Spectral characterization of fine-scale wind waves using shipboard optical polarimetry

Fine-scale sea surface waves are of profound importance to a number of air-sea interaction processes. Due to a number of reasons, there exists a great degree of difficulty in obtaining quality in situ observations of these waves. This paper presents the application of a shipboard wave-sensing method toward the following quantifications: regime-specific contribution to sea surface slope and sensitivity to wind speed increases. Measurements were made via polarimetric camera, resolving waves with wavelengths ranging from 0.21 to 0.003 m (30 rad/m< k< 1750 rad/m). The gravity-capillary regime was found to contribute the bulk of mean square slope during stationary wind conditions and supply the majority of mean square slope growth during periods of increasing wind speed. Capillary waves were found to contribute approximately 5% of the overall surface roughness. Furthermore, capillary waves were found to be the least sensitive to increases in wind speed. This implies that such waves saturate at low wind speeds ( 3 m/ s) and slow wind speed increases ( 0.02 m=s2). The slight roughness contribution from capillary waves and significant contribution from gravity-capillary waves offers insight for scientists in the remote sensing field and important information for the formation of new wave models.