南洋の起源は,脱氷期間の大西洋熱ハリン循環の再開のためである
1Institut für Meteorologie, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany. gregor.knorr@dkrz.de
Nature
|August 2, 2003
まとめ
南洋の温暖化は,融水ではなく,脱氷の間に大西洋循環の強化を開始しました. この発見は,北半球と南半球の気候変化を調和させ,氷河期間の状態への帰還を説明しています.
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
- 海洋学 海洋学 海洋学
- 気候モデリング
背景:
- 脱氷は,グリーンランドの温暖化に先行する南半球温暖化を示しています.
- 北大西洋への融水排出は,深い水の形成を阻害すると考えられている.
- 大西洋の熱ハリン循環 (THC) は,脱氷期中に強化され,氷河期から氷河間期に移行した.
研究 の 目的:
- 南洋の温暖化と海氷の縮小が,大西洋のTHCに及ぼす影響を調査する.
- 脱氷時のTHC強化の主な要因を決定する.
主な方法:
- 3次元海洋循環モデルを利用した.
- 南洋の漸進的な温暖化とそれに伴う海氷の退却をシミュレートした.
主要な成果:
- 南洋の温暖化は,氷期間のTHCモードの突然の再開を引き起こした.
- インド洋と太平洋経由で大西洋への大量輸送の増加が鍵でした.
- この温暖化効果は,融水排出の反対の影響を相殺し,克服した.
結論:
- 南洋の温暖化は,THCの氷河間モードのトリガとして作用します.
- このメカニズムは,脱氷期における半球気候変化の統一的な説明を提供する.
- 発見は,既存の古気候のプロキシ記録と一致しています.
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