On the baroclinic structure of the Brazil Current–Intermediate Western Boundary Current system at 22°–23°S

Abstract

The baroclinic structure of the Brazil Current(BC)‐Intermediate Western Boundary Current (IWBC) at 22°–23°S was investigated. A reanalysis of the pioneer velocity profile measurements of the TRANSCOBRA Experiment [ Evans and Signorini , 1985 ] revealed that the BC‐IWBC system is about 75–80% baroclinic. Mapped velocity structure showed flow reversal at about 450 m, an IWBC thickness of 1200 m and core velocities exceeding 0.30 m s −1 . Total (baroclinic) transports for BC (southwestwards) and IWBC (northeastwards) were 5.6 (4.2) Sv and 3.6 (4.1) Sv, respectively. The strong baroclinic character of the BC‐IWBC system and the lack of direct velocity observations in the area yielded us to propose the use of the cross‐shelf version of the Princeton Ocean Model to generate absolute baroclinic velocities from hydrographic data. These velocities presented a similar reversal depth, and the transports of about 6–7 Sv for both BC‐IWBC were also comparable to values reported in the literature.