Browsing by Author "Vineet Pratap"

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Analysis of air pollution in the atmosphere due to firecrackers in the Diwali period over an urban Indian region
(Elsevier Ltd, 2021) Vineet Pratap; Upal Saha; Akhilesh Kumar; Abhay K. Singh
Short-term investigations of atmospheric pollutants (PM10, PM2.5, SO2, NO2, O3, and CO) were performed during the Diwali festival over Varanasi for a period of six years from 2011 to 2016. Aerosol Optical Depth (AOD) observed for the corresponding days of Diwali was found to be considerably much higher and even its value reached 2.0 for some Diwali years, which is basically almost 3-folds than the control days. The total scattering aerosol optical thickness as well as aerosol extinction co-efficient at 550 nm crossed the value of 1.0 in almost all the Diwali day cases. The associated meteorological conditions (low wind speed, declining temperature, lowered night-time boundary layer height, etc.) during the Diwali period leads to the detrimental accumulation of atmospheric pollutants near to the surface layer in Varanasi region. Moreover, PM10 and PM2.5 concentrations were recorded much higher than the safer limits set by NAAQS for 24-hour mean values throughout the period of study. The concentrations of PM10 and PM2.5 crossed beyond the safer limits and crossed 500 µg/m3 (in 2015) and 450 µg/m3 (in 2016) respectively, which is basically 5–6 times higher than the standard NAAQS limit. In comparison with the trace gases concentrations (e.g. SO2, NO2, O3, and CO) on control day, it was observed higher on the respective Diwali day. Satellite data derived from MODIS (Aqua and Terra) have also been taken into account to observe and verify the unpropitious effects of fireworks for the chosen case. MODIS true-color images show dense smoke plumes and haze over the entire Indo-Gangetic Plain (IGP) on Diwali days of 2011–2016 with its continuation in the following days. Proper assessment and regular monitoring is needed in order to mitigate the localized air pollution due to this kind of festival by the local scale authority to the top-level environmentalists. © 2021 COSPAR
Assessment of atmospheric aerosols over Varanasi: Physical, optical and chemical properties and meteorological implications
(Elsevier Ltd, 2020) Pradeep Kumar; Vineet Pratap; Akhilesh Kumar; Arti Choudhary; Rajendra Prasad; Anuradha Shukla; R.P. Singh; Abhay Kumar Singh
The present paper reports the results derived from PM2.5 and PM10 concentrations during October 2016–May 2018 using MICROTOPS-II Sunphotometer and high volume samplers at Varanasi. Observed data were categorized and analyzed in order to understand the nature, source of origin and variability with seasons. Observations showed aerosol mass loading during the post-monsoon 2016 and winter 2017 as compared to the pre-monsoon 2018 values, which typically exceed national standard. The close relationships between PM2.5 and PM10 during post-monsoon (r = 0.571) and winter (r = 0.799) suggested that both type of particulates might have originated from the same source. Further, the PM2.5/PM10 indicated that the fine particles were dominantly present during the post-monsoon and winter season where as coarse particles were found dominant in the pre-monsoon season. The measured high values of aerosol optical depth (AOD) and angstrom exponent (AE) during post-monsoon and winter attributed to the accumulation of aerosols from sources and biomass/crop residue burning in the surrounding region and low dispersal due to shallow boundary layer and lower wind velocity. In contrast during pre-monsoon months the aerosols were accumulated as a mixture of transported from deserts and other far away regions including mineral from earth crust. The effect of meteorological parameters (temperature, wind speed and relative humidity) was also studied. Temperature did not show any relation during the pre monsoon when it was quite high, whereas during the winter months it showed negative trend with concentration. Wind showed negative correlation during the whole observation period. Relative humidity showed weak positive correlation during winter months for PM2.5 and PM10 where as PM2.5 did not show any relation during pre and post monsoon. PM10 showed weak negative relation during pre monsoon months. In order to understand elemental and ionic composition Scanning electron microscope (SEM) coupled with energy dispersive X-ray microanalyzer (EDX) analysis were done which showed dominant presence of C, F, O, Si, N, Na, K, Al, Ca and S. The following trend SO42− > NO3− > Na+> Ca2+> K+> Cl− > F− > Mg2+> Li+ was observed from the Ion chromatograph (IC) analysis. The source for these elements may have been different industrial activities, biomass burning and vehicular emissions. The results are useful for further planning of city developments and climate studies. © 2020 Elsevier Ltd
Assessment of equivalent black carbon variations and its source apportionment over Varanasi, Indo-Gangetic Basin
(Elsevier B.V., 2024) Prashant Kumar Chauhan; Shani Tiwari; Dileep Kumar Gupta; Akhilesh Kumar; Vineet Pratap; Abhay Kumar Singh
In this study, the temporal variation of Equivalent Black Carbon (eBC) and its source apportionment is studied using a yearlong (Dec. 2020–Nov. 2021) multiwavelength Aethalometer (AE-33 model) measurements over Varanasi, located in the central Indo-Gangetic Basin (IGB). Results suggest that mean mass concentrations of eBC vary in the range between 0.46 ± 0.13 to 11.22 ± 5.09 μg m−3 with an annual mean value of ∼3.57 ± 2.39 μg m−3 during the study period. A strong temporal variation in eBC and its components i.e., eBCff (eBC from fossil fuel), and eBCbb (eBC from biomass burning) are found which shows a large variation on different temporal scales with an average value during winter (6.21 ± 3.56 μg m−3), summer (5.09 ± 3.61 μg m−3), monsoon season (1.52 ± 1.03 μg m−3), and post-monsoon (3.75 ± 2.68 μg m−3). The diurnal variation of eBC shows two different maxima between 07:00–08:00 a.m. and 08:00–10:00 p.m. An inverse relationship between eBC concentration and all meteorological parameters (temperature, wind speed, and boundary layer height) is found except relative humidity. The concentration of eBC increases with respect to RH (up to 70 %) suggesting hygroscopic growth while for higher RH (>70 %) value, eBC concentration decreases and indicates the possible wet scavenging processes in the atmosphere. Source apportionment of eBC using the “Aethalometer Model” reveals that eBCff is dominant over eBCbb in total eBC loading during the study period. Cluster analysis of HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model computed five days airmass back-trajectory suggests that airmass reached at Varanasi passes through a highly dense fire count region over the northwestern IGB and surrounding which could be the most responsible for the black carbon loading over the study region. © 2024 Turkish National Committee for Air Pollution Research and Control
Assessment of two intense dust storm characteristics over Indo – Gangetic basin and their radiative impacts: A case study
(Elsevier Ltd, 2019) Shani Tiwari; Akhilesh Kumar; Vineet Pratap; A.K. Singh
The present study is focused to examine the impacts of two intense dust storms on aerosol characteristics and their radiative impacts occurred in pre-monsoon season of 2018 (i.e. 17 May and 14 June 2018) over Kanpur (26.51° N, 80.23° E, 123 above msl). Moderate Resolution Imaging Spectroradiometer (MODIS) true colour images, trajectory pathways of dust storm along with satellite observation and AErosol RObotic NETwork (AERONET) measurements confirms that both the dust storms are either originated from or transported over the Thar Desert, causing a higher aerosol loading which spread over entire Indian-Gangetic Basin (IGB) and modifying the aerosol optical (i.e. aerosol optical depth, angstrom exponent, refractive index etc.), physical (i.e. size distribution) and radiative properties (i.e. single scattering albedo, asymmetric parameter). The space-borne Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) - retrieved aerosol measurements reveal the presence of elevated dust/polluted dust aerosol (up to 3–5 km) over IGB which is well corroborated with aerosol characteristics observed by MODIS, Ozone Monitoring Instrument (OMI) and Atmospheric Infrared Sounder (AIRS). The Dust Regional Atmospheric Model (DREAM8b) shows a good agreement with satellite retrievals with higher value of surface dust concentration in the range of 320–640 μg/m3 over Kanpur during the dust storm days. An enhancement in monthly mean outgoing longwave radiation (up to 60 Wm−2) is observed over IGB and downwind flow region during the dust storm days. The atmospheric aerosol radiative forcing is found 124 Wm−2 and 84 Wm−2 during both the dust storm days (17 May and 14 June 2018) associated with heating rate 2.69 K day−1 and 1.84 K day−1 respectively which may be significant to affect the regional atmospheric dynamics and hence the climate system also. © 2019
Atmospheric aerosols properties over Indo-Gangetic Plain: A trend analysis using ground – Truth AERONET data for the year 2009–2017
(Elsevier Ltd, 2022) Akhilesh Kumar; Vineet Pratap; Sarvan Kumar; A.K. Singh
The aerosols play an important role in the modification of the regional radiation budget. Long-term trend analysis of properties of atmospheric aerosols is important for policymakers and also for the study of the climatic implications. The Aerosol Robotic Network (AERONET) provides continuous ground-truth aerosol data during cloud-free days since two decades in India. Long-term atmospheric aerosol properties have been studied over four different sites of Indo-Gangetic Plain (IGP): Gandhi College rural background, Kanpur, urban and highly industrial area, Jaipur urban and desert dust influenced region, and Lahore urban and agriculture rich region respectively using AERONET data. The yearly variation of aerosol optical depth (AOD) along with angstrom exponent (AE), single scattering albedo (SSA), size distribution parameters (volume concentration and effective radius), and aerosol radiative forcing (ARF) have been analyzed for nine years from 2009 to 2017. A positive trend of AOD over Kanpur (0.0074/year), a negative trend over Lahore (−0.0054/year), Jaipur – 0.0027/year) and Gandhi college (−0.0008/year) was found. Volume concentration shows the increasing trend of fine mode particles which may be due to increased anthropogenic activities in comparison to natural aerosols over Kanpur, Lahore, Gandhi College, and Jaipur respectively. SSA values over Kanpur and Jaipur show dominancy of scattering while absorbing nature of particles over Lahore and Gandhi College were found. The trend of total atmospheric radiative forcing (ARFATM) over Kanpur and Jaipur locations was found to be decreased slightly but not so significantly while over Lahore and Gandhi College trend was found to increase in a significant way. The yearly trend of ARFATM over Kanpur, Lahore, Jaipur, and Gandhi College was found to be −0.76 Wm−2 /year, 2.22 Wm−2 /year, −0.08 Wm−2 /year, and 3.09 Wm−2 /year respectively. © 2022 COSPAR
Chemical characteristics of particulate matters and their emission sources over Varanasi during winter season
(Springer Science+Business Media B.V., 2020) Vineet Pratap; Akhilesh Kumar; Shani Tiwari; Pradeep Kumar; Avneesh Kumar Tripathi; Abhay Kumar Singh
The chemical composition of particulate matter impacts both human health and climate. In this study, the chemical characteristics of particulate matter was measured for four months (November 2016–February 2017) at Varanasi, which is located in the middle of the Indo-Gangetic Basin (IGB). The daily observed mean values of PM10 and PM2.5 are 134 ± 48 and 213 ± 80 μg/m3, respectively, which exceeds both national and international standards. The average value of PM2.5/PM10 ratio is 0.64 ± 0.16 which indicates a relatively higher fraction of fine particles that are attributed to anthropogenic emission sources (biomass/post-harvest burning) as corroborated by MODIS fire counts and back trajectory analysis. Ion chromatographic measurements showed that SO42−, Cl−, K+, NO3−, Na+, Ca2+, Mg2+ are the major ionic species present in the aerosol. Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM–EDX) analysis shows the prevalence of carbon-rich particles at Varanasi which is likely due to biomass burning and other anthropogenic sources. © 2020, Springer Nature B.V.
COVID-19 lockdown induced air pollution reduction over India: A lesson for future air pollution mitigation strategies
(Springer, 2021) Vineet Pratap; Shani Tiwari; Akhilesh Kumar; Abhay Kumar Singh
Air pollution is one of the biggest problems worldwide and needs to be addressed potentially with the implementation of updated stringent policies and legislative laws. The nationwide lockdown imposed to prevent the COVID-19 outbreak, has given us a unique opportunity to understand the contribution of anthropogenic emissions to the total atmospheric pollutant burden on a global as well as regional scale. Thus, in the present study, we try to investigate the impact of COVID-19 induced lockdown on common ambient air pollutants (i.e., PM2.5, NO2, and SO2) concentration over 22 cities in India using in-situ measurement under a network of Centre Pollution and Control Board (CPCB). A significant reduction in the mean mass concentration of all the studied air pollutants (i.e., PM2.5, NO2, and SO2) (nearly 10–70%) is found during different phases of lockdown which reached within the National Ambient Air Quality Standard (i.e., NAAQS). The reduction in studied air pollutants is more prominent during the first phase of lockdown (mainly NO2) which could be due to the complete shutdown of industrial activities. The outcome of the present study will be helpful for policymakers to design cost-effective and accurate air pollution mitigation strategies for the development of a sustainable environment. The study also suggests that well-planned short-term and periodical lockdown could be an alternative effective tool of air pollution mitigation. © 2021, Indian Academy of Sciences.
Dust storm characteristics over Indo-Gangetic basin through satellite remote sensing
(Elsevier, 2022) Prashant Kumar Chauhan; Akhilesh Kumar; Vineet Pratap; Shivam Kumar Chaubey; Abhay Kumar Singh
The dust storm is a common atmospheric phenomenon that modifies the optical, physical, and radiative properties of aerosols and plays a crucial role in the global radiation budget, and hence global climate change. The present chapter proposes different remote sensing techniques, such as moderate resolution imaging spectroradiometer true-color images, AErosol RObotic NETwork, cloud-aerosol LIDAR, and infrared pathfinder satellite observation (CALIPSO) to study the various properties of dust particles during dust storms over Indo-Gangetic Basin. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory model is used for the event confirmation and source identification of dust storms. © 2023 Elsevier Ltd. All rights reserved.
Effect on Aerosol Optical Depth during Diwali Festival in Varanasi, India
(Institute of Electrical and Electronics Engineers Inc., 2020) Akhilesh Kumar; Vineet Pratap; Pradeep Kumar; Abhay Kumar Singh
The present study is focused on the variation of aerosol optical depth (AOD) and chemical properties during Diwali festival over Varanasi (25.27° N, 82.99° E). AOD is taken using ground based as well as satellite based observations using MICROTOPS-II and MODIS, respectively. The elemental components are analyzed using Scanning Electron Microscope (SEM) Coupled with Energy Dispersive X-ray Microanalyzer (EDX) analysis. Analysis of particulate matters (PM2.5 and PM10) is done using high volume samplers, ground based observations. All the observations are divided in to three parts i.e. PreDiwali, Post-Diwali and Diwali event. AOD is found to be enhanced on Diwali day as huge amount of fire crackers are used by the peoples. Enhancement in AOD is observed by both ground based and satellite based observations. Enhancements in the elements are also found like carbon, silicon, sodium. However other elements like oxygen, aluminum, potassium, fluorine, zinc, chlorine were also found in the atmosphere. © 2020 Indian Radio Science Society.
Frequency distribution of aerosol optical depth over Varanasi during 2011
(Institute of Electrical and Electronics Engineers Inc., 2020) Akhilesh Kumar; Vineet Pratap; Pradeep Kumar; Abhay Kumar Singh
This work is based on the distribution of aerosol optical depth (AOD) over Varanasi site (25.270N, 82.990E). Ground based measurement is taken from MICROTOPSII sunphotometer and satellite based image data is taken from Moderate Resolution Imaging Spectroradiometer (MODIS). AOD is found to be vary mostly between 0.4 to 1.0 and Angstrom Exponent showing variation between 0.5-0.7 and 0.9-1.3, which shows mixture of course mode as well as fine mode aerosol particles over Varanasi. © 2020 Indian Radio Science Society.
Overview of solar eclipse of 21st June 2020 and its impact on solar irradiance, surface ozone and different meteorological parameters over eight cities of India
(Elsevier Ltd, 2021) Vineet Pratap; Akhilesh Kumar; Abhay Kumar Singh
The present study is aimed to investigate the variation in solar radiance, surface ozone, temperature, relative humidity and wind velocity during the most recent and one of the most significant annular solar eclipses of 21st June 2020. Effects of solar eclipse have been analyzed first time at eight different cities of India located nearly perpendicular to the eclipse axis having an eclipse magnitude from 98.6 % to 77.2 %. Significant reductions in solar irradiance at different stations were found during the maximum phase of the solar eclipse due to the occultation of the Sun by the Moon. With the progression of the solar eclipse, surface ozone concentrations were also found to be decreasing and reached to its minimum value during the maximum phase of eclipse and then after the end of the eclipse started regaining their original behavior. Overall, the change in ozone was found to be proportional to eclipse magnitude. A decrease of ozone levels ranged from 30 % to 65 % over all the stations. In addition to the above, atmospheric cooling from the solar eclipse of 21st June 2020 induced dynamical changes to the meteorological parameters (temperature, relative humidity and wind speed) with the change being most prominent during the maximum phase of the solar eclipse. © 2021 COSPAR
Performance of water vapour retrieval from MODIS and ECMWF and their validation with ground based GPS measurements over Varanasi
(Springer, 2021) Akhilesh Kumar; Sanjay Kumar; Vineet Pratap; A.K. Singh
Abstract: Water vapour is highly variable over tropical region and sensitive to weather condition, monsoon onset, green house effect, and pollution level in Ganga River. In the present study, variability in water vapour derived from Global Positioning System (GPS) over Varanasi (25°20′N, 82°59′E) during the period 2007–2010 has been studied. The GPS-derived water vapour (WV) has been compared with those retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) and ECMWF. The GPS-WV data concurrent to MODIS and ECMWF timing has been correlated to perform further analysis. To study the accuracy of water vapour retrieved from the MODIS and ECMWF, root mean square error (RMSE), absolute error (AE), correlation and standard deviation in it are computed with respect to GPS-derived water vapour. Analysis shows an annual correlation R2 = 86%, RMSE = 9.5 mm and AE (MODIS–GPS) = 7.0 mm in MODIS retrieval and annual correlation R2 = 86%, RMSE = 6.1 mm and AE (ECMWF–GPS) = 2.4 mm in ECMWF reanalysis retrieval. Correlation of ECMWF and MODIS datasets with the GPS datasets are found to vary significantly with seasons. The correlation is high during monsoon season and low during spring season. Water vapour is found to be an indicator for the onset of monsoon. Research Highlights: Accuracy of water vapor (WV) retrieved from the MODIS and ECMWF with respect to GPS WV.High Annual correlation of R2 = 0.86 between both MODIS–GPS and ECMWF–GPS.The correlation is high during monsoon season and low during spring season.The performance of ECMWF is found to be better than that of MODIS. © 2021, Indian Academy of Sciences.
Pre-monsoon Study of Aerosol Parameters and Particulate Matters over Varanasi for 2017
(Institute of Electrical and Electronics Engineers Inc., 2020) Vineet Pratap; Akhilesh Kumar; Pradeep Kumar; Abhay Kumar Singh
Aerosol characteristics over Varanasi region during pre-monsoon (April-June) period were analyzed for year 2017. Aerosol optical properties and angstrom exponent were measured using MICROTOPS-II Sunphotometer. The mean AOD for the period of study was found to be 0.78 where as mean angstrom exponent (AE at 440-870 nm) was found to be 0.29. Average concentrations of PM2.5 and PM10 were found to be 38.15 ± 22.48 μg/m3 and 126.10 ± 45.39 μg/m3 respectively, which clearly demonstrates dominance of coarse mode particles particularly in this season. © 2020 Indian Radio Science Society.
Seasonal characteristics of PM1, PM2.5, and PM10 over Varanasi during 2019–2020
(Frontiers Media S.A., 2022) Prashant Kumar Chauhan; Akhilesh Kumar; Vineet Pratap; Abhay Kumar Singh
Particulate matter (PM) concentrations and aerosol optical depth (AOD) are measured and correlated simultaneously using a high-volume sampler and a MICROTOPS-II Sunphotometer, respectively. The present work deals with the characteristics of particulate matter (PM1, PM2.5, and PM10) over Varanasi, from April 2019 to March 2020. Daily variation, as well as seasonal variation, reveals the dominancy of fine-mode particles over the Varanasi region in the winter season and the dominancy of coarse-mode particles in the summer season, which was further confirmed by calculating the ratio between particulate matter (PM1/PM10 and PM2.5/PM10). This ratio was discovered to be lowest in the summer and highest in the winter. Annual mean concentrations of PM1, PM2.5, and PM10 are found to be 93.91, 111.34, and 180.70 μgm−3, respectively. The seasonal variation shows relatively a higher concentration of PM1, PM2.5, and PM10 in the winter season, which may be due to stable meteorological conditions and increased biomass burning in winter. Diurnal and seasonal variations in AOD were also studied during this period. A large and small value of AOD represents the dominancy of fine particles over coarse particles. At 500 nm, maximum (1.17) and minimum (0.44) AODs were measured in December and August of 2019, respectively. There was a statistically significant correlation between PM particles (PM1, PM2.5, and PM10) and AOD. Elemental analysis shows that fluorine and carbon are the major elements that were observed in selected samples during the post-monsoon and winter season using SEM-EDX analysis. Copyright © 2022 Chauhan, Kumar, Pratap and Singh.
Seasonal Variability of Atmospheric Aerosols over Varanasi Region during 2010-2016
(Institute of Electrical and Electronics Engineers Inc., 2020) Vineet Pratap; Akhilesh Kumar; Pradeep Kumar; Abhay Kumar Singh
The role of atmospheric aerosols in climate and climate change is one of the largest uncertainties in understanding the present climate and in capability to predict future climate change. Due to which, the study of optical properties of atmospheric aerosols were conducted for seven years to see the massive aerosol loading and its seasonal variability using satellite data obtained from MODIS. In the present study AOD was analyzed for the year 2010-2016 using satellite data obtained from MODIS Terra for different seasons. The mean AOD for Winter, Pre-monsoon, Monsoon and Post-monsoon were found to be 0.73, 0.46, 0.37, and 0.72 respectively. Highest value of AOD was found during winter season and lowest during Monsoon season. Similarly respective mean angstrom coefficient for winter, Pre-monsoon, Monsoon and Post-monsoon were found to be 1.48, 0.71, 1.28, and 1.36. © 2020 Indian Radio Science Society.
Variability in air pollutants and AOD over Varanasi region for years 2005-2010
(Institute of Electrical and Electronics Engineers Inc., 2019) Vineet Pratap; Akhilesh Kumar; A.K. Singh
This study is carried out in order to examine long term (2005-2016) trends of different air pollutants viz. (AOD, BC, SO2, NO2, CO and dust) over Varanasi, India. Varanasi (25.3o N, 83.0o E, 83 m amsl), located in the west bank of the Ganges river in the central Indo-Gangetic Plain region. Varanasi has a population of around 1.5 million, with very high traffic density and anthropogenic pollution, while the surrounding regions are very fertile for growing rice, wheat and major cereal crop production. © 2019 URSI. All rights reserved.
Variation of aerosol optical and physical properties and their impact on rainfall over Indo-Gangetic Basin
(Springer, 2025) Akhilesh Kumar; Sadanand N. Singh; Prashant Kumar Chauhan; Gyaneshwar R. Sharma; Vineet Pratap; Anil Kumar Singh
Aerosols are one of the important constituents of the atmosphere which can disturb the Indian monsoon by affecting the precipitation over Indian subcontinents. To investigate the consequence of aerosol properties on rainfall, we have analysed the long-term annual trends and annual correlation between aerosol properties and rainfall using ground-based AErosol RObotic NETwork (AERONET) data and satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) data. We have used four diverse sites in Indo- Gangetic Basin (IGB); Gandhi College, Jaipur, Lahore, and Kanpur. A significant trend of aerosol optical depth (AOD) and angstrom exponent (AE) along with the trend of imaginary refractive index (IRI)/ real refractive index (RRI) followed by the trend of single scattering albedo (SSA) over Gandhi College, Jaipur and Lahore suggests enhancement of coarse mode scattering and absorbing aerosols. In contrast, over Lahore, a significant reduction in fine mode absorbing aerosols is found. The trend of Aerosol Radiative Forcing (ARF) is found to be decreasing over Gandhi College, Lahore, and Kanpur while it is found to be increasing over Jaipur. A significantly increasing trend of rainfall over Lahore and Kanpur while a considerably decreasing trend over Gandhi College and Jaipur is, found. AOD shows a positive correlation over all locations and AE also indicates a positive correlation over three locations instead of Jaipur. SSA exhibits a negative correlation with rainfall over Jaipur, Kanpur, and Gandhi College while it is found to have a positive correlation over Lahore. RRI shows a negative trend overall locations except Kanpur. In contrast, IRI shows a negative trend with rainfall over all of Lahore and Kanpur and a positive trend over Jaipur and Gandhi College. And, ARF displays a constructive correlation with rainfall over all the locations. © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025.
Variation of aerosol parameters (AI, AOD) and SO2 over Indo-Gangetic basin during COVID-19 outbreaks
(Springer, 2024) Akhilesh Kumar; Vineet Pratap; S.N. Singh; A.K. Singh
To stop the spread of COVID-19 infections, idea of complete and partial lockdowns was implemented in several countries. In the present work, variation of aerosol index (AI), aerosol optical depth (AOD) and SO2 concentration over Indo-Gangetic Basin regions (over highly polluted cities: Varanasi, Kanpur and Delhi) were analyzed to see the impact of lockdown periods during 2020. AI data were taken from satellite based ozone monitoring instrument while AOD and SO2 data were taken from moderate resolution spectroradiometer (MODIS). Lockdown periods of March, April, May and June months of 2020 were compared with the same months of 2017, 2018 and 2019. Significantly large difference in AI was observed associated with decreased value of AI during lockdown periods followed by AOD values and SO2 concentrations. All these cities of Northern India (Varanasi, Kanpur and Delhi) show significant decline in aerosol index which indicate less emissions of black carbon and other absorbing aerosol particles into the atmosphere. Trend of AI and SO2 concentration were found to be negative due to the sudden decrease in their values. Decline in the aerosol parameters (AI and AOD) and air pollutant (SO2) suggest improved air quality of the highly polluted cities of India. © 2023, Indian Association for the Cultivation of Science.
Wintertime variation of PM10, PM2.5, Black Carbon, and Aerosol Optical Depth over Varanasi
(Institute of Electrical and Electronics Engineers Inc., 2022) Prashant K. Chauhan; Akhilesh Kumar; Vineet Pratap; Satyam Prajapati; Abhay K. Singh
Black Carbon (BC) and Particulate Matter (PM10 and PM2.5) are measured over Varanasi during the winter season. They are the most crucial atmospheric aerosols that play an important role in Earth's radiation budget by absorbing solar and terrestrial radiation. Aerosol Optical Depth (AOD) is the measure of extinction of incoming solar radiation by air particles distributed in a vertical column of the atmosphere. The influence of the atmospheric boundary layer (ABL) is observed on the diurnal variation of BC, PM10, and PM2.5. The concentration of these parameters was high during morning and evening hours when ABL is lying near the ground. Maximum and minimum concentrations of PM10 and PM2.5 are found to be in November and February. Burning firecrackers during Diwali in November could be the reason for high aerosol loading. Higher BC concentration is measured in January due to increased anthropogenic activities and biomass burning. AOD at 500 nm is found to be higher in December and lower in February. The higher value of AOD at a shorter wavelength suggests the dominance of fine mode particles. © 2022 International Radio Science Union (URSI).