Some effects of buoy motion on measurements of wind speed and stress

In the past few years a number of observations have been made at sea of the wind speed gradient and the turbulent Reynolds stress. It is of considerable interest to make some estimates of the effect of buoy motion on the measurements, particularly since the measurements from buoys and fixed masts show marked differences. The calculations are quite simple if we use fairly simple motions to approximate the behavior of the buoy. Provided that some damping is done of the vertical motion and provided that the amplitude of the oscillating tilt is smaller than 10°–20°, the effects are fairly small. The error arising from the correlation between the turbulent velocity components and the components produced by the buoy motion is probably 10–20%. It is shown, however, that it is extremely important to keep the mean tilt very small.