Polarization lidar at <inline-formula><math altimg="none" display="inline" overflow="scroll"><mrow><mn>1.54</mn><mspace width="0.3em" /><mi>μ</mi><mi mathvariant="normal">m</mi></mrow></math></inline-formula> and observations of plumes from aerosol generators

Abstract

The ability to detect relative changes in backscatter polariza- tion from a scanning high-pulse-energy lidar system at 1.54-m wave- length is demonstrated. The new capability was tested during the dis- semination of various biological aerosol simulants and other particulate emissions at the U.S. Army's Dugway Proving Ground. Results demon- strate that the lidar is sensitive to different types of aerosols, and depar- tures from the atmospheric background depolarization ratio are consis- tent with the limited amount of information available on the degree of particle sphericity. We conclude that the polarization-sensitive coatings of the beam-steering unit mirrors are presently the largest source of error and that this error is minimized when scanning with a near-zero elevation angle. This is an encouraging result for aerosol source surveillance ap- plications, where the depolarization information may be useful in deter- mining the aerosol generation mechanism or provide an additional scalar variable for use in delineating the plume from the background. © 2007