プレオセンのパラドックス (恒常的なエルニーニョのメカニズム)
A V Fedorov1, P S Dekens, M McCarthy
1Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA. alexey.fedorov@yale.edu
まとめ
初期のプレオセンの温暖化は,恒常的なエルニーニョによって引き起こされた. 氷河と寒い上流がこれを終わらせ,傾斜サイクルを拡大し,地球温暖化の冷却につながった.
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
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
背景:
- プレオセンの初期 (500万~300万年前) は,地球全体の気温が今日より高かった.
- この時期,熱帯ではエルニーニョが連続していた.
- 外部気候の原動力は,現在の条件に似ていた.
研究 の 目的:
- プレオセンの初期の温暖な気候条件の終焉を調査する.
- 恒常的なエルニーニョから断続的な出来事への移行を説明してください.
- 海面温度と氷の量における傾斜周期の増幅を分析する.
主な方法:
- 過去の海面温度と氷の量を再構築するために,古気候プロキシの分析.
- 気候現象と傾斜周期の相関.
- 海洋-大気相互作用とフィードバックメカニズムのモデリング.
主要な成果:
- 北部の大陸の氷河と低緯度の上流地帯の冷たい地表水の出現は,恒常的なエルニーニョの終わりを示した.
- 赤道海面温度と地球上の氷の量における斜率サイクルが拡大した.
- 赤道海面温度の変化は,氷の量変化に数千年先行した.
結論:
- 約300万年前,海洋熱線が重要な値に達したことで,傾斜サイクルを拡大するフィードバックが開始されました.
- 海-大気と氷のアルベドのフィードバックは,気候サイクルを拡大した.
- 氷河の融解や熱帯層の深まりなどの将来の変化は,プレオセンのような温暖な条件を早期に回復させる可能性がある.
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