Global storm tide modeling with ADCIRC v55: unstructured mesh design and performance

Abstract. This paper details and tests numerical improvements to the ADvanced CIRCulation (ADCIRC) model, a widely used finite-element method shallow-water equation solver, more accurately efficiently model global storm tides with seamless local mesh refinement in landfall locations. The sensitivity unstructured design was investigated using automatically generated triangular meshes minimum element size (MinEle) that ranged from 1.5 6 km. We demonstrate refining resolution based on topographic seabed gradients employing MinEle less than 3 km are important for accuracy of simulated astronomical tide. Our recommended (MinEle = km) these results locally refined down two separate values (500 150 m) at coastal locations intense storms (Hurricane Katrina Super Typhoon Haiyan) model's capability tide simulations test refinement. Simulated maximum elevations closely follow lower envelope observed high-water marks (HWMs) measured near coast. In general, peak along open coast decreased, timing occurs later However, this only has significant positive impact HWM errors straits inlets narrower bays lakes separated ocean by passages. Lastly, we computational performance new treatment is 1 2 orders magnitude faster studies previous ADCIRC versions because gravity-wave-based stability constraints removed, allowing larger time steps.