Wavenumber spectrum of intermediate-scale ocean surface waves

This paper presents an analysis of the wavenumber spectra of intermediate-scale waves (wavelengths between 0.02 and 6 m) under various sea-state conditions. The main result of the analysis is that the dependence of the dimensionless wave spectrum on the dimensionless wind friction velocity follows a power-law function. The coefficient and exponent of the power-law function vary systematically with the wavenumber. The wavenumber dependence of the coefficient and exponent serves as an empirical parameterization for computing the wavenumber spectra of intermediate-scale waves at different wind speeds. Calculation of the mean-square slope from the resulting wavenumber spectrum confirms that intermediate-scale waves are the dominant contributor of the ocean surface roughness. A simple formula is presented for calculating the band-pass filtered mean-square slope of the ocean surface for remote sensing applications.