An Automated Observing System for Passive Evaluation of Cloud Cover and Visibility

Abstract : The Automated Observing System is a passive system for determination of cloud cover and sector visibility. This system was developed from related systems, the Whole Sky Imager for cloud field assessment, and the Horizon Scanning Imager for determination of the sector visibility. During the past funding interval, much of the effort on this system was directed toward development of night visibility capability. This report discusses the theoretical development of the equations and analytic approaches to night visibility. A variety of hardware and software adaptations are discussed, which allow the sensor to utilize multiple integration periods for increased system sensitivity. Sample results are included. Secondary developments discussed in this report include an in-depth sensitivity analysis of the daytime visibility system, as well as achievement of more accurate cloud algorithms and night cloud capability funded separately. This is followed by recommendations for improvements to tile current system, and for development of tactical systems based on the existing capability.... Visibility, Contrast transmittance, Atmosphere, Sector visibility, Weather sensors, Aviation weather observations, Weather, Atmospheric visibility, Cloud, Cloud cover, Cloud free line of sight.