Analysis Of Polarization Characteristics Of Light Scattering By T-matrix Method For Typical Smog Particle Model

In smog weather,natural light produces polarized light after being scattered with smog particles during transmission in the atmosphere.The polarized light carries a series of polarization information of smog particles,including the size parameters,particle morphology,scale distribution,complex refractive index and other physical characteristics of smog particles.Researching the light scattering of smog particles has important significance to the formation mechanism,source and to establish a better atmospheric model.In this thesis,based on the T matrix method,the light scattering polarization ch aracteristics of a single spherical,non-spherical(ellipsoidal,cylindrical)smog particle are simulated.The spherical particles mainly analyze the influence of particle radius and complex refractive index on the light scattering polarization characteristics of the particles.The non-spherical particles are mainly analyzed from the effective radius,axial ratio and complex refractive index of the particles to the light scattering polarization characteristics of the particles.The analysis results show that the spherical particles are forward-scattered,and the larger particle radius is,the larger value of the degree of linear polarization is in the backscattering,the larger particle radius is,the smaller value of the degree of linear polarization is.The larger effective radius of the non-spherical particles is,the greater degree of linear polarization is.The value of the degree of circular polarization is inversely proportional to the size of the particle radius.When the value of the degree of non-spherical is smaller,the value of the degree of linear polarization and the degree of circular polarization is larger.By analysis of the polarization characteristics of sulfuric acid particles,ammonium sulfate particles,ammonium nitrate particles,dust particles and carbonaceous aerosol particles with different complex refractive indices,it shows that the larger complex refractive index is,the greater influence on the polarization characteristics of the particles isBased on Mie scattering theory and T-matrix method,the effects of radius range and complex refractive index of particles on the scattering polarization characteristics of spherical particles are studied,and the simulation analysis of five types of spherical particles mixed in uniform proportion is carried out.The results show that the larger radius range of particles is,the larger degree of linear polarization is,and the smaller value of the degree of circular polarization is.For five types of single-system particles,the degree of linear polarization of carbon aerosol particles is greater than other types of particles,the degree of linear polarization of carbon aerosol particles with larger complex refractive index is greater than zero,but the degree of circular polarization of carbon aerosol particles is smaller than other types of particles The degree of linear polarization of mixed spherical particles firstly decreases and then increases with the increase of scattering angle,and the degree of circular polarization decreases with the increase of scattering angle.