Understanding the variation factor of 17O-excess in an ice core and reducing in uncertainty of climate change assessment

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K16184
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Nagoya University (2018); Research Institute for Humanity and Nature (2016-2017)
• Principal Investigator: Tsushima Akane 名古屋大学, 環境学研究科, 研究員 (70757682)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 水安定同位体比 / 17O-excess / d-excess / 雪氷試料 / 古環境復元 / 気候変動 / 北極域

Outline of Final Research Achievements

The stable water isotope ratios (δ18O, δD and d-excess) in ice cores are important proxy of paleo climate change. Recently, δ17O and 17O-excess which is calculated from δ18O and δ17O have attracted attention as a promising new proxy of hydro-climate variation. However, little is known about 17O-excess in an ice core. In this study, we measured δ17O, δ18O and δD in an ice core, which was obtained from Alaska and the northwest Greenland using Wavelength-Scanned Cavity Ring-Down Spectroscopy (model L2140-i; Picarro). In addition, we calculated d-excess and 17O-excess form those. Our results suggested that the running correlation between 17O-excess and d-excess are responding to climate changes.

Free Research Field

雪氷学

Academic Significance and Societal Importance of the Research Achievements

地球の気候環境変動の将来予測の不確実性の低減化には，古環境指標から引き出される過去の環境変動情報の高精度化が重要な課題の一つとなる．本研究では、アイスコアから復元される過去の環境変動情報の高精度化を目的として，新たな水安定同位体比 δ17O および 17O-excess に着目しており，本研究で復元された精度の高い北極域の過去の環境変動情報は，社会的意義のある知見である．また，アイスコア中の δ17O および 17O-excessは未だ測定例が非常に少なく貴重なため，それらのデータの取得は学術的にも重要な意義がある．