Aerosol Optical Thickness Measurement with Elevation-Scanning Lidar

High-accuracy measurement of aerosol optical thickness (AOT) τa with an elevation-scanning lidar is demonstrated and the results are compared with a collocated Cimel 318 sun photometer. Linear regression of the time-coincident data from a 2-week measurement campaign with the two instruments is found to be τalidar = (1.00 ± 0.17)τaphot + (0.025 ± 0.019) (1σ). The method proved to have sufficient accuracy to measure AOTs of 0.1–0.2 commonly seen in relatively clear atmosphere. The measurement is absolute and thus does not depend on any external calibration standards.