wind velocity measurements using sonic techniques1

Abstract

A unique technique has been devised to measure wind speed and direction in space without any local sensor, artificial target, or any structure erected over the ground being necessary. Continuous recordings of wind speed and direction at a distance of 70 ft from a sonic source have been obtained by measuring the frequency shift of sonic waves scattered from a narrow beam generated by a powerful Levavasseur whistle at 10 kc. Two receivers in orthogonal directions with respect to the source provide continuous readings of the horizontal components of wind velocity. The series of over 300 sonic measurements on winds from 3 to 25 mph show average difference readings compared with an Aerovane anemometer not larger than ± 1.0 mph for speed nor ± 5.0° for direction, indicating a high degree of correlation between the sonic system and the more commonly used propeller type anemometers.