Studies of Circumpolar Currents

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0221369 Marshall Simple theoretical models of the Antarctic Circumpolar Current (ACC) will developed and applied to further our understanding of this central component of the global ocean circulation. The formalism of the residual mean will be exploited in an attempt to develop a theory for the stratification and overturning circulation of the ACC and how it depends on eddy transfer processes and the patterns of wind and air-sea flux acting at its surface. Specifically, solutions of the zonal-average residual mean problem will be fully explored to investigate processes that control the pattern of meridional overturning and interior stratification of the ACC. Those solutions will then be extended to 3-dimensions to explore the role of regional patterns of air-sea interaction and topographic interaction on ACC dynamics: this will be done by numerical solution of the residual mean equations in 3-dimensions. Finally, the theoretical model will diagnosed in terms of more realistic models and observations. The intellectual thrust of the proposal is that it addresses issues that are fundamental to our understanding of the general circulation of the ocean: the role and representation of the ocean's geostrophic eddy field in shaping the large-scale circulation of the ACC. It seeks to develop a simple conceptual framework that, if successful, could provide a reference point for observation and models of circumpolar flow. The study has the potential for broad impact because the ACC is a system of great importance to the global ocean and to global climate, is thought to be major player in glacial-interglacial cycles, uptake of anthropogenic CO2 and global biogeochemical cycles.