Testing Cloud Parameterizations Used in Climate Models Against Observations and High-Resolution Cloud Models

Cloud feedbacks are the single greatest unknown limiting the credibility of simulations of anthropogenic climate change. Current research is aimed at evaluating the physical realism of the cloud parameterizations used in climate models. These evaluations are of course fundamentally based on comparison with observations, including both field data and satellite data. In addition,results from high-resolution cloud models are being combined with observations to provide more stringent tests of cloud parameterizations. This paper will summarize recent work in this area, with emphasis on the evaluation of models through the use of observations obtained through the U.S. Department of Energy's ARM ("Atmospheric Radiation Measurements") Program. We will also discuss recent suggestions by W. Grabowski and others that the high-resolution cloud models can themselves be used as "super parameterizations" within climate models.