Corpus Christi Bay Three-Dimensional Hydrodynamics and Salinity Simulations Using Finite-Volume Coastal Ocean Model (FVCOM)

Abstract

Corpus Christi Bay is a typical hypersaline coastal basin along the Texas coastline. An unstructured grid, three-dimensional, finite-volume coastal ocean model (FVCOM) was applied to simulate wind-, tidal-, and buoyancy-driven water level variation, current velocity fluctuation, and long-term salinity trend in the bay. A oneyear simulation has been carried out for the year 2000. Comparisons between observations and model simulation show that FVCOM is very accurate in simulating sea level oscillations. The average correlation coefficient and Index of Agreement are 0.96 and 0.97, respectively, for sea level elevation. The velocity simulation is visually consistent with available ADCP measurements. However, no quantitative assessment can be done due to the short duration and non-uniform interval of the observed time series. The salinity simulation is not as satisfactory as that of sea level and current velocity. Possible reasons for this discrepancy are discussed. Further analysis of model results shows that the tidal circulation in the Corpus Christi Bay-Aransas Pass system is consistent with the existing picture of tidal inlet dynamics. The sea level variation in the bay is mostly a spatially-uniform pumping mode response to oscillations at the ocean side. The tidal residual current pattern at the entrance of the tidal inlet consists of a jet and two counter-rotating eddies. The sub-tidal wind-driven circulation in the Corpus Christi Bay is consistent with Csanady’s classic theory in that wind induced flows tend to be downwind in shallow water while they are upwind in deep water.