Observations of Wave Development in Gusty Winds

Abstract Wave and meteorological observations from free‐drifting buoys deployed during four field campaigns were collated to evaluate the impact of wind gustiness on wave evolution. Met‐ocean conditions included wind speeds up to 25 m/s and mixed seas and swell. Analysis of bulk characteristics indicates that wave heights in gusty winds are 20%–50% larger than wave heights in steady winds. Spectral characteristics, including the peak frequency, peak energy, and spectral tail shape, indicate more developed waves in gusty winds than steady winds for the same mean wind speed. Observed spectral differences are linked to wind‐wave growth through analysis of mean square slope, equilibrium friction velocity, and growth rate. The total energy input to the wave spectrum and the actively forced frequencies differ between gusty and steady winds. Results support hypotheses of a higher “effective” wind in gusty conditions and emphasize the need for robust formulation of gustiness in wave models.