Observed effect of an eddy on inertial oscillations

Of the many current measurements made by the Woods Hole Oceanographic Institution, one set, made at Site D, 39°N, 70°W, in the fall of 1969, has a double peak in its energy spectrum, one on each side of the local inertial frequency. Coincident with these current records were expendable bathythermograph and infra-red aircraft observations indicating the presence of an anticyclonic eddy that drifted through the observing site. The observed split in the inertial peak of the current records is attributed to variations in the effective inertial frequency caused by the vertical component of vorticity associated with the eddy.