Influence of Domain Size and Grid Structure on the Response Characteristics of aHurricane Storm Surge Model

摘要

Formulation of a numerical storm surge model directly affects the physicalcontent of the predicted storm surge response. The influence of domain size and grid structure on computations of storm surge generation in the coastal region are studied. Storm surge response along the Florida shelf in the Gulf of Mexico due to Hurricane Kate is examined over three domains using two different open ocean boundary forcing functions. The computed storm surge response indicates that a small domain situated primarily on the continental shelf is inadequate since cross shelf boundaries are in regions of significant storm surge generation where surge and therefore boundary conditions are not known a priori. A second domain including the entire Gulf of Mexico basin captures the primary storm surge well but may not correctly model resonant modes. The dependence of these modes on interactions with contiguous basins makes accurate setup by the boundary condition specification difficult. The primary storm surge response as well as resonant modes excited by the storm are best represented using the largest domain, which encompasses the western North Atlantic ocean, the Caribbean Sea, and the Gulf of Mexico. This domain with deep Atlantic ocean boundaries facilitates simple boundary condition specification and minimizes the influence of boundary conditions on storm surge generation in the coastal region. Basin resonant modes and basin interactions are also captured.