文章基本信息

标题：New insights into the subglacial and periglacial hydrology of Vatnajökull, Iceland, from a distributed physical model
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作者：Gwenn E. Flowers ; Helgi Björnsson ; Finnur Pálsson 等
期刊名称：Journal of Glaciology
印刷版ISSN：0022-1430
电子版ISSN：1727-5652
出版年度：2003
卷号：49
期号：165
页码：257-270
DOI：10.3189/172756503781830827
出版社：Cambridge University Press
摘要：We apply a time-dependent distributed glaciohydraulic model to Vatnajökull ice cap, Iceland, aiming to determine the large-scale subglacial drainage structure, the importance of basally derived meltwater, the influence of a permeable glacier bed and Vatnajökull’s discharge contribution to major rivers in Iceland. The model comprises two coupled layers that represent the subglacial horizon perched on a subsurface aquifer in the western sector and bedrock in the eastern sector. To initialize and drive the simulations, we use digital elevation models of the ice surface and bed, the 1999/2000 measured mass balance and an estimate of subglacial geothermal heat fluxes. The modelled subglacial flow field differs substantially from that derived by hydraulic-potential calculations, and the corresponding distribution of basal effective pressure shows a strong correlation between low effective pressure and surge-prone areas in northeastern and southern sectors of Vatnajökull. Simulations suggest that geothermally derived basal melt may account for up to ∼5% of the annual glacial discharge, and buried aquifers may evacuate up to ∼30% of subglacialwater.Time-dependent tests yield estimates of the glacial discharge component in various outlet rivers and suggest a possible seasonal migration of subglacial hydraulic divides. This study of present-day Vatnajökull hydrology forms the starting point for investigations of its future evolution.