COMPARSION OF LIDAR AND TRANSMISSOMETER MEASUREMENTS THROUGH CLOUDS

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Authors
  1. Bissonnette, L.R.
  2. Kunz, G.
  3. Weiss-Wrana, K.
Corporate Authors
Defence Research Establishment Valcartier, Valcartier QUE (CAN)
Abstract
A lidar-transmissometer intercomparison was made during an international experiment held in the German Alps to characterize the vertical structure of aerosols and clouds. The transmission path was 2325-m long and inclined at 30 degrees along the slope of a steep mountain ridge. The transmissometer consisted of a Nd:YAG and a CO2 laser located in the valley and a large-mirror receiver that captured the full beams on the mountain top. Two lidars, one at 1.06 mu m and one at 1.054 mu m, were operated with their axes approximately parallel to the transmissometer axis but separated by a horizontal distance on the order of 20-40 m. The first one was operated in retroreflector mode and the relative transmittance was determined from the reflection off the mountain ridge above the cloud layer. The second one had a special receiver designed to make simultaneous recordings at four fields of view. The range-resolved scattering coefficient and effective cloud droplet radius are calculated from these four-field-of-view measurements by solving a simplified model (App. Opt. 34, 6959-6975, 1995) of the multiply scattered returns. The two simultaneous solutions for the scattering coefficient and effect droplet size make possible extrapolation at wavelengths other than the lidar wavelength of 1.054 mu m. The main measurement event analyzed in this paper lasted 1.5 hours and produced transmittances ranging from less than 5% to more than 90% TRUNCATED
Keywords
Laser radar;Field of view;Lidar inversion
Date of publication
30 Aug 1996
Number of Pages
13
Reprinted from
SPIE, vol 2828, 1996, p 150-161
DSTKIM No
97-00284
CANDIS No
500611
Format(s):
Hardcopy;Document Image stored on Optical Disk

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