Abstract
In a two-layer quasi-geostrophic model, the evolution of a symmetric baroclinic multipole, composed of a central vortex with strength μκ in the upper layer, and A satellites with strength κ in the lower layer, is studied. This multipole is imbedded in a center-symmetric shear/strain field, either steady or time-periodic. Special attention is given to the case of the tripole (A = 2). The stability of this tripole is assessed and its oscillations in the external field are analyzed. Conditions for resonance of these oscillations are derived and transition to chaos is described.
Acknowledgements
This study was carried out under GDRE “Regular and Chaotic Hydrodynamics” and supported by RFBR projects 10-05-00432-a, 10-05-00646-a, 09-01-92504/RUM1-2943-R0-09 from RFBR/CRDF, and by the Program “The development of the scientific potential of higher school” No. 2.1.1/554. Part of the study was carried out by MAS during his visit to LPO of UBO (Brest, France) in June–July 2008.
Notes
†Both types of critical points are known to be present, in particular, in stationary planetary waves, e.g. Hartman (Citation1977).
†The notion of “flip-over” between different motion regimes was first introduced by Gluhovsky and Klyatskin (Citation1977); see also Klyatskin Citation2008.
†As far as we know, Zaslavsky (Citation2007) was the first to discuss the effect of “adhesion” or “stickiness” of islands.