This research project will conduct studies on the larger- scale dynamics of circulations within and coupled to frictional boundary layers. One primary emphasis will be on planetary zonal scales in the tropical half of the global atmosphere. Synoptic scales and oceanic motions will be secondary themes. The approaches will be theoretical, modeling, and observational. Strong connections to GARP and TOGA programs will be maintained. Theoretical studies will have two areas of concentration. One will be on dynamic structures of balanced flows, with implications for three-dimensional data analysis strategies. Another will be on unbalanced systems, such as cross-equatorial winds, boundary-layer spin-down circulations, forced waves, and the Tibetan Plateau effect. Observational studies will use the unique GARP data. Two results on turbulent monsoonal flow in MONEX will be completed. FGGE data will be used to determine the dynamics of cross equatorial flow and air-sea momentum interactions. Modeling work will be a means to develop a TOGA (Tropical Ocean-Global Atmosphere) climate program perspective in this grant. A three- level cumulus boundary layer model will be applied to understand latitudinal and time variations, and coupled experiments with an ocean mixed layer will be conducted. Improvements in the model will include higher resolution with more realistic effects of wind shear. This research is important to advances in understanding how the earth's planetary boundary layer influences weather and climate and in modeling and predicting weather and climate.
