Source region for whistlers detected at Rothera, Antarctica
Source region for whistlers detected at Rothera, Antarctica
复制标题
南极洲罗瑟拉发现口哨声的来源地区
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Steinbach
中科院分区：
文献类型：
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作者：
A. Collier;J. Lichtenberger;M. Clilverd;C. Rodger;P. Steinbach
[1]公认的哨声产生机制隐含地假定，诱因闪电发生在引导磁力线的共轭脚点附近，夜间哨声普遍存在，因为跨层衰减较低。然而，这些假设不一定是正确的。在这项研究中，我们考虑了南极半岛上Rothera站的哨声观测，并将它们的发生与来自世界闪电定位网络的全球闪电活动进行了对比。在罗瑟拉观测到的一跳哨声与全球闪电的相关性产生了几个显著正相关的区域。最有可能的震源区是在墨西哥湾流上方发现的，从共轭点向赤道方向略有移动。声源区域与共轭点的接近程度符合广为接受的哨声产生机制。然而，人们出人意料地偏向于海洋闪电，而不是附近的大陆闪电。Rothera哨声的昼夜模式与共轭闪电之间的关系显示出尚未解决的反常特征：哨声峰值出现在震源和接收方的白天以及震源闪电活动最低的时候。因此，我们认为晨区的优先哨波放大可能是高哨声发生的一个可能原因，尽管这不能解释偏向海洋闪电的原因。
[1] The accepted mechanism for whistler generation implicitly assumes that the causative lightning stroke occurs within reasonable proximity to the conjugate foot point of the guiding magnetic field line and that nighttime whistlers are prevalent because of low transionospheric attenuation. However, these assumptions are not necessarily valid. In this study we consider whistler observations from Rothera, a station on the Antarctic Peninsula, and contrast their occurrence with global lightning activity from the World Wide Lightning Location Network. The correlation of one-hop whistlers observed at Rothera with global lightning yields a few regions of significant positive correlation. The most probable source region was found over the Gulf Stream, displaced slightly equatorward from the conjugate point. The proximity of the source region to the conjugate point is in accord with the broadly accepted whistler production mechanism. However, there is an unexpected bias toward oceanic lightning rather than the nearby continental lightning. The relationship between the diurnal pattern of the Rothera whistlers and the conjugate lightning exhibits anomalous features which have yet to be resolved: the peak whistler rate occurs when it is daytime at both the source and the receiver and when source lightning activity is at its lowest. As a result, we propose that preferential whistler-wave amplification in the morning sector is a possible cause of the high whistler occurrence, although this does not account for the bias toward oceanic lightning.