气候变化领域集成服务门户(CCPortal): Subglacial roughness of the Greenland Ice Sheet: Relationship with contemporary ice velocity and geology

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DOI	10.5194/tc-13-3093-2019
	Subglacial roughness of the Greenland Ice Sheet: Relationship with contemporary ice velocity and geology
	Cooper M.A.; Jordan T.M.; Schroeder D.M.; Siegert M.J.; Williams C.N.; Bamber J.L.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	3093
结束页码	3115
卷号	13 期号:11
英文摘要	The subglacial environment of the Greenland Ice Sheet (GrIS) is poorly constrained both in its bulk properties, for example geology, the presence of sediment, and the presence of water, and interfacial conditions, such as roughness and bed rheology. There is, therefore, limited understanding of how spatially heterogeneous subglacial properties relate to ice-sheet motion. Here, via analysis of 2 decades of radio-echo sounding data, we present a new systematic analysis of subglacial roughness beneath the GrIS. We use two independent methods to quantify subglacial roughness: first, the variability in along-track topography - enabling an assessment of roughness anisotropy from pairs of orthogonal transects aligned perpendicular and parallel to ice flow and, second, from bed-echo scattering - enabling assessment of fine-scale bed characteristics. We establish the spatial distribution of subglacial roughness and quantify its relationship with ice flow speed and direction. Overall, the beds of fast-flowing regions are observed to be rougher than the slow-flowing interior. Topographic roughness exhibits an exponential scaling relationship with ice surface velocity parallel, but not perpendicular, to flow direction in fast-flowing regions, and the degree of anisotropy is correlated with ice surface speed. In many slow-flowing regions both roughness methods indicate spatially coherent regions of smooth beds, which, through combination with analyses of underlying geology, we conclude is likely due to the presence of a hard flat bed. Consequently, the study provides scope for a spatially variable hard- or soft-bed boundary constraint for ice-sheet models. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
学科领域	flow velocity; ice flow; ice sheet; sound scattering; subglacial deposit; subglacial environment; surface roughness; topography; Arctic; Greenland; Greenland Ice Sheet
语种	英语
scopus关键词	flow velocity; ice flow; ice sheet; sound scattering; subglacial deposit; subglacial environment; surface roughness; topography; Arctic; Greenland; Greenland Ice Sheet
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118804
作者单位	School of Geographical Sciences, University of Bristol, Bristol, United Kingdom; Department of Geophysics, Stanford University, Stanford, CA, United States; Department of Electrical Engineering, Stanford University, Stanford, CA, United States; Grantham Institute, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Department of Environment and Geography, University of York, York, United Kingdom; British Geological Survey, Nottingham, United Kingdom
推荐引用方式 GB/T 7714	Cooper M.A.,Jordan T.M.,Schroeder D.M.,et al. Subglacial roughness of the Greenland Ice Sheet: Relationship with contemporary ice velocity and geology[J],2019,13(11).
APA	Cooper M.A.,Jordan T.M.,Schroeder D.M.,Siegert M.J.,Williams C.N.,&Bamber J.L..(2019).Subglacial roughness of the Greenland Ice Sheet: Relationship with contemporary ice velocity and geology.The Cryosphere,13(11).
MLA	Cooper M.A.,et al."Subglacial roughness of the Greenland Ice Sheet: Relationship with contemporary ice velocity and geology".The Cryosphere 13.11(2019).