Gerald Dibarboure (CNES, France); Fabrice Ardhuin (CNRS/LOPS, France); Lucile Gaultier (ODL, France); Yannice Faugere (CLS, France)

In the next decade, new spaceborne instruments should revolutionize the observation of Ocean surface dynamics at fine scales. SWOT and follos-up missions will bring high-resolution measurements of the surface dynamic topography, and Doppler current mission (such as SKIM or WaCM) may fly in orbit to provide direct total surface current observations.
The synergy of dynamic topography and surface current is obviously very promising as many dynamic processes share signatures on one or both variables, but this may be challenging.
This study investigates, from Observing System Simulation Experiments, the potentials for reconstructing the surface current using various mapping approaches combining Sea Surface Height and total surface current. It first suggests the problem is not trivial. Indeed, the high-frequency signals of fine-scale altimetry (e.g. internal waves) and surface current (e.g. inertial oscillations) are important, but under-sampled in time potentially leading to strong aliasing in the estimates.
After showing that basic mapping approaches processing altimetry and total current separately would fail, we will show that specific inversion schemes accounting for oscillating covariances can be very efficient in compensating for the moderate observation revisits of the high-frequency processes.
Even to reconstruct the total current with direct observations of the same variable, the altimetry revealed still essential to constrain the degrees of freedom in the inversion, through accurate separation of balanced and unbalanced dynamics.