Experiments with baroclinic vortex pairs in a rotating fluid

Abstract

When vortices are generated in one layer of a rotating, two-layer density stratification, the velocity field of each vortex is strongly baroclinic within a distance of order one Rossby radius from its centre. In this system there are two classes of vortex pairs: those pairs (consisting of vortices of opposite signs) for which the vortices are in the same layer, and those for which the vortices are in opposite layers. We pay particular attention to a laboratory demonstration of the properties of the latter class. These vortex pairs have the ability to transport density (or heat) in the horizontal, and provide a means for describing the release of potential energy by baroclinic instability. We also observe that interactions of real vortices and real vortex pairs differ from those computed for point vortices.