Abstract

WW3 is a major spectral wave modeling system known for its applicability in large-scale modeling of sea states and wave climate from large rectilinear grids offshore to high-resolution unstructured grids in coastal zones, being widely used in operational, research and engineering arenas. Over the past few years, the operational global system at NCEP utilizes the multi-grid capabilities, where various rectilinear grids are nested internally to represent the offshore domain with a less computationally expensive coarse grid while the nearshore is run at a high-resolution grids. Alternatively, a single unstructured grid can be used for such applications. Recent advances in the performance of the model on unstructured grids provide the opportunity to run the model on large unstructured grids efficnetly. Here, an assessment of the operational global setup and unstructured wave models on various resolutions are given. The sensitivity to global unstructured mesh design was investigated using triangular meshes with a global minimum element size that ranged from 1.5 km to 6 km with local mesh refinement in storm landfall location. The validation is performed against satellite altimeter data and offshore NDBC network during normal and stormy conditions. We demonstrate that an optimized unstructured WW3 can be used for global applications, with superior performance relative to the complicated multi-grid system.