In‐Cloud Discharge of Positive Cloud‐To‐Ground Lightning and Its Influence on the Initiation of Tower‐Initiated Upward Lightning
In‐Cloud Discharge of Positive Cloud‐To‐Ground Lightning and Its Influence on the Initiation of Tower‐Initiated Upward Lightning
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DOI：
10.1029/2021jd035600
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
Shanfeng Yuan;X. Qie;R. Jiang;Dongfang Wang;Yu Wang;Caixia Wang;A. Srivastava;Ye Tian
中科院分区：
文献类型：
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作者：
Shanfeng Yuan;X. Qie;R. Jiang;Dongfang Wang;Yu Wang;Caixia Wang;A. Srivastava;Ye Tian
我们利用高速视频和北京宽带闪电网(BLNET)，在2012-2020年夏季对塔基向上闪电(UL)进行了全面的观测。共观察到25次UL闪电，其中21次是由附近的正地闪电触发的。有趣的是，有8次(38%)的父母+CG闪电有超过一次的回击(RS)。UL距母体+CG闪电接地点的距离为4~38公里，其中9个(43%)的UL是在正RS后2ms内触发的，其中11个(52%)是在5~187ms的长时间延迟后触发的。根据高速视频和测绘结果，短暂的时间延迟与塔上方腐烂的已建立的领导者重新激活有关。这一长时间的延迟与持续时间较长的洋流期间负先导延伸至塔楼上方区域有关。RS期间或当前持续期间的正电磁场变化有利于上升领导者的开始。虽然预击穿(PB)和RS在+CG闪光中都产生了正电场变化，但PB诱导的向上正导联终止了其在+RS后的持续传播。
We conducted a comprehensive observation of tower‐initiated upward lightning (UL) during the summer season from 2012 to 2020, using high‐speed video and the Beijing Broadband Lightning Network (BLNET). A total of 25 UL flashes were observed, and 21 of them were triggered by nearby positive cloud‐to‐ground (CG) lightning. It is interesting to note that eight (38%) of the parent +CG lightning flashes have more than one return stroke (RS). The distance between the UL and the grounding point of its parent +CG lightning was 4–38 km, where nine (43%) of the UL were triggered less than 2 ms after the positive RS, and 11 (52%) of them were triggered after a long time delay of 5–187 ms. Based on high‐speed video and mapping results, the short time delay was associated with the reactivation of the decayed established leader above the tower. The long time delay was associated with the negative leader extending to the region above the tower during the long continuing current. The positive E‐field change during RS or continuing current period favored the inception of an upward leader. Although both preliminary breakdown (PB) and RS in a +CG flash produced positive E‐field changes, an upward positive leader induced by PB aborted its sustained propagation after +RS.