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TitleIcings in the Lac la Martre area (1984-2015), Northwest Territories, mapped from Landsat imagery
AuthorFish, C S; Morse, P D; Wolfe, S A
SourceGeological Survey of Canada, Open File 8124, 2017, 43 pages,
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf; rtf; shp; xml
ProvinceNorthwest Territories
NTS85E/16; 85F/13; 85F/14; 85F/15; 85K; 85L; 85M; 85N
AreaLac la Martre
Lat/Long WENS-120.3333 -115.7500 63.8333 61.7500
Subjectsenvironmental geology; hydrogeology; cold regions research; ice; transportation; regional planning; computer mapping; satellite imagery; satellites; LANDSAT; permafrost; groundwater; groundwater flow; surface waters; rivers; lakes; hydrologic environment; snow; Bear Province; Interior Platform; icings; geographic information systems (GIS); Normalized Difference Snow Index (NDSI); Maximized Difference Ice Index (MDII); data processing; water masking; ecoregions; band ratios
Illustrationslocation maps; photographs; time series; sketch maps; tables; satellite images; frequency distribution diagrams; flow diagrams; plots
ProgramLand-based Infrastructure, Climate Change Geoscience
Released2017 02 21
AbstractIcings are sheet-like masses of layered ice that form over the winter by freezing of successive flows of water on the ground surface or on top of river or lake ice. Icings can negatively impact the performance of seasonal and all-season roads and are a transportation risk in Arctic regions. Therefore, maps of their occurrence and reoccurrence provide important geoscience information required for development and transportation infrastructure planning. In this study, a set of icing maps was derived using threshold values of band ratios from a time series of Landsat images (1984 - 2015), located within the Bear and Interior Platform Geological Provinces in the Lac la Martre area, NWT (WRS-2 Path 49/Row 16). The icings maps were generated using images acquired in late spring when the region is largely snow-free, but ice bodies remain. A water mask created from summer images was used to differentiate between different types of frozen water bodies (rivers, lakes, icings), so any remaining ice was considered to be icings. Icing reoccurrence maps were generated by overlaying successive icing distribution maps in a Geographic Information System. This Open File contains the digital, georeferenced icing data.
Summary(Plain Language Summary, not published)
Icings are mapped in permafrost terrain in the Lac laMartre area, Northwest Territories. Icings are sheet-like masses of layered ice that form over the winter by freezing of successive flows of water on the surface. Icings are a potential hazard to northern ice roads as they can damage infrastructure and create unsafe driving conditions. This case study further demonstrates a mapping technique that utilizes a 30-year inventory of Landsat satellite imagery. Icings were mapped every year from a late-spring image and were analyzed in a Geographic Information System to determine their distribution and return frequency. Nearly 200 icings were mapped, with icing density and dynamics varying depending on ecoregion. This geoscientific data may be utilized for planning land-based transportation infrastructure.