Characterization of Rogue Wave Occurrence During Typhoon Hinnamnor Using Directional Wave Spectra and High-Order Spectral Simulations

Abstract Rogue waves often occur unexpectedly during severe weather conditions, such as typhoons, where rapidly evolving sea states enhance nonlinear wave interactions. Typhoon Hinnamnor, one of the most intense storms in the Northwest Pacific during 2022, generated a sequence of extreme sea states that provide a valuable case for investigating rogue wave dynamics. Among them, two contrasting phases are analyzed: a wind-sea-dominated state before intensification and a swell-dominated state after re-intensification. Phase-resolving simulations are conducted using the Higher-Order Spectral (HOS) method, initialized with directional wave spectra from WAVEWATCH III (WW3) hindcast data. Key statistical parameters including wave skewness and excess kurtosis are examined to assess their roles in extreme crest formation. The HOS-simulated wave fields clearly capture the probability of highly nonlinear extreme crests, showing strong agreement with the Tayfun second- and third-order distribution models, while deviating significantly from the Rayleigh distribution base on linear theory. Results also reveal that rogue waves are more likely to occur in positively skewed sea states, emphasizing the importance of second order bound nonlinearities. In contrast, excess kurtosis remains near zero with a slight positive bias, indicating a limited role of third-order modulational processes. Probability density functions, cumulative distributions, and exceedance analyses further support the strong link between skewness and rogue wave probability. These findings underscore the critical role of evolving directional wave spectra in shaping nonlinear wave statistics and provide valuable insights for improving rogue wave prediction and maritime safety in storm-driven sea states.