Abstract:
Aiming at further comprehending the effect of updrafts on the complex charge structure characteristics in thunderstorm clouds, the WRF (Weather Research and Forecasting) model with an electrification and discharge parameterization scheme is employed to simulate the process of a strong thunderstorm with an inverted charge structure that was reported on 6 June 2012, in the Deep Convective Clouds and Chemistry (DC3) experiment. The results demonstrate that the electrification region corresponds to the strong echo region, which mainly occurs in the ice–water mixing region with cloud water mixing ratios exceeding 0.2 g kg
−1 in the updraft region. The noninductive electrification mechanism dominates the electrification process in thunderstorm clouds. There is a considerable amount of charged particles in the periphery area of the updraft, which is mainly formed by airflow-induced backward horizontal transport of charged particles from the electrified area. The polarity of homogeneous particles slightly changes in a large range, but the net charge distribution becomes more complex because of the different contents and charges of the particles. An updraft with a certain intensity can destroy the continuity of the electrified area, resulting in a high-density, smaller area with positive and negative staggered distribution in the convection region. Because there is no updraft in the stratiform area, the charged particles in this area mainly originate from the horizontal transport in the updraft region; therefore, in the stratiform cloud area, the charge structure is relatively continuous and wide, but the charge density is relatively weak. Because of the different intensities and inclination degrees of updraft in different cell life periods, there exist certain differences in the distribution of hydrometeor particles between cells, making the reversal temperature and electrification rate of the particles notably different from each other. Therefore, during cell merging, the electrified area in the updraft region becomes more fragmented, and the charge structure becomes more complex.