Semi-diurnal internal wave diffraction caused by Dixon Entrance, British Columbia

To develop an understanding of the complex internal tidal phenomena observed near and inside Dixon Entrance, an idealized numerical model was developed for the area, which explores the influence of various topographic features on the scattering of internal tides. The model uses a non-linear, two-layered, frictionless finite difference formulation of the shallow water equations and is forced by a barotropic wave over simplified topography. It was found that the main bathymetric features responsible for the generation of semi-diurnal internal tides are the steep continental slope together with the orientation of Dixon Entrance. The prevalent baroclinic wave pattern, which is similar to the one found by Buchwald (1971), suggests that the western end of Dixon Entrance can be considered as an internal tide generation region for the open ocean. Use of the simple model allows easy identification of the generated waves. When the model is run with a non-flat channel it reproduces features observed inside Dixon Entrance.