Coupling a Parametric Wave Solver into a Hydrodynamic Circulation Model to Improve Efficiency of Nested Estuarine Storm Surge Predictions

Abstract

Efficiency in storm surge modeling is crucial for forecasting coastal hazards in real-time. While computation cost may not be the main concern for organizations with ample resources, the robustness of forecasts generated by most parties are restricted by wall-clock time. The Parametric Wave Solver (PARAM) was developed by Boyd and Weaver (2021) as an alternative to computationally expensive wind–wave models when modeling restricted estuarine environments. For this study, PARAM has been tightly coupled with the ADCIRC hydrodynamic model to create ADCparam, then integrated into the Multistage mini-ensemble modeling system (MMEMS), a one-way nesting framework for modeling waves and circulation in coastal estuaries developed by Taeb and Weaver (2019). In the MMEMS framework, ADCIRC + SWAN is used to simulate the coarser ocean domain and ADCparam is applied to the nested high resolution estuarine mesh. ADCparam has greatly reduced computation time for the high resolution nested sub-model compared to the third-generation wave model originally used. While the PARAM wave solution shows dissimilarities with the SWAN solution, significant wave height and wave period results are consistent and warrant further pursuit of the parametric wave ensemble method as a substitute to SWAN within MMEMS. ADCparam models demonstrated run times up to 51% faster than ADCIRC coupled with SWAN, an established iterative wave model tightly coupled to ADCIRC and packaged with the MMEMS repository. ADCparam wall time is comparable to running ADCIRC without wave forcing, nearly eliminating the computational cost of including the wave forcing in the high-resolution estuarine domain of MMEMS. Computational efficiency is greatly increased while maintaining solution integrity. Though ADCparam, and its application to MMEMS, are still being refined and validated, the coupled model system has proven to be an efficient, viable path for implementing waves in any estuarine circulation model.