イソプレン排出によって抑制された森林における新粒子の形成
Astrid Kiendler-Scharr1, Jürgen Wildt, Miikka Dal Maso
1Institut ICG-2, Troposphäre. a.kiendler-scharr@fz-juelich.de
Nature
|September 18, 2009
まとめ
イソプレンは,一般的な植物排出物であり,ヒドロキシル基と反応することで,新しい粒子の形成を大幅に抑制します. この発見は,エアロゾールイベントの季節的変動を説明するのに役立ち,気候モデルに影響を与える可能性があります.
科学分野:
- 大気化学 大気化学
- 気候科学 気候科学
- 環境科学 環境科学
背景:
- 植生からの揮発性有機化合物 (VOC) は,有機エアロゾール形成と気候の放射性強制に影響を与えます.
- 北極地域におけるモノターペンの排出は,新しい粒子の形成と負の放射線強制と関連しています.
- エアロゾールの成長率の季節的変動は,モノテルペン排出量と相関しており,夏にピークに達する.
研究 の 目的:
- イソプレンの新粒子の形成に対する影響を調査する.
- 粒子核形成に対するイソプレンの作用のメカニズムを理解するために.
- 気候モデリングとエアロゾールの放射性強制に対するイソプレンの役割の影響を評価する.
主な方法:
- 植物室を用いたシミュレーション実験.
- イソプレン濃度とVOC混合物の制御された変動.
- 粒子の数の濃度とOH基の反応性との相関の分析.
主要な成果:
- イソプレンは新しい粒子の形成を著しく阻害し,濃度が高ければ抑制が増加します.
- 阻害は主にイソプレンがヒドロキシル基 (OH) との高い反応性による.
- 観測された抑制パターンは,エアロゾール核化イベントの季節的変動と一致し,夏のイベントが少ないことを説明します.
結論:
- イソプレンのOHとの反応性は,新しい粒子の形成を抑制する上で重要な役割を果たします.
- 気候変動によるイソプレンの豊富性の増加は,新しい粒子形成の可能性を減少させる可能性があることを示唆している.
- この減少は,エアロゾールの負の放射線強制効果を弱め,気候予測に影響を与える可能性があります.
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