小氷河期の冷却による熱帯太平洋の動的刺激とENSOの変動
Gerald T Rustic1, Athanasios Koutavas2, Thomas M Marchitto3
1Department of Engineering Science and Physics, College of Staten Island, City University of New York, Staten Island, NY 10314, USA. Doctoral Program in Earth and Environmental Sciences, Graduate Center of the City University of New York, New York, NY 10016, USA. grustic@ldeo.columbia.edu.
まとめ
ガラパゴス島の堆積物からの古気候記録は,中世の気候異常と小さな氷河期における熱帯太平洋の動態の変化を明らかにしています. ミレニアム半ばのシフトは,エルニーニョ・サザンオシレーションの活動と弱まったグラデーションを示しています.
科学分野:
- 古代海洋学
- 気候科学
- 海と大気の動態
背景:
- 過去の熱帯太平洋の動態を理解することは 気候モデリングに不可欠です
- 中世気候異常期 (MCA) と小氷河期 (LIA) の東方赤道太平洋の古気候データは限られている.
研究 の 目的:
- 過去の海面温度,エルニーニョ・サザンオシレーション (ENSO) 活動,熱帯太平洋のゾナルグラデーションを再構築する.
- MCAとLIAの間,海洋-大気循環のシフトを調査する.
主な方法:
- ガラパゴス諸島からの堆積物分析
- 海面温度とENSO活動に関する古海洋学プロキシの再構築.
主要な成果:
- ミレニアムシフト (MMS) は西暦1500年~1650年頃に発生し,濃縮されたENSOと強いゾナルのグラデントから増幅されたENSOと弱いグラデントへと移行した.
- MMSは,LIAの最も深い冷却と一致し,南向きの熱帯間の収束地帯のシフトによって引き起こされた可能性が高い.
- MCAピーク (西暦900年−1150年) は,東太平洋の温暖な条件によって特徴づけられ,持続的なラニーニャパターンの概念に挑戦しました.
結論:
- 東方赤道太平洋は,MCAとLIAの間に海洋-大気循環に大きな変化を経験しました.
- 気候変動はENSOの活動と 熱帯間の収束地帯の位置の変化と関連しています
- 過去の気候再構築は,重要な古気候間隔の熱帯太平洋の行動に関する既存のパラダイムに挑戦しています.
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