The purpose of this research is to contribute to our understanding of how precipitation distributions are established over Africa and South America. The investigation will be conducted by comparisons among climate models of various degrees of complexity. Analysis will focus on understanding how the tropical atmospheric dynamics responds to specified land surface conditions and sea surface temperature (SST) anomalies, and how this response modifies precipitation patterns over land. The focus is on using climate models to illuminate physical mechanisms, not to generate the most realistic simulation possible. Experiments with a general circulation model (GCM) will be used to isolate the effects of SST distributions and land surface attributes, such as soil wetness, surface albedo and roughness, on the continental precipitation field in the tropics. A linearized version on the GCM will be used to further diagnose the GCM's response. Comparisons with more complex GCM simulations and with observations will be used to relate results to the real climate. This research is important because it attempts to enhance knowledge about how land surface properties affect climate.
