Evaluation of WAVEWATCH III Wave Model under Tropical Cyclone Conditions

In order to best prepare coastal regions for incoming storms, the ability to model tropical cyclone (hurricane) track and intensity has never been more vital. The ocean surface wave field (sea state) may significantly impact the storm intensity forecast because it modifies the air-sea momentum and heat fluxes as well as the upper ocean turbulent mixing. Therefore, it is important to include accurate sea state predictions in hurricane prediction models. The WAVEWATCH III (WW3) is one of the most skillful surface wave models and NOAA plans to incorporate it in the next generation hurricane prediction models. However, WW3 performance under hurricane conditions has not been thoroughly tested and requires further validations against observational data. This study compares the significant wave height (SWH) predicted by WW3 with satellite and Scanning Radar Altimeter (SRA) observational results during Hurricanes Irene (2011) and Edouard (2014). The WW3 data is generated with and without considering ocean currents and with different wind forcing products. The inclusion of currents generally reduces the predicted SWH and improves the correlation between WW3 predictions and observational data. While both SRA and satellite data offer reasonably good correlations with the WW3 data, the standard deviation of the satellite data from the WW3 data is significantly smaller than that of the SRA data. The generally good correlation found between the observational SWH readings and the SWH values from WW3 supports the validity of the WW3 wave model results under tropical cyclone conditions.