A revised interpretation of the relationship between d18O in snow and surface temperature over Antarctica

• Project/Area Number: 18K19851
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 63:Environmental analyses and evaluation and related fields
• Research Institution: Nagoya University
• Principal Investigator: Kurita Naoyuki 名古屋大学, 宇宙地球環境研究所, 准教授 (60371738)
• Co-Investigator(Kenkyū-buntansha): 堀内 一穂 弘前大学, 理工学研究科, 准教授 (00344614) ; 赤田 尚史 弘前大学, 被ばく医療総合研究所, 教授 (10715478) ; 保田 浩志 広島大学, 原爆放射線医科学研究所, 教授 (50250121)
• Project Period (FY): 2018-06-29 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000); Fiscal Year 2020: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000); Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
• Keywords: 酸素同位体比 / 南極 / ダイヤモンドダスト / 南極ドームふじ / 長期気候変動 / 地球温暖化 / 南極観測 / トリチウム / 水安定同位体比 / 大気輸送モデル / 宇宙線生成核種 / 宇宙線スペクトル予測モデル / 南極水循環

Outline of Final Research Achievements

The purpose of this study is to elucidate the physical background of the empirical relationship between precipitation isotopic composition and local temperature over Antarctica. In this study, several inland Antarctic surveys were conducted to obtain the spatiotemporal isotopic variability. Then, the key factor controlling the observed isotopic variability was identified from their results. It is noteworthy that the contribution of clear sky deposition of diamond dust characterized by very depleted isotopic composition increases toward the inland and the spatial distributions are linked to the relative ratio of diamond dust to total accumulation. In addition, this feature is also consistent with the temporal isotopic variations observed at Dome Fuji. These findings highlight that the different types of precipitation may be a key driver for isotopic variability of Antarctic snow.

Academic Significance and Societal Importance of the Research Achievements

氷床コアの酸素同位体比は古気温の指標として利用されている。観測結果から得られた経験則に基づいて古気温推定が行われているが、現在の経験則が過去に適応できる条件は未解明なままである。本研究の成果である「経験則が成り立つ物理的背景の解明」は、経験則を利用できる条件を明確にし、従来よりも信頼性の高い古気温推定を可能にする。気象観測の開始が遅れた南極内陸域では、温暖化影響の実態把握を行うために、酸素同位体比を使った長期気温データセットの作成が求められている。本研究は、そのニーズの実現に欠かせない課題の一つである。

Research Products

• [Int'l Joint Research] University of Wisconsin-Madison/Madison Area technical College(米国)
• [Int'l Joint Research] University of Oulu(フィンランド)
• [Int'l Joint Research] Oulu University(フィンランド)
• [Int'l Joint Research] University of Wisconsin-Madison(米国)
• [Int'l Joint Research] University of Oulu(その他の国・地域)
• [Journal Article] Comparison of ventilated and unventilated air temperature measurements in inland Dronning Maud Land on the East Antarctic Plateau (2021)
  • Author(s): Morino, S., N.Kurita, N.Hirasawa, H.Motoyama, K.Sugiura, M.A.Lazzara, D.Mikolajczyk, L.Welhouse, L.Keller, and G. Weidner
  • Journal Title: Journal of Atmospheric and Oceanic Technology Volume: 38 Issue: 12 Pages: 2061-2070
  • DOI: 10.1175/jtech-d-21-0107.1
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 東南極ドームふじ周辺における温暖化影響の実態把握 (2022)
  • Author(s): 森野祥平，栗田直幸, 亀田貴雄，本山秀明，平沢尚彦，Matthew A. Lazzara
  • Organizer: 日本気象学会2022年度春季大会
• [Presentation] Correction for relative heating errors in naturally ventilated air temperature measurements made from AWS on the Antarctic Plateau (2021)
  • Author(s): Morino, S., N.Kurita*, N.Hirasawa, H.Motoyama, K.Sugiura, M.A.Lazzara, D.Mikolajczyk, L.Welhouse, L.Keller, and G.Weidner
  • Organizer: Workshop on Antarctic Meteorology and Climate 2021
  • Int'l Joint Research
• [Presentation] Surface temperature changes at Dome Fuji region during the past four decades (2021)
  • Author(s): Morino, S., N.Kurita*, N.Hirasawa, H.Motoyama, K.Sugiura, M.A.Lazzara, D.Mikolajczyk, L.Welhouse, L.Keller, and G.Weidner
  • Organizer: The 12th symposium on Polar Science
  • Int'l Joint Research
• [Presentation] 宇宙線によるトリチウム生成について (2021)
  • Author(s): 栗田直幸*, S. Poluianov
  • Organizer: 第３回日本放射線安全管理学会・日本保健物理学会合同大会
  • Invited
• [Presentation] Spatial variation of 10Be in surface snow along the inland traverse route of Japanese Antarctic Research Expedition (2021)
  • Author(s): Horiuchi,K., S. Kato, K. Ohtani, N. Kurita, S, Tsutaki, F. Nakazawa, H. Motoyama, K. Kawamura, H. Tazoe, N. Akata, K. Yamagata, and H. Matsuzaki
  • Organizer: The 15th International Conference on Accelerator Mass spectrometry (AMS-15)
  • Int'l Joint Research
• [Presentation] Application of tritium tracer technique to the partitioning between clear-sky and synoptic precipitation over the Antarctic plateau, (2020)
  • Author(s): Naoyuki Kurita
  • Organizer: The 11th Symposium on Polar Science
  • Int'l Joint Research
• [Presentation] Recent spatial distributions of Tritium concentration in surface snow over East Antarctica (2019)
  • Author(s): Naoyuki Kurita
  • Organizer: Polar Science 2019
  • Int'l Joint Research