DOI: 10.1029/2017JF004416
Scopus记录号: 2-s2.0-85050773115
论文题名: Distinct Thresholds for the Initiation and Cessation of Aeolian Saltation From Field Measurements
作者: Martin R.L. ; Kok J.F.
刊名: Journal of Geophysical Research: Earth Surface
ISSN: 21699003
出版年: 2018
卷: 123, 期: 7 起始页码: 1546
结束页码: 1565
语种: 英语
英文关键词: boundary layer flows
; eolian processes
; saltation
; sediment transport thresholds
; wind erosion
英文摘要: Wind-blown sand and dust models depend sensitively on the threshold wind stress. However, laboratory and numerical experiments suggest the coexistence of distinct fluid and impact thresholds for the initiation and cessation of aeolian saltation, respectively. Because aeolian transport models typically use only a single threshold, existence of separate higher fluid and lower impact thresholds complicates the prediction of wind-driven transport. Here we extend the statistical Time Frequency Equivalence Method to derive the first field-based estimates of distinct fluid and impact thresholds from high-frequency wind and saltation measurements at three field sites. Our measurements show that when saltation is mostly inactive, its instantaneous occurrence is governed primarily by wind exceedance of the fluid threshold. As saltation activity increases, so too does the relative importance of the impact threshold, until it dominates under near-continuous transport conditions. Although both thresholds are thus important for high-frequency saltation prediction, our results suggest that the time-averaged saltation flux is primarily governed by the impact threshold. ©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/113537
Appears in Collections: 气候减缓与适应
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作者单位: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, United States
Recommended Citation:
Martin R.L.,Kok J.F.. Distinct Thresholds for the Initiation and Cessation of Aeolian Saltation From Field Measurements[J]. Journal of Geophysical Research: Earth Surface,2018-01-01,123(7)