Relationship between Tropical Pacific Ocean-Atmosphere Interaction and Northern Hemisphere Glaciation during the late Cenozoic

• Project/Area Number: 18H01279
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 17020:Atmospheric and hydrospheric sciences-related
• Research Institution: Kanazawa University
• Principal Investigator: Sagawa Takuya 金沢大学, 地球社会基盤学系, 助教 (40448395)
• Co-Investigator(Kenkyū-buntansha): 松崎 賢史 東京大学, 大気海洋研究所, 助教 (50728582) ; 山本 正伸 北海道大学, 地球環境科学研究院, 教授 (60332475) ; 久保田 好美 独立行政法人国立科学博物館, 地学研究部, 研究主幹 (80710946)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2021: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000); Fiscal Year 2020: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2019: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2018: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
• Keywords: 西部熱帯太平洋 / 鉛直水温構造 / 浮遊性有孔虫 / 鮮新世 / 更新世 / 大気海洋相互作用 / 熱帯太平洋域 / 国際深海科学掘削計画 / 水温復元 / 熱帯太平洋

Outline of Final Research Achievements

To investigate the relationship between changes in vertical temperature structure in the western tropical Pacific and global climate change, I analyzed planktonic foraminiferal shell geochemistry for three species picked from sediment core drilled in the International Ocean Discovery Program. The thickness of surface mixed layer was estimated by reconstructing vertical temperature structure from surface to subsurface for the last 4 Myr. The results suggested that the vertical temperature structure change has been associated with the meridional temperature gradient from tropics to polar region.

Academic Significance and Societal Importance of the Research Achievements

西部熱帯太平洋は全球で最も温暖な海水が存在し、大気に向けて熱や水蒸気を供給し大気循環を駆動する役割を果たしている。そのため、当該海域の水温や暖水塊厚さの時間的変化と全球気候の関係性を理解することが、地球気候システムの理解の一助になる。本研究で明らかになった熱帯－極域の温度勾配と西部熱帯太平洋の暖水塊厚さが連動していたことは、極域の温度変化にともなう南北温度勾配の変化が大気循環を通じて熱帯域の大気海洋相互作用に変化を与える可能性を示唆する。

Research Products

• [Int'l Joint Research] Rutgers University/University of California, Santa Cruz(米国)
• [Int'l Joint Research] University Collage of London(英国)
• [Int'l Joint Research] ラトガーズ大学(米国)
• [Int'l Joint Research] ラトガース大学(米国)
• [Int'l Joint Research] ブレーメン大学(ドイツ)
• [Journal Article] Tropical Western Pacific Hydrology During the Last 6,000?Years Based on Wildfire Charcoal Records From Borneo (2021)
  • Author(s): Yamamoto Masanobu、Kikuchi Takafumi、Sakurai Hiromichi、Hayashi Ryoma、Seki Osamu、Omori Takayuki、Sulaiman Abdullah、Shaari Hasrizal、Abdullah Mohd Zulhilmy、Melling Lulie
  • Journal Title: Geophysical Research Letters Volume: 48 Issue: 18
  • DOI: 10.1029/2021gl093832
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A deep-sea agglutinated foraminifer tube constructed with planktonic foraminifer shells of a single species (2018)
  • Author(s): Paul N. Pearson, Takuya Sagawa, and IODP Expedition 363 Shipboard Scientific Party
  • Journal Title: Journal of Micropalaeontology Volume: 37 Issue: 1 Pages: 97-104
  • DOI: 10.5194/jm-37-97-2018
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Western Pacific Warm Pool (2018)
  • Author(s): Rosenthal, Y., Holbourn, A.E., Kulhanek, D.K., Sagawa, T. and the Expedition 363 Scientists
  • Journal Title: Proceedings of the International Ocean Discovery Program Volume: 363
  • DOI: 10.14379/iodp.proc.363.2018
  • Open Access / Int'l Joint Research
• [Presentation] Evolution of meridional and zonal sea surface temperature gradients in the Pacific Ocean during the Quaternary period (2021)
  • Author(s): Takuya Sagawa, Risako Makino, Yukimi Kubota, Yoshimi Kubota, Yair Rosenthal
  • Organizer: Japan Geoscience Union 2021 conference
  • Int'l Joint Research
• [Presentation] Pliocene thermocline stability in the western Pacific warm pool inferred from the individual foraminifera analysis (2021)
  • Author(s): Fumito Mizuno, Takuya Sagawa
  • Organizer: Japan Geoscience Union 2021 conference
  • Int'l Joint Research
• [Presentation] Integrated stratigraphy of the sediment core retrieved from the Manihiki Plateau in the central Pacific and the paleotemperature change for the last 800 kyr (2021)
  • Author(s): Misaki Urakami, Takuya Sagawa, Yoshimi Kubota
  • Organizer: Japan Geoscience Union 2021 conference
• [Presentation] 後期鮮新世以降の西太平洋暖水塊における表層・亜表層水温 (2019)
  • Author(s): 佐川拓也、久保田礼実、牧野梨沙子、久保田好美、Yair Rosenthal
  • Organizer: 地球環境史学会2019年年会
• [Presentation] 過去100万年間の西赤道太平洋暖水塊における鉛直水温構造の復元 (2019)
  • Author(s): 水野 文人、佐川 拓也、向田 圭祐、久保田 好美、山崎 俊嗣、黒田 潤一郎
  • Organizer: 地球惑星科学連合2019年大会
• [Remarks] プロジェクト紹介 IODP Expedition 363
  • URL: http://earth.s.kanazawa-u.ac.jp/~tsagawa/project_Exp363.html
• [Funded Workshop] Kanazawa University SAKIGAKE International Symposium (2021)