The Effects of Flow Asymmetry on the Direction of Rossby Wave Breaking
The relationship between the direction of the breaking of Rossby waves on an isolated jet and the cross-jet asymmetry of the flow is investigated. The flow structure of a circular jet is, under most circumstances, such that waves break uniquely outward, although the authors contrive a flow on which breaking is uniquely inward. The influence on the direction of the breaking of the location of critical lines in the undisturbed flow is discussed. On a straight jet with asymmetric shear, there are three wave amplitude regimes: weak waves do not break; waves of moderate amplitude break only toward the closer critical line; and waves of sufficiently large amplitude break both ways.