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Titel |
Vertical transport rates and concentrations of OH and Cl radicals in the Tropical Tropopause Layer from observations of CO2 and halocarbons: implications for distributions of long- and short-lived chemical species |
VerfasserIn |
S. Park, E. L. Atlas, R. Jiménez, B. C. Daube, E. W. Gottlieb, J. Nan, D. B. A. Jones, L. Pfister, T. J. Conway, T. P. Bui, R.-S. Gao, S. C. Wofsy |
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 ; 10, no. 14 ; Nr. 10, no. 14 (2010-07-21), S.6669-6684 |
Datensatznummer |
250008645
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Publikation (Nr.) |
copernicus.org/acp-10-6669-2010.pdf |
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Zusammenfassung |
Rates for large-scale vertical transport of air in the
Tropical Tropopause Layer (TTL) were determined using high-resolution, in situ
observations of CO2 concentrations in the tropical upper troposphere
and lower stratosphere during the NASA Tropical Composition, Cloud and
Climate Coupling (TC4) campaign in August 2007. Upward movement of trace
gases in the deep tropics was notably slower in TC4 than during the Costa
Rica AURA Validation Experiment (CR-AVE), in January 2006. Transport rates
in the TTL were combined with in situ measurements of chlorinated and
brominated organic compounds from whole air samples to determine chemical
loss rates for reactive chemical species, providing empirical vertical
profiles for 24-h mean concentrations of hydroxyl radicals (OH) and
chlorine atoms in the TTL. The analysis shows that important short-lived
species such as CHCl3, CH2Cl2, and CH2Br2 have
longer chemical lifetimes than the time for transit of the TTL, implying
that these species, which are not included in most models, could readily
reach the stratosphere and make significant contributions of chlorine and/or
bromine to stratospheric loading. |
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