DOI: 10.1002/2017JD026510
论文题名: Highly variable aerodynamic roughness length (z0) for a hummocky debris-covered glacier
作者: Miles E.S. ; Steiner J.F. ; Brun F.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2017
卷: 122, 期: 16 起始页码: 8447
结束页码: 8466
语种: 英语
英文关键词: aerodynamic roughness
; debris-covered glaciers
; microtopography
; turbulent fluxes
英文摘要: The aerodynamic roughness length (z0) is an essential parameter in surface energy balance studies, but few literature values exist for debris-covered glaciers. We use microtopographic and aerodynamic methods to assess the spatial variability of z0 for Lirung Glacier, Nepal. We apply structure from motion to produce digital elevation models for three nested domains: five 1 m2 plots, a 21,300 m2 surface depression, and the lower 550,000 m2 of the debris-mantled tongue. Wind and temperature sensor towers were installed in the vicinity of the plots within the surface depression in October 2014. We calculate z0 according to a variety of transect-based microtopographic parameterizations for each plot, then develop a grid version of the algorithms by aggregating data from all transects. This grid approach is applied to the surface depression digital elevation model to characterize z0 spatial variability. The algorithms reproduce the same variability among transects and plots, but z0 estimates vary by an order of magnitude between algorithms. Across the study depression, results from different algorithms are strongly correlated. Using Monin-Obukov similarity theory, we derive z0 values from the meteorological data. Using different stability criteria, we derive median values of z0 between 0.03 m and 0.05 m, but with considerable uncertainty due to the glacier's complex topography. Considering estimates from these algorithms, results suggest that z0 varies across Lirung Glacier between ∼0.005 m (gravels) to ∼0.5 m (boulders). Future efforts should assess the importance of such variable z0 values in a distributed energy balance model. ©2017. 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/62597
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: Scott Polar Research Institute, University of Cambridge, Cambridge, United Kingdom; School of Geography, University of Leeds, Leeds, United Kingdom; Department of Physical Geography, Universiteit Utrecht, Utrecht, Netherlands; University Grenoble Alpes, CNRS, IRD, LTHE, Grenoble, France
Recommended Citation:
Miles E.S.,Steiner J.F.,Brun F.. Highly variable aerodynamic roughness length (z0) for a hummocky debris-covered glacier[J]. Journal of Geophysical Research: Atmospheres,2017-01-01,122(16)