A Framework for Modeling Aerosol‐Cloud‐Lightning Interactions: Validation of Charge Structure and Aerosol Effects

This study develops a novel framework within the Weather Research and Forecast Model for modeling aerosol‐cloud‐lightning interactions. The framework explicitly represent aerosol‐cloud interactions by prescribing aerosols with two configurations: an idealized setup, where both cloud condensation nuclei (CCN) and ice nucleating particles (IN) are assumed to have a single chemical composition and spatially uniform distributions; and a quasi‐realistic configuration, with multi‐species aerosols assigned spatially varying distributions, where hygroscopic components act as CCN, dust particles act as IN, and all aerosol species influence radiative transfer. Cloud microphysics is coupled with detailed charge‐to‐discharge processes to simulate lightning. The framework is evaluated using two thunderstorms in Guangdong, China. For an isolated storm, the model reproduces a tripolar charge structure similar to observations, demonstrating its capability in simulating electrification. For a frontal storm, the model reproduces the observed precipitation, and lightning is broadly simulated in the correct regions of the storm but substantially underestimated. This requires further investigation. The results further show that increasing CCN concentration suppresses rainfall while enhancing lightning. Higher CCN concentrations produce more numerous but smaller cloud droplets, which suppresses the coalescence into rain, allows more droplets to loft into the upper level, and forms more but smaller cloud ice particles. This boosts graupel‐ice collisions, intensifies non‐inductive charging, strengthens the upper positive charge and the vertical electric‐field gradient, ultimately increasing the lightning frequency. In contrast, no significant aerosol‐induced updraft invigoration is observed. These results suggest that microphysical effects may dominate the dynamical invigoration effect in aerosol modulating thunderstorm electrification and lightning.