Identification of the occurrence conditions and mechanisms of transient luminous events from space- and ground-based observations

2015 Fiscal Year Final Research Report

• Project/Area Number: 24340117
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Hokkaido University
• Principal Investigator: SATO Mitsuteru 北海道大学, 理学(系)研究科(研究院), 講師 (50312541)
• Co-Investigator(Kenkyū-buntansha): USHIO Tomoo 大阪大学, 大学院工学研究科, 准教授 (50332961) ; MORIMOTO Takeshi 近畿大学, 大学院理工学研究科, 准教授 (60403169) ; HOBARA Yasuhide 電気通信大学, 大学院情報理工学研究科, 教授 (10303009) ; TAKAHASHI Yukihiro 北海道大学, 大学院理学研究院, 教授 (50236329) ; SUZUKI Makoto 宇宙航空研究開発機構, 宇宙科学研究所, 主幹研究員 (60142098)
• Co-Investigator(Renkei-kenkyūsha): TSUCHIYA Fuminori 東北大学, 大学院理学研究科, 助教 (10302077) ; OYA Hiroyo 千葉大学, 大学院工学研究科, 助教 (00241943) ; KAMOGAWA Masashi 東京学芸大学, 教育学部, 准教授 (00329111) ; NAKADA Hiroyuki 千葉大学, 大学院工学研究科, 助教 (30345011)
• Research Collaborator: ADACHI Toru
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: 雷放電 / 高高度放電発光現象 / スプライト / 国際宇宙ステーション

Outline of Final Research Achievements

The main objective of this research is to identify the occurrence conditions of sprites. For this purpose, the horizontal distributions of sprites and the electrical properties of the sprite-producing lightning discharges are studied using the data obtained by the JEM-GLIMS measurements at the ISS and using ground-based lightning data. First, we established the analytical method to identify weak sprite emissions from the incomparably intense lightning emissions in the JEM-GLIMS data. Based on the detailed data analyses of the 42 sprite events identified by that method, the spatial distributions of sprites and the horizontal displacement of the sprites from the sprite-producing lightning discharges are quantitatively identified. From the detailed comparison between the sprite distributions and source locations of the VHF pulses excited by the sprite-producing lightning currents, which is the first result in the world, the occurrence conditions of the sprites are clarified.

Free Research Field

超高層物理学，大気電気学