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| Titel |
Simulation of the isotopic composition of stratospheric water vapour – Part 2: Investigation of HDO / H2O variations |
| VerfasserIn |
R. Eichinger, P. Jöckel, S. Lossow |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2015-06-29), S.7003-7015 |
| Datensatznummer |
250119856
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| Publikation (Nr.) |
 copernicus.org/acp-15-7003-2015.pdf |
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| Zusammenfassung |
| Studying the isotopic composition of water vapour in the lower stratosphere
can reveal the driving mechanisms of changes in the stratospheric
water vapour budget and therefore help to explain the trends and variations
of stratospheric water vapour during recent decades.
We equipped a global chemistry climate model with a description of the water isotopologue
HDO, comprising its physical and chemical fractionation effects throughout
the hydrological cycle.
We use this model to improve our understanding of the processes
which determine the patterns in the stratospheric water isotope composition and
in the water vapour budget itself.
The link between the water vapour budget and its isotopic composition in the tropical stratosphere
is presented through their correlation in a simulated 21-year time series.
The two quantities depend on the same processes; however, they are influenced
with different strengths.
A sensitivity experiment shows that fractionation effects during the oxidation of methane have a damping effect on
the stratospheric tape recorder signal in the water isotope ratio.
Moreover, the chemically produced high water isotope ratios
overshadow the tape recorder in the upper stratosphere.
Investigating the origin of the boreal-summer signal of isotopically enriched water vapour
reveals that in-mixing of old stratospheric air from the extratropics and the intrusion of
tropospheric water vapour into the stratosphere complement each other
in order to create the stratospheric isotope ratio tape recorder signal.
For this, the effect of ice lofting in monsoon systems is shown to play a crucial role.
Furthermore, we describe a possible pathway of isotopically enriched water vapour through the
tropopause into the tropical stratosphere. |
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