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

Schellenberger, Thomas; Wychen, Wesley Van; Copland, Luke; Kääb, Andreas; Gray, Alistair

doi:10.3390/rs8090785

Cited by 22 publications

(8 citation statements)

References 35 publications

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“…Short and Gray, 2005; Van Wychen and others, 2014, 2016), and has been shown to provide comparable results to those determined by commercial software packages (e.g. GAMMA InSAR) (Schellenberger and others, 2016). Image pairs were initially coregistered either manually (RADARSAT-1), or by calculating offsets from orbital parameters (RADARSAT-2).…”

Section: Methodsmentioning

confidence: 72%

Seven decades of uninterrupted advance of Good Friday Glacier, Axel Heiberg Island, Arctic Canada

et al. 2019

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Previous studies reported that Good Friday Glacier had been actively surging in the 1950–60s, 1990s and again in 2000–15. Based on observations of terminus position change from air photos and satellite imagery, we fill the gaps between previous studies and conclude that the glacier has been advancing continuously since 1959. Ice surface velocities extracted from optical and synthetic aperture radar satellite images show higher flow rates than on most other marine-terminating glaciers in the region. This behaviour contrasts with the regional trend of glacier retreat over this period. Possible explanations involve a delayed response to positive mass-balance conditions of the Little Ice Age, or a dynamic instability. There is, however, insufficient evidence to attribute this behaviour to classical glacier surging as suggested in previous studies. Based on present-day ice velocity and glacier geometry patterns in the terminus region, we reconstruct the evolution of ice motion throughout the advance, and suggest that what has previously been interpreted as a surge, may instead have been a localised response to small-scale perturbations in bedrock topography.

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Section: Methodsmentioning

confidence: 72%

Seven decades of uninterrupted advance of Good Friday Glacier, Axel Heiberg Island, Arctic Canada

et al. 2019

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“…GAMMA software (Wegmüller and others, 2015) (GAMMA Remote Sensing AG, Gümlingen, Switzerland) was used for processing the Sentinel-1 SAR acquisitions (Strozzi and others, 2002; Schellenberger and others, 2016) with the intensity offset-tracking algorithm applied exclusively. Sentinel-1 TOPS mode images need to be co-registered before any offset tracking or interferometric algorithms are applied.…”

Section: Methodsmentioning

confidence: 99%

Intra- and inter-annual variability in dynamic discharge from the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian Arctic, and its role in modulating mass balance

et al. 2019

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We determined ice velocities for the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian Arctic, during November 2016–November 2017, by feature-tracking 54 pairs of Sentinel-1 synthetic-aperture radar images. Seasonal velocity variations with amplitudes up to 10% of the yearly-averaged velocity were observed. Shorter-term (<15 d) intra-annual velocity variations had average and maximum deviations from the annual mean of up to 16 and 32%, respectively. This indicates the errors that could be incurred if ice discharge values determined from a single pair of images were extrapolated to the whole year. Average ice discharge for 2016–2017 was 1.93 ± 0.12 Gt a−1. The difference from an estimate of ~ 1.4 Gt a−1 for 2003–2009 was attributed to the initiation of ice stream flow in Basin BC. The total geodetic mass balance over 2012–2016 was − 1.72 ± 0.67 Gt a−1 (− 0.31 ± 0.12 m w.e. a−1). The climatic mass balance was not significantly different from zero, at 0.21 ± 0.68 Gt a−1 (0.04 ± 0.12 m w.e. a−1), and has remained near zero at decadal-scale for the last four decades. Therefore, the total mass balance has been controlled largely by variations in ice discharge, whose long-term changes do not appear to have responded to environmental changes but to the intrinsic characteristics of the ice cap governing tidewater glacier dynamics.

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“…We apply a custom-written MATLAB™ speckle tracking script to RADARSAT-2 imagery to determine the velocity structure of Devon Ice Cap, as has been applied in previous studies of glacier motion in the Canadian Arctic (Short and Gray, 2004, 2005; Van Wychen and others, 2012, 2014, 2015, 2016) and Svalbard (Schellenberger and others, 2016). Here, we use RADARSAT-2 single-look complex (SLC) Fine and Wide Fine, and Ultrafine and Wide Ultrafine, beam mode datasets all of which perform well for determining ice motion at the scale of Devon Ice Cap (Van Wychen and others, 2012, 2014, 2016).…”

Section: Methodsmentioning

confidence: 99%

Variability in ice motion and dynamic discharge from Devon Ice Cap, Nunavut, Canada

et al. 2017

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Feature 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−1for Devon Ice Cap. The Belcher Glacier is becoming a larger source of mass loss via ice discharge.

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

Cited by 22 publications

References 35 publications

Seven decades of uninterrupted advance of Good Friday Glacier, Axel Heiberg Island, Arctic Canada

Seven decades of uninterrupted advance of Good Friday Glacier, Axel Heiberg Island, Arctic Canada

Intra- and inter-annual variability in dynamic discharge from the Academy of Sciences Ice Cap, Severnaya Zemlya, Russian Arctic, and its role in modulating mass balance

Variability in ice motion and dynamic discharge from Devon Ice Cap, Nunavut, Canada

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