DIRECT OBSERVATIONS OF THE CURRENT STRUCTURE EAST OF THE BAHAMAS

Quasisynoptic absolute velocity sections were obtained in the western North Atlantic to the east of the Bahamas on five cruises from 1992 to 1994, showing complex spatial and temporal variability of the current s throughout the water column. Lowered acoustic Doppler current profil ers were used on all cruises; for comparison, an acoustically-tracked free-fall profiler was used on the August 1992 and June 1993 cruises. Where simultaneous profiles from both methods are available, depth-ave raged differences are less than 0.01 m s(-1) in the ensemble mean and standard deviation. Though small, the mean difference appears to be st atistically non-zero for one of the two Doppler profilers used; no cau se has been found. The individual velocity sections show a banded stru cture of currents in the offshore direction with strong baroclinic and depth-averaged components extending over the full sampling domain. Tw o sections show a picture of the southward-flowing Deep Western Bounda ry Current (DWBC) differing from previous observations. During August 1992 and June 1993 the mean DWBC core was located more than 100 km off shore; in observations prior to 1990 it was usually near 50 km offshor e. Net southward transport below 800 m integrated from the coast to 40 0 km offshore varied from 15 to 50 Sv with a mean of about 40 Sv (1 Sv = 1 x 10(6) m(3) s(-1)). Our mean is consistent with previous estimat es; our sections add new evidence that the transport is highly variabl e to at least 400 km offshore.