Plass G N, Kattawar G W
Appl Opt. 1971 Oct 1;10(10):2304-10. doi: 10.1364/AO.10.002304.
The reflection of light pulses from clouds is calculated by a Monte Carlo technique for all orders of multiple scattering. The photons are emitted within a narrow cone, scattered by water droplets and ice crystals in clouds as well as by Rayleigh scattering centers and aerosols, and finally detected at the source position. The returned flux is determined as a function of the photon path length for: (1) three different size distributions for the cloud particles (haze C, nimbostratus, ice crystal); (2) two different variations of the number density with height of the scattering centers within the cloud; (3) six different zenith angles of the source. The influence of detector half-width and of the atmosphere on the returned flux is studied. The returned flux as a function of the photon path length depends on both the size distribution of the particles within the cloud and on the density of scattering centers as a function of height.
利用蒙特卡罗技术计算了光脉冲在云层中的多次散射各阶反射情况。光子在一个狭窄的圆锥内发射，在云层中被水滴和冰晶以及瑞利散射中心和气溶胶散射，最终在源位置被探测到。返回通量被确定为光子路径长度的函数，针对以下情况：（1）云粒子的三种不同尺寸分布（霾C、雨层云、冰晶）；（2）云层内散射中心数量密度随高度的两种不同变化；（3）源的六个不同天顶角。研究了探测器半宽度和大气对返回通量的影响。作为光子路径长度函数的返回通量既取决于云层内粒子的尺寸分布，也取决于散射中心密度随高度的变化。
