云相态识别是云参数研究的重要组成部分,为了有效识别水云和冰云,根据水云和冰云微物理性质的差别,研究了水云和冰云的单次散射特性,采用基于倍加累加法的矢量辐射传输方程模拟了水云和冰云的多角度偏振特性。模拟结果表明,光谱的多角度偏振特性能够体现出水云粒子和冰云粒子微物理性质的差异,云在特定方向反射的偏振辐射强度对云相态非常敏感,可以用来进行云相态的识别。在模拟的基础上进行了云相态识别算法的研究,并利用多角度偏振卫星数据——POLDER 0.865 μm通道数据进行了实例分析。识别结果与MODIS云相态产品及其1.38 μm卷云检测结果进行了比较。分析结果表明,基于多角度偏振特性云相态识别算法可以有效地进行云相态识别。

Cloud phase recognition is important for cloud studies. The single-scattering properties of water cloud and ice cloud were studied to effectively identify them, in the light of the difference of microphysical characteristics between the two kinds of clouds, their polarized radiance was simulated by utilizing the vector radiative transfer equation based on adding-doubling method. The results indicate that the polarized radiance over a large range of scattering angles can show the distinction between water cloud and ice cloud, and can be used to recognize the cloud phase. The algorithm of cloud phase classification based on the simulations is presented and demonstrated by using the data of POLDER 0.865 μm. The results of cloud phase retrieval was compared with the phase products of MODIS and the result of cirrus detection of MODIS based on 1.38 μm. The analysis shows that the cloud phase retrieval method based on near-infrared polarimetric measurements can improve the capability of cloud phase classification through satellites.