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Circulation and transports in the N ewfoundland B asin, western subpolar N orth A tlantic
Author(s) -
Mertens Christian,
Rhein Monika,
Walter Maren,
Böning Claus W.,
Behrens Erik,
Kieke Dagmar,
Steinfeldt Reiner,
Stöber Uwe
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc010019
Subject(s) - ocean gyre , geology , north atlantic deep water , oceanography , boundary current , hydrography , current (fluid) , water mass , submarine pipeline , ocean current , continental shelf , circumpolar deep water , thermohaline circulation , climatology , subtropics , fishery , biology
The southwestern part of the subpolar North Atlantic east of the Grand Banks of Newfoundland and Flemish Cap is a crucial area for the Atlantic Meridional Overturning Circulation. Here the exchange between subpolar and subtropical gyre takes place, southward flowing cold and fresh water is replaced by northward flowing warm and salty water within the North Atlantic Current (NAC). As part of a long‐term experiment, the circulation east of Flemish Cap has been studied by seven repeat hydrographic sections along47 ° N (2003–2011), a 2 year time series of current velocities at the continental slope (2009–2011), 19 years of sea surface height, and 47 years of output from an eddy resolving ocean circulation model. The structure of the flow field in the measurements and the model shows a deep reaching NAC with adjacent recirculation and two distinct cores of southward flow in the Deep Western Boundary Current (DWBC): one core above the continental slope with maximum velocities at mid‐depth and the second farther east with bottom‐intensified velocities. The western core of the DWBC is rather stable, while the offshore core shows high temporal variability that in the model is correlated with the NAC strength. About 30 Sv of deep water flow southward below a density of σ θ = 27.68 kg m −3 in the DWBC. The NAC transports about 110 Sv northward, approximately 15 Sv originating from the DWBC, and 75 Sv recirculating locally east of the NAC, leaving 20 Sv to be supplied by the NAC from the south.