| 云闪放电对云内电荷和电位分布影响的数值模拟 |
| |
| 引用本文： | 谭涌波,陶善昌,祝宝友,马明,吕伟涛.云闪放电对云内电荷和电位分布影响的数值模拟[J].地球物理学报,2007,50(4):1053-1065. |
| |
| 作者姓名： | 谭涌波 陶善昌 祝宝友 马明 吕伟涛 |
| |
| 作者单位： | 1.中国科学技术大学地球和空间科学学院，合肥 2300262 中国气象科学研究院，北京100081 |
| |
| 基金项目： | 国家自然科学基金项目(40205002,40475004)资助. |
| |
| 摘 要： | 我们应用改进的随机闪电参数化方案，对两次雷暴的起、放电过程进行了二维125 m和250 m分辨率云闪模拟试验，分析表明高分辨率模拟的云闪通道几何结构、延伸范围和最大垂直电场变化等特征与观测结果更为一致，并且揭示了云闪放电重新配置云内电荷分布和空间电荷中和过程的一种新的物理图像：(1) 云闪的直接物理效应是在已有的空间电荷区内沿着放电通道沉积异极性电荷、形成复杂的空间电荷分布，有效地导致云中电位和场强绝对值及静电场能量剧烈下降，使放电终止.其中：放电后在闪电通道经过主要区域，电位降到±30 MV之间，垂直电场强度也降到±20 kV·m-1之间，一次正或负云闪估计消耗掉107～1010 J静电能；(2) 云中电荷中和不是正、负空间电荷简单地直接相互抵消的瞬态过程，而是广泛分布的云中空间电荷与通道沉积的异极性电荷通过湍流交换、平流输送、重力沉降以及起电等多种因素逐渐混合并部分被中和的一个后续慢过程，其弛豫时间典型值在14～44 s之间，在此期间通道感应电荷总量下降到50%以下.并残余部分电荷参与后续放电前高空间电荷密度和强电场的重建过程.
|
| 关 键 词： | 云闪 感应电荷 电位分布变化 静电能量变化 电荷中和 |
| 文章编号： | 0001-5733（2007）04-1053-13 |
| 收稿时间： | 2006-6-29 |
| 修稿时间： | 2006-06-29 |
A simulation of the effects of intra-cloud lightning discharges on the charges and electrostatic potential distributions in a thundercloud |
| |
| TAN Yong-Bo,TAO Shan-Chang,ZHU Bao-You,MA Ming,L Wei-Tao.A simulation of the effects of intra-cloud lightning discharges on the charges and electrostatic potential distributions in a thundercloud[J].Chinese Journal of Geophysics,2007,50(4):1053-1065. |
| |
| Authors: | TAN Yong-Bo TAO Shan-Chang ZHU Bao-You MA Ming L Wei-Tao |
| |
| Institution: | 1.School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China 2 Chinese Academy of Meteorological Sciences, Beijing 100081, China |
| |
| Abstract: | This paper extends the use of Stochastic Lightning Model in a simulation experiment, in which 125 and 250 m resolution simulations of intra_cloud(IC) lightning discharges within a two dimensional numerical thunderstorm model have been performed, and gives the comparing analyses of the simulated results with the observed data. The results show: (1) During an IC flash discharge, more complex distribution of the space charges in thundercloud is caused by the induced charges along the channels, and lead to a sudden decrease in the maxima of electrostatic potential and potential gradient as well as consume of electrostatic energy of thundercloud. The ratio of induced charges to surrounding space charges varies from 02% to 708%, the electrostatic potential and field strength drop down respectively to ±30 MV and ±20 kV·m-1 where the flash channels passed, and consumed electrostatic energy of thunderstorm for a positive or negative IC flash is about 107～1010 J. (2) As contrasted with transient IC discharges, the charge neutralization in thundercloud is a slow process with a relaxation time of about one minute or less. The dispersed space charges in thundercloud and opposite charges deposited in the flash channels are mixed slowly and neutralized partially by turbulence exchanging, advection transporting and gravitational sedimentation etc.. There are 15%～40% excess of induced channel charges to be not neutralized, which contributes to rebuilding new distribution of space charges and electrostatic potential. |
| |
| Keywords: | Intra-cloud flash Induced charge Variation of potential distribution Variation of electrostatic energy Charge neutralization |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
