INTERNAL WAVES IN A STRATIFIED SHEAR-FLOW - THE STRAIT OF GIBRALTAR

The wavelengths, directions, and phase speeds of internal waves propagating through the Strait of Gibraltar were measured from shore-based marine radar images of their surface features. Shipborne echo sounder images identified these waves as first mode and enabled their amplitudes to be measured. The moving features in the radar images were closely correlated with the waves in the echo sounder image. A numerical solution of the Taylor-Goldstein equation was used to predict the phase speed of the waves, utilizing simultaneous measurements of the density and velocity structure of the water column. Within the bounds of experimental error; there was good agreement between the theoretical and measured phase speeds of the waves on two different tidal cycles. No correlation appeared to be present between amplitude and estimated wave width, indicating that the waves were not behaving as Korteweg-deVries-type solitons.