A subsurface north equatorial countercurrent in the eastern pacific ocean

Abstract

In the eastern Pacific Ocean an eastward countercurrent is found in the subsurface layers at 3°–6°N, just to the south of the North Equatorial Countercurrent in the shallower surface layers. Data from the Eastropac expedition (1967–1968) indicate that the subsurface countercurrent is remarkably stable and persists at about the same latitude in all seasons of the year at least between 119°W and 98°W. At 119°W the maximum eastward geostrophic speed is about 30 cm/sec and occurs at 170–180 cl/t of thermosteric anomaly (actual depth 100–200 meters); the width of the countercurrent is 110–160 km, and the average eastward transport is estimated to be 32 km3/hr (9 × 106 m3/sec).