Japan Geoscience Union Meeting 2014

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International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM08_2PM1] Space Weather and Space Climate

Fri. May 2, 2014 2:15 PM - 4:00 PM 411 (4F)

Convener:*Ryuho Kataoka(National Institute of Polar Research), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Kanya Kusano(Solar-Terrestrial Environment Laboratory, Nagoya University), Toshifumi Shimizu(Institute of Space and Astronautical Science, JAXA), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Ayumi Asai(Unit for Synergetic Studies of Space, Kyoto University), Tatsuhiko Sato(Japan Atomic Energy Agency), Hidekatsu Jin(National Institude of Information and Communications Technology), Kiminori Itoh(Graduate School of Engineering, Yokohama National University), Hiroko Miyahara(College of Art and Design, Musashino Art University), Chair:Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University)

2:30 PM - 2:45 PM

[PEM08-22] Climate responses in central Japan and Taiwan to the cosmic ray intensifications during the Maunder Minimum

*Wataru SAKASHITA1, Yusuke YOKOYAMA1, Hiroko MIYAHARA2, Takahiro AZE3, Hitoshi YONENOBU4, Motonari OHYAMA5, Yasuharu HOSHINO6, Takeshi NAKATSUKA7 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.College of Art and Design, Musashino Art University, 3.Interactive Research Center of Science, Tokyo Institute of Technology, 4.Graduate School of Education, Naruto University of Education, 5.The Center for Academic Resources and Archives, Botanical Gardens, Tohoku University, 6.National Research Institute for Cultural Properties, Nara, 7.Research Institute for Humanity and Nature)

Keywords:Solar Magnetic Activity, Galactic Cosmic Ray, The Maunder Minimum, Tree-ring isotope

Relationship between solar variations and climate has been long discussed for various time scales. It is difficult to distinguish the impacts of the multiple solar parameters (total solar irradiance (TSI), solar ultraviolet (UV) radiation, and galactic cosmic rays (GCRs)) on climate, because these variations are nearly synchronized. However, GCR fluctuations related to solar magnetic activity have slightly different features compared to the other external forcing factors (TSI, UV). According to previous studies, the cosmic ray fluctuation was particularly unique during the Maunder Minimum (A. D. 1645-1715), when almost no sunspots were observed. Annually measured tree-ring Δ14C and ice-core 10Be data have shown that decadal variations of GCRs had been remarkably amplified during the Maunder Minimum. This characteristic amplification may be utilized to shed light on the GCR influence on climate. In this study, we employ tree rings that can reconstruct both annual climate (δ18O) and cosmic ray fluctuations (Δ14C) during the Maunder Minimum. By using these proxies, we can directly compare these reconstructions without any dating error. Annually measured tree-ring δ18O records from central Japan have shown significant wet climate at every remarkable GCRs enhancement. On the other hand, there is no significant climate response in tree-ring δ18O record from Taiwan. We suggest that these climate responses may be related to a stationary position of the Baiu front. Recent satellite observations have shown that GCRs may cause the increase of low cloud amount at tropical western Pacific region. It can be suggested that cooling of tropical western Pacific region caused by GCR enhancement might have caused the weakening of Pacific high and indirectly brought wet rainy seasons in central Japan.