Impact of COVID-19 lockdown on aerosol optical and radiative properties over Indo-Gangetic Plain

Abstract

Aerosol optical and radiative properties, measured with the ground based sun-sky radiometer (under AERONET), were explored at Kanpur in the central and Gandhi College (Ballia) in the Eastern Indo-Gangetic Plain (IGP) in Northern India during January to July 2019 (non-lockdown) and 2020 (lockdown). This year 2020 is marked an overall reduction of 15.79% and 3.39% in aerosol optical depth (AOD) than year 2019 at Kanpur and Gandhi College respectively. Lockdown 1 (23rd March to 14th April 2020) showed a reduction of 52.52% and 42.22% in AOD compared to pre-lockdown condition at Kanpur and Gandhi College respectively. Higher values of angstrom exponent measured at Eastern region (1.13 ± 0.17) than central region (0.97 ± 0.26) indicating the dominance of fine particles at Gandhi College. There was an overall reduction of 1.31% in single scattering albedo (SSA) at Kanpur while 4.34% reduction was observed at Gandhi College in year 2020 than 2019. The resultant atmospheric forcing and heating rate shows 11.86% reduction at Kanpur while 35.27% increase at Gandhi College during the lockdown period in 2020 compared to 2019. However, these values were found to decrease by 23.48% and 15.07% at Kanpur and Gandhi College respectively during the strict lockdown period compared to year 2019.