Dust Aerosol Effects on Charge Structure and Lightning Activity of a Continental Thunderstorm: A Modeling Study With Thompson‐Electrification Scheme

Abstract A mesoscale electrification‐coupled model was established within the WRF model by integrating with the Thompson microphysics scheme. Based on the Thompson‐electrification scheme and MERRA‐2 aerosol reanalysis data, this study investigated the individual and synergistic impacts of dust aerosols acting as cloud condensation nuclei (cloud condensation nuclei (CCN)) and ice nuclei (IN) on microphysics, charge structures and lightning activity of a rare dust‐associated continental thunderstorm. By four sensitivity experiments, the results demonstrated that elevated CCN concentrations increased the mass content and number concentrations of cloud droplets, whereas high IN significantly amplified ice crystal and snow aggregates concentrations. Combined CCN and IN effects synergistically intensified hydrometeor modifications, the polarity reversal threshold for non‐inductive charging by increasing mixed‐phase liquid water content is lowered with increased CCN, and the charge separation efficiency through ice‐graupel collisions is increased by high IN. Under the influence of dust aerosol, the lower positive charge region is strengthened by CCN enhancement and main charge layer densities are intensified by IN increasing. The charge structure of thunderstorm demonstrated a classical tripole under dust free circumstance, converted to quadrupolar configurations with high dust aerosol increasing, which facilitated +CG lightning generation. In addition, under high CCN concentrations, total cloud‐to‐ground (CG) lightning frequency decreased but the positive CG (+CG) proportion increased, while both CG frequency and +CG proportion increased with high IN concentration, resulting in a maximum prevalence of +CG lightning.