大气中气溶胶颗粒对红外激光的散射特性研究

在利用红外激光雷达探测大气中各种成分浓度时，研究大气中气溶胶颗粒在该红外波段的光学散射特性有重要意义.特别是大气中气溶胶颗粒的散射系数和后向散射率是基于红外激光雷达探测大气后向散射回波信号的重要参量，直接影响探测系统的测量精度和有效探测距离.根据等效球的米氏散射理论，分析大气气溶胶颗粒在该波段的散射效率因子和散射相函数，可准确计算出不同半径和不同密度时大气气溶胶颗粒的散射系数和后向散射率大小.利用仿真模型计算得出，当大气气溶胶颗粒的半径增加时，其散射效率因子的数值振荡衰减，最终稳定于2.04处；而当入射激光波长不变时，大气气溶胶颗粒的后向散射率数值与其半径的变化呈反比.

Analyzing the scattering characteristics of aerosol particles to infrared laser in the atmosphere

It is of great significance to study the aerosol particles optical scattering properties in this band when using the infrared lidar to measure the atmospheric various components concentration. Especially the scattering coefficient and the backward scattering ratio of aerosol particles are important parameters for receiving scattering echo signal based on infrared lidar. It directly affects the precision and effective detection distance about the detection system. According to the Mie scattering theory， we can analyze the scattering efficiency factor and the scattering phase function of atmospheric aerosol particles. And we can accurately calculate the scattering coefficient and the backward scattering ratio of aerosol particles about different radius and different density. The simulation results show that with the increase of aerosol particles radius， the scattering efficiency factor is vibrations and the amplitude decreases gradually and finally it tends to near 2.04. On the condition of the constant wavelength， the backward scattering ratio of the atmospheric aerosol particles decreases with the increase of their radius.