Characteristics of lightning radiation source distribution and charge structure of squall line
Characteristics of lightning radiation source distribution and charge structure of squall line
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DOI：
10.7498/aps.62.219201
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发表时间：
2013-08
影响因子：
1
通讯作者：
Dx Liu;X. Qie;Zc Wang;Xk Wu;Lx Pan
中科院分区：
文献类型：
--
作者：
Dx Liu;X. Qie;Zc Wang;Xk Wu;Lx Pan
闪电信息表明强对流的强度和发展。利用SAFIR3000闪电探测资料、多普勒天气雷达和降水资料，分析了2010年6月13日北京上空飑线的闪电活动和电荷结构特征。结果表明:飑线前部反射率较高的对流先导区闪电辐射源以闪电辐射源为主,层状区后部闪电辐射源数量仅在消散阶段逐渐增多。总闪电与对流降水的相关系数为0.82，云内闪电与对流降水的相关系数为0.76。据推测，闪电与飑线的动力和微物理过程密切相关。根据雷电辐射分布，讨论了飑线的电荷结构。飑线成熟阶段，闪电辐射源有两层，上层中心在11 km，下层中心在6 km。基于闪电传播的双向先导，并假设VHF源密度最大值最有可能与正电荷区域相关，得出飑线的特征为三极电荷结构，中间电荷区域位于8 km至10 km水平之间，两个正电荷区域分别位于距地面10至12 km和4至7 km水平处。
Lightning information indicates the intensity and the development of severe convection. The characteristics of lightning activity and charge structure of a squall line over Beijing on 13 June 2010 are analyzed by using the SAFIR3000 lightning detection data, Doppler weather radar and precipitation data. Results show that the lightning radiation sources are the major part in the convective leading region with a high reflectivity in front of the squall line, and the number of lightning radiation sources gradually increases in the back of stratiform region only at the dissipating stage. The correlation coefficient between the total lightning and convective precipitation is found to be 0.82, and that of intra-cloud lightning and convective precipitation is 0.76. It is inferred that the lightning is closely related to dynamical and microphysical processes of the squall line. According to the lightning radiation distribution, the charge structure of squall line is also discussed. At the mature stage of the squall line, the lightning radiation sources have two layers with the upper level centered at 11 km and the lower level at 6 km. Based on the bidirectional leader of lightning propagation and by assuming VHF source density maxima being most likely associated with the positive charge region, it is concluded that the squall line is characterized by a tripole charge structure with a middle charge region between the levels of 8 km and 10 km, and the two positive charge regions at the levels of 10 to 12 km and 4 to 7 km above the ground, respectively.