Structure of ocean circulation between the Galápagos Islands and Ecuador

Abstract

From 27 March to 5 April 2009, upper ocean velocities between the Galapagos Islands and Ecuador were measured using a vessel mounted ADCP. A region of possible strong cross-hemisphere exchange was observed immediately to the east of the Galapagos, where a shallow (200 m) 300 km wide northeastward surface flow transported 7–11 Sv. Underlying this strong northeastward surface current, a southward flowing undercurrent was observed which was at least 600m thick, 100 km wide, and had an observed transport of 7–8 Sv. Next to the Ecuador coast, the shallow (<200 m) Ecuador Coastal Current was observed to extend offshore 100 km with strongest flow, 0.33ms−1, near the surface. Immediately to the west of the Ecuador Coastal Current, flow was directed eastward and southward into the beginnings of the Peru-Chile Countercurrent.