Stationary Barotropic Modons in Westerly Background Flows

Abstract

An extension is given of the class of barotropic modon solutions on a sphere. In contrast to the previously obtained modons, the new solutions can be stationary in a solid-body rotation which is westerly. This property, as well as the fact that they are much less local than the earlier modons, brings them close to the Rossby-Haurwitz waves. Two examples are worked out to illustrate this resemblance and to give an impression of the new solutions. These examples also show that, for a limited region of the sphere, quite realistic flow configurationscan be obtained by a suitable choice of parameters. A numerical linear stability analysis has been applied to shed some light on the stability properties of the new solutions.