ボリビアの氷の核からの2万5千年の熱帯気候の歴史
Thompson1, Davis, Mosley-Thompson
1L. G. Thompson, M. E. Davis, K. A. Henderson, V. S. Zagorodnov, J. F. Bolzan, Byrd Polar Research Center, Department of Geological Sciences, The Ohio State University, Columbus, OH 43210, USA. E. Mosley-Thompson, Byrd Polar Research Center, D.
Science (New York, N.Y.)
|December 4, 1998
まとめ
ボリビアの氷芯は,後期氷河期における熱帯気候の変化を明らかにしています. 低い塵と酸素同位体は,より湿った環境と気温の変化を示し,気候現象の大気要因を示唆しています.
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
- 熱帯気候のダイナミクス
背景:
- 氷芯は,過去の気候条件の重要なアーカイブです.
- 熱帯地域は,世界の気候パターンに関するユニークな洞察を提供します.
- 以前の研究では,地球規模の気候の傾向が確認されていますが,熱帯の記録はあまり一般的ではありません.
研究 の 目的:
- 氷河期末期の熱帯気候の変動を,氷河核データを用いて再構築する.
- 熱帯の急激な気候現象の原因を調査する.
- 熱帯気候のシグナルを極域のシグナルと比較する.
主な方法:
- ボリビアのサジャマ山の氷芯の回収と分析.
- カーボン14年代測定法 年代測定法 年代測定法
- 温度と降水量の変化を推測するための酸素同位体分析.
- 大気条件と乾燥度を評価するための塵濃度測定.
主要な成果:
- サジャマの氷芯は,後期氷河期まで続く,炭素14日付の熱帯記録を提供している.
- 酸素の同位体比は,ホロセンの初期から最後の氷河期最大期まで大幅に減少した.
- ユング・ドライアス型イベントは,突然の始まりと終わりを示し,大気の要因を示した.
- 地域氷の蓄積は,後期氷河期,脱氷期,過去3000年の間に増加し,より高い古湖レベルと相関しています.
- サジャマの氷河は,ホロセンの氷と比較して,塵の含有量が著しく低く,より湿った状態を示しています.
結論:
- サジャマの氷芯記録は,極地記録を補完する貴重な熱帯気候データを提供しています.
- 大気中のプロセスが急激な気候変化を引き起こした可能性があり,若いドライアスのようなイベントも含まれています.
- 地域の湿度の増加と雪の覆いは,熱帯アンデスで湿った時期を特徴づけた.
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