Laboratory measurements of the transmission and scattering of laser beams in optically dense aerosols.

摘要

Lidar has a large range of potentially useful applications in the area of remote sensing. Unfortunately the analysis of lidar data is handicapped by a lack of understanding of how the scattering generated in scattering media affects the measured lidar signal. This thesis describes the development and use of a sophisticated laboratory scattering facility developed to study many aspects of the scattering in dense aerosol media. Through a number of innovative measurement techniques measurements having unprecedented sensitivity and capabilities have been performed. The primary concern of these measurements was the study of the forward scatter generated as a laser pulse propagates through a scattering medium and how this forward scatter subsequently affects the measured lidar return. The results show that the forward scatter can be very important, causing very large deviations from the normally assumed behaviour. These measurements suggest that the forward scatter has a much more important role to play in lidar measurements than previously thought. In addition to illustrating the effect which the forward scatter can have, methods of reducing its influence are also studied.