最後の氷河期における海洋フィードバックによる軌道強制の増幅をシミュレートした
M Khodri1, Y Leclainche, G Ramstein
1LSCE, CF-Saclay, 91191, Gif sur Yvette, France. khodri@lsce.saclay.cea.fr
Nature
|March 30, 2001
まとめ
11万5千年前,低夏の太陽放射線が氷河期を誘発した. 海洋のフィードバックは,この冷却を拡大し,高緯度で雪を増やし,最後の氷河期の始まりを説明しました.
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,古代気候学 (paleoclimatology) とは
- 気候モデリング
背景:
- ミランコビッチの理論では,夏の日差しの減少が過去の氷河期を誘発したと仮定しています.
- 以前の気候モデルでは,インソレーション強制のみを用いて最後の氷河期をシミュレートできませんでした.
研究 の 目的:
- 最後の氷河期における軌道強制力の増幅における海洋-大気フィードバックの役割を調査する.
- 海洋-大気モデルを組み合わせて氷床の形成をシミュレートする.
主な方法:
- 完全に結合された海洋大気モデルを利用した.
- 最後の氷河期に係る太陽照射の変化でモデルを強制した.
主要な成果:
- 重要な氷床の場所での恒常的な雪の積もりを成功裏にシミュレートしました.
- 海洋のフィードバックが高緯度の冷却を引き起こすことを実証しました.
- 極に向かって大気中の水分輸送が増加したことを示した.
結論:
- 海洋のフィードバックは,弱小の軌道強制を拡大し,氷河化の開始に不可欠です.
- モデルの結果は,過去の氷床の地質学的証拠と一致しています.
- このメカニズムは,植物の変化によって潜在的に増幅された最後の氷河期の始まりを説明します.
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