气候变化领域集成服务门户(CCPortal): On a Possible Mechanism of Reactivation of Decayed Branches of Negative Stepped Leaders

CCPortal

DOI	10.1029/2020JD033305
	On a Possible Mechanism of Reactivation of Decayed Branches of Negative Stepped Leaders
	Ding Z.; Rakov V.A.; Zhu Y.; Tran M.D.
发表日期	2020
ISSN	2169897X
卷号	125 期号:23
英文摘要	Using visible-range and infrared (3–5 μm) high-speed video cameras, we observed luminosity transients that reilluminated decayed branches of two close (2 to 4 km) negative stepped leaders in Florida. Leader branches were energized via stepping at their tips and, as a result, were most heated near their lower ends, with the hotter sections being connected via cooler sections to the trunk. In the modeling of lightning leaders, usually a single tip is considered. In contrast, in the present study, many (up to 30 per major branch) tips were active at the same time, forming a network-like structure with a descending multitip “ionization front” whose transverse dimensions were of the order of hundreds of meters. The front exhibited alternating stepping, with each step necessarily generating a positive charge wave traveling from the leader tip up along the channel, like a mini return stroke. We inferred that the step-related waves can cause luminosity transients in the remnants of decayed negative branches at higher altitudes. Such reactivated branches, in turn, may facilitate further leader stepping at lower altitudes, as first reported by Stolzenburg et al. (2015, https://doi.org/10.1002/2014JD022933). The reactivation process is likely to involve multiple steps, as evidenced by a large number of active tips (some tens per 50-μs frame) and corresponding electric field pulses occurring at time intervals of 2 μs or less. Additionally, our observations suggest that a transient in one decayed branch can trigger (or assist with triggering of) a transient in another branch. © 2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185615
作者单位	Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, United States; Earth System Science Center, University of Alabama in Huntsville, Huntsville, AL, United States; Rhombus Power Inc., Moffett Field, CA, United States
推荐引用方式 GB/T 7714	Ding Z.,Rakov V.A.,Zhu Y.,et al. On a Possible Mechanism of Reactivation of Decayed Branches of Negative Stepped Leaders[J],2020,125(23).
APA	Ding Z.,Rakov V.A.,Zhu Y.,&Tran M.D..(2020).On a Possible Mechanism of Reactivation of Decayed Branches of Negative Stepped Leaders.Journal of Geophysical Research: Atmospheres,125(23).
MLA	Ding Z.,et al."On a Possible Mechanism of Reactivation of Decayed Branches of Negative Stepped Leaders".Journal of Geophysical Research: Atmospheres 125.23(2020).