Ocean Response Along the East Antarctic Coastal Margin to the Southern
Ocean 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.