Measurement of Cloud Height, Evaluation of Ranging and Triangulation Techniques for Determination of Cloud Height at Airfields.

摘要

A new evaluation of a ruby lidar ceilometer was performed at AFCRL as part of a program to evaluate the applicability of lasers to determine cloud height for airfield use. Comparitive measurements of cloud height were made with a standard Air Force rotating beam ceilometer (RBC). Examination of the test results shows the lidar indicates an accurate presentation of cloud structure. The RBC cloud return is affected by its geometry and by multiple scatter in the cloud. As a result, the measurement is not a true representation of cloud structure. These effects also bias the RBC to indicate higher cloud heights. However, the difference in cloud heights as measured by the two systems is not significant. Therefore, it is concluded that the lidar is a superior cloud height measuring device and both techniques provide operationally useful indications of cloud height. (Author)