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.