Vertical Profile of Wind Speed Over the Open Sea

Abstract

In the pre-GARP experiments in 1969 and 1970, we measured mean profiles of wind speed, air temperature and humidity over the open sea. Many abnormal wind profiles were obtained under the conditions of high wind speeds and swell wave. The wind profiles did not have a logarithmic shape, but had a jet-like flow at about twice as high as wave height.
All of the wind profiles were observed over the open sea about 200-300km away from the land by the use of R/V Hakuho-Maru. Wind speeds were measured by five small threecup anemometers installed along the pole 9.6m away from the bow, and wave heights were observed by the gyroscope, accelerometer and sonic wave gauge.
Overspeeding of the cup anemometers, ship movements and thermal stratification of the air layer were taken into account for obtaining the wind profiles.
Our conclusions are as follows:
As a mean wind speed increases on the open sea with significant swell waves, a departure from a logarithmic wind profile becomes larger, and obvious two peaks in the profile are recognized corresponding to the wave height distribution with two maxima.