CASPO Seminar: Andrew Stewart

05/02/2018 - 3:30pm

Topic: Dynamics of heat transfer and exchanges across the Antarctic Slope Front

Abstract: The Antarctic Slope Front (ASF) serves as a dynamical barrier separating the cold waters of the Antarctic continental shelf from the warmer waters of the open Southern Ocean. It therefore mediates the export of Antarctic Bottom Water to the global abyss and the delivery of heat to Antarctica’s floating ice shelves, a process that is accelerating land-based ice loss in various sectors of the continent. This seminar will review current understanding of the role of the ASF in near-Antarctic and global ocean circulation, with an emphasis on recent work that points to a prominent role for high-frequency variability, most notably eddies and tides, in modulating cross-ASF exchanges. The small scales (<20km) at which the resulting exchanges occur has historically limited our understanding via both direct measurements and modeling approaches, particularly in their contribution to continental-scale processes. Our work aims to close this gap in understanding using a high-resolution (1/48th degree) global ECCO2 simulation that resolves high-frequency exchanges across the ASF around the entire continent. We quantify the relative roles of tides, eddies and mean flows in exchanging heat across the continental shelf and slope, and the spatial localization of this heat transport. We then provide insight into the processes controlling cross-slope exchange by using energy and vorticity budgets to characterize interactions between tides, eddies, the oceanic mean flow and the overlying sea ice. Finally, we discuss ongoing avenues of research into the dynamics of the ASF and heat/tracer budgets around the entire Antarctic continent.

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Ratnaksha Lele
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Nierenberg Hall 101