Papers by Dr. Sarvan Kumar
Atmospheric Research, Feb 1, 2019
Year-long variability of the fossil fuel and wood burning black carbon components at a rural site... more Year-long variability of the fossil fuel and wood burning black carbon components at a rural site in southern Delhi outskirts.
42nd COSPAR Scientific Assembly, Jul 1, 2018
Advances in Space Research, 2022
Ø The Existence of the ATAL was recognized through CALIOP lidar observa7ons Ø Buildup of enhanc... more Ø The Existence of the ATAL was recognized through CALIOP lidar observa7ons Ø Buildup of enhanced aerosol associated with Asian Summer Monsoon an7cyclone, extending from the E. Med Sea to W. China Ø Extends from top of convec7ve ou]low over much of SE Asia South Atlan7c Anomaly
Advances in Space Research, 2012
The Indo-Gangetic basin (IGB) extends 2000 km in length along NW-SE and has 400 km width, in the ... more The Indo-Gangetic basin (IGB) extends 2000 km in length along NW-SE and has 400 km width, in the north the basin is bounded by towering Himalaya. High aerosol optical depth (AOD) is observed over the IGB throughout the year. The Himalaya restricts the transport of aerosols across Tibet and China. We have used ground based Kanpur and Gandhi College Aerosol Robotic Network (AERON-ET) stations and Multiangle Imaging SpectroRadiometer (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS) Terra level-3 AOD products for the years 2005-2009 to study the variability of aerosol over the Indo-Gangetic (IG) plains. An increase in both satellite-derived as well as ground observed aerosol loading during 2005-2009 has been found over major cities located in the IG plains. The correlation coefficients between AERONET and MISR data are found to be 0.70, 0.36 0.82, in contrast the correlation coefficients between AERONET and MODIS 0.49, 0.68, and 0.43, respectively during summer, winter and monsoon seasons. The AOD estimation using MISR is found to be close to AERONET data during summer and monsoon seasons, in contrast MODIS estimation is better during winter season.
Atmospheric aerosol consists of both natural and anthropogenic origin. Studies have shown that co... more Atmospheric aerosol consists of both natural and anthropogenic origin. Studies have shown that continuous exposure to these particles is associated with a high percentage of death from respiratory and cardiovascular disease. In the present study, we have first time used both SEM-EDX analysis as well as chemical analysis to understand the differences in morphology and elemental composition of aerosols sample from a suburban clean and green area of Banaras Hindu University campus and some much polluted urban areas of the Varanasi city situated in the eastern Indo-Gangetic plain. The analysis was done by using scanning electron microscope (SEM) coupled with energy dispersive X-ray microanalyzer (EDX) and ionchromatography (IC). Analyses show that C, Ca, Na, S, Si, Al have dominated the samples. The concentration for urban areas of city were more than the pollution of suburban area and followed the trend as Na + > SO 4 2-> Ca 2+ > Cl-> Mg 2+ > NO 3-> K + > HCO 3 + > F-, where as for suburban area showed the trend as Na + > SO 4 2-> NO 3-> Ca 2+ > Cl-> Mg 2+ > K + > HCO 3 + > F-. This shows that more polluted urban areas were dominated by soil-dust generated due to heavy traffic movement and construction/industries. To establish differences among sites more measurements are necessary in different meteorological conditions.
Journal of Geophysical Research: Atmospheres, 2014
Aerosol emissions from biomass burning are of specific interest over the globe due to their stron... more 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 mass trajectories originating from the biomass-burning source region over Punjab at 500 m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD 500 nm > 1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM 2.5) concentrations (>100-150 μgm À3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5) and NO 2 concentrations (~6 × 10 15 mol/cm 2), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the distance from the aerosol source, urban influence, and local characteristics. Local and regional meteorology (air temperature, wind speed, and prolonged droughts) plays a crucial role in the ignition and spread of forest fires, while agricultural burning is commonly practiced by the farmers in developing countries to improve the nutrition level in the soil and agricultural productivity. In Asia, three types KASKAOUTIS ET AL.
Science of The Total Environment
Atmospheric Pollution Research
The novel Coronavirus (2019-nCoV) was identified in Wuhan, Hubei Province, China, in December 201... more The novel Coronavirus (2019-nCoV) was identified in Wuhan, Hubei Province, China, in December 2019 and has created a medical emergency worldwide. It has spread rapidly to multiple countries and has been declared a pandemic by the World Health Organization. In India, it is already reported more than 18 thousand cases and more than 600 deaths due to Coronavirus disease 2019 (COVID-19) till April 20, 2020. Previous studies on various viral infections like influenza have supported an epidemiological hypothesis that the cold and dry (low absolute humidity) environments favor the survival and spread of droplet-mediated viral diseases. These viral transmissions found attenuated in warm and humid (high absolute humidity) environments. However, the role of temperature, humidity, and absolute humidity in the transmission of COVID-19 has not yet been well established. Therefore the study to investigate the meteorological condition for incidence and spread of COVID-19 infection, to predict the ...
International Journal of Remote Sensing
International Journal of Environmental Research and Public Health
The tropospheric NO2 concentration from OMI AURA always shows high concentrations of NO2 at a few... more The tropospheric NO2 concentration from OMI AURA always shows high concentrations of NO2 at a few locations in India, one of the high concentrations of NO2 hotspots is associated with the locations of seven coal-fired Thermal Power plants (TPPs) in Singrauli. Emissions from TPPs are among the major sources of black carbon (BC) soot in the atmosphere. Knowledge of BC emissions from TPPs is important in characterizing regional carbonaceous particulate emissions, understanding the fog/haze/smog formation, evaluating regional climate forcing, modeling aerosol optical parameters and concentrations of black carbon, and evaluating human health. Furthermore, elevated BC concentrations, over the Indo-Gangetic Plain (IGP) and the Himalayan foothills, have emerged as an important subject to estimate the effects of deposition and atmospheric warming of BC on the accelerated melting of snow and glaciers in the Himalaya. For the first time, this study reports BC concentrations and aerosol optical...
ABSTRACT Satellite aerosol data provide good temporal sampling and superior spatial coverage rela... more ABSTRACT Satellite aerosol data provide good temporal sampling and superior spatial coverage relative to ground based station, especially over the Indian subcontinent. We have used ground based Kanpur Aerosol Robotic Network (AERONET) station, Multi-angle Imaging SpectroRadiome-ter (MISR) and Moderate Resolution Imaging Spectroradiometer (MODIS) Terra level-3 AOD product for year 2005-09 to study the variability of aerosol over the Indo-Gangetic plain. An increase in both satellite-derived as well as ground observed aerosol loading over the 2005-2009 time periods has been found over major cities located in the IG basin. We have computed the correlation between MODIS and AERONET AOD during the 2005-2009; also we have computed the correlation between MODIS and MISR AOD for same year. The correlation coefficients between AERONET-MODIS and MISR-MODIS for season winter, summer and monsoon are 0.68, 0.49, 0.43 and 0.82, 0.48., 0.38 respectively for Kanpur. We have also dis-cussed the effect of humidity and rain fall over the Aerosol loading for Kanpur during year 2005-2009. Key words: Aerosol, MISR, MODIS, AERONET, Indo-Gangetic plain.
Journal of Atmospheric and Solar-Terrestrial Physics, 2015
Aeolian Research, 2015
ABSTRACT During the pre-monsoon season (April – June), the Indo-Gangetic Basin (IGB) suffers from... more ABSTRACT During the pre-monsoon season (April – June), the Indo-Gangetic Basin (IGB) suffers from frequent and intense dust storms originated from the arid and desert regions of southwest Asia (Iran, Afghanistan), Arabia and Thar desert blanketing IGB and Himalayan foothills. The present study examines the columnar and vertical aerosol characteristics and estimates the shortwave (0.25-4.0 µm) aerosol radiative forcing (ARF) and atmospheric heating rates over Kanpur, central IGB, during three intense dust-storm events in the pre-monsoon season of 2010. MODIS images, meteorological and AERONET observations clearly show that all the dust storms either originated from the Thar desert or transported over, under favorable meteorological conditions (low pressure and strong surface winds) affecting nearly the whole IGB and modifying the aerosol loading and characteristics (Angstrom exponent, single scattering albedo, size distribution and refractive index). CALIPSO observations reveal the presence of high-altitude (up to 3-5 km) dust plumes that strongly modify the vertical aerosol profile and are transported over Himalayan foothills with serious climate implications (atmospheric warming, enhanced melting of glaciers). Shortwave ARF calculations over Kanpur using SBDART model show large negative forcing values at the surface (-93.27, -101.60 and -66.71 Wm-2) during the intense dusty days, associated with planetary (Top of Atmosphere) cooling (-18.16, -40.95, -29.58 Wm-2) and significant atmospheric heating (75.11, 60.65, 37.13 Wm-2), which is translated to average heating rates of 1.57, 1.41 and 0.78 Kday-1, respectively in the lower atmosphere (below ~3.5 km). The ARF estimates are in satisfactory agreement with the AERONET ARF retrievals over Kanpur.
Atmospheric Research, 2014
The effect of solar variability parameters (solar flux (F 10.7 cm), cosmic ray flux, sunspot numb... more The effect of solar variability parameters (solar flux (F 10.7 cm), cosmic ray flux, sunspot numbers) and meteorological parameters on convective rainfall and lightning flashes in four different Indian regions of equal area is studied. Regions are selected having different topological, vegetation, proximity with ocean and habitat features. Solar variability shows statistically insignificant effect on lightning flash and convective rainfall. The seasonal variation of lightning flashes and convective rainfall in each region could be explained considering the variation of CAPE and surface temperature in that region. The dependence of lightning flashes and convective rainfall on meteorological parameters varies from region to region, as is evident from correlation studies. Lightning flashes is well correlated (R = 0.81) with CAPE in region R 1 and barely correlated (R = 0.23, 0.24) in region R 3 and R 4 whereas rainfall is well correlated (R N 0.68) in all the regions. Lightning flashes are better correlated (R N 0.57) with temperature in R 1 , R 2 and R 4 and moderately correlated in R 3 (R = 0.44). Rainfall in R 3 is very well correlated (R = 0.91) with surface temperature and there is insignificant correlation in R 1 (R = 0.09). There is very good positive correlation (R N 0.59) between cloud cover and convective rainfall in the entire region and well negative correlation (−0.83 b R b −0.61) between OLR and convective rainfall. OLR and cloud cover show little impact on lightning flashes. Lightning flashes and convective rainfall show average positive correlation (0.48 b R b 0.53). Aerosol concentration is the largest in region R 4 and showed an increasing trend between 2007 and 2011. Lightning flashes and convective rainfall are positively correlated (0.10 b R b 0.58) with aerosol concentration.
Annales Geophysicae, 2009
The influence of wind and humidity on aerosol optical depth (AOD) over the Arabian sea is being i... more The influence of wind and humidity on aerosol optical depth (AOD) over the Arabian sea is being investigated using MODIS (Moderate Resolution Imaging Spectroradiometer) Level 3 (Collection-5) and NCEP (National Centres for Environmental Prediction) reanalysis data for the second phase of the Arabian Sea Monsoon Experiment (ARMEX-II) over the South East Arabian Sea (SEAS) in the pre-monsoon period (14 March-10 April 2003). In order to qualify MODIS data for this study, MODIS aerosol parameters were first compared with ship borne Microtops measurements. This showed correlations 0.96-0.97 in the case of spectral AODs and a correlation 0.72 for the angstrom exponents. The daily AOD data from MODIS and winds from NCEP reveal that the ship observed episodic enhancement and decay of AOD at the TSL (Time Series Location) during 23 March-6 April 2003 was caused by the southward drift of an aerosol pocket driven by an intensification and reduction of surface pressure in the North Western Arabian Sea with a low altitude convergence prevailing over SEAS. The AOD increase coincided with a decrease in the Angstrom exponent and the fine mode fraction suggesting the pocket being dominated by coarse mode particles. A partial correlation analysis reveals that the lower altitude wind convergence is the most influential atmospheric variable in modulating AOD over the ARMEX-II domain during the TSL period. However, surface winds at a distant zone in the north/north west upwind direction also had a moderate influence, though with a lag of two days. But this effect was minor since the winds were not strong enough to produce marine aerosols matching with the high AODs over the ARMEX-II domain. These findings and the similarity between MODIS column mass concentration and the ship borne QCM (Quartz Crystal Microbalance) measured coarse mode mass concentration, suggest that the Correspondence to: M. Mohan (mannil [email protected]) aerosol pocket was mostly composed of coarse mode mineral dust in the lower atmospheric altitudes transported from the Arabian deserts.
Aerosol emissions from biomass burning are of specific interest over the globe due to their stron... more 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 mass trajectories originating
from the biomass-burning source region over Punjab at 500m reveal a potential aerosol transport pathway
along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient.
Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence
central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased
number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres
(AOD500 nm>1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5)
concentrations (>100–150 μgm3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5)
and NO2 concentrations (~6 × 1015mol/cm2), indicating the dominance of smoke aerosols from agricultural crop
residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase
in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of
the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol
properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the
distance from the aerosol source, urban influence, and local characteristics.
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Papers by Dr. Sarvan Kumar
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 mass trajectories originating
from the biomass-burning source region over Punjab at 500m reveal a potential aerosol transport pathway
along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient.
Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence
central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased
number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres
(AOD500 nm>1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5)
concentrations (>100–150 μgm3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5)
and NO2 concentrations (~6 × 1015mol/cm2), indicating the dominance of smoke aerosols from agricultural crop
residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase
in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of
the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol
properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the
distance from the aerosol source, urban influence, and local characteristics.
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 mass trajectories originating
from the biomass-burning source region over Punjab at 500m reveal a potential aerosol transport pathway
along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient.
Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence
central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased
number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres
(AOD500 nm>1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5)
concentrations (>100–150 μgm3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5)
and NO2 concentrations (~6 × 1015mol/cm2), indicating the dominance of smoke aerosols from agricultural crop
residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase
in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of
the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol
properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the
distance from the aerosol source, urban influence, and local characteristics.