A Laser Velocimeter for Remote Wind Sensing

A continuous wave carbon dioxide laser Doppler radar has been developed and applied to remote measurement of atmospheric wind velocity and turbulence. The carbon dioxide laser illuminates residual particulate matter in the atmosphere. Radiation scattered by these particles is homodyned with a local oscillator to provide the Doppler signal. The performance of the instrument is verified by comparison of wind velocity data recorded simultaneously by the laser Doppler system and a cup‐anemometer‐wind‐vane system. Data were recorded, for 45 min intervals, of a single component of the horizontal wind velocity at an altitude of 10 m above the ground. The principle of the laser Doppler system and the theory of the system configuration are presented first, followed by the evaluation of the system. Sample data of a 20 min duration test run of a laser Doppler system are compared with conventional anemometer data. Further comparisons are given of the power spectral densities derived from the two time histories. All d...