Lund Iver A. Atlas of cloud-free line-of-sight probabilities. Part 3. United States of America

Air Force Cambridge Research Labs, Hanscom, AFB, MA, 1977. — 73 p.This is the third part of a planned Northern Hemisphere atlas of probabilities of cloud-free lines-of-sight between the earth and space. The probabilities are for the mid-season months: January, April, July, and October; four times of day: 0000-0200 LST, 0600-0800 LST, 1200-1400 LST, and 1800-2000 LST; and three elevation angles: 10, 30, and 90 degrees. Parts 1 and 2 depicted cloud-free line-of-sight probabilities for Germany and the USSR respectively.