2018 Volume 74 Issue 1 Pages 92-106
This paper describes the applicability of a numerical ecosystem model that was developed by the authors on the basis of the finite volume community ocean model, i.e., FVCOM. We summarize the inhibition effects of oyster reef on the hypoxic water formation in Ariake Sea, Japan, which was investigated by using the developed ecosystem model. The results showed that oyster reef decreased the concentration of phyto-plankton and particulate organic carbon through its filtration activity, and increased the dissolved oxygen (DO) concentration in the bottom layer over a wide area. In addition, we explain an appropriate discretization method for decreasing the pressure gradient force (PGF) errors associated with the application of the terrain-following (σ) coordinate system to estuarine modeling based on FVCOM. The validations of the standard second-order scheme and the z-levels scheme for the PGF errors, were made under the conditions of horizontally-uniform stratification without external forcing, and a realistic stratification with external forcing. The comparison of the numerical results with field observations showed that the z-level scheme can greatly improve the accuracy of the numerical simulation, suggesting the importance of using the appropriate scheme for the PGF errors even in the estuarine modeling with high grid resolution.
