Share Email Print
cover

Proceedings Paper

Wide-angle imaging lidar (WAIL): a ground-based instrument for monitoring the thickness and density of optically thick clouds
Author(s): Steven P. Love; Anthony B. Davis; Charles A. Rohde; Cheng Ho
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Traditional lidar provides little information on dense clouds beyond the range to their base (ceilometry), due to their extreme opacity. At most optical wavelengths, however, laser photons are not absorbed but merely scattered out of the beam, and thus eventually escape the cloud via multiple scattering, producing distinctive extended space- and time-dependent patterns which are, in essence, the cloud's radiative Green functions. These Green functions, essentially 'movies' of the time evolution of the spatial distribution of escaping light, are the primary data products of a new type of lidar: Wide Angle Imaging Lidar (WAIL). WAIL data can be used to infer both optical depth and physical thickness of clouds, and hence the cloud liquid water content. The instrumental challenge is to accommodate a radiance field varying over many orders of magnitude and changing over widely varying time-scales. Our implementation uses a high-speed microchannel plate/crossed delay line imaging detector system with a 60-degree full-angle field of view, and a 532 nm doubled Nd:YAG laser. Nighttime field experiments testing various solutions to this problem show excellent agreement with diffusion theory, and retrievals yield plausible values for the optical and geometrical parameters of the observed cloud decks.

Paper Details

Date Published: 19 September 2001
PDF: 12 pages
Proc. SPIE 4377, Laser Radar Technology and Applications VI, (19 September 2001); doi: 10.1117/12.440109
Show Author Affiliations
Steven P. Love, Los Alamos National Lab. (United States)
Anthony B. Davis, Los Alamos National Lab. (United States)
Charles A. Rohde, Los Alamos National Lab. (United States)
Cheng Ho, Los Alamos National Lab. (United States)


Published in SPIE Proceedings Vol. 4377:
Laser Radar Technology and Applications VI
Gary W. Kamerman, Editor(s)

© SPIE. Terms of Use
Back to Top