Multidisciplinary studies of lightning for the disaster mitigation on the summit of Mt. Fuji

• Project/Area Number: 20H02419
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: University of Shizuoka
• Principal Investigator: Kamogawa Masashi 静岡県立大学, その他部局等, 特任教授 (00329111)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000); Fiscal Year 2022: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2021: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000); Fiscal Year 2020: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
• Keywords: 雷 / 高高度放電発光現象 / 自然放射線 / 接地 / 大気電場 / 富士山 / 放射線 / 大気化学 / 雷雲 / 豪雨 / 被雷 / 大気電気 / 夏季雷 / 冬季雷

Outline of Research at the Start

人的災害や、電気施設・低電圧機器への被害など被害回避のために落雷発生予測などの減災のニーズは高い。しかし、雷研究分野はいまだ重要な未解明問題が多々あり、落雷予測等を困難にさせている。未解明問題が多い理由は、測定器への被雷で直近観測が極めて困難、可視観測では雲に遮られやすい、以上2つを解決すると思われる雷電波測定では目的とする分解能・検知率が得られないなどの技術的困難のためである。本研究では、これらの技術的問題・制限を解決する雷雲雲底高度に届く富士山頂にて雷放電直近観測及び下層雲より高い山頂高度から広視野で雷や積乱雲の観測を行い、落雷防災へ向けた雷・関連研究の重要な基礎的課題を解決する。

Outline of Final Research Achievements

At Mt. Fuji, we have conducted several studies related to lightning and obtained the following results. A mountain-scale lightning observation system was developed to measure the telluric current flowing through a grounded conductor connected to the root of Mt. Fuji. We detected terrestrial gamma-ray flashes (TGFs) with X-rays generated from stepped leaders in the energic radiation observations of thunderclouds and lightning activity. In the observation of transient luminous events such as sprites, we showed the relationship between the amount of rainfall and the occurrence of sprites. The operation of a newly-designed field mill with wide-range measurements was tested.

Academic Significance and Societal Importance of the Research Achievements

雷放電直近観測および雷放電関連現象を含む全容観測が可能な富士山頂という日本最高峰かつ独立峰の長所を生かした観測により、多種多様な成果を得ることができた。これらの成果が得られたことにより富士山頂という観測点が雷研究の優れたテストフィールドであることを示すことができた。

Research Products

• [Journal Article] An Alternative Methodology of Fair‐Weather Identification for Ground‐Based Measurement of AEF at the Polar Region (2023)
  • Author(s): Minamoto Yasuhiro、Kamogawa Masashi、Kadokura Akira、Sato Mitsuteru、Omiya Satoshi
  • Journal Title: Journal of Geophysical Research: Atmospheres Volume: 128 Issue: 5
  • DOI: 10.1029/2021jd035732
  • Peer Reviewed / Open Access
• [Journal Article] Lightning Observation System by Measuring Current Flowing through the Grounding Conductor on Mt. Fuji (2022)
  • Author(s): Yasumoto Masaru、Kamogawa Masashi、Sasaki Kazuya、Dokiya Yukiko
  • Journal Title: IEEJ Transactions on Fundamentals and Materials Volume: 142 Issue: 3 Pages: 67-79
  • DOI: 10.1541/ieejfms.142.67
  • NAID: 130008165763
  • ISSN: 0385-4205, 1347-5533
  • Year and Date: 2022-03-01
  • Peer Reviewed
• [Journal Article] Temporal and Spatial Evolution of Precipitation under the Summer Sprite Parent Mesoscale Convective Systems in Japan (2022)
  • Author(s): Suzuki Tomoyuki、Kamogawa Masashi、Fujiwara Hironobu、Hayashi Syugo
  • Journal Title: Atmosphere Volume: 13 Issue: 10 Pages: 1661-1661
  • DOI: 10.3390/atmos13101661
  • Peer Reviewed / Open Access
• [Journal Article] MCS Stratiform and Convective Regions Associated with Sprites Observed from Mt. Fuji (2022)
  • Author(s): Suzuki Tomoyuki、Kamogawa Masashi、Fujiwara Hironobu、Hayashi Syugo
  • Journal Title: Atmosphere Volume: 13 Issue: 9 Pages: 1460-1460
  • DOI: 10.3390/atmos13091460
  • Peer Reviewed / Open Access
• [Journal Article] Origin of the intense positive and moderate negative atmospheric electric field variations measured during and after Antarctic blizzards (2021)
  • Author(s): Minamoto Yasuhiro、Kamogawa Masashi、Kadokura Akira、Omiya Satoshi、Hirasawa Naohiko、Sato Mitsuteru
  • Journal Title: Atmospheric Research Volume: 263 Pages: 105812-105812
  • DOI: 10.1016/j.atmosres.2021.105812
  • Peer Reviewed
• [Book] 雷の疑問56 (2021)
  • Author(s): 鴨川 仁、吉田 智、森本健志
  • Total Pages: 238
  • Publisher: 成山堂書店
  • ISBN: 4425983912