Characteristics of the Mean Water Vapor Transport over Monsoon Asia

Based on ECMWF monthly mean data from January 1980 to December 1989, characteristics of the three-dimensional structure of the mean water vapor transport over Monsoon Asia are described, and the more im-portant features of the different regional water vapor transport in the Indian Monsoon region and the East Asian Monsoon region are analyzed. It is found that there is a moist tongue extending from the equator poleward to the Asian Monsoon region. The three-dimensional distributions of the mean water vapor transport fields over the entire globe reflect clearly the asymmetry of the Asian Monsoon system, and the existence of a counter-Hadley monsoon circulation. The moisture conver-gence (divergence) area in Asia coincides with the confluent (diffluent) zone of the monsoon circulation. Furthermore, the moist features of the two sub-regions of the Asian Montoon area are differ-ent both in their magnitudes and in their seasonal variations.