介绍了一套同时工作在甚高频(very high frequency,VHF)和甚低频/低频(very-low/low frequency,VLF/LF)频段的三维闪电定位系统,并给出了初步观测结果。系统使用到达时间差法对2个频段的闪电辐射源进行定位,能连续地给出雷暴过程中闪电...介绍了一套同时工作在甚高频(very high frequency,VHF)和甚低频/低频(very-low/low frequency,VLF/LF)频段的三维闪电定位系统,并给出了初步观测结果。系统使用到达时间差法对2个频段的闪电辐射源进行定位,能连续地给出雷暴过程中闪电活动空间位置,并详细给出单次闪电的发展路径,在使用2个频段辐射波形参数进行定位的同时还可以保存原始波形用于深入研究。VHF、VLF/LF 2个频段闪电定位结果的时间分辨率分别为100?s和1ms,定位精度在站网覆盖范围可优于200m。2个频段的定位结果都能很好地描述雷暴中的闪电活动,但表现出的特征有一定差异。两频段定位结果对单个闪电发生路径进行描绘时,VLF/LF频段的大部分定位结果能与VHF定位结果重叠。展开更多
The three-dimensional temporal and spatial characteristics of VHF radiation events produced by light-ning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning map-...The three-dimensional temporal and spatial characteristics of VHF radiation events produced by light-ning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning map-ping array system with high time and space resolution. The results indicate that lightning hole (lighting free region) with about 5—6 km in diameter or lighting ring (annular lighting free region) is associated with the strong updraft in thunder-storm. The lasting time of lightning holes is either short or long, being about 20 min in a tornado-producing thunder-storm. The lightning holes appear before the occurrence of tornado. The lightning hole is the most obvious during the occurrence of tornado and some self-existent lighting radia-tion events appear at a height of 15—16 km. The lightning channels of inter-cloud (IC) lightning discharge exhibit clockwise rotary structures and do not have clear bilevel structures in the vicinity of the tornado. The lightning holes are corresponding to the strong updraft region. The tempo-ral and spatial distribution of lightning radiation events re-veals the structure of strong updraft in supercell thunder-storms. Positive cloud-to-ground (CG) lightning discharges dominate in these thunderstorms and the peak of positive CG lightning flash rate appears, with the maximum of 6 per minute, after or before the occurrence of tornado.展开更多
文摘介绍了一套同时工作在甚高频(very high frequency,VHF)和甚低频/低频(very-low/low frequency,VLF/LF)频段的三维闪电定位系统,并给出了初步观测结果。系统使用到达时间差法对2个频段的闪电辐射源进行定位,能连续地给出雷暴过程中闪电活动空间位置,并详细给出单次闪电的发展路径,在使用2个频段辐射波形参数进行定位的同时还可以保存原始波形用于深入研究。VHF、VLF/LF 2个频段闪电定位结果的时间分辨率分别为100?s和1ms,定位精度在站网覆盖范围可优于200m。2个频段的定位结果都能很好地描述雷暴中的闪电活动,但表现出的特征有一定差异。两频段定位结果对单个闪电发生路径进行描绘时,VLF/LF频段的大部分定位结果能与VHF定位结果重叠。
文摘The three-dimensional temporal and spatial characteristics of VHF radiation events produced by light-ning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning map-ping array system with high time and space resolution. The results indicate that lightning hole (lighting free region) with about 5—6 km in diameter or lighting ring (annular lighting free region) is associated with the strong updraft in thunder-storm. The lasting time of lightning holes is either short or long, being about 20 min in a tornado-producing thunder-storm. The lightning holes appear before the occurrence of tornado. The lightning hole is the most obvious during the occurrence of tornado and some self-existent lighting radia-tion events appear at a height of 15—16 km. The lightning channels of inter-cloud (IC) lightning discharge exhibit clockwise rotary structures and do not have clear bilevel structures in the vicinity of the tornado. The lightning holes are corresponding to the strong updraft region. The tempo-ral and spatial distribution of lightning radiation events re-veals the structure of strong updraft in supercell thunder-storms. Positive cloud-to-ground (CG) lightning discharges dominate in these thunderstorms and the peak of positive CG lightning flash rate appears, with the maximum of 6 per minute, after or before the occurrence of tornado.
