The Generation of Internal Tides in the Strait of Sicily
and Adjacent Areas

Jihène Abdennadher and Moncef Boukthir

Institut Préparatoire aux Etudes d’Ingénieur de Tunis, Tunisia


The Regional Ocean Modelling System (ROMS) is applied to the problem of the generation, propagation, dissipation of internal tides and associated mixing in the Strait of Sicily and adjacent areas. A comparison with tide-gauge data, satellite data, and currentmeter measurements gave a good agreement.

M2 internal tides are effectively generated over prominent topographic features such as the NW of Sicily, Adventure Bank and the Strait of Messina. All of these topographic features are characterized by steep slopes. The M2 internal tides propagating away from these multiple source regions interfere with each other to create a complicate wave pattern.

The Adventure Bank is identified as the main area of generation of K1 internal tide. In fact, the major axes of the strong barotropic tidal current are directed across the isobaths of the western edge of the Adventure Bank which is very sharp. This may generates a significant internal tide which is coherent with the internal energy conversion rate distribution. Nevertheless, the cross and along shelf of the internal flux energy suggest that this energy is topographically trapped which is coherent with the fact that the diurnal frequency is subinertial at the latitude of the Sicily Strait.

Our results suggest that the internal waves in the Adventure Bank are essentially diurnal which is coherent with the observations of Artale et al. (1989). In contrast, the semidiurnal internal signal dominates in the Messina Strait. The baroclinic energy extracted from the tide is expected to make a significant contribution to mixing in the region.