Meridional Shift of Southern Ocean Mesoscale Eddies Since the 1990s

Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean. Previous studies have documented changes in the location of temperature fronts in the Southern Ocean, but little attention has been paid to changes in the genesis locations of mesoscale eddies. Here, we provide evidence from three decades of satellite altimetry observations for the heterogeneity of the poleward shift of mesoscale activities, with the largest trend of ~0.23° ± 0.05° (10 yr)⁻¹ over the Atlantic sector and a moderate trend of ~0.1° ± 0.03° (10 yr)⁻¹ over the Indian sector, but no significant trend in the Pacific sector. The poleward shift of mesoscale eddies is associated with a southward shift of the local westerly winds while being constrained by the major topographies. As the poleward shift of westerly winds is projected to persist, the poleward oceanic heat flux from mesoscale eddies may influence future ice melt.