トロポスフィアの上部とストラトスフィアの下部におけるイオン核化による粒子形成
S-H Lee1, J M Reeves, J C Wilson
1Department of Engineering, University of Denver, Denver, CO 80208, USA. shanlee@du.edu
まとめ
超細粒子の濃度は,大気の上層部で意外と高かった. イオン誘発核化はこれらの大気粒子の主要な源であり,雲の形成と気候に影響を与える.
科学分野:
- 大気化学 大気化学
- エアロゾール科学は,
- 気候科学 気候科学
背景:
- 超細粒子 (UFPs) は,上層熱帯圏と下層平流圏 (UTLS) で一般的です.
- UTLSにおけるUFPの形成メカニズムと発生源は,まだ完全に理解されていません.
- 以前の研究では,この地域における重要なUFP源としてのイオン誘発核化を完全に説明できませんでした.
研究 の 目的:
- UTLSにおける超細粒子の形成と成長を調査する.
- UFP生産におけるイオン誘発核化の役割を決定する.
- 大気中のエアロゾールに対するこの核形成プロセスの世界的な重要性を評価する.
主な方法:
- イオン誘発核形成をシミュレートする数値モデルを使用した.
- 測定された熱力学データによる制限モデルシミュレーション.
- 組み込まれた観測された大気中の主要な種の濃度.
主要な成果:
- モデルのシミュレーションは,観察されたUFP数の濃度とサイズ分布を正確に再現しました.
- イオン誘発核化は,UTLSの様々な緯度におけるUFP観測と一致することが判明しました.
- 粒子の形成と成長は,十分な太陽放射線と,事前に存在していた小気球の表面積が低いことと関連していました.
結論:
- イオン誘発核化は,UTLSにおける新しいエアロゾール粒子の地球規模で重要な源である.
- これらの新しく形成された粒子は,特定の大気条件下で測定可能な大きさに成長することができます.
- このプロセスは,雲のマイクロ物理学と地球の放射バランスに潜在的な影響を及ぼします.
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