气候变化领域集成服务门户(CCPortal): Subglacial drainage patterns of Devon Island, Canada: Detailed comparison of rivers and subglacial meltwater channels

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DOI	10.5194/tc-12-1461-2018
	Subglacial drainage patterns of Devon Island, Canada: Detailed comparison of rivers and subglacial meltwater channels
	Grau Galofre A.; Mark Jellinek A.; Osinski G.R.; Zanetti M.; Kukko A.
发表日期	2018
ISSN	19940416
卷号	12 期号:4
英文摘要	Subglacial meltwater channels (N-channels) are attributed to erosion by meltwater in subglacial conduits. They exert a major control on meltwater accumulation at the base of ice sheets, serving as drainage pathways and modifying ice flow rates. The study of exposed relict subglacial channels offers a unique opportunity to characterize the geomorphologic fingerprint of subglacial erosion as well as study the structure and characteristics of ice sheet drainage systems. In this study we present detailed field and remote sensing observations of exposed subglacial meltwater channels in excellent preservation state on Devon Island (Canadian Arctic Archipelago). We characterize channel cross section, longitudinal profiles, and network morphologies and establish the spatial extent and distinctive characteristics of subglacial drainage systems. We use field-based GPS measurements of subglacial channel longitudinal profiles, along with stereo imagery-derived digital surface models (DSMs), and novel kinematic portable lidar data to establish a detailed characterization of subglacial channels in our field study area, including their distinction from rivers and other meltwater drainage systems. Subglacial channels typically cluster in groups of ĝ1/4 10 channels and are oriented perpendicular to active or former ice margins. Although their overall direction generally follows topographic gradients, channels can be oblique to topographic gradients and have undulating longitudinal profiles. We also observe that the width of first-order tributaries is 1 to 2 orders of magnitude larger than in Devon Island river systems and approximately constant. Furthermore, our findings are consistent with theoretical expectations drawn from analyses of flow driven by gradients in effective water pressure related to variations in ice thickness. Our field and remote sensing observations represent the first high-resolution study of the subglacial geomorphology of the high Arctic, and provide quantitative and qualitative descriptions of subglacial channels that revisit well-established field identification guidelines. Distinguishing subglacial channels in topographic data is critical for understanding the emergence, geometry, and extent of channelized meltwater systems and their role in ice sheet drainage. The final aim of this study is to facilitate the identification of subglacial channel networks throughout the globe by using remote sensing techniques, which will improve the detection of these systems and help to build understanding of the underlying mechanics of subglacial channelized drainage. © Author(s) 2018.
学科领域	comparative study; drainage basin; geomorphology; glacial erosion; GPS; ice flow; ice sheet; ice thickness; meltwater; remote sensing; river channel; river system; subglacial environment; tributary; Canada; Canadian Arctic; Devon Island; Nunavut; Queen Elizabeth Islands
语种	英语
scopus关键词	comparative study; drainage basin; geomorphology; glacial erosion; GPS; ice flow; ice sheet; ice thickness; meltwater; remote sensing; river channel; river system; subglacial environment; tributary; Canada; Canadian Arctic; Devon Island; Nunavut; Queen Elizabeth Islands
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/119170
作者单位	Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada; Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada; Department of Earth Sciences and Centre for Planetary Science and Exploration, University of Western Ontario, London, ON, Canada; Center of Excellence in Laser Scanning Research, Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute Geodeetinrinne 2, Masala, Finland
推荐引用方式 GB/T 7714	Grau Galofre A.,Mark Jellinek A.,Osinski G.R.,et al. Subglacial drainage patterns of Devon Island, Canada: Detailed comparison of rivers and subglacial meltwater channels[J],2018,12(4).
APA	Grau Galofre A.,Mark Jellinek A.,Osinski G.R.,Zanetti M.,&Kukko A..(2018).Subglacial drainage patterns of Devon Island, Canada: Detailed comparison of rivers and subglacial meltwater channels.Cryosphere,12(4).
MLA	Grau Galofre A.,et al."Subglacial drainage patterns of Devon Island, Canada: Detailed comparison of rivers and subglacial meltwater channels".Cryosphere 12.4(2018).