A new LIDAR system for the detection of Cloud and aerosol backscatter, depolarization, extinction, and fluorescence

摘要

We present a newly designed Compact Cloud and Aerosol LIDAR (ComCAL) that was built for the deployment in field campaigns on ground and on mobile platforms like aboard the research vessel Polarstern. The automated system is particularly suited for troposphericaerosol research within the altitude range from 0.7 to 20 km. As emitter it uses a frequency doubled and tripled Nd:YAG laser. It measures elastic backscatter and the depolarization at 532 nm and 355 nm as well as inelastic scattering with a 32-channel spectrograph.Recently, it was shown that biomass burning aerosol fluoresces when irradiated by a UV laser beam while other aerosol types do not fluoresce [1]. Beside the detection of N2 and H2O Raman scattering, fluorescence of aerosols can be detected by the new optical set-up of our lidar system. The measurement of wavelengths dependent backscatter, extinction, depolarization,and fluorescence makes a detailed study of atmospheric aerosols possible. The new lidar system determines optical properties of aerosols and their vertical distribution. The aerosol types, their origins and abundancecan be deduced from that data. These are important parameters for the study of the effect of natural and anthropogenic aerosols on the earth¡Çs climate.