Dual-wavelength High-Spectral-Resolution Lidar for advanced classification and retrieval of aerosols

A two-wavelength High-Spectral-Resolution Lidar (HSRL) system is developed. This lidar system provides 2α+3β+2δ data: extinction coefficients (α) at 355 and 532 nm, backscatter coefficients (β) at 355, 532, and 1064 nm, and depolarization ratios (δ) at 532 and 1064 nm. This system combines use of the previously developed HSRL techniques with an iodine absorption filter for 532nm and a Fabry-Perot etalon for 355nm. To realize temporally continuous measurements, we also develop a system to tune the laser wavelength to an iodine absorption line and then automatically tune the Fabry-Perot etalon to the third harmonic of the laser. We conducted preliminary measurements using the constructed systems. The temporal and vertical variation of aerosols could be determined. The constructed 532nm HSRL system could measure molecule Rayleigh backscatter signals by blocking aerosol Mie backscatter signals with the iodine absorption filter, indicating that the developed laser wavelength tuning system worked well.