Global Distribution of Superbolts
Global Distribution of Superbolts
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DOI：
10.1029/2019jd030975
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发表时间：
2019-09-18
影响因子：
4.4
通讯作者：
Rodger, C. J.
中科院分区：
文献类型：
--
作者：
Holzworth, R. H.;McCarthy, M. P.;Rodger, C. J.
我们使用全球闪电定位网络（WWLLN）的数据上的辐射射频电磁能量每中风，以确定全球雷击能量分布的上端。在5和18 kHz之间的极低频带中，平均笔划能量约为每笔划1，000 J，而本文中使用的分布仅限于高于1 MJ的频带中的笔划，约比平均值高3个数量级。结果表明，这些能量代表了光分布的尖端，Turman（1977）首次确定了每冲程10 GW以上的能量，他称之为“超级闪电”。“全球分布高峰在北方半球冬季（11月至2月），大多数超级螺栓被发现在欧洲西部的北大西洋，冬季地中海，并在南美洲的安第斯山脉强烈的局部最大值。我们确定在北太平洋日本以东的冬季，沿着大西洋和印度洋的赤道和南非南部的超级螺栓较少的地区。每年4月至10月期间，我们很少发现超级螺栓。虽然超级闪电分散在地球仪周围，但局部发生的峰值并不与通常的三个主要闪电“烟囱”相吻合。“与所有正常全球闪电的分布不同，我们发现超级闪电主要分布在海洋和海洋上，大陆上的数量较少，与所有全球闪电相反。
We use World Wide Lightning Location Network (WWLLN) data on the radiated radio frequency electromagnetic energy per stroke to identify the upper tip of the global lightning stroke energy distribution. The mean stroke energy is about 1,000 J per stroke in the very low frequency band between 5 and 18 kHz, while the distribution used in this paper is limited to strokes in that band above 1 MJ, about 3 orders of magnitude above the mean. It is shown that these energies are representative of the tip of the optical distribution, first identified by Turman (1977) above 10 GW per stroke, which he termed "superbolts." The distribution peaks globally in the Northern Hemisphere winter (November-February) with most superbolts being found in the North Atlantic west of Europe, the winter Mediterranean Sea, and a strong local maximum over the Andes in South America. We identify regions with somewhat fewer superbolts in the North Pacific east of Japan in winter, along the equator of the Atlantic and Indian Oceans and south of South Africa. We find very few superbolts during April-October each year. While superbolts are scattered around the globe, the local occurrence peaks do not coincide with the usual three main lightning "chimneys." Unlike the distribution of all normal global lightning, we find superbolts predominantly over the oceans and seas, with fewer over the continents, just the opposite of all global lightning.