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Articles 241 - 270 of 294

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Assessing Optimal Set Of Implemental Physical Parameterization Schemes In A Multi-Physics Land Surface Model Using Genetic Algorithm, S. Hong, X. Yu, S. K. Park, Y.-S. Choi, Boksoon Myoung Jan 2014

Assessing Optimal Set Of Implemental Physical Parameterization Schemes In A Multi-Physics Land Surface Model Using Genetic Algorithm, S. Hong, X. Yu, S. K. Park, Y.-S. Choi, Boksoon Myoung

Mathematics, Physics, and Computer Science Faculty Articles and Research

Optimization of land surface models has been challenging due to the model complexity and uncertainty. In this study, we performed scheme-based model optimizations by designing a framework for coupling "the micro-genetic algorithm" (micro-GA) and "the Noah land surface model with multiple physics options" (Noah-MP). Micro-GA controls the scheme selections among eight different land surface parameterization categories, each containing 2–4 schemes, in Noah-MP in order to extract the optimal scheme combination that achieves the best skill score. This coupling framework was successfully applied to the optimizations of evapotranspiration and runoff simulations in terms of surface water balance over the Han River …

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Horizontal Divergence Of Typhoon-Generated Gravity Waves In The Upper Troposphere And Lower Stratosphere (Utls) And Its Influence On Typhoon Evolution, Seung Hee Kim, H.-Y. Chun, W. Jang Jan 2014

Horizontal Divergence Of Typhoon-Generated Gravity Waves In The Upper Troposphere And Lower Stratosphere (Utls) And Its Influence On Typhoon Evolution, Seung Hee Kim, H.-Y. Chun, W. Jang

Mathematics, Physics, and Computer Science Faculty Articles and Research

The characteristics of horizontal divergence induced by typhoon-generated gravity waves (HDTGWs) and the influence of HDTGW on typhoon evolution are investigated based on the simulation results of Typhoon Saomai (2006) using the Weather Research and Forecasting (WRF) model. The power spectral density of HDTGW shows dominant powers at horizontal wavelengths of 20-30 km and at periods of less than 1 h. This is associated with gravity waves generated by vigorous convective clouds in an inner core region of the typhoon. However, the domain-averaged HDTGW in the upper troposphere and lower stratosphere had a spectral peak at 24 h, which is …

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Effects Of Crop Residue Burning On Aerosol Properties, Plume Characteristics, And Long-Range Transport Over Northern India, D. G. Kaskaoutis, S. Kumar, D. Sharma, Ramesh P. Singh, S. K. Kharol, M. Sharma, A. K. Singh, Atinderpal Singh, D. Singh Jan 2014

Effects Of Crop Residue Burning On Aerosol Properties, Plume Characteristics, And Long-Range Transport Over Northern India, D. G. Kaskaoutis, S. Kumar, D. Sharma, Ramesh P. Singh, S. K. Kharol, M. Sharma, A. K. Singh, Atinderpal Singh, D. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air …

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Numerical Simulation Of “An American Haboob”, A. Vukovic, M. Vujadinovic, G. Pejanovic, J. Andric, M. J. Kumjian, V. Djurdjevic, M. Dacic, Anup K. Prasad, Hesham El-Askary, B. C. Paris, S. Petkovic, W. Sprigg, S. Nickovic Jan 2014

Numerical Simulation Of “An American Haboob”, A. Vukovic, M. Vujadinovic, G. Pejanovic, J. Andric, M. J. Kumjian, V. Djurdjevic, M. Dacic, Anup K. Prasad, Hesham El-Askary, B. C. Paris, S. Petkovic, W. Sprigg, S. Nickovic

Mathematics, Physics, and Computer Science Faculty Articles and Research

A dust storm of fearful proportions hit Phoenix in the early evening hours of 5 July 2011. This storm, an American haboob, was predicted hours in advance because numerical, land–atmosphere modeling, computing power and remote sensing of dust events have improved greatly over the past decade. High-resolution numerical models are required for accurate simulation of the small scales of the haboob process, with high velocity surface winds produced by strong convection and severe downbursts. Dust productive areas in this region consist mainly of agricultural fields, with soil surfaces disturbed by plowing and tracks of land in the high Sonoran Desert …

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Long-Term (1951-2007) Rainfall Trends Around Six Indian Cities: Current State, Meteorological, And Urban Dynamics, Shailesh Kumar Kharol, D. G. Kaskaoutis, Anu Rani Sharma, Ramesh P. Singh Jan 2013

Long-Term (1951-2007) Rainfall Trends Around Six Indian Cities: Current State, Meteorological, And Urban Dynamics, Shailesh Kumar Kharol, D. G. Kaskaoutis, Anu Rani Sharma, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

The present study focuses on analyzing the precipitation trends over six Indian cities during the summer monsoon (June-September) covering the period 1951-2007 and also attempting to investigate possible urban forcing and dynamics by examining the variation in precipitation in the upwind and downwind directions. The analysis shows negative trends in the total number of rainy days over Hyderabad (-10.4%), Kanpur (-7.1%), Jaipur (-10.5%), and Nagpur (-4.8%) and positive trends over Delhi (7.4%) and Bangalore (22.9%). On the other hand, decreases of -21.3%, -5.9%, -14.2%, and -14.6% in seasonal rainfall are found over Delhi, Hyderabad, Jaipur, and Kanpur, respectively, whereas Bangalore …

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Inter- And Intra-Annual Variability Of Vegetation In The Northern Hemisphere And Its Association With Precursory Meteorological Factors, Boksoon Myoung, Yong-Sang Choi, Seungbum Hong, Seon Ki Park Jan 2013

Inter- And Intra-Annual Variability Of Vegetation In The Northern Hemisphere And Its Association With Precursory Meteorological Factors, Boksoon Myoung, Yong-Sang Choi, Seungbum Hong, Seon Ki Park

Mathematics, Physics, and Computer Science Faculty Articles and Research

Determination of phenological variation is one of the most critical challenges in dynamic vegetation modeling, given the lack of a strong theoretical framework. Previous studies generally focused on the timing of a phenological event (e.g., bud-burst or onset of growing season) and its atmospheric prompts, but not on the interactive variations across phenological stages. This study, therefore, investigated the inter- and intra-annual variability existing in all the phenological stages and the relations of the variability with four meteorological variables (surface temperature (Ts), shortwave radiation (SW ), vapor pressure deficit (VPD), and precipitation (PRCP)) using a 25-year (1982-2006) dataset of leaf …

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Air-Sea Dimethylsulfide (Dms) Gas Transfer In The North Atlantic: Evidence For Limited Interfacial Gas Exchange At High Wind Speed, T. G. Bell, Warren J. De Bruyn, S. D. Miller, B. Ward, K. Christensen, E. S. Saltzman Jan 2013

Air-Sea Dimethylsulfide (Dms) Gas Transfer In The North Atlantic: Evidence For Limited Interfacial Gas Exchange At High Wind Speed, T. G. Bell, Warren J. De Bruyn, S. D. Miller, B. Ward, K. Christensen, E. S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k(660)) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s(-1). At higher wind speeds the relationship between k(660) and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent …

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Annual Patterns Of Atmospheric Pollutions And Episodes Over Cairo Egypt, Y. Aboel Fetouh, Hesham El-Askary, Mohamed El Raey, Mohamed Allali, W. A. Sprigg, Menas Kafatos Jan 2013

Annual Patterns Of Atmospheric Pollutions And Episodes Over Cairo Egypt, Y. Aboel Fetouh, Hesham El-Askary, Mohamed El Raey, Mohamed Allali, W. A. Sprigg, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Nile Delta major cities, particularly Cairo, experienced stagnant air pollution episodes, known as Black Cloud, every year over the past decade during autumn. Low-elevated thermal inversion layers play a crucial role in intensifying pollution impacts. Carbon monoxide, ozone, atmospheric temperature, water vapor, and methane measurements from the tropospheric emission spectrometer (TES) on board the Aura have been used to assess the dominant component below the inversion layer. In this study, time series analysis, autocorrelations, and cross correlations are performed to gain a better understanding of the connections between those parameters and their local effect. Satellite-based data were obtained for …

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Assessing Satellite-Based Rainfall Estimates In Semiarid Watersheds Using The Usda-Ars Walnut Gulch Gauge Network And Trmm Pr, Eyal Amitai, Carl L. Unkrich, David C. Goodrich, Emad Habib, Bryson Thill Jan 2012

Assessing Satellite-Based Rainfall Estimates In Semiarid Watersheds Using The Usda-Ars Walnut Gulch Gauge Network And Trmm Pr, Eyal Amitai, Carl L. Unkrich, David C. Goodrich, Emad Habib, Bryson Thill

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The rain gauge network associated with the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona provides a unique opportunity for direct comparisons of in situ measurements and satellite-based instantaneous rain rate estimates like those from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR). The WGEW network is the densest rain gauge network in the PR coverage area for watersheds greater than 10 km(2). It consists of 88 weighing rain gauges within a 149-km(2) area. On average, approximately 10 gauges can be found in each PR field of view (similar to 5-km diameter). All gauges are very well synchronized with …

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Toward A Framework For Systematic Error Modeling Of Spaceborne Precipitation Radar With Noaa/Nssl Ground Radar Based National Mosaic Qpe, Pierre-Emmanuel Kirstetter, Y. Hong, J. J. Gourley, S. Chen, Z. Flamig, J. Zhang, M. Schwaller, W. Peterson, Eyal Amitai Jan 2012

Toward A Framework For Systematic Error Modeling Of Spaceborne Precipitation Radar With Noaa/Nssl Ground Radar Based National Mosaic Qpe, Pierre-Emmanuel Kirstetter, Y. Hong, J. J. Gourley, S. Chen, Z. Flamig, J. Zhang, M. Schwaller, W. Peterson, Eyal Amitai

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Characterization of the error associated with satellite rainfall estimates is a necessary component of deterministic and probabilistic frameworks involving spaceborne passive and active microwave measurements for applications ranging from water budget studies to forecasting natural hazards related to extreme rainfall events. The authors focus here on the error structure of NASA's Tropical Rainfall Measurement Mission (TRMM) Precipitation Radar (PR) quantitative precipitation estimation (QPE) at ground. The problem is addressed by comparison of PR QPEs with reference values derived from ground-based measurements using NOAA/NSSL ground radar based National Mosaic and QPE system (NMQ/Q2). A preliminary investigation of this subject has been …

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Synergistic Use Of Remote Sensing And Modeling For Tracing Dust Storms In The Mediterranean, D. G. Kaskaoutis, Anup K. Prasad, P. G. Kosmopoulos, P. R. Sinha, S. K. Kharol, P. Gupta, Hesham El-Askary, Menas Kafatos Jan 2012

Synergistic Use Of Remote Sensing And Modeling For Tracing Dust Storms In The Mediterranean, D. G. Kaskaoutis, Anup K. Prasad, P. G. Kosmopoulos, P. R. Sinha, S. K. Kharol, P. Gupta, Hesham El-Askary, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

This study focuses on the detection of the dust source region and monitoring of the transport of the dust plume from its primary outflow to final deposition. The application area is the Sahara desert and the eastern Mediterranean, where two dust events occurred during the period 4–6 February 2009, an unusual event for a winter period. The Aqua-MODIS and OMI observations clearly define the spatial distribution of the dust plumes, while the CALIPSO observations of total attenuated backscatter (TAB) at 532 nm, depolarization ratio (DR), and attenuated color ratio (1064/532 nm) on 5 February 2009 provide a clear view and …

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Fog- And Cloud-Induced Aerosol Modification Observed By The Aerosol Robotic Network (Aeronet), T. F. Eck, B. N. Holben, J. S. Reid, D. M. Giles, M. A. Rivas, Ramesh P. Singh, S. N. Tripathi, C. J. Bruegge, S. Platnick, G. T. Arnold, N. A. Krotkov, S. A. Carn, A. Sinyuk, O. Dubovik, A. Arola, J. S. Schafer, P. Artaxo, A. Smirnov, H. Chen, P. Goloub Jan 2012

Fog- And Cloud-Induced Aerosol Modification Observed By The Aerosol Robotic Network (Aeronet), T. F. Eck, B. N. Holben, J. S. Reid, D. M. Giles, M. A. Rivas, Ramesh P. Singh, S. N. Tripathi, C. J. Bruegge, S. Platnick, G. T. Arnold, N. A. Krotkov, S. A. Carn, A. Sinyuk, O. Dubovik, A. Arola, J. S. Schafer, P. Artaxo, A. Smirnov, H. Chen, P. Goloub

Mathematics, Physics, and Computer Science Faculty Articles and Research

Large fine mode-dominated aerosols (submicron radius) in size distributions retrieved from the Aerosol Robotic Network (AERONET) have been observed after fog or low-altitude cloud dissipation events. These column-integrated size distributions have been obtained at several sites in many regions of the world, typically after evaporation of low-altitude cloud such as stratocumulus or fog. Retrievals with cloud-processed aerosol are sometimes bimodal in the accumulation mode with the larger-size mode often similar to 0.4-0.5 mu m radius (volume distribution); the smaller mode, typically similar to 0.12 to similar to 0.20 mu m, may be interstitial aerosol that were not modified by incorporation …

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Impact Of Vegetation On Land-Atmosphere Coupling Strength And Its Implication For Desertification Mitigation Over East Asia, Boksoon Myoung, Yong-Sang Choi, Suk-Jin Choi, Seon Ki Park Jan 2012

Impact Of Vegetation On Land-Atmosphere Coupling Strength And Its Implication For Desertification Mitigation Over East Asia, Boksoon Myoung, Yong-Sang Choi, Suk-Jin Choi, Seon Ki Park

Mathematics, Physics, and Computer Science Faculty Articles and Research

Desertification of the East Asian drylands and the consequent dust transport have been serious concerns for adjacent Asian countries as well as the western United States. Tree planting has been considered one applicable strategy to mitigate the desertification. However, the desired effect of the tree planting would not be brought to fruition unless the newly planted trees change the coupling characteristics between the land and the atmosphere. Based on this perception, we attempt to clarify the effects of vegetation on the coupling strength between the atmosphere and land surface, and we suggest the most efficient areas of tree planting for …

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Variability And Trends Of Aerosol Properties Over Kanpur, Northern India Using Aeronet Data (2001–10), Dimitris G. Kaskaoutis, Ramesh P. Singh, Ritesh Gautam, Manish Sharma, P. G. Kosmopoulos, S. N. Tripathi Jan 2012

Variability And Trends Of Aerosol Properties Over Kanpur, Northern India Using Aeronet Data (2001–10), Dimitris G. Kaskaoutis, Ramesh P. Singh, Ritesh Gautam, Manish Sharma, P. G. Kosmopoulos, S. N. Tripathi

Mathematics, Physics, and Computer Science Faculty Articles and Research

Natural and anthropogenic aerosols over northern India play an important role in influencing the regional radiation budget, causing climate implications to the overall hydrological cycle of South Asia. In the context of regional climate change and air quality, we discuss aerosol loading variability and trends at Kanpur AERONET station located in the central part of the Indo-Gangetic plains (IGP), during the last decade (2001-10). Ground-based radiometric measurements show an overall increase in column-integrated aerosol optical depth (AOD) on a yearly basis. This upward trend is mainly due to a sustained increase in the seasonal/monthly averaged AOD during the winter (Dec-Feb) …

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Influence Of Anomalous Dry Conditions On Aerosols Over India: Transport, Distribution And Properties, Dimitris G. Kaskaoutis, Ritesh Gautam, Ramesh P. Singh, E. E. Housos, D. Goto, S. Singh, A. Bartzokas, P. G. Kosmopoulos, Manish Sharma, N. C. Hsu, B. N. Holben, T. Takemura Jan 2012

Influence Of Anomalous Dry Conditions On Aerosols Over India: Transport, Distribution And Properties, Dimitris G. Kaskaoutis, Ritesh Gautam, Ramesh P. Singh, E. E. Housos, D. Goto, S. Singh, A. Bartzokas, P. G. Kosmopoulos, Manish Sharma, N. C. Hsu, B. N. Holben, T. Takemura

Mathematics, Physics, and Computer Science Faculty Articles and Research

A synergy of satellite and ground-based radiometric observations, along with chemical transport modeling, was used for the assessment of the influence of drought monsoon conditions of 2002 and prolonged dry pre-monsoon period of 2003 on aerosol properties over south Asia, with emphasis over northern India. Reanalysis data are also examined for studying the dry anomalous period from the climatological mean, that show prevalence of westerlies under anticyclonic circulation and subsidence favoring the accumulation of aerosols. TRMM observations over south Asia indicate significant rainfall deficit over northwestern India in July 2002 and May-June 2003. Subsequently, the anomalous and prolonged dry conditions …

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Aerosol Properties Over The Indo‐Gangetic Plain: A Mesoscale Perspective From The Tigerz Experiment, D. M. Giles, B. N. Holben, Sachchida N. Tripathi, Thomas F. Eck, W. Wayne Newcomb, Ilya Slutsker, Russell R. Dickerson, Anne M. Thompson, Shana Mattoo, Sheng-Hsiang Wang, Ramesh P. Singh, Aliaksandyr Sinyuk, Joel S. Schafer Jan 2011

Aerosol Properties Over The Indo‐Gangetic Plain: A Mesoscale Perspective From The Tigerz Experiment, D. M. Giles, B. N. Holben, Sachchida N. Tripathi, Thomas F. Eck, W. Wayne Newcomb, Ilya Slutsker, Russell R. Dickerson, Anne M. Thompson, Shana Mattoo, Sheng-Hsiang Wang, Ramesh P. Singh, Aliaksandyr Sinyuk, Joel S. Schafer

Mathematics, Physics, and Computer Science Faculty Articles and Research

High aerosol loading over the northern Indian subcontinent can result in poor air quality leading to human health consequences and climate perturbations. The international 2008 TIGERZ experiment intensive operational period (IOP) was conducted in the Indo-Gangetic Plain (IGP) around the industrial city of Kanpur (26.51 degrees N, 80.23 degrees E), India, during the premonsoon (April-June). Aerosol Robotic Network (AERONET) Sun photometers performed frequent measurements of aerosol properties at temporary sites distributed within an area covering similar to 50 km(2) around Kanpur to characterize pollution and dust in a region where complex aerosol mixtures and semi-bright surface effects complicate satellite retrieval …

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Three-Year Ground Based Measurements Of Aerosol Optical Depth Over The Eastern Mediterranean: The Urban Environment Of Athens, E. Gerasopoulos, V. Amiridis, S. Kazadzis, P. Kokkalis, K. Eleftheratos, M. O. Andrae, T. W. Andrae, Hesham El-Askary, C S. Zerefos Jan 2011

Three-Year Ground Based Measurements Of Aerosol Optical Depth Over The Eastern Mediterranean: The Urban Environment Of Athens, E. Gerasopoulos, V. Amiridis, S. Kazadzis, P. Kokkalis, K. Eleftheratos, M. O. Andrae, T. W. Andrae, Hesham El-Askary, C S. Zerefos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean A° ngstro¨m coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing throughout the day. The greatest contribution …

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Evaluation Of Satellite-Retrieved Extreme Precipitation Rates Across The Central United States, A. Aghakoucak, A. Behrangi, S. Sorooshian, K. Hsu, Eyal Amitai Jan 2011

Evaluation Of Satellite-Retrieved Extreme Precipitation Rates Across The Central United States, A. Aghakoucak, A. Behrangi, S. Sorooshian, K. Hsu, Eyal Amitai

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Water resources management, forecasting, and decision making require reliable estimates of precipitation. Extreme precipitation events are of particular importance because of their severe impact on the economy, the environment, and the society. In recent years, the emergence of various satellite-retrieved precipitation products with high spatial resolutions and global coverage have resulted in new sources of uninterrupted precipitation estimates. However, satellite-based estimates are not well integrated into operational and decision-making applications because of a lack of information regarding the associated uncertainties and reliability of these products. In this study, four satellite-derived precipitation products (CMORPH, PERSIANN, TMPA-RT, and TMPA-V6) are evaluated with …

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Extremely Large Anthropogenic-Aerosol Contribution To Total Aerosol Load Over The Bay Of Bengal During Winter Season, Dimitris G. Kaskaoutis, Shailesh Kumar Kharol, P. R. Sinha, Ramesh P. Singh, H. D. Kambezidis, Anu Rani Sharma, K. V. S. Bardarinath Jan 2011

Extremely Large Anthropogenic-Aerosol Contribution To Total Aerosol Load Over The Bay Of Bengal During Winter Season, Dimitris G. Kaskaoutis, Shailesh Kumar Kharol, P. R. Sinha, Ramesh P. Singh, H. D. Kambezidis, Anu Rani Sharma, K. V. S. Bardarinath

Mathematics, Physics, and Computer Science Faculty Articles and Research

Ship-borne observations of spectral aerosol optical depth (AOD) have been carried out over the entire Bay of Bengal (BoB) as part of the W-ICARB cruise campaign during the period 27 December 2008-30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD(500)> 0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Angstrom exponent is also found …

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Estimation Of Nox Emissions From Delhi Using Car Max-Doas Observations And Comparison With Omi Satellite Data, R. Shaiganfar, S. Beirle, Manish Sharma, A. Chauhan, Ramesh P. Singh, T. Wagner Jan 2011

Estimation Of Nox Emissions From Delhi Using Car Max-Doas Observations And Comparison With Omi Satellite Data, R. Shaiganfar, S. Beirle, Manish Sharma, A. Chauhan, Ramesh P. Singh, T. Wagner

Mathematics, Physics, and Computer Science Faculty Articles and Research

We present the first Multi-Axis-(MAX-) DOAS observations in India performed during April 2010 and January 2011 in Delhi and nearby regions. The MAX-DOAS instrument was mounted on a car roof, which allowed us to perform measurements along individual driving routes. From car MAX-DOAS observations along closed circles around Delhi, together with information on wind speed and direction, the NOx emissions from the greater Delhi area were determined: our estimate of 4.4 x 10(25) molecules s(-1) is found to be slightly lower than the corresponding emission estimates using the EDGAR emission inventory and substantially smaller compared to a recent study by …

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Contrasting Aerosol Trends Over South Asia During The Last Decade Based On Modis Observations, Dimitris G. Kaskaoutis, Shailesh Kumar Kharol, P. R. Sinha, Ramesh P. Singh, K. V. S. Badarinath, Waseem Mehdi, Manish Sharma Jan 2011

Contrasting Aerosol Trends Over South Asia During The Last Decade Based On Modis Observations, Dimitris G. Kaskaoutis, Shailesh Kumar Kharol, P. R. Sinha, Ramesh P. Singh, K. V. S. Badarinath, Waseem Mehdi, Manish Sharma

Mathematics, Physics, and Computer Science Faculty Articles and Research

Atmospheric aerosols over south Asia constitute a major environmental and climate issue. Thus, extensive land and cruise campaigns have been conducted over the area focusing on investigating the aerosol properties and climate implications. Except from the ground-based instrumentation, several studies dealt with analyzing the aerosol properties from space, focusing mainly on the spatial distribution of the aerosol optical depth (AOD) and possible feedbacks of aerosols on the monsoon system. However, except from some works using ground-based instrumentation or satellite observations over a specific region, there is lack of studies dealing with monitoring of the aerosol trend over south Asia. The …

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Aerosol Climatology Over Nile Delta Based On Modis, Misr And Omi Satellite Data, H. S. Marey, J. C. Gille, Hesham El-Askary, E. A. Shalaby, Mohamed El Raey Jan 2011

Aerosol Climatology Over Nile Delta Based On Modis, Misr And Omi Satellite Data, H. S. Marey, J. C. Gille, Hesham El-Askary, E. A. Shalaby, Mohamed El Raey

Mathematics, Physics, and Computer Science Faculty Articles and Research

Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the “black cloud” during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) at 550 nm were examined for the 10 yr period from 2000–2009. Significant monthly variability is observed in the AOD with maxima in April or May (_0.5) and October (_0.45), and a …

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Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman Jan 2010

Post-Coring Entrapment Of Modern Air In Some Shallow Ice Cores Collected Near The Firn-Ice Transition: Evidence From Cfc-12 Measurements In Antarctic Firn Air And Ice Cores, Murat Aydin, S. A. Montzka, M. O. Battle, M. B. Williams, Warren J. De Bruyn, J. H. Butler, K. R. Verhulst, C. Tatum, B. K. Gun, D. A. Plotkin, B. D. Hall, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this study, we report measurements of CFC-12 (CCl2F2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for the presence of modern air entrapped in the shallow ice core samples that likely contained open pores at the time of collection. We propose that this is due to closure of the open pores …

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Climatological Aspects Of The Optical Properties Of Fine/Coarse Mode Aerosol Mixtures, Thomas F. Eck, B. N. Holben, Aliaksandyr Sinyuk, R. T. Pinker, P. Goloub, H. Chen, B. Chatenet, Z. Li, Ramesh P. Singh, Sachchida N. Tripathi, J. S. Reid, D. M. Giles, O. Dubovik, N. T. O'Neill, A. Smirnov, P. Wang, X. Xia Jan 2010

Climatological Aspects Of The Optical Properties Of Fine/Coarse Mode Aerosol Mixtures, Thomas F. Eck, B. N. Holben, Aliaksandyr Sinyuk, R. T. Pinker, P. Goloub, H. Chen, B. Chatenet, Z. Li, Ramesh P. Singh, Sachchida N. Tripathi, J. S. Reid, D. M. Giles, O. Dubovik, N. T. O'Neill, A. Smirnov, P. Wang, X. Xia

Mathematics, Physics, and Computer Science Faculty Articles and Research

Aerosol mixtures composed of coarse mode desert dust combined with fine mode combustion generated aerosols (from fossil fuel and biomass burning sources) were investigated at three locations that are in and/or downwind of major global aerosol emission source regions. Multiyear monitoring data at Aerosol Robotic Network sites in Beijing (central eastern China), Kanpur (Indo-Gangetic Plain, northern India), and Ilorin (Nigeria, Sudanian zone of West Africa) were utilized to study the climatological characteristics of aerosol optical properties. Multiyear climatological averages of spectral single scattering albedo (SSA) versus fine mode fraction (FMF) of aerosol optical depth at 675 nm at all three …

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Complementary Nature Of Surface And Atmospheric Parameters Associated With Haiti Earthquake Of 12 January 2010, Ramesh P. Singh, Waseem Mehdi, Manish Sharma Jan 2010

Complementary Nature Of Surface And Atmospheric Parameters Associated With Haiti Earthquake Of 12 January 2010, Ramesh P. Singh, Waseem Mehdi, Manish Sharma

Mathematics, Physics, and Computer Science Faculty Articles and Research

The present paper describes surface (surface air temperature) and atmospheric parameters (relative humidity, surface latent heat flux) over the epicenter (18A degrees 27A ' 25A ' A ' N 72A degrees 31A ' 59A ' A ' W) of Haiti earthquake of 12 January 2010. Our analysis shows pronounced changes in surface and atmospheric parameters few days prior to the main earthquake event. Changes in relative humidity are found from the surface up to an altitude of 500 hPa clearly show atmospheric perturbations associated with the earthquake event. The purpose of this paper is to show complementary nature of the …

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Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman Jan 2009

Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report the first simultaneous eddy covariance flux measurements of CO2 and dimethylsulfide (DMS) over the open ocean for two North Atlantic cruises. After normalization for Schmidt number, the two gases give essentially identical gas transfer coefficients and wind speed dependences for the wind speed range 2-10 ms(-1). The data indicate a linear relationship between the gas transfer coefficient and mean wind speed, with measured gas transfer coefficients slightly above the Wanninkhof (1992) parameterization, particularly at low wind speeds. Citation: Miller, S., C. Marandino, W. de Bruyn, and E. S. Saltzman (2009), Air-sea gas exchange of CO2 and DMS in …

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A Chemical Ionization Mass Spectrometer For Continuous Underway Shipboard Analysis Of Dimethylsulfide In Near-Surface Seawater, Eric S. Saltzman, Warren J. De Bruyn, M. J. Lawler, Christa Marandino, C. A. Mccormick Jan 2009

A Chemical Ionization Mass Spectrometer For Continuous Underway Shipboard Analysis Of Dimethylsulfide In Near-Surface Seawater, Eric S. Saltzman, Warren J. De Bruyn, M. J. Lawler, Christa Marandino, C. A. Mccormick

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

A compact, low-cost atmospheric pressure, chemical ionization mass spectrometer ('mini-CIMS') has been developed for continuous underway shipboard measurements of dimethylsulfide (DMS) in seawater. The instrument was used to analyze DMS in air equilibrated with flowing seawater across a porous Teflon membrane equilibrator. The equilibrated gas stream was diluted with air containing an isotopically-labeled internal standard. DMS is ionized at atmospheric pressure via proton transfer from water vapor, then declustered, mass filtered via quadrupole mass spectrometry, and detected with an electron multiplier. The instrument described here is based on a low-cost residual gas analyzer (Stanford Research Systems), which has been modified …

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Open Ocean Dms Air/Sea Fluxes Over The Eastern South Pacific Ocean, C. A. Marandino, Warren J. De Bruyn, S. D. Miller, E. S. Saltzman Jan 2009

Open Ocean Dms Air/Sea Fluxes Over The Eastern South Pacific Ocean, C. A. Marandino, Warren J. De Bruyn, S. D. Miller, E. S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Air/sea fluxes of dimethylsulfide (DMS) were measured by eddy correlation over the Eastern South Pacific Ocean during January 2006. The cruise track extended from Manzanillo, Mexico, along 110 degrees W, to Punta Arenas, Chile. Bulk air and surface ocean DMS levels were also measured and gas transfer coefficients (k(DMS)) were computed. Air and seawater DMS measurements were made using chemical ionization mass spectrometry (API-CIMS) and a gas/liquid membrane equilibrator. Mean surface seawater DMS concentrations were 3.8 +/- 2.2 nM and atmospheric mixing ratios were 340 +/- 370 ppt. The air/sea flux of DMS was uniformly out of the ocean, with …

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Numerical Simulations Of The Impacts Of The Saharan Air Layer On Atlantic Tropical Cyclone Development, Donglian Sun, K. M. Lau, Menas Kafatos, Z. Boybeyi, G. Leptoukh, C. Yang, Ruixin Yang Jan 2009

Numerical Simulations Of The Impacts Of The Saharan Air Layer On Atlantic Tropical Cyclone Development, Donglian Sun, K. M. Lau, Menas Kafatos, Z. Boybeyi, G. Leptoukh, C. Yang, Ruixin Yang

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, the role of the Saharan air layer (SAL) is investigated in the development and intensification of tropical cyclones (TCs) via modifying environmental stability and moisture, using multisensor satellite data, long-term TC track and intensity records, dust data, and numerical simulations with a state-of-the-art Weather Research and Forecasting model (WRF). The long-term relationship between dust and Atlantic TC activity shows that dust aerosols are negatively associated with hurricane activity in the Atlantic basin, especially with the major hurricanes in the western Atlantic region. Numerical simulations with the WRF for specific cases during the NASA African Monsoon Multidisciplinary Analyses …

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Two Contrasting Dust-Dominant Periods Over India Observed From Modis And Calipso Data, Ritesh Gautam, Zhaoyan Liu, Ramesh P. Singh, N. Christina Hsu Jan 2009

Two Contrasting Dust-Dominant Periods Over India Observed From Modis And Calipso Data, Ritesh Gautam, Zhaoyan Liu, Ramesh P. Singh, N. Christina Hsu

Mathematics, Physics, and Computer Science Faculty Articles and Research

Each year, prior to the onset of the Indian Summer Monsoon, the Gangetic Plains (GP), bounded by the high-altitude Himalayan mountains, are strongly influenced by the transport of dust outbreaks originating in the northwestern desert in India (known as the Thar Desert). Dust particles constitute the bulk of the regional aerosol loading which peaks annually during the pre-monsoon season. This paper integrates observations from space-borne sensors, namely MODIS and CALIPSO, together with ground sunphotometer measurements, to infer dust loading in the pre-monsoon aerosol build-up over source and sink regions in northern India. Detailed aerosol characterization from the synergetic observational assessment …

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