The Influence of Wind Direction upon Flow along the West Coast of Britain and in the North Channel of the Irish Sea

Abstract

This paper briefly describes the development of a three-dimensional nonlinear hydrodynamic model of the sea region off the west coast of Scotland, the North Channel, and the Irish Sea. The model uses a sigma coordinate in the vertical, and subgrid-scale mixing of momentum is parameterized by a vertical eddy viscosity computed using a turbulence energy submodel. Numerical calculations illustrate the importance of wind direction and topography in determining flow pathways along the west coast of Scotland, through the North Channel, and within the Irish Sea. The role of a northward flow into the Irish Sea through St. George's Channel, arising from wind events over the Celtic Sea, in controlling the flow in the North Channel and deep regions of the Irish Sea is also considered. The series of calculations presented here helps to explain the spatial and temporal variability of the observed flows (from both direct measurements and tracer studies) found off the west cost of Scotland and in the North Channel and the Irish Sea.