基于LLS的多回击地闪及其雷电流幅值分布特征

为进一步研究多回击地闪参数分布特征,以便为雷电防护工程设计和雷电物理研究提供参考,根据湖北省雷电定位系统(LLS)2007年1月-2018年12月监测资料,采用计算机编程处理和数理统计方法,对多回击地闪次数、多重回击次数和不同类型多回击地闪雷电流幅值等参数进行了统计分析.结果 表明:多回击正地闪、负地闪和总地闪次数占其...

THE DISTRIBUTION CHARACTERISTICS OF MULTIPLE STROKES OF CLOUD-TO-GROUND LIGHTNING AND THEIR LIGHTNING CURRENT MAGNITUDE BASED ON LLS

To further investigate the distribution characteristics of multiple strokes of cloud-to-ground (CG) lightning, and to provide reference for the design of lightning protection engineering and lightning physics research, the present study analyzes the parameters such as multiple strokes lightning frequency, multiple return-strokes lightning frequency and lightning current magnitude for different types of multiple strokes lightning using computer programing and mathematical statistics method. These data were collected by the Lightning Location System (LLS) of Hubei Meteorological Service from January 2007 to December 2018. The results show that the percentage for multiple strokes of positive, negative and total CG lightning was 2.06%, 34.76% and 32.64% respectively, and the number of multiple return-strokes was 0.01%, 0.42% and 0.40% of the total number of return strokes respectively. The number of negative multiple strokes accounted for 99.69% of the multiple strokes of total CG lightning. The percentage of multiple strokes of positive and negative CG lightning in which the first return stroke intensity was greater than the subsequent was 82.52% and 57.87% of the total number of return strokes respectively. In the subsequent return stroke of multiple strokes, the percentage of the subsequent return stroke intensity of positive and negative CG lightning being greater than that of the first return stroke was about 9% and 20%, respectively. The median current for multiple strokes of positive and negative CG lightning was 59.30 kA and 35.10 kA, respectively. The first return stroke intensity was 90.90 kA and 40.00 kA, respectively, and the subsequent return stroke intensity was 43.90 kA and 33.00 kA, respectively. In the first return stroke, the cumulative probability for multiple strokes of positive and negative CG lightning in which current magnitude was greater than 100 kA was 44.06% and 4.64%, respectively. When the first return stroke intensity was greater than the subsequent return stroke intensity, the maximum cumulative probability of the positive and negative CG lightning in which current magnitude was greater than 100 kA was 52.21% and 7.94%, respectively. In the subsequent return stroke, the cumulative probability of multiple strokes of positive and negative CG lightning with current magnitude being less than or equaling to 40 kA was 41.80% and 69.92%, respectively. Besides, when the first return stroke intensity was greater than the subsequent return stroke intensity, the maximum cumulative probability of the negative CG lightning with current magnitude being less than or equaling to 40 kA was 77.71%. In the multiple strokes of positive and negative CG lightning, the ratio of the subsequent return stroke to the first return stroke was 0.48 and 0.83, respectively. The fitting results show that the cumulative probability formula of the current magnitude for multiple strokes of the positive and negative CG lightning with different types was significant. There was a significant positive correlation between the cumulative probability of lightning current magnitude near value a and value b in the fitting formula.