Sensitivity and impact of atmospheric forcings on hurricane wind wave modeling in the Gulf of Mexico using nested WAVEWATCH III

Precise estimation of hurricane wind-induced waves is critical to enhance the accuracy of predicting coastal flooding events in real-time besides helping in the design of sustainable coastal/offshore structures. In this study, we aim to investigate the importance of atmospheric forcings and their impact on wind wave modeling for extreme hurricane conditions in the Gulf of Mexico (GOM) basin. Hurricanes Michael (2018) and Ida (2021) were chosen to be modeled as they were among the two most severe storm events that attained category 5 and category 4 status, respectively, during landfall in the GOM basin. A multi-grid nested modeling approach was implemented in WAVEWATCH III with three different wind forcings: ECMWF's ERA5, NOAA's High-Resolution Rapid Refresh (HRRR: v3 and v4) and ECMWF's Operational High-Resolution Forecast Model (ECMWF) to model both hurricanes. The results generated through model simulations of various cases were compared with the field observations obtained at NDBC stations. One of the findings suggests that the ERA5 based wind model substantially underestimates the peak winds of both the hurricanes by 50–60 %, thereby resulting in significant underestimation of the wave heights by 40 %. Although the ECMWF model could not capture the maximum winds generated by Michael and Ida, it still gave better results than the ERA5 and HRRR (v3). The updated version (v4) of HRRR performed better than both ERA5 and ECMWF wind models in predicting the peak wind speeds and wind field distribution of Hurricane Ida in all the quadrants.