The dependence of offshore turbulence intensity on wind speed

Four years of 10 min mean wind data from the offshore measuring platform FINO1 (Forschung in Nord-und Ostsee 1) in the German Bight have been analyzed to obtain the dependence of turbulence intensity on the wind speed. The investigated dataset is unique in so far as no high quality long-term measurements with a height resolution of 10 m at heights between 33 and 103 m and a minimum distance to the coast of 45 km have been available so far.Wave height and therefore sea surface roughness and turbulence intensity increase with increasing wind speed. The influence of the surface roughness decreases with height. Results are compared to previous results and to the specifications given by the IEC wind turbine standards 61400-1 and 61400-3.