[P-EM12] Space Weather and Space Climate

[PEM12-25] Variation of carbon-14 in tree rings around the onset of the Spoerer Minimum

★Invited Papers

*宮原 ひろ子¹、門叶 冬樹²、森谷 透²、大山 幹成³、箱崎 真隆⁴、武山 美麗²、櫻井 敬久² (1.武蔵野美術大学、2.山形大学、3.東北大学、4.名古屋大学)

キーワード：太陽活動周期、太陽活動極小期、宇宙線生成核種

Solar activity in the past has been reconstructed using carbon-14 in tree rings and beryllium-10 in ice cores, and it has been indicated that the Sun has long-term activity cycles such as Gleissberg cycle (~88 yrs) and the de Vries cycle (~200 yrs). Long-term variations of solar activity sometimes bring the grand minima such as the Dalton Minimum (1800-1820 CE) and the Maunder Minimum (1645-1715 CE). The detailed mechanism of such grand minima, however, remain unsolved. Reconstruction of solar cycles around the onset of the grand minima may shed light on the process of the occurrence of grand minima. We therefore have been conducting high-precision measurement of carbon-14 in tree rings with annual resolution using the Accelerator Mass Spectrometer at the Yamagata University. In this paper, we present our recent results on the measurement of carbon-14 around the onset of the Spoerer Minimum.