Influence des ondes d'inertie-gravité sur la dynamique tourbillonnaire

The purpose of this thesis is to study the influence of inertia-gravity waves on eddies dynamics, this process being part of the interaction between slow and fast dynamics of oceanic flows. Eddies dynamics is indeed slow but it is also intermediate between the fast inertia-gravity waves dynamics and the very low frequency dynamics of general circulation. The first part reviews the literature on this interaction. Then two numerical studies are performed. The first one concerns the influence of inertia-gravity waves on the filamentation diagnostic of an elliptic vortex. In presence of inertia-gravity waves this filamentation process is found to be slightly altered. However, the information required to analyze the filamentation process is shown to be entirely captured by the slow component of the flow and regions of filament ejection can be identified from the diagnostic criterion of Lapeyre et al. (1999) based on instantaneous slow quantities. The second numerical study shows that inertia-gravity waves alter eddies interaction. For that purpose, the tripolar vortex is used as an academic example of an eddies interaction. The core of such a structure may split if the two satellites are strong enough. For all cases of waves that have been tested, the structure is systematically stabilized : the core breaks down more easily without inertia-gravity waves than in their presence.