TY  - JOUR
A1  - Steinbrecht, Wolfgang
A1  - Kubistin, Dagmar
A1  - Plass‐Dülmer, Christian
A1  - Davies, Jonathan
A1  - Tarasick, David W.
A1  - Gathen, Peter von der
A1  - Deckelmann, Holger
A1  - Jepsen, Nis
A1  - Kivi, Rigel
A1  - Lyall, Norrie
A1  - Palm, Matthias
A1  - Notholt, Justus
A1  - Kois, Bogumil
A1  - Oelsner, Peter
A1  - Allaart, Marc
A1  - Piters, Ankie
A1  - Gill, Michael
A1  - Van Malderen, Roeland
A1  - Delcloo, Andy W.
A1  - Sussmann, Ralf
A1  - Mahieu, Emmanuel
A1  - Servais, Christian
A1  - Romanens, Gonzague
A1  - Stübi, Rene
A1  - Ancellet, Gerard
A1  - Godin‐Beekmann, Sophie
A1  - Yamanouchi, Shoma
A1  - Strong, Kimberly
A1  - Johnson, Bryan
A1  - Cullis, Patrick
A1  - Petropavlovskikh, Irina
A1  - Hannigan, James W.
A1  - Hernandez, Jose‐Luis
A1  - Diaz Rodriguez, Ana
A1  - Nakano, Tatsumi
A1  - Chouza, Fernando
A1  - Leblanc, Thierry
A1  - Torres, Carlos
A1  - Garcia, Omaira
A1  - Röhling, Amelie N.
A1  - Schneider, Matthias
A1  - Blumenstock, Thomas
A1  - Tully, Matt
A1  - Paton‐Walsh, Clare
A1  - Jones, Nicholas
A1  - Querel, Richard
A1  - Strahan, Susan
A1  - Stauffer, Ryan M.
A1  - Thompson, Anne M.
A1  - Inness, Antje
A1  - Engelen, Richard
A1  - Chang, Kai‐Lan
A1  - Cooper, Owen R.
T1  - COVID‐19 Crisis Reduces Free Tropospheric Ozone Across the Northern Hemisphere
Y1  - 2021-02-26
VL  - 48
IS  - 5
JF  - Geophysical Research Letters
DO  - 10.23689/fidgeo-4331
N2  - 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 nmol/mol) below the 2000–2020 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 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 contributed less than one‐quarter of the observed tropospheric anomaly. The observed anomaly is consistent with recent chemistry‐climate model simulations, which assume emissions reductions similar to those caused by the COVID‐19 crisis. COVID‐19 related emissions reductions appear to be the major cause for the observed reduced free tropospheric ozone in 2020.
N2  - Plain Language Summary: Worldwide actions to contain the COVID‐19 virus have closed factories, grounded airplanes, and have generally reduced travel and transportation. Less fuel was burnt, and less exhaust was emitted into the atmosphere. Due to these measures, the concentration of nitrogen oxides and volatile organic compounds (VOCs) decreased in the atmosphere. These substances are important for photochemical production and destruction of ozone in the atmosphere. In clean or mildly polluted air, reducing nitrogen oxides and/or VOCs will reduce the photochemical production of ozone and result in less ozone. In heavily polluted air, in contrast, reducing nitrogen oxides can increase ozone concentrations, because less nitrogen oxide is available to destroy ozone. In this study, we use data from three types of ozone instruments, but mostly from ozonesondes on weather balloons. The sondes fly from the ground up to 30 kilometers altitude. In the first 8 km, we find significantly reduced ozone concentrations in the northern extratropics during spring and summer of 2020, less than in any other year since at least 2000. We suggest that reduced emissions due to the COVID‐19 crisis have lowered photochemical ozone production and have caused the observed ozone reductions in the troposphere.
N2  - Key Points: In spring and summer 2020, stations in the northern extratropics report on average 7% (4 nmol/mol) less tropospheric ozone than normal Such low tropospheric ozone, over several months, and at so many sites, has not been observed in any previous year since at least 2000 Most of the reduction in tropospheric ozone in 2020 is likely due to emissions reductions related to the COVID‐19 pandemic
UR  - http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/8677
ER  -