Physical oceanography in the Scotia Sea during the CCAMLR 2000 survey, austral summer 2000

In January and February 2000, four ships conducted an extensive hydrographic survey of the Scotia Sea as part of the CCAMLR 2000 Survey. There were 169 CTD stations to at least 1000 m depth, making this the largest synoptic dataset since 1981. A hydrographic section at Drake Passage was used to define water masses and ocean fronts. In 2000, the Subantarctic Front and the Polar Front were unusually close, and the entire survey occurred to the south of the Polar Front. The survey area was bisected by the Subantarctic Circumpolar Current Front and the Southern Boundary of the Antarctic Circumpolar Current. In Drake Passage, these fronts were widely spaced. A further two hydrographic sections to the east of Drake Passage show that the relative location of these fronts changes east of Drake Passage. Horizontal maps across the survey area show that close to Drake Passage, properties are aligned in a southwest to northeast direction. At approximately 35°W, properties become orientated in a north–south direction. A map of geopotential anomaly shows the flow field across the survey area and allows identification of oceanic fronts. In months previous to the survey, the giant icebergs A22B and B10A crossed the Scotia Sea and closely followed the geopotential field from the CCAMLR 2000 dataset. The SACCF is not the only important front for transporting biological matter from the Antarctic Peninsula to South Georgia; an interaction between the SBACC and the SACCF is also likely to be important.