Glacier Surface Velocity Retrieval Using D-InSAR and Offset Tracking Techniques Applied to Ascending and Descending Passes of Sentinel-1 Data for Southern Ellesmere Ice Caps, Canadian Arctic

Abstract

Abstract:The Terrain Observation by Progressive Scans (TOPS) acquisition mode of the Sentinel-1 mission provides a wide coverage per acquisition with resolutions of 5 m in range and 20 m in azimuth, which makes this acquisition mode attractive for glacier velocity monitoring. Here, we retrieve surface velocities from the southern Ellesmere Island ice caps (Canadian Arctic) using both offset tracking and Differential Interferometric Synthetic Aperture Radar (D-InSAR) techniques and combining ascending and descending passes. We optimise the offset tracking technique by omitting the azimuth offsets. By doing so, we are able to improve the final resolution of the velocity product, as Sentinel-1 shows a lower resolution in the azimuth direction. Simultaneously, we avoid the undesired ionospheric effect manifested in the data as azimuth streaks. The D-InSAR technique shows its merits when applied to slow-moving areas, while offset tracking is more suitable for fast-moving areas. This research shows that the methods used here are complementary and the use of both to determine glacier velocities is better than only using one or the other. We observe glacier surface velocities of up to 1200 m year −1 for the fastest tidewater glaciers. The land-terminating glaciers show typical velocities between 12 and 33 m year −1 , though with peaks up to 150 m year −1 in narrowing zones of the confining valleys.

Mass Balance Assessment of the Amery Ice Shelf Basin, East Antarctica

“…Earth and Space Science (Figure 4) and the grounding line (Figure 5b), derived from our results agree well with other results. Overall, our analysis of velocity over the rock outcrops indicates that the uncertainty in the velocity is 10 m/year, which is comparable to the errors of the Sentinel-1-derived ice velocity reported in other studies (Mouginot et al, 2017;Nagler et al, 2015;Sánchez-Gámez & Navarro, 2017).…”

Monitoring and Analyzing Mountain Glacier Surface Movement Using SAR Data and a Terrestrial Laser Scanner: A Case Study of the Himalayas North Slope Glacier Area

“…To solve the limitation that DInSAR can only estimate light-of-sight deformation, Gray et al presented a SAR image registration method that can extract displacements in the azimuth and range directions of glaciers [12]. Based on the intensity information of SAR images, this method, which can be called the offset tracking technique (or speckle tracking technique), is better able to resist decorrelation [13][14][15]. Another SAR method, proposed by Bechor et al in 2006, is multi-aperture interferometry (MAI), which utilizes the phase information of SAR images similarly to DInSAR, providing a way to extract high-accuracy displacements in azimuth direction [16].…”

The Status of Earth Observation Techniques in Monitoring High Mountain Environments at the Example of Pasterze Glacier, Austria: Data, Methods, Accuracies, Processes, and Scales

“…However due to snowfall, snowdrift, and melting, which leads to temporal decorrelation, mainly data with short repeat-pass were used [81]. To estimate surface velocities of glaciers, DInSAR using Sentinel-1 data was applied, exhibiting low deformation rates and therefore low decorrelation [82].…”