Towards the simultaneous dynamical mapping of balanced motions and internal tides from SWOT

– Florian Le Guillou – Doctorant IGE/CLS, Grenoble

Résumé: The Surface Water and Ocean Topography (SWOT) mission is expected to provide Sea Surface Height (SSH) measurements resolving scales of a few tens of kilometers. Over a large fraction of the globe, the SSH signal at these scales is essentially a superposition of a component due to balanced motions (BMs) and another component due to internal tides (ITs). Several oceanographic applications require the separation of these components and their mapping on two-dimensional regular grids. For that purpose, we introduce a variational method along with two reduced dynamical models, each specific to the mapping of one component: a quasi-geostrophic model for BMs, and a linear shallow-water model for ITs. A particular effort is made to perform the inversions in well-chosen reduced-order basis. The algorithm is tested with Observation System Simulation Experiments (OSSE), where the true state of the ocean is provided by the MITgcm global LLC4320 simulation. We focus on a realistic observational scenario in the California Current System during the SWOT’s fast sampling phase. The proposed algorithm is able to map and separate a large amount of the variance of BMs and ITs. Importantly, in addition to the reconstruction of stationary ITs, the algorithm estimates the amplitude and phase of nonstationary ITs, which is very encouraging for the process of future SWOT data.

Lien Zoom: https://univ-tlse3-fr.zoom.us/j/97230511694?pwd=V2xNdXFQNEtsWTA4dlFVVm5GMUFIQT09

ID de réunion : 972 3051 1694
Code secret : 342988