气候变化领域集成服务门户(CCPortal): Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard

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DOI	10.5194/tc-8-1951-2014
	Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard
	Schäfer M.; Gillet-Chaulet F.; Gladstone R.; Pettersson R.; Pohjola V.A.; Strozzi T.; Zwinger T.
发表日期	2014
ISSN	19940416
卷号	8 期号:5
英文摘要	Understanding the response of fast flowing ice streams or outlet glaciers to changing climate is crucial in order to make reliable projections of sea level change over the coming decades. Motion of fast outlet glaciers occurs largely through basal motion governed by physical processes at the glacier bed, which are not yet fully understood. Various subglacial mechanisms have been suggested for fast flow but common to most of the suggested processes is the requirement of presence of liquid water, and thus temperate conditions. We use a combination of modelling, field, and remote observations in order to study links between different heat sources, the thermal regime and basal sliding in fast flowing areas on Vestfonna ice cap. A special emphasis lies on Franklinbreen, a fast flowing outlet glacier which has been observed to accelerate recently. We use the ice flow model Elmer/Ice including a Weertman type sliding law and a Robin inverse method to infer basal friction parameters from observed surface velocities. Firn heating, i.e. latent heat release through percolation of melt water, is included in our model; its parameterisation is calibrated with the temperature record of a deep borehole. We found that strain heating is negligible, whereas friction heating is identified as one possible trigger for the onset of fast flow. Firn heating is a significant heat source in the central thick and slow flowing area of the ice cap and the essential driver behind the ongoing fast flow in all outlets. Our findings suggest a possible scenario of the onset and maintenance of fast flow on the Vestfonna ice cap based on thermal processes and emphasise the role of latent heat released through refreezing of percolating melt water for fast flow. However, these processes cannot yet be captured in a temporally evolving sliding law. In order to simulate correctly fast flowing outlet glaciers, ice flow models not only need to account fully for all heat sources, but also need to incorporate a sliding law that is not solely based on the basal temperature, but also on hydrology and/or sediment physics. © 2014 Author(s).
学科领域	climate effect; friction; heat source; ice cap; ice flow; ice stream; inverse analysis; sea level change; subglacial environment; Arctic; Nordaustlandet; Svalbard; Svalbard; Svalbard and Jan Mayen; Vestfonna
语种	英语
scopus关键词	climate effect; friction; heat source; ice cap; ice flow; ice stream; inverse analysis; sea level change; subglacial environment; Arctic; Nordaustlandet; Svalbard; Svalbard; Svalbard and Jan Mayen; Vestfonna
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/120037
作者单位	Arctic Centre, University of Lapland, Rovaniemi, Finland; Finnish Meteorological Institut, Helsinki, Finland; Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS-Univ. Grenoble Alpes, Grenoble, 38041, France; Department of Earth Sciences, Air, Water and Landscape Science, Uppsala University, Uppsala, Sweden; Gamma Remote Sensing and Consulting AG, Gümligen, Switzerland; CSC-IT Center for Science Ltd., Espoo, Finland
推荐引用方式 GB/T 7714	Schäfer M.,Gillet-Chaulet F.,Gladstone R.,et al. Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard[J],2014,8(5).
APA	Schäfer M..,Gillet-Chaulet F..,Gladstone R..,Pettersson R..,Pohjola V.A..,...&Zwinger T..(2014).Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard.Cryosphere,8(5).
MLA	Schäfer M.,et al."Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard".Cryosphere 8.5(2014).