Evidence for Shallow Zonal Jets in the South Equatorial Current Region of the Southwest Pacific

Abstract

At depths above 1000 m, the currents of the southwestern Pacific are traditionally considered to be dominated by the broad westward flow of the South Equatorial Current, part of the South Pacific subtropical gyre. Results from the OCCAM global ocean model, reported here, indicate that in reality the South Equatorial Current is broken up into a series of zonal jets by the extensive shallow topography associated with islands and reefs. This paper discusses the large-scale structure of the jets and their effect on the temperature and salinity fields. It is shown that some of the jets advect cores of high or low salinity water, which may be used experimentally to identify the jets and their pathways. Comparisons with hydrographic observations show some agreement with the model results but a more detailed experimental program is required.