The PSU/NCAR MM5 is modified for investigating the climate of northern Africa and India. Motivation behind this development is to capture smaller-scale features within the atmosphere, such as African wave disturbances and the Turkana jet, and at the surface, such as the East African topography, cold SSTs associated with upwelling, and the tight meridional temperature gradients of the Sahel. The domain is unusually large, extending from 35°S to 50°N latitude and 70°W to 155°E longitude, to reduce the dependence on lateral boundaries and to permit studies of the physical processes that connect the circulation and precipitation regimes of the West African monsoon, East Africa and the Somali jet, and the Indian monsoon.

The modifications made to MM5 to develop the tropical mesoscale climate model (TMCM) are presented, including sensitivity studies that explore the influence of surface and lateral boundary conditions, horizontal resolution, and various parameterizations. The TMCM climatology will be compared with observations, reanalysis, and GCM climatologies. The TMCM can provide distinct advantages over a GCM for studying the climate of this region, providing a superior basic-state climatology and capturing of the important physical processes. However, this is the case only when a serious model development and testing phase has been completed.