Talk by Markus Jochum

The connection between Southern Ocean winds, Atlantic Meridional Overturning Circulation and Indo-Pacific upwelling

Coupled GCM simulations are analyzed to quantify the dynamic effect of Southern Ocean (SO) winds on  transports in the ocean. It is found that the closure for skew diffusivity in the non-eddy-resolving ocean model does not allow for a realistic eddy saturation of the zonal transports in the SO in response to the wind changes, and that eddy compensation of the meridional transports in the SO is underestimated too.

Despite this underestimated eddy compensation in the SO, however, and in contrast to previous suggestions, the Atlantic Meridional Overturning Circulation (AMOC) strength is almost insensitive to SO winds. In the limit of weak SO winds the AMOC waters do not  upwell in the SO but in the tropical Indo-Pacific. Through their effect on sea-ice, weaker SO winds also lead to less production of Antarctic Bottom Water and therefore a deeper and stronger AMOC.