Seasonal transport variation in the Western Subtropical North Atlantic: experiments with an eddy-resolving model

Abstract

Uses a high resolution model of the wind driven and thermohaline circulation in the North and equatorial Atlantic Ocean to study the structure and variability of the boundary current system at 26 degrees north. The model is the first Community Modelling Effort of the World Ocean Circulation Experiment. A series of model runs examined model sensitivity to changes in wind forcing and frictional parameters. The southward volume transports in the upper 1000m of the interior Atlantic are 25.0 Sv for Hellerman-Rosenstein wind stress and 34.9 Sv for Isemer-Hasse wind stress forcing, in good agreement with the transport from the integrated Sverdrup balance at this latitude. The return flow of this wind driven transport, plus the southward transport of the Deep Western Boundary Current (6-8 Sv) is partitioned between the Florida Current and the Antilles Current. The annual variation of the simulated Florida current depends on the type of wind stress forcing used. The meridional heat transport is in phase with the Florida Current. The annual signal east of the Bahamas is masked by strong transport fluctuations on a time scale of 0 (100 days) caused by an instability of the Antilles current. (from author's abstract)