"The Changing Climate of the Southern Ocean: Influcence of the Meandering Pathway of the Antarctic Circumpolar Current"
The Southern Ocean is a region of potentially dramatic climate change impacts, due to the large amount of freshwater tied up in the Antarctic ice sheet and the potential for sea level rise accompanying loss of that ice. It is the region of the largest deep ocean heat gains of the global ocean, likely due to changes in production of dense waters in coastal regions of Antarctica. It is also a region of climate change surprises, where sea ice cover is slightly advancing rather than retreating, surface waters are not necessarily warming, and carbon may be outgassing from the deep ocean at greater rates than hitherto expected. These eects can largely be attributed to strengthened winds, which enhance upwelling of deep waters to the sea surface. Southeastward and upward spiraling of northern deep waters into the Southern Ocean and through the Antarctic Circumpolar Current (ACC) brings the cool, but not freezing, deep waters to the Antarctic margin in the regions where the overlying ice shelves are losing the most mass. This spiraling pathway is not uniformly southeastward nor is upwelling along the pathway uniform: the location of the fronts where carbon-rich upwelled water reaches the surface is strongly steered by topography and by the subpolar Ross and Weddell gyres, while upwelling itself is enhanced by strongly localized eddy elds where the ACC crosses major topography. The pattern of topographically-steered meanders of the ACC dictates the regions where winter sea ice is expanding versus contracting in response to stronger winds.
About the Speaker
Lynne Talley is a Distinguished Professor of Physical Oceanography in the Climate, Atmospheric Sciences, and Physical Oceanography division at Scripps Institution of Oceanography, University of California, San Diego.
Talley’s research focuses on the general circulation of the ocean and the role of various oceanic and atmospheric conditions that affect ocean currents and property distributions, including salinity. Her work involves analysis of data from most of the world’s oceans, depicting the movement of heat, salinity, and water masses, and the formation of water masses, particularly in subpolar regions.
About this Series
The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars generally take place on Monday from 12-1pm. Lunch is provided to encourage students and post-docs to meet with the speaker. Besides the seminar and lunch, individual meetings with professors, post-docs, and students are arranged.