This research is a continuation and extension of an existing project on the study of dynamics of tropical intraseasonal oscillation. The objective of the study is to enhance physical understanding of the complex behavior of intraseasonal disturbances in spatially varying mean tropical circulations, their interactions with the oceanic mixed layer and their roles in ENSO (El Nino-southern Oscillation) evolution. Three research thrusts are proposed: a) Effects of mean tropical circulation on dynamics of the intraseasonal disturbances; b) Intraseasonal variations of air-sea interface variables and oceanic influence on atmospheric intraseasonal disturbances; c) Response of ocean to intraseasonal variation of surface winds and the links between intraseasonal and interannual variations. The PI will adopt a combination of theoretical and empirical analysis. A free atmosphere-boundary layer coupled model developed in the existing project will be extended to include basic flow and coupling with an ocean mixed layer model, forming a dynamics framework for theoretical analysis. Interim COADS ship reports (1980-1987) generated by global data assimilation systems of th European Center for Medium Range Weather Froecasts (ECMWF), and sea-level data collected at the TOGA Sea Level Center (1975-1987) will be used for diagnostic studies. This research is important because it attempts to increase the level of understanding of climate processes that influence climate variability around the world.
