A numerical study of aerosol effects on electrification of thunderstorms

Numerical simulations are performed to investigate the effect of aerosol on microphysical and electrification in thunderstorm clouds. A two-dimensional (2-D) cumulus model with electrification scheme including non-inductive and inductive charge separation is used. The concentration of aerosol particles with distribution fitted by superimposing three log-normal distribution function rises from 50 to 10000 cm^-3. The results show that the charge structure in thundercloud keeps as a triple with aerosol concentration increasing. When aerosol concentration is changed from 50 to 1000 cm^-3, a stronger formation of cloud droplet, graupel and ice crystal result in increasing charge separation via non-inductive and inductive mechanism. However, in the range of 1000-3000 cm^-3, the decrease of ice crystal caused by vapor competition leads to the reduce of upper positive charge, while the enhance of graupel and cloud droplet result in the contribution of inductive charge to the middle and lower charge region increased with greater aerosol concentration. At very high aerosol concentration (above 3000 cm^-3),the magnitude of charge which remains steady in thundercloud is insensitive to aerosol concentration.