南半球の気候の変動は北半球の氷床の地形によって引き起こされる
T R Jones1, W H G Roberts2, E J Steig3
1Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309-0450, USA.
Nature
|February 6, 2018
まとめ
西南極の気候の変動は,熱帯太平洋とのつながりが強かったため,最後の氷河期の2倍でした. この増加した変動性は,脱氷によって有意に減少した.
科学分野:
- 古代気候学
- 気候の動態
- 氷河地質学
背景:
- 北半球の大規模な氷床と最後の氷河期 (Last Glacial Maximum, LGM) 中の低温室効果ガスは,地球全体の気候を大幅に変化させた.
- 短期的な気候変動の主要な要因であるエルニーニョ・サザン・オシレーション (ENSO) は,氷河期の影響を受けていた.
- 氷河期間の高緯度気候の変動を理解することは依然として課題です.
研究 の 目的:
- LGMの間の高緯度気候の変動性を再構築し,定量化する.
- 氷河期間の熱帯気候と西南極の 遠隔接続を調査する
- 脱氷が気候の変動に与える影響を理解する.
主な方法:
- 西南極からの高解像度の水同位体記録の分析.
- 古代気候データを解釈するための気候モデルシミュレーション
- LGMの変動とホロセンの変動の比較
主要な成果:
- 西南極の年間から十年間の気候の変動は,ホロセーンと比較してLGMのほぼ2倍でした.
- 熱帯太平洋と西南極の間のより強いテレコネクションに関連していた.
- 北米の氷床の影響で 熱帯のコンベクションが変化して 遠隔接続が強化されました
- テレコネクションの強さは1万6千年から1万5千年前の脱氷期に急速に減少した.
結論:
- 高緯度気候の変動は,LGMの間に著しく増幅された.
- 北米の氷床の動態は,熱帯と高緯度の気候のつながりを調節する上で重要な役割を果たしました.
- 氷河解凍は,この増幅された気候の変動を大幅に減少させた.
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