Atmosphere Ocean Science Student Seminar

Three-dimensional Residual Circulation of the Southern Ocean

Speaker: Madeleine Youngs, MIT

Location: Warren Weaver Hall 1314

Date: Friday, October 25, 2019, 3:45 p.m.

Synopsis:

The Southern Ocean plays a major role in the global air-sea carbon fluxes, with some estimates suggesting it takes up 40\% of the total anthropogenic carbon dioxide. Understanding the Southern Ocean residual transport is particularly important because the residual transport fluxes tracers between the depth and the surface.  Recent work shows that this vertical transport preferentially occurs downstream of bottom topography, but there is further work to understand how and why this transport occurs where it does.   This study uses a re-entrant MITgcm channel to examine where the three-dimensional residual transport is concentrated and why.  An analysis of thickness-weighted average velocities highlights the relative importance of different dynamical processes, such as baroclinic eddies and the geostrophic flow.  Eddy momentum fluxes are also found to be critical for driving the vertical transport, something not considered in the traditional view of the Southern Ocean.  The localization of the vertical flow shows the necessity of highly focused observations in the Southern Ocean to understand the transport.