Spectral characteristics of surface-layer turbulence in the North Sea

For wind velocities ranging from 14 m s-1 to 28 m s-1, a good agreement is observed between the Kaimal spectra and the measured ones, although the power spectral density of the wind fluctuations is larger than predicted for reduced frequencies below 0.04. The Mann spectral model showed a good agreement with the measured spectra. At the altitude of 80 m, we found in average Γ = 3.7, αϵ2/3 = 0.04 m4/3s2 and L = 70 m. Finally, the NORSOK spectrum agrees fairly well with the measured one if a Charnock coefficient of 0.011 is used.