TERRESTRIAL PHOTOGRAMMETRY OF CLOUDS

Abstract

Measurements of heights of clouds and the vertical velocities and accelerations of cloud outlines can be made from stereo pairs of photographs taken at regular time intervals. Two methods of obtaining these measurements for individual cloud features are explained. The first is a graphical procedure and the second is a method utilizing direct parallax measurements from the two photographs. Accuracies of 100 to 300 feet in height and 0.1 to 0.7 mile in range at 13 mile ranges are claimed. Information on the change with time of the entire cloud outline can be obtained via a stereoscopic planimetric method. This method is explained and sample results of cloud tracings and cloud growth rates are presented.