CH4) atmospheric concentrations over the Amazon Basin for 2010 and 2011 using a 3-D atmospheric chemical transport model, two wetland emission models, and new observations made during biweekly flights made over four locations within the basin. We attempt to constrain basin-wide CH4 emissions using the observations, and since 2010 was an unusually dry year, we assess the effect of this drought on Amazonian methane emissions. We find that South American emissions contribute up to 150 ppb to concentrations at the sites, mainly originating from within the basin. Our atmospheric model simulations agree reasonably well with measurements at three of the locations (0.28 ≤ r2 ≤ 0.63, mean bias ≤ 9.5 ppb). Attempts to improve the simulated background CH4 concentration through analysis of simulated and observed sulphur hexafluoride concentrations do not improve the model performance, however. Through minimisation of seasonal biases between the simulated and observed atmospheric concentrations, we scale our prior emission inventories to derive total basin-wide methane emissions of 36.5-41.1 Tg(CH4)/yr in 2010 and 31.6-38.8 Tg(CH4)/yr in 2011. These totals suggest that the Amazon contributes significantly (up to 7%) to global CH4 emissions. Our analysis indicates that factors other than precipitation, such as temperature variations or tree mortality, may have affected microbial emission rates. However, given the uncertainty of our emission estimates, we cannot say definitively whether the noncombustion emissions from the region were different in 2010 and 2011, despite contrasting meteorological conditions between the two years.

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

    SciTech Connect

    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.

  15. Predicting wetland contamination from atmospheric deposition measurements of pesticides in the Canadian Prairie Pothole region

    NASA Astrophysics Data System (ADS)

    Messing, Paul G.; Farenhorst, Annemieke; Waite, Don T.; McQueen, D. A. Ross; Sproull, James F.; Humphries, David A.; Thompson, Laura L.

    2011-12-01

    Although it has been suggested that atmospheric deposition alone can result in detectable levels of pesticides in wetlands of the Pairie Pothole Region of Canada, this is the first field study to compare the masses of pesticides entering wetlands by atmospheric deposition with those concentrations of pesticides detected in the water-column of prairie wetlands. Weekly air and bulk deposition samples were collected from May 26th to Sept. 15th, 2008 at the Manitoba Zero Tillage Research Association (MZTRA) Farm, Brandon, Manitoba, with four on-site wetlands (approximate sizes 0.15-0.45 ha) monitored every second week. Twelve pesticides were detected in the air, with MCPA (one of the three pesticides applied on the farm in 2008 in addition to clopyralid and glyphosate), triallate, and γ-HCH being detected every week. Calculations were performed to predict wetland pesticide concentrations based on bulk deposits alone for those pesticides that had detectable concentrations in the bulk deposition samples (in order of the highest total seasonal deposition mass to the lowest): MCPA, glyphosate, 2,4-D, clopyralid, bromoxynil, atrazine, dicamba, metolachlor, and mecoprop. The estimated concentrations were closest to actual concentrations for MCPA (Pearson correlation coefficient's = 0.91 to 0.98; p-values < 0.001) and predictions were also reasonable for a range of other herbicides, but a source other than atmospheric deposition was clearly relevant to detections of clopyralid in the wetland water-column. Although the types and levels of pesticides detected in the wetlands of the current study suggest that regional pesticide applications can contribute to pesticide surface water contamination following atmospheric transport and deposition, the greater frequency and concentrations of clopyralid, MCPA, and glyphosate detections in wetlands confirm that on-farm pesticide applications have a greater impact on on-site water quality. Beneficial management practices that reduce

  16. Projected changes in atmospheric river events in Arizona as simulated by global and regional climate models

    NASA Astrophysics Data System (ADS)

    Rivera, Erick R.; Dominguez, Francina

    2015-12-01

    Inland-penetrating atmospheric rivers (ARs) affect the United States Southwest and significantly contribute to cool season precipitation. In this study, we examine the results from an ensemble of dynamically downscaled simulations from the North American Regional Climate Change Assessment Program (NARCCAP) and their driving general circulation models (GCMs) in order to determine statistically significant changes in the intensity of the cool season ARs impacting Arizona and the associated precipitation. Future greenhouse gas emissions follow the A2 emission scenario from the Intergovernmental Panel on Climate Change Fourth Assessment Report simulations. We find that there is a consistent and clear intensification of the AR-related water vapor transport in both the global and regional simulations which reflects the increase in water vapor content due to warmer atmospheric temperatures, according to the Clausius-Clapeyron relationship. However, the response of AR-related precipitation intensity to increased moisture flux and column-integrated water vapor is weak and no significant changes are projected either by the GCMs or the NARCCAP models. This lack of robust precipitation variations can be explained in part by the absence of meaningful changes in both the large-scale water vapor flux convergence and the maximum positive relative vorticity in the GCMs. Additionally, some global models show a robust decrease in relative humidity which may also be responsible for the projected precipitation patterns.

  17. Dynamical Downscaling NCEP Global Climate Forecast System (CFS) Seasonal Predictions Using Regional Atmospheric Modeling System (RAMS)

    NASA Astrophysics Data System (ADS)

    Lu, L.; Zheng, Y.; Pielke, R. A.

    2009-12-01

    As part of the NOAA CPPA-sponsored MRED project, the state-of-the-art Regional Atmospheric Modeling System (RAMS) version 6.0 is used to dynamically and progressively downscale NCEP global Climate Forecast System (CFS, at 100s-km grid increment) seasonal predictions to a regional domain that covers the conterminous United States at 30-km grid increment. The first set of RCM prediction experiment focuses on the winter seasons, during which the precipitation is largely dependent on synoptic-scale mid-latitude storms and orographic dominant mesoscale processes. Our first suite of numerical experiment includes one ensemble member for each year from 1982 through 2008, with all the simulations starting on December 1 and ending on April 30. Driven by the same atmospheric and SST forcings, RAMS will be compared with other RCMs, and evaluated against observations and reanalysis (NARR) to see if the simulations capture the climatology and interannual variability of temperature and precipitation distributions. The overall strengths and weaknesses of the modeling systems will be identified, as well as the consistent model biases. In addition, we will analyze the changes in kinetic energy spectra before and after the spectral nudging algorithm is implemented. The results show that with the spectral nudging scheme, RAMS can better preserve large-scale kinetic energy than standard boundary forcing method, and allow more large-scale energy to cascade to smaller scales.

  18. Projected changes in atmospheric river events in Arizona as simulated by global and regional climate models

    NASA Astrophysics Data System (ADS)

    Rivera, Erick R.; Dominguez, Francina

    2016-09-01

    Inland-penetrating atmospheric rivers (ARs) affect the United States Southwest and significantly contribute to cool season precipitation. In this study, we examine the results from an ensemble of dynamically downscaled simulations from the North American Regional Climate Change Assessment Program (NARCCAP) and their driving general circulation models (GCMs) in order to determine statistically significant changes in the intensity of the cool season ARs impacting Arizona and the associated precipitation. Future greenhouse gas emissions follow the A2 emission scenario from the Intergovernmental Panel on Climate Change Fourth Assessment Report simulations. We find that there is a consistent and clear intensification of the AR-related water vapor transport in both the global and regional simulations which reflects the increase in water vapor content due to warmer atmospheric temperatures, according to the Clausius-Clapeyron relationship. However, the response of AR-related precipitation intensity to increased moisture flux and column-integrated water vapor is weak and no significant changes are projected either by the GCMs or the NARCCAP models. This lack of robust precipitation variations can be explained in part by the absence of meaningful changes in both the large-scale water vapor flux convergence and the maximum positive relative vorticity in the GCMs. Additionally, some global models show a robust decrease in relative humidity which may also be responsible for the projected precipitation patterns.

  19. Evidence of the observed change in the atmosphere-ocean interactions over the South China Sea during summer in a regional climate model

    NASA Astrophysics Data System (ADS)

    Jang, Hye-Yeong; Yeh, Sang-Wook; Chang, Eun-Chul; Kim, Baek-Min

    2016-10-01

    The South China Sea plays a key role to change the precipitation variability in East Asia by influencing the northward moisture transport. Previous study found that there exist changes in atmosphere-ocean interactions over the South China Sea (SCS) before and after the late 1990s during boreal summer (June-July-August) in the observations. This study further supports such changes using two simulations of the atmospheric regional climate model (RCM) forced by historical sea surface temperature (SST). The control run is forced by historical SSTs, which are prescribed in the entire domain in the RCM. In addition to the control run, an additional idealized experiment is conducted, i.e., the historical SSTs are prescribed in the SCS only and the climatological SST is prescribed outside the SCS to examine the changes in the atmosphere-ocean interactions in the SCS. It is found that the simultaneous correlation coefficient between SST and precipitation changes significantly over the SCS before and after the late 1990s. This result supports the notion that there are significant changes in atmosphere-ocean interactions over the SCS before and after the late 1990, which affects the ability of the RCM to simulate precipitation variability accurately relative to observation. This result implies that the simulations of atmospheric circulation model results forced by observed SST before the late 1990 should be cautiously interpreted because the observed SST anomalies are forced by the atmosphere.

  20. The oxygen red OI 630.0 nm line nightglow intensity as an indicator of atmospheric waves propagation in the mid-latitude ionosphere F2 region

    NASA Astrophysics Data System (ADS)

    Javakhishvili, Giorgi; Didebulidze, Goderdzi; Gudadze, Nikoloz; Toriashvili, Lexo

    2016-04-01

    The behavior of the oxygen red OI 630.0 nm line nightglow intensity under influence of atmospheric gravity waves (AGWs) is considered, taking into account nightly changes of the thermosphere meridional wind by observations from Abastumani (41.75 N; 42.82 E). The vortical type perturbations, which can be in situ excited, are also considered. On the basis of theoretical model, the 630.0 nm line integral intensity variations are estimated taking into account thermosphere wind field changes and atmospheric waves propagation influence on the nighttime ionosphere F2 layer. A possibility of identification of waves propagation from polar and equatorial regions during various helio-geophysical conditions is noted. The cases of detected large scale traveling ionosphere disturbances -TIDs (mostly generated in the polar regions) and traveling atmospheric disturbances -TADs (which can be generated both in polar and equatorial regions) are demonstrated. Acknowledgements: This work has been supported by Shota Rustaveli National Science Foundation Grant no. 31/56.

  1. Towards a regional CO2 budget for New Zealand from atmospheric measurements and backward Lagrangian modeling

    NASA Astrophysics Data System (ADS)

    Steinkamp, K.; Mikaloff-Fletcher, S.; Brailsford, G. W.; Moore, S.

    2013-12-01

    Between 1990 and 2011, the reported average annual growth in total greenhouse gas emissions had been 1.0% for New Zealand, with emissions reaching 73 Mt CO2-e in 2011. At the same time the net emissions (total plus LULUCF) grew by 4.2% each year on average and reached 59 Mt CO2-e in 2011, according to the Ministry for the Environment. This implies a shrinking sink for greenhouse gases in areas of land use/ land use change and forests (LULUCF). The uptake of CO2 by forests is the largest contributor to this sink and, therefore, plays a crucial role in New Zealand's carbon budget. Yet, it is among the least well-known components. In this study, we aim to develop a regional atmosphere inversion system to estimate net CO2 uptake by land areas in 2011 and 2012. This will serve as an alternative to the bottom-up estimates outlined above. We use the UK Met Office's Lagrangian dispersion model NAME III to link CO2 measurements at stations directly to atmospheric transport and potential source regions at the surface. By running the model in backward mode, we identify the degree to which potential regional sources of CO2 contribute to observed mid-afternoon mixing ratios, i.e., the footprint of a station. Footprints are computed over 2011-2012 for three stations across New Zealand: Baring Head, Lauder and Rainbow Mountain. NAME III uses hourly meteorological input from the regional forecast model NZLAM-12 over a domain covering New Zealand and the Tasman Sea at a horizontal resolution of 12 km. The footprints are then used in a regional inversion to find the optimal distribution of CO2 sources and sinks, i.e., the one leading to the best match with the measurements at all stations. We present results from the footprint analysis and show that the three stations are sensitive to distinct source regions that do not overlap and, together, cover large parts of New Zealand. Hence, the data from the stations carry complementary information on CO2 sinks in sources throughout the

  2. Influence of the Cardiac Myosin Hinge Region on Contractile Activity

    NASA Astrophysics Data System (ADS)

    Margossian, Sarkis S.; Krueger, John W.; Sellers, James R.; Cuda, Giovanni; Caulfield, James B.; Norton, Paul; Slayter, Henry S.

    1991-06-01

    The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin. This antibody bound specifically at the hinge at a distance of 55 nm from the S1/S2 junction, was specific to human, dog, and rat cardiac myosins, did not crossreact with gizzard or skeletal myosin, and had no effect on ATPase activity of purified S1 and myofibrils. However, it completely suppressed the movement of actin filaments in in vitro motility assays and reduced active shortening of sarcomeres of skinned cardiac myocytes by half. Suppression of motion by the antihinge antibody may reflect a mechanical constraint imposed by the antibody upon the mobility of the S2 region of myosin. The results suggest that the steps in the mechanochemical energy transduction can be separately influenced through S2.

  3. Geographical patterns in cyanobacteria distribution: climate influence at regional scale.

    PubMed

    Pitois, Frédéric; Thoraval, Isabelle; Baurès, Estelle; Thomas, Olivier

    2014-01-28

    Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies.

  4. Geographical Patterns in Cyanobacteria Distribution: Climate Influence at Regional Scale

    PubMed Central

    Pitois, Frédéric; Thoraval, Isabelle; Baurès, Estelle; Thomas, Olivier

    2014-01-01

    Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies. PMID:24476711

  5. Influence of the cardiac myosin hinge region on contractile activity.

    PubMed

    Margossian, S S; Krueger, J W; Sellers, J R; Cuda, G; Caulfield, J B; Norton, P; Slayter, H S

    1991-06-01

    The participation of cardiac myosin hinge in contractility was investigated by in vitro motility and ATPase assays and by measurements of sarcomere shortening. The effect on contractile activity was analyzed using an antibody directed against a 20-amino acid peptide within the hinge region of myosin. This antibody bound specifically at the hinge at a distance of 55 nm from the S1/S2 junction, was specific to human, dog, and rat cardiac myosins, did not crossreact with gizzard or skeletal myosin, and had no effect on ATPase activity of purified S1 and myofibrils. However, it completely suppressed the movement of actin filaments in in vitro motility assays and reduced active shortening of sarcomeres of skinned cardiac myocytes by half. Suppression of motion by the anti-hinge antibody may reflect a mechanical constraint imposed by the antibody upon the mobility of the S2 region of myosin. The results suggest that the steps in the mechanochemical energy transduction can be separately influenced through S2.

  6. Influence of thermal deformations of resonators on propagation properties of laser annular beams through turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Peng, Yufeng; Peng, Fang; Han, Junpeng

    2013-02-01

    Based on the laser field from a positive confocal unstable resonator, considering the influence of thermal distortion of the internal resonator mirror on the annular beam, the propagation characteristics of the annular beam through turbulent atmosphere are investigated by means of the fast Fourier transform algorithm (FFT). The intensity distributions of the output laser far-field are obtained to analyze the propagation characteristics of laser annular beam through the turbulent atmosphere, which is a function about different propagation distances. The results show that the peak intensity of the laser pattern becomes depressed and the spread of the far field diagram patterns is broadened under the increasing of the transmission distance and the thermal distortion of the laser resonator. β-parameter and strehl ratio are introduced to estimate the annular beam quality characteristics. It is found that the annular beam through strong turbulence influences much less obviously than the annular beam through weak turbulence on the quality characteristics with thermal distortion. In the same atmospheric conditions with a certain distance, the greater the mirror thermal distortion is, the worse the annular beam quality characteristics is.

  7. THE INFLUENCE OF ATMOSPHERIC SCATTERING AND ABSORPTION ON OHMIC DISSIPATION IN HOT JUPITERS

    SciTech Connect

    Heng, Kevin

    2012-03-20

    Using semi-analytical, one-dimensional models, we elucidate the influence of scattering and absorption on the degree of Ohmic dissipation in hot Jovian atmospheres. With the assumption of Saha equilibrium, the variation in temperature is the main driver of the variations in the electrical conductivity, induced current, and Ohmic power dissipated. Atmospheres possessing temperature inversions tend to dissipate most of the Ohmic power superficially, at high altitudes, whereas those without temperature inversions are capable of greater dissipation deeper down. Scattering in the optical range of wavelengths tends to cool the lower atmosphere, thus reducing the degree of dissipation at depth. Purely absorbing cloud decks (in the infrared), of a finite extent in height, allow for localized reductions in dissipation and may reverse a temperature inversion if they are dense and thick enough, thus greatly enhancing the dissipation at depth. If Ohmic dissipation is the mechanism for inflating hot Jupiters, then variations in the atmospheric opacity (which may be interpreted as arising from variations in metallicity and cloud/haze properties) and magnetic field strength naturally produce a scatter in the measured radii at a given strength of irradiation. Future work will determine if these effects are dominant over evolutionary effects, which also contribute a scatter to the measured radii.

  8. Influence of non-Kolmogorov atmospheric turbulence on the beam quality of vortex beams.

    PubMed

    Li, Jinhong; Wang, Weiwei; Duan, Meiling; Wei, Jinlin

    2016-09-01

    Based on the extended Huygens-Fresnel principle and the definition of second-order moments of the Wigner distribution function (WDF), the analytical expressions for the propagation factors (M2-factors) and Strehl ratio SR of the Gaussian Schell-model (GSM) vortex beams and GSM non-vortex beams propagation through non-Kolmogorov atmospheric turbulence are derived, and used to study the influence of non-Kolmogorov atmospheric turbulence on beam quality of the GSM vortex beams. It is shown that the smaller the generalized structure constant and the outer scale of turbulence are, and the bigger the inner scale of turbulence is, the smaller the normalized propagation factor is, the bigger the Strehl ratio is, and the better the beam quality of GSM vortex beams in atmospheric turbulence is. The variation of beam quality with the generalized exponent α is nonmonotonic, when α = 3.11, the beam quality of the GSM vortex beams is the poorest through non-Kolmogorov atmospheric turbulence. GSM vortex beams is less affected by turbulence than GSM non-vortex beams under certain condition, and will be useful in long-distance free-space optical communications.

  9. Influence of non-Kolmogorov atmospheric turbulence on the beam quality of vortex beams.

    PubMed

    Li, Jinhong; Wang, Weiwei; Duan, Meiling; Wei, Jinlin

    2016-09-01

    Based on the extended Huygens-Fresnel principle and the definition of second-order moments of the Wigner distribution function (WDF), the analytical expressions for the propagation factors (M2-factors) and Strehl ratio SR of the Gaussian Schell-model (GSM) vortex beams and GSM non-vortex beams propagation through non-Kolmogorov atmospheric turbulence are derived, and used to study the influence of non-Kolmogorov atmospheric turbulence on beam quality of the GSM vortex beams. It is shown that the smaller the generalized structure constant and the outer scale of turbulence are, and the bigger the inner scale of turbulence is, the smaller the normalized propagation factor is, the bigger the Strehl ratio is, and the better the beam quality of GSM vortex beams in atmospheric turbulence is. The variation of beam quality with the generalized exponent α is nonmonotonic, when α = 3.11, the beam quality of the GSM vortex beams is the poorest through non-Kolmogorov atmospheric turbulence. GSM vortex beams is less affected by turbulence than GSM non-vortex beams under certain condition, and will be useful in long-distance free-space optical communications. PMID:27607647

  10. NO Detection by Pulsed Polarization of Lambda Probes–Influence of the Reference Atmosphere

    PubMed Central

    Fischer, Sabine; Schönauer-Kamin, Daniela; Pohle, Roland; Fleischer, Maximilian; Moos, Ralf

    2013-01-01

    The pulsed polarization measurement technique using conventional thimble type lambda probes is suitable for low ppm NOx detection in exhaust gas applications. To evaluate the underlying sensor mechanism, the unknown influence of the reference atmosphere on the NO sensing behavior is investigated in this study. Besides answering questions with respect to the underlying principle, this investigation can resolve the main question of whether a simplified sensor element without reference may be also suitable for NO sensing using the pulsed polarization measurement technique. With an adequate sensor setup, the reference atmosphere of the thimble type lambda probe is changed completely after a certain diffusion time. Thus, the sensor response regarding NO is compared with and without different gas atmospheres on both electrodes. It is shown that there is still a very good NO sensitivity even without reference air, although the NO response is reduced due to non-existing overlying mixed potential type voltage, which is otherwise caused by different atmospheres on both electrodes. Considering these results, we see an opportunity to simplify the standard NOx sensor design by omitting the reference electrode.

  11. Influence of atmospheric energy transport on amplification of winter warming in the Arctic

    NASA Astrophysics Data System (ADS)

    Alekseev, Genrikh; Kuzmina, Svetlana; Urazgildeeva, Aleksandra; Bobylev, Leonid

    2016-04-01

    The study was performed on base reanalysis ERA/Interim to discover the link between amplified warming in the high Arctic and the atmospheric transport of heat and water vapor through the 70 ° N. The partitioning transports across the Atlantic and Pacific "gates" is established the link between variations of atmospheric flux through the "gates" and a larger part of the variability of the average surface air temperature, water vapor content and its trends in the winter 1980-2014. Influence of winter (December-February) atmospheric transport across the Atlantic "gate" at the 1000 hPa on variability of average for January-February surface air temperature to north 70° N is estimated correlation coefficient 0.75 and contribution to the temperature trend 40%. These results for the first time denote the leading role of increasing atmospheric transport on the amplification of winter warming in the high Arctic. The investigation is supported with RFBR project 15-05-03512.

  12. On how climate variability influences regional sea level change

    NASA Astrophysics Data System (ADS)

    Brunnabend, Sandra-Esther; Kusche, Jürgen; Rietbroek, Roelof; Forootan, Ehsan

    2016-04-01

    Regional trends in sea level change are strongly influenced by climate variations, such as ENSO (El-Nino Southern Oscillation), the IOD (Indian Ocean Dipole), or the PDO (Pacific Decadal Oscillation). Hence, before computing long term regional sea level change, these sea level variations need to be taken into account as they lead to strong dependencies of computed regional sea level trends on the time period of the investigation. In this study, sea level change during the years 1993 to 2013 is analysed to identify the dominant modes of sea level change caused by climate variations. Here, two different gridded altimetry products are analysed, namely ESA's combined CCI SeaLevel v1.1 ECV product (doi: 10.5270/esa-sea_level_cci-1993_2013-v_1.1-201412), and absolute dynamic topography produced by Ssalto/Duacs and distributed by Aviso, with support from Cnes (http://www.aviso.altimetry.fr/duacs/). Reconstructions using the different decomposition techniques including the standard principle component analysis (PCA), rotated empirical orthogonal functions (REOF) and independent component analysis (ICA) method are analysed. They are compared with sea level change modelled with the global finite-element sea-ice ocean model (FESOM). The results indicate that from the applied methods, ICA is most suitable to separate the individual climate variability signals in independent modes of sea level change. This especially holds for extracting the ENSO contribution in sea level changes, which was better separated by applying ICA, from both altimetry and modelled sea level products. In addition, it is presented how modelled sea level change reflects climate variations compared to that identified in the altimetry products.

  13. Decadal trends of ocean and land carbon fluxes from a regional joint ocean-atmosphere inversion

    NASA Astrophysics Data System (ADS)

    Steinkamp, K.; Gruber, N.

    2015-12-01

    From 1980 until 2010, the combined CO2 sink strengths of ocean and land increased by nearly 50% (-0.55 Pg C yr-1 decade-1), but the spatial distribution of this trend is not well known. We address this by performing a joint cyclostationary ocean-atmosphere inversion for the three decades 1980-1989, 1990-1999, and 2000-2008, using only carbon data from the ocean and atmosphere as constraints, i.e., without applying any prior information about the land fluxes. We find that in the inversion, most of the 30 year sink trend stems from the ocean (-0.44 Pg C yr-1 decade-1). The contribution of the terrestrial biosphere is commensurably smaller but has more decadal variability. First, the land sink strength intensified in the 1990s by 0.4 (±0.3) Pg C yr-1 compared to the 1980s but then weakened slightly by 0.2 (±0.4) Pg C yr-1 in the 2000s. The different land regions contributed very variedly to these global trends. While the northern extratropical land acted as an increasing carbon sink throughout the examined period primarily driven by boreal regions, the tropical land is estimated to have acted as an increasing source of CO2, with source magnitude and trend dominated by enhanced release in tropical America during the Amazon mean wet season. This pattern is largely unchanged if the oceanic inversion constraint, which is based on a stationary ocean circulation, is replaced by an estimate based on simulation results from an ocean biogeochemical general circulation model that includes year-to-year variability in the air-sea CO2 fluxes and also has a trend (-0.07 Pg C yr-1 decade-1) that is at the very low end of current estimates. However, the land/ocean partitioning of the trend contribution is adjusted accordingly. Oceanic carbon data has a major impact on carbon exchange for all tropical regions and southern Africa but also for observationally better constrained regions in North America and temperate Asia. The European trend exhibits a strong sensitivity to the choice

  14. Data Assimilation and Regional Forecasts Using Atmospheric InfraRed Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley; Jedlovec, Gary

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses, which in turn should lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with an accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to optimally assimilate AIRS thermodynamic profiles--obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm-into a regional configuration of the Weather Research and Forecasting (WRF) model using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background field type, a methodology for ingesting AIRS profiles as separate over-land and over-water retrievals with different error characteristics, and utilization of level-by-level quality indicators to select only the highest quality data. The assessment of the impact of the AIRS profiles on WRF-Var analyses will focus on intelligent use of the quality indicators, optimized tuning of the WRF-Var, and comparison of analysis soundings to radiosondes. The analyses will be used to conduct a month-long series of regional forecasts over the continental U.S. The long-tern1 impact of AIRS profiles on forecast will be assessed against verifying radiosonde and stage IV precipitation data.

  15. Atmospheric Transport of Arid Aerosol from Desert Regions of Central Asia

    NASA Astrophysics Data System (ADS)

    Chen, Boris; Solomon, Paul; Sitnov, Sergei; Grechko, Evgeny; Maximenkov, Leonid; Artamonova, Maria; Pogarski, Fedor

    2010-05-01

    Investigation of atmospheric transport of arid aerosol from Central Asia was held within the ISTC project 3715. Particular attention was paid to the removal of aerosol from the Aral Sea region and its further transport, because aerosol and pollutants emission from Central Asia affect the airspace of the entire Asian continent. At the same time measurements of aerosols in the atmosphere of Central Asia are holding in a small number of stations, and currently available data are insufficient to define the initial conditions and/or verification of models of long-range transport. To identify sources of pollution transported from Central Asia, in Kyrgyzstan measurement and sampling of air were organized: at the station on the northern slope of the Kirgiz Range, 30 km south of Bishkek, at an altitude of 1700 m above sea level (Bishkek Site, 42,683N; 74,694E ), and on permanent alpine Teploklyuchenka lidar station in the Central Tien Shan at an altitude of 2000 m above sea level (Lidar Site, 42,467N; 78,533E). The chemical analysis of collected aerosol and soils samples was carried out. Measurements of aerosol at these stations have been merged with the simulation of the trajectories of air masses in the study region and with the satellite (the Terra and Aqua satellites) observations of aerosol optical thickness in this region. Satellite data for the region 43-47 N, and 58-62 E (Aral Sea) from April 2008 to September 2009 were analyzed. The moments were selected, when the value of aerosol optical thickness (AOT) was greatest (more than 0.5), and the transport from the Aral Sea region to the observation sites took place. For each of these days, the forward trajectories, which started at 6 points within the region, were calculated using the HYSPLIT model. The days, on which the trajectories reached the BISHKEK and LIDAR sites, were determined from the data obtained. Calculations on the basis of the RAMS model were performed for these days. These calculations were performed

  16. Mercury emissions to the atmosphere from natural and anthropogenic sources in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Costa, P.; Pacyna, J. M.; Ferrara, R.

    This report discusses past, current and projected mercury emissions to the atmosphere from major industrial sources, and presents a first assessment of the contribution to the regional mercury budget from selected natural sources. Emissions (1995 estimates) from fossil fuels combustion (29.8 t yr -1) , cement production (28.8 t yr -1) and incineration of solid wastes (27.6 t yr -1) , all together account for about 82% of the regional anthropogenic total (105.7 t yr -1) . Other industrial sources in the region are smelters (4.8 t yr -1) , iron-steel plants (4.8 t yr -1) and other minor sources (chlor-alkali plants, crematoria, chemicals production) that have been considered together in the miscellaneous category (9.6 t yr -1) . Regional emissions from anthropogenic sources increased at a rate of 3% yr-1 from 1983 to 1995 and are projected to increase at a rate of 1.9% yr-1 in the next 25 years, if no improvement in emission control policy occurs. On a country-by-country basis, France is the leading emitter country with 22.6 t yr -1 followed by Turkey (16.1 t yr -1) , Italy (11.4 t yr -1) , Spain (9.1 t yr -1) , the former Yugoslavia 7.9 ( t yr -1) , Morocco (6.9 t yr -1) , Bulgaria (6.8 t yr -1) , Egypt (6.1 t yr -1) , Syria (3.6 t yr -1) , Libya (2.9 t yr -1) , Tunisia (2.8 t yr -1) and Greece (2.7 t yr -1) , whereas the remaining countries account for less than 7% of the regional total. The annual emission from natural sources is 110 t yr -1, although this figure only includes the volatilisation of elemental mercury from surface waters and emissions from volcanoes, whereas the contribution due to the degassing of mercury from top soil and vegetation has not been included in this first assessment. Therefore, natural and anthropogenic sources in the Mediterranean region release annually about 215 t of mercury, which represents a significant contribution to the total mercury budget released in Europe and to the global atmosphere.

  17. Morphology and Chemical composition of Atmospheric Particles over Semi-Arid region (Jaipur, Rajasthan) of India

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Agnihotri, R.; Yadav, P.; Singh, S.; Tawale, J. S.; Rashmi, R.; Prasad, M.; Arya, B. C.; Mishra, N.

    2012-12-01

    Uncertainties associated with the radiative forcing of atmospheric dust particles is highest, owing to lack of region-specific dust morphology (particle shape, size) and mineralogy (chemical composition) database, needed for modeling their optical properties (Mishra and Tripathi, 2008). To fill this gap for the Indian region, we collected atmospheric particles (with aerodynamic size <5um, PM5 and a few bulk particles; TSP) from seven sites of Jaipur and nearby locales (semi-arid region, in the vicinity of Thar Desert of Rajasthan) at varying altitude, during late winters of ca. 2012. PM5 particles were collected on Teflon filters (for bulk chemical analyses), while pure Tin substrates (~1×1 mm2) were used for investigating individual particle morphology. Using Scanning Electron Microscope equipped with Energy Dispersive X ray (SEM-EDX) facility at NPL, images of individual particles were recorded and the morphological parameters (e.g. Aspect ratio; AR, Circulatory parameter; CIR.) were retrieved following Okada et al. (2001), whereas chemical compositions of individual particles were determined by EDX and bulk samples by X ray fluorescence (XRF). The geometrical size distributions of atmospheric particles were generated for each site. Based on NIST (National Institute of Standard and Technology, USA) morphology database, the site-specific individual particle shapes reveal predominance of "Layered" (calcite and quartz rich), "Angular" structures (quartz rich) and "Flattened" particles over all the sites. Particles were found to be highly non-spherical with irregular shapes (CIR varying from 1 to 0.22 with median value ~0.76; AR varying from 1 to 5.4 with median value ~1.64). Noteworthy to mention, that unit values of AR and CIR represent spherical particles. Chemical analyses of PM5 particles revealed dominance of crustal elements e.g. Si, Al, Fe, Ca, Mg, in general. Particles over Kukas Hill (27.027° N, 75.919° E; ~800 MAGL) showed highest Fe mass fractions (~43

  18. Chemistry-turbulence interactions and mesoscale variability influence the cleansing efficiency of the atmosphere

    NASA Astrophysics Data System (ADS)

    Kaser, L.; Karl, T.; Yuan, B.; Mauldin, R. L.; Cantrell, C. A.; Guenther, A. B.; Patton, E. G.; Weinheimer, A. J.; Knote, C.; Orlando, J.; Emmons, L.; Apel, E.; Hornbrook, R.; Shertz, S.; Ullmann, K.; Hall, S.; Graus, M.; Gouw, J.; Zhou, X.; Ye, C.

    2015-12-01

    The hydroxyl radical (OH) is the most important oxidant in the atmosphere and the primary sink for isoprene, the dominant volatile organic compound emitted by vegetation. Recent research on the atmospheric oxidation capacity in isoprene-dominated environments has suggested missing radical sources leading to significant overestimation of the lifetime of isoprene. Here we report, for the first time, a comprehensive experimental budget of isoprene in the planetary boundary layer based on airborne flux measurements along with in situ OH observations in the Southeast and Central U.S. Our findings show that surface heterogeneity of isoprene emissions lead to a physical separation of isoprene and OH resulting in an effective slowdown in the chemistry. Depending on surface heterogeneity, the intensity of segregation (Is) could locally slow down isoprene chemistry up to 30%. The effect of segregated reactants in the planetary boundary layer on average has an influence on modeled OH radicals that is comparable to that of recently proposed radical recycling mechanisms.

  19. Premixed Atmosphere and Convection Influences on Flame Inhibition and Combustion (PACIFIC)

    NASA Technical Reports Server (NTRS)

    Ronney, Paul D.

    1995-01-01

    Under NASA-Lewis Grant NAG3-1611, starting date 6/1/94, a three-year experimental and theoretical study of the effects of ambient atmosphere on the properties of flame spread over thin and thick solid fuel beds has been initiated. In particular the effect of the type of inert gas, which affects the Lewis numbers of fuel and oxidant, and the effect of the addition of sub-flammability-limit concentrations of gaseous fuels to the oxidizing atmosphere will be studied. The effect of convection will be studied through one-g and mu g experiments with and without a forced flow. Moreover, the influence of thermal radiation, whose effect is known to be markedly different depending on the convection level, will be addressed.

  20. Advanced Modeling Techniques to Study Anthropogenic Influences on Atmospheric Chemical Budgets

    NASA Technical Reports Server (NTRS)

    Mathur, Rohit

    1997-01-01

    This research work is a collaborative effort between research groups at MCNC and the University of North Carolina at Chapel Hill. The overall objective of this research is to improve the level of understanding of the processes that determine the budgets of chemically and radiatively active compounds in the atmosphere through development and application of advanced methods for calculating the chemical change in atmospheric models. The research performed during the second year of this project focused on four major aspects: (1) The continued development and refinement of multiscale modeling techniques to address the issue of the disparate scales of the physico-chemical processes that govern the fate of atmospheric pollutants; (2) Development and application of analysis methods utilizing process and mass balance techniques to increase the interpretive powers of atmospheric models and to aid in complementary analysis of model predictions and observations; (3) Development of meteorological and emission inputs for initial application of the chemistry/transport model over the north Atlantic region; and, (4) The continued development and implementation of a totally new adaptive chemistry representation that changes the details of what is represented as the underlying conditions change.

  1. Atmospheric correction using near-infrared bands for satellite ocean color data processing in the turbid western Pacific region.

    PubMed

    Wang, Menghua; Shi, Wei; Jiang, Lide

    2012-01-16

    A regional near-infrared (NIR) ocean normalized water-leaving radiance (nL(w)(λ)) model is proposed for atmospheric correction for ocean color data processing in the western Pacific region, including the Bohai Sea, Yellow Sea, and East China Sea. Our motivation for this work is to derive ocean color products in the highly turbid western Pacific region using the Geostationary Ocean Color Imager (GOCI) onboard South Korean Communication, Ocean, and Meteorological Satellite (COMS). GOCI has eight spectral bands from 412 to 865 nm but does not have shortwave infrared (SWIR) bands that are needed for satellite ocean color remote sensing in the turbid ocean region. Based on a regional empirical relationship between the NIR nL(w)(λ) and diffuse attenuation coefficient at 490 nm (K(d)(490)), which is derived from the long-term measurements with the Moderate-resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite, an iterative scheme with the NIR-based atmospheric correction algorithm has been developed. Results from MODIS-Aqua measurements show that ocean color products in the region derived from the new proposed NIR-corrected atmospheric correction algorithm match well with those from the SWIR atmospheric correction algorithm. Thus, the proposed new atmospheric correction method provides an alternative for ocean color data processing for GOCI (and other ocean color satellite sensors without SWIR bands) in the turbid ocean regions of the Bohai Sea, Yellow Sea, and East China Sea, although the SWIR-based atmospheric correction approach is still much preferred. The proposed atmospheric correction methodology can also be applied to other turbid coastal regions.

  2. Radiative transfer in the earth's atmosphere and ocean: influence of ocean waves.

    PubMed

    Plass, G N; Kattawar, G W; Guinn, J A

    1975-08-01

    The radiance in the earth's atmosphere and ocean is calculated for a realistic model including an ocean surface with waves. Individual photons are followed in a Monte Carlo calculation. In the atmosphere, both Rayleigh scattering by the molecules and Mie scattering by the aerosols as well as molecular and aerosol absorption are taken into account. Similarly, in the ocean, both Rayleigh scattering by the water molecules and Mie scattering by the hydrosols as well as absorption by the water molecules and hydrosols are considered. Separate single-scattering functions are used which are calculated separately for the aerosols and the hydrosols from the Mie theory with appropriate and different size distributions in each case. The scattering angles are determined from the appropriate scattering function including the strong forwardscattering peak when there is aerosol or hydrosol scattering. Both the reflected and refracted rays, as well as the rays that undergo total internal reflection, are followed at the oceanc surface. The wave slope is chosen from the Cox-Munk distribution. Graphs show the influence of the waves on the upward radiance at the top of the atmosphere and just above the ocean surface and on the downward radiance just below the ocean surface as well as deeper within the ocean. The radiance changes are sufficient at the top of the atmosphere to determine the sea state from satellite measurements. Within the ocean the waves smooth out the abrupt transition that occurs at the edge of the allowed cone for radiation entering a calm ocean. The influence of the waves on the contrast between the sky and sea at the horizon is discussed. It is shown that the downward flux just below the surface increases with wind speed at all solar angles.

  3. Modeling the influence of atmospheric leading modes on the variability of the Arctic freshwater cycle

    NASA Astrophysics Data System (ADS)

    Niederdrenk, L.; Sein, D.; Mikolajewicz, U.

    2013-12-01

    Global general circulation models show remarkable differences in modeling the Arctic freshwater cycle. While they agree on the general sinks and sources of the freshwater budget, they differ largely in the magnitude of the mean values as well as in the variability of the freshwater terms. Regional models can better resolve the complex topography and small scale processes, but they are often uncoupled, thus missing the air-sea interaction. Additionally, regional models mostly use some kind of salinity restoring or flux correction, thus disturbing the freshwater budget. Our approach to investigate the Arctic hydrologic cycle and its variability is a regional atmosphere-ocean model setup, consisting of the global ocean model MPIOM with high resolution in the Arctic coupled to the regional atmosphere model REMO. The domain of the atmosphere model covers all catchment areas of the rivers draining into the Arctic. To account for all sinks and sources of freshwater in the Arctic, we include a discharge model providing terrestrial lateral waterflows. We run the model without salinity restoring but with freshwater correction, which is set to zero in the Arctic. This allows for the analysis of a closed freshwater budget in the Artic region. We perform experiments for the second half of the 20th century and use data from the global model MPIOM/ECHAM5 performed with historical conditions, that was used within the 4th Assessment Report of the IPCC, as forcing for our regional model. With this setup, we investigate how the dominant modes of large-scale atmospheric variability impact the variability in the freshwater components. We focus on the two leading empirical orthogonal functions of winter mean sea level pressure, as well as on the North Atlantic Oscillation and the Siberian High. These modes have a large impact on the Arctic Ocean circulation as well as on the solid and liquid export through Fram Strait and through the Canadian archipelago. However, they cannot explain

  4. Atmospheric pollutants and their influence on acidification of rain water at an industrial location on the West Coast OF India

    NASA Astrophysics Data System (ADS)

    Khemani, L. T.; Momin, G. A.; Rao, P. S. P.; Pillai, A. G.; Safai, P. D.; Mohan, K.; Rao, M. G.

    The chemical analysis of rain water samples at 11 locations along with measurements of atmospheric aerosols and their size distributions were made to study the influence of pollutants on acidification of rain water during the monsoon season of 1990 at Chembur-Trombay area, a highly industrialized belt in Bombay region located on the west coast of India. The concentrations of acid precursor gases, namely, SO 2 and NO, emanating from industries were low and their influence on acidification was limited to a few kilometer radius of their sources. Whereas, the deposition of ionic components (Na +, K +, Ca 2+, Mg 2+ and CI -) whose sources are natural (sea and soil) were uniformly distributed throughout the region as compared to those released from man-made sources. The high concentration of alkaline components, especially Ca 2+ from natural sources and NH 3 released from a fertilizer plant, were responsible for neutralising H + ion concentration generated from the acidic components (SO 42- and N0 3-). The variation from acidic (1970s) to alkaline (1990s) nature of rainwater in the area maybe due to the change in the use of fuel from coal to natural gas, which contains less sulphur and also, the pollution control measures taken by the industries.

  5. The puzzling chemical composition of GJ 436B'S atmosphere: Influence of tidal heating on the chemistry

    SciTech Connect

    Agúndez, Marcelino; Selsis, Franck; Venot, Olivia; Iro, Nicolas

    2014-02-01

    The dissipation of the tidal energy deposited on eccentric planets may induce a heating of the planet that affects its atmospheric thermal structure. Here we study the influence of tidal heating on the atmospheric composition of the eccentric (e = 0.16) 'hot Neptune' GJ 436b, for which inconclusive chemical abundances are retrieved from multiwavelength photometric observations carried out during primary transit and secondary eclipse. We build up a one-dimensional model of GJ 436b's atmosphere in the vertical direction and compute the pressure-temperature and molecular abundances profiles for various plausible internal temperatures of the planet (up to 560 K) and metallicities (from solar to 100 times solar), using a radiative-convective model and a chemical model which includes thermochemical kinetics, vertical mixing, and photochemistry. We find that the CO/CH{sub 4} abundance ratio increases with metallicity and tidal heating, and ranges from 1/20 to 1000 within the ranges of metallicity and internal temperature explored. Water vapor locks most of the oxygen and reaches a very high abundance, whatever the metallicity and internal temperature of the planet. The CO{sub 2}/H{sub 2}O abundance ratio increases dramatically with metallicity, and takes values between 10{sup –5}-10{sup –4} with solar elemental abundances and ∼0.1 for a metallicity 100 times solar. None of the atmospheric models based on solid physical and chemical grounds provide a fully satisfactory agreement with available observational data, although the comparison of calculated spectra and observations seems to point to models with a high metallicity and efficient tidal heating, in which high CO/CH{sub 4} abundance ratios and warm temperatures in the dayside atmosphere are favored.

  6. The Puzzling Chemical Composition of GJ 436b's Atmosphere: Influence of Tidal Heating on the Chemistry

    NASA Astrophysics Data System (ADS)

    Agúndez, Marcelino; Venot, Olivia; Selsis, Franck; Iro, Nicolas

    2014-02-01

    The dissipation of the tidal energy deposited on eccentric planets may induce a heating of the planet that affects its atmospheric thermal structure. Here we study the influence of tidal heating on the atmospheric composition of the eccentric (e = 0.16) "hot Neptune" GJ 436b, for which inconclusive chemical abundances are retrieved from multiwavelength photometric observations carried out during primary transit and secondary eclipse. We build up a one-dimensional model of GJ 436b's atmosphere in the vertical direction and compute the pressure-temperature and molecular abundances profiles for various plausible internal temperatures of the planet (up to 560 K) and metallicities (from solar to 100 times solar), using a radiative-convective model and a chemical model which includes thermochemical kinetics, vertical mixing, and photochemistry. We find that the CO/CH4 abundance ratio increases with metallicity and tidal heating, and ranges from 1/20 to 1000 within the ranges of metallicity and internal temperature explored. Water vapor locks most of the oxygen and reaches a very high abundance, whatever the metallicity and internal temperature of the planet. The CO2/H2O abundance ratio increases dramatically with metallicity, and takes values between 10-5-10-4 with solar elemental abundances and ~0.1 for a metallicity 100 times solar. None of the atmospheric models based on solid physical and chemical grounds provide a fully satisfactory agreement with available observational data, although the comparison of calculated spectra and observations seems to point to models with a high metallicity and efficient tidal heating, in which high CO/CH4 abundance ratios and warm temperatures in the dayside atmosphere are favored.

  7. Coupling atmospheric mercury isotope ratios and meteorology to identify sources of mercury impacting a coastal urban-industrial region near Pensacola, Florida, USA

    NASA Astrophysics Data System (ADS)

    Demers, Jason D.; Sherman, Laura S.; Blum, Joel D.; Marsik, Frank J.; Dvonch, J. Timothy

    2015-10-01

    Identifying the anthropogenic and natural sources of mercury (Hg) emissions contributing to atmospheric mercury on local, regional, and global scales continues to be a grand challenge. The relative importance of various direct anthropogenic emissions of mercury, in addition to natural geologic sources and reemission of previously released and deposited mercury, differs regionally and temporally. In this study, we used local-scale, mesoscale, and synoptic-scale meteorological analysis to couple the isotopic composition of ambient atmospheric mercury with potential sources of mercury contributing to a coastal urban-industrial setting near a coal-fired power plant in Pensacola, Florida, USA. We were able to broadly discern four influences on the isotopic composition of ambient atmospheric mercury impacting this coastal urban-industrial region: (1) local to regional urban-industrial anthropogenic emissions (mean δ202Hg = 0.44 ± 0.05‰, 1SD, n = 3), (2) marine-influenced sources derived from the Gulf of Mexico (mean δ202Hg = 0.77 ± 0.15‰, 1SD, n = 4), (3) continental sources associated with north-northwesterly flows from within the planetary boundary layer (mean δ202Hg = 0.65 ± 0.04‰, 1SD, n = 3), and (4) continental sources associated with north-northeasterly flows at higher altitudes (i.e., 2000 m above ground level; mean δ202Hg = 1.10 ± 0.21‰, 1SD, n = 8). Overall, these data, in conjunction with previous studies, suggest that the background global atmospheric mercury pool is characterized by moderately positive δ202Hg values; that urban-industrial emissions drive the isotopic composition of ambient atmospheric mercury toward lower δ202Hg values; and that air-surface exchange dynamics across vegetation and soils of terrestrial ecosystems drive the isotopic composition of ambient atmospheric mercury toward higher positive δ202Hg values. The data further suggest that mass-independent fractionation (MIF) of both even-mass- and odd-mass-number isotopes

  8. The National Science Foundation's Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR) Student Community

    NASA Astrophysics Data System (ADS)

    Sox, L.; Duly, T.; Emery, B.

    2014-12-01

    The National Science Foundation sponsors Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) Workshops, which have been held every summer, for the past 29 years. CEDAR Workshops are on the order of a week long and at various locations with the goal of being close to university campuses where CEDAR type scientific research is done. Although there is no formal student group within the CEDAR community, the workshops are very student-focused. Roughly half the Workshop participants are students. There are two Student Representatives on the CEDAR Science Steering Committee (CSSC), the group of scientists who organize the CEDAR Workshops. Each Student Representative is nominated by his or her peers, chosen by the CSSC and then serves a two year term. Each year, one of the Student Representatives is responsible for organizing and moderating a day-long session targeted for students, made up of tutorial talks, which aim to prepare both undergraduate and graduate students for the topics that will be discussed in the main CEDAR Workshop. The theme of this session changes every year. Past themes have included: upper atmospheric instrumentation, numerical modeling, atmospheric waves and tides, magnetosphere-ionosphere coupling, equatorial aeronomy and many others. Frequently, the Student Workshop has ended with a panel of post-docs, researchers and professors who discuss pressing questions from the students about the next steps they will take in their careers. As the present and past CSSC Student Representatives, we will recount a brief history of the CEDAR Workshops, our experiences serving on the CSSC and organizing the Student Workshop, a summary of the feedback we collected about the Student Workshops and what it's like to be student in the CEDAR community.

  9. Influence of atmospheric turbulence on OAM-based FSO system with use of realistic link model

    NASA Astrophysics Data System (ADS)

    Li, Ming; Yu, Zhongyuan; Cvijetic, Milorad

    2016-04-01

    We study the influence of atmospheric turbulence on OAM-based free-space optical (FSO) communication by using the Pump turbulence spectrum model which accurately characterizes the realistic FSO link. A comprehensive comparison is made between the Pump and Kolmogorov spectrum models with respect to the turbulence impact. The calculated results show that obtained turbulence-induced crosstalk is lower, which means that a higher channel capacity is projected when the realistic Pump spectrum is used instead of the Kolmogorov spectrum. We believe that our results prove that performance of practical OAM-based FSO is better than one predicted by using the original Kolmogorov turbulence model.

  10. Influence of GNSS Configuration and Map Interpolation Method on InSAR Atmospheric Phase Assessment

    NASA Astrophysics Data System (ADS)

    Simonetto, Elisabeth; Durand, Frederic; Morel, Laurent; El Hamri, Yassine; Froger, Jean-Luc; Nicolas, Joelle; Durand, Stephane; Polidori, Laurent

    2015-05-01

    Radar interferometry has proven to be a relevant technique in many application contexts. However, although the development of advanced processing, the interpretation of interferometric measurements is still disturbed by the presence of an atmospheric signal. In this work, we deal with the correction of interferograms using tropospheric delays measured from GNSS stations. We propose some experiments that enhance the influence of different factors in the processing of tropospheric maps. The results show that the interpolation strategy and the GNSS network geometry have a significant impact on the correction.

  11. Climatological simulations of ozone and atmospheric aerosols in the Greater Cairo region

    SciTech Connect

    Steiner, A. L.; Tawfik, A. B.; Shalaby, A.; Zakey, A. S.; Abdel Wahab, M. M.; Salah, Z.; Solmon, F.; Sillman, S.; Zaveri, Rahul A.

    2014-04-16

    An integrated chemistry-climate model (RegCM4-CHEM) simulates present-day climate, ozone and tropospheric aerosols over Egypt with a focus on Greater Cairo (GC) region. The densley populated GC region is known for its severe air quality issues driven by high levels of anthropogenic pollution in conjuction with natural sources such as dust and agricultural burning events. We find that current global emission inventories underestimate key pollutants such as nitrogen oxides and anthropogenic aerosol species. In the GC region, average-ground-based NO2 observations of 40-60 ppb are substantially higher than modeled estimates (5-10 ppb), likely due to model grid resolution, improper boundary layer representation, and poor emissions inventories. Observed ozone concentrations range from 35 ppb (winter) to 80 ppb (summer). The model reproduces the seasonal cycle fairly well, but modeled summer ozone is understimated by approximately 15 ppb and exhibits little interannual variability. For aerosols, springtime dust events dominate the seasonal aerosol cycle. The chemistry-climate model captures the springtime peak aerosol optical depth (AOD) of 0.7-1 but is slightly greater than satellite-derived AOD. Observed AOD decreases in the summer and increases again in the fall due to agricultural burning events in the Nile Delta, yet the model underestimates this fall observed AOD peak, as standard emissions inventories underestimate this burning and the resulting aerosol emissions. Our comparison of modeled gas and particulate phase atmospheric chemistry in the GC region indicates that improved emissions inventories of mobile sources and other anthropogenic activities are needed to improve air quality simulations in this region.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  13. The Influence of Atmospheric Modeling Errors on GRACE Estimates of Mass Loss in Greenland and Antarctica

    NASA Astrophysics Data System (ADS)

    Hardy, R. A.; Nerem, R. S.; Wiese, D. N.

    2015-12-01

    The Gravity Recovery and Climate Experiment (GRACE) has produced robust estimates of the contributions of the Greenland and Antarctic ice sheets to sea level rise. A limiting factor in these estimates is the background model (AOD1B) used to remove the atmospheric contribution to the gravity signal. We test the accuracy of this background model against in situ pressure measurements in Greenland and Antarctica and find significant evidence of drift in the model relative to the instruments. Furthermore, we find that the ECMWF Reanalysis (ERA) Interim product better agrees with the in situ data over Greenland and Antarctica. Relative to ERA, biases in atmospheric pressure mask additional trends over both ice sheets and a significant acceleration in mass loss over Antarctica. Agreement with in situ measurements affirms the viability of ERA-Interim for correcting Level 2 GRACE products over these regions.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Health risk assessment for residents exposed to atmospheric diesel exhaust particles in southern region of Taiwan

    NASA Astrophysics Data System (ADS)

    Chio, Chia-Pin; Liao, Chung-Min; Tsai, Ying-I.; Cheng, Man-Ting; Chou, Wei-Chun

    2014-03-01

    Evidence shows a strong association among air pollution, oxidative stress (OS), deoxyribonucleic acid (DNA) damage, and diseases. Recent studies indicated that the aging, human neurodegenerative diseases and cancers resulted from mitochondrial dysfunction and OS. The purpose of this study is to provide a probabilistic risk assessment model to quantify the atmospheric diesel exhaust particles (DEP)-induced pre-cancer biomarker response and cancer incidence risk for residents in south Taiwan. We conducted entirely monthly particulate matter sampling data at five sites in Kaohsiung of south Taiwan in the period 2002-2003. Three findings were found: (i) the DEP dose estimates and cancer risk quantification had heterogeneously spatiotemporal difference in south Taiwan, (ii) the pre-cancer DNA damage biomarker and cancer incidence estimates had a positive yet insignificant association, and (iii) all the estimates of cancer incidence in south Taiwan populations fell within and slight lower than the values from previous cancer epidemiological investigations. In this study, we successfully assessed the tumor incidence for residents posed by DEP exposure in south Taiwan compared with the epidemiological approach. Our approach provides a unique way for assessing human health risk for residences exposed to atmospheric DEP depending on specific combinations of local and regional conditions. Our work implicates the importance of incorporating both environmental and health risk impacts into models of air pollution exposure to guide adaptive mitigation strategies.

  16. Grassland/atmosphere response to changing climate: Coupling regional and local scales. Final report

    SciTech Connect

    Coughenour, M.B.; Kittel, T.G.F.; Pielke, R.A.; Eastman, J.

    1993-10-01

    The objectives of the study were: to evaluate the response of grassland ecosystems to atmospheric change at regional and site scales, and to develop multiscaled modeling systems to relate ecological and atmospheric models with different spatial and temporal resolutions. A menu-driven shell was developed to facilitate use of models at different temporal scales and to facilitate exchange information between models at different temporal scales. A detailed ecosystem model predicted that C{sub 3} temperate grasslands wig respond more strongly to elevated CO{sub 2} than temperate C{sub 4} grasslands in the short-term while a large positive N-PP response was predicted for a C{sub 4} Kenyan grassland. Long-term climate change scenarios produced either decreases or increases in Colorado plant productivity (NPP) depending on rainfall, but uniform increases in N-PP were predicted in Kenya. Elevated CO{sub 2} is likely to have little effect on ecosystem carbon storage in Colorado while it will increase carbon storage in Kenya. A synoptic climate classification processor (SCP) was developed to evaluate results of GCM climate sensitivity experiments. Roughly 80% agreement was achieved with manual classifications. Comparison of lx and 2xCO{sub 2} GCM Simulations revealed relatively small differences.

  17. Atmospheric CO2 source and sink patterns over the Indian region

    NASA Astrophysics Data System (ADS)

    Fadnavis, Suvarna; Kumar, K. Ravi; Tiwari, Yogesh K.; Pozzoli, Luca

    2016-02-01

    In this paper we examine CO2 emission hot spots and sink regions over India as identified from global model simulations during the period 2000-2009. CO2 emission hot spots overlap with locations of densely clustered thermal power plants, coal mines and other industrial and urban centres; CO2 sink regions coincide with the locations of dense forest. Fossil fuel CO2 emissions are compared with two bottom-up inventories: the Regional Emission inventories in ASia (REAS v1.11; 2000-2009) and the Emission Database for Global Atmospheric Research (EDGAR v4.2) (2000-2009). Estimated fossil fuel emissions over the hot spot region are ˜ 500-950 gC m-2 yr-1 as obtained from the global model simulation, EDGAR v4.2 and REAS v1.11 emission inventory. Simulated total fluxes show increasing trends, from 1.39 ± 1.01 % yr-1 (19.8 ± 1.9 TgC yr-1) to 6.7 ± 0.54 % yr-1 (97 ± 12 TgC yr-1) over the hot spot regions and decreasing trends of -0.95 ± 1.51 % yr-1 (-1 ± 2 TgC yr-1) to -5.7 ± 2.89 % yr-1 (-2.3 ± 2 TgC yr-1) over the sink regions. Model-simulated terrestrial ecosystem fluxes show decreasing trends (increasing CO2 uptake) over the sink regions. Decreasing trends in terrestrial ecosystem fluxes imply that forest cover is increasing, which is consistent with India State of Forest Report (2009). Fossil fuel emissions show statistically significant increasing trends in all the data sets considered in this study. Estimated trend in simulated total fluxes over the Indian region is ˜ 4.72 ± 2.25 % yr-1 (25.6 TgC yr-1) which is slightly higher than global growth rate ˜ 3.1 % yr-1 during 2000-2010.

  18. XAFS Measurements under Atmospheric Pressure in the Soft X-ray Region

    SciTech Connect

    Nakanishi, Koji; Ohta, Toshiaki; Yagi, Shinya

    2010-06-23

    We have developed a compact experimental set-up for X-ray absorption fine structure (XAFS) measurements in He at atmospheric pressure (AP) in the soft X-ray region and used it for Mg and Cl K-edge XAFS measurements of MgCl{sub 2} and MgCl{sub 2{center_dot}}6H{sub 2}O. The spectra of MgCl{sub 2{center_dot}}6H{sub 2}O measured in He at AP were significantly different from those measured in vacuum. This suggests the importance of performing soft X-ray XAFS experiments under AP to obtain reliable spectra from hydrated compounds.

  19. A preliminary analysis of atmospheric diffusion parameters in the coastal region

    SciTech Connect

    Shaojia Fan; Haiming Zhu; Xuelan Lin; Shuqin Ma

    1996-12-31

    Base on the data measured by three-axes propeller anemometers mounted on a 100m tower located in the coastal area of Guangdong, China at 10 and 75m levels and the statistical turbulence`s theory, the atmospheric diffusion parameters have been analyzed. The results indicate that, in the coastal region, the horizontal turbulence was controlled by large-scale eddies and the vertical turbulence was controlled by comparatively small-scale eddies. There is an obvious rapid change in the diffusion parameters when the sea and land breezes change their direction from sea to land and vice versa. The rapid change in lower layer is more obvious than in the upper layer.

  20. Lightning driven inner radiation belt energy deposition into the atmosphere: regional and global estimates

    NASA Astrophysics Data System (ADS)

    Rodger, C. J.; Clilverd, M. A.; Thomson, N. R.; Nunn, D.; Lichtenberger, J.

    2005-12-01

    In this study we examine energetic electron precipitation fluxes driven by lightning, in order to determine the global distribution of energy deposited into the middle atmosphere. Previous studies using lightning-driven precipitation burst rates have estimated losses from the inner radiation belts. In order to confirm the reliability of those rates and the validity of the conclusions drawn from those studies, we have analyzed New Zealand data to test our global understanding of troposphere to magnetosphere coupling. We examine about 10000h of AbsPAL recordings made from 17 April 2003 through to 26 June 2004, and analyze subionospheric very-low frequency (VLF) perturbations observed on transmissions from VLF transmitters in Hawaii (NPM) and western Australia (NWC). These observations are compared with those previously reported from the Antarctic Peninsula. The perturbation rates observed in the New Zealand data are consistent with those predicted from the global distribution of the lightning sources, once the different experimental configurations are taken into account. Using lightning current distributions rather than VLF perturbation observations we revise previous estimates of typical precipitation bursts at L~2.3 to a mean precipitation energy flux of ~1×10-3 ergs cm-2s-1. The precipitation of energetic electrons by these bursts in the range L=1.9-3.5 will lead to a mean rate of energy deposited into the atmosphere of 3×10-4 ergs cm-2min-1, spatially varying from a low of zero above some ocean regions to highs of ~3-6×10-3 ergs cm-2min-1 above North America and its conjugate region.

  1. Ambient concentrations of atmospheric ammonia, nitrogen dioxide and nitric acid in an intensive agricultural region

    NASA Astrophysics Data System (ADS)

    Zbieranowski, Antoni L.; Aherne, Julian

    2013-05-01

    The spatial and temporal distribution of ambient atmospheric gaseous reactive nitrogen (Nr) species concentrations (ammonia [NH3], nitrogen dioxide [NO2] and nitric acid [HNO3]) were measured at the field scale in an intensive agricultural region in southern Ontario, Canada. Atmospheric concentrations were measured with the Willems badge diffusive passive sampler (18 sites for NH3, 9 sites for NO2 and HNO3) for one year (April 2010-March 2011; under a two week measurement frequency) within a 15 km × 15 km area. Dry deposition was calculated using the inferential method and estimated across the entire study area. The spatial distribution of emission sources associated with agricultural activity resulted in high spatial variability in annual average ambient NH3 concentrations (<3->8 μg m-3 within a 2 km distance, coefficient of variation ˜50%) and estimated dry deposition (4-13 kg N ha-1 yr-1) between sample sites. In contrast, ambient concentrations and deposition of both NO2 (˜5.2->6.5 μg m-3; 1.0-1.5 kg N ha-1 yr-1) and HNO3 (0.6-0.7 μg m-3; 0.5-1 kg N ha-1 yr-1) had low variability (coefficient of variation <10%). The observed NH3 concentrations accounted for ˜70% of gaseous Nr dry deposition. High NH3 concentrations suggest that reduced nitrogen species (NHx) will continue to make up an increasing fraction of Nr deposition within intensive agricultural regions in southern Ontario under legislated nitrogen oxide emission reductions. Further, estimated total inorganic Nr deposition (15-28 kg N ha-1 yr-1) may lead to potential changes in soil processes, nutrient imbalance and altered composition of mycorrhiza and ground vegetation within adjacent semi-natural ecosystems (estimated at ˜10% of the study area).

  2. Regional assessment of atmospheric organic and black carbon in South Africa

    NASA Astrophysics Data System (ADS)

    Gideon van Zyl, Pieter; Maritz, Petra; Beukes, Johan Paul; Liousse, Cathy; Galy-Lacaux, Corinne; Castéra, Pierre; Venter, Andrew; Pienaar, Kobus

    2014-05-01

    At present limited data exists for atmospheric black carbon (BC) and organic carbon (OC) in South Africa. In this paper BC and OC concentrations were explored in terms of spatial and temporal patterns, mass fractions of BC and OC of the overall aerosol mass, as well as linked to possible sources. PM10 and PM2.5 samples were collected at five sampling sites in South Africa operated within the DEBITS IDAF network, i.e. Louis Trichardt, Skukuza, Vaal Triangle, Amersfoort and Botsalano, with MiniVol samplers. Samples were analysed with a Thermal/Optical Carbon analyser. OC were higher than BC concentrations at all sites in both size fractions. Most OC and BC were present in the PM2.5 fraction. OC/BC ratios reflected the location of the different DEBITS sites, with sites in or close to anthropogenic source regions having the lowest OC/BC ratios, while background sites had the highest OC/BC ratios. The OC mass fraction percentage varied between 1% and 24%, while the BC mass fraction ranged between 1 and 12 %. The highest OC mass fraction was found at Skukuza in the Kruger National Park, which was attributed to both natural sources and anthropogenic impacts from a dominant path of air mass movement from the anthropogenic industrial hub of South Africa. The highest mass fraction of BC was found at the Vaal Triangle situated within an region highly impacted by industry and household combustion for space heating and cooking. A relatively distinct seasonal pattern was observed, with higher OC and BC concentrations determined between May and October, which coincide with the dry season in the interior of South Africa. Positive correlations between OC and BC concentrations with the distance from back trajectories passing over veld fires were observed, indicating that veld fires contribute significantly to atmospheric OC and BC during the burning months.

  3. A fully coupled regional atmospheric numerical model for integrated air quality and weather forecasting.

    NASA Astrophysics Data System (ADS)

    Freitas, S. R.; Longo, K. M.; Marecal, V.; Pirre, M.; Gmai, T.

    2012-04-01

    A new numerical modelling tool devoted to local and regional studies of atmospheric chemistry from surface to the lower stratosphere designed for both operational and research purposes will be presented. This model is based on the limited-area model CATT-BRAMS (Coupled Aerosol-Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System, Freitas et al. 2009, Longo et al. 2010) which is a meteorological model (BRAMS) including transport processes of gaseous and aerosols (CATT model). BRAMS is a version of the RAMS model (Walko et al. 2000) adapted to better represent tropical and subtropical processes and several new features. CATT-BRAMS has been used operationally at CPTEC (Brazilian Center for Weather Prediction and Climate Studies) since 2003 providing coupled weather and air quality forecast. In the Chemistry-CATT-BRAMS (called hereafter CCATT-BRAMS) a chemical module is fully coupled to the meteorological/tracer transport model CATT-BRAMS. This module includes gaseous chemistry, photochemistry, scavenging and dry deposition. The CCATT-BRAMS model takes advantages of the BRAMS specific development for the tropics/subtropics and of the recent availability of preprocessing tools for chemical mechanisms and of fast codes for photolysis rates. Similarly to BRAMS this model is conceived to run for horizontal resolutions ranging from a few meters to more than a hundred kilometres depending on the chosen scientific objective. In the last decade CCATT-BRAMS has being broadly (or extensively) used for applications mainly over South America, with strong emphasis over the Amazonia area and the main South American megacities. An overview of the model development and main applications will be presented.

  4. The influence of Indian Ocean atmospheric circulation on Warm Pool hydroclimate during the Holocene epoch

    NASA Astrophysics Data System (ADS)

    Tierney, J. E.; Oppo, D. W.; Legrande, A. N.; Huang, Y.; Rosenthal, Y.; Linsley, B. K.

    2012-10-01

    Existing paleoclimate data suggest a complex evolution of hydroclimate within the Indo-Pacific Warm Pool (IPWP) during the Holocene epoch. Here we introduce a new leaf wax isotope record from Sulawesi, Indonesia and compare proxy water isotope data with ocean-atmosphere general circulation model (OAGCM) simulations to identify mechanisms influencing Holocene IPWP hydroclimate. Modeling simulations suggest that orbital forcing causes heterogenous changes in precipitation across the IPWP on a seasonal basis that may account for the differences in time-evolution of the proxy data at respective sites. Both the proxies and simulations suggest that precipitation variability during the September-November (SON) season is important for hydroclimate in Borneo. The preëminence of the SON season suggests that a seasonally lagged relationship between the Indian monsoon and Indian Ocean Walker circulation influences IPWP hydroclimatic variability during the Holocene.

  5. The Influence of Indian Ocean Atmospheric Circulation on Warm Pool Hydroclimate During the Holocene Epoch

    NASA Technical Reports Server (NTRS)

    Tierney, J.E.; Oppo, D. W.; LeGrande, A. N.; Huang, Y.; Rosenthal, Y.; Linsley, B. K.

    2012-01-01

    Existing paleoclimate data suggest a complex evolution of hydroclimate within the Indo-Pacific Warm Pool (IPWP) during the Holocene epoch. Here we introduce a new leaf wax isotope record from Sulawesi, Indonesia and compare proxy water isotope data with ocean-atmosphere general circulation model (OAGCM) simulations to identify mechanisms influencing Holocene IPWP hydroclimate. Modeling simulations suggest that orbital forcing causes heterogenous changes in precipitation across the IPWP on a seasonal basis that may account for the differences in time-evolution of the proxy data at respective sites. Both the proxies and simulations suggest that precipitation variability during the September-November (SON) season is important for hydroclimate in Borneo. The preeminence of the SON season suggests that a seasonally lagged relationship between the Indian monsoon and Indian Ocean Walker circulation influences IPWP hydroclimatic variability during the Holocene.

  6. Characterization of atmospheric aerosols in the Po valley during the supersito campaigns - Part 3: Contribution of wood combustion to wintertime atmospheric aerosols in Emilia Romagna region (Northern Italy)

    NASA Astrophysics Data System (ADS)

    Pietrogrande, Maria Chiara; Bacco, Dimitri; Ferrari, Silvia; Kaipainen, Jussi; Ricciardelli, Isabella; Riekkola, Marja-Liisa; Trentini, Arianna; Visentin, Marco

    2015-12-01

    This paper investigates the influence of wood combustion on PM in fall/winter that are the most favorable seasonal periods with presumed intense biomass burning for residential heating due to low temperatures. As a part of the Supersito project, nearly 650 PM2.5 samples were daily collected at urban and rural sites in Emilia Romagna (Northern Italy) in five intensive experimental campaigns throughout the years from 2011 to 2014. From specific compounds related to wood combustion a set of 58 organic compounds was determined, such as anhydrosugars, primary biological sugars, low-molecular-weight carboxylic acids, methoxylated phenols, PAHs and carbonaceous components (EC/OC). Levoglucosan was by far the most dominant anhydrosugar, both on a relative and an absolute basis (35-1043 ng m-3), followed by mannosan (7-121 ng m-3) and galactosan (4-52 ng m-3), indicating that wood burning for domestic heating is a diffuse regional source during the seasons studied. Different diagnostic ratios between anhydrosugars and methoxylated phenols were computed to discriminate the prevalent contribution of hardwood as combustion fuel. The investigated 19 high molecular weight PAHs were more abundant at the urban than at the rural site, with mean total value of 4.3 and 3.2 ng m-3 at MS and SP, respectively. The strong contribution of wood combustion to atmospheric PAHs was indicated by the positive correlation between levoglucosan and the most abundant PAHs (R2 = 0.71÷0.79) and individually with benzo(a)pyrene (R2 = 0.79). By using this correlation, it was estimated that wood burning contributed nearly 77% to BaP concentration in the winter months. Based on the ratio between levoglucosan and OC data, it could be concluded that the wood burning contributed about 35% to OC during the cold November-February periods and the contribution was similar at both sampling sites.

  7. Surface pretreatment of plastics with an atmospheric pressure plasma jet - Influence of generator power and kinematics

    SciTech Connect

    Moritzer, E. Leister, C.

    2014-05-15

    The industrial use of atmospheric pressure plasmas in the plastics processing industry has increased significantly in recent years. Users of this treatment process have the possibility to influence the target values (e.g. bond strength or surface energy) with the help of kinematic and electrical parameters. Until now, systematic procedures have been used with which the parameters can be adapted to the process or product requirements but only by very time-consuming methods. For this reason, the relationship between influencing values and target values will be examined based on the example of a pretreatment in the bonding process with the help of statistical experimental design. Because of the large number of parameters involved, the analysis is restricted to the kinematic and electrical parameters. In the experimental tests, the following factors are taken as parameters: gap between nozzle and substrate, treatment velocity (kinematic data), voltage and duty cycle (electrical data). The statistical evaluation shows significant relationships between the parameters and surface energy in the case of polypropylene. An increase in the voltage and duty cycle increases the polar proportion of the surface energy, while a larger gap and higher velocity leads to lower energy levels. The bond strength of the overlapping bond is also significantly influenced by the voltage, velocity and gap. The direction of their effects is identical with those of the surface energy. In addition to the kinematic influences of the motion of an atmospheric pressure plasma jet, it is therefore especially important that the parameters for the plasma production are taken into account when designing the pretreatment processes.

  8. Influence of land-atmosphere feedbacks on temperature and precipitation extremes in the GLACE-CMIP5 ensemble

    NASA Astrophysics Data System (ADS)

    Lorenz, Ruth; Argüeso, Daniel; Donat, Markus G.; Pitman, Andrew J.; Hurk, Bart; Berg, Alexis; Lawrence, David M.; Chéruy, Frédérique; Ducharne, Agnès.; Hagemann, Stefan; Meier, Arndt; Milly, P. C. D.; Seneviratne, Sonia I.

    2016-01-01

    We examine how soil moisture variability and trends affect the simulation of temperature and precipitation extremes in six global climate models using the experimental protocol of the Global Land-Atmosphere Coupling Experiment of the Coupled Model Intercomparison Project, Phase 5 (GLACE-CMIP5). This protocol enables separate examinations of the influences of soil moisture variability and trends on the intensity, frequency, and duration of climate extremes by the end of the 21st century under a business-as-usual (Representative Concentration Pathway 8.5) emission scenario. Removing soil moisture variability significantly reduces temperature extremes over most continental surfaces, while wet precipitation extremes are enhanced in the tropics. Projected drying trends in soil moisture lead to increases in intensity, frequency, and duration of temperature extremes by the end of the 21st century. Wet precipitation extremes are decreased in the tropics with soil moisture trends in the simulations, while dry extremes are enhanced in some regions, in particular the Mediterranean and Australia. However, the ensemble results mask considerable differences in the soil moisture trends simulated by the six climate models. We find that the large differences between the models in soil moisture trends, which are related to an unknown combination of differences in atmospheric forcing (precipitation, net radiation), flux partitioning at the land surface, and how soil moisture is parameterized, imply considerable uncertainty in future changes in climate extremes.

  9. The Influence of the Several Very Large Solar Proton Events in Years 2000-2003 on the Neutral Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Sinnhuber, Miriam; Anderson, John; McPeters, Richard D.; FLeming, Eric L.; Russell, James M.

    2004-01-01

    Solar proton events (SPEs) are known to have caused changes in constituents in the Earth's neutral middle atmosphere. The highly energetic protons produce ionizations, excitations, dissociations, and dissociative ionizations of the background constituents, which lead to the production of HOx (H, OH, HO2) and NOy (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2). The HOx increases lead to short-lived ozone decreases in the mesosphere and upper stratosphere due to the short lifetimes of the HOx constituents. The NOy increases lead to long-lived stratospheric ozone changes because of the long lifetime of the NOy family in this region. The past four years, 2000-2003, have been replete with SPEs and huge fluxes of high energy protons occurred in July and November 2000, September and November 2001, April 2002, and October 2003. Smaller, but still substantial, proton fluxes impacted the Earth during other months from year 2000 to 2003. The Goddard Space Flight Center (GSFC) Two-dimensional (2D) Model was used in computing the influence of the SPEs. The impact of these extremely large SPEs was calculated to be especially large in the upper stratosphere and mesosphere. The results of the GSFC 2D Model will be shown along with comparisons to the Upper Atmosphere Research Satellite (UARS) Halogen Occultation Experiment (HALOE) and Solar Backscatter Ultraviolet 2 (SBUV/2) instruments.

  10. Bidirectional Spectral Reflectance of Earth Resources: Influence of Scene Complexity and Atmospheric Effects on Remote Sensing

    NASA Technical Reports Server (NTRS)

    Diner, D. J.

    1984-01-01

    Practical methods for remote sensing when scene complexity and atmospheric effects modify intrinsic reflective properties are developed. The radiation history from ground to space of light reflected from individual leaves is initially multiply scattered within the crop canopy, whose geometry provides a controlling influence, then scattered and attenuated as a result of transmission through the Earth's atmosphere. The experimental and theoretical tools for studying these effects quantitatively are under development. A new radiative transfer code which uses Fourier transforms to solve the 3-D equation of transfer was developed. The initial version permits inhomogeneous non-Lambertian surfaces but assumes horizontal uniformity for the atmosphere. The computational results are in excellent agreement with Monte Carlo calculations. Laboratory apparatus to study the variation of spectral reflectance of individual leaves as a function of illumination incidence angle and reflection angle was used. These data can then be used in models to determine canopy scattering effects. Stress tests by observing leaf reflectance at 0.9 microns as a function of time following clipping from the stem was performed. A reflectance increase due to loss of water has been observed.

  11. On transient events in the upper atmosphere generated away of thunderstorm regions

    NASA Astrophysics Data System (ADS)

    Morozenko, V.; Garipov, G.; Khrenov, B.; Klimov, P.; Panasyuk, M.; Sharakin, S.; Zotov, M.

    2011-12-01

    Experimental data on transient events in UV and Red-IR ranges obtained in the MSU missions "Unversitetsky-Tatiana" (wavelengths 300-400 nm) and "Unversitetsky-Tatiana-2" (wavelengths 300-400 nm and 600-800 nm), published by Garipov et al, in 2010 at COSPAR session http://www.cospar2010.org, at TEPA conference http://www.aragats.am/Conferences/tepa2010 and in 2011 by Sadovnichy et al, Solar System Research, 45, #1, 3-29 (2011); Vedenkin et al, JETP, v. 140, issue 3(9), 1-11 (2011) demonstrated existence of transients at large distances (up to thousands km) away of cloud thunderstorm regions. Those "remote" transients are short (1-5 msec) and are less luminous than the transients above thunderstorm regions. The ratio of Red-IR to UV photon numbers in those transients indicates high altitude of their origin (~70 km). Important observation facts are also: 1. a change of the exponent in transient distribution on luminosity Q ("-1" for photon numbers Q=1020 -1023 to "-2" for Q>1023), 2. a change of global distribution of transient with their luminosity (transients with Q>1023 are concentrated in equatorial range above continents, while transients with low luminosity are distributed more uniformly), 3. a phenomenon of transient sequences in one satellite orbit which is close to geomagnetic meridian. In the present paper phenomenological features of transients are explained in assumption that the observed transients have to be divided in two classes: 1. transients related to local, lower in the atmosphere, lightning at distance not more than hundreds km from satellite detector field of view in the atmosphere and 2. transients generated by far away lightning. Local transients are luminous and presumably are events called "transient luminous events" (TLE). In distribution on luminosity those events have some threshold Q~1023 and their differential luminosity distribution is approximated by power law exponent "-2". Remote transients have to be considered separately. Their

  12. OASIS: Ocean-Atmosphere-Sea-Ice-Snowpack Interactions in Polar Regions

    NASA Astrophysics Data System (ADS)

    Bottenheim, J. W.; Abbatt, J.; Beine, H.; Berg, T.; Bigg, K.; Domine, F.; Leck, C.; Lindberg, S.; Matrai, P.; MacDonald, R.; McConnell, J.; Platt, U.; Raspopov, O.; Shepson, P.; Shumilov, O.; Stutz, J.; Wolff, E.

    2004-05-01

    While Polar regions encompass a large part of the globe, little attention has been paid to the interactions between the atmosphere and its extensive snow-covered surfaces. Recent discoveries in the Arctic and Antarctic show that the top ten centimeters of snow is not simply a white blanket but in fact is a surprisingly reactive medium for chemical reactions in the troposphere. It has been concluded that interlinked physical, chemical, and biological mechanisms, fueled by the sun and occurring in the snow, are responsible for depletion of tropospheric ozone and gaseous mercury. At the same time production of highly reactive compounds (e.g. formaldehyde, nitrogen dioxide) has been observed at the snow surface. Air-snow interactions also have an impact on the chemical composition of the snow and hence the nature and amounts of material released in terrestrial/marine ecosystems during the melting of seasonal snow-packs. Many details of these possibly naturally occurring processes are yet to be discovered. For decades humans have added waste products including acidic particles (sulphates) and toxic contaminants such as gaseous mercury and POPs (persistent organic pollutants) to the otherwise pristine snow surface. Virtually nothing is known about transformations of these contaminants in the snowpack, making it impossible to assess the risk to the polar environment, including humans. This is especially disconcerting when considering that climate change will undoubtedly alter the nature of these transformations involving snow, ice, atmosphere, ocean, and, ultimately, biota. To address these topics an interdisciplinary group of scientists from North America, Europe and Japan is developing a set of coordinated research activities under the banner of the IGBP programs IGAC and SOLAS. The program of Ocean-Atmosphere-Sea Ice-Snowpack (OASIS) interactions has been established with a mission statement aimed at determining the impact of OASIS chemical exchange on tropospheric

  13. Simulating influence of QBO phase on planetary waves during a stratospheric warming in a general circulation model of the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Koval, Andrey; Gavrilov, Nikolai; Pogoreltsev, Alexander; Savenkova, Elena

    2016-04-01

    One of the important factors of dynamical interactions between the lower and upper atmosphere is energy and momentum transfer by atmospheric internal gravity waves. For numerical modeling of the general circulation and thermal regime of the middle and upper atmosphere, it is important to take into account accelerations of the mean flow and heating rates produced by dissipating internal waves. The quasi-biennial oscillations (QBOs) of the zonal mean flow at lower latitudes at stratospheric heights can affect the propagation conditions of planetary waves. We perform numerical simulation of global atmospheric circulation for the initial conditions corresponding to the years with westerly and easterly QBO phases. We focus on the changes in amplitudes of stationary planetary waves (SPWs) and traveling normal atmospheric modes (NAMs) in the atmosphere during SSW events for the different QBO phases. For these experiments, we use the global circulation of the middle and upper atmosphere model (MUAM). There is theory of PW waveguide describing atmospheric regions where the background wind and temperature allow the wave propagation. There were introduced the refractive index for PWs and found that strongest planetary wave propagation is in areas of large positive values of this index. Another important PW characteristic is the Eliassen-Palm flux (EP-flux). These characteristics are considered as useful tools for visualizing the PW propagation conditions. Sudden stratospheric warming (SSW) event has significant influence on the formation of the weather anomalous and climate changes in the troposphere. Also, SSW event may affect the dynamical and energy processes in the upper atmosphere. The major SSW events imply significant temperature rises (up to 30 - 40 K) at altitudes 30 - 50 km accompanying with corresponding decreases, or reversals, of climatological eastward zonal winds in the stratosphere.

  14. Assessing the influence of secondary organic aerosols on long-range atmospheric PAH transport

    NASA Astrophysics Data System (ADS)

    Friedman, C. L.; Selin, N. E.

    2013-12-01

    We incorporate recent experimental findings on the synergy between secondary organic aerosols (SOA) and polycyclic aromatic hydrocarbons (PAHs) in a global atmospheric chemical transport model to test the influence of different gas-particle partitioning parameterizations on long-range atmospheric transport of PAHs. PAHs, byproducts of organic combustion, are toxic compounds that have been measured in areas distant from sources, such as the Arctic. Historically, the transport of PAHs in the atmosphere has been modeled by assuming that PAHs instantaneously and reversibly equilibrate between the gas phase and a particulate phase, with observed particulate fractions often times exceeding model results for unknown reasons. Recently obtained laboratory-based findings suggest PAHs become trapped in SOA particles during SOA formation and are thus prevented from evaporation and/or oxidation, possibly explaining discrepancies between observed and modeled particulate fractions. Here, we use the global atmospheric chemical transport model GEOS-Chem to investigate whether incorporation of pyrene, a four-ring PAH, into SOA upon formation better represents atmospheric long-range transport and gas-particle speciation of PAHs compared to our default partitioning scheme, in which PAHs instantaneously equilibrate between the gas phase, primary organic carbon aerosols (OC), and black carbon aerosols (BC). In general, we find that BC plays an important role in pyrene transport and gas-particle partitioning, with a model that includes BC producing the best match to observed seasonal variation and magnitude of pyrene particulate fraction. Incorporation of 100% of pyrene into SOA upon emission with fractional evaporation thereafter results in a reasonable match to observed total pyrene concentrations in the northern hemisphere mid-latitudes, but severely overestimates particulate fraction. Assuming that pyrene partitions to SOA following an octanol-air equilibrium partition coefficient

  15. Atmospheric deposition of mercury and methylmercury to landscapes and waterbodies of the Athabasca oil sands region.

    PubMed

    Kirk, Jane L; Muir, Derek C G; Gleason, Amber; Wang, Xiaowa; Lawson, Greg; Frank, Richard A; Lehnherr, Igor; Wrona, Fred

    2014-07-01

    Atmospheric deposition of metals originating from a variety of sources, including bitumen upgrading facilities and blowing dusts from landscape disturbances, is of concern in the Athabasca oil sands region of northern Alberta, Canada. Mercury (Hg) is of particular interest as methylmercury (MeHg), a neurotoxin which bioaccumulates through foodwebs, can reach levels in fish and wildlife that may pose health risks to human consumers. We used spring-time sampling of the accumulated snowpack at sites located varying distances from the major developments to estimate winter 2012 Hg loadings to a ∼20 000 km(2) area of the Athabasca oil sands region. Total Hg (THg; all forms of Hg in a sample) loads were predominantly particulate-bound (79 ± 12%) and increased with proximity to major developments, reaching up to 1000 ng m(-2). MeHg loads increased in a similar fashion, reaching up to 19 ng m(-2) and suggesting that oil sands developments are a direct source of MeHg to local landscapes and water bodies. Deposition maps, created by interpolation of measured Hg loads using geostatistical software, demonstrated that deposition resembled a bullseye pattern on the landscape, with areas of maximum THg and MeHg loadings located primarily between the Muskeg and Steepbank rivers. Snowpack concentrations of THg and MeHg were significantly correlated (r = 0.45-0.88, p < 0.01) with numerous parameters, including total suspended solids (TSS), metals known to be emitted in high quantities from the upgraders (vanadium, nickel, and zinc), and crustal elements (aluminum, iron, and lanthanum), which were also elevated in this region. Our results suggest that at snowmelt, a complex mixture of chemicals enters aquatic ecosystems that could impact biological communities of the oil sands region.

  16. Atmospheric deposition of mercury and methylmercury to landscapes and waterbodies of the Athabasca oil sands region.

    PubMed

    Kirk, Jane L; Muir, Derek C G; Gleason, Amber; Wang, Xiaowa; Lawson, Greg; Frank, Richard A; Lehnherr, Igor; Wrona, Fred

    2014-07-01

    Atmospheric deposition of metals originating from a variety of sources, including bitumen upgrading facilities and blowing dusts from landscape disturbances, is of concern in the Athabasca oil sands region of northern Alberta, Canada. Mercury (Hg) is of particular interest as methylmercury (MeHg), a neurotoxin which bioaccumulates through foodwebs, can reach levels in fish and wildlife that may pose health risks to human consumers. We used spring-time sampling of the accumulated snowpack at sites located varying distances from the major developments to estimate winter 2012 Hg loadings to a ∼20 000 km(2) area of the Athabasca oil sands region. Total Hg (THg; all forms of Hg in a sample) loads were predominantly particulate-bound (79 ± 12%) and increased with proximity to major developments, reaching up to 1000 ng m(-2). MeHg loads increased in a similar fashion, reaching up to 19 ng m(-2) and suggesting that oil sands developments are a direct source of MeHg to local landscapes and water bodies. Deposition maps, created by interpolation of measured Hg loads using geostatistical software, demonstrated that deposition resembled a bullseye pattern on the landscape, with areas of maximum THg and MeHg loadings located primarily between the Muskeg and Steepbank rivers. Snowpack concentrations of THg and MeHg were significantly correlated (r = 0.45-0.88, p < 0.01) with numerous parameters, including total suspended solids (TSS), metals known to be emitted in high quantities from the upgraders (vanadium, nickel, and zinc), and crustal elements (aluminum, iron, and lanthanum), which were also elevated in this region. Our results suggest that at snowmelt, a complex mixture of chemicals enters aquatic ecosystems that could impact biological communities of the oil sands region. PMID:24873895

  17. Influence of atmospheric relative humidity on ultraviolet flux and aerosol direct radiative forcing: Observation and simulation

    NASA Astrophysics Data System (ADS)

    Xia, Dong; Chen, Ling; Chen, Huizhong; Luo, Xuyu; Deng, Tao

    2016-08-01

    The atmospheric aerosols can absorb moisture from the environment due to their hydrophilicity and thus affect atmospheric radiation fluxes. In this article, the ultraviolet radiation and relative humidity (RH) data from ground observations and a radiative transfer model were used to examine the influence of RH on ultraviolet radiation flux and aerosol direct radiative forcing under the clear-sky conditions. The results show that RH has a significant influence on ultraviolet radiation because of aerosol hygroscopicity. The relationship between attenuation rate and RH can be fitted logarithmically and all of the R2 of the 4 sets of samples are high, i.e. 0.87, 0.96, 0.9, and 0.9, respectively. When the RH is 60%, 70%, 80% and 90%, the mean aerosol direct radiative forcing in ultraviolet is -4.22W m-2, -4.5W m-2, -4.82W m-2 and -5.4W m-2, respectively. For the selected polluted air samples the growth factor for computing aerosol direct radiative forcing in the ultraviolet for the RH of 80% varies from 1.19 to 1.53, with an average of 1.31.

  18. Elevated atmospheric carbon dioxide and leaf litter chemistry: Influences on microbial respiration and net nitrogen mineralization

    SciTech Connect

    Randlett, D.L.; Zak, D.R.; Pregitzer, K.S.; Curtis, P.S.

    1996-09-01

    Elevated atmospheric CO{sub 2} has the potential to influence rates of C and N cycling in terrestrial ecosystems by altering plant litter chemistry and slowing rates of organic matter decomposition. We tested the hypothesis that the chemistry of leaf litter produced at elevated CO{sub 2} would slow C and N transformations in soil. Soils were amended with Populus leaf produced under two levels of atmospheric CO{sub 2} (ambient and twice-ambient) and soil N availability (low and high). Kinetic parameters for microbial respiration and net N mineralization were determined on soil with and without litter during a 32-wk lab incubation. Product accumulation curves for CO{sub 2}-C and inorganic N were fit to a first order rate equation [y=A(1-e{sup -kt})] using nonlinear regression analyses. Although CO{sub 2} treatment affected soluble sugar concentration in leaf litter (ambient =120 g kg{sup -1}, elevated =130 g kg{sup -1}), it did not affect starch concentration or C/N ratio. Microbial respiration, microbial biomass, and leaf litter C/N ratio were affected by soil N availability but not by atmospheric CO{sub 2}. Net N mineralization was a linear function of time and was not significantly different for leaves grown at ambient (50 mg N kg{sup -1}) and elevated CO{sub 2} (35 mg N kg{sup -1}). Consequently, we found no evidence for the hypothesis that leaf litter produced at elevated atmospheric CO{sub 2} will dampen the rates of C and N cycling in soil. 35 refs., 1 fig., 4 tabs.

  19. Atmospheric aerosols local-regional discrimination for a semi-urban area in India

    NASA Astrophysics Data System (ADS)

    Hooda, R. K.; Hyvärinen, A.-P.; Vestenius, M.; Gilardoni, S.; Sharma, V. P.; Vignati, E.; Kulmala, M.; Lihavainen, H.

    2016-02-01

    In the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI), measurements were carried out with a sequential filter-based aerosol sampler and on-line instruments for aerosol composition and behaviour at Gual Pahari, close to New Delhi. In fine mode (PM2.5), the secondary organic carbon (SOC) to total organic carbon ratio was 46%. This indicated that condensation of SOC on fine size particles could occur rapidly which may be related to the growth of aerosols and the potential to the size of cloud condensation nuclei in the region. Source region discrimination was improved significantly through coupling conditional probability functions with receptor modelling, and validation through volume size distribution. The air masses from industrial and dense populated regions show a mix of local as well as regional emissions to fine mode aerosols. The back-trajectory analysis captured the long-range transport of sea-salt aerosols enriched with mineral dust. The surface wind directions identified the influence of local emission activities.

  20. Can Regional Ocean-Atmosphere Coupled Model Improve the Simulation of the Interannual Variability of Western North Pacific Summer Monsoon?

    NASA Astrophysics Data System (ADS)

    Zou, L.; Zhou, T.

    2012-12-01

    With the motivation to improve the simulation of interannual variability of western North Pacific summer monsoon (WNPSM), a flexible regional ocean-atmosphere-land system coupled model (FROALS) was developed through the OASIS3.0 coupler. The regionally coupled model is composed of a regional climate model RegCM3 as its atmospheric component, a global climate ocean model (LICOM) as its oceanic component. Impacts of local air-sea interaction on the simulation of interannual variability of WNPSM are investigated by performing regionally ocean-atmosphere coupled and uncoupled simulations, with focus on the El Niño decaying summer. Compared to uncoupled simulation, the regionally coupled simulation exhibits improvements in both the climatology and interannual variability of rainfall over WNP. In El Niño decaying summer, the WNP saw an anomalous anticyclone, less rainfall and enhanced subsidence, which led to an increase in downward shortwave radiation flux, and thereby a warmer SST anomalies. Thus the ocean appears as a slave to atmospheric forcing. But in the uncoupled simulation, the atmosphere is a slave to oceanic SST forcing, the warmer SST anomalies located over east of the Philippines unrealistically produce excessive rainfall. In the regionally coupled run, the un-realistic positive rainfall anomalies and the associated atmospheric circulations over east of the Philippines are significantly improved, highlighting the importance of air-sea coupling in the simulation of interannual variability of WNPSM. One limitation of the model is that the anomalous anticyclone over WNP is weaker than the observation in both the regionally coupled and uncoupled simulations. This is resulted from the weaker simulated climatological summer rainfall intensity over the monsoon trough.

  1. Influences of impedance matching network on pulse-modulated radio frequency atmospheric pressure glow discharges

    SciTech Connect

    Huo, W. G.; Xu, K.; Sun, B.; Ding, Z. F.

    2012-08-15

    Pulse-modulated RF atmospheric pressure glow discharges (APDGs) were investigated in recent years to reduce the thermal accumulation and extend the operation region of the stable alpha glow mode. Different pulse-modulated voltage and current waveforms were acquired in previous experiments, but no attention was paid to the interpretation. We investigated this issue and associated phenomenon via positive and negative feedback effects derived from varying the series capacitor in the inversely L-shaped matching network used in our pulse-modulated RF APGD source. The evolutions of pulse-modulated RF waveforms were found to be associated with the feedback region and the pulsed plasma absorbed RF power. In the positive feedback region, pulse-modulated RF APGDs are relatively stable. In the negative feedback region, wide spikes as well as undershoots occur in RF voltage and current waveforms and the plasma absorbed RF power. In case of a high RF power discharge with a low modulation frequency, the pulse-modulated RF APGD is extinguished and re-ignited due to the enhanced undershoot during the initial pulse phase. The pulse-modulated RF APGD can transit from positive to negative feedback region in a range of series capacitance. Experimental results are discussed by the aid of equivalent circuit, negative and positive feedback effects.

  2. Influence of Regional Climate Model spatial resolution on wind climates

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Barthelmie, R. J.; Nikulin, G.; Jones, C.

    2010-12-01

    Global and regional climate models are being run at increasingly fine horizontal and vertical resolution with the goal of increased skill. However, relatively few studies have quantified the change in modeled wind climates that derives from applying a Regional Climate Model (RCM) at varying resolutions, and the response to varying resolution may be highly non-linear since most models run in climate mode are hydrostatic. Thus, herein we examine the influence of grid-resolution on modelled wind speeds and gusts and derived extremes thereof over southern Scandinavia using output from the Rossby Centre (RCA3) RCM run at four different resolutions from 50 x 50 km to 6 x 6 km, and with two different vertical grid-spacings. Domain averaged fifty-year return period wind speeds and wind gusts derived using the method of moments approach to compute the Gumbel parameters, increase with resolution (Table 1), though the change is strongly mediated by the model grid-cell surface characteristics. Power spectra of the 3-hourly model time-step ‘instantaneous’ wind speeds and daily wind gusts at all four resolutions show clear peaks in the variance associated with bi-annual, annual, seasonal and synoptic frequencies. The variance associated with these peaks is enhanced with increased resolution, though not in a monotonic fashion, and is more marked in wind gusts than wind speeds. Relative to in situ observations, the model generally underestimates the variance, particularly associated with the synoptic time scale, even for the highest resolution simulations. There is some evidence to suggest that the change in the power spectra with horizontal resolution is less marked in the transition from 12.5 km to 6.25 km, than from 50 to 25 km, or 25 km to 12.5 km.Table 1. Domain averaged mean annual wind speed (U), 50-year return period extreme wind speed (U50yr) and wind gust (Gust50yr) (m/s) from the four RCA3 simulations at different resolution based on output from 1987-2008. The

  3. [In situ measurement of atmospheric HCFC-22 at the Shangdianzi GAW regional station].

    PubMed

    Yao, Bo; Zhou, Ling-xi; Zhang, Fang; Zhang, Xiao-chun; Xu, Lin; Zhang, Xiao-ling; Zhou, Huai-gang; Dong, Fan; Zhou, Li-yan

    2010-08-01

    An in situ GC-ECD monitoring system was established at the Shangdianzi GAW Regional station from April 2007 to March 2008, and the mixing ratio of atmospheric HCFC-22 was (278.1 +/- 113.6) x 10(-12) (mol/mol). A "R" statistical software was applied to the HCFC-22 time series to separate background and pollution data. The background HCFC-22 mixing ratio was (199.5 +/- 5.1) x 10(-12), close to northern hemisphere background level observed at Mace Head and Trinidad Head stations. The pollution HCFC-22 mixing ratio was (312.1 +/- 121.0) x 10(-12) due to anthropogenic emission from various regions and air mass transport. There was no significant seasonal variability of background data. However, pollution data was much higher in summer than that in winter, and elevated up to 100.9 x 10(-12) in July than in January attribute to seasonal emission characteristics. The mean HCFC-22 mixing ratio from southwest wind sector (327.3 x 10(-12)) was much higher than that of northeast sector (236.2 x 10(-12)). The W-WSW-SW wind sector has a positive contribution to the HCFC-22 level, while NNE-N-NE has a large negative contribution. PMID:21090288

  4. Enhanced atmospheric oxygen outflow on Earth and Mars driven by a corotating interaction region

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Fraenz, M.; Dubinin, E.; Woch, J.; Lühr, H.; Wan, W.; Zong, Q.-G.; Zhang, T. L.; Pu, Z. Y.; Fu, S. Y.; Barabash, S.; Lundin, R.; Dandouras, I.

    2012-03-01

    Solar wind controls nonthermal escape of planetary atmospheric volatiles, regardless of the strength of planetary magnetic fields. For both Earth with a strong dipole and Mars with weak remnant fields, the oxygen ion (O+) outflow has been separately found to be enhanced during corotating interaction region (CIR) passage. Here we compared the enhancements of O+ outflow on Earth and Mars driven by a CIR in January 2008, when Sun, Earth, and Mars were approximately aligned. The CIR propagation was recorded by STEREO, ACE, Cluster, and Mars Express (MEX). During the CIR passage, Cluster observed enhanced flux of upwelling oxygen ions above the Earth's polar region, while MEX detected an increased escape flux of oxygen ions in the Martian magnetosphere. We found that (1) under a solar wind dynamic pressure increase of 2-3 nPa, the rate of increase in Martian O+ outflow flux was 1 order higher than those on Earth; and (2) as a response to the same part of the CIR body, the rate of increase in Martian O+ outflow flux was on the same order as for Earth. The comparison results imply that the dipole effectively prevents coupling of solar wind kinetic energy to planetary ions, and the distance to the Sun is also crucially important for planetary volatile loss in our inner solar system.

  5. Seasonal and spatial variations of atmospheric trace elemental deposition in the Aliaga industrial region, Turkey

    NASA Astrophysics Data System (ADS)

    Kara, Melik; Dumanoglu, Yetkin; Altiok, Hasan; Elbir, Tolga; Odabasi, Mustafa; Bayram, Abdurrahman

    2014-11-01

    Atmospheric bulk deposition (wet + dry deposition) samples (n = 40) were collected concurrently at ten sites in four seasons between June 2009 and April 2010 in the Aliaga heavily industrialized region, Turkey, containing a number of significant air pollutant sources. Analyses of trace elements were carried out using inductively coupled plasma-mass spectrometry (ICP-MS). While there were significant differences in the particulate matter (PM) deposition fluxes among the sampling sites, seasonal variations were not statistically significant (Kruskal-Wallis test, p < 0.05). Both PM deposition and elemental fluxes were increased at the sampling sites in the vicinity of industrial activities. The crustal elements (i.e., Ca, Mg) and some anthropogenic elements (such as Fe, Zn, Mn, Pb, Cu, and Cr) were high, and the highest fluxes were mostly measured in summer and winter seasons. The enrichment factor (EF) and principal component analysis (PCA) was applied to the data to determine the possible sources in the study area. High EF values were obtained for the anthropogenic elements such as Ag, Cd, Zn, Pb, Cu and Sb. The possible sources were identified as anthropogenic sources (i.e., iron-steel production) (45.4%), crustal and re-suspended dust (27.1%), marine aerosol (7.9%), and coal and wood combustion (8.2%). Thus, the iron-steel production and its related activities were found to be the main pollutant sources for this region.

  6. Long-range atmospheric transport Beryllium-7 to region the Sea of Japan.

    PubMed

    Neroda, Andrey S; Goncharova, Anna A; Goryachev, Vladimir A; Mishukov, Vasily F; Shlyk, Natalia V

    2016-08-01

    Concentrations of cosmogenic beryllium-7((7)Be) and atmospheric aerosols were measured in the atmosphere of the coastal zone of Vladivostok in 2013-2014. The (7)Be concentrations ranged from 0.5 to 4.1 mBq/m(3), with the lowest values in summer and the highest in spring and autumn; the mean value was 2.2 mBq/m(3). Analysis of meteorological data in the synoptic scale showed an inverse correlation with wet deposition rates R = -0.55 (p = 0.0001) and H2O mixing ratio R = -0.49 (p = 0.0001) and a positive with an average maximum height of 120-h backward trajectories of air masses R = 0.65 (p = 0.0001). Angular cluster analysis showed the (7)Be concentration to be dependent on the north-western (R = 0.53, p = 0.001) and eastern winds (R = -0.7, p = 0.0001 for 2013 and R = -0.49, p = 0.002 for 2014). The multiple regression analysis identified five factors in (7)Be concentration: altitudes (b = 0.44), air temperature (b = 0.36), a portion of trajectories in the pacific (North-East direction) cluster (b = -0.32), aerosol concentrations (b = 0.28) and wet precipitation rates (b = -0.24). The model has a good correlation with the data (adjusted R(2) = 0.55). It was found that the direction and height of the air masses trajectories in the lower troposphere strongly influence the concentration of (7)Be.

  7. Long-range atmospheric transport Beryllium-7 to region the Sea of Japan.

    PubMed

    Neroda, Andrey S; Goncharova, Anna A; Goryachev, Vladimir A; Mishukov, Vasily F; Shlyk, Natalia V

    2016-08-01

    Concentrations of cosmogenic beryllium-7((7)Be) and atmospheric aerosols were measured in the atmosphere of the coastal zone of Vladivostok in 2013-2014. The (7)Be concentrations ranged from 0.5 to 4.1 mBq/m(3), with the lowest values in summer and the highest in spring and autumn; the mean value was 2.2 mBq/m(3). Analysis of meteorological data in the synoptic scale showed an inverse correlation with wet deposition rates R = -0.55 (p = 0.0001) and H2O mixing ratio R = -0.49 (p = 0.0001) and a positive with an average maximum height of 120-h backward trajectories of air masses R = 0.65 (p = 0.0001). Angular cluster analysis showed the (7)Be concentration to be dependent on the north-western (R = 0.53, p = 0.001) and eastern winds (R = -0.7, p = 0.0001 for 2013 and R = -0.49, p = 0.002 for 2014). The multiple regression analysis identified five factors in (7)Be concentration: altitudes (b = 0.44), air temperature (b = 0.36), a portion of trajectories in the pacific (North-East direction) cluster (b = -0.32), aerosol concentrations (b = 0.28) and wet precipitation rates (b = -0.24). The model has a good correlation with the data (adjusted R(2) = 0.55). It was found that the direction and height of the air masses trajectories in the lower troposphere strongly influence the concentration of (7)Be. PMID:27156169

  8. Model assessment of atmospheric pollution control schemes for critical emission regions

    NASA Astrophysics Data System (ADS)

    Zhai, Shixian; An, Xingqin; Liu, Zhao; Sun, Zhaobin; Hou, Qing

    2016-01-01

    In recent years, the atmospheric environment in portions of China has become significantly degraded and the need for emission controls has become urgent. Because more international events are being planned, it is important to implement air quality assurance targeted at significant events held over specific periods of time. This study sets Yanqihu (YQH), Beijing, the location of the 2014 Beijing APEC (Asia-Pacific Economic Cooperation) summit, as the target region. By using the atmospheric inversion model FLEXPART, we determined the sensitive source zones that had the greatest impact on the air quality of the YQH region in November 2012. We then used the air-quality model Models-3/CMAQ and a high-resolution emissions inventory of the Beijing-Tianjian-Hebei region to establish emission reduction tests for the entire source area and for specific sensitive source zones. This was achieved by initiating emission reduction schemes at different ratios and different times. The results showed that initiating a moderate reduction of emissions days prior to a potential event is more beneficial to the air quality of Beijing than initiating a high-strength reduction campaign on the day of the event. The sensitive source zone of Beijing (BJ-Sens) accounts for 54.2% of the total source area of Beijing (BJ), but its reduction effect reaches 89%-100% of the total area, with a reduction efficiency 1.6-1.9 times greater than that of the entire area. The sensitive source zone of Huabei (HuaB-Sens.) only represents 17.6% of the total area of Huabei (HuaB), but its emission reduction effect reaches 59%-97% of the entire area, with a reduction efficiency 4.2-5.5 times greater than that of the total area. The earlier that emission reduction measures are implemented, the greater the effect they have on preventing the transmission of pollutants. In addition, expanding the controlling areas to sensitive provinces and cities around Beijing (HuaB-sens) can significantly accelerate the reduction

  9. Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism

    NASA Astrophysics Data System (ADS)

    Toon, O. B.; Turco, R. P.; Robock, A.; Bardeen, C.; Oman, L.; Stenchikov, G. L.

    2007-04-01

    We assess the potential damage and smoke production associated with the detonation of small nuclear weapons in modern megacities. While the number of nuclear warheads in the world has fallen by about a factor of three since its peak in 1986, the number of nuclear weapons states is increasing and the potential exists for numerous regional nuclear arms races. Eight countries are known to have nuclear weapons, 2 are constructing them, and an additional 32 nations already have the fissile material needed to build substantial arsenals of low-yield (Hiroshima-sized) explosives. Population and economic activity worldwide are congregated to an increasing extent in megacities, which might be targeted in a nuclear conflict. We find that low yield weapons, which new nuclear powers are likely to construct, can produce 100 times as many fatalities and 100 times as much smoke from fires per kt yield as previously estimated in analyses for full scale nuclear wars using high-yield weapons, if the small weapons are targeted at city centers. A single "small" nuclear detonation in an urban center could lead to more fatalities, in some cases by orders of magnitude, than have occurred in the major historical conflicts of many countries. We analyze the likely outcome of a regional nuclear exchange involving 100 15-kt explosions (less than 0.1% of the explosive yield of the current global nuclear arsenal). We find that such an exchange could produce direct fatalities comparable to all of those worldwide in World War II, or to those once estimated for a "counterforce" nuclear war between the superpowers. Megacities exposed to atmospheric fallout of long-lived radionuclides would likely be abandoned indefinitely, with severe national and international implications. Our analysis shows that smoke from urban firestorms in a regional war would rise into the upper troposphere due to pyro-convection. Robock et al. (2007) show that the smoke would subsequently rise deep into the stratosphere due

  10. Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism

    NASA Astrophysics Data System (ADS)

    Toon, O. B.; Turco, R. P.; Robock, A.; Bardeen, C.; Oman, L.; Stenchikov, G. L.

    2006-11-01

    We assess the potential damage and smoke production associated with the detonation of small nuclear weapons in modern megacities. While the number of nuclear warheads in the world has fallen by about a factor of three since its peak in 1986, the number of nuclear weapons states is increasing and the potential exists for numerous regional nuclear arms races. Eight countries are known to have nuclear weapons, 2 are constructing them, and an additional 32 nations already have the fissile material needed to build substantial arsenals of low-yield (Hiroshima-sized) explosives. Population and economic activity worldwide are congregated to an increasing extent in megacities, which might be targeted in a nuclear conflict. Our analysis shows that, per kiloton of yield, low yield weapons can produce 100 times as many fatalities and 100 times as much smoke from fires as high-yield weapons, if they are targeted at city centers. A single "small'' nuclear detonation in an urban center could lead to more fatalities, in some cases by orders of magnitude, than have occurred in the major historical conflicts of many countries. We analyze the likely outcome of a regional nuclear exchange involving 100 15-kt explosions (less than 0.1% of the explosive yield of the current global nuclear arsenal). We find that such an exchange could produce direct fatalities comparable to all of those worldwide in World War II, or to those once estimated for a "counterforce'' nuclear war between the superpowers. Megacities exposed to atmospheric fallout of long-lived radionuclides would likely be abandoned indefinitely, with severe national and international implications. Our analysis shows that smoke from urban firestorms in a regional war would rise into the upper troposphere due to pyro-convection. Robock et al. (2006) show that the smoke would subsequently rise deep into the stratosphere due to atmospheric heating, and then might induce significant climatic anomalies on global scales.We also

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  12. Bioactive and total endotoxins in atmospheric aerosols in the Pearl River Delta region, China

    NASA Astrophysics Data System (ADS)

    Cheng, Jessica Y. W.; Hui, Esther L. C.; Lau, Arthur P. S.

    2012-02-01

    Endotoxin, a toxic and pyrogenic substance in gram-negative bacteria in atmospheric aerosols was measured over a period of one year at Nansha, Guangzhou and Hong Kong in the Pearl River Delta region, China. Atmospheric aerosols were collected by high-volume samplers. The bioactive endotoxin levels in the samples were determined using the Limulus Amebocyte Lysate (LAL) assay after extraction with pyrogen-free water while the total endotoxin levels were measured by quantifying the biomarker, 3-hydroxy fatty acids (3-OHFAs) with GC-MS. Results showed that there was no significant difference (0.19 < p < 0.81) in the bioactive endotoxin level in PM 10 among sites (average concentrations ranged from 0.34 to 0.39 EU m -3). However, Hong Kong showed a significantly lower ( p < 0.05) total endotoxin level in PM 10 (average of 17.4 ng m -3) compared with Nansha's 29.4 ng m -3 and Guangzhou's 32.7 ng m -3. The bioactive endotoxins were found to be associated with the coarse mode (PM 2.5-10) of the particulates of natural origins while the total endotoxins were associated more with the fine mode (PM 2.5) of the particulates of anthropogenic origins. When normalized with particulate mass, the endotoxin loading is much higher in summer as a result of the increased growth of the bacteria when climatic conditions are favorable. The chemically determined total endotoxins were 3-4 orders of magnitude higher than the bioactive endotoxins quantified using the LAL assay. Correlation analyses between the bioactive endotoxins and 3-OHFAs with different carbon length were analyzed. Results showed that the correlations detected vary among sites and particulate sizes. Although no generalization between the total and bioactive endotoxins can be drawn from the study, the levels reported in this study suggests that the discrepancies between the two measurement approaches, and the bioactive potential of 3-OHFAs with individual carbon chains deserve further investigation.

  13. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating.

  14. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. PMID:27344510

  15. Biomass burning influences on atmospheric composition: A case study to assess the impact of aerosol data assimilation

    NASA Astrophysics Data System (ADS)

    Keslake, Tim; Chipperfield, Martyn; Mann, Graham; Flemming, Johannes; Remy, Sam; Dhomse, Sandip; Morgan, Will

    2016-04-01

    The C-IFS (Composition Integrated Forecast System) developed under the MACC series of projects and to be continued under the Copernicus Atmospheric Monitoring System, provides global operational forecasts and re-analyses of atmospheric composition at high spatial resolution (T255, ~80km). Currently there are 2 aerosol schemes implemented within C-IFS, a mass-based scheme with externally mixed particle types and an aerosol microphysics scheme (GLOMAP-mode). The simpler mass-based scheme is the current operational system, also used in the existing system to assimilate satellite measurements of aerosol optical depth (AOD) for improved forecast capability. The microphysical GLOMAP scheme has now been implemented and evaluated in the latest C-IFS cycle alongside the mass-based scheme. The upgrade to the microphysical scheme provides for higher fidelity aerosol-radiation and aerosol-cloud interactions, accounting for global variations in size distribution and mixing state, and additional aerosol properties such as cloud condensation nuclei concentrations. The new scheme will also provide increased aerosol information when used as lateral boundary conditions for regional air quality models. Here we present a series of experiments highlighting the influence and accuracy of the two different aerosol schemes and the impact of MODIS AOD assimilation. In particular, we focus on the influence of biomass burning emissions on aerosol properties in the Amazon, comparing to ground-based and aircraft observations from the 2012 SAMBBA campaign. Biomass burning can affect regional air quality, human health, regional weather and the local energy budget. Tropical biomass burning generates particles primarily composed of particulate organic matter (POM) and black carbon (BC), the local ratio of these two different constituents often determining the properties and subsequent impacts of the aerosol particles. Therefore, the model's ability to capture the concentrations of these two

  16. The Influence of Glacial Ice Sheets on Atlantic Meridional Overturning Circulation Through Atmospheric Circulation Change under Glacial Climate

    NASA Astrophysics Data System (ADS)

    Sherriff-Tadano, S.; Abe-Ouchi, A.; Yoshimori, M.; Oka, A.; Chan, W. L.

    2014-12-01

    It is well known that glacial ice sheets (Laurentide, Fennoscandian and Antarctic ice sheets) exert a large influence on the climate including the atmospheric circulation. Moreover, recent climate modeling studies suggest that glacial ice sheets have a large impact on the Atlantic meridional overturning circulation (AMOC). However, the process by which the ice sheets impact on the AMOC is not yet fully understood. On the other hand, recent studies showed that surface wind changes play a crucial role on changes to the AMOC under glacial climate. Therefore, in this study, we investigate in detail, the process by which the ice sheet modifies the AMOC through surface wind change. Here we conduct numerical experiments using an atmospheric general circulation model (AGCM) and an ocean general circulation model (OGCM) separately. Our method consists of 2 steps. First, from AGCM experiments, we evaluate the effect of glacial ice sheets on the surface wind. Second, from OGCM experiments, we evaluate the influence of the wind stress change on the AMOC by applying the surface wind change as a boundary condition, while leaving other boundary conditions (surface heat and water fluxes) unchanged. In addition, we conduct several sensitivity experiments. Using the AGCM, we explore individual ice sheet effect, ice sheet topography effect and albedo effect on surface wind change. Moreover, using the OGCM, we change the surface wind gradually or apply the surface wind change only at a specific region in order to explore the wind change effect in detail. We find that glacial ice sheets largely intensify the AMOC by surface wind change under glacial climate. Compare to other regions, it reveals that the wind change at the North Atlantic (NA) is a key region. There, the northern glacial ice sheet topography intensifies the Icelandic Low and anti-cyclonic circulation over the Laurentide ice sheet. However, this wind effect is effective only when the NA is not widely covered by sea ice

  17. Solar influences on spatial patterns of Eurasian winter temperature and atmospheric general circulation anomalies

    NASA Astrophysics Data System (ADS)

    Chen, Haishan; Ma, Hedi; Li, Xing; Sun, Shanlei

    2015-09-01

    Solar influences on spatial patterns of Eurasian winter climate and possible mechanisms are investigated based on a multiple linear regression method and multisource observational and reanalysis data. Robust and significant solar signals are detected in Eurasian surface air temperature (SAT), and strong solar activity evidently warms most area of the continent. The spatial pattern of sea level pressure (SLP) responses to solar activity is similar but not identical to that of the North Atlantic Oscillation (NAO). Compared to the NAO, geographic distribution of solar-induced SLP anomalies shifts eastward, with significantly enhanced influences over northern Eurasia. Relatively weaker solar signals were also found in mid-to-upper troposphere. The spatial pattern of 500 hPa geopotential anomalies resembles a negative Scandinavia teleconnection pattern, and the 200 hPa subtropical jet is weakened, while zonal wind at high latitudes is enhanced due to strong solar activity. The anomalous zonal circulations can be attributed to the "top-down" mechanism. During high solar activity winters, an enhanced stratospheric zonal wind anomaly propagates downward, causing zonal wind anomalies in the troposphere. However, the "bottom-up" mechanisms may provide more reasonable explanations of the distinct solar influences on Eurasian climate. Solar-induced strong warm advection in lower atmosphere tends to increase SAT but decrease SLP, resulting in enhanced solar influences over northern Eurasia. Meanwhile, change in the land-ocean thermal contrast (LOTC) could also amplify the circulation anomaly. Inhomogeneous surface heating caused by anomalous solar activity modifies LOTC, which probably enhances the solar-induced circulation patterns. Such a positive feedback may potentially strengthen the solar influences.

  18. Characterizing the Influence of Hemispheric Transport on Regional Air Pollution

    EPA Science Inventory

    Expansion of the coupled WRF-CMAQ modeling system to hemispheric scales is pursued to enable the development of a robust modeling framework in which the interactions between atmospheric processes occurring at various spatial and temporal scales can be examined in a consistent man...

  19. Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

    PubMed

    Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

    2014-01-01

    Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices.

  20. Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

    PubMed

    Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

    2014-01-01

    Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices. PMID:24308778

  1. Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?

    PubMed

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Moon, Hyo-Bang; Kwok, Karen Y; Lam, Paul K S; Horii, Yuichi; Petrick, Gert; Kannan, Kurunthachalam

    2013-05-01

    Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote

  2. Evidence of Energy Supply by Active-Region Spicules to the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Zeighami, S.; Ahangarzadeh Maralani, A. R.; Tavabi, E.; Ajabshirizadeh, A.

    2016-03-01

    We investigate the role of active-region spicules in the mass balance of the solar wind and energy supply in heating the solar atmosphere. We use high-cadence observations from the Solar Optical Telescope (SOT) onboard the Hinode satellite in the Ca ii H-line filter obtained on 26 January 2007. The observational technique provides the high spatio-temporal resolution required to detect fine structures such as spicules. We apply a Fourier power spectrum and wavelet analysis to Hinode/SOT time series of an active-region data set to explore the existence of coherent intensity oscillations. Coherent waves could be evidence of energy transport that serves to heat the solar atmosphere. Using time series, we measure the phase difference between two intensity profiles obtained at two different heights, which gives information about the phase difference between oscillations at those heights as a function of frequency. The results of a fast Fourier transform (FFT) show peaks in the power spectrum at frequencies in the range from 2 to 8 mHz at four different heights (above the limb), while the wavelet analysis indicates dominant frequencies similar to those of the Fourier power spectrum results. A coherency study indicates coherent oscillations at about 5.5 mHz (3 min). We measure mean phase speeds in the range 250-425 km s^{-1} increasing with height. The energy flux of these waves is estimated to be F = 1.8 × 106-11.2 × 106 erg cm^{-2} s^{-1} or 1.8-11.2 kW m^{-2}, which indicates that they are sufficiently energetic to accelerate the solar wind and heat the corona to temperatures of several million degrees. We compute the the mass flux carried by spicules of 3 × 10^{-10}-2 × 10^{-9} g cm^{-2} s^{-1}, which is 10-60 times higher than the mass that is carried away from the corona because of the solar wind (about 3 × 10^{-11} g cm^{-2} s^{-1}). Therefore, our results indicate that about 0.02-0.1 of the spicule mass is ejected from the corona, while the remainder reverts

  3. Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?

    PubMed

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Moon, Hyo-Bang; Kwok, Karen Y; Lam, Paul K S; Horii, Yuichi; Petrick, Gert; Kannan, Kurunthachalam

    2013-05-01

    Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote

  4. The importance of source configuration in quantifying footprints of regional atmospheric sulphur deposition.

    PubMed

    Vieno, M; Dore, A J; Bealey, W J; Stevenson, D S; Sutton, M A

    2010-01-15

    An atmospheric transport-chemistry model is applied to investigate the effects of source configuration in simulating regional sulphur deposition footprints from elevated point sources. Dry and wet depositions of sulphur are calculated for each of the 69 largest point sources in the UK. Deposition contributions for each point source are calculated for 2003, as well as for a 2010 emissions scenario. The 2010 emissions scenario has been chosen to simulate the Gothenburg protocol emission scenario. Point source location is found to be a major driver of the dry/wet deposition ratio for each deposition footprint, with increased precipitation scavenging of SO(x) in hill areas resulting in a larger fraction of the emitted sulphur being deposited within the UK for sources located near these areas. This reduces exported transboundary pollution, but, associated with the occurrence of sensitive soils in hill areas, increases the domestic threat of soil acidification. The simulation of plume rise using individual stack parameters for each point source demonstrates a high sensitivity of SO(2) surface concentration to effective source height. This emphasises the importance of using site-specific information for each major stack, which is rarely included in regional atmospheric pollution models, due to the difficulty in obtaining the required input data. The simulations quantify how the fraction of emitted SO(x) exported from the UK increases with source magnitude, effective source height and easterly location. The modelled reduction in SO(x) emissions, between 2003 and 2010 resulted in a smaller fraction being exported, with the result that the reductions in SO(x) deposition to the UK are less than proportionate to the emission reduction. This non-linearity is associated with a relatively larger fraction of the SO(2) being converted to sulphate aerosol for the 2010 scenario, in the presence of ammonia. The effect results in less-than-proportional UK benefits of reducing in SO(2

  5. Regional Climate Simulations with COSMO-CLM for West Africa using different soil-vegetation-atmosphere-transfer module's (SVAT's)

    NASA Astrophysics Data System (ADS)

    Breil, Marcus; Panitz, Hans-Jürgen

    2013-04-01

    Climate predictions on decadal timescales constitute a new field of research, closing the gap between short-term and seasonal weather predictions and long-term climate projections. Therefore, the Federal Ministry of Education and Research in Germany (BMBF) has recently funded the research program MiKlip (Mittelfristige Klimaprognosen), which aims to create a model system that can provide reliable decadal climate forecasts. Recent studies have suggested that one region with high potential decadal predictability is West Africa. Therefore, the DEPARTURE project (DEcadal Prediction of African Rainfall and ATlantic HURricanE Activity) was established within the MiKlip program to assess the feasibility and the potential added value of regional decadal climate predictions for West Africa. To quantify the potential decadal climate predictability, a multi-model approach with the three different regional climate models REMO, WRF and COSMO-CLM (CCLM) will be realized. The presented research will contribute to DEPARTURE by performing hindcast ensemble simulations with CCLM, based on SST-driven global MPI-ESM-LR simulations. Thereby, one focus is on the dynamic soil-vegetation-climate interaction on decadal timescales. Recent studies indicate that there are significant feedbacks between the land-surface and the atmosphere, which might influence the decadal climate variability substantially. To investigate this connection, three different SVAT's (TERRA_ML, Community Land Model (CLM), and VEG3D) will be coupled with the CCLM. Thus, sensitive model parameters shall be identified, whereby the understanding of important processes might be improved. As a first step, the influence of the model domain on the CCLM results was examined. For this purpose, recent CCLM results from simulations for the official CORDEX domain were compared with CCLM results achieved by using an extended DEPARTURE model domain to about 60°W. This sensitivity analysis was performed with a horizontal resolution

  6. The influence of glacial ice sheets on Atlantic meridional overturning circulation through atmospheric circulation change under glacial climate

    NASA Astrophysics Data System (ADS)

    Sherriff-Tadano, Sam; Abe-Ouchi, Ayako; Yoshimori, Masakazu; Oka, Akira; Chan, Wing-Le

    2016-04-01

    Recent coupled modeling studies have shown that the existence of the glacial ice sheets intensifies the Atlantic meridional overturning circulation (AMOC). Since this may play an important role in maintaining a strong AMOC over the last glacial period, which is suggested by recent reconstruction study, it is very important to understand the process by which glacial ice sheets intensify the AMOC. Here, a decoupled simulation is conducted to investigate the effect of wind change due to glacial ice sheets on the AMOC, the crucial region where wind modifies the AMOC and the mechanism, which remained elusive in previous studies. First, from atmospheric general circulation model (AGCM) experiments, the effect of glacial ice sheets on the surface wind is evaluated. Second, from ocean general circulation model (OGCM) experiments, the influence of the wind stress change on the AMOC is evaluated by applying only the changes in the surface wind as a boundary condition, while leaving surface heat and freshwater fluxes unchanged. Moreover, several sensitivity experiments are conducted. Using the AGCM, glacial ice sheets are applied individually. Using the OGCM, changes in the wind are applied regionally or at different magnitudes, ranging from the full glacial to modern levels. These experiments demonstrate that glacial ice sheets intensify the AMOC through an increase in the wind stress curl mainly at the North Atlantic mid-latitudes. This intensification is caused by the increased Ekman upwelling and gyre transport of salt while the change in sea ice transport works as a negative, though minor, feedback.

  7. Estimating the Influence of Biological Ice Nuclei on Clouds with Regional Scale Simulations

    NASA Astrophysics Data System (ADS)

    Hummel, Matthias; Hoose, Corinna; Schaupp, Caroline; Möhler, Ottmar

    2014-05-01

    Cloud properties are largely influenced by the atmospheric formation of ice particles. Some primary biological aerosol particles (PBAP), e.g. certain bacteria, fungal spores or pollen, have been identified as effective ice nuclei (IN). The work presented here quantifies the IN concentrations originating from PBAP in order to estimate their influences on clouds with the regional scale atmospheric model COSMO-ART in a six day case study for Western Europe. The atmospheric particle distribution is calculated for three different PBAP (bacteria, fungal spores and birch pollen). The parameterizations for heterogeneous ice nucleation of PBAP are derived from AIDA cloud chamber experiments with Pseudomonas syringae bacteria and birch pollen (Schaupp, 2013) and from published data on Cladosporium spores (Iannone et al., 2011). A constant fraction of ice-active bacteria and fungal spores relative to the total bacteria and spore concentration had to be assumed. At cloud altitude, average simulated PBAP number concentrations are ~17 L-1 for bacteria and fungal spores and ~0.03 L-1 for birch pollen, including large temporal and spatial variations of more than one order of magnitude. Thus, the average, 'diagnostic' in-cloud PBAP IN concentrations, which only depend on the PBAP concentrations and temperature, without applying dynamics and cloud microphysics, lie at the lower end of the range of typically observed atmospheric IN concentrations . Average PBAP IN concentrations are between 10-6 L-1 and 10-4 L-1. Locally but not very frequently, PBAP IN concentrations can be as high as 0.2 L-1 at -10° C. Two simulations are compared to estimate the cloud impact of PBAP IN, both including mineral dust as an additional background IN with a constant concentration of 100 L-1. One of the simulations includes additional PBAP IN which can alter the cloud properties compared to the reference simulation without PBAP IN. The difference in ice particle and cloud droplet concentration between

  8. Recent surface mass balance from Syowa Station to Dome F, East Antarctica: comparison of field observations, atmospheric reanalyses, and a regional atmospheric climate model

    NASA Astrophysics Data System (ADS)

    Wang, Yetang; Hou, Shugui; Sun, Weijun; Lenaerts, Jan T. M.; van den Broeke, Michiel R.; van Wessem, J. M.

    2015-11-01

    Stake measurements at 2 km intervals are used to determine the spatial and temporal surface mass balance (SMB) in recent decades along the Japanese Antarctic Research Expedition traverse route from Syowa Station to Dome F. To determine SMB variability at regional scales, this traverse route is divided into four regions, i.e., coastal, lower katabatic, upper katabatic and inland plateau. We also perform a regional evaluation of large scale SMB simulated by the regional atmospheric climate model versions 2.1 and 2.3 (RACMO2.1 and RACMO2.3), and the four more recent global reanalyses. Large-scale spatial variability in the multi-year averaged SMB reveals robust relationships with continentality and surface elevation. In the katabatic regions, SMB variability is also highly associated with surface slope, which in turn is affected by bedrock topography. Stake observation records show large inter-annual variability in SMB, but did not indicate any significant trends over both the last 40 years for the coastal and lower katabatic regions, and the last 20 years record for the upper katabatic and inland plateau regions. The four reanalyses and the regional climate model reproduce the macro-scale spatial pattern well for the multi-year averaged SMB, but fail to capture the mesoscale SMB increase at the distance interval ~300 to ~400 km from Syowa station. Thanks to the updated scheme in the cloud microphysics, RACMO2.3 shows the best spatial agreement with stake measurements over the inland plateau region. ERA-interim, JRA-55 and MERRA exhibit high agreement with the inter-annual variability of observed SMB in the coastal, upper katabatic and inland plateau regions, and moderate agreement in the lower katabatic region, while NCEP2 and RACMO2.1 inter-annual variability shows no significant correlation with the observations for the inland plateau region.

  9. Do Weather-Related Ambient Atmospheric-Pressure Changes Influence Sleep Disordered Breathing?

    PubMed Central

    Doherty, Michael John; Youn, Clover E.; Haltiner, Alan Matthew; Watson, Nathaniel Fletcher

    2010-01-01

    Objective: High-altitude studies of sleep disordered breathing (SDB) show increases in apnea hypopnea indices with elevation gains. Hypoxic changes, rather than reductions in atmospheric pressure (AP), are thought to be the driving factor. Ambient pressure-related changes in SDB have not been extensively studied at low altitude. We performed a cross-sectional study of weather-related AP effects on measures of SDB at the University of Washington Medicine Sleep Institute, a Seattle, Washington-based polysomnography lab located 200 feet above sea level. Method: Obstructive, central, and apnea-hypopnea indices from 537 patients were retrospectively correlated to mean 8-hour date-matched overnight AP data. Linear regression analysis and interquartile comparison of AP-related respiratory indices were performed and adjusted for age, sex, and body mass index. Results: The obstructive apnea index increased with lower weather-related APs (p = 0.01 for linear trend), interquartile analysis showed significant worsening with lowered mean, minimum, and maximum nightly APs. Similar changes were not seen with central or apnea-hypopnea indices. Conclusions: The obstructive apnea index is altered by changes in weather-related AP during diagnostic polysomnography performed at 200 feet above sea level. Small changes in ambient atmospheric pressure due to weather systems may be important in the pathophysiology and diagnosis of obstructive sleep apnea. Citation: Doherty MJ; Youn CE; Haltiner AM; Watson NF. Do weather-related ambient atmospheric-pressure changes influence sleep disordered breathing? J Clin Sleep Med 2010;6(2):152-156. PMID:20411692

  10. Modelling soil-plant-atmosphere interactions by coupling the regional weather model WRF to mechanistic plant models

    NASA Astrophysics Data System (ADS)

    Klein, C.; Hoffmann, P.; Priesack, E.

    2012-04-01

    Climate change causes altering distributions of meteorological factors influencing plant growth and its interactions between the land surface and the atmosphere. Recent studies show, that uncertainties in regional and global climate simulations are also caused by lacking descriptions of the soil-plant-atmosphere system. Therefore, we couple a mechanistic soil-plant model to a regional climate and forecast model. The detailed simulation of the water and energy exchanges, especially the transpiration of grassland and forests stands, are the key features of the modelling framework. The Weather Research and Forecasting model (WRF) (Skamarock 2008) is an open source mesoscale numerical weather prediction model. The WRF model was modified in a way, to either choose its native, static land surface model NOAH or the mechanistic eco-system model Expert-N 5.0 individually for every single grid point within the simulation domain. The Expert-N 5.0 modelling framework provides a highly modular structure, enabling the development and use of a large variety of different plant and soil models, including heat transfer, nitrogen uptake/turnover/transport as well as water uptake/transport and crop management. To represent the key landuse types grassland and forest, we selected two mechanistic plant models: The Hurley Pasture model (Thornley 1998) and a modified TREEDYN3 forest simulation model (Bossel 1996). The models simulate plant growth, water, nitrogen and carbon flows for grassland and forest stands. A mosaic approach enables Expert-N to use high resolution land use data e.g. CORINE Land Cover data (CLC, 2006) for the simulation, making it possible to simulate different land use distributions within a single grid cell. The coupling results are analyzed for plausibility and compared with the results of the default land surface model NOAH (Fei Chen and Jimy Dudhia 2010). We show differences between the mechanistic and the static model coupling, with focus on the feedback effects

  11. Marine aerosol source regions to Prince of Wales Icefield, Ellesmere Island, and influence from the tropical Pacific, 1979-2001

    NASA Astrophysics Data System (ADS)

    Criscitiello, Alison S.; Marshall, Shawn J.; Evans, Matthew J.; Kinnard, Christophe; Norman, Ann-Lise; Sharp, Martin J.

    2016-08-01

    Using a coastal ice core collected from Prince of Wales (POW) Icefield on Ellesmere Island, we investigate source regions of sea ice-modulated chemical species (methanesulfonic acid (MSA) and chloride (Cl-)) to POW Icefield and the influence of large-scale atmospheric variability on the transport of these marine aerosols (1979-2001). Our key findings are (1) MSA in the POW Icefield core is derived primarily from productivity in the sea ice zone of Baffin Bay and the Labrador Sea, with influence from waters within the North Water (NOW) polynya, (2) sea ice formation processes within the NOW polynya may be a significant source of sea-salt aerosols to the POW core site, in addition to offshore open water source regions primarily in Hudson Bay, and (3) the tropical Pacific influences the source and transport of marine aerosols to POW Icefield through its remote control on regional winds and sea ice variability. Regression analyses during times of MSA deposition reveal sea level pressure (SLP) anomalies favorable for opening of the NOW polynya and subsequent oceanic dimethyl sulfide production. Regression analyses during times of Cl- deposition reveal SLP anomalies that indicate a broader oceanic region of sea-salt sources to the core site. These results are supported by Scanning Multichannel Microwave Radiometer- and Special Sensor Microwave/Imager-based sea ice reconstructions and air mass transport density analyses and suggest that the marine biogenic record may capture local polynya variability, while sea-salt transport to the site from larger offshore source regions in Baffin Bay is likely. Regression analyses show a link to tropical dynamics via an atmospheric Rossby wave.

  12. Influence of large-scale atmospheric circulation on marine air intrusion toward the East Antarctic coast

    NASA Astrophysics Data System (ADS)

    Kurita, Naoyuki; Hirasawa, Naohiko; Koga, Seizi; Matsushita, Junji; Steen-Larsen, Hans Christian; Masson-Delmotte, Valérie; Fujiyoshi, Yasushi

    2016-09-01

    Marine air intrusions into Antarctica play a key role in high-precipitation events. Here we use shipboard observations of water vapor isotopologues between Australia and Syowa on the East Antarctic coast to elucidate the mechanism by which large-scale circulation influences marine air intrusions. The temporal isotopic variations at Syowa reflect the meridional movement of a marine air front. They are also associated with atmospheric circulation anomalies that enhance the southward movement of cyclones over the Southern Ocean. The relationship between large-scale circulation and the movement of the front is explained by northerly winds which, in association with cyclones, move toward the Antarctic coast and push marine air with isotopically enriched moisture into the inland covered by glacial air with depleted isotopic values. Future changes in large-scale circulation may have a significant impact on the frequency and intensity of marine air intrusion into Antarctica.

  13. Improving adhesion of powder coating on PEEK composite: Influence of atmospheric plasma parameters

    NASA Astrophysics Data System (ADS)

    Dupuis, Aurélie; Ho, Thu Huong; Fahs, Ahmad; Lafabrier, Aurore; Louarn, Guy; Bacharouche, Jalal; Airoudj, Aissam; Aragon, Emmanuel; Chailan, Jean-François

    2015-12-01

    In aeronautic industries, powder coatings are increasingly used because of environmental considerations. During the deposition of such a coating on a substrate piece, the main objective is to obtain a good coating/substrate adhesion. In this study, the targeted substrate is a Poly-(Ether EtherKetone)-(PEEK) based composite material. Due to the poor surface energy of PEEK, a surface treatment is necessary in order to enhance its adhesion with the coating. In this purpose, atmospheric plasma treatment has been chosen and the influence of plasma parameters has been studied. Four scan speed nozzles and three gases (Air, N2 and Argon) plasma has been tested. The increase of adhesion with increasing wettability, polarity and nanoroughness has been evidenced. A particular study of the type of grafted polar functionalities according to gas nature allowed to better understand the plasma mechanism and the cross-impact of polarity and nanoroughness in adhesion enhancement.

  14. Influence of scattering, atmospheric refraction, and ground effect on sound propagation through a pine forest.

    PubMed

    Swearingen, Michelle E; White, Michael J

    2007-07-01

    Sound propagation through a forest is affected by the microclimate in the canopy, scattering by trunks and stems, and ground reflection. Each of these effects is such a strong contributor to the attenuation of sound that mutual interactions between the phenomena could become important. A sound propagation model for use in a forest has been developed that incorporates scattering from trunks and branches and atmospheric refraction by modifying the effective wave number in the Green's function parabolic equation model. The ground effect for a hard-backed pine straw layer is approximated as a local reaction impedance condition. Comparisons to experimental data are made for frequencies up to 4,200 Hz. Cumulative influences of the separate phenomena are examined. The method developed in this paper is compared to previously published methods. The overall comparison with spectral transmission data is good, suggesting that the model captures the necessary details. PMID:17614470

  15. Atmospheric pressure plasma pretreatment of sugarcane bagasse: the influence of moisture in the ozonation process.

    PubMed

    Souza-Corrêa, J A; Oliveira, C; Wolf, L D; Nascimento, V M; Rocha, G J M; Amorim, J

    2013-09-01

    Sugarcane bagasse samples were pretreated with ozone via atmospheric O2 pressure plasma. A delignification efficiency of approximately 80 % was observed within 6 h of treatment. Some hemicelluloses were removed, and the cellulose was not affected by ozonolysis. The quantity of moisture in the bagasse had a large influence on delignification and saccharification after ozonation pretreatment of the bagasse, where 50 % moisture content was found to be best for delignification (65 % of the cellulose was converted into glucose). Optical absorption spectroscopy was applied to determine ozone concentrations in real time. The ozone consumption as a function of the delignification process revealed two main reaction phases, as the ozone molecules cleave the strong carbon-carbon bonds of aromatic rings more slowly than the weak carbon-carbon bonds of aliphatic chains.

  16. Osseointegration of atmospheric plasma-sprayed titanium implants: Influence of the native oxide layer.

    PubMed

    Cunha, Alexandre; Renz, Renata Pedrolli; Blando, Eduardo; de Oliveira, Rogério Belle; Hübler, Roberto

    2014-01-01

    The aim of this study was to evaluate in vivo the influence of the native oxide layer on osseointegration and new bone formation on the surface of atmospheric plasma-sprayed porous titanium coatings. Porous titanium coatings were deposited on all implant surfaces, and half of the samples were subsequently submitted to oxide layer removal treatment. Samples were implanted onto the cortical bone of sheep (tibia) and evaluated at 30 and 60 days. Implants were removed en bloc and the attachment of bone to implants was examined by tensile pull-out test (osseointegration assessment), light microscopy, scanning electron microscopy (histological analysis), and instrumented hardness tests (mechanical properties of mature and newly formed bone tissue). Coatings submitted to oxide layer treatment presented higher osseointegration values at both healing periods and showed more mature and mineralized bone tissue when compared with nontreated coatings. Our findings showed that the use of acid-etching in association with atmospheric plasma spraying techniques improves osseointegration of titanium implants.

  17. Influence of modified atmosphere packaging on meat quality parameters of turkey breast muscles.

    PubMed

    Blacha, Ines; Krischek, Carsten; Klein, Günter

    2014-01-01

    Poultry meat is often stored in modified atmosphere packaging (MAP) or vacuum packaging to improve consumer acceptance and shelf life. The aim of this study was to determine how different packaging conditions influence meat quality. Therefore, in three independent experiments, turkey breast muscle cutlets were packaged either in vacuum or in different modified atmosphere mixtures (80% O2, 20% CO2 [MAP 1]; 80% N2, 20% CO2 [MAP 2]; and 20% O2, 20% CO2, 60% N2 [MAP 3]) and stored for 12 days at 3°C. Color, pH, electrical conductivity, total viable counts, and Pseudomonas species were determined on days 1, 4, 8, and 12 of storage. On the same days, samples were collected for analysis of thiobarbituric acid-reactive substance and total volatile basic nitrogen concentrations. Sensory parameters and liquid loss were determined on days 4, 8, and 12. Vacuum-packaged meat had the highest liquid loss and lowest sensory results. MAP 1-packaged meat showed the highest sensory, redness, and thiobarbituric acid-reactive substance values. MAP 2-packaged meat had lower sensory values. MAP 3-packaged meat had lower redness and sensory values, especially at the end of storage. The study showed an impact of the packaging condition on different quality parameters, with a small advantage for storage of turkey cutlets in high-oxygen packages.

  18. [Influence of atmospheric transport on air pollutant levels at a mountain background site of East China].

    PubMed

    Su, Bin-Bin; Xu, Ju-Yang; Zhang, Ruo-Yu; Ji, Xian-Xin

    2014-08-01

    Transport characteristics of air pollutants transported to the background atmosphere of East China were investigated using HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) 4.8 model driven by NCEP reanalysis data during June 2011 to May 2012. Based on the air pollutants monitoring data collected at the National atmospheric background monitoring station (Wuyishan station) in Fujian Province, characteristics of different clustered air masses as well as the origins of highly polluted air masses were further examined. The results showed that 65% of all the trajectories, in which air masses mainly passed over highly polluted area of East China, Jiangxi province and upper air in desert areas of Northwest China, carried polluted air to the station, while the rest of trajectories (35%) with air masses originated from ocean could effectively remove air pollutants at the Wuyishan station. However, the impact on the air pollutants for each air mass group varied with seasons. Elevated SO2 concentrations observed at the background station were mainly influenced by coal burning activities in Northern China during heating season. The high CO concentrations were likely associated with the pollutants emission in the process of coal production and consumption in Anhui province. The elevated NO(x), O3, PM10 and PM2.5 concentrations were mostly impacted by East China with high levels of air pollutants.

  19. Halocarbons in the atmosphere of the industrial-related Pearl River Delta region of China

    NASA Astrophysics Data System (ADS)

    Chan, L. Y.; Chu, K. W.

    2007-02-01

    In a study conducted in 2000, 19 halocarbons from 78 canister air samples were measured in five industrial cities in the Pearl River Delta (PRD), one of the fastest growing industrial regions in China. Preliminary year 2000 halocarbon levels have been derived using available data and information. Comparisons have been made between the data obtained in this study and the corresponding estimated global/tropical surface mixing ratios obtained from the literature. With the exception of CFC-114 and halon-2402, the halocarbons had significant enhancements, presumably due to their recent increased production and extensive industrial uses. In contrast to the small enhancements (<7%) for two chlorofluorocarbons (CFC-11 and CFC-12), large enhancements (>30%) for three HCFC replacements (HCFC-22, -141b, -142b) were observed. In general, HCFCs have virtually replaced CFCs, except for some localized usage. The median of HFC-134a also had a 36% enhancement; however, 23% of the samples were near or at the global background level. These contradictory results could not give a clear situation of uses of this new chemical in the region. Our data also indicate that halocarbon-based cleaning solvents, including CFC-113, methyl chloroform, trichloroethene and tetrachloroethene, were still frequently used in PRD industries. High mixing ratios of these halogenated solvents were frequently measured in Dongguan, a city with light industry. Higher atmospheric levels of the three methyl halides (-Cl, -Br, and -I) were found in a coastal city, Jiangmen. These may be contributed to by industrial emissions and coastal terrestrial and coastal seawater sources.

  20. Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions

    NASA Astrophysics Data System (ADS)

    Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; Andersen, Stephen O.; McFarland, Mack

    2015-12-01

    Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0-5.3 GtCO2-eq yr-1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40-58%) and stationary air conditioning (21-40%) are the major use sectors. The corresponding radiative forcing could reach 0.22-0.25 W m-2 in 2050, which would be 12-24% of the increase from business-as-usual CO2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries.

  1. Aerosol variability and atmospheric transport in the Himalayan region from CALIOP 2007-2010 observations

    NASA Astrophysics Data System (ADS)

    Bucci, S.; Cagnazzo, C.; Cairo, F.; Di Liberto, L.; Fierli, F.

    2014-05-01

    This work quantifies the spatial distribution of different aerosol types, their seasonal variability and sources.The analysis of four years of CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) vertically resolved aerosol data allows the identification of spatial patterns of desert dust and carbonaceous particles in different atmospheric layers. Clusters of Lagrangian back trajectories highlight the transport pathways from source regions during the dusty spring season. The analysis shows a prevalence of dust; at low heights it occurs frequently (up to 70% of available observations) and is distributed north of the Tibetan Plateau with a main contribution from the Gobi and Taklamakan deserts, and west of the Tibetan Plateau, originating from the deserts of southwest Asia and advected by the Westerlies. Above the Himalayas the dust amount is minor but still not negligible (occurrence around 20%) and mainly affected by the transport from more distant deserts sources (Sahara and Arabian Peninsula). Carbonaceous aerosol, produced mainly in northern India and eastern China, is subject to shorter-range transport and is indeed observed closer to the sources, while there is a limited amount reaching the top of the plateau. Data analysis reveals a clear seasonal variability in the frequencies of occurrence for the main aerosol types; dust is regulated principally by the monsoon dynamics, with maximal occurrence in spring. We also highlight relevant interannual differences, showing a larger presence of aerosol in the region during 2007 and 2008. The characterization of the aerosol spatial and temporal distribution in terms of observational frequency is a key piece of information that can be directly used for the evaluation of global aerosol models.

  2. CMAQ (Community Multi-Scale Air Quality) atmospheric distribution model adaptation to region of Hungary

    NASA Astrophysics Data System (ADS)

    Lázár, Dóra; Weidinger, Tamás

    2016-04-01

    For our days, it has become important to measure and predict the concentration of harmful atmospheric pollutants such as dust, aerosol particles of different size ranges, nitrogen compounds, and ozone. The Department of Meteorology at Eötvös Loránd University has been applying the WRF (Weather Research and Forecasting) model several years ago, which is suitable for weather forecasting tasks and provides input data for various environmental models (e.g. DNDC). By adapting the CMAQ (Community Multi-scale Air Quality) model we have designed a combined ambient air-meteorological model (WRF-CMAQ). In this research it is important to apply different emission databases and a background model describing the initial distribution of the pollutant. We used SMOKE (Sparse Matrix Operator Kernel Emissions) model for construction emission dataset from EMEP (European Monitoring and Evaluation Programme) inventories and GEOS-Chem model for initial and boundary conditions. Our model settings were CMAQ CB05 (Carbon Bond 2005) chemical mechanism with 108 x 108 km, 36 x 36 km and 12 x 12 km grids for regions of Europe, the Carpathian Basin and Hungary respectively. i) The structure of the model system, ii) a case study for Carpathian Basin (an anticyclonic weather situation at 21th September 2012) are presented. iii) Verification of ozone forecast has been provided based on the measurements of background air pollution stations. iv) Effects of model attributes (f.e. transition time, emission dataset, parameterizations) for the ozone forecast in Hungary are also investigated.

  3. On testing two major cumulus parameterization schemes using the CSU Regional Atmospheric Modeling System

    SciTech Connect

    Kao, C.Y.J.; Bossert, J.E.; Winterkamp, J.; Lai, C.C.

    1993-10-01

    One of the objectives of the DOE ARM Program is to improve the parameterization of clouds in general circulation models (GCMs). The approach taken in this research is two fold. We first examine the behavior of cumulus parameterization schemes by comparing their performance against the results from explicit cloud simulations with state-of-the-art microphysics. This is conducted in a two-dimensional (2-D) configuration of an idealized convective system. We then apply the cumulus parameterization schemes to realistic three-dimensional (3-D) simulations over the western US for a case with an enormous amount of convection in an extended period of five days. In the 2-D idealized tests, cloud effects are parameterized in the ``parameterization cases`` with a coarse resolution, whereas each cloud is explicitly resolved by the ``microphysics cases`` with a much finer resolution. Thus, the capability of the parameterization schemes in reproducing the growth and life cycle of a convective system can then be evaluated. These 2-D tests will form the basis for further 3-D realistic simulations which have the model resolution equivalent to that of the next generation of GCMs. Two cumulus parameterizations are used in this research: the Arakawa-Schubert (A-S) scheme (Arakawa and Schubert, 1974) used in Kao and Ogura (1987) and the Kuo scheme (Kuo, 1974) used in Tremback (1990). The numerical model used in this research is the Regional Atmospheric Modeling System (RAMS) developed at Colorado State University (CSU).

  4. Local and regional factors affecting atmospheric mercury speciation at a remote location

    USGS Publications Warehouse

    Manolopoulos, H.; Schauer, J.J.; Purcell, M.D.; Rudolph, T.M.; Olson, M.L.; Rodger, B.; Krabbenhoft, D.P.

    2007-01-01

    Atmospheric concentrations of elemental (Hg0), reactive gaseous (RGM), and particulate (PHg) mercury were measured at two remote sites in the midwestern United States. Concurrent measurements of Hg0, PHg, and RGM obtained at Devil's Lake and Mt. Horeb, located approximately 65 km apart, showed that Hg0 and PHg concentrations were affected by regional, as well as local sources, while RGM was mainly impacted by local sources. Plumes reaching the Devil's Lake site from a nearby coal-fired power plant significantly impacted SO2 and RGM concentrations at Devil's Lake, but had little impact on Hg0. Our findings suggest that traditional modeling approaches to assess sources of mercury deposited that utilize source emissions and large-scale grids may not be sufficient to predict mercury deposition at sensitive locations due to the importance of small-scale sources and processes. We suggest the use of a receptor-based monitoring to better understand mercury source-receptor relationships. ?? 2007 NRC Canada.

  5. Preliminary evaluation of a regional atmospheric chemical data assimilation system for environmental surveillance.

    PubMed

    Lee, Pius; Liu, Yang

    2014-12-01

    We report the progress of an ongoing effort by the Air Resources Laboratory,NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data.We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm.We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention.

  6. Preliminary evaluation of a regional atmospheric chemical data assimilation system for environmental surveillance.

    PubMed

    Lee, Pius; Liu, Yang

    2014-12-11

    We report the progress of an ongoing effort by the Air Resources Laboratory, NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data. We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm. We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention.

  7. Preliminary Evaluation of a Regional Atmospheric Chemical Data Assimilation System for Environmental Surveillance

    PubMed Central

    Lee, Pius; Liu, Yang

    2014-01-01

    We report the progress of an ongoing effort by the Air Resources Laboratory, NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data. We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm. We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention. PMID:25514141

  8. The Rossby Centre Regional Atmospheric Climate Model part II: application to the Arctic climate.

    PubMed

    Jones, Colin G; Wyser, Klaus; Ullerstig, Anders; Willén, Ulrika

    2004-06-01

    The Rossby Centre regional climate model (RCA2) has been integrated over the Arctic Ocean as part of the international ARCMIP project. Results have been compared to observations derived from the SHEBA data set. The standard RCA2 model overpredicts cloud cover and downwelling longwave radiation, during the Arctic winter. This error was improved by introducing a new cloud parameterization, which significantly improves the annual cycle of cloud cover. Compensating biases between clear sky downwelling longwave radiation and longwave radiation emitted from cloud base were identified. Modifications have been introduced to the model radiation scheme that more accurately treat solar radiation interaction with ice crystals. This leads to a more realistic representation of cloud-solar radiation interaction. The clear sky portion of the model radiation code transmits too much solar radiation through the atmosphere, producing a positive bias at the top of the frequent boundary layer clouds. A realistic treatment of the temporally evolving albedo, of both sea-ice and snow, appears crucial for an accurate simulation of the net surface energy budget. Likewise, inclusion of a prognostic snow-surface temperature seems necessary, to accurately simulate near-surface thermodynamic processes in the Arctic.

  9. Regional Sea Level Changes Projected by the NASA/GISS Atmosphere-Ocean Model

    NASA Technical Reports Server (NTRS)

    Russell, Gary L.; Gornitz, Vivien; Miller, James R.

    1999-01-01

    Sea level has been rising for the past century, and inhabitants of the Earth's coastal regions will want to understand and predict future sea level changes. In this study we present results from new simulations of the Goddard Institute for Space Studies (GISS) global atmosphere-ocean model from 1950 to 2099. Model results are compared with observed sea level changes during the past 40 years at 17 coastal stations around the world. Using observed levels of greenhouse gases between 1950 and 1990 and a compounded 0.5% annual increase in Co2 after 1990, model projections show that global sea level measured from 1950 will rise by 61 mm in the year 2000, by 212 mm in 2050, and by 408 mm in 2089. By 2089, two thirds of the global sea level rise will be due to thermal expansion and one third will be due to ocean mass changes. The spatial distribution of sea level rise is different than that projected by rigid lid ocean models.

  10. Evaluation of the Regional Atmospheric Modeling System in the Eastern Range Dispersion Assessment System

    NASA Technical Reports Server (NTRS)

    Case, Jonathan

    2000-01-01

    The Applied Meteorology Unit is conducting an evaluation of the Regional Atmospheric Modeling System (RAMS) contained within the Eastern Range Dispersion Assessment System (ERDAS). ERDAS provides emergency response guidance for operations at the Cape Canaveral Air Force Station and the Kennedy Space Center in the event of an accidental hazardous material release or aborted vehicle launch. The prognostic data from RAMS is available to ERDAS for display and is used to initialize the 45th Range Safety (45 SW/SE) dispersion model. Thus, the accuracy of the 45 SW/SE dispersion model is dependent upon the accuracy of RAMS forecasts. The RAMS evaluation task consists of an objective and subjective component for the Florida warm and cool seasons of 1999-2000. The objective evaluation includes gridded and point error statistics at surface and upper-level observational sites, a comparison of the model errors to a coarser grid configuration of RAMS, and a benchmark of RAMS against the widely accepted Eta model. The warm-season subjective evaluation involves a verification of the onset and movement of the Florida east coast sea breeze and RAMS forecast precipitation. This interim report provides a summary of the RAMS objective and subjective evaluation for the 1999 Florida warm season only.

  11. Preliminary evaluation of a regional atmospheric chemical data assimilation system for environmental surveillance.

    PubMed

    Lee, Pius; Liu, Yang

    2014-12-01

    We report the progress of an ongoing effort by the Air Resources Laboratory,NOAA to build a prototype regional Chemical Analysis System (ARLCAS). The ARLCAS focuses on providing long-term analysis of the three dimensional (3D) air-pollutant concentration fields over the continental U.S. It leverages expertise from the NASA Earth Science Division-sponsored Air Quality Applied Science Team (AQAST) for the state-of-science knowledge in atmospheric and data assimilation sciences. The ARLCAS complies with national operational center requirement protocols and aims to have the modeling system to be maintained by a national center. Meteorology and chemistry observations consist of land-, air- and space-based observed and quality-assured data.We develop modularized testing to investigate the efficacies of the various components of the ARLCAS. The sensitivity testing of data assimilation schemes showed that with the increment of additional observational data sets, the accuracy of the analysis chemical fields also increased incrementally in varying margins. The benefit is especially noted for additional data sets based on a different platform and/or a different retrieval algorithm.We also described a plan to apply the analysis chemical fields in environmental surveillance at the Centers for Disease Control and Prevention. PMID:25587606

  12. The Evaluation of the Regional Atmospheric Modeling System in the Eastern Range Dispersion Assessment System

    NASA Technical Reports Server (NTRS)

    Case, Jonathan

    2001-01-01

    The Applied Meteorology Unit (AMU) evaluated the Regional Atmospheric Modeling System (RAMS) contained within the Eastern Range Dispersion Assessment System (ERDAS). ERDAS provides emergency response guidance for Cape Canaveral Air Force Station and Kennedy Space Center operations in the event of an accidental hazardous material release or aborted vehicle launch. The RAMS prognostic data are available to ERDAS for display and are used to initialize the 45th Space Wing/Range Safety dispersion model. Thus, the accuracy of the dispersion predictions is dependent upon the accuracy of RAMS forecasts. The RAMS evaluation consisted of an objective and subjective component for the 1999 and 2000 Florida warm seasons, and the 1999-2000 cool season. In the objective evaluation, the AMU generated model error statistics at surface and upper-level observational sites, compared RAMS errors to a coarser RAMS grid configuration, and benchmarked RAMS against the nationally-used Eta model. In the subjective evaluation, the AMU compared forecast cold fronts, low-level temperature inversions, and precipitation to observations during the 1999-2000 cool season, verified the development of the RAMS forecast east coast sea breeze during both warm seasons, and examined the RAMS daily thunderstorm initiation and precipitation patterns during the 2000 warm season. This report summarizes the objective and subjective verification for all three seasons.

  13. Improving estimations of greenhouse gas transfer velocities by atmosphere-ocean couplers in Earth-System and regional models

    NASA Astrophysics Data System (ADS)

    Vieira, V. M. N. C. S.; Sahlée, E.; Jurus, P.; Clementi, E.; Pettersson, H.; Mateus, M.

    2015-09-01

    Earth-System and regional models, forecasting climate change and its impacts, simulate atmosphere-ocean gas exchanges using classical yet too simple generalizations relying on wind speed as the sole mediator while neglecting factors as sea-surface agitation, atmospheric stability, current drag with the bottom, rain and surfactants. These were proved fundamental for accurate estimates, particularly in the coastal ocean, where a significant part of the atmosphere-ocean greenhouse gas exchanges occurs. We include several of these factors in a customizable algorithm proposed for the basis of novel couplers of the atmospheric and oceanographic model components. We tested performances with measured and simulated data from the European coastal ocean, having found our algorithm to forecast greenhouse gas exchanges largely different from the forecasted by the generalization currently in use. Our algorithm allows calculus vectorization and parallel processing, improving computational speed roughly 12× in a single cpu core, an essential feature for Earth-System models applications.

  14. Precipitation extremes over Amazonia - atmospheric and oceanic associated features observed and simulated by HADGEM2-ES, CPTEC/INPE AGCM and Eta/CPTEC regional model

    NASA Astrophysics Data System (ADS)

    Cavalcanti, I. F.

    2013-05-01

    Extreme monthly cases of precipitation (positive and negative anomalies) over Amazonia are analyzed to show the atmospheric and oceanic related features and the ability of CPTEC AGCM and HADGEM2-ES in simulating them. Humidity flux variability over the Tropical Atlantic region is analyzed related to the precipitation variability over Amazonia. Besides the Pacific Ocean influence, the Amazonia precipitation is affected by the Tropical Atlantic Ocean, both by the SST and atmospheric flux humidity. Correlations between Atlantic SST and Amazonia precipitation show that there are specific months and areas that are affected by SST anomalies. The extreme cases are obtained from the Standardized Precipitation Index (SPI) applied to monthly data in four areas of Amazonia: northwest, northeast, west and east areas. The period of analysis is 1981 to 2010 to GPCP observed precipitation and CPTEC/INPE AGCM. As this AGCM is the base of the Brazilian Model of Earth System, its behavior on the mechanisms leading to extremes over Amazonia, compared to observations is discussed. Projections of extremes over the region are analyzed with results from CMIP5 HADGEM2-ES during 2073-2099 compared to 1979-2005. The regional Eta CPTEC model is also analyzed in two periods: 1960 to 1990 and 2040 to 2070, with boundary conditions of CMIP3 HADCM3 A1B scenario. The relevance of this analysis is to identify changes in frequency and intensity of extremes in the Amazon region in a higher resolution than the global models.

  15. Role of atmospheric heating over the South China Sea and western Pacific regions in modulating Asian summer climate under the global warming background

    NASA Astrophysics Data System (ADS)

    He, Bian; Yang, Song; Li, Zhenning

    2016-05-01

    The response of monsoon precipitation to global warming, which is one of the most significant climate change signals at the earth's surface, exhibits very distinct regional features, especially over the South China Sea (SCS) and adjacent regions in boreal summer. To understand the possible atmospheric dynamics in these specific regions under the global warming background, changes in atmospheric heating and their possible influences on Asian summer climate are investigated by both observational diagnosis and numerical simulations. Results indicate that heating in the middle troposphere has intensified in the SCS and western Pacific regions in boreal summer, accompanied by increased precipitation, cloud cover, and lower-tropospheric convergence and decreased sea level pressure. Sensitivity experiments show that middle and upper tropospheric heating causes an east-west feedback pattern between SCS and western Pacific and continental South Asia, which strengthens the South Asian High in the upper troposphere and moist convergence in the lower troposphere, consequently forcing a descending motion and adiabatic warming over continental South Asia. When air-sea interaction is considered, the simulation results are overall more similar to observations, and in particular the bias of precipitation over the Indian Ocean simulated by AGCMs has been reduced. The result highlights the important role of air-sea interaction in understanding the changes in Asian climate.

  16. Increasing Mississippi river discharge throughout the twenty-first century influenced by changes in climate, land use and atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Tao, B.; Tian, H.; Ren, W.; Yang, J.; Yang, Q.; He, R.; Cai, W. J.; Lohrenz, S. E.

    2014-12-01

    Previous studies have demonstrated that changes in temperature and precipitation (hereafter climate change) would influence river discharge, but the relative importance of climate change, land use, and elevated atmospheric CO2 have not yet been fully investigated. Here we examined how river discharge in the Mississippi River basin in the 21st century might be influenced by these factors using the Dynamic Land Ecosystem Model driven by atmospheric CO2, downscaled GCMs climate and land use scenarios. Our results suggest that river discharge would be substantially enhanced (10.7-59.8%) by the 2090s compared to the recent decade (2000s), though large discrepancies exist among different climate, atmospheric CO2, and land use change scenarios. Our factorial analyses further indicate that the combined effects of land use change and human-induced atmospheric CO2 elevation on river discharge would outweigh climate change effect under the high emission scenario (A2) of Intergovernmental Panel for Climate Change. Our study offers the first attempt to project potential changes in river discharge in response to multiple future environmental changes. It demonstrates the importance of land use change and atmospheric CO2 concentrations in projecting future changes in hydrologic processes. The projected increase river discharge implies that riverine fluxes of carbon, nutrients and pesticide from the MRB to the coastal regions would increase in the future, and thus may influence the states of ocean acidification and hypoxia and deteriorate ocean water quality. Further efforts will also be needed to account for additional environmental factors (such as nitrogen deposition, tropospheric ozone pollution, dam construction, etc.) in projecting changes in the hydrological cycle.

  17. Influence of daily versus monthly fire emissions on atmospheric model applications in the tropics

    NASA Astrophysics Data System (ADS)

    Marlier, M. E.; Voulgarakis, A.; Faluvegi, G.; Shindell, D. T.; DeFries, R. S.

    2012-12-01

    Fires are widely used throughout the tropics to create and maintain areas for agriculture, but are also significant contributors to atmospheric trace gas and aerosol concentrations. However, the timing and magnitude of fire activity can vary strongly by year and ecosystem type. For example, frequent, low intensity fires dominate in African savannas whereas Southeast Asian peatland forests are susceptible to huge pulses of emissions during regional El Niño droughts. Despite the potential implications for modeling interactions with atmospheric chemistry and transport, fire emissions have commonly been input into global models at a monthly resolution. Recognizing the uncertainty that this can introduce, several datasets have parsed fire emissions to daily and sub-daily scales with satellite active fire detections. In this study, we explore differences between utilizing the monthly and daily Global Fire Emissions Database version 3 (GFED3) products as inputs into the NASA GISS-E2 composition climate model. We aim to understand how the choice of the temporal resolution of fire emissions affects uncertainty with respect to several common applications of global models: atmospheric chemistry, air quality, and climate. Focusing our analysis on tropical ozone, carbon monoxide, and aerosols, we compare modeled concentrations with available ground and satellite observations. We find that increasing the temporal frequency of fire emissions from monthly to daily can improve correlations with observations, predominately in areas or during seasons more heavily affected by fires. Differences between the two datasets are more evident with public health applications: daily resolution fire emissions increases the number of days exceeding World Health Organization air quality targets.

  18. Local and regional effects of large scale atmospheric circulation patterns on winter wind power output in Western Europe

    NASA Astrophysics Data System (ADS)

    Zubiate, Laura; McDermott, Frank; Sweeney, Conor; O'Malley, Mark

    2014-05-01

    Recent studies (Brayshaw, 2009, Garcia-Bustamante, 2010, Garcia-Bustamante, 2013) have drawn attention to the sensitivity of wind speed distributions and likely wind energy power output in Western Europe to changes in low-frequency, large scale atmospheric circulation patterns such as the North Atlantic Oscillation (NAO). Wind speed variations and directional shifts as a function of the NAO state can be larger or smaller depending on the North Atlantic region that is considered. Wind speeds in Ireland and the UK for example are approximately 20 % higher during NAO + phases, and up to 30 % lower during NAO - phases relative to the long-term (30 year) climatological means. By contrast, in southern Europe, wind speeds are 15 % lower than average during NAO + phases and 15 % higher than average during NAO - phases. Crucially however, some regions such as Brittany in N.W. France have been identified in which there is negligible variability in wind speeds as a function of the NAO phase, as observed in the ERA-Interim 0.5 degree gridded reanalysis database. However, the magnitude of these effects on wind conditions is temporally and spatially non-stationary. As described by Comas-Bru and McDermott (2013) for temperature and precipitation, such non-stationarity is caused by the influence of two other patterns, the East Atlantic pattern, (EA), and the Scandinavian pattern, (SCA), which modulate the position of the NAO dipole. This phenomenon has also implications for wind speeds and directions, which has been assessed using the ERA-Interim reanalysis dataset and the indices obtained from the PC analysis of sea level pressure over the Atlantic region. In order to study the implications for power production, the interaction of the NAO and the other teleconnection patterns with local topography was also analysed, as well as how these interactions ultimately translate into wind power output. The objective is to have a better defined relationship between wind speed and power

  19. Pollution influences on atmospheric composition and chemistry at high northern latitudes: Boreal and California forest fire emissions

    NASA Astrophysics Data System (ADS)

    Singh, H. B.; Anderson, B. E.; Brune, W. H.; Cai, C.; Cohen, R. C.; Crawford, J. H.; Cubison, M. J.; Czech, E. P.; Emmons, L.; Fuelberg, H. E.; Huey, G.; Jacob, D. J.; Jimenez, J. L.; Kaduwela, A.; Kondo, Y.; Mao, J.; Olson, J. R.; Sachse, G. W.; Vay, S. A.; Weinheimer, A.; Wennberg, P. O.; Wisthaler, A.; The Arctas Science Team

    2010-11-01

    We analyze detailed atmospheric gas/aerosol composition data acquired during the 2008 NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) airborne campaign performed at high northern latitudes in spring (ARCTAS-A) and summer (ARCTAS-B) and in California in summer (ARCTAS-CARB). Biomass burning influences were widespread throughout the ARCTAS campaign. MODIS data from 2000 to 2009 indicated that 2008 had the second largest fire counts over Siberia and a more normal Canadian boreal forest fire season. Near surface arctic air in spring contained strong anthropogenic signatures indicated by high sulfate. In both spring and summer most of the pollution plumes transported to the Arctic region were from Europe and Asia and were present in the mid to upper troposphere and contained a mix of forest fire and urban influences. The gas/aerosol composition of the high latitude troposphere was strongly perturbed at all altitudes in both spring and summer. The reactive nitrogen budget was balanced with PAN as the dominant component. Mean ozone concentrations in the high latitude troposphere were only minimally perturbed (<5 ppb), although many individual pollution plumes sampled in the mid to upper troposphere, and mixed with urban influences, contained elevated ozone (ΔO 3/ΔCO = 0.11 ± 0.09 v/v). Emission and optical characteristics of boreal and California wild fires were quantified and found to be broadly comparable. Greenhouse gas emission estimates derived from ARCTAS-CARB data for the South Coast Air Basin of California show good agreement with state inventories for CO 2 and N 2O but indicate substantially larger emissions of CH 4. Simulations by multiple models of transport and chemistry were found to be broadly consistent with observations with a tendency towards under prediction at high latitudes.

  20. Influence of the radiation pressure on the planetary exospheres: density profiles, escape flux and atmospheric stability

    NASA Astrophysics Data System (ADS)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Mazelle, C.

    2015-10-01

    The uppermost layer of the atmosphere, the exosphere,is not well-known in its global structure since the densities are very low compared to instrument detection capabilities. Because of rare collisions and high Knudsen numbers, the motion of light species (H,H2, ...)in the corona is essentially determined by the external forces : the gravitation from the planet, the radiation pressure, as well the stellar gravity. In this work, we calculate rigorously and analytically,based on the Hamiltonian mechanics and Liouville theorem, the impact of the radiation pressure and gravitation from the planet on the structure of the exosphere. This approach was partially used by Bishop and Chamberlain (1989) but only in the 2D case : we extend it to the 3D case. Assuming a collisionless exosphere and a constant radiation pressure near the planet, we determine the density profiles for ballistic particles (the main contribution for densities in the lower exosphere) for light species as a function of the angle with respect to the Sun direction. We also obtain an analytical formula for the escape flux at the subsolar point, which can be compared with the Jeans' escape flux. Finally, we study the effect of the radiation pressure on the zero velocity curves, position of the Roche lobe and Hill's region for the well-known Three-Body problem especially for Hot Jupiters and discuss about the validity of our model. The goal is to bring some constraints on modelling of exoplanet atmospheres.

  1. Tracking the MSL-SAM methane detection source location Through Mars Regional Atmospheric Modeling System (MRAMS)

    NASA Astrophysics Data System (ADS)

    Pla-García, Jorge

    2016-04-01

    olivine indicate could be the case, then it might explain the observed fast destruction of methane [7]. In an effort to better address the potential mixing and remaining questions, atmospheric circulation studies of Gale Crater were performed with the Mars Re-gional Atmospheric Modeling System (MRAMS). The model was focused on rover locations using nested grids with a spacing of 330 meters on the in-nermost grid that is centered over the landing [8, 9]. MRAMS is ideally suited for this investigation; the model is explicitly designed to simulate Mars' at-mospheric circulations at the mesoscale and smaller with realistic, high-resolution surface properties [10, 11]. In order to characterize seasonal mixing changes throughout the Martian year, simulations were con-ducted at Ls 0, 90, 180 and 270. Two additional sim-ulations at Ls 225 and 315 were explored to better understand the unique meteorological setting cen-tered around Ls 270. Ls 270 was shown to be an anomalous season when air within and outside the crater was well mixed by strong, flushing, northerly flow and large amplitude breaking mountain waves: air flowing downslope at night is cold enough to penetrate all the way to the surface. At other seasons, the air in the crater is more isolated -but not com-pletely- from the surrounding environment: mesoscale simulations indicate that the air flowing down the crater rims does not easily make it to the crater floor. Instead, the air encounters very cold and stable air pooled in the bottom of the crater, which forces the air to glide right over the colder, more dense air below. Thus, the mixing of near-surface crater air with the external environment is potentially more limited than around Ls 270. 2. Tracking methane source location The rise in concentration was reported to start around sol 300 (˜Ls 336), peaked shortly after sol 520 (˜Ls 82), and then dropped to background val-ues prior to sol 575 (˜Ls 103). Two scenarios are considered in the context of the

  2. Optical parametric oscillators in lidar sounding of trace atmospheric gases in the mid infrared region

    NASA Astrophysics Data System (ADS)

    Romanovskii, O. A.; Sadovnikov, S. A.; Kharchenko, O. V.; Shumskii, V. K.; Yakovlev, S. V.

    2015-12-01

    Applicability of a KTA crystal-based laser system with optical parametric generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases is based on differential absorption (DIAL) technique and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases.

  3. Atmospheric three-dimensional inverse modeling of regional industrial emissions and global oceanic uptake of carbon tetrachloride

    NASA Astrophysics Data System (ADS)

    Xiao, X.; Prinn, R. G.; Fraser, P. J.; Weiss, R. F.; Simmonds, P. G.; O'Doherty, S.; Miller, B. R.; Salameh, P. K.; Harth, C. M.; Krummel, P. B.; Golombek, A.; Porter, L. W.; Butler, J. H.; Elkins, J. W.; Dutton, G. S.; Hall, B. D.; Steele, L. P.; Wang, R. H. J.; Cunnold, D. M.

    2010-11-01

    Carbon tetrachloride (CCl4) has substantial stratospheric ozone depletion potential and its consumption is controlled under the Montreal Protocol and its amendments. We implement a Kalman filter using atmospheric CCl4 measurements and a 3-dimensional chemical transport model to estimate the interannual regional industrial emissions and seasonal global oceanic uptake of CCl4 for the period of 1996-2004. The Model of Atmospheric Transport and Chemistry (MATCH), driven by offline National Center for Environmental Prediction (NCEP) reanalysis meteorological fields, is used to simulate CCl4 mole fractions and calculate their sensitivities to regional sources and sinks using a finite difference approach. High frequency observations from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Earth System Research Laboratory (ESRL) of the National Oceanic and Atmospheric Administration (NOAA) and low frequency flask observations are together used to constrain the source and sink magnitudes, estimated as factors that multiply the a priori fluxes. Although industry data imply that the global industrial emissions were substantially declining with large interannual variations, the optimized results show only small interannual variations and a small decreasing trend. The global surface CCl4 mole fractions were declining in this period because the CCl4 oceanic and stratospheric sinks exceeded the industrial emissions. Compared to the a priori values, the inversion results indicate substantial increases in industrial emissions originating from the South Asian/Indian and Southeast Asian regions, and significant decreases in emissions from the European and North American regions.

  4. Regional Precipitation Forecast with Atmospheric InfraRed Sounder (AIRS) Profile Assimilation

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    Advanced technology in hyperspectral sensors such as the Atmospheric InfraRed Sounder (AIRS; Aumann et al. 2003) on NASA's polar orbiting Aqua satellite retrieve higher vertical resolution thermodynamic profiles than their predecessors due to increased spectral resolution. Although these capabilities do not replace the robust vertical resolution provided by radiosondes, they can serve as a complement to radiosondes in both space and time. These retrieved soundings can have a significant impact on weather forecasts if properly assimilated into prediction models. Several recent studies have evaluated the performance of specific operational weather forecast models when AIRS data are included in the assimilation process. LeMarshall et al. (2006) concluded that AIRS radiances significantly improved 500 hPa anomaly correlations in medium-range forecasts of the Global Forecast System (GFS) model. McCarty et al. (2009) demonstrated similar forecast improvement in 0-48 hour forecasts in an offline version of the operational North American Mesoscale (NAM) model when AIRS radiances were assimilated at the regional scale. Reale et al. (2008) showed improvements to Northern Hemisphere 500 hPa height anomaly correlations in NASA's Goddard Earth Observing System Model, Version 5 (GEOS-5) global system with the inclusion of partly cloudy AIRS temperature profiles. Singh et al. (2008) assimilated AIRS temperature and moisture profiles into a regional modeling system for a study of a heavy rainfall event during the summer monsoon season in Mumbai, India. This paper describes an approach to assimilate AIRS temperature and moisture profiles into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimensional variational (3DVAR) assimilation system (WRF-Var; Barker et al. 2004). Section 2 describes the AIRS instrument and how the quality indicators are used to intelligently select the highest-quality data for assimilation

  5. A Regional Atmospheric Continuous CO2 Network In The Rocky Mountains (Rocky RACCOON)

    NASA Astrophysics Data System (ADS)

    Stephens, B.; de Wekker, S.; Watt, A.; Schimel, D.

    2005-12-01

    We have established a continuous CO2 observing network in the Rocky Mountains, building on technological and modeling advances made during the Carbon in the Mountains Experiment (CME), to improve our understanding of regional carbon fluxes and to fill key gaps in the North American Carbon Program (NACP). We will present a description of the Rocky RACCOON network and early results from the first three sites. There are strong scientific and societal motivations for determining CO2 exchanges on regional scales. NACP aims to address these concerns through a dramatic expansion in observations and modeling capabilities over North America. Mountain forests in particular represent a significant potential net CO2 sink in the U.S. and are highly sensitive to land-use practices and climate change. However, plans for new continuous CO2 observing sites have omitted the mountain west. This resulted from expensive instrumentation in the face of limited resources, and a perception that current atmospheric transport models are not sophisticated enough to interpret CO2 measurements made in complex terrain. Through our efforts in CME, we have a new autonomous, inexpensive, and robust CO2 analysis system and are developing mountain CO2 modeling tools that will help us to overcome these obstacles. Preliminary observational and modeling results give us confidence that continuous CO2 observations from mountain top observatories will provide useful constraints on regional carbon cycling and will be valuable in the continental inverse modeling efforts planned for NACP. We began at three Colorado sites in August 2005 and hope to add three to six sites in other western states in subsequent years, utilizing existing observatories to the maximum extent possible. The first three sites are at Niwot Ridge, allowing us to have an ongoing intercomparison with flask measurements made by NOAA CMDL; at Storm Peak Laboratory near Steamboat Springs, allowing us to investigate comparisons between these

  6. Influence of preonset land atmospheric conditions on the Indian summer monsoon rainfall variability

    NASA Astrophysics Data System (ADS)

    Rai, Archana; Saha, Subodh K.; Pokhrel, Samir; Sujith, K.; Halder, Subhadeep

    2015-05-01

    A possible link between preonset land atmospheric conditions and the Indian summer monsoon rainfall (ISMR) is explored. It is shown that, the preonset positive (negative) rainfall anomaly over northwest India, Pakistan, Afghanistan, and Iran is associated with decrease (increase) in ISMR, primarily in the months of June and July, which in turn affects the seasonal mean. ISMR in the months of June and July is also strongly linked with the preonset 2 m air temperature over the same regions. The preonset rainfall/2 m air temperature variability is linked with stationary Rossby wave response, which is clearly evident in the wave activity flux diagnostics. As the predictability of Indian summer monsoon relies mainly on the El Niño-Southern Oscillation (ENSO), the found link may further enhance our ability to predict the monsoon, particularly during a non-ENSO year.

  7. Trans-Pacific and regional atmospheric transport of polycyclic aromatic hydrocarbons and pesticides in biomass burning emissions to western North America.

    PubMed

    Genualdi, Susan A; Killin, Robert K; Woods, Jim; Wilson, Glenn; Schmedding, David; Simonich, Staci L Massey

    2009-02-15

    The trans-Pacific and regional North American atmospheric transport of polycyclic aromatic hydrocarbons (PAHs) and pesticides in biomass burning emissions was measured in air masses from April to September 2003 at two remote sites in western North America. Mary's Peak Observatory (MPO) is located in Oregon's Coast Range and Cheeka Peak Observatory (CPO) is located on the tip of the Olympic Peninsula in Washington State. During this time period, both remote sites were influenced by PAH and pesticide emissions from forest fires in Siberia and regional fires in Oregon and Washington State. Concurrent samples were taken at both sites on June 2 and August 4, 2003. On these dates, CPO had elevated gas phase PAH, alpha-hexachlorocyclohexane, and retene concentrations (p < 0.05) and MPO had elevated retene, particulate phase PAH, and levoglucosan concentrations due to trans-Pacific transport of emissions from fires in Siberia. In addition, during the April to September 2003 sampling period, CPO and MPO were influenced by emissions from regional fires that resulted in elevated levoglucosan, dacthal, endosulfan, and gas phase PAH concentrations. Burned and unburned forest soil samples collected from the regional forest fire area showed that 34-100% of the pesticide mass was lost from soil due to burning. These data suggest that the trans-Pacific and regional atmospheric transport of biomass burning emissions results in elevated PAH and pesticide concentrations in western North America. The elevated pesticide concentrations are likely due to re-emission of historically deposited pesticides from the soil and vegetation during the fire event. PMID:19320158

  8. Anthropogenic Aerosol Radiative Forcing in Asia Derived From Regional Models With Atmospheric and Aerosol Data Assimilation

    SciTech Connect

    Chung, Chul Eddy; Ramanathan, V.; Carmichael, Gregory; Kulkarni, S.; Tang, Youhua; Adhikary, Bhupesh; Leung, Lai-Yung R.; Qian, Yun

    2010-07-05

    A high-resolution estimate of monthly 3D aerosol solar heating rates and surface solar fluxes in Asia from 2001 to 2004 is described here. This product stems from an Asian aerosol assimilation project, in which a) the PNNL regional model bounded by the NCEP reanalyses was used to provide meteorology, b) MODIS and AERONET data were integrated for aerosol observations, c) the Iowa aerosol/chemistry model STEM-2K1 used the PNNL meteorology and assimilated aerosol observations, and d) 3D (X-Y-Z) aerosol simulations from the STEM-2K1 were used in the Scripps Monte-Carlo Aerosol Cloud Radiation (MACR) model to produce total and anthropogenic aerosol direct solar forcing for average cloudy skies. The MACR model and STEM both used the PNNL model resolution of 0.45º×0.4º in the horizontal and of 23 layers in the troposphere. The 2001–2004 averaged anthropogenic all-sky aerosol forcing is -1.3 Wm-2 (TOA), +7.3 Wm-2 (atmosphere) and -8.6 Wm-2 (surface) averaged in Asia (60-138°E & Eq. -45°N). In the absence of AERONET SSA assimilation, absorbing aerosol concentration (especially BC aerosol) is much smaller, giving -2.3 Wm-2 (TOA), +4.5 Wm-2 (atmosphere) and -6.8 Wm-2 (surface), averaged in Asia. In the vertical, monthly forcing is mainly concentrated below 600hPa with maxima around 800hPa. Seasonally, low-level forcing is far larger in dry season than in wet season in South Asia, whereas the wet season forcing exceeds the dry season forcing in East Asia. The anthropogenic forcing in the present study is similar to that in Chung et al.’s [2005] in overall magnitude but the former offers fine-scale features and simulated vertical profiles. The interannual variability of the computed anthropogenic forcing is significant and extremely large over major emission outflow areas. In view of this, the present study’s estimate is within the implicated range of the 1999 INDOEX result. However, NCAR/CCSM3

  9. Atmospheric dry deposition of sulfur and nitrogen in the Athabasca Oil Sands Region, Alberta, Canada.

    PubMed

    Hsu, Yu-Mei; Bytnerowicz, Andrzej; Fenn, Mark E; Percy, Kevin E

    2016-10-15

    Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide (NO2), nitric acid/nitrous acid (HNO3/HONO), and sulfur dioxide (SO2) in the AOSR. Concentrations of NO2 and SO2 in winter were higher than those in summer, while seasonal differences of NH3 and HNO3/HONO showed an opposite trend, with higher values in summer. Concentrations of NH3, NO2 and SO2 were high close to the emission sources (oil sands operations and urban areas). NH3 concentrations were also elevated in the southern portion of the domain indicating possible agricultural and urban emission sources to the southwest. HNO3, an oxidation endpoint, showed wider ranges of concentrations and a larger spatial extent. Concentrations of NH3, NO2, HNO3/HONO and SO2 from passive measurements and their monthly deposition velocities calculated by a multi-layer inference model (MLM) were used to calculate dry deposition of N and S. NH3 contributed the largest fraction of deposited N across the network, ranging between 0.70-1.25kgNha(-1)yr(-1), HNO3/HONO deposition ranged between 0.30-0.90kgNha(-1)yr(-1), and NO2 deposition between 0.03-0.70kgNha(-1)yr(-1). During the modeled period, average dry deposition of the inorganic gaseous N species ranged between 1.03 and 2.85kgNha(-1)yr(-1) and SO4-S deposition ranged between 0.26 and 2.04kgha(-1)yr(-1). Comparisons with co-measured ion exchange resin throughfall data (8.51kgSha(-1)yr(-1)) indicate that modeled dry deposition combined with measured wet deposition (1.37kgSha(-1)yr(-1)) underestimated S deposition. Gas phase NH3 (71%) and HNO3 plus NO2 (79%) dry deposition fluxes dominated the total deposition of NH4-N and NO3-N, respectively.

  10. Atmospheric dry deposition of sulfur and nitrogen in the Athabasca Oil Sands Region, Alberta, Canada.

    PubMed

    Hsu, Yu-Mei; Bytnerowicz, Andrzej; Fenn, Mark E; Percy, Kevin E

    2016-10-15

    Due to the potential ecological effects on terrestrial and aquatic ecosystems from atmospheric deposition in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, this study was implemented to estimate atmospheric nitrogen (N) and sulfur (S) inputs. Passive samplers were used to measure ambient concentrations of ammonia (NH3), nitrogen dioxide (NO2), nitric acid/nitrous acid (HNO3/HONO), and sulfur dioxide (SO2) in the AOSR. Concentrations of NO2 and SO2 in winter were higher than those in summer, while seasonal differences of NH3 and HNO3/HONO showed an opposite trend, with higher values in summer. Concentrations of NH3, NO2 and SO2 were high close to the emission sources (oil sands operations and urban areas). NH3 concentrations were also elevated in the southern portion of the domain indicating possible agricultural and urban emission sources to the southwest. HNO3, an oxidation endpoint, showed wider ranges of concentrations and a larger spatial extent. Concentrations of NH3, NO2, HNO3/HONO and SO2 from passive measurements and their monthly deposition velocities calculated by a multi-layer inference model (MLM) were used to calculate dry deposition of N and S. NH3 contributed the largest fraction of deposited N across the network, ranging between 0.70-1.25kgNha(-1)yr(-1), HNO3/HONO deposition ranged between 0.30-0.90kgNha(-1)yr(-1), and NO2 deposition between 0.03-0.70kgNha(-1)yr(-1). During the modeled period, average dry deposition of the inorganic gaseous N species ranged between 1.03 and 2.85kgNha(-1)yr(-1) and SO4-S deposition ranged between 0.26 and 2.04kgha(-1)yr(-1). Comparisons with co-measured ion exchange resin throughfall data (8.51kgSha(-1)yr(-1)) indicate that modeled dry deposition combined with measured wet deposition (1.37kgSha(-1)yr(-1)) underestimated S deposition. Gas phase NH3 (71%) and HNO3 plus NO2 (79%) dry deposition fluxes dominated the total deposition of NH4-N and NO3-N, respectively. PMID:27295600

  11. Interglacial Surface Ocean Temperatures Reveal Strong Ocean-Atmosphere Linkages Between the Subtropical and Subpolar Regions

    NASA Astrophysics Data System (ADS)

    Kandiano, E.; Bauch, H. A.; Fahl, K.; Helmke, J.; Roehl, U.

    2008-12-01

    Investigating ocean-atmospheric processes of past interglaciations may provide a better understanding of the climatic development of the present warm period. Here we present a detailed reconstruction of the meridional sea surface temperature (SST) across MIS 11 using three sites: ODP 958 (off NW Africa), ODP 975 (western Mediterranean Sea) and M23414 (subpolar NE Atlantic). Sea surface temperatures (SST) were derived from foraminiferal assemblages and alkenones, further supported by planktic and benthic O-isotope records as well as by iron content, the latter as indicator for Saharan dust export and continental dryness. On a large scale, reconstructed SSTs reveal a close synchronism of environmental changes between all three sites. It shows that, before full interglacial conditions became established, there was a long-lasting, glacial- interglacial transition with a total temperature increase of about 10°C in the subtropical as well as in the subpolar North Atlantic. After the main glacial-interglacial transition was over, SSTs continued to rise and reached their maximum during, what could be considered, the upper main phase of high sea-level stand in MIS 11. In the western Mediterranean SSTs show several cooling events with amplitudes of up to 4°C during the early full-interglacial warm period. Off NW Africa this phase is characterized by rather humid conditions, as inferred from strongly decreased values of iron in the sediments, and successive changes in the foraminiferal assemblages. We assume that these rather wet conditions at the lower latitudes were related to an intensification of the West African monsoon that increased summer moisture flux over Northwest Africa and runoff into the Mediterranean. At the same time increased abundance of subtropical, deep- dwelling foraminiferal species are found in the subpolar region implying a strong linkage between the subtropical atmospheric circulation regime over NW Africa and the northward propagation, of

  12. Visual Empirical Region of Influence (VERI) Pattern Recognition Algorithms

    2002-05-01

    We developed new pattern recognition (PR) algorithms based on a human visual perception model. We named these algorithms Visual Empirical Region of Influence (VERI) algorithms. To compare the new algorithm's effectiveness against othe PR algorithms, we benchmarked their clustering capabilities with a standard set of two-dimensional data that is well known in the PR community. The VERI algorithm succeeded in clustering all the data correctly. No existing algorithm had previously clustered all the pattens inmore » the data set successfully. The commands to execute VERI algorithms are quite difficult to master when executed from a DOS command line. The algorithm requires several parameters to operate correctly. From our own experiences we realized that if we wanted to provide a new data analysis tool to the PR community we would have to provide a new data analysis tool to the PR community we would have to make the tool powerful, yet easy and intuitive to use. That was our motivation for developing graphical user interfaces (GUI's) to the VERI algorithms. We developed GUI's to control the VERI algorithm in a single pass mode and in an optimization mode. We also developed a visualization technique that allows users to graphically animate and visually inspect multi-dimensional data after it has been classified by the VERI algorithms. The visualization technique that allows users to graphically animate and visually inspect multi-dimensional data after it has been classified by the VERI algorithms. The visualization package is integrated into the single pass interface. Both the single pass interface and optimization interface are part of the PR software package we have developed and make available to other users. The single pass mode only finds PR results for the sets of features in the data set that are manually requested by the user. The optimization model uses a brute force method of searching through the cominations of features in a data set for features that produce

  13. Atmospheric composition in the Eastern Mediterranean: Influence of biomass burning during summertime using the WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Bossioli, E.; Tombrou, M.; Kalogiros, J.; Allan, J.; Bacak, A.; Bezantakos, S.; Biskos, G.; Coe, H.; Jones, B. T.; Kouvarakis, G.; Mihalopoulos, N.; Percival, C. J.

    2016-05-01

    The composition of the atmosphere over the Aegean Sea (AS) during an 'Etesian' outbreak under the influence of biomass burning (BB) activity is investigated. Simulations with the fully coupled WRF-Chem model during the Aegean-GAME campaign (29/8-9/9/2011) are used to examine the BB effect over the region. Two distinct Etesian flow patterns characterized by different transport conditions are analysed. The influence of the off-line calculated BB emissions on the atmospheric chemical composition over the AS under these conditions is estimated. In addition, sensitivity runs are used to examine the influence of the biogenic emissions calculated on-line and the realistic representation of the stratosphere-troposphere exchange processes are investigated through the time-varying chemical boundary conditions from the MOZART global chemical transport model. The horizontal and vertical distributions of gaseous and aerosol species are simulated under long-range transport conditions and interpreted in relation to the evolution of the Planetary Boundary Layer (PBL). In the case of a weaker synoptic system (medium-range transport conditions), even a small variability of meteorological parameters in limited areas become critical for the spatial distribution of gases and aerosols. The BB activity increases O3, PM2.5 and organic matter concentrations up to 5.5 ppb, 5.8 μg m-3 and 3.3 μg m-3, respectively. The spatial extent of the simulated BB plumes is further examined by comparison with airborne measurements of hydrogen cyanide (HCN). The estimated effect of biogenic emissions on O3 and PM2.5 concentrations is either positive or negative (±6 ppb for O3 and up to ± 1 μg m-3 for PM2.5) depending on the emission algorithm employed. The realistic representation of the chemical boundary conditions reproduces an observed layer rich in O3 above 4 km, but also increases O3 concentrations inside the PBL by up to 40%.

  14. The influence of atmospheric blocking on extreme winter minimum temperatures in North America

    NASA Astrophysics Data System (ADS)

    Whan, Kirien; Zwiers, Francis; Sillmann, Jana

    2016-04-01

    Regional climate models (RCMs) are the primary source of high-resolution climate projections and it is of crucial importance to evaluate their ability to simulate extreme events under current climate conditions. Many extreme events are influenced by circulation features that occur outside, or on the edges of, RCM domains. Thus it is of interest to know whether such dynamically controlled aspects of extremes are well represented by RCMs. This study assesses the relationship between upstream blocking and cold temperature extremes over North America in observations, reanalysis products (ERA-Interim, NARR) and RCMs (CanRCM4, CRCM5, HIRHAM5, RCA4). Generalized extreme value distributions were fitted to winter minimum temperature (TNn) incorporating blocking frequency (BF) as a covariate, which has a significant influence on TNn. The magnitude of blocking influence in the RCMs is consistent with observations but the spatial extent varies. CRCM5 and HIRHAM5 reproduce the pattern of influence best compared to observations. CanRCM4 and RCA4 capture the influence of blocking in British Columbia and the northeastern United States but the extension of influence that is seen in observations and reanalysis, into the southern United States is not evident. The difference in the 20-year return value (20RV) of TNn between high and low BF indicates that blocking is associated with a decrease of up to 15°C in the 20RV over the majority of the United States and in western Canada. In northern North America the difference in the 20RV is positive as blocking is associated with warmer temperatures. The 20RVs are generally simulated well by the RCMs.

  15. Influence of annealing atmospheres and synthetic air treatment on solution processed zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Busch, C.; Schierning, G.; Theissmann, R.; Schmechel, R.

    2012-08-01

    Thin film transistors (TFTs) based on active layers of zinc oxide prepared from a solution process were fabricated under different annealing conditions. The influence of the annealing gas as well as the influence of a subsequent exposure to synthetic air to the device properties is considered. Annealing under N2 or H2 atmosphere leads to a strong negative threshold voltage shift. With respect to known defect states in ZnO, two different donor states are suggested to be responsible for the negative threshold voltage. A subsequent synthetic air treatment causes in general a positive threshold voltage shift. However, transistors annealed under H2 degrade very fast under synthetic air in contrast to transistors annealed under N2. In order to obtain more information about the density of states (DOS) distribution, a transistor model for thin film transistors in the hopping transport regime (Vissenberg model) was utilized. For positive threshold voltages, the DOS distribution is independent from the gas treatment and the threshold voltage within the experimental accuracy. This indicates a shift of the Fermi-level within an exponentially decaying DOS. The change in the charge carrier density is either due to shallow donors or due to a charge transfer with acceptors at the surface. In contrast, for negative threshold voltages, the DOS distribution parameter rises, indicating a flatter DOS distribution. We suggest that the difference is due to the change from accumulation mode to the depletion mode of the device.

  16. Composition of LHB Comets and Their Influence on the Early Earth Atmosphere Composition

    NASA Technical Reports Server (NTRS)

    Tornow, C.; Kupper, S.; Ilgner, M.; Kuehrt, E.; Motschmann, U.

    2011-01-01

    Two main processes were responsible for the composition of this atmosphere: chemical evolution of the volatile fraction of the accretion material forming the planet and the delivery of gasses to the planetary surface by impactors during the late heavy bombardment (LHB). The amount and composition of the volatile fraction influences the outgassing of the Earth mantle during the last planetary formation period. A very weakened form of outgassing activity can still be observed today by examining the composition of volcanic gasses. An enlightenment of the second process is based on the sparse records of the LHB impactors resulting from the composition of meteorites, observed cometary comas, and the impact material found on the Moon. However, for an assessment of the influence of the outgassing on the one hand and the LHB event on the other, one has to supplement the observations with numerical simulations of the formation of volatiles and their incorporation into the accretion material which is the precursors of planetary matter, comets and asteroids. These simulations are performed with a combined hydrodynamic-chemical model of the solar nebula (SN). We calculate the chemical composition of the gas and dust phase of the SN. From these data, we draw conclusions on the upper limits of the water content and the amount of carbon and nitrogen rich volatiles incorporated later into the accretion material. Knowing these limits we determine the portion of major gas compounds delivered during the LHB and compare it with the related quantities of the outgassed species.

  17. Reactive Atmospheric Plasma Spraying of AlN Coatings: Influence of Aluminum Feedstock Particle Size

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2011-03-01

    Feedstock powder characteristics (size distribution, morphology, shape, specific mass, and injection rate) are considered to be one of the key factors in controlling plasma-sprayed coatings microstructure and properties. The influence of feedstock powder characteristics to control the reaction and coatings microstructure in reactive plasma spraying process (RPS) is still unclear. This study, investigated the influence of feedstock particle size in RPS of aluminum nitride (AlN) coatings, through plasma nitriding of aluminum (Al) feedstock powders. It was possible to fabricate AlN-based coatings through plasma nitriding of all kinds of Al powders in atmospheric plasma spray (APS) process. The nitriding ratio was improved with decreasing the particle size of feedstock powder, due to improving the nitriding reaction during flight. However, decreasing the particle size of feedstock powder suppressed the coatings thickness. Due to the loss of the powder during the injection, the excessive vaporization of fine Al particles and the completing nitriding reaction of some fine Al particles during flight. The feedstock particle size directly affects on the nitriding, melting, flowability, and the vaporization behaviors of Al powders during spraying. It concluded that using smaller particle size powders is useful for improving the nitriding ratio and not suitable for fabrication thick AlN coatings in reactive plasma spray process. To fabricate thick AlN coatings through RPS, enhancing the nitriding reaction of Al powders with large particle size during spraying is required.

  18. A Study on the Influence of the Land Surface Processes on the Southwest Monsoon Simulations using a Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Srinivas, C. V.; Bhaskar Rao, D. V.; Hari Prasad, D.; Hari Prasad, K. B. R. R.; Baskaran, R.; Venkatraman, B.

    2015-10-01

    Influence of the land surface processes as an important mechanism in the development of the Indian Summer Monsoon is studied by performing simulations with a regional atmospheric model. Seasonal scale simulations are conducted for two contrasting summer monsoons (MJJAS months) in 2008 & 2009 with the Weather Research and Forecasting-Advanced Research regional model at a high resolution of 15 km using the boundary conditions derived from the National Centers for Environmental Prediction (NCEP) reanalysis data and using the NOAH land surface parameterization scheme. Simulations are evaluated by comparison of precipitation with 0.5° India Meteorological Department gridded rainfall data over land, atmospheric circulation fields with 1° resolution NCEP global final analysis, and surface fluxes with 0.75° resolution Era-Interim reanalysis. Results indicated significant variation in the evolution of the surface fluxes, air temperatures and flux convergence in the 2 contrasting years. A lower albedo, higher heating (sensible, latent heat fluxes), higher air temperatures, stronger flow and higher moisture flux convergence are noted over the subcontinent during the monsoon 2008 relative to the monsoon 2009. The simulated surface fluxes are in good comparison with observations. The stronger flow in 2008 is found to be associated with stronger heat flux gradients as well as stronger north-south geopotential/pressure gradients. The simulations revealed notable differences in many features such as zonal and meridional surface sensible heat gradients which, in turn, influenced the low-level pressure gradients, wind flow, and moisture transport. The present study reveals that, even at a regional scale, the physical processes of land-surface energy partitioning do influence the regional behavior of the monsoon system to a certain extent.

  19. R and D -- Seismic report on the influence of the source region on regional seismic waveforms as inferred from modeling

    SciTech Connect

    App, F.N.; Jones, E.M.; Bos, R.J.

    1997-11-01

    The identification of an underground nuclear test from its seismic signal recorded by seismometers at regional distances is one of the fundamental scientific goals of the Comprehensive Test Ban Treaty R and D Program. The work being reported here addresses the issue of event discrimination through the use of computer models that use realistic simulations of nuclear explosions in various settings for the generation of near-regional and regional synthetic seismograms. The study exercises some unique, recently developed computer modeling capabilities that heretofore have not been available for discrimination studies. A variety of source conditions and regional paths are investigated. Under the assumptions of the study, conclusions are: (1) spall, non-linear deformation, and depth-of-burial do not substantially influence the near-regional signal and (2) effects due to basins along the regional path very much dominate over source region geology in influencing the signal at regional distances. These conclusions, however, are relevant only for the frequencies addressed, which span the range from 0.1 to 1 Hz for the regional calculations and 0.1 to 3 Hz for the near-regional calculations. They also are relevant only for the crudely ``China-like`` basin, crust, and mantle properties used in the study. If it is determined that further investigations are required, researchers may use this study as a template for such work.

  20. Evaluation of size segregation of elemental carbon emission in Europe: influence on atmospheric long-range transportation

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Cheng, Y. F.; Nordmann, S.; Birmili, W.; Denier van der Gon, H. A. C.; Ma, N.; Wolke, R.; Wehner, B.; Sun, J.; Spindler, G.; Mu, Q.; Pöschl, U.; Su, H.; Wiedensohler, A.

    2015-11-01

    Elemental Carbon (EC) has significant impact on human health and climate change. In order to evaluate the size segregation of EC emission and investigation of its influence on atmospheric transport processes in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number/mass size distributions were evaluated by observations taken at the central European background site Melpitz. The fine mode aerosol was reasonably well simulated, but the coarse mode was substantially overestimated by the model. We found that it was mainly due to the nearby point source plume emitting a high amount of EC in the coarse mode. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that coarse mode EC (ECc) emission in the nearby point sources might be overestimated by a factor of 2-10. The emission fraction of EC in coarse mode was overestimated by about 10-30 % for Russian and 5-10 % for Eastern Europe (e.g.: Poland and Belarus), respectively. This overestimation in ECc emission fraction makes EC particles having less opportunity to accumulate in the atmosphere and participate to the long range transport, due to the shorter lifetime of coarse mode aerosol. The deposition concept model showed that the transported EC mass from Warsaw and Moskva to Melpitz may be reduced by 25-35 and 25-55 % respectively, due to the overestimation of ECc emission fraction. This may partly explain the underestimation of EC concentrations for Germany under eastern wind pattern in some other modelling research.