雲の滴によって媒介される有機酸の普遍的な大気産生
B Franco1,2, T Blumenstock3, C Cho4
1Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich, Jülich, Germany. bfranco@ulb.ac.be.
Nature
|May 13, 2021
まとめ
フォルマルデヒドはメタネジールを介して雲の中でアリ酸に変換されます. この多相経路は 大気中のアリ酸を大幅に増加させ 雲の酸性に影響を与え 気候モデルの不一致を調整します
科学分野:
- 大気化学
- 雲の物理
- 気候モデリング
背景:
- 大気中の酸度には二酸化炭素と有機酸が影響する.
- アリ酸は雲の滴の核形成と雨水の酸性において重要な役割を果たします.
- 現在の化学・気候モデルでは 大気中のキノコ酸を過小評価しています
研究 の 目的:
- 大気条件下でホルムアルデヒドをアリ酸に変換する経路を調査する.
- この経路が大気中のアリ酸の総負荷に与える影響を定量化する.
- モデル予測とミツバチ酸の量度との差異を調整する.
主な方法:
- フォーマルデヒドの多相変換を研究するために大気室実験が行われた.
- 熱い雲の水滴におけるメタネジール (ホルマルデヒドの水分化形態) の役割が調査された.
- メタネジール酸化によるアリ酸の産生を推定するために,化学気候モデルを使用した.
主要な成果:
- フォーマルデヒドは,メタネジールを含む多相経路で,効率的にガス状のアリ酸に変換されます.
- 熱い雲の水滴では,メタネジオールは急速な排気が起こりますが,ゆっくりと脱水します.
- メタネジールのガス相酸化は,他のすべての既知の源を合わせたよりも最大4倍ものアリ酸を生成します.
結論:
- ダイオールメカニズムは現在の気候モデルにおける アシドの過小評価を説明しています
- この経路は大気中のアリ酸を大幅に増加させ,雲と雨水の酸度を0.3pH単位まで上昇させます.
- このメカニズムは他のアルデヒドにも適用され,大気中の他の有機酸の濃度が高いことを説明する可能性がある.
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