| 利于上行负地闪始发的电荷区参数数值模拟 |
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| 引用本文： | 王艺儒,谭涌波,郑天雪,余骏皓,李春笋,刘敏芝.利于上行负地闪始发的电荷区参数数值模拟[J].应用气象学报,2020,31(2):175-184. |
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| 作者姓名： | 王艺儒 谭涌波 郑天雪 余骏皓 李春笋 刘敏芝 |
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| 作者单位： | 1.南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心/中国气象局气溶胶与云降水重点开放实验室, 南京 210044 |
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| 摘 要： | 在经典偶极性电荷结构下，结合已有的闪电放电参数化方案及中国气象局雷电野外科学试验基地的广州高建筑物雷电观测站(Tall-Object Lightning Observatory in Guangzhou，TOLOG)观测分析结果，不断调整主负电荷区参数进行二维高分辨率闪电模拟试验，讨论自持型上行负地闪与云中闪电之间的相互竞争关系以及有利于自持型上行负地闪始发的云中电荷结构。数值模拟结果表明:自持型上行负地闪始发与电荷结构存在一定关系，在主负电荷区越高的情况下，始发自持型上行负地闪需要的主负区电荷密度与电荷分布范围越大。对于不同类型的闪电始发条件，推测存在自持型上行负地闪始发的主负电荷区高度阈值，当主负电荷区高度高于该值时，随着主负区电荷量的不断累积，会始发起始于云中的闪电而不是自持型上行负地闪，当主负电荷区高度低于该值时，电荷的不断积累会导致自持型上行负地闪始发。
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| 关 键 词： | 上行负地闪 数值模拟 电荷结构 放电特征 |
| 收稿时间： | 2019-11-11 |
Numerical Simulation of Main Negative Charge Area Parameters for Upward Negative Cloud-to-ground Lightning |
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| Abstract: | Different types of lightning initiation condition are the focus of scientific research. The initiation of cloud lightning is competitive with self-sustaining uplink lightning. Based on the classical dipolar charge structure and the existing lightning discharge parameterization schemes, under the background of the classic dipolar charge structure, two-dimensional(2-D) high-resolution lightning discharge simulation experiments are carried out by adjusting the parameters of the main negative charge regions. Cloud charge structures which are beneficial to the onset of self-sustaining upward lightning are discussed. Results show that the part of the lightning at the beginning of the building has almost no bifurcation, and spreads straight toward the vertical direction. As the lightning continues developing, it gradually extends horizontally, and lightning channel branches gradually increase. Branches generally develop from bottom to top. The development of new branches in the front section of the main channel will hinder the development of lightning branches located to a certain extent. Branches at the same height may have a simultaneous developing trend. It can be inferred that this is related to the flat surface potential direction and the potential well in the charge region of the cloud. It is found that the higher the charge area is, the larger the charge density and distribution range the initial-self-sustaining uplink lightning needs. There speculates a threshold of the height of the main negative charge regions for the onset of upward lightning. When the negative charge region is higher than that, with the accumulation of charge in the main negative regions, the lightning will start in clouds instead of upward lightning. Only when the main negative area is lower than the threshold, the steady accumulation of electric charge will cause the flash originating. This may charge far away from the earth, and the cloud charge accumulation effects are greater than the increasing process of the electric field in the cloud for building sophisticated growth effects of electric field. As the main negative charge accumulates, the lightning starting conditions are firstly met in the cloud, initiating flashes in the clouds. |
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