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TitleCharacterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada
AuthorVanWychen, W; Davis, J; Burgess, D O; Copland, L; Gray, L; Sharp, M; Dowdeswell, J
SourceJournal of Geophysical Research Earth Surface vol. 121, issue 1, 2016 p. 39-63,
Alt SeriesEarth Sciences Sector, Contribution Series 20150295
PublisherAmerican Geophysical Union
Mediapaper; on-line; digital
File formatpdf
NTS120B; 120C; 120D; 120F; 120E; 120G; 340; 39; 49; 59F; 59G; 59H; 59E; 560A; 560B; 560D
AreaAxel Heiberg Island; Ellesmere Island
Lat/Long WENS -98.0000 -80.0000 82.0000 76.0000
Subjectsremote sensing; LANDSAT imagery; glacier surveys; glaciers; glacial surges; ice flow; discharge rates; RADARSAT-1; RADARSAT-2; Trinity glacier; Wykeham glacier; radar velocity mapping
Illustrationssatellite images; location maps; tables; graphs
ProgramEssential Climate Variable Monitoring, Climate Change Geoscience
AbstractLandsat 7 and RADARSAT-1/RADARSAT-2 satellite images are used to produce the most comprehensive record of glacier motion in the Canadian High Arctic to date and to characterize spatial and temporal variability in ice flow over the past ~15 years. This allows us to assess whether dynamically driven glacier change can be attributed to "surging" or "pulsing," or whether other mechanisms are involved. RADAR velocity mapping allows annual regional dynamic discharge (iceberg calving) to be calculated for 2000 and the period 2011-2015 (yielding a mean regional discharge of 2.21±0.68 Gt a-1), and velocities derived from feature tracking of optical imagery allow for annual dynamic discharge to be calculated for select glaciers from 1999 to 2010. Since ~2011, several of the major tidewater-terminating glaciers within the region have decelerated and their dynamic discharge has decreased. Trinity and Wykeham Glaciers (Prince of Wales Icefield) represent a notable departure from this pattern as they have generally accelerated over the study period. The resulting increase in dynamic discharge from these glaciers entirely compensates (within error limits) for the decrease in discharge from the other tidewater glaciers across the study region. These two glaciers accounted for ~62% of total regional dynamic discharge in winter 2015 (compared to ~22% in 2000), demonstrating that total ice discharge from the Canadian High Arctic can be sensitive to variations in flow of just a few tidewater glaciers.
Summary(Plain Language Summary, not published)
Glacier mass loss due to ice-berg calving is an important form of ablation from ice caps in the Canadian high Arctic being second only to mass loss due to summer melting. Until recently however, the rate of calving flux from this region has been poorly quantified. This paper provides the most complete estimate calving flux to date from ice velocity fields derived using RADARSAT-2 and Landsat imagery, along with all available ice thickness data to date. Results from this study indicate that Canadian ice caps lost ~2.2 Gigatons per year over the past 15 years. Results indicate that total ice discharge from the Canadian High Arctic is very sensitive to variations in flow of just a few individual calving glaciers.