Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 61 - 90 of 96

Full-Text Articles in Physical Sciences and Mathematics

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 …


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 …


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 …


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 …


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 …


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 …


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 …


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 …


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 …


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) …


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 …


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 …


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 …


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 …


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 …


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 …


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 …


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 …


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 …


Melting Of Major Glaciers In The Western Himalayas: Evidence Of Climatic Changes From Long Term Msu Derived Tropospheric Temperature Trend (1979-2008), Anup K. Prasad, Keun-Hang Susan Yang, Hesham El-Askary, Menas Kafatos Jan 2009

Melting Of Major Glaciers In The Western Himalayas: Evidence Of Climatic Changes From Long Term Msu Derived Tropospheric Temperature Trend (1979-2008), Anup K. Prasad, Keun-Hang Susan Yang, Hesham El-Askary, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Global warming or the increase of the surface and atmospheric temperatures of the Earth, is increasingly discernible in the polar, sub-polar and major land glacial areas. The Himalayan and Tibetan Plateau Glaciers, which are the largest glaciers outside of the Polar regions, are showing a large-scale decrease of snow cover and an extensive glacial retreat. These glaciers such as Siachen and Gangotri are a major water resource for Asia as they feed major rivers such as the Indus, Ganga and Brahmaputra. Due to scarcity of ground measuring stations, the long-term observations of atmospheric temperatures acquired from the Microwave Sounding Unit …


Validation Of Modis Terra, Airs, Ncep/Doe Amip-Ii Reanalysis-2, And Aeronet Sun Photometer Derived Integrated Precipitable Water Vapor Using Ground-Based Gps Receivers Over India, Anup K. Prasad, Ramesh P. Singh Jan 2009

Validation Of Modis Terra, Airs, Ncep/Doe Amip-Ii Reanalysis-2, And Aeronet Sun Photometer Derived Integrated Precipitable Water Vapor Using Ground-Based Gps Receivers Over India, Anup K. Prasad, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Water vapor is an important and highly variable constituent in time and space; the knowledge of its variability is important in climate studies. In India, the ground observations of water vapor using conventional methods such as radiosonde are limited. In this paper, a comparison of hourly estimates of total column water vapor from Global Positioning System (GPS) with multisensor satellite is presented over three stations. We show quantitatively seasonal and monthly dependency of bias, standard deviation, root mean square error (RMSE), and the correlation coefficient between the water vapor data sets. The GPS and Aerosol Robotic Network (AERONET) water vapor …


Inter-Continental Transport Of Dust And Pollution Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos Jan 2009

Inter-Continental Transport Of Dust And Pollution Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, …


Transport Of Dust And Anthropogenic Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos Jan 2009

Transport Of Dust And Anthropogenic Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, …


Enhanced Pre-Monsoon Warming Over The Himalayan-Gangetic Region From 1979-2007, Ritesh Gautam, N. C. Hsu, K. M. Lau, S.-C. Tsay, Menas Kafatos Jan 2009

Enhanced Pre-Monsoon Warming Over The Himalayan-Gangetic Region From 1979-2007, Ritesh Gautam, N. C. Hsu, K. M. Lau, S.-C. Tsay, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Fundamental to the onset of the Indian Summer Monsoon is the land-sea thermal gradient from the Indian Ocean to the Himalayas-Tibetan Plateau (HTP). The timing of the onset is strongly controlled by the meridional tropospheric temperature gradient due to the rapid premonsoon heating of the HTP compared to the relatively cooler Indian Ocean. Analysis of tropospheric temperatures from the longest available record of microwave satellite measurements reveals widespread warming over the Himalayan-Gangetic region and consequent strengthening of the land-sea thermal gradient. This trend is most pronounced in the pre-monsoon season, resulting in a warming of 2.7 C in the 29-year …


The Potential Of The Synergistic Use Of Passive And Active Remote Sensing Measurements For The Validation Of A Regional Dust Model, V. Amiridis, Menas Kafatos, M. Perez, S. Kazadzis, E. Gerasopoulos, R. E. Mamouri, A. Papayannis, P. Kokkalis, E. Giannakaki, S. Basart, I. Daglis, C S. Zerefos Jan 2009

The Potential Of The Synergistic Use Of Passive And Active Remote Sensing Measurements For The Validation Of A Regional Dust Model, V. Amiridis, Menas Kafatos, M. Perez, S. Kazadzis, E. Gerasopoulos, R. E. Mamouri, A. Papayannis, P. Kokkalis, E. Giannakaki, S. Basart, I. Daglis, C S. Zerefos

Mathematics, Physics, and Computer Science Faculty Articles and Research

A long-lasting Saharan dust event affected Europe on 18–23 May 2008. Dust was present in the free troposphere over Greece, in height ranges between the surface and approximately 4–5 km above sea level. The event was monitored by ground-based CIMEL sunphotometric and multi-wavelength combined backscatter/Raman lidar measurements over Athens, Greece. The dust event had the maximum of its intensity on 20 May. Three-dimensional dust spatial distribution over Greece on that day is presented through satellite synergy of passive and active remote sensing using MODIS and CALIPSO data, respectively. For the period under study, the ground-based measurements are used to characterize …


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 …


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 …


Contrasting The 2007 And 2005 Hurricane Seasons: Evidence Of Possible Impacts Of Saharan Dry Air And Dust On Tropical Cyclone Activity In The Atlantic Basin, D. Sun, K. M. Lau, Menas Kafatos Jan 2008

Contrasting The 2007 And 2005 Hurricane Seasons: Evidence Of Possible Impacts Of Saharan Dry Air And Dust On Tropical Cyclone Activity In The Atlantic Basin, D. Sun, K. M. Lau, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we provide preliminary evidence of possible modulation by Saharan dust of hurricane genesis and intensification, by contrasting the 2007 and 2005 hurricane seasons. It is found that dust aerosol loadings over the Atlantic Ocean are much higher in 2007 than in 2005. The temperature difference between 2007 and 2005 shows warming in the low-middle troposphere (900–700 hPa) in the dusty region in the eastern North Atlantic, and cooling in the Main Development Region (MDR). The humidity (wind) differences between 2007 and 2005 indicate significant drying (subsidence) in the Western North Atlantic (WNA) in 2007. The drier air …


A Study Of Land Surface Processes Using Land Surface Models Over The Little River Experimental Watershed, A. K. Sahoo, P. A. Dirmeyer, P. R. Houser, Menas Kafatos Jan 2008

A Study Of Land Surface Processes Using Land Surface Models Over The Little River Experimental Watershed, A. K. Sahoo, P. A. Dirmeyer, P. R. Houser, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Three different land surface models (Hydrological improvements to the Simplified version of the Simple Biosphere model (HySSiB), Noah model, and Community Land Model (CLM)) were simulated on the NASA Goddard Space Flight Center’s Land Information System platform at 1-km resolution over the Little River Experimental Watershed, Georgia, and the simulated results were analyzed to address the local-scale land-atmosphere processes. All the three models simulated the soil moisture in space and time realistically. The Noah model produced higher soil moisture whereas the CLM got lower soil moisture with many dry down phases. CLM and HySSiB models were oversensitive to the atmospheric …


Improved Associated Conditions In Rapid Intensifications Of Tropical Cyclones, Ruixin Yang, J. Tang, Menas Kafatos Jan 2007

Improved Associated Conditions In Rapid Intensifications Of Tropical Cyclones, Ruixin Yang, J. Tang, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Rapid intensification (RI) of tropical cyclones (TC) is a major error source in TC intensity forecasting. In order to improve the estimates of RI probability, association rules are used to facilitate the process of mining for candidate sets of conditions. Compared to the relation analysis method, the technique of association rules can simply explore associations among multiple conditions. Our mining results identified a reduced predictor set with fewer factors identified in previous studies but improved RI probabilities. That is, the RI probability with three conditions satisfied: low vertical shear, high humidity, and the TC being in an intensification phase is …