文章基本信息

标题：Roughness of a subglacial conduit under Hansbreen, Svalbard
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作者：KENNETH D. MANKOFF ; JASON D. GULLEY ; SLAWEK M. TULACZYK 等
期刊名称：Journal of Glaciology
印刷版ISSN：0022-1430
电子版ISSN：1727-5652
出版年度：2017
卷号：63
期号：239
页码：423-435
DOI：10.1017/jog.2016.134
出版社：Cambridge University Press
摘要：ABSTRACT Hydraulic roughness exerts an important but poorly understood control on water pressure in subglacial conduits. Where relative roughness values are 5%. Here we report the first quantitative assessment of roughness heights and hydraulic diameters in a subglacial conduit. We measured roughness heights in a 125 m long section of a subglacial conduit using structure-from-motion to produce a digital surface model, and hand-measurements of the b -axis of rocks. We found roughness heights from 0.07 to 0.22 m and cross-sectional areas of 1–2 m 2 , resulting in relative roughness of 3–12% and >5% for most locations. A simple geometric model of varying conduit diameter shows that when the conduit is small relative roughness is >30% and has large variability. Our results suggest that parameterizations of conduit hydraulic roughness in subglacial hydrological models will remain challenging until hydraulic diameters exceed roughness heights by a factor of 20, or the conduit radius is >1 m for the roughness elements observed here.
关键词：glacier hydrology;roughness;subglacial conduits