On the Factors Controlling the Eddy-Induced Transport in the Antarctic Circumpolar Current

Abstract

Abstract This study examines eddy-driven material transport by analyzing trajectories of Lagrangian particles in an idealized model of the Southern Ocean. The main focus is on the direction of the transport in the latitude–depth plane, as well as on the magnitudes of the vertical and meridional particle dispersion. In particular, this transport is along the mean isopycnals in the control simulation, but changes its direction and intensity in a series of sensitivity experiments with artificially modified currents. The main new conclusion is that the direction of the transport is determined by the three-dimensional interplay between the zonal background flow and the transient eddies; the stationary meanders play a secondary role. The key parameter here is the strength of the zonal advection relative to the eddy magnitudes, whereas the mean vertical shear in the zonal velocity is of secondary importance. In particular, stronger mean zonal advection leads to steeper orientation of the eddy fluxes and deeper penetration of tracer anomalies.