非偏振光在尘埃气溶胶中传输的多次散射特性

Multiple Scattering Characteristics of Unpolarized Light in Dustlike Aerosols

将具有不同横纵比的多分散、随机取向的椭球粒子混合,模拟了自然界中的尘埃粒子,利用T矩阵方法计算了其单次散射特性,并与球形粒子以及单一形状的椭球粒子模型进行了比较。结果表明,混合椭球粒子的相函数随角度分布是平滑、无特征的,且在侧散射方向上是平坦的,这与实验室和实地测量得到的真实尘埃粒子散射特性非常类似。利用此模型,根据矢量辐射传输理论,利用矢量累加法计算了尘埃气溶胶对非偏振光的多次散射特性,结果表明,利用任何单一形状的粒子模拟尘埃粒子的多次散射特性都会带来较大的误差。

We model the natural dustlike particles by using mixtures of polydisperse,randomly oriented spheroids with varying aspect ratios.The rigorous T-matrix method was used to compute the single scattering of dustlike aerosols,and the result was compared with the spherical particle and single shaped spheroids.The results show that the phase function averaged over a wide aspect-ratio distribution of spheroids is smooth,featureless,and flat at the side-scattering angle and closely resembles those natural dustlike particles.Based on the vector radiative transfer theory,the multiple scattering characteristics of unpolarized light in dustlike aerosols are computed by the vector adding method with this model,and the result indicates that significant errors will be caused with the application of any single shaped particles to compute the scattering characteristics of dustlike particles.