Observations of annual and El Nino thermal and flow variations at 0 deg, 110 deg W and 0 deg, 95 deg W during 1980-1985

The paper describes the low-frequency (i.e., time scales longer than a month) upper ocean (above 250 m) current and temperature moored measurements conducted from March 1980 to September 1985 at 0, 110 deg W and from July 1981 to November 1983 (i.e., including the period of the 1982-1983 El Nino) at 0, 95 deg W. Estimates of the annual cycle were removed from the observations to determine the current and temperature fluctuations due to the 1982-1983 El Nino. The circulation of the upper ocean was found to be dramatically altered during the El Nino: the normally westward flowing surface current in autumn months reversed direction, and the equatorial undercurrent, normally considered to be a permanent feature, disappeared. Associated with the El Nino was a massive redistribution of heat throughout the mixed layer and the thermocline.