非球形气溶胶粒子光散射特性的仿真分析

Analysis of light scattering properties of non-spherical aerosol particles

基于DDA法研究了复折射率、粒子形状和尺度参数对非球形气溶胶光散射特性的影响。仿真结果表明,气溶胶粒子的消光效率因子和散射效率因子随尺度参数增加呈减幅振荡。当复折射率实部增加时,消光效率因子和散射效率因子的振荡周期减小,而吸收效率因子略微增加;当复折射率虚部增加时,散射效率因子的振荡幅值和振荡中心值减小,而吸收效率因子显著增加。复折射率虚部增大时,椭球气溶胶粒子群的雷达比增大,退偏比减小。在近瑞利散射区,粒子形状对粒子的光散射特性影响较小,在米散射区时,粒子光散射特性与粒子形状密切相关。消光效率因子和散射效率因子随尺度参数变化的振荡幅值、周期和中心值一定程度上也反映了椭球形气溶胶粒子的非球形特征。

The effects of complex refractive index, particle shape and size parameter on the light scattering properties of non-spherical aerosols are studied based by the discrete dipole approximation method. The simulation results show that when the size parameter increases, the extinction efficiency factor and the scattering efficiency factor oscillate with the amplitude decreasing. The oscillation period of extinction efficiency factor and the scattering efficiency factor of the ellipsoidal aerosol particles decreases with the real part of complex refractive index increasing, with the absorption efficiency factor slightly increasing. The oscillation amplitude and the central position of the scattering efficiency factor decrease with the imaginary part of complex refractive index increasing ,with the absorption efficiency factor increasing significantly. When the imaginary part of complex refractive index increases,the lidar ratio of ellipsoidal aerosol particles increases and the depolarization ratio decreases. When close to Rayleigh domain, the shape has little influence on the light scattering properties of particles. In the Mie domain, the light scattering properties are closely related to the particle shape. To some extent, the oscillation amplitude, oscillation period and the central position of the extinction efficiency factor and scattering efficiency factor reflect the non-spherical feature of the ellipsoidal aerosol particles.