Spatial and temporal variation of ice motion and ice flux from Devon Ice Cap, Nunavut, Canada

Abstract

Speckle tracking of repeat RADARSAT-2 fine-beam imagery acquired over 24 day periods in March 2009 allowed the creation of updated surface motion maps for the entire Devon Ice Cap, Canada. Error analysis indicates that speckle tracking can determine ice motion to an accuracy of ~5 ma-1. Comparisons with earlier velocity maps from the mid-1990s and 2000 reveal velocity patterns that largely agree with flow regimes described previously. However, motion determined along East5 Glacier indicates an increase in surface velocities between the studies. Additionally, Southeast2 Glacier has significantly accelerated over the past decade, with velocities greater in 2009 than in the early 1990s along almost the entire length of the glacier. This is likely indicative of a surge. Present-day total mass loss from Devon Ice Cap due to iceberg calving is calculated as 0.40 ± 0.09 Gta-1, similar to that reported by Burgess and others (2005), with Belcher Glacier accounting for ~42% of the entire loss.

Flow and structure in a dendritic glacier with bedrock steps

“…Manual verification of the velocities was undertaken in ArcGIS™ using the methodology of Van Wychen and others (2012); where (1) flow vectors should be constrained by topography and should be aligned with surface flow features (medial moraines); (2) velocities should be faster along the glacier centreline than near the margins due to lateral friction; and (3) adjacent flow vectors should show consistency in both the direction and magnitude of displacement. Identified mismatches were removed from the dataset and the velocities were then resampled to a 100 m 2 resolution raster surface using an inverse distance weighting interpolation and clipped to the extent of the Shackleton Glacier basin.…”

Circum-Arctic Changes in the Flow of Glaciers and Ice Caps from Satellite SAR Data between the 1990s and 2017

“…For example, over the Canadian Arctic [11] analysed velocities of the Devon Ice Cap, Van Wychen, W. et al [12] presented flow velocities and discharge for all of the glaciers and ice caps on Baffin and Bylot islands, and Van Wychen, W. et al [13] studied multi-temporal trends in velocity and discharge for Ellesmere and Axel Heiberg Islands. This region was also investigated by [8] with a focus on mass budgets (both surface and calving) for the 1991-2015 period.…”

An Inter-Comparison of Techniques for Determining Velocities of Maritime Arctic Glaciers, Svalbard, Using Radarsat-2 Wide Fine Mode Data

“…This is mainly because surface features and speckle patterns change rapidly in the maritime environment of Svalbard. In dryer regions such as the Canadian arctic, more favourable conditions also allow the detection of small displacements [6][7][8].…”

“…The second tracking method used in this study is a custom written MATLAB offset and speckle tracking script [33]; hereafter referred to as the GRAY method, which has been utilized to derive glacier velocities for the Canadian High Arctic [6][7][8] and the Yukon/Alaska region [34]. The tracking process started with Radarsat-2 Single-Look Complex (SLC) data.…”

“…This is especially true for marine terminating glaciers, where measurements of ice motion can be combined with ice thickness information to determine frontal ablation rates, and hence the contribution of glaciers and ice sheets to global sea level rise. In light of this, in recent years there has been a concerted effort to map glacier dynamics at the regional scale for many of the glaciated regions of the world: Antarctica [1], the Greenland Ice Sheet [2,3], the majority of Alaskan glaciers [4,5], the Canadian High Arctic [6][7][8] and South America [9][10][11].…”