Fog Bank Detector Field Tests: A Technical Summary.
Technical rept. Sep 71-Dec 71,
TRANSPORTATION SYSTEMS CENTER CAMBRIDGE MASS
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The report summarizes the results of field experiments performed at Pt. Bonita, California. The system under study, a laser LIDAR and a vertical-scanning infrared radiometer, have been discussed in detail in Report No. DOT-TSC-CG-71-3. Measurements of the peak power and shape of the return LIDAR pulse, and of the background levels, support the assumptions made in that report. The largest value of background spectral radiance measured, when a sunlit cloud fills the LIDAR receiver field-of-view, is 2 micro wsq cmAsr at 6943A. The infrared radiometer was found to be susceptible to ambiguities serious enough to eliminate this method from use as a reliable fog detector at the present time. Based on the laser backscatter results, a LIDAR fog bank detector, using a GaAlAs laser diode array as the transmitting source, is recommended and conclusions regarding its technical performance are presented.