ATMOS stratospheric deuterated water and implications for troposphere-stratosphere transport
Abstract
Measurements of the isotopic composition of stratospheric water by the ATMOS instrument are used to infer the convective history of stratospheric air. The average water vapor entering the stratosphere is found to be highly depleted of deuterium, with δD_w of −670±80 (67% deuterium loss). Model calculations predict, however, that under conditions of thermodynamic equilibrium, dehydration to stratospheric mixing ratios should produce stronger depletion to δD_w of −800 to −900 (80–90% deuterium loss). Deuterium enrichment of water vapor in ascending parcels can occur only in conditions of rapid convection; enrichments persisting into the stratosphere require that those conditions continue to near-tropopause altitudes. We conclude that either the predominant source of water vapor to the uppermost troposphere is enriched convective water, most likely evaporated cloud ice, or troposphere-stratosphere transport occurs closely associated with tropical deep convection.
Additional Information
© 1996 American Geophysical Union. Received November 3, 1995; revised January 23, 1996; accepted April 4, 1996. We thank Michael Brown for his comments and suggestions on this manuscript, and David Keith and Nilton Renno for useful discussions. EJM acknowledges the support of a National Science Foundation Graduate Fellowship and a NASA Global Change Graduate Fellowship. This research was supported in part by NASA grant NAGW-413 to the California Institute of Technology.Attached Files
Published - grl9357.pdf
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- Eprint ID
- 48669
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- CaltechAUTHORS:20140819-085221671
- NSF Graduate Fellowship
- NASA Global Change Graduate Fellowship
- NASA
- NAGW-413
- Created
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2014-08-19Created from EPrint's datestamp field
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)