Water vapor feedback in the tropics deduced from SSM/T-2 water vapor and MSU temperatures
- NASA Marshall Space Flight Center, Huntsville, AL (United States)
- Nichols Research Corp., Huntsville, AL (United States)
In simulations of the atmospheric response to increases in surface temperature or radiative forcing by CO{sub 2}, water vapor is usually found to produce a large positive feedback. In studies using the NCAR Community Climate Model (CCM2), it was found that the dependence of clear sky outgoing longwave radiation on sea surface temperature (SST) was almost a factor of two less with water vapor feedback included. However, other studies have provided negative vapor feedback results. Because the outgoing longwave radiation can be computed given tropospheric temperature and water vapor profiles and surface temperature, it is proposed to use satellite measurements that are primarily sensitive to these quantities. This paper discusses the method and preliminary results obtains from four satellite instrument types used to gather data on tropical SSTs between 1992 and 1995. So far, evidence from the new microwave water vapor retrievals indicates that most of the tropical upper troposphere is quite dry, with the most frequently occurring relative humidity near 10%. The hypersensitivity of clear sky outgoing longwave radiation to humidity changes at low relative humidity suggests that the tropical subsidence zones could have a controlling influence on water vapor feedback. 16 refs., 3 figs.
- OSTI ID:
- 535144
- Report Number(s):
- CONF-960146-; TRN: 97:005075-0005
- Resource Relation:
- Conference: 7. American Meteorological Society (AMS) symposium on global change studies, Atlanta, GA (United States), 28 Jan - 2 Feb 1996; Other Information: PBD: 1996; Related Information: Is Part Of Seventh symposium on global change studies; PB: 205 p.
- Country of Publication:
- United States
- Language:
- English
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