求解非球形大粒子光散射问题的一种简明数值计算方法

A SUCCINCT NUMERICAL METHOD TO SOLVE THE SCATTERING PROBLEM OF LARGE NOSPHERICAL PARTICLES

对于实际大气中传输的非偏振自然光的散射问题,所关心的散射参量通常为散射强度和线偏振度。本文通过对光子沿随机抽样人射路径的散射几率进行统计,建立了计算多粒径大粒子系统单次散射相函数及线偏振度的一种简明数值方法。对于粒子表面具有曲率的情况,该方法可以避免处理由表面曲率引入的“发散因子”。由于大气中液滴的形状一般近似为旋转扁椭球,本文也根据所建立的数值计算方法,计算和讨论了旋转扁椭球形液滴的散射相函数和线偏振度。

For the scattering of unpolarized natural light transfering in real atmosphere, the scattering parameters about which we are concerned are usually the intensity of scattered light and degree of linear polarization. In this paper, based upon the statistics about the scattering probability of photons along randomly sampled incident routes, a succinct numerical method has been developed to compute the phase function and degree of polarization for the single scattering of light by polydispersive large particles. The difficulty related to divergence, when the surface of scattering particle is curved, has been avoided by this numerical method. Meanwhile, because the shapes of water droplet in atmosphere are often spheroids approximatively, the scattering characteristics of spheroidal water droplets have also been discussed.