DOI: 10.1002/jgrd.50687
论文题名: Timescale dependence of aeolian sand flux observations under atmospheric turbulence
作者: Martin R.L. ; Barchyn T.E. ; Hugenholtz C.H. ; Jerolmack D.J.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 16 起始页码: 9078
结束页码: 9092
语种: 英语
Scopus关键词: Atmospheric turbulence
; Reynolds number
; Sand
; Sediment transport
; Shear stress
; Fitting parameters
; High frequency HF
; Reynolds stress
; Saltation fluxes
; Stress fluctuations
; Time-scale dependence
; Turbulent wind
; Wind velocities
; Flow visualization
; eolian deposit
; frequency analysis
; hysteresis
; observational method
; Reynolds number
; saltation
; sediment transport
; threshold
; timescale
; turbulence
英文摘要: The transport of sand in saltation is driven by the persistently unsteady stresses exerted by turbulent winds. Based on coupled high-frequency observations of wind velocity and sand flux on a desert dune during intermittent saltation, we show here how observations of saltation by natural winds depend significantly on the timescale and method used for determining shear stress and sand flux. The correlation between sand flux and excess shear stress (stress above a threshold value) systematically improves for longer averaging timescale, T, and is better for stress determined by the law-of-the-wall versus the Reynolds stress method. Fitting parameters for the stress-flux relationship do not converge with increasing T, which may be explained by the nonstationary nature of wind velocity statistics. We show how it may be possible, based on the scale-dependent statistics of stress fluctuations, to rescale saltation flux predictions for wind observations made at different timescales. However, our observations indicate hysteresis and time lags in thresholds for initiation and cessation of saltation, which complicate threshold-based approaches to predicting sediment transport at different timescales. © 2013. Her Majesty the Queen in Right of Canada. American Geophysical Union. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63417
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104, United States; Department of Geography, University of Lethbridge, Lethbridge, AB, Canada
Recommended Citation:
Martin R.L.,Barchyn T.E.,Hugenholtz C.H.,et al. Timescale dependence of aeolian sand flux observations under atmospheric turbulence[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(16)