Reduction of surface radiative forcing observed from remote sensing data during global COVID-19 lockdown

Usman Mazhar; Shuanggen Jin; Muhammad Bilal; Md Arfan Ali; Rehana Khan

doi:10.1016/j.atmosres.2021.105729

Reduction of surface radiative forcing observed from remote sensing data during global COVID-19 lockdown

Atmos Res. 2021 Oct 15:261:105729. doi: 10.1016/j.atmosres.2021.105729. Epub 2021 Jun 11.

Authors

Usman Mazhar¹, Shuanggen Jin^{1

2}, Muhammad Bilal³, Md Arfan Ali³, Rehana Khan⁴

Affiliations

¹ School of Remote Sensing and Geomatics Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
² Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China.
³ Lab of Environmental Remote sensing, School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China.
⁴ Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Key Laboratory of Meteorological Disaster, Ministry of Education, International Joint Laboratory on Climate and Environment Change, Key laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing 210044, China.

Abstract

The calamity of the COVID-19 pandemic during the early half of 2020 not only caused a huge physical and economic loss but altered the social behavior of the whole world. The social and economic stagnation imposed in many countries and served as a major cause of perturbation in atmospheric composition. This paper utilized the relation between atmospheric composition and surface radiation and analyzed the impact of global COVID-19 lockdown on land surface solar and thermal radiation. Top of atmosphere (TOA) and surface radiation are obtained from the Clouds and Earth's Radiant Energy System (CERES) and European Reanalysis product (ERA5) reanalysis product. Aerosol Optical Depth (AOD) is obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) while Nitrogen dioxide (NO₂)_, and sulfur dioxide (SO₂) are obtained from Ozone Monitoring Instrument (OMI). Observations of all mentioned parameters are studied for the global lockdown period of 2020 (from January to July) and compared with the corresponding months of the previous four years (2016-19) observations. Regarding surface radiation, April 2020 is the most affected month during the pandemic in which 0.2% increased net solar radiation (NSR), while 3.45% and 4.8% decreased net thermal radiation (NTR) and net radiation (NR) respectively was observed. Average radiative forcing during March-May 2020 was observed as 1.09 Wm^-2, -2.19 Wm^-2 and -1.09 Wm^-2 for NSR, NTR and NR, respectively. AOD was reduced by 0.2% in May 2020 while NO₂ and SO₂ were reduced by 5.4% and 8.8%, respectively, in April 2020. It was observed that NO₂ kept on reducing since January 2020 while SO₂ kept on reducing since February 2020 which were the pre-lockdown months. These results suggest that a more sophisticated analysis is needed to explain the atmosphere-radiation relation.

Keywords: Air pollution; COVID-19; Economic and social lockdown; Land surface radiation.