A high-resolution assimilating tidal model for the northeast Pacific Ocean

A high-resolution, nonlinear, barotropic. finite element tidal model is developed for removing tidal elevations from satellite altimeter observations in the northeast Pacific Ocean. Surface elevations and currents for the constitutents M-2, S-2, N-2, K-2, K-1, O-1, P-1, and Q(1) are computed using boundary forcing from the Oregon State University global tidal model, TPXO.3, and the effects of the tidal potential, Earth tide, and ocean self-attraction and loading. Amplitudes and phases computed from the harmonic analyses of altimeter time series at crossover locations along the tracks of the TOPEX/Poseidon satellite are assimilated into the model, and the corrected harmonics are compared with pelagic and coastal tide and pressure gauge measurements, and with the TPXO.3 and FES95.2.1 global models. Diurnal tidal currents along the British Columbia and Alaska continental shelves. are shown to be strongly influenced by the presence of continental shelf waves. The surface manifestation of these waves is clearly evident in K-1 coamplitude plots. K-1 and M-2 energy fluxes are calculated along these shelves and the potential generation of internal tides is discussed. Barotropic tidal dissipation is estimated in several key subregions, and the M-2 total for the Gulf of Alaska is found to be approximately half that of previous estimates.