Noé Lahaye (Inria, france)

One of the new and relatively unexpected features appearing in SWOT sea level observations are internal solitary waves (ISW). This study reports on the Maluku Sea where ISW were systematically observed during SWOT fast sampling phase, with typical sea level anomaly of 20 cm and spatial extent of the front of a few kilometers. We systematically describe the occurrence of these waves and its relationship with the phase of the tidal cycle, the geometrical shape of the wave packets, its propagation speed, as well as the shape of each individual wave. These observations are compared against analytical and numerical predictions from simplified ISW dynamical models (KdV style). Using semi-analytical solutions of ISW trains to fit the observations, we show that one can extract quantitative information on the amplitude and shape of the ISW train, and extrapolate its structure at depth (deviation of isopycnals and currents). These results support the high potential of SWOT data in providing unprecedented measures of ocean dynamics at the submesoscale.