Microphysical Responses to Cloud Seeding: Insights From Observation-Validated Simulations

Cloud seeding models are essential for understanding seeding mechanisms, yet their reliability remains insufficiently verified due to limited cases with confirmed seeding effects. On 19 March 2017, significant seeding signals were observed by multiple instruments following airborne cloud seeding over a stratiform cloud system with abundant supercooled water in northern China. This study performed an ensemble simulation of the case using two cloud microphysics schemes and three silver iodide (AgI) nucleation parameterizations, successfully replicating the vertical structure and evolution of the seeding-induced cloud. The simulated seeding impact area, precipitation intensity, and changes in raindrop spectra closely aligned with observations. Results indicate that cloud seeding increased ice crystal amounts primarily through the deposition nucleation of AgI particles, activated the auto-conversion of ice crystals to snow, enhanced snow deposition and riming processes, and ultimately increased surface precipitation through enhanced snow melting.