海洋氷床の崩壊が,西南極のスワイツ氷河盆地で進行している可能性がある
Ian Joughin1, Benjamin E Smith1, Brooke Medley1
1Polar Science Center, Applied Physics Lab, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698, USA.
Science (New York, N.Y.)
|May 14, 2014
まとめ
西南極氷床のスワイツ氷河は,海洋の融解により不安定な後退を開始している可能性があります. 現在の海面上昇は適度だが,数世紀以内に急速な崩壊が起こる可能性がある.
科学分野:
- 氷河学 氷河学とは
- 気候科学 気候科学
- 海洋学 海洋学 海洋学
背景:
- 西南極の氷床,特にスワイツ氷河は,深海盆地に位置しており,本質的に不安定に敏感です.
- 以前の研究では,Thwaites Glacierが南極の氷の損失の重要な構成要素であり,将来の海面上昇の潜在的な要因であると特定されています.
研究 の 目的:
- 海洋による融解に対するスワイツ氷河の感受性を数値モデルを用いて調査する.
- 氷河の不安定な後退が現在進行中かどうかを判断するためです.
主な方法:
- 数値的な氷床モデルの開発と応用.
- 現在の推定値に匹敵する海洋融解率でモデルを強制する.
- 氷河が海洋によって引き起こされる様々なレベルの融解に対する反応をシミュレートする.
主要な成果:
- モデルでは,海洋の融解による氷の減少が予測されたときに,観測された氷の減少を成功裏に再現した.
- サーウィッツ氷河による海面上昇のシミュレーションの貢献は,21世紀を通して年間0.25mm未満であり,その後も増加すると予測されています.
- シミュレーションは,おそらく最も低い融解シナリオを除いて,初期段階の崩壊が始まっていることを示唆しています.
結論:
- Thwaites Glacierは,海洋の融解に対して非常に敏感であり,将来の不安定性の可能性を示しています.
- 急速な崩壊の始まりは,海面上昇が年1mm以上と定義されており,融解速度に応じて,200年から900年以内に発生すると予測されています.
- 継続的なモニタリングと洗練されたモデリングは,スウェイツ氷河の潜在的な崩壊のタイムラインと,世界の海面への影響を正確に予測するために不可欠です.
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