Ensemble Modeling of Cloud Seeding with Multiple Microphysics Schemes

To quantify microphysics-related uncertainties in cloud seeding modeling, parameterizations of silver iodide ice nucleation were implemented as a standalone physics module in the Weather Research and Forecasting (WRF) model. The module is compatible with most bulk microphysics schemes, enabling ensemble cloud seeding simulations using multiple microphysics schemes. Twin ensemble forecast experiments—a control (unseeded) and a seeded ensemble—were conducted for a post-frontal stratiform snowfall event in central China. The control ensemble reproduced the observed precipitation pattern, while the seeded ensemble predicted predominantly positive precipitation enhancement over the target area.

Both ensembles employed multiple initial and lateral boundary conditions (IC/LBCs) and microphysics schemes to assess their respective contributions to uncertainties. For the control ensemble, IC/LBCs and microphysics schemes exerted comparable overall influences on the variability of supercooled liquid water and precipitation. IC/LBCs primarily affected the spatial distribution of precipitation, whereas microphysics schemes had a stronger influence on intensity. For the seeded ensemble, microphysics schemes dominated the uncertainty in cloud-seeding-induced changes in microphysical properties and precipitation. These results underscore the importance of incorporating multiple microphysics schemes in ensemble cloud seeding modeling to robustly represent uncertainty.