Davis C J, Johnson C G
Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, UK.
Nature. 2005 Jun 9;435(7043):799-801. doi: 10.1038/nature03638.
A connection between thunderstorms and the ionosphere has been hypothesized since the mid-1920s. Several mechanisms have been proposed to explain this connection, and evidence from modelling as well as various types of measurements demonstrate that lightning can interact with the lower ionosphere. It has been proposed, on the basis of a few observed events, that the ionospheric 'sporadic E' layer--transient, localized patches of relatively high electron density in the mid-ionosphere E layer, which significantly affect radio-wave propagation--can be modulated by thunderstorms, but a more formal statistical analysis is still needed. Here we identify a statistically significant intensification and descent in altitude of the mid-latitude sporadic E layer directly above thunderstorms. Because no ionospheric response to low-pressure systems without lightning is detected, we conclude that this localized intensification of the sporadic E layer can be attributed to lightning. We suggest that the co-location of lightning and ionospheric enhancement can be explained by either vertically propagating gravity waves that transfer energy from the site of lightning into the ionosphere, or vertical electrical discharge, or by a combination of these two mechanisms.
自20世纪20年代中期以来，人们就推测雷暴与电离层之间存在联系。已经提出了几种机制来解释这种联系，来自建模以及各种测量的证据表明闪电可以与较低的电离层相互作用。基于一些观测到的事件，有人提出电离层的“偶发性E层”（中电离层E层中相对高电子密度的瞬态、局部斑块，对无线电波传播有显著影响）可以被雷暴调制，但仍需要更正式的统计分析。在这里，我们确定了雷暴正上方中纬度偶发性E层在统计上有显著的增强和高度下降。由于未检测到电离层对无闪电低压系统的响应，我们得出结论，偶发性E层的这种局部增强可归因于闪电。我们认为，闪电与电离层增强的共存可以通过将能量从闪电位置转移到电离层的垂直传播重力波、垂直放电或这两种机制的组合来解释。
