No abstract

The distribution of temperature, salinity, and oxygen in the western equatorial Atlantic, combined with parachute drogue observations and an analysis of the pressure fields in the upper 300 meters, shows the current pattern associated with the origin of the Equatorial Undercurrent. The temperature/oxygen relationship indicates that most of the Undercurrent water comes from the South Atlantic by way of the North Brazilian Coastal Current and that the contribution of North Atlantic water is very minor.

No abstract

Direct‐current measurements during March and April 1970, in the four major passages through the Lesser Antilles show a westward transport of about 26 × 106 m3 sec−1. This transport is divided between the Grenada, St. Vincent, and St. Lucia passages with, respectively, 10, 10, and 6 × 106 m3 sec−1 flowing to the west. The transport through Dominica passage was less than 2 × 106 m3 sec−1 during these measurements. This flow pattern is consistent with the distribution of variables as shown by data from hydrographic stations to the east and west of each passage. On the basis of the temperature‐oxygen relationship, water that enters the Caribbean with a temperature between 16°–23°C comes from a broad band of water found east of the area.

Recent measurements in the equatorial Atlantic from 10øW to 20øW longitude have confirmed the suspected existence of a shallow easterly undercurrent similar to the Cromwell current in the Pacific Ocean. The core of the undercurrent lies at a depth of about 60 meters, and it appears to be about 300 kilometers wide and more or less symmetrically located about the equator. At a depth of 100 meters measurements indicated an easterly current velocity of 130 cm/sec relative to a weak westerly surface drift of 10 to 20 cm/sec. Temperatures and oxygen profiles were markedly similar to those reported for the Cromwell current. The salinity profiles were different; they showed a well developed high-salinity core which was not present in the Pacific. It is suggested that the source of the high salinity is the large reservoir of very saline water lying close to the South American continent south of the equator.