Turbulent properties and spectral behaviours of ocean winds observed at an off-shore tower

Various characteristics of the atmospheric turbulence above the open sea were estimated by analysing three-dimensional wind fluctuations, which were observed at two levels of an off-shore tower under the condition of long lasting strong winds. Gust factor, turbulent intensities of three wind vectors and drag coefficient were shown to be functions of wind speed. Spectrum of longitudinal velocity in very wide frequencies was obtained and its behaviours were discussed. Dependency of vertical correlation and eddy coherence to mean wind speed were evaluated for large scale eddies in the atmospheric boundary layer.