Anticyclonic eddies generated near the corner rise seamounts

Abstract

During 1977 two freely drifting buoys, originally in the Gulf Stream, looped over and in the lee of the Corner Rise seamounts. The trajectories suggest that by mid-August an anticyclonic eddy was generated over the seamounts, where it remained for six weeks. During the period October-December it left the seamounts and drifted southwestward with a mean speed of 5 em/sec. The eddy was characterized by a clockwise circulation with speeds of 30 em/sec and an overall size of 200 km. An XBT survey showed that the eddy contained a warm core manifested by a depression of the main thermocline; at the center the 15• isotherm was located ·at a depth of 715 m. During the period June-August a third buoy looped in a second anticyclonic eddy which also drifted southwestward in the lee of the Corner Rise. The implication of these measurements is that, every few months, warm core eddies form near the Corner Rise and that they subsequently drift southwestward forming a wake region downstream of the seamounts.