Elucidation of global carbon cycle and its climate response

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01275
• 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: Tohoku University
• Principal Investigator: AOKI Shuji 東北大学, 理学研究科, 学術研究員 (00183129)
• Co-Investigator(Kenkyū-buntansha): 森本 真司 東北大学, 理学研究科, 教授 (30270424)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 二酸化炭素 / 酸素 / 炭素同位体 / 陸上生物圏 / 海洋

Outline of Final Research Achievements

Global scale observations of CO2 concentration, the carbon isotopic ratio (delta13C) of CO2, and oxygen concentration (delta(O2/N2)) in the atmosphere have been made since 2001. Based on the observed secular trends of CO2 concentration and delta(O2/N2) as well as anthropogenic CO2 emission data, the average uptake rates of the anthropogenic CO2 during 2001-2020 among the atmosphere, the terrestrial biosphere and the ocean were estimated to be 44±0.3％, 33±6％ and 23±6％, respectively. By using the observed CO2 and delta13C, the corresponding CO2 uptakes were in good agreement with the former method within the estimated error ranges. The terrestrial biospheric CO2 uptake showed large interannual variability in association with El Nino events.

Free Research Field

大気物理学

Academic Significance and Societal Importance of the Research Achievements

化石燃料消費によって大気に大量に放出された二酸化炭素が海洋と陸上植物によってどのくらい吸収され、大気にどのくらい在留するかを正確に求めることは、今後の地球温暖化予測にとって重要な課題である。本研究ではそれらをCO2濃度とO2濃度観測から求める方法と、CO2濃度とその炭素同位体から求める方法を用いて解析したが、２つの独立した手法から得られた結果が誤差の範囲で一致したことから、信頼性が高い結果が得られたと結論づけられる。