1998年のオクラホマ州とテキサスの干ばつにおける海面温度と土壌水分フィードバックの役割
1National Centers for Environmental Prediction, Camps Springs, Maryland 20746, USA.
Nature
|December 29, 2000
まとめ
1998年のオクラホマ州とテキサスの干ばつが,海面温度異常と大気循環によって引き起こされた. 蒸発の減少のような地域的なフィードバックは,より大きな気象システムが介入するまで,干ばつを維持しました.
科学分野:
- 気候学 気候学
- 大気科学 大気科学
- 気象学 気象学 気象学
背景:
- 1998年のオクラホマ州とテキサスの干ばつが",ダストボウル"のレベルに達したが,他の地域ではエルニーニョの予測が成功した.
- 海面温度異常に対する熱帯外の大気反応は,熱帯の反応よりも予測が難しい.
研究 の 目的:
- 1998年のオクラホマ州とテキサスの極端な熱帯外気候の起源と持続を調査する.
- 干ばつ開発におけるグローバル・テレコネクションと地域的なフィードバックの役割を区別する.
主な方法:
- グローバルおよび地域の大気モデルを用いた機械的実験.
- 地域的な気候フィードバックメカニズムの孤立.
主要な成果:
- 海面温度異常と好ましい大気循環が1998年4月~5月の干ばつを引き起こした.
- 蒸発と降雨の減少は,ポジティブなフィードバックループを作り,6月から8月の干ばつを維持しました.
- 干ばつが秋に終わり,より強い気象システムが地域の土壌水分フィードバックを克服した.
結論:
- 海面温度異常と大気パターンは,熱帯外の干ばつの主要な要因です.
- 地域的な陸地-大気フィードバックは,干ばつ持続に大きく貢献しています.
- 物理的プロセスを組み込む数値モデルは,地域の気候予測を改善することができます.
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