大气粒子散射特性及其对空间偏振分布的影响

Scattering of Particles in the Atmosphere and their Influence on Celestial Polarization Patterns

利用米氏散射理论分析O2,N2,CO2,水滴和气溶胶等粒子的散射与偏振特性,通过随机传输理论仿真不同粒子影响下的偏振分布,并与检测结果进行比对,对粒子散射特性及其对空间偏振特性分布的影响进行了系统的理论研究。计算了不同粒子的散射系数和吸收系数随尺寸和复折射率的变化规律,研究了典型气态分子和非气态粒子偏振度及散射光强随散射角度的变化规律。通过检测结果与气态分子与非气态粒子影响下的模型之间的对比,得到空间中的偏振分布主要由气态分子决定,而地平附近中性点的出现与太阳高度角较低时刻偏振度的衰减与非气态粒子密切相关的结论。

Scattering and polarization properties of particles,such as O2,N2,CO2,water droplets and aerosol,were analyzed by the Mie scattering theory.The theoretical skylight polarization patterns were simulated with different particles and analyzed by making comparisons with real-time measured results.Systematic theoretical studies on the particle′s scattering and their influence on celestial polarization patterns were performed.The absorption and scattering coefficients of different particles were diagnosed with different sizes and complex refractive indices,also were the polarization degree and intensity with different scattering angles.Through the comparisons between measured results and theoretical models determined by gaseous and non-gaseous particles,the conclusion was got that the celestial skylight polarization patterns were mainly decided by gaseous particles while the appearance of neutral point near horizon and the attenuation of polarization degree at low sun elevation were induced by non-gaseous ones.