Dr. Sarvan Kumar
VBS Purvanchal University, Earth and Planetary Sciences, Faculty Member
- Banaras Hindu University, Varanasi, Physics, Graduate Studentadd
- I am an atmospheric Scientist.edit
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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... 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 ...
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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... 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...
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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)... 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.
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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... 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.
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Research Interests:
Research Interests:
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... 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.
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.
Research Interests:
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... 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 sample s. 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
+
> HCO3
+
> F
-, where as for suburban area showed the trend as Na
+
> SO
4
2->
NO3
-> Ca
2+
> Cl
-> Mg
2+
> K
+
> HCO3
+
> 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.
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 sample s. 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
+
> HCO3
+
> F
-, where as for suburban area showed the trend as Na
+
> SO
4
2->
NO3
-> Ca
2+
> Cl
-> Mg
2+
> K
+
> HCO3
+
> 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.