大変変性の高いエルニーニョ-南方振動は,ホロセーン全体で発生しました

Kim M Cobb¹, Niko Westphal, Hussein R Sayani

¹School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA. kcobb@eas.gatech.edu

Science (New York, N.Y.)

|January 5, 2013

まとめ

エルニーニョ-南方振動 (ENSO) は7000年以上にわたって高い変動を示しています. 現在の気候モデルは,自然的な気候の変動性による強制的なENSO変化を検出するのに苦労する可能性があります.

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
気候変動のダイナミクス
海洋学海洋学海洋学

背景:

エルニーニョ・サザン・オシレーション (ENSO) は,毎年,世界の気候パターンに大きな影響を及ぼします.
人為的な温室効果ガス排出に対するENSOの感受性は依然として不確実である.
フォッシングに対するENSOの反応を理解することは,気候変動の予測にとって極めて重要です.

研究の目的:

化石サンゴの記録を使用して,ENSOの長期的な変動性を分析する.
ENSOの過去自然現象への対応を評価し,モデル予測と比較する.
ENSOに対する人類による影響の潜在的検出性を調査する.

主な方法:

ENSOの過去7000年の活動に関する化石サンゴの再構築を用いた.
ENSOの重要な地域であるNorthern Line Islandsのデータにフォーカスした分析.
古代気候 ENSOのバリエーションを,楽器記録と気候モデルの出力と比較した.

主要な成果:

化石のサンゴは,過去7000年にわたって非常に変動するENSO活動を示しています.
ENSOのバリエーションの系統的な傾向は見つかりませんでしたが,これは一部の太陽照射型モデルと矛盾しています.
20世紀のENSOのバリエーションは高いものの,古気候記録では前例のないものではありません.

結論:

長期的なENSOの変動は大きく,気候変動のシグナルを隠す可能性がある.
ENSOに対する人為的影響の検出は,高い内部変動の背景で困難である可能性があります.
ENSOの過去の行動は,外部からの強制への回復力と複雑な反応を示唆しています.

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