COMPARISON OF 2-DIMENSIONAL AND 3-DIMENSIONAL MODEL SIMULATION OF THEEFFECT OF A TIDAL BARRIER ON THE GULF OF MAINE TIDES

Two-dimensional and three-dimensional tide models were used to simulat e the M2 tide in the Gulf of Maine. Model estimates of changes to the tide caused by a tidal barrier in the upper Bay of Fundy were made and compared. Tidal amplitudes in the presence of a barrier increased 30- 50 cm for both models, corroborating the results of previous studies b y Greenberg and by Duff. The three-dimensional model uniformly produce d postbarrier elevations of 3.5 cm less than the two-dimensional model in the Gulf of Maine. A comparison of model amplitudes and velocities with data for the existing M2 tide is provided for both models. Total frictional dissipation is also calculated for each model and compared . Finally, the postbarrier amplitudes as predicted by each model are c ompared. Root-mean-square errors of M2 tidal amplitude and phase at 45 locations in the Gulf of Maine were 7.9 cm and 6-degrees for the two- dimensional model and 5.7 cm and 7-degrees for the three-dimensional m odel. Both models predicted essentially identical frictional dissipati ons for the Gulf of Maine of 4.8-4.9 X 10(10) watts. Spatial differenc es in dissipation did not alter model predictions of well-mixed region s in the gulf based on a vertical mixing parameter used by Garrett et al. for the same region.