Angular-resolved light scattering by atmospheric ice particles - From single particle measurements to a global view of cirrus microphysics and radiative properties

在本项目中，将对KIT的云探测器PHIPS-HALO进行升级，在PHIPS-HALO已经具备的同时进行散射相函数测量和立体显微成像的基础上，实现对后半球单冰粒子的角分辨偏振测量。PHIPS-HALO/SID-3套件的新测量能力将在AIDA云模拟实验中进行全面测试和表征，以便在第一个资助期结束时可用于HALO测量。在北极和中纬度CIRRUS任务（2018/2019冬季）首次部署改进的HALO仪器包之前，这些实验室测量将提供新的和相关的冰粒子数据集，这些数据集将对粒子光散射和遥感社区具有重要价值。除了实验室测量外，改进的PHIPS-HALO仪器和PHIPS-HALO/SID-3包也将在其他机载平台上运行。凭借PHIPS-HALO/SID-3包的扩展能力，可以在未来的HALO任务中进行新的极化卫星观测验证。由于偏振测量对冰粒子的复杂性（形状复杂性和表面粗糙度）高度敏感，这样的验证任务可以帮助回答冰粒子复杂性是否是卷云的一个全局特征的问题。这个问题对于评估冰云的辐射影响是非常重要的。

Within this project, the cloud probe PHIPS-HALO of KIT will be upgraded in order to implement an angular-resolved polarization measurement of single ice particles in the rear hemisphere in addition to the simultaneous scattering phase function measurement and the stereo-microscopic imaging, which already exist on PHIPS-HALO. The new measurement capabilities of the PHIPS-HALO/SID-3 package will be comprehensively tested and characterized in AIDA cloud simulation experiments in order to have them available at the end of the first funding period for measurements on HALO. Well before the first deployment of the improved instrument package on HALO in the northern polar and mid-latitude CIRRUS mission (winter 2018/2019), these laboratory measurements will provide novel and relevant ice particle data sets that will be of great value for the particle light scattering and remote sensing communities. In addition to the laboratory measurements, the improved PHIPS-HALO instrument and the PHIPS-HALO/SID-3 package will be operated also on other airborne platforms. With the extended capabilities of the PHIPS-HALO/SID-3 package novel validations of polarimetric satellite observations can be conducted during future HALO missions. Since polarimetric measurements are highly sensitive to the ice particle complexity (shape complexity and surface roughness) such validation missions could help to answer the question whether ice particle complexity is a global feature of cirrus clouds. This question is of great importance for the assessment of the radiative impact of ice clouds.