Coastal Storm Modeling System of California: CoSMoS Phase II

Coastal Storm Modeling System (CoSMoS) V 3.0 Phase 2

The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) of storm-induced coastal flooding, erosion and cliff failures over large geographic scales (100s of kilometers). CoSMoS was developed for hindcast studies, operational applications (nowcasts and multiday forecasts) and future climate scenarios (sea-level rise and storms) to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings.

Although the modeling system was initially developed for use in the high wave-energy environment of the U.S. west coast, CoSMoS is not site-specific and can be utilized on sandy and/or cliff-backed coasts throughout the world. The prototype system developed for the California coast uses the global WAVEWATCH III wave model, the TOPEX/Poseidon satellite altimetry-based global tide model, and atmospheric forcing data from either the U.S. National Weather Service (operational mode) or Global Climate Models (future climate mode) to determine regional wave and water-level boundary conditions, which are dynamically downscaled using a series of nested Delft3D wave (SWAN) and tide (FLOW) models. These data are ultimately linked at the coast to tightly spaced XBeach (eXtreme Beach) cross-shore profile models and a Bayesian probabilistic cliff failure model.