Abstract
Historical data from about 500 surface moorings are used to describe the mean and half-yearly averaged circulation of the Equatorial Atlantic. The emphasis is on the kinematic structure and transports of equatorial countercurrents and undercurrents. West of 30° W they form a single eastward flow between 5° S and 10° N penetrating to the depth of 1500 m. The total transport of this flow is more than 90 Sv. There are three subsurface cores in this eastward flow located approximately at 5° S, at the Equator and at 5° N. The typical velocities are 20, 50 and 30 cm/s respectively. The typical velocity in the Equatorial Undercurrent (EU) deep core is about 20 cm/s. East of 30° W the single eastward flow is separated by two branches of the South Equatorial Current (SEC) flowing westward along 3 to 4° S and 2 to 4° N. This westward current, with maximum velocities of about 30 to 40 cm/s in the subsurface layers, penetrates to a depth of 1000 m. Proceeding to the east, the cores of the North Equatorial Countercurrent (NECC), EU and the South Equatorial Countercurrent (SECC) rise toward the surface and become wider and weaker. Their total transport decreases to about 75 Sv at 22.5° to 25° W. The EU is the strongest of these currents. The volume transport of the NECC is reduced from 30 Sv in the western part to 20 Sv in the eastern part of the Equatorial Atlantic (±10 to 15 per cent).
Published Version
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