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| Titel |
Modeling upper tropospheric and lower stratospheric water vapor anomalies |
| VerfasserIn |
M. R. Schoeberl, A. E. Dessler, T. Wang |
| 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 ; 13, no. 15 ; Nr. 13, no. 15 (2013-08-13), S.7783-7793 |
| Datensatznummer |
250085623
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| Publikation (Nr.) |
 copernicus.org/acp-13-7783-2013.pdf |
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| Zusammenfassung |
| The domain-filling, forward trajectory calculation model developed by
Schoeberl and Dessler (2011) is used to further investigate processes that
produce upper tropospheric and lower stratospheric water vapor anomalies. We
examine the pathways parcels take from the base of the tropical tropopause
layer (TTL) to the lower stratosphere. Most parcels found in the lower
stratosphere arise from East Asia, the Tropical West Pacific (TWP) and
Central/South America. The belt of TTL parcel origins is very wide compared
to the final dehydration zones near the top of the TTL. This is due to the
convergence of rising air due to the stronger diabatic heating near the
tropopause relative to levels above and below. The observed water vapor
anomalies – both wet and dry – correspond to regions where parcels have
minimal displacement from their initialization. These minimum displacement
regions include the winter TWP and the Asian and American monsoons. To
better understand the stratospheric water vapor concentration we introduce
the water vapor spectrum and investigate the source of the wettest and
driest components of the spectrum. We find that the driest air parcels
originate below the TWP, moving upward to dehydrate in the TWP cold upper
troposphere. The wettest air parcels originate at the edges of the TWP as
well as in the summer American and Asian monsoons. The wet air parcels are
important since they skew the mean stratospheric water vapor distribution
toward higher values. Both TWP cold temperatures that produce dry parcels as
well as extra-TWP processes that control the wet parcels determine
stratospheric water vapor. |
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