Study of fluorescence of atmospheric aerosols using a lidar spectrometer

ABSTRACT A lidar for measuring fluorescence from atmospheric aerosols was constructed with a third harmonic Nd:YAG laser, a 1-m diameter telescope, and a 32-channel time-resolved photon counting spectrometer system. Fluorescence of aerosols in the spectral range from 420 nm to 510 nm was studied with the excitation at 355 nm. The distribution of fluorescent aerosols was studied in the time-height indications of the broad fluorescence. Type of the aerosols was identified from simultaneous observation with a polarization lidar in the Asia n dust and aerosol observation lidar network (AD-Net). It was found that Asian dust and air-pollution aerosols transported from urban or industrial areas emit fluorescence. Fluorescence efficiency was roughly estimated for these aerosols. The results suggest fluorescence measurements combined with the measuremen t of microphysical parameters of aerosols using a multiple-wavelength Raman lidar or high-spectral-resolution lidar will provide useful informa tion for characterizing chemical properties of aerosols. Keywords: lidar, aerosol, mineral dust, air po llution, laser-induced fluorescence