Using the alongshore transports between A17 and the continental slope as an approximation of the boundary currents, the damping and reinforcing effects of the thermohaline mode on the alternate boundary currents of the different wind regimes in the upper layer, were quantified. In the northern subequatorial region, the thermohaline modification leads to an alongshore transport in the upper ocean that has a direction opposed to that predicted by the wind-driven theory.

The same approach provided a large scale view of the western boundary current system from 50°S to the equator. Noteworthy are the downward extension of the Brazil Current to the base of the NADW from 28°S to about 35°S, and an intrusion of the southward Deep Western Boundary Current into the AABW at 15°S-25°S.

Four transverse samplings of the boundary flows in different wind-driven regimes show widths generally lower than 200 km in the upper layers (SACW, AAIW, UCPW). The currents are wider in the lower-deep and bottom waters. Taking into account these deep lateral shifts in the definition of the boundary currents alters their transport estimates by up to 30 per cent.