The Role of Svredrup Balance on the Antarctic Circumpolar Current Dynamics

Eddy-permitting simulations are used to show that Sverdrup balance can be observed in the large scale flow of a wind-driven channel with a meridional topographic ridge. This is confirmed using both 2-layer quasigeostrophic and 25-level primitive equation models at high horizontal resolution. How baroclinic transport depends on the wind stress amplitude, τ, is compared for flat bottom ridge topographies. While in the flat bottom case, transport obeys a τ^0.2 power law, in the topographic ridge case, transport is independent of the wind stress amplitude. This transport saturation occurs in conjunction with the development of Sverdrup gyres in the large scale barotropic streamfunction. This suggests that in the saturation regime, additional wind forcing serves to feed these gyres as opposed to feeding the circumpolar transport. To support this hypothesis, robustness experiments are performed varying the channel length, the bottom friction, and the relative amount of wind stress to wind stress curl.