Oceanic and Atmospheric Processes in the Formation and Maintenance of the Cosmonaut Sea Deep-Water Polynya and their Relationship to Antarctic Climate

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*** 9725320 Lynch This project will apply a high resolution integrated numerical model that represents atmospheric, oceanic and sea ice processes to the maintenance of an antarctic coastal polynya. Polynyas are large recurrent areas of open water or reduced ice concentration within the winter sea ice cover. This project's study site is in the Cosmonaut Sea off East Antarctica, facing the Indian Ocean. It is conjectured that this polynya is maintained primarily by the upwelling of heat from the oceans rather than removal of ice by advection, and is formed as the result of a confluence of atmospheric preconditioning, deep ocean convection, modulated by local topographic interactions. Regularly occurring polynyas have importance in the antarctic climate system by influencing the surface exchange of heat, moisture, and momentum between the atmosphere and ocean, as well as affecting the chemical and biological composition of the ocean and sea ice. This project uses a combination of high resolution modeling and analysis of remotely sensed imagery, station observations, and experimental data to determine the mechanisms responsible for the formation of this polynya. The scale of the polynya requires the use of a high resolution limited area model, since global climate system models have neither the resolution nor the sophisticated parameterizations necessary to accurately model many of the important processes and feedbacks involved in polynya processes. This study can serve as a conceptual model for other antarctic deep water polynyas, such as the Weddell Sea polynya. ***