Baroclinic tides at a North-West European margin: Analytical modelling compared to in situ data

In this paper, we present an analytical modelling of internal tide generation at steep continental margins. By extending the model devised by Rattray (1960), a simple model accounting for the stratification of the ocean (2-layer), the earth's rotation, free surface boundary conditions, radiation condition at the coast and the oblicity of the incident barotropic Poincare wave with respect to the shelf-break (modelled by a step) is derived. This model predicts that waves propagate along horizontal rays, which are refracted by bottom variations: basically, Snell laws are retrieved. Under the assumption of small density ratio and thin upper layer, amplitudes of both transmitted and reflected, baroclinic and barotropic waves are solution of a simplified linear system presented here. The present model is compared with in situ data measured at the Malin Shelf shelf-edge during a UK NERC LOIS/SES cruise in 1996.