A barotropic simulation of semi-diurnal and diurnal tides for the Monterey Bay region

Abstract

A barotropic tidal model is developed for the Monterey Bay (MOB) region, based on the multi-block grid code but using only a single-block grid. The model has realistic bathymetry with high resolution of 2 km x 2 km and covers a domain of 160 km x 160 km. The model is forced on the boundaries by four semi-diurnal (M2,S2,N2,K2) and four diurnal (K1,O1,P1,Q1) tidal constituents. The model study covers the one-month period of June 1996, and comparisons are made between the model output water levels and the tide gauge station data from Monterey, Moss Landing, and Santa Cruz. The model is used to study barotropic tides and their sensitivity to various open boundary conditions (OBC). Two common OBC, the clamped and the Reid and Bodine (RB) conditions, and a modified RB OBC are used to study barotropic tides. It is found that the barotropic model tide in the MOB region is very sensitive to the OBC. The two commonly used OBC reproduce the surface elevation reasonably well, but do not filter out long wave energy from the interior of the model domain for the MOB region. They may work well for shallow water applications, but changes are required for regions with steep bathymetry. For the MOB region the modified OBC developed in this study gives better results than the two commonly used OBC.