西アフリカにおける持続的な干ばつに対する大西洋による強制的影響
T M Shanahan1, J T Overpeck, K J Anchukaitis
1Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA. tshanahan@jsg.utexas.edu
Science (New York, N.Y.)
|April 18, 2009
まとめ
西アフリカ 西アフリカ
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
- 気候科学 気候科学
- アフリカのモンスーン・ダイナミクス
背景:
- 西アフリカにおける持続的な干ばつが,20世紀以来記録されている.
- 大西洋海の表面温度に起因するが,20世紀以前の干ばつについてはほとんど解明されていない.
- 過去の干ばつの再構築は,現在の気候の変動に対する文脈を提供します.
研究 の 目的:
- 過去3千年におけるアフリカのモンスーンの自然の変化を復元する.
- 20世紀以前の干ばつの長さ,深刻さ,起源を理解するために.
- 最近の干ばつが長期の文脈で異常であるかどうかを評価する.
主な方法:
- ガーナのボスムトウィ湖の堆積物からの地形,同位体,地化学的証拠の分析.
- 過去のアフリカのモンスーンの変動性の再構築.
- 干ばつ間隔と大西洋海の表面温度変動の相関.
主要な成果:
- 何十年も何世紀も続く干ばつが,アフリカのモンスーンの特徴です.
- これらの深刻な干ばつ間隔は,大西洋の気温の自然な変動と関連しています.
- 近年の干ばつが,過去3千年と比較して異常ではない.
結論:
- アフリカのモンスーンは,長期にわたる深刻な干ばつを含む自然の変動を示しています.
- 過去の干ばつパターンは,より長く,より深刻な将来の干ばつの可能性を示唆しています.
- 長期的な変動を理解することは,西アフリカにおける気候変動への適応に不可欠です.
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