Study On Light Scattering And Transmission Characteristics Of Soot And Haze Aerosols Aggregation Particles

Atmospheric aerosols are an important part of the geogas system and a significant factor influencing aerosol climate and environmental effects.The scattering,absorption,extinction factors and asymmetry factors of aerosol particles are an important parameter for evaluation of the environmental pollution,research on climate radiation and transmission in the atmosphere of light.In this dissertation,Based on the basic theory of electromagnetic scattering,the research on the light scattering and transmission characteristics of soot and haze aerosols aggregation particles were carried out by numerical calculation method of electromagnetic scattering.A multi-component aerosol particle model was proposed,and the research on the light scattering and transmission characteristics of non-rotationally symmetric cluster aerosol particles are carried out.A multi-particle size aggregation particle system model was established to study the optical properties of multi-particle soot and haze aggregation particles with single component and internal and external mixed components.Using Monte Carlo method combined with improved HG* phase function,the multiple scattering and transmission properties of light in randomly distributed clusters of soot and haze are investigated.The new method of vector radiation transmission equation is derived theoretically,and further analyzed the vector radiation transmission characteristics of light in soot aerosol numerically.The basic physical characteristics of aerosol particles and the microphysical process of aerosol particle extinction characteristics were analyzed.The reliability of discrete dipole method for particle scattering problem was analyzed by Mie scattering theory.Numerically calculated the optical feature quantity of single shape soot aerosol particles,the results show that the wavelength of the incident light,the particle size,shape and whether or not the internal mixing are the main factors affecting the optical properties of the aerosol particles.The model of single particle size and multi-particle soot and haze aggregation particles was constructed.The optical properties of aerosol aggregation particles were studied by the numerical calculation method of particle light scattering.The results show that for single-component aggregation particles,the number and particle size of the original particles in the aggregation particles,the agglomeration process,the spatial structure,the pores and the composition of the aggregation particles are important factors for affecting the optical properties of the particles.Its optical properties also depend on the proportion of the various components in the aggregation particles.The improved HG* scattering phase function is proposed to study the transmission of light in aerosols.The numerical results of total reflectance and total transmittance as a function of transmission distance are given.The effects of particle type,shape,wavelength of incident light,angle of incidence and number density of particles in aerosol on transmission characteristics are analyzed.It is found that the improved HG* scattering phase function is suitable for the study of optical transmission characteristics in aerosols.The transmission characteristics of light in randomly distributed soot and haze were studied by the average equivalent method.It was found that the mixing ratio of particles in the aerosol,the size of the particles,the probability of particle distribution,the relative humidity in the haze and the visibility are the direct causes of the optical transmission characteristics.The Muller matrix of aerosol particles was studied.It is found that the angular distribution of the Muller matrix elements depends on the shape,size parameters,structure of the aggregation particles,and the proportion of different components in the aggregation particles.For aerosol aggregation particles in which the original particles of the same radius are aggregation,the value of the Muller scattering matrix element depends on the number of aggregation particles and the agglomeration process as well as the size parameters and spatial structure of the aggregation particles.The larger the size parameter,the stronger the forward scattering of the aerosol particles,and for the condensed particle system,the 16 elements of the Muller matrix are not zero.The Muller matrix is an important parameter in the vector radiation transmission mode.The accurate solution of the Muller matrix can lay the foundation for the study of vector radiation transmission characteristics in aerosols.Aiming at the application requirements of vector radiation transmission in aerosol,the new method of vector radiation transmission equation is derived theoretically.The vector radiation transmission characteristics of light in soot aerosol are numerically analyzed.The advantage of this method is that it starts from the vector radiation transfer equation itself.It can solve the Stokes vector of light at any point in a given model aerosol,which has certain application value for studying the polarization characteristics of light transmitted in aerosol.