Topographic evolution and morphology of surfaces evolving in response to coupled fluvial and hillslope sediment transport
Topographic evolution and morphology of surfaces evolving in response to coupled fluvial and hillslope sediment transport
复制标题
地形演化和表面形态演化响应河流和山坡沉积物的耦合输送
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
F. Schlunegger
中科院分区：
文献类型：
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作者：
G. Simpson;F. Schlunegger
[1]本文量化了坡面输沙与河道输沙的比例对地表和河道网络形态以及地形演变动力学的影响。这个问题是调查一个简单的确定性模型，结合泥沙和径流的质量平衡，再加上分散和集中输沙过程相结合的法律的发展和调查。我们的分析包括识别一个新的无量纲参数德是一个函数的降雨量，系统大小，岩石类型，水力制度，这是一个衡量河流和山坡泥沙输运的相对重要性。我们表明，De对表面形态有重要影响（例如，总暴露表面积和反映表面粗糙度和起伏的界面宽度），通道网络形式（例如，河道弯曲度）、河道间距和地表演化的时间尺度。相对于初始地形粗糙度的大小，表面和通道网络形态也受到整体表面坡度的强烈影响。地形演变发生在不同的阶段的救济增长和衰退，之间的过渡是由饱和现象控制的空间相关性的增长。得到了模拟地形在时间和空间上的标度行为，并证明其与De无关。粗糙度指数被发现是独立的De，但依赖于初始粗糙度的大小。界面宽度的增长和衰减作为时间的对数。
[1] This paper quantifies how the ratio of sediment transport on hillslopes to sediment transport in channels influences surface and channel network morphologies and the dynamics of topographic evolution. This problem is investigated by development and investigation of a simple deterministic model incorporating mass balance of sediment and runoff coupled with a law combining dispersive and concentrative sediment transport processes. Our analysis includes the identification of a new nondimensional parameter De that is a function of rainfall, system size, rock type, and hydraulic regime and that is a measure of the relative importance of fluvial and hillslope sediment transport. We show that De has an important influence on the surface morphology (e.g., total exposed surface area and interface width which reflects surface roughness and relief), channel network form (e.g., channel sinuosity), channel spacing, and timescale of surface evolution. Surface and channel network morphologies are also strongly influenced by the overall surface slope relative to the magnitude of initial topographic roughness. Topographic evolution occurs in distinct phases of relief growth and decay, the transition between which is controlled by a saturation phenomenon related to the growth of spatial correlations. The scaling behavior of simulated topography with respect to both time and space is obtained and is shown to be independent of De. Roughness exponents are found to be independent of De but dependent on the magnitude of initial roughness. Interface width is shown to grow and decay as a logarithm of time.