海洋境界層における反応性窒素の急速な循環
Chunxiang Ye1, Xianliang Zhou1,2, Dennis Pu2
1Wadsworth Center, New York State Department of Health, Albany, New York, USA.
Nature
|April 12, 2016
まとめ
粒子窒素の光分解は,海洋の大気中の窒素酸を素早くリサイクルします. この過程は特に海上では重要であり,大気中の酸化物質とエアロゾールの主要な源として機能します.
科学分野:
- 大気化学
- 環境科学
- 地化学
背景:
- 窒素酸化物 (NOx) は大気中の酸化物質とエアロゾールに不可欠です.
- 窒素酸 (HNO3) はNOxの恒久的な吸収源と考えられていたが,観測結果はモデルと矛盾している.
- NOxのリサイクルを説明するために"再毒化"プロセスが提案されているが,そのメカニズムは不明である.
研究 の 目的:
- トロポスフィアの窒素酸化物へのリサイクルメカニズムを調査する.
- NOx再生に対する粒子の窒素光分解の貢献を定量化する.
- 海洋地域におけるこのリサイクルプロセスの世界的な重要性を評価する.
主な方法:
- 大気データを収集するために北大西洋上空で航空機の測定を行いました.
- 微粒子の窒素の光分解速度を研究する実験室での実験.
- 化学プロセスをシミュレートするために,マスター・ケミカル・メカニズムを使用するボックス・モデル計算.
主要な成果:
- 海の境界層における粒子の窒素光分解により,窒素酸 (HONO) と窒素酸化物 (NOx) の急速なリサイクルが証明されている.
- 粒子の窒素の光分解速度は,ガス状窒素酸の光分解速度の2倍以上で,かなり高い.
- モデルの計算によると,粒子の窒素光分解は,海洋環境で観察された昼間のHONOとNOxのレベルを維持しています.
結論:
- 粒子の窒素光分解は,特に海上では,熱帯圏の窒素酸化物の重要な源である.
- このリサイクルメカニズムは,大気中の酸化物質と二次エアロゾールの形成を世界的に促進します.
- この発見は,窒素酸が永続的な NOx 吸収源であるという伝統的な見解に異議を唱える.
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