Numerical Simulation Research on the Effect of Ice Nucleation on Thundercloud Microphysical Process and Electrification

Based on an existing two-dimensional convective cloud model, this work adopts a nucleation scheme associated with aerosols to replace the original ice crystal nucleation empirical formula, and conducts a simulation contrast test on the two schemes.Simulation results show that:(1) The mass of ice crystals in the new scheme is mainly distributed in the -50.1℃ to -7.6℃ temperature region, higher than the original scheme's temperature region of -50.1℃ to -24.2℃.Throughout the thundercloud development process in the new scheme, the distribution height, temperature region, and maximum concentration value of ice crystals are greater than in the original scheme.(2) The new scheme produces a large number of ice crystals at relatively high temperature that dodge the water vapor and inhibit the growth of cloud droplets and rain.In addition, compared with the original scheme, graupel growth is greatly affected by the impact of raindrops and is dramatically reduced.This leads to the graupel being smaller than in the original scheme and to differences in its spatial distribution.(3) For thunderclouds, the early charge structure of the two schemes is different.The charge distribution area and amount of charge in the new scheme are greater than in the original scheme.In addition, the center heights of the main positive and the main negative charges differ at different times.This analysis of cloud microphysical process reveals the conditions favorable for researching the relationship between the thundercloud electrification process and the aerosol charge structure.