| Numerical studies in the Croatan-Albemarle-Pamlico Estuary System (CAPES), though advanced rapidly in the past decades, are urgently needed for accurate hydrodynamic prediction and for water quality control, environment protection and disaster mitigation. In this study, a three-dimensional primitive equation hydrostatic model with high horizontal resolution is configured for the CAPES and its adjacent shelf to investigate barotropic/baroclinic wind driven circulation and sea level changes, river discharge induced flow, barotropic M2 tide, tidal current and tide-residual current. A new inundation/drying scheme is developed to allow the water-land boundary in the model to move for simulating hurricane-induced coastal flooding and drying. This inundation algorithm is based not only on the sea surface height relative to the adjacent topography but also on the distance traveled by the coastal interface which is determined by the current speed immediately seaward of the sea-land boundary.; Main conclusions of this study are summarized below: (1) The three dimensional structure of the wind driven circulation is more complicated in the coastal regions than in the open area. On the continental shelf it follows the frictional Ekman equilibrium. (2) The baroclinic wind-driven current in the CAPES could reach over 40 cm/s in some region due to great variation of the salinity distribution. (3) Stream flow nudging is a better method to specify the flux boundary condition near a river mouth than barotropic-flow method in simulating river discharge induced flow. In normal years, such flow can be ignored for its contribution to the coastal circulation, however, it could not in flood cases. (4) Tide is much higher near the coast than inside the CAPES, but M2 tidal currents in some regions inside the CAPES can be greater than those on the shelf. The relatively small M 2 tide-induced residual current is stable and may have potential effects on long-term cross shelf transport. (5) Mass conservation must be considered in a closed or near closed estuary region when the inundation process is studied, and surface rather than vertically averaged current speed should be taken as the inundation speed. |
