Scattering pattern of lightning‐induced ionospheric disturbances associated with early/fast VLF events
Scattering pattern of lightning‐induced ionospheric disturbances associated with early/fast VLF events
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与早期/快速 VLF 事件相关的闪电引起的电离层扰动的散射模式
DOI：
10.1029/1999gl900521
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发表时间：
1999
影响因子：
5.2
通讯作者：
T. Bell
中科院分区：
文献类型：
--
作者：
M. P. Johnson;U. Inan;S. Lev;T. Bell
在九个相距较近（约65公里）的地点同时观测早期/快速甚低频（VLF）事件，与地球电离层波导中VLF信号传播和散射的数值模型一起使用，以直接测量相关电离层扰动的散射模式。当致病闪电位于南北向观测点阵列 700 公里范围内时，通常在不超过 2 或 3 个观测点观测到早期/快速 VLF 事件，这表明前向散射信号的窄波束。在所研究的不同情况下，前向散射图案表现出小于 30° 的 15 dB 波束宽度，与 90±30 km 的水平范围一致。
Simultaneous observations of early/fast Very Low Frequency (VLF) events at nine closely spaced (∼65 km) sites are used together with a numerical model of the propagation and scattering of VLF signals in the earth‐ionosphere waveguide to directly measure the scattering pattern of associated ionospheric disturbances. In cases when the causative lightning is within 700 km of the north‐south array of observing sites, early/fast VLF events are typically observed at no more than 2 or 3 sites, which indicates a narrow beam of the scattered signal in the forward direction. In the different cases studied, forward scattering patterns exhibit 15 dB beamwidths of less than 30° consistent with horizontal extent of 90±30 km.