Ocean Science Directorate

Two-dimensional numerical models were used to further study appropiiate conditions at the open boundaries for regional models forced by parameters from a global tidal model. The open boundary condition of Reid and Bodine (1968) was applied to regional models of the western Florida shelf, north-central Gulf of Mexico, and the Kenya Coast. In addition, two semienclosed basins were modeled, the Persian Gulf, and the entire Gulf of Mexico. A number of tests were conducted to determine how well forcing, using the tidal constants from the 10xl ° Schwiderski global model (1981, 1983) could reproduce regional tides as determined from observations. As seen in our previous work, the Reid and Bodine formulation was quite effective in driving the regional models while still allowing wave energy to propagate through the open boundaries and out of the model. The western Florida shelf is known to resonate with the M2 tide. Under such circumstances, the bottom friction becomes quite important in obtaining correct predictions of the observed tidal amplitudes. Several bottom friction schemes with varying drag coefficients were tested for both the north-central gulf and Florida shelf models. The results are discusse