Satellite Observations of AOD in 4 Northern Hemisphere Source Regions during the COVID-19 Pandemic

Abstract

Anticipated future reductions in aerosol emissions are expected to accelerate warming and substantially change precipitation characteristics. It is therefore vital to identify existing patterns and possible future pathways of anthropogenic aerosol reductions. The COVID-19 pandemic prompted abrupt, global declines in transportation and industrial activities, providing opportunities to study the aerosol effects of pandemic-driven emissions changes. Here, measures of aerosol optical depth (AOD) from two satellite instruments are used to characterize aerosol burdens in 2020 in four Northern Hemisphere source regions (East & Central China, the United States, India, and Europe). In most regions, spring and summer AOD was substantially lower than in previous years. However, in India and East & Central China, the COVID-19 AOD signature was eclipsed by sources of natural variability (dust) and a multi-year trend, respectively, suggesting that COVID-19-related emissions reductions account for substantially less of the 2020 anomalies in these regions than might otherwise be assumed.