气溶胶粒子微观特性对后向散射回波的影响

Influence of Microscopic Characteristics of Aerosol Particles on Backscattering Echo

提出了一种从微观角度分析气溶胶粒子微观特性对后向散射回波影响的方法。基于Mie散射理论,建立了蒙特卡罗仿真模型,对收发同轴激光雷达的气溶胶后向散射回波特性进行仿真分析,得到了气溶胶粒径、复折射率实部及虚部对后向散射回波的峰值强度、信号延迟、波形展宽的影响规律,分析了由气溶胶粒子微观特性引起的多种宏观特性的同时作用对后向散射回波产生的影响。结果表明:后向散射回波强度主要取决于散射系数和不对称因子,回波延迟和脉宽与散射系数相关;随着复折射率实部的增大,后向散射回波强度增加,回波延迟和脉宽先减小后增大,但影响较小;随着复折射率虚部的增大,后向散射回波强度先减小后增大,虚部对回波延迟和脉宽无明显影响。

A method is proposed to analyze the influence of the aerosol particles on the backscattering echo from a microscopic point of view.Based on the Mie scattering theory,a Monte Carlo simulation model is established to simulate and analyze the aerosol backscattering echo by the transmitting and receiving coaxial lidar.The influence law of the aerosol particle size,real part and imaginary part of the complex refractive index on the peak intensity,signal delay and waveform broadening of backscattering echoes is obtained.The effect of the simultaneous action of multiple macroscopic properties caused by the microscopic properties on the backscattering echoes is analyzed as well.The results show that the backscattering signal intensity mainly depends on the scattering coefficient and the asymmetry factor.The echo delay and pulse width are related to the scattering coefficient.As the real part of the complex refractive index increases,the backscattering echo intensity increases,while the echo delay and pulse width decrease first and then increase,but the influence is relatively small.With the increase of the imaginary part of the complex refractive index,the backscattering echo intensity decreases first and then increases,but the imaginary part has no obvious influence on echo delay and pulse width.