Hansen J E, Arking A
Science. 1971 Feb 19;171(3972):669-72. doi: 10.1126/science.171.3972.669.
The linear polarization of sunlight multiply scattered by the atmosphere, and cloud particles of Venus has been computed and compared with observations over the wavelength range from the ultraviolet to the infrared region. The following properties of the visible cloud layer are derived: the refractive index of the cloud particles is 1.45 +/- 0.02 at a wavelength of 0.55 micron, and there is an indication of a slight decrease in the value from the ultraviolet to the near-infrared region; the mean particle radius is very near 1 micron, and most of the particles are spherical; the cloud layer occurs high in the atmosphere where the pressure is about 50 millibars (equivalent to an altitude of approximately 20 kilometers on the earth). The results for the index of refraction eliminate the possibility that the visible clouds are composed of pure water or ice.
已对金星大气和云层粒子多次散射的太阳光线性偏振进行了计算，并与紫外到红外区域的观测结果进行了比较。由此得出了可见云层的以下特性：在波长0.55微米处，云层粒子的折射率为1.45±0.02，并且有迹象表明从紫外区域到近红外区域该值略有下降；平均粒子半径非常接近1微米，并且大多数粒子是球形的；云层出现在大气中压力约为50毫巴的高处（相当于地球上约20公里的高度）。折射率的结果排除了可见云由纯水或冰组成的可能性。
