DOI: 10.1002/2017JF004464
Scopus记录号: 2-s2.0-85042405407
论文题名: Island Formation Resulting From Radially Symmetric Flow Expansion
作者: Shaw J.B. ; Miller K. ; McElroy B.
刊名: Journal of Geophysical Research: Earth Surface
ISSN: 21699003
出版年: 2018
卷: 123, 期: 2 起始页码: 363
结束页码: 383
语种: 英语
英文关键词: coast
; delta
; flow expansion
; island
; jet
; mouth bar
Scopus关键词: bar
; channelization
; coastal zone
; deltaic deposit
; expansion
; island
; jet
; radial flow
英文摘要: Island formation and distributary channel branching are important processes in prograding river deltas. We develop and test a new theory predicting the distance to islands and channel bifurcations based on fluid mass conservation and radially symmetric transport conditions. We analyze channelization and island formation using nine new and five existing delta experiments as well as four field deltas. The new experiments were designed to produce islands from initial deposition of a mouth bar. Before island formation, each bar evolved into a radially symmetric deposit with unchannelized flow over its top previously described as a topographic flow expansion. This morphology was stable to topographic perturbations, and its distal limit prograded basinward while maintaining a characteristic flow depth. Island formation and channel branching occurred on top of this deposit. We hypothesize that this distance (Ψ) is set by the location where boundary shear stress applied by expanding, radially averaged flow falls below the threshold of sediment motion. The model predicts that the distance to the first island scales with water discharge, scales inversely with flow depth, and scales with the inverse square root of median grain diameter. From experiment to field scales, distances to island locations are predicted within a factor of two. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114503
Appears in Collections: 气候减缓与适应
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作者单位: Department of Geosciences, University of Arkansas, Fayetteville, AR, United States; Department of Geology and Geophysics, University of Wyoming, Laramie, WY, United States; Jackson School of Geosciences, University of Texas, Austin, TX, United States
Recommended Citation:
Shaw J.B.,Miller K.,McElroy B.. Island Formation Resulting From Radially Symmetric Flow Expansion[J]. Journal of Geophysical Research: Earth Surface,2018-01-01,123(2)