At a recent workshop organized by the World Climate Research Program (WCRP) on cloud processes and cloud feedbacks, a conclusion was that “reducing the uncertainty in cloud-climate feedbacks is one of the toughest challenges facing atmospheric scientists.” In response, the Climate Variability (CLIVAR) working group on climate models proposed to coordinate research with the aim to systematically investigate cloud feedbacks in general circulation models (GCMs).

We analyze the results of a Sea-Surface Temperature (SST) perturbation experiment on the climate of the Colorado State University General Circulation (CSU GCM), for July. This experiment, first reported by Cess (1988,1990) is the simplest experiment called for by the CLIVAR Implementation Plan. Our results focus on the change in the global distribution of clouds due to the SST increase/decrease, as produced by the ISCCP (International Satellite Cloud Climatology Project) simulator developped by Webb et al. (2001).

Cess, R. D., and G. L. Potter, 1988: A methodology for understanding and intercomparing atmospheric climate feedback processes in GCMs. J. Geophys. Res., 93, 8305-8314.

Cess, R. D., and co-authors, 1990: Intercomparison and interpretation of cloud-climate feedback processes in nineteen atmospheric general circulation models. J. Geophys. Res., 95, 16601-16615.

Webb, M., C. Senior, S. Bony, and J.-J. Morcrette, 2001: Combining ERBE and ISCCP data to assess clouds in the Hadley Centre, ECMWF, and LMD atmospheric climate models. Climate Dynamics, 17, 905-922.