Strong Internal Tides in the Strait of Gibraltar: Measurements and Modelling

We analyze moored current measurements in the Strait of Gibraltar. Internal waves are extremely strong in the strait. The vertical displacements of water particles with a semidiurnal frequency sometimes exceed 200 m. These displacements are associated with forced tidal internal waves over the Camarinal Sill, which crosses the strait. The amplitudes of the waves decrease with the distance from the sill, and at a distance of 50 km from the sill, the amplitudes are three times smaller than over the sill. Numerical modelling shows that the lower current in the strait directed from the Mediterranean Sea to the ocean has a significant influence on internal tides. The effect of internal waves propagating in a hydraulic flow leads to the formation of internal bore, followed by a wave packet of shorter internal waves.