What is driving the fast warming rate of the Southern Hemisphere midlatitude ocean?

Significant warming has occurred across many ocean basins over the past 50-years. This has been observed through an increase in the oceanic heat content (OHC) which describes the depth integrated temperature change. The OHC trend displays a maximum value (ie. warming) in the midlatitude band stretching from 35°-50°S. However, this warming pattern is unable to be accounted for by changes in local heat fluxes. It is associated with a Sverdrup-like response to poleward strengthening winds and a poleward shift of the Southern Hemisphere supergyre and Antarctic Circumpolar Current of almost 1°. The heat required for this midlatitude warming is mostly derived from surface heat fluxes from south of 50°S, which is advected northward by enhanced Ekman transport induced by the poleward-strengthening winds. These results highlight the relationship between winds and surface heat fluxes in Southern Hemisphere midlatitude oceans.