青藏高原冲积河群空间分布及维持条件

Spatial distribution and sustaining conditions of meandering and braided river clusters on the Qinghai-Tibet Plateau

  • 摘要: 本研究旨在全面揭示青藏高原冲积河流地貌的整体特征与形成机制。基于2010—2025年野外考察与GIS空间分析,提出“冲积河群”概念,用以刻画高原集中发育的同类河型干支流系统。结果表明:高原以弯曲与辫状河群为主导类型,其中弯曲河群集中分布于黄河与怒江源区,辫状河群在五大江河源区广泛发育。冲积河群格局受下垫面与水沙条件协同控制,弯曲河群多见于植被茂密、坡度平缓、水多沙少流域;辫状河群则形成于坡度大、植被稀疏、水少沙多区域。进一步发现,河谷坡度与河流弯曲度呈显著正相关,揭示冲积河群通过形态自调整实现能量优化的内在规律。本研究为理解青藏高原河流水系结构、演变及其对气候变化的响应提供了新框架。

     

    Abstract: This study aims to completely reveal the overall characteristics and formation mechanisms of fluvial landscapes on the Qinghai-Tibet Plateau (QTP). Based on field investigations (2010—2025) and GIS-based spatial analysis, we propose the concept of "alluvial river clusters" to describe the concentrated development of tributary and mainstem systems sharing similar channel patterns on the QTP . The results indicate that meandering and braided river clusters dominate the alluvial river systems: meandering clusters are predominantly found in the source regions of the Yellow River and Nu River, while braided clusters are extensively developed across the source areas of the five major rivers. The spatial distribution of these river clusters is jointly controlled by underlying surface characteristics and water-sediment conditions. Meandering clusters typically occur in basins with dense vegetation, gentle slopes, and higher water but lower sediment supply, whereas braided clusters form in areas with steeper valley gradients, sparse vegetation, and lower water but higher sediment supply. Furthermore, a significant positive correlation between valley slope and channel sinuosity was identified, revealing an intrinsic self-adjustment mechanism through which river clusters optimize energy dissipation. This study contributes a novel framework for understanding the structure, evolution, and climatic responses of alpine river network systems on the QTP.

     

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