南極の寒冷の逆転の間,熱帯アンデス氷河の大規模な前進
V Jomelli1, V Favier2, M Vuille3
1Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France.
Nature
|August 27, 2014
まとめ
熱帯アンデスの氷河は,南極の寒冷の逆転の間に,若いドライアスよりも,より進んだ. この研究は,アンデス山脈の氷河年代と気候反応を改訂し,気候変動の変動に対する異なる反応を強調しています.
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
- 氷河学 氷河学とは
- 気候モデリング
背景:
- ユング・ドライアス・スタディアル (12,800〜11,500年前) は,熱帯アンデスにおける氷河の進出と関連している.
- この解釈は,宇宙線曝露の年代測定に基づいているが,新しい生産率は時系列修正を必要とする.
研究 の 目的:
- 新しいコスモゲンヌクリドの生産率を用いて,熱帯アンデス氷河のクロノロジーを更新する.
- 南極寒の逆転と若きドライアス時代に北と南の熱帯アンデスにおける異なる氷河反応を調査する.
主な方法:
- コスモジェニックベリリウム-10 ((10) Be) とヘリウム-3 ((3) He) 氷河モレーンの年代測定.
- 熱帯アンデス全域で既存のモレーンと新しいモレーンの均質化 (10) Beと (3) He.
- 結合されたグローバル気候モデルを用いた一時的なシミュレーション.
主要な成果:
- New (10) Beのクロノロジーは,南極寒逆転 (14,500〜12,900年前) の南極熱帯アンデス北部の氷河の拡大が,若いドライアスより大きいことを示しています.
- 均質化された年代表は,北と南の熱帯アンデスに共通する氷河の行動を明らかにします.
- モデルシミュレーションは,氷河の行動と大西洋南極の転覆循環の変動性とCO2濃度とを関連付けています.
結論:
- 熱帯アンデス川の氷河は,南極の寒冷逆転期における寒冷条件に対して,若いドライアス期よりも強く反応した.
- 北部のアンデス川の氷河は,地域温暖化により,若いドライアス時代に後退し,南部の氷河は,漸進的な温暖化により後退した.
- 氷河の振る舞いは,過去の気候の変動に対する明確な地域的な気候反応を示しています.
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