Characteristics of channel base currents and close magnetic fields in triggered flashes in SHATLE
Characteristics of channel base currents and close magnetic fields in triggered flashes in SHATLE
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DOI：
10.1029/2010jd014420
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发表时间：
2010-12
影响因子：
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通讯作者：
Jing Yang;X. Qie;Guang-shu Zhang;Qilin Zhang;G. Feng;Yang Zhao;R. Jiang
中科院分区：
文献类型：
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作者：
Jing Yang;X. Qie;Guang-shu Zhang;Qilin Zhang;G. Feng;Yang Zhao;R. Jiang
利用2005 - 2009年山东省人工触发闪电实验（SHATLE）的观测资料，研究了通道基电流和近区磁场的统计分布。用数值方法研究了各种因素对近场磁场的影响。统计结果表明，回击峰值电流变化范围为5.8 ~ 45.7kA，几何平均值为14.1kA。电流波形中10-90%上升时间、30-90%上升时间和半峰宽度的GM与文献中发现的大多数结果一致。在60 m处，基于32次回击，磁场从18 μT变化到148 μT，GM为52 μT。磁场波形中10-90%上升时间的峰值在1 - 2 μs之间，最小值为0.4 μs，最大值为8.4 μs，与其他研究相比覆盖范围相对较宽。数值模拟结果表明，对于较大的回程速度，磁场峰值较大，半峰宽度和上升时间较小。距离对感应和辐射分量时变贡献的影响与回击速度和电流上升时间的影响完全不同。随着距离或电流上升时间的增加，磁场峰值减小，但上升时间和半峰宽增加。
Statistical distributions of channel base currents and close magnetic fields have been investigated by using data measured during Shandong Artificially Triggering Lightning Experiment (SHATLE) from 2005 to 2009. Effects of different factors on close magnetic fields have been examined by using numerical method. Statistical results showed that return stroke peak currents varied from 5.8 kA to 45.7 kA with a geometric mean (GM) of 14.1 kA. The GM of 10–90% risetime, 30–90% risetime, and half‐peak width in current waveforms were consistent with most of the results found in the literature. The magnetic fields at 60 m, based on 32 return strokes, varied from 18 μT to 148 μT with a GM of 52 μT. The peak value of the 10–90% risetime in magnetic field waveform was between 1 and 2 μs with a minimum of 0.4 μs and a maximum of 8.4 μs, covering a relatively wide range compared with other studies. The numerical modeling results showed that for larger return stroke speeds, the magnetic field peaks are larger, half‐peak widths and risetimes are smaller. Effects of distance on time‐variation contribution of induction and radiation components are quite different from that of return stroke speed and current risetime. With increasing the distance or current risetime, the magnetic field peak decreases, but the risetime and half‐peak width increase.