全世界の大気中のヒドロキシル化合物の年間変動は小さい
S A Montzka1, M Krol, E Dlugokencky
1NOAA Earth System Research Laboratory, Boulder, CO 80305, USA. stephen.a.montzka@noaa.gov
まとめ
炭酸水素 (OH) ラジカルで測定された地球大気の酸化能力は,以前考えられていたよりも年差が小さいことが示されています. これは,以前のメチルクロロフォーム (CH3CCl3) のデータ解釈とは対照的に,大気は汚染と自然の変化に抵抗性があることを示唆しています.
科学分野:
- 大気化学 大気化学
- 環境科学 環境科学
背景:
- グローバルな大気酸化能力は,主にヒドロキシル (OH) ラジカルによって決定されます.
- メチルクロロフォーム (CH3CCl3) の測定は,OH濃度を診断し,年間間の変動を推論するために使用されています.
- 以前の解釈は,大気中の酸化能力が干渉に対して有意に敏感であることを示唆していた.
研究 の 目的:
- 世界平均OH濃度の年間変動性を再評価する.
- 大気中の酸化能力の乱に対する回復力を評価する.
- 1998年以降のCH3CCl3データを用いてOHの変動率の推定を精密にするために.
主な方法:
- メチルクロロフォーム (CH3CCl3) 測定の分析,特に1998年以降の測定.
- モントリオール議定書によるCH3CCl3の減少した大気梯度を利用する.
- メタンやその他の微量ガス測定とグローバル光化学モデルとの比較.
主要な成果:
- OH濃度の年間変動が著しく小さいことが推論された.
- グローバルなOH濃度は,波動に対して良好なバッファリングされているようです.
- 精製されたOHの変動性は,他の大気測定とモデル計算と一致しています.
結論:
- 地球の大気は,以前に推定されたよりも,酸化能力においてより高い安定性を示しています.
- モントリオール議定書のCH3CCl3測定への影響は,OHの変動性評価を改善しました.
- グローバルOHは頑丈で,短期的な環境変動に弱い.
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