Internal Waves in Strait of Gibraltar and Mediterranean Sea36.1N 5.3W
The waters of the Strait of Gibraltar (left) and the Mediterranean Sea (right) show a rippled pattern of internal waves. These are gravity waves that oscillate within, rather than on the surface of, a fluid medium. They arise from perturbations to hydrostatic equilibrium, where balance is maintained between the force of gravity and the buoyant restoring force.
A few ships can be seen passing through the strait separating Spain (above) and Morocco (below). However, the greatest number of vessels is concentrated around the self-governing British overseas territory of Gibraltar, located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean.
This image has been orthorectified so that the land around the strait can be observed free of geometric distortion.