Dipoles of the South East Madagascar Current

Abstract

Satellite altimetry data covering 18 years together with hydrographic observations around south Madagascar show that after separation from the coast, the South East Madagascar Current (SEMC) propagates southwestward and breaks up into a regular series of symmetric counter-rotating vortex pairs. Most of them split and propagate into the Agulhas retroflection system. Interannual variability of the dipole formation is related to the El Nino-Southern Oscillation. In the observation period two "early" Agulhas retroflection events appeared both related to strong Madagascar dipoles. The symmetry of the dipoles may originate from the boundary current where negative vorticity on the inshore side is adjacent to positive vorticity further offshore. Key Points The SEMC breaks up into symmetric dipolar structures Interannual variability in the SEMC outflow is related to ENSO Only two early retroflection events occurred in the Agulhas Current in 18 years © 2013. American Geophysical Union. All Rights Reserved.