Ocean Response Along the East Antarctic Coastal Margin to the Southern Annular Mode

Abstract Ocean circulation around the Antarctic coastal margins plays a critical role in heat delivery to Antarctica, melting ice shelves. However, until recently, satellite‐based sea‐level observations have been limited by the presence of sea ice. With improved algorithms, it is now possible to monitor sea‐level fluctuations over most of the Southern Ocean, including sea ice‐covered areas. We identified several clockwise gyres along East Antarctic coastal margins in satellite‐derived dynamic ocean topography (DOT). Singular value decomposition analyses revealed that the coastal DOT deepening and anomalous clockwise circulation consistently occur during the positive phase of the southern annular mode (SAM), which is associated with negative wind stress curl anomalies. Shifting of the SAM to a more positive phase since the 20th century and its expected continuation into the coming century could lead to enhanced clockwise gyres along East Antarctica, contributing to increased poleward ocean heat transport.