H. Cai, Xiaolei Wang, Gang Liu, M. Liao, Shangmao Hu, Yu Liu
{"title":"两道自然闪电击中广州塔时不同寻常的闪电龙头的高速视频观测","authors":"H. Cai, Xiaolei Wang, Gang Liu, M. Liao, Shangmao Hu, Yu Liu","doi":"10.1109/ICLPandSIPDA54065.2021.9627448","DOIUrl":null,"url":null,"abstract":"Dart leader behavior preceding eight subsequent return strokes (RS) in two negative cloud-to-ground (CG) lightning flashes striking on the top of Canton tower has been investigated, by using the high-speed video camera. The optical observations show some unusual behavior of dart leader propagation. There appear two branches on the top portion of discharge channel in one flash. Dart leader could propagate downward along either branch, and after RS initiation, there occurs a tiny leader branch near the branching point, following the other branch but normally does not propagate long. Only in one subsequent stoke event, it keeps developing upward so that the entire branched channel can be apparently observed. In the other flash, one dart leader, whose leader tip has the similar characteristics as the normal dart leader, is initiated from the striking point and then develops upward, along the preconditioned channel. The two-dimensional (2-D) average speed of dart leader propagation ranges from 2.83×106 m/s to 1.92×107 m/s, mostly in the order of 106m/s.","PeriodicalId":70714,"journal":{"name":"中国防雷","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"High-speed Video Observations of Unusual Dart Leaders in Two Natural Lightning Flashes Striking on Canton Tower\",\"authors\":\"H. Cai, Xiaolei Wang, Gang Liu, M. Liao, Shangmao Hu, Yu Liu\",\"doi\":\"10.1109/ICLPandSIPDA54065.2021.9627448\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Dart leader behavior preceding eight subsequent return strokes (RS) in two negative cloud-to-ground (CG) lightning flashes striking on the top of Canton tower has been investigated, by using the high-speed video camera. The optical observations show some unusual behavior of dart leader propagation. There appear two branches on the top portion of discharge channel in one flash. Dart leader could propagate downward along either branch, and after RS initiation, there occurs a tiny leader branch near the branching point, following the other branch but normally does not propagate long. Only in one subsequent stoke event, it keeps developing upward so that the entire branched channel can be apparently observed. In the other flash, one dart leader, whose leader tip has the similar characteristics as the normal dart leader, is initiated from the striking point and then develops upward, along the preconditioned channel. The two-dimensional (2-D) average speed of dart leader propagation ranges from 2.83×106 m/s to 1.92×107 m/s, mostly in the order of 106m/s.\",\"PeriodicalId\":70714,\"journal\":{\"name\":\"中国防雷\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2021-09-20\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"中国防雷\",\"FirstCategoryId\":\"1089\",\"ListUrlMain\":\"https://doi.org/10.1109/ICLPandSIPDA54065.2021.9627448\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"中国防雷","FirstCategoryId":"1089","ListUrlMain":"https://doi.org/10.1109/ICLPandSIPDA54065.2021.9627448","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
利用高速摄像机研究了两次云对地负闪电击中广州塔顶后8次回击前的镖头行为。光学观察显示出一些不寻常的省道前导传播行为。在一次闪光中,放电通道顶部出现两个支路。先导子可沿任一分支向下传播,RS起始后,在分支点附近出现一个微小的先导子分支,跟随另一个分支,但通常不长时间传播。只有在随后的一个斯托克事件中,它继续向上发展,以便可以明显地观察到整个分支通道。在另一闪中,其尖端特征与正常省道相似的一个省道从击打点开始,然后沿着预设通道向上发展。镖头的二维(2-D)平均传播速度在2.83×106 m/s ~ 1.92×107 m/s之间,以106m/s居多。
High-speed Video Observations of Unusual Dart Leaders in Two Natural Lightning Flashes Striking on Canton Tower
Dart leader behavior preceding eight subsequent return strokes (RS) in two negative cloud-to-ground (CG) lightning flashes striking on the top of Canton tower has been investigated, by using the high-speed video camera. The optical observations show some unusual behavior of dart leader propagation. There appear two branches on the top portion of discharge channel in one flash. Dart leader could propagate downward along either branch, and after RS initiation, there occurs a tiny leader branch near the branching point, following the other branch but normally does not propagate long. Only in one subsequent stoke event, it keeps developing upward so that the entire branched channel can be apparently observed. In the other flash, one dart leader, whose leader tip has the similar characteristics as the normal dart leader, is initiated from the striking point and then develops upward, along the preconditioned channel. The two-dimensional (2-D) average speed of dart leader propagation ranges from 2.83×106 m/s to 1.92×107 m/s, mostly in the order of 106m/s.