2004), A comparison of tropical precipitation simulated by the NCAR Community Climate Model CCM3 with that observed by the Tropical Rainfall Measuring Mission (TRMM) satellite

This study evaluates the simulation of tropical precipitation by the Community Climate Model, version 3, (CCM3) developed at the National Center for Atmospheric Research. Monthly mean precipitation rates from an ensemble of CCM3 simulations are compared to those computed from observations of the Tropical Rainfall Measuring Mission (TRMM) satellite over a 44-month period. On regional and subregional scales, the comparison fares well over much of the Eastern Hemisphere south of 108S and over South America. However, model– satellite differences are large in portions of Central America and the Caribbean, the southern tropical Atlantic, the northern Indian Ocean, and the western equatorial and southern tropical Pacific. Since precipitation in the Tropics is the primary source of latent energy to the general circulation, such large model–satellite differences imply large differences in the amount of latent energy released. Differences tend to be seasonally dependent north of 108N, where model wet biases occur in realistic wet seasons or model-generated artificial wet seasons. South of 108N, the model wet biases exist throughout the year or have no recognizable pattern. 1