南極の氷床の減少は,氷床の基礎層の融解によって引き起こされる
H D Pritchard1, S R M Ligtenberg, H A Fricker
1British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge CB3 0ET, UK. h.pritchard@bas.ac.uk
Nature
|April 28, 2012
まとめ
南極の氷棚は,基礎層の融解が増加したため,主に風の変化により薄くなっています. この薄くなり,棚氷の補強が減り,氷河の流れが加速し,世界の海面上昇に寄与する.
科学分野:
- 氷河学 氷河学とは
- 気候科学 気候科学
- 海洋学 海洋学とは
背景:
- 南極の氷床の縁の氷河の加速が強くなっています.
- アイスシェルフの薄めと崩壊は,ブートレッシングを減少させ,氷河の流れを増加させる可能性があります.
- 氷床の薄まる原因と影響を理解することは,海面上昇を予測するために不可欠です.
研究 の 目的:
- 南極の氷棚の薄まりのパターンと原因を調査する.
- 氷床の薄まり,基礎層の融解,氷河の加速との関連を特定するため.
- 南極の氷床の質量バランスと海面に及ぼす気候変動の影響を評価する.
主な方法:
- 氷床の厚さの変化を測定するための衛星レーザー高度計.
- 表面フィーン層のモデリング.
- 海洋学および大気圧力の分析.
主要な成果:
- 基礎層の融解の増加によって引き起こされる氷床の薄まりの環南極のパターンを特定しました.
- 基礎層の融解が,南極の氷床の減少を誘発する主な要因であると推論した.
- 暖かい深水が海底の谷間を通って氷棚にアクセスする場所での最も高い稀薄化率が観察されています.
- 関連した風が,基礎層の融解と氷床の崩壊を促し,海洋の上昇と大気温暖化による.
結論:
- 気候強制,特に風の変化は,南極の氷床の質量バランスに大きく影響を与えます.
- 基礎層の融解による氷床の薄まりは,南極の氷床が世界の海面上昇に貢献することを制御する重要な要因です.
- これらのプロセスは,年単位から10年単位のスケールで動作します.
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