Polarization And Dual Wavelength Aerosol Scheimpflug Lidar (SLidar) Technology Research

The current environmental problems have become increasingly prominent,and the prevention and control of atmospheric pollution has become an urgent task.As an active remote sensing technology,atmospheric lidar technology has great advantages in real-time monitoring of environment.Although the traditional pulsed laser radar technology is relatively mature in environmental monitoring.However,the complexity of the light source and detector,high cost,high maintenance requirements limits the applications.The research goal of this paper is to use the new atmospheric lidar technology to solve the challenges of the traditional pulsed lidar techniques,optimize the system performance and improve the system stabilities.Besides,atmospheric applications of the Scheimpflug lidar?SLidar?technique in aerosol extinction retrieval,depolarization studies and NO₂ monitoring are also developed.This thesis first introduces the generation and classification of atmospheric aerosols,and the effects of atmospheric aerosols on human health,ecological environment and climate change.Then the transmission characteristics of lasers in the atmosphere is discussed.The basic principle of Scheimpflug and the application of this principle in atmospheric laser radar technology are investigated.In the meanwhile,the retrieval algorithm of the extinction coefficient is introduced.In this thesis,four aspects of research work have been carried out:the single-wavelength scatter SLidar technology,the Mie-scattering polarization SLidar technique,the dual-wavelength SLidar technique,and the differential absorption SLidar technique.The first three aspects are aimed at the studies on atmospheric aerosol particles,where the distribution,particle morphology,and particle size information of atmospheric aerosol particles can be qualitatively or quantitatively detected.The fourth aspect is to measure range-resolved concentration of NO₂in the atmosphere.Although the concentration of NO₂ in the environment is very low,the concentration distribution can still be measured by the differential absorption lidar?DIAL?based on the SLidar technique.The experimental results show that the correlation coefficient within the measurement distance of 0.3 km-1 km is about 0.94,which verifies that DIAL technique has great potential in monitoring NO₂ concentration.The work provides optimized system parameters for the SLidar technique,and have pave the way for the SLidar technique in the applications of remote sensing,such as time-space distribution of atmospheric pollution,depolarization of particles and NO₂ concentration.