Did the COVID-19 Crisis Reduce Free Tropospheric Ozone across the Northern Hemisphere? | CU Experts

Throughout spring and summer 2020, ozone stations in the northern; extratropics recorded unusually low ozone in the free troposphere. From; April to August, and from 1 to 8 kilometers altitude, ozone was on; average 7% (~4 ppbv) below the 2000 to 2020; climatological mean. Such low ozone, over several months, and at so many; stations, has not been observed in any previous year since at least; 2000. Atmospheric composition re-analyses from the Copernicus Atmosphere; Monitoring Service and simulations from the NASA GMI model indicate that; the large 2020 springtime ozone depletion in the Arctic stratosphere has; contributed less than one quarter to the observed tropospheric anomaly.; The observed anomaly is consistent with two recent model simulations,; which assume emission reductions similar to those caused by the COVID-19; crisis. COVID-19 related emission reductions appear to be the major; cause for the observed low free tropospheric ozone in 2020.

Steinbrecht W; Kubistin D; Plass-Dulmer C; Tarasick DW; Davies J; Gathen PVD; Deckelmann H; Jepsen N; Kivi R; Lyall N

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