Wavenumber Dependence of Short Wave Roughness during Variable Winds

Abstract:

Short-scale sea surface waves are of profound importance to most air-sea interaction processes.Here we study regime-specific contribution to the surface roughness and the sea surface sensitivity to short time-scale wind speed fluctuations. Shipboard measurements were made via polarimetric camera (following Laxague et al., 2015 and Zappa et al. [2008]), resolving wavelengths ranging from 0.21 m to 0.003 m (30 rad/m <k < 1800 rad/m). The gravity-capillary regime was found to contribute the bulk of mean square slope duringstationary wind conditions and supply the majority of mean square slope growth during periods of increasing wind speed. Capillary waves were found on average to contribute a small fraction of the overall surface roughness and to be the least sensitive to increases in wind speed due to saturation. These results offer insight for scientists in the remote sensing field and important information for the creation of new wave models.