A Near-Uniform Sea Level and Ocean Bottom Pressure Fluctuation and its Associated Change in Ocean Temperature over the Antarctic Continental Shelf

A spatially coherent fluctuation of sea level and ocean bottom pressure around Antarctica, known as the "southern mode", and its associated change in ocean temperature are investigated using satellite and in situ observations in conjunction with an ocean general circulation model of the Consortium for "Estimating the Circulation and Climate of the Ocean" (ECCO). The sea level fluctuation on intra-annual time-scales is barotropic and is largely confined to the Antarctic continental shelf, extending around the entire continent near-uniformly in a circumpolar manner. Winds along the continental slope surrounding the domain are responsible for this fluctuation. The circumpolar sea level fluctuation is also associated with inter-annual variations of ocean temperature. Temperature on the shelf is of particular interest for climate change due to its potential role in regulating ocean-ice sheet interaction. The relationship between sea level and temperature on the shelf could provide an alternate means for monitoring this climatologically important process that is difficult to measure. Unlike sea level, however, the temperature variation differs significantly from region to region with limited spatial extent. Mechanisms underlying these changes and the relationships between them are explored.