Atmospheric electricity coupling between earthquake regions and the ionosphere
Atmospheric electricity coupling between earthquake regions and the ionosphere
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DOI：
10.1016/j.jastp.2009.12.004
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发表时间：
2010-04-01
影响因子：
1.9
通讯作者：
Rycroft, M. J.
中科院分区：
文献类型：
--
作者：
Harrison, R. G.;Aplin, K. L.;Rycroft, M. J.
我们提出了一种机制来解释地震活动与架空探测到的电离层变化之间的联系。具体来说，我们解释了最近在夜间DEMETER卫星上观测到的上层电离层自然极低频（ELF）无线电噪声的变化，在大地震之前。我们的机制利用了大地震前表层空气电导率的增加，从而降低了表面电离层的电阻。这增加了垂直的晴天电流，并且（为了保持电子流的连续性）降低了电离层。对关键参数的大小进行了估计，发现与观测结果一致。电离层和大气电学性质的自然变率被评估，并且可以使用混合探测方法来克服。研究这种机制的建议实验包括测量极低频“tweeks”的截止频率，地球电离层波导中极低频无线电波的振幅和相位，或中频雷达，对电离层电子密度较低的非相干散射或火箭研究。2009爱思唯尔有限公司版权所有。
We propose a mechanism to explain suggested links between seismic activity and ionospheric changes detected overhead. Specifically, we explain changes in the natural extremely low-frequency (ELF) radio noise recently observed in the topside ionosphere aboard the DEMETER satellite at night, before major earthquakes. Our mechanism utilises increased electrical conductivity of surface layer air before a major earthquake, which reduces the surface-ionosphere electrical resistance. This increases the vertical fair weather current, and (to maintain continuity of electron flow) lowers the ionosphere. Magnitudes of crucial parameters are estimated and found to be consistent with observations. Natural variability in ionospheric and atmospheric electrical properties is evaluated, and may be overcome using a hybrid detection approach. Suggested experiments to investigate the mechanism involve measuring the cut-off frequency of ELF "tweeks", the amplitude and phase of very low frequency radio waves in the Earth-ionosphere waveguide, or medium frequency radar, incoherent scatter or rocket studies of the lower ionospheric electron density. (C) 2009 Elsevier Ltd. All rights reserved.