Yanai proposes to continue his investigations into three related topics on the dynamics of large scale tropical motions which focus on their linkage with extratropical disturbances and with clusters of meso-convective scale cloud systems. First, the nature of heat sources to the atmosphere induced by the Tibetan Plateau and their influence on variations of the Asian monsoon are to be further diagnosed. Secondly, the interactions of the 30-60 day tropical oscillation and mid-latitude disturbances in the global flow are to be further studied. Their differences between El Nino and non-El Nino years are now to be explored. Third, the roles of downdrafts, mesoscale organization, and vertical wind shear in the cloud cluster environment are to be analyzed, to ob- tain improved statistical representation of the overall thermo- dynamic and dynamic effects of convective cloud arrays of varying types. Yanai has long been a leader in the quantitative analysis of observational data on these topics, and in the conceptual framing of the results into process descriptions that have been incorpora- ted into widely used components of numerical weather prediction and general circulation models. This work should contribute to useful advances in short-range weather prediction, as well as to a deeper understanding of longer-term variations of major features of the global general circulation.
