講演情報
[PEM04-32]A humid climate of the last stage of the Little Ice Age in central Japan reconstructed using oxygen isotopes from tree-ring
*坂下 渉1、宮原 ひろ子2、横山 祐典1、中塚 武3、阿瀬 貴博1、星野 安治4、大山 幹成5、米延 仁志6、竹村 恵二7 (1.東京大学 大気海洋研究所、2.武蔵野美術大学造形学部、3.総合地球環境学研究所、4.奈良文化財研究所、5.東北大学学術資源研究公開センター植物園、6.鳴門教育大学大学院学校教育研究科、7.京都大学大学院理学研究科附属地球熱学研究施設)
キーワード：
Little Ice Age、Monsoon、tree-ring、oxygen isotopes
The Asian monsoon is an important part of the Earth’s climate system that is characterized by variations in the strength and expansion of the summer rain band. Rainfall reconstructions in China have revealed changing patterns of rainfall during the Little Ice Age (LIA), but few hydroclimate reconstructions around Japan have hindered the understanding of physical processes associated with the atmospheric system in the western North Pacific. Here, we report on rainfall variations in the Meiyu/Baiu season from AD 1600–1959 by using tree-ring cellulose oxygen isotopes from central Japan; this is the longest record in the eastern most regions under the monsoon’s influence. Data suggest that the wettest period occurred around AD 1790–1860, the final stage of the LIA. This shift was concurrent with sea surface temperature anomalies around the Philippines and off eastern Japan. Thus, meridional atmospheric circulation was likely weak during the last stage of the LIA.