A TIDAL MODEL FOR EASTERN JUAN-DE-FUCA STRAIT AND THE SOUTHERN STRAIT OF GEORGIA

A three-dimensional, barotropic, finite element model is used to calculate the tidal hows in eastern Juan de Fuca Strait and the southern Strait of Georgia. The harmonics of eight constituents are computed and compared with those from previous finite difference models and those from historical tide gauge and current meter observations. Root-mean-square differences between observed and calculated sea level amplitudes are within 2.0 cm for all constituents, and the phases are within 4.0 degrees for all constituents except K-2. Horizontal currents from the model are found to reproduce the observed vertical variations in shear except in regions where stratification effects and internal tides exist. In particular, the model representation of currents at six stations in the Canadian Tide and Current Tables (volume 5) is accurate. The pattern of tidal residual currents has much more detail than previous, coarser resolution models, and numerous eddies are predicted. Computed energy flux fields reveal that over a 29-day period only 38% of the tidal power entering Juan de Fuca Strait is transmitted into the southern Strait of Georgia, and of the 39% entering Hare Strait, 36% is dissipated within the strait itself.