Water-vapor climate feedback inferred from climate fluctuations, 2003–2008
A. E. Dessler, Z. Zhang and P. Yang (Department of Atmospheric Sciences, Texas A&M University, College Station, TX, U.S.A.)
Abstract
Between 2003 and 2008, the global-average surface temperature of the Earth varied by 0.6°C. We analyze here the response of tropospheric water vapor to these variations. Height-resolved measurements of specific humidity (q) and relative humidity (RH) are obtained from NASA's satellite-borne Atmospheric Infrared Sounder (AIRS). Over most of the troposphere, q increased with increasing global-average surface temperature, although some regions showed the opposite response. RH increased in some regions and decreased in others, with the global average remaining nearly constant at most altitudes. The water-vapor feedback implied by these observations is strongly positive, with an average magnitude of λ q = 2.04 W/m2/K, similar to that simulated by climate models. The magnitude is similar to that obtained if the atmosphere maintained constant RH everywhere.
(Received 13 July 2008, accepted 19 September 2008, published 23 October 2008.)
(2008), Water-vapor climate feedback inferred from climate fluctuations, 2003–2008, Geophysical Research Letters, 35, L20704; doi:10.1029/2008GL035333.
Link to abstract: http://www.agu.org/pubs/crossref/2008/2008GL035333.shtml
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