On the Decay of the Meanders of Eastward Currents

Abstract

The separation of western boundary currents from the coast and their eastward extensions into the open ocean are characterized by the presence of quasi-stationary, large-scale meanders. These meanders result when the western boundary current overshoots the latitude of zero wind-stress curl. The wavelength and the scale of decay of those meanders have previously been estimated by considering the superposition of a westward Rossby wave and an eastward mean flow. While observations indicate that the wavelength of the meanders is in good agreement with theory, the decay scale is much shorter than that indicated by scaling arguments. The purpose of this article is to show that the rapid decay of the meanders of eastward currents can be related to the effect of the meridional shear of the current.