シナジスティック HNO3-H2SO4-NH3上層熱帯粒子形成
Mingyi Wang1,2,3, Mao Xiao4, Barbara Bertozzi5
1Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA.
Nature
|May 18, 2022
まとめ
トロポスフィアの上部の新粒子の形成は,窒素酸,硫酸,アンモニアの間の相乗反応によって引き起こされます. このプロセスは,雲凝縮核 (CCN) と氷核粒子の形成を大幅に強化します.
科学分野:
- 大気化学
- 雲の物理
- エアロゾール科学
背景:
- トロポスフィア上部の新粒子の形成は,雲凝縮核 (CCN) の主要な源である.
- この過程を駆動する特定の前駆体蒸気は,まだ十分に理解されていません.
- アンモニアは以前は雲の水滴によって取り除かれ,上層熱帯粒子形成における役割が制限されると考えられていた.
研究 の 目的:
- トロポスフィアの上部の条件下で,窒素酸,硫黄酸,アンモニアの新粒子の形成に対する相乗効果を調査する.
- これらの粒子の形成速度と成長メカニズムを決定する.
- 雲の凝縮核と氷の核形成粒子の役割を評価する.
主な方法:
- CERN CLOUD室で行われた実験で,上部熱帯圏の条件をシミュレートしました.
- 粒子形成率と成長の動態の分析
- モデルシミュレーションを使用して大気輸送と核化のプロセスを確認する.
主要な成果:
- 窒素酸,硫黄酸,アンモニアは,どの2つの構成要素の組み合わせよりもはるかに速い速度で,共作用して粒子を形成します.
- アンモニアと窒素酸の共同凝縮は,最小の硫酸でも,CCNサイズへの素早い粒子の成長を促します.
- これらのCCNは砂漠の塵に匹敵する非常に効率的な氷核粒子として機能します.
- モデルシミュレーションは,アジアのモンスーン中に効率的なアンモニア輸送を確認し,核形成と氷核粒子の拡散を推進します.
結論:
- HNO3-H2SO4-NH3のシネギスティックな核化のメカニズムは,上部トロポスフィアのCCN形成の主要な経路である.
- アンモニアは,特にアジアモンスーンのような上部熱帯粒子形成と成長において重要な役割を果たします.
- 形成された粒子は 氷の核を形成し 北半球の雲の性質や気候に影響を及ぼします
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