Inertial oscillations in the upper ocean during the Mixed Layer Dynamics Experiment (MILDEX)

Surface currents in the near‐inertial frequency band were analyzed from 18‐day‐long measurements taken in October/November 1983 as part of the Mixed Layer Dynamics Experiment. The currents below two drifting platforms separated by 55 km were found to have differed in their inertial response to a frontal passage on November 1 by 10 cm s −1 . Wind records from the two platforms were used to compute the predicted inertial currents with a simple slab model of the wind‐driven flow. The model currents reproduced most of the features of the observed inertial currents, including the disparity between the two locations following the November 1 frontal passage. The disparity was due to differences in the weak winds preceding the frontal passage which account for inertial currents of ∼5 cm s −1 in opposing directions at the two platforms at the time of the front. These differences, or small‐scale (∼50 km) structure in the wind field, were responsible for the disparity rather than the slight difference in the arrival time (∼2 hours) of the front at the two locations.