Numerical study of orographic-convective precipitation over the eastern Arabian Sea and the Ghat Mountains during the summer monsoon

Abstract

When the western coast of India lies in the path of the low-level west-southwest wind crossing the Arabian Sea during the summer monsoon season, deep convection frequently develops over the ocean off the coast. In such a situation, the maximum rainfall occurs near the coast, not over the Western Ghats. In order to study the physics underlying orographic-convective precipitation over this area, a two-dimensional compressible moist cloud model is applied. The model is written in terrain-following coordinates and includes the Coriolis force and a planetary boundary layer parameterization. It is concluded that, in order to account for the observed features of rainfall two factors, the strongly sheared environment and fluxes of latent and sensible heat from the ocean, are essential. -from Authors