非球形气溶胶对光波传输特性的影响

为分析非球形气溶胶对光波传输特性的影响,依据非球形气溶胶相函数的变化特征,提出了相函数分段加权采样方案,改进了Monte Carlo模型中散射角抽样方法,并验证了其有效性。采用T矩阵法模拟了非球形气溶胶散射特性,讨论了0.55μm光波透过率、反射率随气溶胶形状、传播距离的变化规律,将结果与H-G相函数抽样方案的模拟结果进行了比较。结果表明,相函数分段加权采样方案可显著减小散射角抽样误差与相函数抽样偏差;粒子形状对透过率与反射率影响显著,且传播距离越长,影响越大,形状对反射率影响强于透射率;与H-G相函数抽样方案模拟结果相比,本模型模拟的光波透过率偏大,反射率偏小。

Effect of non-spherical aerosol on light propagation properties

To take a look at the effect of non-spherical aerosol on light propagation properties, the scattering angle sampling method in the Monte Carlo model was improved by a phase function sectional-weighted sampling method, with its accuracy and feasibility validated subsequently. T-matrix method was applied to simulating the scattering properties of non-spherical aerosols. Variation of transmittance and reflectance with particle shapes and propagation distance was discussed by the improved model. Comparison was made between the results of our method and those of the traditional one, in which H-G formula was applied to randomly sampling the scattering angle. Simulation results show that phase function sectional-weighted sampling method could remarkably decrease the sampling errors of scattering angle, proving that our method is effective. Transmittance and reflectance of aerosol layer is significantly affected by particle shapes, and the influence of shapes on reflectance is much stronger than that on transmittance. Besides, with propagation distance increasing, the influence of shape becomes more and more obvious. Compared with the results of the traditional Monte Carlo model, transmittance calculated by our model is relatively larger, while reflectance is underestimated.