Mapping thunder sources by inverting acoustic and electromagnetic observations
Mapping thunder sources by inverting acoustic and electromagnetic observations
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DOI：
10.1002/2014jd021624
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发表时间：
2014-12-16
影响因子：
4.4
通讯作者：
Thomas, R. J.
中科院分区：
文献类型：
--
作者：
Anderson, J. F.;Johnson, J. B.;Thomas, R. J.
本文提出了一种利用雷电记录反演雷电电流的新方法，该方法受雷电测绘阵列观测的约束。首先，连接射频(RF)脉冲以重建由引线创建的导电通道。然后，对流经每个通道的电流产生的声学信号进行正演模拟。所记录的雷声被认为由这些声信号的加权叠加组成。我们用马尔可夫链蒙特卡罗逆方法计算了每个通道的声源能量的后验分布，用来拟合模拟和记录的雷电的功率包络，这些结果显示了闪光的哪些部分携带电流并产生雷电。我们考察了射频脉冲定位不精确度和大气风对结果质量的影响，并将该方法应用于美国新墨西哥州马格达莱纳山脉的几次闪电。这种方法将使研究人员能够更详细地研究闪电现象，因为除了先导传播之外，研究人员还可以绘制电流流动图。
We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which parts of the flash carry current and produce thunder. We examine the effects of RF pulse location imprecision and atmospheric winds on quality of results and apply this method to several lightning flashes over the Magdalena Mountains in New Mexico, USA. This method will enable more detailed study of lightning phenomena by allowing researchers to map current flow in addition to leader propagation.