This research entails a hierarchy of numerical modeling studies designed to investigate fundamental dynamics of the upper ocean circulation in 3 regimes: the equatorial, coastal and subtropical oceans. The primary model to be used in this research is a nonlinear, 2 1/2-layer dynamic/thermodynamic ocean model which allows exchange of water between the 2 active layers. The study tasks are either continuations, or natural extensions, of work currently being funded by NSF (8817026 and 8912015). There are two unifying themes for much of the research: (1) understanding the dynamics of a new type of frontal instability, and (2) exploring the sensitivity of solutions to the parameterization of entrainment and detrainment physics. %%% The study contains research components that are directly applicable to all oceans, and research components that are more applicable to specific oceans. The research components directly applicable to all oceans are: (1) the investigation of the variability associated with equatorial currents, coastal currents and small-scale oceanic fronts, and (2) the study of interactions between the equatorial, coastal and subtropical ocean circulations. The research components more applicable to specific oceans are: (1) the study of the driving mechanisms of various flow patterns in the Indian Ocean, particularly in the Bay of Bengal, along the coasts of India, and near the equator, (2) the study of the New Guinea Coastal Undercurrent in the Pacific Ocean.
