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TitleVariability in ice motion and dynamic discharge from Devon Ice Cap, Nunavut, Canada
AuthorVan Wychen, W; Davis, J; Copland, L; Burgess, D O; Gray, L; Sharp, M; Dowdeswell, J A; Benham, T J
SourceJournal of Glaciology vol. 63, issue 239, 2017 p. 436-449, (Open Access)
Alt SeriesEarth Sciences Sector, Contribution Series 20150442
PublisherCambridge University Press (CUP)
Mediapaper; on-line; digital
File formatpdf
NTS38F/13; 48E; 48F/09; 48F/16; 48G/01; 48G/08; 48G/09; 48G/16; 48H
AreaDevon Ice Cap; Devon Island; Canadian Arctic Archipelago
Lat/Long WENS -85.0000 -79.5000 76.0000 74.5000
Subjectssurficial geology/geomorphology; geophysics; environmental geology; Nature and Environment; glaciology; glaciers; ice movement; ice flow; displacement; ice margins; remote sensing; satellite imagery; coastal environment; ice thickness; climate; temperature; flow regimes; mapping techniques; ice caps; speckle tracking; Landsat-7 ETM+; RADARSAT-2; glacier velocities; dynamic ice discharge; mass loss; climate change; glacier bed profiles; classification
Illustrationslocation maps; geoscientific sketch maps; tables; graphs; time series; profiles
ProgramClimate Change Geoscience, Essential Climate Variable Monitoring
Released2017 02 07
AbstractFeature tracking of approximately annually separated Landsat-7 ETM+ imagery acquired from 1999 to 2010 and speckle tracking of 24-day separated RADARSAT-2 imagery acquired from 2009 to 2015 reveal that motion of the major tidewater glaciers of Devon Ice Cap is more variable than previously described. The flow of almost half (six of 14) of the outlet glaciers slowed over the observation period, while that of the terminus regions of three of 14 of the glaciers sped up in the most recent years of observation. The North Croker Bay Glacier of southern Devon Ice Cap showed the greatest variability in motion, oscillating between multi-year (three or more) periods of slower and faster flow and exhibited a pattern of velocity variability that is different from that of the rest of the ice cap's outlet glaciers. Comparisons between areas of dynamic variability and glacier bed topography indicate that velocity variability is largely restricted to regions where the glacier bed is grounded below sea level. Derived velocities are combined with measurements of ice thickness at the fronts of tidewater glacier to determine a mean annual (2009; 2011-15) dynamic ice discharge of 0.41 ± 0.11 Gt/a for Devon Ice Cap. The Belcher Glacier is becoming a larger source of mass loss via ice discharge.
Summary(Plain Language Summary, not published)
This study measures the variability in the rate of flow of several tidewater glaciers that drain ice caps in the Canadian high Arctic. Variations in flow of tidewater terminating glaciers influences the volume of glacier ice transferred directly to oceans, thus impacting both total ice mass change and global sea-level. Thus, quantifying variability over a 14 year time period (ie, 2000 ¿ 2014) provides important information on the representativeness of single velocity measurements for calculating long-term calving rates.