- Antarctic Bottom Water
The Antarctic Bottom Water (AABW) is a type of
water mass in the seas surroundingAntarctica with temperatures ranging from 0 to -0.8◦ C, salinities from 34.6 to 34.7 psu, and a density near 27.88Specify|date=August 2007.AABW is formed in the Weddell and
Ross Sea s from surface water cooling inpolynya s and below theice shelf . Surface water is enriched in salt from sea ice formation. Due to its increased density, the water is flowing down the Antarcticcontinental margin and on the bottom further north. It is the densest water in the free ocean and is overlain by the waters of theAntarctic Circumpolar Current (AACW) at a depth of 1000 to 2000 m and overliesWeddell Sea Bottom Water (WSBW) in some locations.About one-third of the northward flowing AABW enters the
Guiana Basin , mainly through the southern half of theEquatorial Channel at 35°W. The other part recirculates and some of it flows through theRomanche Fracture Zone into the eastern Atlantic. In the Guiana Basin, west of 40°W, the sloping topography and the strong, eastward flowing deep western boundary current might prevent the AABW from flowing west: thus it has to turn north at the eastern slope of theCeara Rise . At 44°W, north of the Ceara Rise, AABW flows west in the interior of the basin. A large fraction of the AABW enters the eastern Atlantic through theVema Fracture Zone .
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