最後の氷河期における突然の気候変動の淡水強制

P U Clark¹, S J Marshall, G K Clarke

¹Department of Geosciences, Oregon State University, Corvallis, OR 97333, USA. clarkp@ucs.orst.edu

Science (New York, N.Y.)

|July 14, 2001

まとめ

大規模な氷床の変動により,淡水が転換され,北大西洋の深水形成に影響を与え,最後の脱氷期における気候の変動を引き起こした.

科学分野:

古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
氷河学氷河学とは
海洋学海洋学海洋学

背景:

最後の脱氷期には,千年規模の氷床のダイナミクスが顕著でした.
北米のローランタイド氷床の南端は,大幅な変動を経験した.
これらの変動は,北緯43度~49度くらいの間で発生した.

研究の目的:

ローレンティド氷床の限界変動が北大西洋の古海洋学に与える影響を調査する.
最後の脱氷期における気候の変動を駆動するメカニズムを理解する.
氷床による淡水パルスと海洋循環の関係を探求するため.

主な方法:

氷床の行動と海洋状態を再構築するために,古気候のプロキシデータの分析.
地質学的証拠に基づいた氷の縁の再構築.
淡水フロースの影響を評価するための海洋学モデリング.

主要な成果:

氷床の限界の変動は,北大西洋への淡水排出をエピソード的に増加させた.
大陸の排水はミシシッピ川の排水路からハドソン川やセントローレンス川に転用された.
淡水の流れの増加は,北大西洋の深水形成の減少と一致しました.

結論:

氷床のダイナミクスは北大西洋の循環と気候に大きな影響を与えました.
氷床の融解による淡水パルスは,急激な気候変動のメカニズムを提供します.
このメカニズムは,地球上の氷の量の中間期間の時期の特徴である可能性が高い.

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