Mesoscale motions near the deep western boundary of the North Atlantic

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Three SOFAR floats set at the end of the Mid-Ocean Dynamics Experiment (MODE-1) in the western North Atlantic drifted westward out of the MODE area after several years and into a region near the western boundary of the basin. The floats were at a depth of 1500 to 2000 m. Two of the floats crossed the tip of the Blake-Bahama Outer Ridge, were caught in an intense, cyclonic eddy with a radius of approximately 40 km and orbital speeds reaching nearly 40 cms-1, and moved rapidly south along the Blake Escarpment. The third float moved several hundred kilometers northwest of the MODE area, back to the south across the Blake-Bahama Outer Ridge, and then south along the Blake Escarpment. The measurements indicate that, at the depth of the floats, a deep, south-flowing jet, estimated to be at most 60 km wide, is present along the Blake Escarpment but is intermittent or non-existent along other portions of the boundary farther south. Though the floats were everywhere several thousand meters above the bottom, the influence of local topographic features is evident, and the tracks differ markedly in regions of the ocean separated by only a few hundred kilometers. © 1978.

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Deep-Sea Research