Estimates of Probability of a Cloud-Free Line of Sight for RAPTOR TALON.

RAPTOR TALON is a concept that includes optical sensing of rocket plumes from low altitudes 2 km through burnout from an air vehicle at 18-20 km, at a long range, i.e., R approx. 20-100 km. The presence of clouds can interfere with optical sensing, and thus it is important to establish the Probability of a Cloud-Free Line of Sight PCFLOS at locations and times of concern. Some previous estimates of PCFLOS were counter-intuitive and provided varying results POET was asked to resolve the discrepancies. Here we ask for the PCFLOS for paths from 18 km altitude above all clouds to 2 km, at a slant range of about 20 - 100 km at two different locations Baghdad, Iraq, and Seoul, Korea for January and July at average cloudiness There are very few clouds in Iraq during the summer, so for this case PCFLOS - 0.9 - 0.95. At the other locations and seasons the mean cloud cover ranges between 0.4 and 0.7, and the POFLOS values range between 0.6 and 0.7 at P 20 km, and between 0.4 and 0.6 at P 100 km. Estimates made by a variety of methods are generally consistent with this finding.