Weather identifier for snow, rain, and drizzle

摘要

A weather identification system is provided which employs a first photosensitive receiver positioned directly in the path of a beam of light a predetermined distance from a partially coherent light beam source. The first photosensitive receiver is in direct optical communication with the light beam source to produce electronic signals in response to scintillations caused by particle movement between the source and the first receiver. A second photosensitive receiver is positioned out of the path of the beam of light and is oriented at an oblique angle relative thereto to provide an output indicative of forward scattering of light from scintillations that occur in the beam of light. The signals from the second photosensitive receiver are AC coupled to provide an output indicative of rate of fluctuation and having a signal strength characteristic that even distinguishes between light drizzle and fog. The weather identification system thereby senses precipitation, categorizes the precipitation as either rain or snow, and drizzle. The weather condition indicating system is ideal for use in remotely monitoring airfields.