Dynamics of Agulhas Retroflection and Ring Formation in a Numerical Model. Part II. Energetics and Ring Formation

Abstract

Rosenstiel Sch. Mar. Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA ISSN 0022-3670 J (Journal-Article) M (Marine) An energetics analysis of several numerical experiments on an idealized South Atlantic-Indian Ocean basin is presented. The model used in the experiments is the quasi-isopycnic coordinate model of Bleck and Boudra forced by wind and configured with two or three layers. The region of focus is the most dynamically active one, the Agulhas Current retroflection south of Africa, and the dynamical mechanisms associated with formation of Agulhas rings are given special attention. Whether rings form in the model and their frequency depend on two primary factors: the shape of Africa and southward inertia/baroclinicity in the overshooting Agulhas. The boundary condition on Africa (no-slip/free-slip) and horizontal resolution are also important. Experiments in which rings form exhibit considerably larger values o...