气候变化领域集成服务门户(CCPortal): The Spatial Evolution of Upward Positive Stepped Leaders Initiated From a 356-m-Tall Tower in Southern China

CCPortal

DOI	10.1029/2019JD031508
	The Spatial Evolution of Upward Positive Stepped Leaders Initiated From a 356-m-Tall Tower in Southern China
	Gao Y.; Chen M.; Qin Z.; Qiu Z.; Yang Y.; Du Y.-P.; Wang S.; Zhang G.
发表日期	2020
ISSN	2169897X
卷号	125 期号:2
英文摘要	Two initial upward positive leaders (UPLs) in upward negative flashes initiated from a 356-m-tall tower were observed with a high-speed camera, an electric field sensor, and a magnetic field sensor. Although the waveforms of electric fields measured were saturated, both camera images and magnetic fields showed that the two UPLs had obvious stepwise characteristics in their upward moving stage. The magnetic fields associated with the UPLs were characterized by a series of fast-changing bipolar impulses superimposed on a slowly increasing continuous component as the leaders moved upward, which were well corresponding to the light intensity changes of their high-speed camera images. The 2-D step length and step extension speed of the two leaders were estimated in the range of 0.5–3 m and 1.1–9.4 × 105 m/s, respectively. The radius of the leader luminous channel as a function of time and height was also estimated. The channel radius showed first a stable increasing trend in the leader upward moving stage and then 4–5 times of shrinking and expanding processes after the leader connected the cloud. The channel expanding and shrinking speeds were in the range of 2–9 × 104 m/s. Particularly, the channel radius showed an obvious increasing trend with the increase of the height all the time, which was in the range of 2.8–3.5 m when around the tower tip and of 5.6–8.4 m when at 24 m high above the tower tip. Such a feature of the channel radius is in good agreement with the concept of leader corona sheath in literature. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	leader channel evolution; tall tower; upward flash; upward positive stepped leader
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/186220
作者单位	Department of Building Service Engineering, The Hong Kong Polytechnic University, Hong Kong; Shenzhen Meteorological Services Center, Shenzhen, China
推荐引用方式 GB/T 7714	Gao Y.,Chen M.,Qin Z.,et al. The Spatial Evolution of Upward Positive Stepped Leaders Initiated From a 356-m-Tall Tower in Southern China[J],2020,125(2).
APA	Gao Y..,Chen M..,Qin Z..,Qiu Z..,Yang Y..,...&Zhang G..(2020).The Spatial Evolution of Upward Positive Stepped Leaders Initiated From a 356-m-Tall Tower in Southern China.Journal of Geophysical Research: Atmospheres,125(2).
MLA	Gao Y.,et al."The Spatial Evolution of Upward Positive Stepped Leaders Initiated From a 356-m-Tall Tower in Southern China".Journal of Geophysical Research: Atmospheres 125.2(2020).