Modeling hydrodynamics of the Mississippi Sound and adjoining rivers, bays and shelf waters

A regional scale modeling system is being developed for the Mississippi Sound and adjoining Mobile Bay, Biloxi Bay, Bay St. Louis, and Lake Borgne. The modeling system, consisting of a three-dimensional circulation model, a cohesive and non-cohesive sediment transport model and a wave model, will provide a reliable means to forecast littoral circulation, sediment suspension and transport, and surface waves. The modeling framework adopts a high-resolution orthogonal curvilinear grid that adequately resolves the bathymetric and coastline features of the Sound, especially the region of the barrier islands. The southern model boundary follows the 200-m isobath, a natural dynamical barrier between the Sound and the rest of the Gulf of Mexico. The model performance has been evaluated to date by conducting tidal simulations using boundary conditions derived from a global tidal model and then compared with tides at the IHO stations across the Mississippi Sound. Freshwater plume dynamics emanating from various estuarine systems dynamically connected to the Sound have also been evaluated using the current model. Future model improvements will involve novel open boundary condition schemes and wave-induced physical processes. A comprehensive model calibration/validation effort will then follow.