Internal Tide Energetics in the Sicilian Strait

A non-linear hydrostatic model (ROMS) is used to study the generation and propagation of internal tides in the Strait of Sicily. Realistic topography and stratification from existing observational data were used. The numerical simulations has shown that there are three distinct sites of strong M2 internal tide generation: the western sill of the Adventure Bank, northwest of Sicily, and north of Pantelleria island. The conversion from the M2 surface to internal tide energy integrated over the whole model domain amounts to 47.5 MW, 75% of which are found to be generated over the three prominent topographic features mentioned above. The depth-integrated baroclinic energy flux of the M2 internal tide shows two directions of propagation (north and southwest) at the western sill, the most energetic site. About 42.3 % of the M2 baroclinic energy produced in the modelled region is dissipated near the generation sites.

The K1 internal tide is generated mainly at the Adventure Bank’s edge and near the Pantelleria island. The conversion of energy from surface to K1 internal tide in the strait of Sicily is approximately 30 MW. This energy is completely dissipated at the strait. This is because the K1 frequency is sub-inertial at this latitude and cannot propagate. Analysis of the internal flux reveals that the K1 internal tide is topographically trapped which is consistent with Artale et al. (1989).