Aerosol Impacts on Thunderstorm Electrification and Lightning Discharge over Houston

Lightning activity, a key indicator of the development of convective systems, can be significantly influenced by aerosols through complex microphysical and radiative interactions within thunderstorms. However, the precise physical processes in response to aerosol effects, particularly those related to storm charging and discharging remain highly uncertain from numerical modeling perspective. One reason for this uncertainty is the lack of comprehensive observations on evolutions of storm cloud electrification and discharge, which are needed to validate simulation results. In this study, we take advantage of fine-frequency, three-dimensional detections of storm charge structure from the Houston Lightning Mapping Array Network (HLMA), along with other measurements on aerosols and clouds, to constrain and thoroughly evaluate real-case simulations. The Weather Research and Forecast (WRF) with explicit electrification lightning scheme (WRF-ELEC) is employed to simulate several storm cases occurring over Houston, capturing variations in atmospheric dynamics and thermodynamics in which storms form. Modeling sensitivity experiments are conducted to reveal the process-level responses of cloud microphysics and dynamics to aerosols and their effects on storm charge. Our findings indicate that aerosols can modify storm charge structures, thereby altering lightning discharge characteristics. This enhanced understanding of the microphysical and electrification processes within thunderclouds deepens our knowledge of the role aerosols play in lightning generation, ultimately improving the prediction of lightning activity over metropolitan areas.