Open AccessPath of the North Atlantic Deep Water in the Brazil Basin
Author(s) -
Zangenberg Norbert,
Siedler Gerold
Publication year - 1998
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/97jc03287
Subject(s) - north atlantic deep water , geology , boundary current , geostrophic wind , water mass , hydrography , oceanography , ridge , latitude , thermohaline circulation , ocean gyre , potential vorticity , gulf stream , mid atlantic ridge , climatology , ocean current , vorticity , subtropics , vortex , geography , geodesy , meteorology , paleontology , fishery , biology
Recent hydrographic sections and high‐quality historical data sets are used to determine geostrophic currents at subtropical latitudes in the western basin of the South Atlantic. Levels of no motion are determined from water mass information and a mass balance constraint to obtain the transport field of North Atlantic Deep Water (NADW) in this region. The incoming NADW transport of about 20 Sv from the north at 19°S appears to be balanced by only one third of this transport leaving in the south and two thirds leaving to the east or northeast at the Mid‐Atlantic Ridge. A simple model is proposed to determine the cause of the NADW branching. It is shown that potential vorticity preservation in the presence of topographic changes leads to a similar flow pattern as observed, with branching near the Vitória‐Trindade‐Ridge and also an eastward turning of the southward western boundary current at about 28°S, the latitude where a balance of planetary vorticity change and stretching can be expected.