Processes in negative and positive CG lightning flashes detected from space by GLM
Processes in negative and positive CG lightning flashes detected from space by GLM
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DOI：
10.1016/j.epsr.2024.110183
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发表时间：
2024-04
影响因子：
3.9
通讯作者：
A. Leal;V. Rakov
中科院分区：
文献类型：
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作者：
A. Leal;V. Rakov
正负闪电涉及许多不同的过程，包括初步击穿、阶梯状先导和镖状先导、回击、持续电流、M分量等。地球同步运行环境卫星上的地球同步闪电测绘仪（GLM）（GOES 16、17和18）是一种光学闪电探测器，在最低点具有2 ms的时间分辨率和约8 km的空间分辨率。GLM提供三种类型的数据：事件、组和闪存。根据GLM的设计者，组数据的目的是跟踪个人的雷击。我们在亚马逊使用快速和慢速天线记录了宽带闪电电场，并将其与相应的GLM组数据（以焦耳为单位的光能）进行了比较，以研究GLM可以从太空中检测到什么样的闪电过程。基于包含56个笔画的15 -CG闪光和包含24个笔画的15 +CG闪光的样本，我们发现GLM在对应于-CG回击的89%的2 ms时间窗口和对应于+CG回击的96%的窗口中检测到一定的亮度。它还在100%的时间窗口中检测到亮度，这些时间窗口对应于正闪光中的初步击穿过程，而在负闪光中为53%。此外，GLM分别检测到与80%和40%的正闪和负闪中的第一冲程先导相关的光度发射。一般来说，GLM在探测正闪电过程时比在探测负闪电过程时更有效。
Negative and positive lightning flashes involve a number of different processes, including the preliminary breakdown, stepped and dart leaders, return strokes, continuing currents, M-components, etc. The Geostationary Lightning Mapper (GLM) onboard of Geostationary Operational Environmental Satellites (GOES 16, 17 and 18) is an optical lightning detector with a time resolution of 2 ms and spatial resolution of about 8 km at nadir. The GLM provides three types of data: events, groups, and flashes. According to GLM designers, the group data are intended to track individual lightning strokes. We recorded wideband lightning electric fields using fast and slow antennas in the Amazon and compared them with the corresponding GLM group data (optical energy in Joules) to investigate what lightning processes can be detected from space by GLM. Based on a sample of 15 -CG flashes containing 56 strokes and 15 +CG flashes containing 24 strokes, we found that GLM detected some luminosity in 89 % of 2 ms time windows corresponding to -CG return strokes and 96 % of windows corresponding to +CG return strokes. It also detected luminosity in 100 % of time windows corresponding to preliminary breakdown processes in positive flashes versus 53 % in negative flashes. Further, the GLM detected luminosity emissions associated with 80 % and 40 % of first-stroke leaders in positive and negative flashes, respectively. In general, GLM is more efficient in detecting processes in positive lightning flashes than in negative ones.