Characterization of the initial stage in upward lightning at the Gaisberg Tower: 1. Current pulses
Characterization of the initial stage in upward lightning at the Gaisberg Tower: 1. Current pulses
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DOI：
10.1016/j.epsr.2022.108626
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发表时间：
2022
影响因子：
3.9
通讯作者：
N. Watanabe;A. Nag;G. Diendorfer;H. Pichler;W. Schulz;H. Rassoul
中科院分区：
文献类型：
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作者：
N. Watanabe;A. Nag;G. Diendorfer;H. Pichler;W. Schulz;H. Rassoul
我们研究了2006-2014年发生在奥地利萨尔茨堡附近的Gaisberg塔的58次向上闪光的电流波形。这些闪光的初始阶段（IS）包括相对缓慢变化的“背景”电流，其中更快、更脉冲的电流变化覆盖在该背景电流上。在58次闪光中，有46次（79%）的背景持续电流为负，另外12次闪光（21%）为双极。在这58次闪光的IS期间发生了1180个电流脉冲，其中708个（60%）为正双极（正初始极性，负相反极性过冲），28个（2.4%）为正单极（正初始极性，无相反极性过冲），440个（37%）为负单极，4个（0.3%）为负双极脉冲。我们发现，双极电流脉冲只发生在早期的IS。我们将IS电流分为两个阶段：（1）上行先导启动和传播阶段（IPP）和（2）上行先导成熟阶段（MP）。在IPP期间发生901或76%（712个双极和189个单极）脉冲，在MP期间发生279或21%（单极）脉冲。IPP脉冲的背景峰值电流中值为134 A，MP脉冲的背景峰值电流中值为687 A。
We examined current waveforms for 58 upward flashes occurring in 2006–2014 initiated from the Gaisberg Tower located near Salzburg, Austria. The initial stage (IS) of these flashes comprised of relatively slowly varying “background” current, with faster, more impulsive current variations overlaid on this background current. In 46 of the 58 flashes (79%) the background continuing current was negative, and in the other 12 flashes (21%) it was bipolar. 1180 current pulses occurred during the IS of these 58 flashes, of which 708 (60%) were positive bipolar (positive initial polarity with a negative opposite polarity overshoot), 28 (2.4%) were positive unipolar (positive initial polarity with no opposite polarity overshoot), 440 (37%) were negative unipolar, and four (0.3%) were negative bipolar pulses. We found that bipolar current pulses only occurred in the IS at early times. We divided the IS current into two phases: (1) upward leader initiation and propagation phase (IPP) and (2) upward leader mature phase (MP). 901 or 76% (712 bipolar and 189 unipolar) pulses occurred during the IPP, and 279 or 21% (unipolar) pulses occurred during the MP. The median background-to-peak current was 134 A for IPP pulses and 687 A for MP pulses.