Sea level changes forced by Southern Ocean winds

Abstract

On regional scales, changes in sea level are significantly affected by local dynamical changes. Westerly winds over the Southern Ocean have been strengthening and shifting southward in recent decades, and this change is projected to continue in the future. This study applies wind forcing anomalies to an eddy-permitting ocean model to study the dynamical response to a Southern Hemisphere westerly wind increase and/or southward shift. It is shown that the applied wind anomalies result in a change in sea surface slope across the Antarctic Circumpolar Current such that a fall in sea level occurs around the Antarctic continental margin. The Antarctic Circumpolar Current transport and regional sea level are particularly sensitive to latitudinal shifts in the wind, with a much more muted response found when only wind strengthening is applied. In addition to the local sea level changes, Southern Ocean winds also have a global effect through changing ocean heat content and the global overturning circulation.