Role of Hurricane Wind Models in Accurate Simulation of Storm Surge and Waves

Abstract

Storm-surge and wave models are routinely used to assess the impact of hurricanes/cyclones for emergency preparedness. Although these models are forced by wind fields, generated by meteorological models in hindcast or forecast mode, selecting a wind model that can accurately resolve the wind field, especially near the hurricane/cyclone core, is a challenging task. This study used several wind hindcast models to force a coupled wave and storm-surge model for selected hurricanes, including Bob (1991), Irene (2011), and Sandy (2012). The resulting simulated storm-surge and wave parameters were compared with observations at a number of observational stations. The wind models include the European Center for Medium-Range Weather Forecasts (ECMWF), the Northeast Coastal Ocean Forecasting System (NECOFS) based on the Weather Research and Forecasting (WRF) model, and parametric wind based on National Hurricane Center (NHC) data sets. The results show that a wind model that has an error in prediction of peak wind speed of more than 20% (when compared with observations) can lead to significant errors in hydrodynamic simulations; using a poor wind model can result in errors as high as 50% for storm-surge and wave predictions. Further, although no single best wind model for all hindcast applications can be recommended (for every region), a wind model that can simulate the environmental wind field and the internal structure of a hurricane (e.g., NECOFS in this study) can better address this uncertainty compared with conventional parametric wind models. The location of a hurricane track relative to the region of interest is a key factor in selecting the proper wind model.