Optimization of Unstructured Grids for Coastal Ocean Hydrodynamical Models

The development of unstructured triangular meshes used for the simulation of coastal ocean hydrodynamics is studied. For these meshes, we quantify the variability in the simulation of barotropic water levels associated with mesh design choices. We demonstrate that the placement of mesh resolution alters the fidelity of geometric-bathymetric features in the coastal ocean, which lead to convergent patterns in the simulation of the local and regional coastal ocean circulations. An automatic and self-consistent mesh generation workflow is presented that enables us to carefully constrain the placement of mesh resolution along geometric-bathymetric features. From an initial high-resolution mesh of the East Coast Gulf Coast (ECGC) region, we perturb a series of mesh size functions that control the resolution resolves bathymetric features and shoreline geometry. Results indicate that by altering mesh resolution along the continental shelf margins coherently alters the phase and co-tidal structure of the semi-diurnal species in basins like the Gulf of Maine and the Gulf of Mexico. We find that the minimum mesh size selection leads to a simplification of the shoreline that creates pronounced variations in the resonant patterns of semi-diurnal tides inside large-estuaries along the Eastern coast of the United States.