Light scattering by non-spherical particulates in the planetary atmosphere.

关于行星大气中球形粒子的光散射问题，有一个显式的解，称为米氏理论。然而，对于非球形粒子的光散射，目前尚无标准理论。在这项研究中，我们打算用近似的方法来研究大气中非球形粒子对光散射的影响，而不是寻求显式解。为了进行这项研究，我们经历了以下三个阶段；(1)收集了非球形粒子对光散射的实验数据，如Sassen和Liou（1979）对人工水冰云散射的实验室实验。然后，我们利用Pollack和Cuzzi（1980）提出的半经验理论得到了散射相函数。(2)其次，我们提出了一种新的辐射传递方程的离散坐标算法，该算法可以应用于非均匀行星大气层。(3)利用上述相位函数和算法，构建了基于地球摄影观测的火星白云光学厚度估算系统。奥林巴斯云、赫拉斯云和塔尔西斯晨云的光学厚度分别约为0.5、1.0和2.5-3.0。我们计划研究其他行星的大气热结构，考虑到大气中的非球形颗粒，如冰云和尘埃颗粒的热效应。

On the light scattering by the spherical particulates in the planetary atmosphere, there is an explicit solution called Mie theory. However, there is no standard theory for the light scattering by the non-spherical particulates. In this research, we intended to study the effects of the light scattering by the non-sphericsl particulates in the atmosphere using an approximate method instead of seeking the explicit solution.To do this research, we had the following three stages; (1) We collected the experimental data for the light scattering by the non-spherical particu1ates, such as the laboratory experiments on the scattering by artificial water ice clouds by Sassen and Liou (1979). Then, we obtained the scattering phase functions using a semi-empirical theory developed by Pollack and Cuzzi (1980). (2) Next, we have developed a new discrete-ordinate algorithm for the radiatve transfer equation, which can be applied to the non-homogeneous planetary atinosphere. (3) Using the above phase functions and algorithm, we have constructed a system to estimate the optical thickness of the Martian white clouds based on the earth-based photographic observations. The optical thickness of the Olympus cloud, Hellas cloud and Tharsis morning cloud are about 0.5, 1.0, and 2.5-3.0, respectively. We have plans to investigate the atmospheric thermal structures of the other planets allowing for the thermal effects of the non-spherical particulates such as, the ice clouds and dust particles in the atmosphere.