大規模なツンドラメタン噴出は,凍結が始まると発生した
Mikhail Mastepanov1, Charlotte Sigsgaard, Edward J Dlugokencky
1GeoBiosphere Science Centre, Physical Geography and Ecosystems Analysis, Lund University, Sölvegatan 12, 22362, Lund, Sweden.
Nature
|December 5, 2008
まとめ
北極の湿地からのメタン排出量は,土壌の凍結時に大幅に増加し,以前は認識されていなかった現象です. この"凍結爆発"は夏の排出量に匹敵し,高い北緯度の大気中のメタンパターンを説明するのに役立ちます.
科学分野:
- 環境科学 環境科学
- 大気化学 大気化学
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 陸上の湿地は大気中のメタンの主要な源である.
- 地球規模のメタン排出量に対する高緯度湿地の貢献は完全に理解されていません.
- 北極で観測されたメタンのパターン,特に晩秋の増加は,明確な源の属性がない.
研究 の 目的:
- 秋の凍結期間の高北極の湿地からのメタンの排出を調査する.
- 成長シーズンの排出量に対するフリーズイン排出量の重要性を定量化するために.
- 高北緯度の大気メタンモデルの精度を向上させるため.
主な方法:
- メタンのフロースの毎時間測定を秋の終わりと冬の初めまで延長した.
- 高北極の環境で土壌の凍結が始まるときに収集されたデータ.
- 3D大気化学と輸送モデルのシミュレーションを活用しました.
主要な成果:
- メタンの排出量は成長期の後に減少したが,土壌の凍結期には著しく増加した.
- 凍結期間の排出量は,夏季全体の排出量とほぼ同じであることが判明しました.
- これらの排出を組み込んだモデルのシミュレーションは,北緯60度以北の観測された大気中のメタンデータと一致性を改善しました.
結論:
- 凍結期間の永久凍土に関連したメタンの排出は,北極圏のメタンの放出の実質的な,かつ以前に過小評価された構成要素です.
- これらの発見は,高北緯度で観察された晩秋のメタンシールドを説明するのに役立ちます.
- フリーズインバーストの認識は,地球規模のメタンサイクルと気候変動の影響を正確にモデル化するために不可欠です.
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