J.-O. Wolff

Wind-Driven Flow over Topography in a Zonal β-Plane Channel: A Quasi-geostrophic Model of the Antarctic Circumpolar Current

Abstract The paper gives a detailed account of the dynamical balance of a wind-driven zonally unbounded flow over topography. The problem is investigated with a quasi-geostrophic β-plane channel with two layers and eddy resolution. The channel has a width of 1500 km and a zonal periodicity of 4000 km. Apart from the dimensions, the model structure is similar to the one used by McWilliams et al. The experiments with this model address the problem of the relative role of transient and standing eddies as well as bottom friction and topographic form stress in the balance of a current driven by a steady surface windstress. The response of the system is investigated for different values of the friction parameter and various locations of topographic obstacles in the bottom layer of the channel. The principal momentum balance emerging from these experiments supports the concept of Munk and Palmen for the dynamics of the Antarctic Circumpolar Current, which proposes that the momentum input by windstress is transfe...

The dynamical balance of the Antarctic Circumpolar current studied with an eddy resolving quasigeostrophic model

Abstract The dynamics of a wind-driven current in a zonal channel is reviewed and investigated with a quasigeostrophic β-plane model with two layers and eddy resolution. The model structure is similar to the one used by McWilliams, Holland and Chow (1978) and the channel has dimensions of 4000 km × 1500 km. The experiments with this model address the problem of the relative role of bottom friction and bottom form drag in the balance of a current driven by a steady eastward surface windstress. The response of the system is investigated for different values of the friction parameter and various locations of topographic barriers in the bottom layer of the channnel. The principal momentum balance emerging from these experiments support the concept of Munk and Palmen (1951) for the dynamics of the Antarctic Circum-polar Current proposing that the momentum input by the windstress is transferred to the deep ocean - in the present model by vigorous eddy activity - where it may leave the system by bottom form drag. Frictional effects in the balance of the circumpolar flow may thus be of minor importance.