On Recirculation Forced by an Unstable Jet

Abstract

Previous numerical experiments with an unstable zonal jet on a ? plane are extended to the reduced-gravity case. The strength of the resulting recirculation varies inversely with the combination ? + 1/S where S is the Burger number and ? the latitudinal variation of the Coriolis parameter. In addition, the centers of the antisymmetrically located gyres are located a distance from the jet inlet that varies inversely with the linear growth rate of small perturbations. An improved analytic model has also been constructed that predicts the recirculation strength and has the single unsupported assumption that the meridionally integrated potential vorticity anomaly be independent of zonal position.