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DOI | 10.1029/2021GL094572 |
Mechanisms of dune growth and decay in rivers | |
Ryan Bradley; Jeremy G. Venditti | |
2021-09-29 | |
发表期刊 | Geophysical Research Letters |
出版年 | 2021 |
英文摘要 | The mechanisms responsible for dune growth and decay remain a major unknown in river dynamics. Two theories have been supported by experiments and numerical models. A hydrodynamic explanation suggests growth and decay occur due to phase lags between bed topography and sediment flux. Alternatively, kinematic processes have been invoked to explain growth by merger and decay by superimposed bedforms cannibalizing larger dunes. Demonstration of either mechanism in natural rivers has been lacking due to a paucity of high-resolution topography. Here, we provide the first observations of rapid dune growth by kinematic processes during a rising hydrograph limb, followed by gradual adjustments likely through hydrodynamic processes at high flow. As flow wanes, smaller dunes develop and cannibalize larger features, eventually creating a flattened bed near base flow. Kinematic processes occur at a common threshold shear stress. Superimposed dunes formed during falling limbs of hydrographs are signatures of dune decay. |
领域 | 气候变化 |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/338876 |
专题 | 气候变化 |
推荐引用方式 GB/T 7714 | Ryan Bradley,Jeremy G. Venditti. Mechanisms of dune growth and decay in rivers[J]. Geophysical Research Letters,2021. |
APA | Ryan Bradley,&Jeremy G. Venditti.(2021).Mechanisms of dune growth and decay in rivers.Geophysical Research Letters. |
MLA | Ryan Bradley,et al."Mechanisms of dune growth and decay in rivers".Geophysical Research Letters (2021). |
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