Comparison of Two- and Three-Dimensional Model Simulation of the Effect of a Tidal Barrier on the Gulf of Maine Tides

Abstract

Two-dimensional and three-dimensional tide models were used to simulate 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 by Greenberg and by Duff. The three-dimensional model uniformly produced 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 compared. Root-mean-square errors of M2 tidal amplitude and phase at 45 locations in the Gulf of Maine were 7.9 cm and 6° for the two-dimensional model and 5.7 cm and 7° for the three-dimensional model. Both models predicted essentially identical frictional dissipations for the Gulf of Maine of 4.8–4.9×1010 watts. Spatial differences in dissipation did not alter model predictions of well-mixed regions in the gulf based on a vertical mixing parameter used by Garrett et al. for the same region.