南極大陸周辺の氷床が溶けている.
E Rignot1, S Jacobs, J Mouginot
1Department of Earth System Science, University of California, Irvine, CA 92697, USA. erignot@uci.edu
まとめ
南極の氷棚の融解,主に基礎融解は,南極で最も大きな消去プロセスです. 暖かい穴を持つ小さな氷棚は,この融解に不均衡に寄与し,海洋の熱力強制が顕著であることを示しています.
科学分野:
- 氷河学 氷河学とは
- 海洋学 海洋学とは
- 気候科学 気候科学
背景:
- 南極の氷棚は,氷床の安定性を調節する上で重要な役割を果たしています.
- 氷床の質量バランスを理解することは,海面上昇の予測に不可欠です.
研究 の 目的:
- 南極の氷棚の融解速度と質量バランスを定量化するために.
- アイスシェルフの消去の主な要因と場所を特定する.
主な方法:
- 容量流動の分散データ (2007-2008) と表面積 (1979-2010) と薄め (2003-2008) の記録を比較する.
- 異なるシェルフタイプの氷河における基礎融解速度とカルトフルースの分析.
主要な成果:
- 基礎溶解量 (年間1325 ± 235 Gt) は,分娩流量 (年間1089 ± 139 Gt) を大幅に上回り,溶解を支配的なアブレーションプロセスとして確立しています.
- 大規模な氷棚 (Ross,Filchner,Ronne) は,純溶融に最小の (15%) しか貢献しないが,より小さい東南太平洋の暖かい空洞の棚 (8%の面積) は,溶融水の半分を占めている.
- 6つの東南極の氷棚の溶融/面積の高い比率は,それらの接地線で強い,特徴のない海洋熱力強制を示唆しています.
結論:
- アイスシェルフの融解は,南極の氷の減少の主な要因である.
- 小規模で暖かい穴の氷棚は,南極の融解に重大な貢献をしている.
- 文書化されていない海洋熱力強制は,東南極の氷棚に影響を与える可能性が高い.
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