Observations of the Pacific Equatorial Undercurrent

Abstract

WE have succeeded in measuring the flow of the Pacific Equatorial Undercurrent first described by Cromwell, Montgomery and Stroup¹. Taut-wire buoys² were anchored in 2,300 fathoms as reference points. Measurements at different depths were made by suspending a modified Roberts current meter³ from a drifting ship. A vibrotron pressure element was used to give the depth of the meter, and the drift of the ship relative to the anchored buoy was measured by radar. To define the bottom of the undercurrent four measurements were made with Swallow type neutral buoyant floats⁴. These measurements were the principal object of the Dolphin Expedition March 27–June 10, 1958, one of the special cruises of the International Geophysical Year oceanographic programme.