氷河期の終焉の結末である
Hai Cheng1, R Lawrence Edwards, Wallace S Broecker
1Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA.
Science (New York, N.Y.)
|October 10, 2009
まとめ
中国のスタラグミットからのアジアモンスーンの降水記録は,過去の氷河終結と正確に相関しています. これは,北半球の夏の太陽熱が氷河期の終結を誘発し,世界の気候とCO2レベルに影響を与えることを確認しています.
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
- 地質化学 地質化学
- 四次科学とは四次科学である.
背景:
- 過去の氷河期の終結を理解することは,将来の気候変動を予測するために極めて重要です.
- アジアモンスーン (AM) は,世界の気候動態において重要な役割を果たしています.
- 古気候記録の正確な相関は,過去の気候現象を再構築するために不可欠です.
研究 の 目的:
- 過去の氷河期におけるアジアモンスーンの降雨を,スタラグミット記録を用いて特徴づけること.
- AM記録を他の古気候アーカイブ (氷核,海洋堆積物) と正確に相関させるため.
- 氷河の終結の引き金とメカニズムを調査する.
主な方法:
- 中国サンバオ洞窟のスタラグミットの230Th年代付け.
- スタラグミットからの酸素同位体記録の分析.
- スタラガミットデータと氷芯と海洋沈殿物の記録の相関.
主要な成果:
- サンバオ洞窟からの酸素同位体記録は,過去4つの氷河終結の詳細なAM降水データを提供しています.
- AM記録は,氷芯と海洋沈殿物のデータと正確に相関し,イベントのタイミングを確立します.
- 観測結果は,北半球の夏の太陽照射が氷床の退却の初期トリガーであることを支持しています.
結論:
- 氷河の終結は,北半球の夏の太陽照射によって開始されます.
- 北大西洋に流入する融水は,海洋と大気循環を変化させ,地球温暖化に影響を及ぼします.
- CO2と太陽熱の上昇は,氷床の衰退を促し,海面とCO2の間の潜在的なポジティブなフィードバックをもたらします.
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