Universal Methods for Estimating Probabilities of Cloud-Free Lines-of-Sight Through the Atmosphere

Abstract
More than three years of 3-hr high-contrast whole-sky photographs, sky-cover observations, and cloud-type observations were utilized to develop two methods for estimating cloud-free line-of-sight probabilities through the entire atmosphere for any desired geographical location. One method acquire a knowledge of the probability of each sky-cover category (tenths or eighths); the other method requires both sky-cover and cloud-type information.