The time series of thermocline displacement across the North Equatorial Countercurrents are derived from pairs of Inverted Echo Sounders which straddle the countercurrent along the 28¿W and 38¿30'W meridians. The observations reported are from February to September 1983. From mid-May to the end of the record the thermocline deepens to the south and shallows to the north of the countercurrent, suggesting a continual strengthening of the countercurrent. The rate of increase of the thermocline slope at the western meridian is about twice that at 28¿W, as expected from historial data. An Empirical Orthogonal Functions (EOF) analysis of the four sounders finds the dominant mode acocunting for 64% of the variance. This is compared to an EOF analysis of model results by Philander and Pacanowski where the forcing is provided by the historial average wind field. With the model, the dominant mode is almost the entire response (92% of the variance). The time dependence of the observed mode trackes that derived from the model during the overlapping seasons.