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TitleClimate sensitivity of high arctic permafrost terrain demonstrated by widespread ice-wedge thermokarst on Banks Island
AuthorFraser, R HORCID logo; Kokelj, S V; Lantz, T C; McFarlane-Winchester, M; Olthof, I; Lacelle, D
SourceRemote sensing of dynamic permafrost regions; by Jones, B M (ed.); Bartsch, A (ed.); Grosse, G (ed.); Remote Sensing vol. 10, issue 6, 954, 2018 p. 1-24, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20180119
PublisherMDPI AG
Mediaon-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNorthwest Territories
NTS88B; 88C; 88D; 88F; 97G; 97H; 98A; 98B; 98C; 98D; 98E; 98F
AreaBanks Island; Canadian Arctic Archipelago
Lat/Long WENS-126.0000 -115.0000 74.7500 71.0000
Subjectssurficial geology/geomorphology; environmental geology; Nature and Environment; permafrost; ground ice; periglacial features; ice wedges; ice-wedge polygons; thermokarst; solifluction; slumps; climate, arctic; remote sensing; satellite imagery; photogrammetric techniques; airphoto interpretation; reflectance; topography; subsidence; glacial deposits; moraines; tills; soils; ArcticDEM; Amundsen Till; Climate change; monitoring; moraine ridges, ice-cored; change detection; Environmental impact
Illustrationssatellite images; aerial photographs; photographs; schematic representations; location maps; time series; plots
ProgramRemote Sensing Science
Released2018 06 15
AbstractIce-wedge networks underlie polygonal terrain and comprise the most widespread form of massive ground ice in continuous permafrost. Here, we show that climate-driven thaw of hilltop ice-wedge networks is rapidly transforming uplands across Banks Island in the Canadian Arctic Archipelago. Change detection using high-resolution WorldView images and historical air photos, coupled with 32-year Landsat reflectance trends, indicate broad-scale increases in ponding from ice-wedge thaw on hilltops, which has significantly affected at least 1500 km2 of Banks Island and over 3.5% of the total upland area. Trajectories of change associated with this upland ice-wedge thermokarst include increased micro-relief, development of high-centred polygons, and, in areas of poor drainage, ponding and potential initiation of thaw lakes. Millennia of cooling climate have favoured ice-wedge growth, and an absence of ecosystem disturbance combined with surface denudation by solifluction has produced high Arctic uplands and slopes underlain by ice-wedge networks truncated at the permafrost table. The thin veneer of thermally-conductive mineral soils strongly links Arctic upland active-layer responses to summer warming. For these reasons, widespread and intense ice-wedge thermokarst on Arctic hilltops and slopes contrast more muted responses to warming reported in low and subarctic environments. Increasing field evidence of thermokarst highlights the inherent climate sensitivity of the Arctic permafrost terrain and the need for integrated approaches to monitor change and investigate the cascade of environmental consequences.
Summary(Plain Language Summary, not published)
Wedge ice is the most widespread ground ice type in Arctic permafrost. Tundra polygons are the surface expression of underlying ice-wedge networks, which can develop over thousands of years due to thermal contraction cracking of the ground and infilling by snowmelt. Wedge ice is usually encountered at the top of permafrost, so near-surface thawing of this ice from increasing temperatures can cause terrain subsidence and the formation of small melt ponds. Local scale studies (10-100 km2) have shown that recent Arctic warming has been associated with degradation of ice-wedges leading to trough subsidence and ponding of water. In this analysis we used a combination of the 1985-2017 Landsat satellite image archive, high resolution optical satellite imagery, air photos, detailed digital elevation models, and field measurements to show that ice-wedge degradation (or thermokarst) in upland terrain has been extensive over Banks Island in the Canadian Arctic Archipelago during a period of warming since 1998.

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