1960年以来,北部の生態系による二酸化炭素の季節的交換が強化された
H D Graven1, R F Keeling, S C Piper
1Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA. hgraven@ucsd.edu
まとめ
北半球における大気中の二酸化炭素 (CO2) の季節的変動は,特に北極地域では,著しく増加しています. これは,世界の炭素循環に影響を与える北部の森林における主要な生態学的シフトを示唆しています.
科学分野:
- * 地球と環境科学
- *大気化学について
- * エコロジー * エコロジー
背景:
- *北半球における大気中の二酸化炭素 (CO2) の季節的変動は,1950年代以降,拡大している.
- * 限られた観測データは,長期的な変化とその要因の包括的な理解を妨げています.
- * 過去の研究では,CO2の季節性が増えていることが示されていますが,地域的なパターンと大きさは不明です.
研究 の 目的:
- *北太平洋と北極海における大気中のCO2の長期変化や季節的変動を評価する.
- * 観測されたCO2パターンを駆動する根本的なメカニズムを調査する.
- * 最近の航空機観測を1958年から1961年の過去のデータと比較する.
主な方法:
- * 最近の航空機による大気中のCO2観測の分析.
- *1958年から1961年の CO2 データの比較.
- *異なる緯度帯 (10°-45°N,45°-90°N) の3~6kmの高さの季節的なCO2振幅の測定.
主要な成果:
- * 大気中のCO2の季節的な振幅の50%の増加は,45°-90°Nの3-6 kmの高さで観察されました.
- * 季節性CO2振幅の25%未満の増加が10°-45°Nで確認されました.
- * 北部の熱帯外陸の生態系,特に北極の森林による季節性CO2交換の30~60%の増加が示唆されている.
結論:
- * 観測されたCO2の増加は,北部の森林における重要な生態学的変化を示唆しています.
- *この結果は,現在の陸上生態系モデルのシミュレーションを上回る,地球規模の炭素サイクルにおける実質的な変化を示しています.
- * 強化されたCO2の季節性により,陸上の生態系と大気間のよりダイナミックな相互作用が示唆される.
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