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Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Observed by the FALMA in Winter Thunderstorms in Japan
Journal of Geophysical Research: Atmospheres ( IF 3.8 ) Pub Date : 2020-09-30 , DOI: 10.1029/2020jd033039
Ting Wu 1 , Daohong Wang 1 , Nobuyuki Takagi 1
Affiliation  

Multiple‐stroke (MS) positive cloud‐to‐ground (+CG) lightning flashes are rarely reported, especially those with high‐quality location information. In this study, we report 47 MS +CG flashes observed in winter thunderstorms in Japan with a 14‐site fast antenna lightning mapping array (FALMA). MS +CG flashes account for 18% of +CG flashes. The mean multiplicity of all +CG flashes is 1.24, and the maximum multiplicity is 5. Interstroke intervals have a very large range from 1.0 to 1,320.6 ms with the geometric mean of 64.4 ms. In three flashes, interstroke intervals smaller than 2 ms are observed, and corresponding positive strokes are inferred to be produced by two branches of the same positive leader. Horizontal distances between sequential positive strokes range from 1.1 to 37.3 km with the geometric mean of 9.7 km. No subsequent strokes struck at the same location as a previous stroke. Distances between sequential strokes are generally much larger than distances between first strokes and lightning initiation locations. Subsequent stroke peak amplitudes are on average 0.45 of first stroke peak amplitudes. In 39 flashes (83%), the first stroke is stronger than the largest subsequent stroke in the same flash. Subsequent stroke amplitudes are weakly correlated with the time difference from the previous stroke. Origination mechanisms of positive leaders initiating first and subsequent positive strokes are discussed. It is very likely that positive leaders for most subsequent strokes originate from in‐cloud negative leader channels, but origination mechanisms for positive leaders initiating first strokes are more varied.

中文翻译:

FALMA在日本冬季雷暴天气中观察到的多冲程正云对地闪电

很少报告多冲程(MS)云对地(+ CG)闪电,特别是那些具有高质量位置信息的闪电。在这项研究中,我们报告了日本的冬季雷暴天气中使用14个站点的快速天线闪电映射阵列(FALMA)观测到47次MS + CG闪烁。MS + CG闪烁占+ CG闪烁的18%。所有+ CG闪烁的平均多重性为1.24,最大多重性为5。笔画间隔介于1.0到1,320.6 ms之间,几何平均值为64.4 ms。在三次闪烁中,观察到的笔画间隔小于2 ms,并且推断出相同的正极笔画的两个分支会产生相应的正极笔画。连续正向击球之间的水平距离范围为1.1到37.3 km,几何平均值为9.7 km。没有后续的笔触与上一个笔触在相同的位置。顺序笔划之间的距离通常比第一笔划和闪电开始位置之间的距离大得多。随后的冲程峰值幅度平均为第一冲程峰值幅度的0.45。在39次闪烁(占83%)中,第一个笔划比同一次闪光中最大的后续笔划要强。随后的笔画幅度与上一次笔画的时间差之间存在弱关联。讨论了积极领导者发起第一个和随后的积极中风的起源机制。大部分后续笔画的积极领导者很可能起源于云中的负面领导者渠道,但积极领导者开始首笔的起源机制却更加多样。顺序笔划之间的距离通常比第一笔划和闪电开始位置之间的距离大得多。随后的冲程峰值幅度平均为第一冲程峰值幅度的0.45。在39次闪烁(占83%)中,第一个笔划比同一次闪光中最大的后续笔划要强。随后的笔画幅度与上一次笔画的时间差之间存在弱关联。讨论了积极领导者发起第一个和随后的积极中风的起源机制。大部分后续笔画的积极领导者很可能起源于云中的负面领导者渠道,但积极领导者开始首笔的起源机制却更加多样。顺序笔划之间的距离通常比第一笔划和闪电开始位置之间的距离大得多。随后的冲程峰值幅度平均为第一冲程峰值幅度的0.45。在39次闪烁(占83%)中,第一个笔划比同一次闪光中最大的后续笔划要强。随后的笔画幅度与上一次笔画的时间差之间存在弱关联。讨论了积极领导者发起第一个和随后的积极中风的起源机制。大部分后续笔画的积极领导者很可能起源于云中的负面领导者渠道,但积极领导者开始首笔的起源机制却更加多样。
更新日期:2020-10-13
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