The joint influence of topography and atmosphere on the meridional transport fluctuations in the Southern Ocean and its link with the ENSO events

Abstract

This article deals with the investigation of the influence of topography and coastlines on the dynamics of the depth averaged Antarctic Circumpolar Current (ACC), driven by wind and atmospheric pressure. This is achieved with the help of a global barotropic circulation model, under idealized and real atmospheric conditions. It is shown that the variability of meridional mass fluxes due to the atmospheric conditions over the ACC can induce short-period density anomalies in the Southern Ocean to the north in the vicinity of 47S, which can be transferred to low latitudes by the wave mechanism described by Ivchenko et al. 2004, that could have significance with respect to rapid extra-tropical oceanic links. The results of the barotropic modeling demonstrate that changes in wind strength over the ACC, together with the effect of bottom topography and coastlines, induce some meridional flow variability in the Southern Ocean, and this meridional flux variability in the Pacific Ocean is anticorrelated with the strength of the wind over the ACC. The possible link between the short-term variations of the meridional flux in the Pacific sector and the ENSO events (Southern Oscillation) is discussed.