Measurements of Wind Speeds with an Optical Crossbeam System

An optical crossbeam technique has been developed for the remote sensing of atmospheric winds. The feasibility tests of a complete system are reported. The initial crossbeam system was found to measure atmospheric winds within ±20 percent of those measured with cup anemometers on a meteorological tower. The system consists of two telescopes (light beams) which collect light along narrow beams. The collected light is measured by photodiodes. The light is found to fluctuate in intensity due mainly to scattering by aerosols. The light source is available skylight only. The fluctuations in light are related to the convective wind velocity by employing space-time correlation techniques.