Injection of Antarctic Intermediate Water into the Atlantic subtropical gyre in an eddy resolving ocean model

Abstract

Antarctic Intermediate Water (AAIW) injection mechanism into the Atlantic subtropical gyre at the Brazil-Malvinas (B/M) Current confluence is investigated by using an eddy resolving ocean model. The temporal residual-mean (TRM) velocity framework is used to evaluate transport due to eddies. It is found that the AAIW injection is caused by eddy-induced transport. A low potential vorticity (PV) water in Malvinas Current generated in the southeast Pacific and near Burdwood Bank encounters the Brazil Current at the B/M confluence, which has relatively high PV value. Since stirring of eddies transports low PV water into high PV water region, the low PV water in Malvinas Current is injected into Brazil Current. The downward TRM velocity exceeds 3 × 10-5 ms-1 at the confluence, which represents strength of the injection. This strong downward transport forms the low salinity tongue of the Atlantic AAIW in this eddy-resolving ocean model. Copyright 2008 by the American Geophysical Union.