An improved calibration method and detection error simulation for three-wavelength polarization lidar systems

Abstract

Polarization lidar plays an important role in detecting the microphysical properties of non spherical aerosol particles in the atmosphere and the indirect interaction between aerosols and clouds. However, there are various complex optoelectronic components in polarization lidar systems, and the imperfect nature of these components often poses difficulties for the system to accurately receive data. To ensure the accuracy of the detection data of a multi wavelength polarization lidar system, precise calibration of the system is a crucial step. This article is based on a three wavelength (355nm, 532nm, 1064nm) polarization lidar system. Based on the ± 45 ° polarization lidar system calibration method proposed by Freudenthaler et al, an improved calibration method is designed to calibrate different wavelength detection channels. The new calibration method corrects some issues with the ± 45 ° method and proposes a calculation method to reduce the impact of cascading multiple dichroic mirrors on the received Signal The simulation results show that the use of the average polarization error angle successfully reduces the impact of cascading multiple dichroic mirrors on the signal. At the end of the article, we validated the error analysis of the proposed method under different detection wavelengths through simulation calculations. The results show that when detecting extremely small atmospheric particles such as atmospheric molecules, the detection error is around 6%. When detecting non spherical particles with a depolarization ratio greater than 0.1, the error of each detection channel can be reduced to less than 3%.