Characteristics of eddies shed from the Antarctic Circumpolar Current

Winter temperatures in the western Antarctic peninsula (WAP) region are the fastest-warming temperatures on Earth, however understanding the heat sources driving the rise in temperatures remains an open research question.  The only heat source with sufficient heat to account for the atmospheric warming is found in the deep waters of the Circumpolar Deep Current (CDW).  This offshore delivery of heat to the coastal regions is thought to be provided in the form of eddies shed off the Antarctic Circumpolar Current (ACC). It has been suggested that Marguerite Trough provides a path for CDW intrusions to follow from the shelf break to Marguerite Bay. Data from moorings located on both the eastern and western boundaries of Marguerite Trough indicate that warm water moves along the trough as distinct bursts occurring an average of four times per month between about 200 m and 400 m depth. In this study, autonomous Webb glider observations along the WAP continental shelf region are used to examine the spatial extent of eddies shed from the ACC. In each of two deployments (austral springs 2010/11 and 2011/12), gliders traveled southward along the peninsula and encountered distinct water masses with properties typical of CDW, allowing estimates of the spatial scale of these features. During the second deployment (Nov. 2011 - Jan. 2012), the glider encountered two of these features more than once, allowing estimates of the transport speed and rate of decay of the eddies. These high-resolution observations may fill the gap in our understanding of the heat budget of this important region.