Meander Evolution on Piecewise-Uniform, Quasi-geostrophic Jets

Abstract

A variety of simple, two-layer representations of a quasi-geostrophic jet along a vorticity front are initialized with a simple meander. The subsequent evolution of the jet is followed and related to the observed behavior of the Gulf Stream front east of the New England sea mounts. By varying the horizontal and vertical structure of the jet, a range of behavior is obtained that includes shingle formation and eddy detachment. These effects can be related to the linear stability properties of the jet. The structure that exhibits the most realistic meander evolution is that of a jet associated with a simple baroclinic vorticity front separating two pools of vorticity in the upper layer and two weaker pools in the lower layer. This picture is consistent with what one can inter from the known density structure of the Gulf Stream in this region.