蒸気圧の減少による世界の水使用効率の飽和
Fei Li1,2, Jingfeng Xiao3, Jiquan Chen2
1Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot 010010, China.
まとめ
世界生態系の水利用効率 (WUEeco) は2001年以降増加していない. 気候変動による蒸気圧赤字 (VPD) の上昇は,大気中の二酸化炭素 (CO2) の増加による植物用水の恩恵を相殺している.
科学分野:
- 地球システム科学
- エコロジー
- 気候科学
背景:
- 生態系の水利用効率 (WUEeco) は,炭素の吸収と蒸発の比率である.
- 大気中の二酸化炭素 (CO2) の上昇は,WUEecoを増加させると予想されています.
- WUEecoに対するCO2と気候変動の相互作用は十分に理解されていません.
研究 の 目的:
- WUEecoの世界的な傾向を調査する.
- 大気中のCO2の上昇と気候変動が WUEに与える影響を決定する.
- 地球の炭素と水循環の 将来の変化を予測する
主な方法:
- 機械学習の手法を使って 拡大した推定値です
- 2001年以降の全世界のFLUXNET観測の分析
主要な成果:
- グローバルWUEecoは2001年以降増加していない.
- 蒸気圧赤字 (VPD) の増加は光合成を抑制し,ETを増加させた.
- 温度上昇とVPDは,ESの重要な調節因子であり,おそらく口腔伝導性よりも重要です.
結論:
- 気候変動,特にVPDの増加は,WUEecoに対する CO2の上昇の期待される恩恵を相殺する.
- 将来のVPDの増加は,地上の炭素と水のサイクル間の結合を大幅に変更する可能性があります.
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