Beta-type stepped leader of elve-producing lightning
Beta-type stepped leader of elve-producing lightning
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DOI：
10.1029/2005gl023080
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发表时间：
2005-07-15
影响因子：
5.2
通讯作者：
Takahashi, Y
中科院分区：
文献类型：
--
作者：
Frey, HU;Mende, SB;Takahashi, Y
台湾FORMOSAT-2（前ROCSAT-2）航天器上的精灵和高层大气闪电成像仪（ISUAL）是第一个全球性的瞬态发光事件（TLEs）观测站。在最初的4个月里，大量的精灵被观察到。精灵的远紫外线（FUV）特征是显而易见的，与低海拔的精灵或闪电相比，在其发射高度上，大气O-2的衰减较小。大约有一半的精灵是由闪电产生的，在光度计信号中显示出三个步骤的特征：（1）除了FUV通道之外的所有通道中的初始亮度增加，（2）接下来的2 - 5毫秒的亮度缓慢下降，以及（3）所有通道中的信号脉冲增加。我们解释这个特定的签名作为最初的故障与β型阶梯领导人其次是明亮的回击负云对地（CG）闪电。相比之下，子闪电遵循正云对地闪电（+ CG），而没有初始击穿和步进先导的签名。许多子闪电与持续的电流有关，并且可以在闪电之后延迟高达100 ms。
The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) on the Taiwanese FORMOSAT-2 ( formerly ROCSAT-2) spacecraft is the first global observatory of transient luminous events (TLEs). During the first 4 months of operation a large number of elves were observed. Elves are obvious with their far ultraviolet (FUV) signature that is less attenuated by atmospheric O-2 at their emission altitude compared to emission from sprites or lightning at lower altitude. About half of all elves were produced by lightning that shows a three-step signature in the photometer signal: ( 1) An initial brightening in all except the FUV channels, ( 2) a slow brightness decrease for the next 2 - 5 milliseconds, and ( 3) an impulsive increase of signal in all channels. We interpret this specific signature as the initial breakdown with a beta-type stepped leader followed by the bright return stroke of a negative cloud to ground ( - CG) lightning. In contrast, sprites follow positive cloud to ground lightning (+ CG) without a signature of initial breakdown and stepped leader. Many sprites are associated with the continuing current and can be delayed up to 100 ms after the lightning.