Comparison of finite difference and element models of internal tides on the Malin–Hebrides shelf

A three-dimensional baroclinic finite element model with a coarse and fine (i.e. local refinement along the shelf edge) grid is used to examine the influence of shelf edge grid refinement upon the internal tide generation and propagation off the west coast of Scotland. Comparisons are made with observations in the region and with a published solution using a finite difference model. The calculations show that provided that the finite element grid is refined in the internal tide generation area and the adjacent region through which the internal tide propagates, then a numerically accurate solution is obtained. In the regions of strong internal tide generation with a local grid refinement, internal wave energy can accumulate at small scales and must be removed by a scale-selective filter.