球形雾霾粒子的紫外光散射偏振特性研究

在我国经济社会快速发展的同时，雾霾天气成为了突出的环境问题，雾霾粒子的测量非常重要。偏振紫外光与大气雾霾粒子发生散射后，散射光偏振状态(Stokes矢量以及偏振度)的改变能反映雾霾粒子的相关物理特性(粒径、复杂折射率等)。基于Mie散射理论建立了紫外光雾霾球形粒子直视和非直视单次散射模型，研究了单个球形粒子和链状结构球形粒子物理特性的改变对散射光偏振状态的影响，并用蒙特卡洛仿真分析已知粒径分布的雾霾粒子浓度对散射光偏振状态的影响。结果表明：针对单个球形粒子，随着粒子粒径的增大Stokes矢量中散射光光强(I_s)随之增强，粒子复折射率虚部为先增大后较小，偏振度也是在不断增大，且复折射率虚部较小时，偏振度增加趋势快;对于粒径分布不变的雾霾粒子，随着粒子的浓度增加，雾霾粒子的散射系数、消光系数和吸收系数均呈线性增加，但是I_s先增大后减小。针对链状球形粒子，随着粒子个数的增加，I_s均呈现增大的趋势，且偏振度可用于区分链状球形粒子是否由相同球形粒子组成; 相同球形粒子组成链状结构中，I_s随着粒子数量的增加而线性增大，偏振度不改变;不同球形粒子组成的链状结构，I_s以及偏振度的变化趋势可以区分粒子物理特性。

The Study of UV Scattering Polarization Properties of Spherical Particles of Haze

With the rapid development of economy and society in our country,atmospheric haze has become a prominent environmental issue .Measuring haze particles is also important .Polarized ultraviolet light is scattered by atmospheric haze particles,the changes of scattered light polarization state(Stokes vector and the degree of polarization) in atmospheric haze can reflect the physical properties of the particles (particle size and the complex refractive index,etc .) .Based on Mie scattering theory,line-of-sight and non-line-of-sight of a single UV scattering model is established .On one hand,the effects of the physical properties of the single and chain-structure spherical p articles for the UV light polarization properties are studied .On the other hand,based on Monte Carlo Simulation,the impacts of haze particle concentration on polarization state at a fixed particle size distribution are discussed .The simulation results show that: with the particle size of single spherical increasing,the scattered light intensity in Stokes vector (Is) is significantly enhanced .Is shows a trend of first increase then decrease with the increase of the complex refractive index's imaginary part .The degree of polarization is constantly in creasing with the increase of the complex refractive index's imaginary part and t he imaginary part of the complex refractive index is small,the degree of polarization trend of fast increase .With the concentration of particles in haze increasing when the distribution of particle size is a fixed value,haze particles scattering coefficient,extinction coefficient and absorption coefficient showed a linear increase,while Is is reduced after the first increases .For chain-structure spherical particles,with the increase of the number of particles,Is shows a tendency to increase .As the same time,degrees of polarization distinguish whether the chain-structure spherical particles are made up by the same spherical particle .In the chain-structure consisted of same spherical particles,Is increases linearly with the increase of the number of particles and the degree of polarization does not change .The Is under the chain-structure consisted of different spherical particles can distinguish particles' physical properties according to the changing trend of scattering light polarization state .