Lidar Detection of Sub-Visible Cirrus Clouds

Abstract

Cloud measurements using a ground based NdYAG Lidar operating at a wavelength of 0.53 um showed important backscatter returns from an altitude of approximately 12 km. during visually clear atmospheric conditions. The Lidar return signal is attributed to sub-visible cirrus clouds having backscatter ratios of 6.1 to 7.6 and a backscatter coefficient of 2.64 to 3.43 x 10(E-03) /km/sr. The measurements were taken during the FIRE (First International Satellite Cloud Climatology Project Regional Experiment), IFO (Intensive Field Observations) in Wisconsin during October and November 1986. The results are compared with collaborative measurements (eg. satellite, air sampling, radiometric etc. during the FIRE trials), Lidar data from Langley Research Center (LaRC) and literature results.