Field observation of wind velocity at an observation station in Ohsaka Bay about 450km west from Tokyo has been carried out since 1978. Seven aerovane type anemometers and two three-dimensional sonic anemometers are installed to the observation towers constructed on the shore in order to know properties of strong wind of above sea.
　23 records of wind velocity are analyzed. The mean wind velocities of them are in the range of 13 to 21m/s. The summary of the results from the field observatio
n is shown below:
1) Gust factors for 10 minutes at 15m height in the sea are in the range between 1.2 and 1.4.
2) Dominant frequencies of logarithemic spectrum in horizontal wind component are about 0.03Hz. The properties of the spectrum of the observation records coincide with the properties of spectrums proposed by Davenport and by Hino in the range of 0.02 to 5Hz.
3) Coefficients of power index presenting the wind profile of the perpendiculer direction at the observation tower with 100m height are in the range of 5 to 6 for winds from sea.
4) The vortics of turbulance in wind are oval-shaped. The alongwind scales of the vortics are in the range of 50 to 250m. The lateral scales are smaller than the alongwind scales.