A 3-DIMENSIONAL MODEL OF THE M2, S-2,N-2,K-1 AND O-1 TIDES IN THE CELTIC AND IRISH SEAS

A three dimensional model using various parameterizations of eddy viscosity, covering the Celtic and Irish Sea region, is used to examine the spatial distributions of the M2, S2, N2, K1 and O1 tidal elevations and phases. Computed cotidal charts and comparisons with observations from shore based and offshore gauges show good agreement. Comparisons are also made with a standard two dimensional model. In shallow water regions the three dimensional model shows significantly less damping than the two dimensional model with an associated improvement in accuracy. A detailed examination of differences between computed and observed tidal currents, at over thirty locations having three or more current meters in the vertical, show that the model can accurately reproduce the tidal current and its vertical profile. In the eastern Irish Sea, the region furthest from the model's open boundary, good agreement with observations is obtained, although in the deeper channel to the south of this, the model over-predicts current magnitude.