The effects of aerosol on development of thunderstorm electrification: A simulation study in Weather Research and Forecasting (WRF) model

The effects of aerosol on electrification of continental thunderstorm are simulated with WRF model coupled with electrification and activation scheme. Increasing aerosol concentration results in enhancement in electrification, due to more ice particles carried charge and greater mean charge separation amount per rebounding collision in polluted case. The charge structures change as the aerosol concentration increases. In clean case, the charge structure maintains the dipolar charge distribution through the simulation, while the charge structure of polluted case transforms form dipolarity at the initial stage of charging separation to inverted tripolarity after about 33 min. The signs of charge transferred to ice particles are determined by the rime accretion rate (RAR). If RAR is larger than the critical rime accretion rate (RAR_C), the graupel particles charge positively, and vice versa. In a word, increasing aerosol loading leads to increase in liquid water content resulting in a reversal charge structure that negative charge center develops above positive charge region.