| Based on wave radiation transmission theory in random medium and Monte Carlo numerical simulation method, the transmission characteristic of the laser in aerosol in different situations is studied. Main tasks are as follows:1. Based on Mie theory, the single scattering properties of spherical and multi-layer spherical particles are calculated. The scattering intensity of the convolute symmetric non-spherical particles in different size, shape, and the wavelength is calculated under the use of diffuse transmission matrix method. Besides, the influence of relative location, the radius and the number of elementary particles on the scattering intensity of clusters are analyzed by Generalized Multi-particle Mie (GMM).2. The influence of the optical thickness on the transmission of the lognormal distributed water fog is calculated by using the improved Monte Carlo method with the particle size distribution in consideration. The transmission characteristics of the urban aerosol external mixed by the water-soluble aerosols, dust and soot are discussed considering the types of particles, and it is compared with literature data. The extinction characteristics of aerosol internal mixed by water and graphite changed with component percent and wavelength are investigated, adopting the multi-layer concentric sphere model.3. Phase function of non-spherical particles is fitted by random probability sampling method, and it is compared with the Henyey-Greenstein ( H ? G) empirical formula. The result showed that the root-mean-square of Phase function fitted by random probability sampling method is smaller. The influence of sampling frequency and sampling interval of scattering angle on the fitted results is also discussed.4. The transmission characteristics of aerosol composed with discrete random distributed convolute symmetric non-spherical particles are discussed. Take oceanic elliptical aerosol as an example,the computing time is shorten by using the scattering phase function database. The transmissions calculated separately by scattering phase function sampling methods, H ? Gphase function and Four-Flux method are compared. The influence of multiple scattering on the relative error of transmittance is discussed. 5. The transmission characteristics of aerosol composed with discrete random distributed non-spherical particles are discussed. Take soot aerosol as an example, the method of establishing scattering phase function database for scattering angle and azimuth angle sampling is studied. The dependence of the radius and the number of elementary particles, incident wavelength on the time of establishing database is analyzed. Factors affecting the transmission characteristics of clusters aerosol are discussed. The results show that the influence of the fitted method of phase function on the transmission characteristics is significant. For the transmission characteristics of non-spherical particle aerosol, using H ? G phase function method for spherical particles by volume equivalence or area equivalence will lead to large errors. It is very important to calculate the transmission characteristics of aerosol using improved Monte Carlo method in the case of multiple scattering.
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