Upper ocean thermal and flow fields at 0°, 28°W (Atlantic) and 0°, 140°W (Pacific) during 1983–1985

Abstract

Moored current and temperature measurements were recorded simultaneously for 2 years (August 1932–July 1985) at six or seven depths between 10 and 250 m on the equator at 28°W in the Atlantic and at 140°W in the Pacific. The mean depth of the 20°C isotherm, which was representative of thermocline displacements, was identical at both sites. Substantially different annual cycles of the thermal and flow field at 28°W and 140°W represent an enigma. The annual variation of the 20°C isotherm was much less at 140°W than at 28°W. The annual cycle of the Equatorial Undercurrent core speed was much more pronounced at 140°W than at 28°W. The annually modulated 20- to 30-day meridional current oscillation had a larger amplitude and occurred for a longer duration at 140°W than at 28°W.