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 investi gated. The flow structure of a circular jet is, under most circumstanc es, such that waves break uniquely outward, although the authors contr ive a flow on which breaking is uniquely inward. The influence on the direction of the breaking of the location of critical lines in the und isturbed flow is discussed. On a straight jet with asymmetric shear, t here 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.