Understanding lidar returns from complex dust mixtures
Document ID: 210
Hook, D. Adam
Pangle, Garrett E.
Long, Brandon J. N.
Philbrick, C. Russell
Hallen, Hans D.
North Carolina State University, Department of Physics, Raleigh, NC, U.S.A.
Abstract
Lidar is a powerful tool for measuring the vertical profiles of aerosols. Dusts are irregularly-shaped particles with varied composition and strong variations in index of refraction in the LWIR. We measure dust indices using ellipsometry and transmission through KBr pellets. Milling makes the ellipsometry data less dependent on incidence angle, and the results of measurements on milled materials agree with those from transmission measurements. Measurements show that the spectrum of a milled Arizona Road Dust (ARD) approaches that of pure quartz, indicating that the decrease of absorption efficiency for particles larger than the absorption length substantially affects the results. These indices of refraction are intended for future simulations of extinction for LWIR lidar beams.
Keywords: aerosol scattering, ellipsometry, optical transmission, effective medium theory, index of refraction measurement
| Citation: | "Understanding lidar returns from complex dust mixtures", Hook, D. A., G. E. Pangle, B. J. N. Long, C. R. Philbrick, H. D. Hallen, Laser Radar Technology and Applications XVIII, Vol. 8731, SPIE, 2013, pp. 87310M-1 - 87310M-12, DOI: 10.1117/12.2017698, CCC: 0277-786X/13 |