Authors:	Tomsche, Laura Marsing, Andreas Jurkat-Witschas, Tina Lucke, Johannes Kaufmann, Stefan Kaiser, Katharina Schneider, Johannes Scheibe, Monika Schlager, Hans Röder, Lenard Fischer, Horst Obersteiner, Florian Zahn, Andreas Zöger, Martin Lelieveld, Jos Voigt, Christiane
Title:	Enhanced sulfur in the upper troposphere and lower stratosphere in spring 2020
Online publication date:	13-Apr-2023
Year of first publication:	2022
Language:	english
Abstract:	Sulfur compounds in the upper troposphere and lower stratosphere (UTLS) impact the atmosphere radiation budget, either directly as particles or indirectly as precursor gas for new particle formation. In situ measurements in the UTLS are rare but are important to better understand the impact of the sulfur budget on climate. The BLUESKY mission in May and June 2020 explored an unprecedented situation. (1) The UTLS experienced extraordinary dry conditions in spring 2020 over Europe, in comparison to previous years, and (2) the first lockdown of the COVID-19 pandemic caused major emission reductions from industry, ground, and airborne transportation. With the two research aircraft HALO and Falcon, 20 flights were conducted over central Europe and the North Atlantic to investigate the atmospheric composition with respect to trace gases, aerosol, and clouds. Here, we focus on measurements of sulfur dioxide (SO2) and particulate sulfate (SO2􀀀4 ) in the altitude range of 8 to 14.5 km which show unexpectedly enhanced mixing ratios of SO2 in the upper troposphere and of SO2􀀀4 in the lowermost stratosphere. In the UT, we find SO2 mixing ratios of (0:07 0:01) ppb, caused by the remaining air traffic, and reduced SO2 sinks due to low OH and low cloud fractions and to a minor extent by uplift from boundary layer sources. Particulate sulfate showed elevated mixing ratios of up to 0.33 ppb in the LS. We suggest that the eruption of the volcano Raikoke in June 2019, which emitted about 1 Tg SO2 into the stratosphere in northern idlatitudes, caused these enhancements, in addition to Siberian and Canadian wildfires and other minor volcanic eruptions. Our measurements can help to test models and lead to new insights in the distribution of sulfur compounds in the UTLS, their sources, and sinks. Moreover, these results can contribute to improving simulations of the radiation budget in the UTLS with respect to sulfur effects.
DDC:	540 Chemie 540 Chemistry and allied sciences 550 Geowissenschaften 550 Earth sciences 624 Ingenieurbau und Umwelttechnik 624 Civil engineering 660 Technische Chemie 660 Chemical engineering
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8835
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Atmospheric Chemistry and Physics 22
Pages or article number:	15135 15151
Publisher:	Copernicus GmbH EGU
Publisher place:	Katlenburg-Lindau
Issue date:	2022
ISSN:	1680-7375
Publisher DOI:	10.5194/acp-22-15135-2022
Appears in collections:	DFG-491381577-G