北極圏の大気中のNOxの起源と運命を,窒素酸塩の安定同位素を用いて追跡する
Samuel Morin1, Joël Savarino, Markus M Frey
1CNRS, Institut National des Sciences de l'Univers, France. samuel.morin@ujf-grenoble.fr
まとめ
北極圏の大気中の窒素は,春の雪積みの排出から発生する. ブロム酸化物は局所的に窒素酸化物 (NOx) を酸化し,窒素の予算と大気化学に大きな影響を及ぼします.
科学分野:
- 大気化学 大気化学
- イソトープ地質化学とは
- 北極の環境科学 北極の環境科学
背景:
- 窒素酸化物 (NOx) は,反応性窒素循環と大気中の酸化能力にとって極めて重要です.
- 窒素の堆積は,活性窒素循環の重要な構成要素である.
- NOxと窒素の源と変換を理解することは,大気の研究に不可欠です.
研究 の 目的:
- 北極における大気中の窒素酸化物 (NOx) と窒素酸塩の季節的起源と運命を調査する.
- 源を特定するために,窒素中の窒素と酸素の安定した同位体比を利用する.
- 窒素酸塩の形成における大気中の酸化物質の役割を制限するために.
主な方法:
- 北極圏の大気中の窒素サンプルを採取,分析.
- 窒素と酸素の安定同位体比 (15N/14Nと18O/16O) を窒素酸で測定する.
- 同位体分析を用いて,NOxと窒素の源と変換経路を推論する.
主要な成果:
- 春には,雪から発生する反応性窒素の光化学的排出が大気 NOx に大きく寄与する.
- NOxのブロミン酸化物による局所的酸化は,北極の春の窒素形成の主要な経路として浮上しています.
- 窒素酸塩の同位体組成は,大気中の酸化物質の相対的な重要性に強い制約を与える.
結論:
- この研究は,北極圏の大気中,特に春の間,窒素形成の主要な経路を明らかにしています.
- NOxのブロム酸化物媒介による酸化は,北極の窒素予算に影響を与える重要なプロセスとして特定されています.
- 窒素酸塩の同位体分析は,過去の大気条件と酸化状態を再構築するための強力なツールです.
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