Western Boundary Current Structure and Variability East of Abaco, Bahamas at 26.5°N

Abstract

Abstract During April 1987 to June 1988, a four-mooring, transport-resolving current meter array was deployed in a section extending 70 km eastward from Abaco, Bahamas, at 26.5°N. Mean currents in the upper layer (≤800 m) showed a clockwise rotation that appears to be associated with a small scale, quasi-permanent, anticyclonic gyre centered just northeast or the Bahamas. Deep mean currents were persistenly southward and indicated a strong, deep jet, the Deep Western Boundary Current (DWBC), reaching core speeds of 20 cm s−1at 2500 m depth about 25 km seaward of the western boundary. Vertically integrated meridional volume transport over the section showed a surprisingly large variability, ranging from approximately 20 Sv northward to 70 Sv southward (1 Sv = 106m3s−1). The mean meridional volume transport was 30 Sv to the south, with about 3 Sv flowing northward above 800 m, which could be produced by a weak Antilles Current and 33 Sv flowing, southward below 800 m. The deep southward transport of 33 Sv i...