| DOI: | 10.1002/grl.50323
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| 论文题名: | Impulse framework for unsteady flows reveals superdiffusive bed load transport |
| 作者: | Phillips C.B.; Martin R.L.; Jerolmack D.J.
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| 刊名: | Geophysical Research Letters
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| ISSN: | 0094-9187
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| EISSN: | 1944-8918
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| 出版年: | 2013
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| 卷: | 40, 期:7 | | 起始页码: | 1328
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| 结束页码: | 1333
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| 语种: | 英语
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| 英文关键词: | anomalous diffusion
; bed load transport
; hydrograph unsteadiness
; sediment tracer particles
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| Scopus关键词: | Anomalous diffusion
; Bed-load transport
; Hydrographs
; Power law relation
; Quasi-steady flow
; Tracer dispersion
; Tracer particle
; Transport distances
; Dispersions
; Random processes
; Sedimentology
; Sediment transport
; asymmetry
; bedload
; flooding
; flow modeling
; grain size
; random walk method
; sediment transport
; shear flow
; tracer
; unsteady flow
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| 英文摘要: | Sediment transport is an intrinsically stochastic process, and measurement of bed load in the environment is further complicated by the unsteady nature of river flooding. Here we present a methodology for analyzing sediment tracer data with unsteady forcing. We define a dimensionless impulse by integrating the cumulative excess shear velocity for the duration of measurement, normalized by grain size. We analyze the dispersion of a plume of cobble tracers in a very flashy stream over two years. The mean and variance of transport distance collapse onto well-defined linear and power-law relations, respectively, when plotted against cumulative dimensionless impulse. Data suggest that the asymptotic limit of bed load tracer dispersion is superdiffusive, in line with a broad class of geophysical flows exhibiting strong directional asymmetry (advection), thin-tailed step lengths and heavy-tailed waiting times. The impulse framework justifies the use of quasi-steady flow approximations for long-term river evolution modeling. Key Points Variability in hydrographs can be quantified using the dimensionless impulse. Sediment tracers display thin-tailed steps and heavy tailed waiting times. Sediment transport should be modeled as an asymmetric random walk. ©2013. American Geophysical Union. All Rights Reserved. |
| URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876909538&doi=10.1002%2fgrl.50323&partnerID=40&md5=069d53a21030f9393b218c225d74bae4
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/6451
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| Appears in Collections: | 气候减缓与适应
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作者单位: | Department of Earth and Environmental Science, University of Pennsylvania, Philadephia, PA 19104, United States
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| Recommended Citation: | |
Phillips C.B.,Martin R.L.,Jerolmack D.J.. Impulse framework for unsteady flows reveals superdiffusive bed load transport[J]. Geophysical Research Letters,2013-01-01,40(7).
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