Abstract: The process by which unstable jets shed vorticity is investigated numerically for Gaussian jets with a quasi-geostrophic model. The shedding process that occurs in jets evolved from potential-vorticity-conserving perturbations is compared with that from transport-conserving perturbations given in the literature. The differences in vorticity pool formation and meander pinch-off between the two situations are discussed for the barotropic jets on a β-plane. The concept of acceleration potential is applied to show that the jet instability and vorticity shedding occur through the feedback between the jet meander and vorticity flux convergence. The analysis is extended to two-layer baroclinic jets. It is shown that the vortex stretching produced by the isopycnal displacement stabilizes the jets as β does and that such an effect allows meander pinch-off. The mixed barotropic-baroclinic instability of the Gaussian jet is shown to occur as a result of the phase difference between the destabilizing vorticity flux convergence and the stabilizing vortex stretching.
Publication Year: 1994
Publication Date: 1994-12-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 3
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