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Distribution of tropical tropospheric water vaporUtilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence that constrains the turbulent downgradient mixing to within the convective boundary layer and effectively dries the troposphere through downward advection, it also pumps hydrometeors into the upper troposphere, whose subsequent evaporation appears to be the major source of moisture for the large-scale subsiding motion. The development of upper-level clouds and precipitation from these clouds may also act to dry the outflow, thus explaining the low relative humidity near the tropopause. A one-dimensional model is developed to simulate the mean vertical structure of water vapor in the tropical troposphere. It is also shown that the horizontal variation of water vapor in the tropical troposphere above the trade-wind boundary layer can be explained by the variation of a moisture source that is proportional to the amount of upper-level clouds. Implications for the nature of water vapor feedback in global warming are discussed.
Document ID
19930062780
Document Type
Reprint (Version printed in journal)
Authors
Sun, De-Zheng (NASA Headquarters Washington, DC United States)
Lindzen, Richard S. (MIT Cambridge, MA, United States)
Date Acquired
August 16, 2013
Publication Date
June 15, 1993
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 50
Issue: 12
ISSN: 0022-4928
Subject Category
METEOROLOGY AND CLIMATOLOGY
Funding Number(s)
CONTRACT_GRANT: NAGW-525
CONTRACT_GRANT: NSF ATM-85-20354
Distribution Limits
Public
Copyright
Other