Distinct Change of Supercooled Liquid Cloud Properties by Aerosols From an Aircraft-Based Seeding Experiment

Cloud plays essential roles to Earth's energy balance and hydrological cycle. Its characteristics could be modified by human activities through cloud seeding. However, there is long-lasting debate whether the cloud seeding can modify the clouds to introduce or change precipitation effectively, due to the challenge that the effect of cloud seeding is difficult to be evaluated. Using the data from a cloud seeding experiment, this study investigates the differences of cloud properties between before and after the cloud seeding for a supercooled liquid cloud. It shows that before the cloud seeding, the clouds are supercooled liquid phase clouds. After cloud seeding, the observations from both the cloud particle images and cloud particle size distributions indicate the occurrence of large ice crystal particles and the broadening of particle size distribution. Thus, much larger and much more ice crystal particles occurred after the cloud seeding, which could further grow into precipitation particles through collision-coalescence process. Satellite image further shows the formation of precipitation clearly after the cloud seeding experiment. This study suggests that cloud seeding can work efficiently for supercooled liquid clouds.