Absolutely referenced geostrophic velocity and transport on a section across the North Atlantic Current

Document Type

Article

Date of Original Version

2-1-2000

Abstract

A transect of CTD profiles crossing the North Atlantic Current (NAC) along WOCE line ACM6 near 42.5 °N during August 1-7, 1993, provides geostrophic shear velocity profiles, which were absolutely referenced using simultaneous POGO transport float measurements and velocity measurements from a ship-mounted acoustic doppler current profiler (ADCP). The NAC absolute transport was 112 ± 23 x 106 m3 s-1, which includes a portion of the transport of the Mann Eddy, a large permanent anticyclonic eddy commonly adjacent to the NAC. The NAC transport estimated relative to a level of no motion at the bottom would have underestimated the true total absolute transport by 20%. A surprisingly large 58 x 106 m3 s-1 flowed southward just inshore of the NAC. This flow, centered near 1500 dbars about 200 km offshore of the shelf-break, was fairly barotropic with a peak velocity of greater than 20 cm s-1, and the water mass characteristics were of Labrador Sea Water. These absolute transport observations suggest southward recirculation inshore of the NAC at 42.5 °N and a stronger NAC than has previously been observed.

Publication Title, e.g., Journal

Deep-Sea Research Part I: Oceanographic Research Papers

Volume

47

Issue

2

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