| Popis: |
This study presents surface ice motion patterns across Devon Ice Cap, with a particular focus on the Belcher Glacier drainage basin. Between summer 2007 and summer 2009, continuous differential GPS (dGPS) measurements were made to determine the motion at points along the centerline of the Belcher Glacier with ∼cm accuracy. In summer 2008, marker stakes were set out on all accessible tributaries in the Belcher basin, with each stake being surveyed with dGPS several times throughout the season. Using synthetic aperture radar (SAR) speckle tracking techniques new velocity maps were produced of seasonal changes in ice motion for the Belcher Glacier. These were validated against the field dGPS results. Ground penetrating radar (GPR) was used to determine the ice depths of each tributary basin in the Belcher Glacier study region. These ice depths are combined with velocities derived from the speckle tracking results to create flux gates which allow for estimates of total ice discharge for the Belcher basin. These volume estimates can be used to improve mass loss estimates for future modeling of Devon Ice Cap. The velocity results are compared to the work of Burgess et al (2005), who provided flow dynamics and mass loss from the Devon Ice Cap and Belcher Glacier systems using interferometry and speckle tracking of ERS 1/2 data from the mid-1990s and Radarsat-1 data from 2000. These comparisons reveal higher ice velocities on a large glacier in the southeast part of the ice cap (Southeast2 Glacier), which agrees with recent thickening of the stagnant ice into which the glacier drains. |
