Enhanced ocean wave modeling by including effect of breaking under bothdeep- and shallow-water conditions

Accurate description of the wind energy input into ocean waves is crucial toocean wave modeling and a physics-based consideration on the effect of wavebreaking is absolutely necessary to obtain such an accurate description.This study evaluates the performance of an improved formula recentlyproposed by Xu and Yu (2020), who took into account not only the effect ofbreaking but also the effect of airflow separation on the leeside of steepwave crests in a reasonably consistent way. Numerical results are obtainedthrough coupling an enhanced atmospheric wave boundary layer model with theocean wave model WAVEWATCH III (v5.16). The coupled model has been extendedto be valid in both deep and shallow waters. Duration-limited waves undercontrolled normal conditions and storm waves under practical hurricaneconditions are studied in detail to verify the improved model. Both therepresentative wave parameters and the parameters characterizing the wavespectrum are discussed. It is shown that the improved source-term packagefor the wind energy input and the wave energy dissipation leads to moreaccurate results under all conditions. It performs evidently better thanother standard source-term options of ST2, ST4 and ST6 embedded in WAVEWATCHIII. It is also demonstrated that the improvement is particularly importantfor waves at their early development stage and waves in shallow waters.

Automated summary

Accurate description of wind energy input into ocean waves is crucial for wave modeling. This study evaluates the performance of an improved formula that considers the effect of wave breaking and airflow separation on steep wave crests. Coupling an enhanced atmospheric wave boundary layer model with the ocean wave model WAVEWATCH III, numerical results show that the improved model leads to more accurate results under all conditions, with better performance than other standard options. The improvement is particularly important for waves in their early development stage and in shallow waters.