切断された川の渦巻の気候のサインは,曲がりくねりです
Colin P Stark1, Jonathan R Barbour, Yuichi S Hayakawa
1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA. cstark@ldeo.columbia.edu
まとめ
台風の降雨は,山の景観に独特の河川のパターンを生み出します. 曲がりくねりの尺度である河川の曲がりくねりは,台風が起こる傾向のある亜熱帯地域で最も高く,気候を明らかにします.
科学分野:
- 地球科学 地球科学 地球科学
- ジオモルフォロジー ジオモルフォロジー
- 気候学 気候学
背景:
- 気候は景観の進化に大きく影響を与えますが,気候の要因の直接的な地形学的証拠は,大規模なスケールでは捉え難いままです.
- 山川系は,環境変化の敏感な指標であり,構造的,気候的,岩石学的要因の相互作用を反映しています.
研究 の 目的:
- 山川系における台風による降雨のトポグラフィックシグネチャーを特定し,定量化する.
- 西北太平洋の河川の渦巻性,気候,岩盤の性質の関係を調査する.
主な方法:
- 空間的に平均された河川の状性を計算するために,デジタル標高データを分析する.
- 異なる気候圏 (亜熱帯,赤道熱帯,中緯度) にわたる河川の状性のパターンの統計的比較.
- 斜面性の相関は,気候の変数 (台風の頻度) と地質的要因 (岩の弱さ) と関係している.
主要な成果:
- 川の状性は台風が多発する亜熱帯地域で顕著なピークを示し,極端な降雨現象と相関しています.
- シヌオシティは,赤道熱帯と極端な降雨の頻度が少ない中緯度に向かって減少します.
- 気候を考慮すると,岩盤の弱さは,川の曲性を制御する主要な要因として浮上する.
結論:
- 台風による降雨は,山岳川を切り裂く状に,定量的に測りうる地形的な痕跡を残します.
- 岩盤の運河壁の弱さと降雨による侵食の組み合わせによる影響は,河川の曲がりくねりと曲がりくねりの発展を調節する.
- この研究は,河川の地形から過去の気候条件を推論するための新しい方法を提供します.
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