TY  - JOUR
AU  - Voigt, Christiane
AU  - Lelieveld, Jos
AU  - Schlager, Hans
AU  - Schneider, Johannes
AU  - Curtius, Joachim
AU  - Meerkötter, Ralf
AU  - Sauer, Daniel
AU  - Bugliaro, Luca
AU  - Bohn, Birger
AU  - Crowley, John N.
AU  - Erbertseder, Thilo
AU  - Groß, Silke
AU  - Hahn, Valerian
AU  - Li, Qiang
AU  - Mertens, Mariano
AU  - Pöhlker, Mira L.
AU  - Pozzer, Andrea
AU  - Schumann, Ulrich
AU  - Tomsche, Laura
AU  - Williams, Jonathan
AU  - Zahn, Andreas
AU  - Andreae, Meinrat
AU  - Borrmann, Stephan
AU  - Bräuer, Tiziana
AU  - Dörich, Raphael
AU  - Dörnbrack, Andreas
AU  - Edtbauer, Achim
AU  - Ernle, Lisa
AU  - Fischer, Horst
AU  - Giez, Andreas
AU  - Granzin, Manuel
AU  - Grewe, Volker
AU  - Harder, Hartwig
AU  - Heinritzi, Martin
AU  - Holanda, Bruna A.
AU  - Jöckel, Patrick
AU  - Kaiser, Katharina
AU  - Krüger, Ovid O.
AU  - Lucke, Johannes
AU  - Marsing, Andreas
AU  - Martin, Anna
AU  - Matthes, Sigrun
AU  - Pöhlker, Christopher
AU  - Pöschl, Ulrich
AU  - Reifenberg, Simon
AU  - Ringsdorf, Akima
AU  - Scheibe, Monika
AU  - Tadic, Ivan
AU  - Zauner-Wieczorek, Marcel
AU  - Henke, Rolf
AU  - Rapp, Markus
TI  - Cleaner Skies during the COVID-19 Lockdown
JO  - Bulletin of the American Meteorological Society
VL  - 103
IS  - 8
SN  - 0003-0007
CY  - Boston, Mass.
PB  - ASM
M1  - FZJ-2022-05516
SP  - E1796 - E1827
PY  - 2022
AB  - During spring 2020, the COVID-19 pandemic caused massive reductions in emissions from industry and ground and airborne transportation. To explore the resulting atmospheric composition changes, we conducted the BLUESKY campaign with two research aircraft and measured trace gases, aerosols, and cloud properties from the boundary layer to the lower stratosphere. From 16 May to 9 June 2020, we performed 20 flights in the early COVID-19 lockdown phase over Europe and the Atlantic Ocean. We found up to 50% reductions in boundary layer nitrogen dioxide concentrations in urban areas from GOME-2B satellite data, along with carbon monoxide reductions in the pollution hot spots. We measured 20%–70% reductions in total reactive nitrogen, carbon monoxide, and fine mode aerosol concentration in profiles over German cities compared to a 10-yr dataset from passenger aircraft. The total aerosol mass was significantly reduced below 5 km altitude, and the organic aerosol fraction also aloft, indicative of decreased organic precursor gas emissions. The reduced aerosol optical thickness caused a perceptible shift in sky color toward the blue part of the spectrum (hence BLUESKY) and increased shortwave radiation at the surface. We find that the 80% decline in air traffic led to substantial reductions in nitrogen oxides at cruise altitudes, in contrail cover, and in resulting radiative forcing. The light extinction and depolarization by cirrus were also reduced in regions with substantially decreased air traffic. General circulation–chemistry model simulations indicate good agreement with the measurements when applying a reduced emission scenario. The comprehensive BLUESKY dataset documents the major impact of anthropogenic emissions on the atmospheric composition.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000886646700005
DO  - DOI:10.1175/BAMS-D-21-0012.1
UR  - https://juser.fz-juelich.de/record/912324
ER  -