Observational aspects of the South Asian Monsoon

Seasonal evolution and spatial distribution of monsoon rainfall are influenced by land-atmosphere-ocean-biosphere interactions. Propagation of cloud systems is an important aspect of the rainfall distribution over land. In particular, the break to active monsoon transition involves northward and westward propagation of cloud bands over the Bay of Bengal. There are several hypotheses on this. Under the Indian Climate Research Programme (ICRP), efforts have been made to collect data through field experiments to understand the mechanism leading to the formation and propagation of monsoon systems, and the feedback between land and atmosphere, and atmosphere and ocean. The first part of the talk will briefly discuss the main objectives of three observational programs conducted under ICRP between 1998 and 2013, and some key results. The second part will discuss the ongoing and forthcoming field programs which are aimed at understanding the mixing mechanisms in the upper ocean and atmospheric boundary layer over the Bay.