Japan Geoscience Union Meeting 2022

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[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS27] Atmospheric electricity: Atmospheric electricity and climate change

Wed. May 25, 2022 1:45 PM - 3:15 PM 104 (International Conference Hall, Makuhari Messe)

convener:Yasuhide Hobara(Graduate School of Information and Engineering Department of Communication Engineering and Informatics, The University of Electro-Communications), convener:Kenkichi NAGATO(National Institute of Technology, Kochi College), Chairperson:Kenkichi NAGATO(National Institute of Technology, Kochi College), Yasuhide Hobara(Graduate School of Information and Engineering Department of Communication Engineering and Informatics, The University of Electro-Communications)

2:15 PM - 2:30 PM

[MIS27-03] Classification of lightning discharges in winter thunderstorms of Hokuriku coincident with terrestrial gamma-ray flashes

*Yuuki Wada1,2, Takeshi Morimoto3, Yoshitaka Nakamura4, Ting Wu5, Teruaki Enoto2, Kazuhiro Nakazawa6, Tomoo Ushio1, Takayuki Yuasa, harufumi Tsuchiya7 (1.Osaka University, 2.RIKEN, 3.Kindai University, 4.KCCT, 5.Gifu University, 6.Nagoya University, 7.JAEA)

Keywords:terrestrial gamma-ray flash, lightning discharge, high-energy atmospheric physics

Most of terrestrial gamma-ray flashes (TGFs) have been so far detected by in-orbit satellites. On the other hand, a few downward TGFs reaching the ground have been also detected by ground-based observations. We have performed gamma-ray observations in Kanazawa, Ishikawa Prefecture, and Kashiwazaki, Niigata Prefecture, for four years, and detected a total of seven downward TGFs. Lightning discharges coincident with the downward TGFs were recorded by broadband low-frequency (LF) monitors installed in Toyama Prefecture. Four events are followed by a negative LF pulse with a peak current of <100 kA. It is indicated that the TGFs took place during the progression of stepped leaders. Also three of the four are multi-pulse TGFs, having multiple gamma-ray pulses with intervals of several milliseconds. The other three events are coincident with a large negative LF pulse with a peak current of >100 kA. According to Wu et al. (GRL, 2021), they are compact return strokes with short leader progression. Also all the three cases are single-pulse TGFs. The downward TGFs in the present study can be classified into two types based on the LF observations.