The Visioceilometer: A Portable Cloud Height and Visibility Indicator

Abstract : The first experimental prototype (model-1) visioceilometer has been developed. It measures cloud height from 50 to 3000 meters with 10-meter accuracy and calculates visibility from a sample volume up to 1 kilometer in length of the lidar return. It consists of a hand-held, battery-operated lidar which uses the AN/GVS-5 laser rangefinder optics. Measurements of visibility in fog and cloud ceiling height in clear air and rain were taken at the fog dispersion test facility at Otis Air Force Base, MA. In relatively homogeneous fogs, the visibility accuracy was comparable to standard transmissometers. The cloud ceiling accuracy was also comparable to the standard rotating beam ceilometer.