Galactic cosmic rays, heliospheric environment, and the terrestrial climate for the past 40,000 years

2017 Fiscal Year Final Research Report

• Project/Area Number: 25287051
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Musashino Art University
• Principal Investigator: Miyahara Hiroko 武蔵野美術大学, 造形学部, 准教授 (00532681)
• Co-Investigator(Kenkyū-buntansha): 堀内 一穂 弘前大学, 理工学研究科, 助教 (00344614) ; 櫻井 敬久 山形大学, 理学部, 客員教授 (60150265) ; 草野 完也 名古屋大学, 宇宙地球環境研究所, 教授 (70183796)
• Co-Investigator(Renkei-kenkyūsha): YOKOYAMA Yusuke 東京大学, 大気海洋研究所, 教授 (10359648) ; TOKANAI Fuyuki 山形大学, 理学部, 教授 (80323161)
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 太陽活動 / 宇宙線 / 太陽圏 / 気候変動 / 宇宙線生成核種 / 宇宙気候学 / 小氷期 / 雷

Outline of Final Research Achievements

In this study, we analyzed the cosmogenic nuclides in tree rings and ice cores to investigate the periodic variations of solar activity and the galactic cosmic rays in the past. Based on the time profile, we also examined the long-term variations of large-scale structure of heliospheric magnetic field. In addition, we conducted measurements of oxygen isotopes in tree rings to understand the solar influence on climate. As a result, it turned out that solar activity plays important role in the variations of precipitation in addition to the temperatures. We also examined the possible solar influence on meteorological phenomena focusing on the solar rotational period. As a result, it was suggested that solar activity shows a significant impact even at a meteorological time scale.

Free Research Field

宇宙線物理学, 太陽物理学, 宇宙気候学