On the crossover between the Gulf Stream and the Western Boundary Undercurrent

Abstract

Abstract To determine how the Gulf Stream and Western Boundary Undercurrent cross each other near Cape Hatteras, six current meters were moored from May to July 1971 along a line normal to the Gulf Stream axis and 100 m above the ocean floor in depths from 1200 to 4200 m. Peak velocities of the six records (including one of 47 cm s −1 and the mean velocities of four of the deepest records (2800 to 4000m ) were in the southwest quadrant. During the observations the Gulf Stream did not extend to the bottom in this area except in brief current reversals to the northeast. The Western Boundary Undercurrent flowed southwest under the Gulf Stream parallel to the bottom contours. The transport of the undercurrent, estimated using two geostrophic velocity sections and deep current meter observations, was 24 × 10 6 m 3 s −1 .