Variation of deposited charge in intracloud lightning: A modeling study with self-sustained neutral charge parameterization

The characteristics of charge in lightning channel are the focus of lightning physics research, yet it is difficult to directly obtain detailed evolution characteristics of charge in the channel using existing observation methods. In order to further study the variation characteristics of charge in lightning channel and complement the lightning detection technology, it is necessary to carry out model work. Using the Self-Sustained Charge Neutrality Intracloud Lightning Parameterization model, multiple intracloud flashes are simulated under the three-pole charge background and a typical case is selected. The variation characteristics of channel charge and their influencing factors are analyzed. The results are as follows: A certain amount of positive or negative polarity initial charge will deposit in the channels when these leader channels first form. When the subsequent branch extends, the previous channel will deposit heteropolar charges from the subsequent branches, and the charge of the initial polarity in the channel will be continuously neutralized, while the polarity of some channels may change. The charge in the channel will not change if the channel has decayed or its subsequent branches stop extending. When the re-breakdown process occurs, the heteropolar charge in the cut-off channel will be significantly reduced, and the heteropolar charge in the reactivated channel will be significantly increased. The research shows that the charge variation in the leader channel is related to the state of the channel itself and the extension of the subsequent branches. The amplitude of charge change in the channel is positively correlated with the initial charge and the activity of subsequent branches, and the initial charge is positively correlated with the first breakdown electric field. In addition, under the influence of polarity asymmetry between positive and negative leaders, the initial point of intracloud lightning tends to deposit more positive charges.