The Structure of the Internal Tide at the Celtic Sea Shelf Break

Abstract

Measurements at sea in the Biscay and Celtic Sea have shown that the peak to trough displacement of the internal tide maximises at the shelf break of the Celtic Sea with peak to trough values in excess of 50 m at spring tides during the summer. In this region the internal tide generated at the top of the slopes is highly distorted by the shelf barotropic tidal currents. The internal tide propagates on-shelf towards the coast and off-slope towards the ocean as a decaying progressive wave. A simple model is developed that illustrates many of the observed features of the measured structure of the internal tide.