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| Titel |
A tropical West Pacific OH minimum and implications for stratospheric composition |
| VerfasserIn |
M. Rex, I. Wohltmann, T. Ridder, R. Lehmann, K. Rosenlof, P. Wennberg, D. Weisenstein, J. Notholt, K. Krüger, V. Mohr, S. Tegtmeier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 9 ; Nr. 14, no. 9 (2014-05-15), S.4827-4841 |
| Datensatznummer |
250118703
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| Publikation (Nr.) |
 copernicus.org/acp-14-4827-2014.pdf |
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| Zusammenfassung |
| Most of the short-lived biogenic and anthropogenic chemical species that are
emitted into the atmosphere break down efficiently by reaction with OH and do
not reach the stratosphere. Here we show the existence of a pronounced
minimum in the tropospheric column of ozone over the West Pacific, the main
source region for stratospheric air, and suggest a corresponding minimum of
the tropospheric column of OH. This has the potential to amplify the impact
of surface emissions on the stratospheric composition compared to the impact
when assuming globally uniform OH conditions. Specifically, the role of
emissions of biogenic halogenated species for the stratospheric halogen
budget and the role of increasing emissions of SO2 in Southeast Asia or
from minor volcanic eruptions for the increasing stratospheric aerosol
loading need to be reassessed in light of these findings. This is also
important since climate change will further modify OH abundances and
emissions of halogenated species. Our study is based on ozone sonde
measurements carried out during the TransBrom cruise with the RV
Sonne roughly along 140–150° E in October 2009 and corroborating ozone and
OH measurements from satellites, aircraft campaigns and FTIR instruments.
Model calculations with the GEOS-Chem Chemistry and Transport Model (CTM) and
the ATLAS CTM are used to simulate the tropospheric OH distribution over the
West Pacific and the transport pathways to the stratosphere. The potential
effect of the OH minimum on species transported into the stratosphere is
shown via modeling the transport and chemistry of CH2Br2 and SO2. |
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