123 / 2024-09-09 09:23:38

Subpolar Southern Ocean sea level interannual variabilities and mechanisms from multi-mission satellite altimetry

Sea level change,Subpolar Southern Ocean,Southern Annular Mode

The subpolar Southern Ocean features intricate processes involving ocean dynamics and sea-ice-atmosphere interaction.  Due to insufficient observational data, the dynamic processes and their spatiotemporal variations, particularly in ice-covered regions, remain poorly understood. Based on multi-mission satellite altimetry data, we investigate the characteristics and mechanisms of interannual sea level variation in the subpolar Southern Ocean, including the ice-covered regions. Our analysis reveals that ocean surface stress curl anomaly determines sea level changes in the subpolar Southern Ocean. These anomalies are primarily influenced by wind stress curl variations resulting from shifts in wind patterns, with secondary role from sea ice drift changes. Further examination indicates that the dominant modes of sea level changes in the subpolar Southern Ocean are spatially aligned with the Southern Annular Mode (SAM). Additionally, tropical climate variability may impact sea level changes in subpolar Southern Ocean in a zonally asymmetric pattern through teleconnections. Overall, this study enhances our understanding of the interannual sea level variations in the subpolar Southern Ocean, offering valuable insights into the complex dynamics of ocean, sea-ice-atmospheric interactions in this region.