Downscaled climate and streamflow study of the southwestern United States

Downscaling coarse resolution climate data to scales that are useful for im pact assessment studies is receiving increased attention. Basin-scale hydro logic processes and other local climate impacts related to water resources such as reservoir management, crop and forest productivity, and ecosystem r esponse require climate information at scales that are much finer than curr ent and future GCM resolutions. The Regional Climate System Model (RCSM) is a dynamic downscaling system that has been used since 1994 for short-term precipitation and streamflow predictions and seasonal hindcast analysis wit h good skill. During the 1997-1998 winter, experimental seasonal forecasts were made in collaboration with the NOAA Climate Prediction Center and UCLA with promising results. Preliminary studies of a control and 2xCO(2) pertu rbation for the southwestern U.S. have been performed.