Titre/Title : Eddies in Wakes of Islands and Deep Sea Mountains
Contact : Joel Sommeria (équipe MEIGE)
Résumé/Abstract : When a flow passes an obstacle in a rotating and stratified fluid, the wake evolution is different from that in a classified homogenous and non-rotating fluid. The talk includes two parts : wakes of islands and deep-sea mountains. We apply data from satellite remote sensing, in-situ measurement, numerical modeling and laboratory experiments on a rotating tank to the study. For the island case, when the wind blows over an island, the wind is weaker behind the island, resulting in weaker mixing and warm SST and also induces positive and negative wind curls. In response to wind curls, oceanic eddies could be generated. When an oceanic flow passes a deep or shallow island, the generation and evolution of vortex in the wake are different. For the deep sea mountain case, due to the inhomogeneity in the bottom friction, the front in the bottom boundary layer is presented, which results in a jet along the front. The instability of the jet could results in eddy generation in the wake. Two deep sea mountains in northwestern Pacific Ocean are investigated using observational data and high-resolution numerical modeling.