Does the geomagnetic excursion trigger climate change?

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K21497
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geology; Stratigraphy/Paleontology
• Research Institution: Ritsumeikan University
• Principal Investigator: KITABA Ikuko 立命館大学, 総合科学技術研究機構, 准教授 (60631710)
• Research Collaborator: MARK Darren グラスゴー大学, 教授 ; SMITH Victoria オックスフォード大学, 准教授 ; ALBERT Paul G. オックスフォード大学, 研究員 ; NAKAGAWA Takeshi 立命館大学, 総合科学技術研究機構, 教授 ; HYODO Masayuki 神戸大学, 内海域環境教育研究センター, 教授 ; WATANABE Masami 文化財調査コンサルタント株式会社, 代表取締役
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 気候変動 / 地磁気エクスカーション / モンスーン / 銀河宇宙線 / スベンスマルク効果 / 年縞堆積物 / 水月湖 / 定量的気候復元

Outline of Final Research Achievements

This research aimed to reveal the climatic impact of moderate weakening of the geomagnetic field. We carried out pollen analysis of the SG14 sediment core from Lake Suigetsu, Japan, and reconstructed the climate during the last interglacial period (MIS 5), which contains the Blake excursion. The temperature signal in MIS 5 was dominated by ca. 20-kyr oscillation, which gradually damped through cycles. This means that the long-term climate change was primarily controlled by the orbital forcing. When we removed the component which arose from the boreal summer insolation, the residual component in temperature was positively correlated with the paleomagnetic intensity measured in the same core between 110 ka and 130 ka. On the other hand, there was no clear correlation between paleointensity and monsoon signals.

Free Research Field

古気候学、宇宙気候学