Rogue wave indicators from global models and buoy data

Abstract. Rogue waves pose substantial risks to maritime operations and offshore infrastructure, yet their formation mechanisms and predictability remain poorly understood. This study analyses real rogue wave occurrences using in situ observations from CDIP wave buoys from the Free Ocean Wave Data (FOWD) dataset and model-based estimates from ERA5 reanalysis and the ECMWF CY47R1 high-resolution hindcast. Seasonal distributions, wave height comparisons, and spectral analyses reveal that models systematically underestimate extreme wave events due to spectral smoothing and spatial averaging. A key finding is that rogue waves are usually preceded by a sharp decrease in crest-trough correlation below 0.5, followed by a rapid increase usually above 0.6, indicating a transition to a more structured wave field. This pattern, accompanied by spectral bandwidth narrowing and increased relative energy in the 0.25–1.5 Hz range, suggests energy focusing mechanisms play a critical role. Analysis of rogue wave events at four CDIP buoy stations show that the crest-trough correlation parameter alone is not a good rogue wave indicator, but its temporal variability is. These results highlight the need for improved modelling by integrating dynamic wave field specific parameters and high-resolution numerical models to enhance rogue wave risk assessments on a global scale.