Leveraging surface drifters tracks for the identification of high frequency signatures in future wide-swath altimetric data

Incoming wide-swath altimeters such as SWOT (launch date 2021) will provide pictures of sea surface elevation with unprecedented coverage and resolution. They will in particular improve our ability to measure scales between 10-100km. A challenge with this new picture will reside in the separation of high frequency motions (e.g. internal waves) from lower frequency geostrophically balanced ones. Thanks to their ability to temporally discriminate both types of motions, we advocate surface drifters may provide useful information in order to overcome this challenge. In idealized numerical simulations, this work quantifies the signature of low-mode internal tides on drifter track data in the presence of a background low-frequency turbulent flow. Lagrangian and Eulerian energies and phases are compared. We draw conclusions on the applicability of the drifter/altimetric combinaison for the separation of high and low frequency motions.