アマゾンの干ばつのリスクが高まるのは,エアロゾール汚染の減少による
Peter M Cox1, Phil P Harris, Chris Huntingford
1School of Engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, UK. p.m.cox@exeter.ac.uk
Nature
|May 10, 2008
まとめ
アマゾン熱帯雨林の気候変動は懸念されています. アマゾニア西部における降雨量の減少は,大西洋海の表面温度グラデーションと相関しており,将来の干ばつリスクを示唆しています.
科学分野:
- 気候科学 気候科学
- トロピカル気象学 トロピカル気象学
- 生態系のダイナミクス
背景:
- アマゾンの熱帯雨林は,大気循環と水循環に影響を及ぼし,世界の気候規制に不可欠です.
- 大量の炭素を貯蔵し,世界の一次生産性に寄与する.
- 森林伐採と地球温暖化に対する森林の回復力は,予測される乾燥傾向のために大きな懸念事項です.
研究 の 目的:
- 2005年の干ばつを背景にアマゾンの気候予測を分析する.
- アマゾンの降雨量と大西洋の海面温度 (SST) の関係を調査する.
- 気候モデルの精度と将来の予測に対するエアロゾールの影響を評価する.
主な方法:
- エアロゾール効果を含むGCMを用いた気候予測の分析.
- アマゾニア西部における乾季の降雨量の相関関係と,赤道的な大西洋北から南のSSTグラデント.
- 観測された関係に基づく21世紀の気候シナリオのシミュレーション.
主要な成果:
- アマゾニア西部における乾季の降雨量の減少と,大西洋のN-S SSTグラデントとの間に強い相関が見られた.
- 気候モデルは,エアロゾール効果を含めると,歴史的な降雨-SST関係と多十年間の変動を正確に再現しました.
- 将来の気候シミュレーションでは,2005年と同様の干ばつの頻度が増加すると予測されています.
結論:
- 大西洋北南 SSTの傾斜は,アマゾンの乾季の降雨変動の主要な要因である.
- 北半球のエアロゾール汚染の削減は,アマゾンの干ばつ状態を悪化させると予測されています.
- これらの変化は,アマゾンの生態系,地球規模の炭素循環,および純一次生産性に対して重大な影響を及ぼします.
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