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| Reinaud, Jean N.; Carton, Xavier. |
| We consider the interaction between two quasi-geostrophic vortices of height-to-width aspect ratio h/r, lying at two different vertical levels. We investigate whether such structures naturally align. In the case the vortices occupy distinct yet contiguous vertical levels, such an alignment can contribute to the growth in volume of oceanic mesoscale vortices. The other growth mechanism is the merger of vortices sharing common vertical levels. We show that there exist titled equilibrium states where vortices nearly align slantwise. Most equilibria for prolate vortices (h/r>1) are stable apart in a very narrow region of the parameter space. The instability is however normally non-destructive. Pairs of oblate vortices may also be in an unstable equilibria... |
| Tipo: Text |
Palavras-chave: Vortex dynamics; Vortex alignment; Quasi-geostrophy. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71259/69643.pdf |
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| Reinaud, Jean N.; Carton, Xavier; Dritschel, David G.. |
| We investigate the interaction between a heton and a current generated by a filament of buoyancy anomaly at the surface. Hetons are baroclinic dipoles consisting of a pair of vortices of opposite signs lying at different depths. Such structures have self-induced motion whenever the pair of vortices are offset horizontally. A surface buoyancy filament generates a shear flow since the density perturbation locally modifies the pressure field. The vertical shear induced by the filament offsets the vortices of the heton if vertically aligned initially. Moreover, if the vortex nearer the surface is in adverse horizontal shear with the buoyancy filament, the heton tends to move towards the filament. Conversely, if the upper vortex is in cooperative horizontal... |
| Tipo: Text |
Palavras-chave: Quasi-geostrophy; Surface buoyancy anomaly; Vortex dynamics. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00600/71253/69631.pdf |
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