Simulation of electrified storms with comparison of the charge structure and lightning efficiency

Abstract

An electrification and lightning flash scheme was run in a cloud‐resolving model to study the electrical structure of idealized convective storms with several charge separation parameterizations. The electrification of an intense multicellular storm was first simulated. The results confirm the sensitivity of the cloud polarity and lightning flash characteristics to three noninductive charging formulations. Furthermore, it is found that the inductive charging is an efficient mechanism to enhance the lower electric charge, which favors cloud‐to‐ground flashes. Then, microphysical and electrical budgets were calculated for the convective and stratiform regions of a two‐dimensional squall line. The simulation shows that the liquid water content is high enough to generate graupel by riming. Thus the noninductive separation process is efficient to charge the stratiform plume as well, and lightning flashes can be triggered. Finally, the application of various noninductive charging schemes to several convective storms showed the storm electrification variability, which heavily depends on the cloud dynamics and microphysics. The study reveals some remarkable features concerning the charge structure and the cloud‐to‐ground flash polarity.