Assimilating TOPEX/POSEIDON derived tides in a primitive equation model over the Newfoundland Shelf

M2 semidiurnal tidal elevations and currents over the Newfoundland Shelf are derived by combining tidal analyses of TOPEX/POSEIDON altimeter data and a regional hydrodynamic model in an Assimilation scheme based on optimal linear interpolation. The model is governed by three-dimensional nonlinear primitive equations for homogeneous fluids and a turbulence closure scheme for vertical eddy viscosity. The results are compared with a complementary Baseline model forced by boundary conditions derived from earlier work, independent of the altimetrically derived tides. In situ sea level and current measurements provide a second independent check of the Assimilation model results. Tidal heights from the Assimilation model agree with both the Baseline model and the observations within the expected in situ errors. Useful results in a coastal setting were thus achieved with TOPEX/POSEIDON derived tides as the only external input. A comparison of model and observed current fields shows greater differences: the model flow fields are sensitive to differences in tidal elevation that are still at the noise level in presently available altimetric and in situ measurements.