Florent Lyard (Université de Toulouse, LEGOS (CNES/CNRS/IRD/UT3), France); Michel Tchilibou (CLS, France); Patrick Marsaleix (Université de Toulouse, LEGOS (CNES/CNRS/IRD/UT3), France); Marine Herrmann (Université de Toulouse, LEGOS (CNES/CNRS/IRD/UT3), France)

The internal tides are generated when the barotropic tides pass through a steep slope, perturbing the stratification of the ocean. With complex bathymetry, deep semi-closed seas, shallow straits, and a strong spring-neap tide cycle due to similar diurnal and semi-diurnal tides, the Indonesian seas are the realm of internal tides. The specific shape of the straits also leads to a rapid degeneration of the internal tides into internal solitary waves (Qiu et al., 2024). The numerous sites of generation around the same sea result, for the surface elevation, in a complex pattern mixing a wide range of wavelengths and directions. In the scope of TOSCA-SCOEPUS project, we aim to distinguish the internal solitary waves from the internal tides in SWOT observations.
On one hand, the SWOT Unsmoothed observations are unprecedented in characterizing the internal solitary waves, e.g. sampling down to 1 km wavelengths in places where these waves are the most energetic. On the other hand, the time sampling and the duration of the time series can only provide information on the internal tides through harmonic analysis (ITkar method; Tchilibou et al., 2025) during the CalVal phase. In contrast, numerical modeling (SEA simulation; Garinet et al., 2024) cannot resolve the internal solitary waves but is used to characterize the theoretical regime of internal tides. To compare both approaches, new high-resolution bathymetry and coastlines have been used in the model to improve the tidal circulation and match most of the generation sites. The combined approach leads to the quantification of the internal tides dissipation that the numerical models lack and could be used to validate the wave-wave and wave-circulation interactions simulated.