HR: 15:10h
AN: OS13D-07    [Abstracts]
TI: Meanders Downstream the Agulhas Retroflexion.
AU: * Ochoa, J
EM: jochoa@cicese.mx
AF: DOF/CICESE, Km 107, Carr. Tijuana-Ensenada, Ensenada, BC 22800 Mexico
AU: Niiler, P P
EM: pniiler@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0213 United States
AB: The Agulhas Current is a jet in the Eastern Indian Ocean that suffers a dramatic anticyclonic turn once it advances over the southernmost latitude of the African continent. From flowing poleward and parallel to the coast in a southwestward direction turns into an eastward direction, followed by large meanders. The global drifter program allows an estimation of these features in the mean surface flow and the variability. We do an analysis of five meanders, their wavelength is about 700 km, and their amplitude decrease from 170 km in the first one to 50 km in the following. Theories of the main expected dynamical balance in steady or quasi-steady geophysical jets had been around for 40 years. Conservation of potential vorticity, and therefore neglect of dissipative processes, being at the core of these theories. Here we show that the large meanders follow a simple vorticity balance, in agreement with such theories, where the planetary vorticity and curvature of the flow add up to a constant along pathlines. We argue on the low influence of the Reynolds stresses given the ratio of eddy and mean kinetic energy.
DE: 4508 Coriolis effects
DE: 4512 Currents
DE: 4524 Fine structure and microstructure
DE: 4576 Western boundary currents
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting