Water vapor and cloud feedback over the tropical oceans: Can we use ENSO as a surrogate for climate change?
Article first published online: 7 DEC 2012
Copyright 1996 by the American Geophysical Union.
Geophysical Research Letters
Volume 23, Issue 21, pages 2971–2974, 15 October 1996
How to Cite
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 19 JUL 1996
- Manuscript Received: 22 MAY 1996
Based on experiments with the Goddard Earth Observing System (GEOS) global climate model, we find that the basic patterns of anomalous water vapor greenhouse effect and cloud radiative forcing during ENSO are primarily determined by the basin-wide dynamical response to large scale sea surface temperature (SST) forcing. There is no supergreenhouse effect in the sense of unstable interaction due to local thermodynamics and water vapor radiative feedback on interannual time scales. About 80% of the clear sky water vapor greenhouse sensitivity to SST deduced from ENSO anomalies are due to the transport of water vapor by the large scale circulation. The sensitivity of water vapor greenhouse effect to SST due to radiative feedback is found to be about 1.8 Wm−2/°C, much smaller than the values of 6–9 Wm−2/°C previously estimated from satellite observations from ENSO conditions. Our results show that regionally based interannual variability should not be used to infer radiative feedback sensitivity for climate change unless proper corrections are made for the effect of the large scale circulation.