Monitoring of the particles above the unpaved road by lidar technique

Abstract

Basic concepts of laser-based technique LIDAR (LIght Detection and Ranging) are discussed in this article as well as advantages and disadvantages. Presented are measurements of relative particulate concentrations above an unpaved road which were performed in a rural area near the Iowa City, Iowa, USA. The LIDAR system used in these measurements is a small, scanning LIDAR that uses elastic backscattering to obtain information on the amount of atmospheric aerosols. In the elastic LIDAR, light scattered back towards the LIDAR system from molecules and particles in the atmosphere is collected by a telescope and is detected with a photodiode. A Big Sky Laser model CFR-200 Nd:YAG laser operating at 1.064 microns is used to generate the LIDAR's outgoing signal. The laser is attached directly to the top of a 26 cm, f/10 Cassegrian telescope. A series of pulses are summed to make a single scan. A series of scans is used to build up a twodimensional map of relative atmospheric aerosol concentrations. With a maximum range of about 6-8 km, a range resolution of 2.5 m, and a time resolution of 30 s, the LIDAR is capable of very detailed mapping of aerosols.