Background factors causing significant basal melting in the Shirase Glacier region, East Antarctica

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K12132
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: National Institute of Polar Research (2021-2023); Hokkaido University (2020)
• Principal Investigator: Hirano Daisuke 国立極地研究所, 南極観測センター, 助教 (30790977)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 東南極 / 白瀬氷河 / 氷床海洋相互作用 / 暖水流入 / 棚氷底面融解

Outline of Final Research Achievements

A series of ice-ocean interaction processes in the Shirase Glacier region, East Antarctica, with warm water inflow from offshore, is identified by integrating the results from in-situ and satellite observations and coupled ocean-sea ice-ice shelf modeling. The presence of offshore clockwise circulation and slope jets are considered background factors for the strong ice-ocean interaction in the region. Comparison with other East Antarctic glaciers (Totten Glacier) reveals that while there are regional differences in the bathymetry and ocean circulation around the glacier, the presence of clockwise circulation (gyre and standing eddies) that efficiently transports offshore warm water towards the Antarctic continent is one of the key background factors on the open ocean leading to localized warm-water inflows into the cold East Antarctic continental shelf and then intense basal melting of the ice shelf.

Free Research Field

極域海洋学・海洋物理学

Academic Significance and Societal Importance of the Research Achievements

南極氷床の質量損失を加速させている主要因は「周囲の海」による棚氷底面の融解促進であり、精度の高い海水準変動の将来予測には氷床質量損失に対する海洋の本質的役割の理解が不可欠である。西南極と比べ、東南極では特に沖合起源暖水による棚氷底面融解プロセスやその背景要因に関する知見は乏しく、理解が大きく遅れていたが、暖水流入を伴う東南極・白瀬氷河域での顕著な底面融解プロセスとその背景要因を提示した本課題の成果はIPCC第６次報告書にも引用されるなど、東南極氷床―海洋相互作用研究の進展に貢献した。