What Caused the Large-Scale Heat Deficit in the Subtropical South Atlantic Ocean During 2009–2012? Geophysical Research Letters

The subtropical South Atlantic hosts complex ocean circulation patterns and processes that transport heat to the North Atlantic, thereby playing an important role in global energy redistribution. This study uses several oceanic products to assess ocean heat changes in the subtropical South Atlantic and the associated atmosphere-ocean processes. A particular focus is placed on the large heat deficit during 2009–2012, which is associated with cooling during 2008–2011 and subsequent warming. This heat deficit was largely driven by a sharp increase in the southward Ekman transport across 35°S during 2008–2011. The anomalous Ekman transport is connected to the persistent positive sea level pressure anomaly over the Atlantic sector of the Southern Ocean, caused by the Southern Annular Mode and the Pacific-South American Modes. Although the overall correlations of these climate modes with the Ekman transport are modest during 1993–2016, the modes combined to produce large heat content anomalies during 2009–2012.