Title: The meandering pathways (zonal asymmetry) of the Southern Ocean overturning circulation: some results from the SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) program
Abstract: 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 has not been melting back at a large rate, surface waters are not necessarily warming, and carbon may be outgassing from the deep ocean at greater rates than hitherto expected. These processes are strongly affected by the southeastward spiraling pathway of the Antarctic Circumpolar Current (ACC) and its interactions with topography, and the pathway of Deep Water upwelling through the ACC. This spiraling pathway is not uniformly southeastward nor is upwelling along the pathway uniform: the locations where carbon-rich upwelled water reaches the surface are strongly steered by topography and by the subpolar Ross and Weddell gyres, while upwelling itself is enhanced by strongly localized eddy fields 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.