Comparison of inorganic chlorine in the Southern hemispheric lowermost stratosphere during late winter 2019
- Stratospheric inorganic chlorine (Cly) is predominantly released from long-lived chlorinated source gases and, to a small extent, very short-lived chlorinated substances. Cly includes the reservoir species (HCl and ClONO2) and active chlorine species (i.e., ClOx). The active chlorine species drive catalytic cycles that deplete ozone in the polar winter stratosphere. This work presents calculations of inorganic chlorine (Cly) derived from chlorinated source gas measurements on board the High Altitude and Long Range Research Aircraft (HALO) during the Southern Hemisphere Transport, Dynamic and Chemistry (SouthTRAC) campaign in austral late winter and early spring 2019. Results are compared to Cly in the Northern Hemisphere derived from measurements of the POLSTRACC-GW-LCYCLE-SALSA (PGS) campaign in the Arctic winter of 2015/2016. A scaled correlation was used for PGS data, since not all source gases were measured. Using the SouthTRAC data, Cly from a scaled correlation was compared to directly determined Cly and agreed well. An air mass classification based on in situ N2O measurements allocates the measurements to the vortex, the vortex boundary region, and midlatitudes. Although the Antarctic vortex was weakened in 2019 compared to previous years, Cly reached 1687±19 ppt at 385 K; therefore, up to around 50 % of total chlorine was found in inorganic form inside the Antarctic vortex, whereas only 15 % of total chlorine was found in inorganic form in the southern midlatitudes. In contrast, only 40 % of total chlorine was found in inorganic form in the Arctic vortex during PGS, and roughly 20 % was found in inorganic form in the northern midlatitudes. Differences inside the two vortices reach as much as 540 ppt, with more Cly in the Antarctic vortex in 2019 than in the Arctic vortex in 2016 (at comparable distance to the local tropopause). To our knowledge, this is the first comparison of inorganic chlorine within the Antarctic and Arctic polar vortices. Based on the results of these two campaigns, the differences in Cly inside the two vortices are substantial and larger than the inter-annual variations previously reported for the Antarctic.
Author: | Markus JessweinORCiDGND, Heiko BozemORCiDGND, Hans-Christoph LachnittGND, Peter HoorORCiDGND, Thomas WagenhäuserORCiD, Timo Keber, Tanja J. SchuckORCiDGND, Andreas EngelORCiD |
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URN: | urn:nbn:de:hebis:30:3-822676 |
DOI: | https://doi.org/10.5194/acp-2021-356 |
ISSN: | 1680-7375 |
Parent Title (English): | Atmospheric chemistry and physics. Discussions |
Publisher: | EGU |
Place of publication: | Katlenburg-Lindau |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2021/05/28 |
Date of first Publication: | 2021/05/28 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/02/19 |
Volume: | 21 |
Page Number: | 27 |
First Page: | 1 |
Last Page: | 27 |
Note: | Data availability. The observational data of the HALO flights during the SouthTRAC campaign are available via the HALO database https://halo-db.pa.op.dlr.de (last access: XY). |
Note: | This work was done at the University of Frankfurt. Funding from BMBF Programme ROMIC-II under Grant nr. 01LG1908B (SCI-HI) and from the German science foundation (DFG) under grant numbers EN367/13-1, EN367/14-1 and EN367/16-1 and EN367/17-1 for the PGS and SouthTRAC campaigns. |
Note: | Begutachteter Artikel erschienen in: Atmospheric chemistry and physics, 21.2021, Nr. 23, S. 17225-17241, doi: 10.5194/acp-21-17225-2021 |
HeBIS-PPN: | 522182860 |
Institutes: | Geowissenschaften / Geographie |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften | |
5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften | |
Sammlungen: | Universitätspublikationen |