純粋な生物学的粒子のイオン誘発核化
Jasper Kirkby1,2, Jonathan Duplissy3,4, Kamalika Sengupta5
1Goethe University Frankfurt, Institute for Atmospheric and Environmental Sciences, 60438 Frankfurt am Main, Germany.
Nature
|May 27, 2016
まとめ
新しい研究により,高度に酸化したバイオジェニック蒸気は,硫酸なしでエアロゾール粒子を形成することが示されています. 銀河の宇宙線が このイオン誘発核形成過程を大きく促進し 雲の形成に影響を与えます
科学分野:
- 大気 化学 と 物理
- 気候科学
- エアロゾール科学
背景:
- 大気中のエアロゾールは気候に影響しますが,雲の凝縮核 (CCN) 生産におけるその形成と役割は完全に理解されていません.
- 硫酸は従来,粒子核化に欠かせないと考えられており,イオンは小さな役割を果たしている.
- 以前の研究では 硫酸なしで有機粒子の形成が示唆されていましたが 汚染が懸念されていました
研究 の 目的:
- 大気条件下での硫酸の欠如で,高度に酸化された生物学的蒸気からエアロゾール粒子の形成を調査する.
- この核形成の過程における 銀河の宇宙線からのイオンの役割を 決定する.
- 有機分子相互作用に関する理論的計算を裏付ける実験的証拠を提供すること.
主な方法:
- 高酸素化分子 (HOMs) を生成する α-ピネンのオゾン分解を研究するために大きな大気シミュレーション室を使用した.
- ニュートラルな条件下での粒子核化率と,銀河宇宙線からのイオンの影響を受けた条件を比較した.
- HOMクラスタの結合エネルギーを評価するために量子化学計算を行いました.
主要な成果:
- 硫酸を必要とせずに,高度に酸化された生物学的蒸気 (HOMs) からエアロゾール粒子の形成が実証された.
- 中性核形成と比較して,イオン誘発核形成による核形成率の有意な増加 (大きさの1〜2度) を観察した.
- 実験結果は,HOMクラスター結合エネルギーの理論的計算と一致した.
結論:
- 純粋な有機粒子のイオン誘発核化は,大気中のエアロゾール形成の重要な経路です.
- このプロセスは,硫酸濃度が低い地上の環境で広く使用できます.
- 硫酸の重要な役割に関する伝統的な見解に異議を唱え,エアロゾール形成における生物学的VOCとイオンの重要性を強調しています.
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