气候变化领域集成服务门户(CCPortal): Supraglacial debris thickness variability: Impact on ablation and relation to terrain properties

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DOI	10.5194/tc-12-3719-2018
	Supraglacial debris thickness variability: Impact on ablation and relation to terrain properties
	Nicholson L.I.; McCarthy M.; Pritchard H.D.; Willis I.
发表日期	2018
ISSN	19940416
卷号	12 期号:12
英文摘要	Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis of the debris thickness frequency distribution decrease with increasing mean debris thickness, and we hypothesize that this is related to the degree of gravitational reworking the debris cover has undergone and is therefore a proxy for the maturity of surface debris covers. In the cases tested here, using a single mean debris thickness value instead of accounting for the observed small-scale debris thickness variability underestimates modelled midsummer sub-debris ablation rates by 11 %-30 %. While no simple relationship is found between measured debris thickness and morphometric terrain parameters, analysis of the GPR data in conjunction with high-resolution terrain models provides some insight into the processes of debris gravitational reworking. Periodic sliding failure of the debris, rather than progressive mass diffusion, appears to be the main process redistributing supraglacial debris. The incidence of sliding is controlled by slope, aspect, upstream catchment area and debris thickness via their impacts on predisposition to slope failure and meltwater availability at the debris-ice interface. Slope stability modelling suggests that the percentage of the debris-covered glacier surface area subject to debris instability can be considerable at glacier scale, indicating that up to 32 % of the debris-covered area is susceptible to developing ablation hotspots associated with patches of thinner debris. © 2018 Author(s).
学科领域	ablation; glacial debris; ground penetrating radar; reworking; sediment thickness; sliding; slope failure; slope stability; surface area; terrain; Himalayas
语种	英语
scopus关键词	ablation; glacial debris; ground penetrating radar; reworking; sediment thickness; sliding; slope failure; slope stability; surface area; terrain; Himalayas
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119023
作者单位	Department of Atmospheric and Cryospheric Sciences, Universität Innsbruck, Innsbruck, Austria; British Antarctic Survey, Natural Environment Research Council, Madingley Road, Cambridge, United Kingdom; Scott Polar Research Institute, University of Cambridge, Cambridge, United Kingdom
推荐引用方式 GB/T 7714	Nicholson L.I.,McCarthy M.,Pritchard H.D.,et al. Supraglacial debris thickness variability: Impact on ablation and relation to terrain properties[J],2018,12(12).
APA	Nicholson L.I.,McCarthy M.,Pritchard H.D.,&Willis I..(2018).Supraglacial debris thickness variability: Impact on ablation and relation to terrain properties.Cryosphere,12(12).
MLA	Nicholson L.I.,et al."Supraglacial debris thickness variability: Impact on ablation and relation to terrain properties".Cryosphere 12.12(2018).