The role of eddy transfer in setting the stratification and transport of a circumpolar current

Abstract

High resolution numerical experiments of a circumpolar current are diagnosed to study how lateral and vertical transfer of buoyancy by geostrophic eddies balances advection by a meridional circulation driven by surface wind stresses and buoyancy fluxes. A theory is developed in the framework of the "residual circulation" to relate the vertical and horizontal stratification set up to the transfer properties of eddies and the patterns of imposed wind and buoyancy forcing. Simple expressions are found for the depth of penetration, stratification, baroclinic transport, and residual circulation of the current. Finally, the ideas are applied to the Antarctic Circumpolar Current (ACC) and yield predictions for how its properties depend on wind and buoyancy forcing.