川や小川の地球規模
George H Allen1, Tamlin M Pavelsky2
1Department of Geological Sciences, University of North Carolina, Chapel Hill, NC, USA. georgehenryallen@gmail.com.
まとめ
地球上の川と小川の表面積は,前述の推定より44%大きく,陸地と大気間のガス交換に大きな影響を与えている. この発見は 川が現在認識されているよりも 世界的な炭素予算に 大きな役割を果たしていることを示しています
科学分野:
- 地理科学
- 環境科学
- 水学
背景:
- 川や小川は 地球の表面と大気間の生地化学的交換のための重要な場所です
- 地球上の河川網の表面積の正確な推定は,二酸化炭素のような陸と大気間の微量ガス流の理解に不可欠です.
- 河川と小川の表面積の過去の空間的推定は,十分に制限されていません.
研究 の 目的:
- 世界的な川と小川のネットワークの総面積を定量化します.
- 川や小川が地球生物化学の循環に与える影響を再評価する.
- 世界的な炭素予算の見積もりを改善する
主な方法:
- 川の平面形水形学のグローバルデータベースを利用した.
- 平均年間排出面積を統計的アプローチで推定した.
- 新しい推定値と以前の空間データを比較した.
主要な成果:
- 世界の川と小川の表面積は773,000 ± 79,000平方キロメートル (0.58 ± 0.06% 地球の氷河のない陸地表面) と推定されています.
- これは,以前の空間的見積もりと比較して44 ± 15%の増加を表しています.
- この発見は,陸と大気間の流れを制御する上で 川や小川の役割が 大きくなる可能性があることを示しています
結論:
- 世界の川や小川の総面積は 大きく過小評価されています
- 川や小川は地球上の生地化学的サイクルに 影響を与える可能性が高く,現在では地球規模の炭素予算に 反映されているほどではありません.
- 気候と炭素サイクルを正確にモデル化するには 改訂された推定値が不可欠です
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