Book Description

A two-dimensional time dependent numerical storm surge model employing orthogonal curvilinear coordinates is presented. The curvilinear coordinate system results from the conformal mapping of the interior region bounded by the actual coast, the seaward boundary (taken as the 100-fathom depth contour) and two parallel lateral boundaries into a rectangle in the image plane. Three regions of the continental shelf of the Gulf of Mexico and two regions of the eastern seaboard of the United States are mapped. Since the transformation is conformal, the associated modifications of the vertically integrated equations of motion and mass continuity are minimized. The coast, seaward boundary and the lateral boundaries of the computing grid are straight lines in the image plane thus facilitating the application of the boundary conditions. Moreover, the injection of spurious oscillations into the calculations is abated with the coast represented as a straight line. The final coordinates allow for the greatest resolution near the coast in a central area of principle storm surge development and modification. A second transformation is performed independently on each of the curvilinear coordinated to ensure that the finite difference analogs of the spatial derivatives are centered. The model is employed in the simulation of the storm surge induced by Hurricane Carla (1961) and Camille (1969) which crossed the Gulf Coast of the United States and Hurricane Gracie (1959) which crossed the East Coast. Analytical interpretations of the wind and atmospheric pressure forcing functions are utilized in the computations.