Browsing by Author "Dr. Lian Xie, Chair"

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    A numerical modeling study of the hydrodynamics of the Croatan-Albemarle-Pamlico Estuary System, North Carolina
    (2002-04-03) Peng, Machuan; Dr. Lian Xie, Chair; Dr. Frederick Bingham, Co-Chair; Dr. Leonard J. Pietrafesa, Member; Dr. David Eggleston, Member
    Numerical studies in the Croatan-Albemarle-Pamlico Estuary System (CAPES),are urgently needed for water quality control, environment protection and disastermitigation. In this study, a three-dimensional primitive equation hydrostatic model withhigh horizontal resolution is configured for the CAPES and its adjacent shelf toinvestigate barotropic/baroclinic wind driven circulation and sea level changes, riverdischarge induced flow, barotropic M2 tide, tidal current and tide-residual current. A newinundation/drying scheme is developed to allow the water-land boundary in the model tomove for simulating hurricane-induced coastal flooding and drying. This inundationalgorithm is based on the sea surface height relative to the adjacent topography, as well asthe distance traveled by the coastal interface, which is determined by the current speedimmediately seaward of the sea-land boundary.The main conclusions of this study are summarized below: (1) The verticalstructure of the wind driven circulation is more complicated in the coastal regions than inthe open area. On the open sea it follows a frictional Ekman equilibrium. (2) Thebaroclinic wind-driven current in the CAPES is over 40 cm/s in some regions due to greatvariations of the salinity distribution. (3) Stream flow nudging is a better method forspecifying the flux boundary condition near a river mouth than the barotropic-flowmethod in simulating river discharge induced flow. In annual mean case, such flow canbe ignored for its contribution to the coastal circulation, however, it could not be ignoredin flood cases. (4) M2 tide is much higher near the coast than inside the CAPES, but M2tidal currents in some regions inside Pamlico Sound can be greater than outside. Therelatively small M2 tide-induced residual current is stable and may have potential effectson long-term cross shelf transport. (5) Mass conservation must be considered in a closedor near closed estuary region when the inundation process is studied, and surface ratherthan vertically averaged current speed should be taken as the inundation speed.