Analysis of the 1993-95 Bering Glacier (Alaska) surge using differential SAR interferometry

AbstractDifferential spaceborne radar interferometry observations of West Bagley Icefield are used to measure surface velocity and topography. Bagley Icefield is the accumulation area fur Bering Glacier which surged in two phases from spring 1993 through summer 1905. The observations presented are based on data collected during the winter of 1992, prior to the surge, and during winter 1994 while the surge was in full progress. Both observation intervals correspond to 3 day repeat orbit phases of the ERS-I C-band SAR. This paper gives an overview of the algorithms used to derive surface-velocity vector fields and topography for valley glaciers from SAR images. The resulting high-resolution velocity data clearly show West Bagley Icefield accelerating from its quiescent pre-surge velocity by a factor of 2.7 in response to the Bering Glacier surge. Persistence of lnterfero-metric phase coherence and the relatively moderate degree of acceleration on the western arm of Bagley Icefield suggest that the velocity increase may have been caused by increased longitudinal stress gradients resulting from coupling to the surging main trunk of Bering Glacier.

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Offset tracking procedure applied to high resolution SAR data on Viedma Glacier, Patagonian Andes, Argentina

Advances in Geosciences ◽

10.5194/adgeo-35-7-2013 ◽

2013 ◽

Vol 35 ◽

pp. 7-13 ◽

Cited By ~ 18

Author(s):

N. Riveros ◽

L. Euillades ◽

P. Euillades ◽

S. Moreiras ◽

S. Balbarani

Keyword(s):

High Resolution ◽

Large Study ◽

Sar Interferometry ◽

Santa Cruz ◽

Sar Images ◽

Ice Flow ◽

Displacement Maps ◽

Patagonian Andes ◽

Offset Tracking ◽

Differential Sar Interferometry

Abstract. Main aim of this work is to explore the suitability of high resolution SAR images for measuring ice flow velocity within glaciers. Available techniques for this purpose are Differential SAR Interferometry (DInSAR) and Offset Tracking. The former, although theoretically much more precise, is frequently limited by coherence loss (or lacking of coherence) in glacier environment. The latter constitutes an alternative that works well when displacements are large. Study area is the Viedma Glacier (Santa Cruz, Argentina), one of the largest uncovered ice bodies in the South Patagonian Ice (SPI). High resolution COSMO-SkyMed (CSK) acquisitions were processed by estimating range and azimuth offset fields. Useful results, consisting in displacement maps showing areas with different fast-flowing units, were obtained by Offset Tracking processing.

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Application of Differential SAR Interferometry in Mining Subsidence Monitoring

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.864-867.2735 ◽

2013 ◽

Vol 864-867 ◽

pp. 2735-2738

Author(s):

Wen Hai Xia ◽

Yuan Yuan Li

Keyword(s):

High Spatial Resolution ◽

Mining Subsidence ◽

Sar Interferometry ◽

Sar Images ◽

Synthetic Aperture Radar Interferometry ◽

Persistent Scatterer ◽

Technical Issues ◽

Subsidence Monitoring ◽

Differential Sar Interferometry ◽

Selection Of

Differential synthetic aperture radar Interferometry has been widely applied to monitor mining subsidence for its high spatial resolution, competent accuracy and wide coverage. In this paper, we introduce the principles of InSAR, discuss several key technical issues in mining subsidence monitoring, including selection of SAR images, advanced algorithms for phase unwrapping and Persistent Scatterer InSAR technique.

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Surge dynamics on Bering Glacier, Alaska, in 2008–2011

The Cryosphere Discussions ◽

10.5194/tcd-6-1181-2012 ◽

2012 ◽

Vol 6 (2) ◽

pp. 1181-1204 ◽

Cited By ~ 5

Author(s):

E. W. Burgess ◽

R. R. Forster ◽

C. F. Larsen ◽

M. Braun

Keyword(s):

Surface Velocity ◽

Second Phase ◽

Surface Elevation Change ◽

Bering Glacier ◽

Elevation Data ◽

Glacier Length ◽

Two Phases ◽

The University ◽

Accelerated Flow ◽

Offset Tracking

Abstract. A 2008–2011 surge of Bering Glacier, Alaska is examined using observations of surface velocity and surface elevation change. Velocity measurements are obtained using synthetic aperture radar (SAR) offset tracking and elevation data are obtained from the University of Alaska Fairbanks LiDAR altimetry program. Bering Glacier began to surge in May 2008 and had two phases of accelerated flow. The first phase accelerated progressively for at least 10 months and reached peak observed velocities of ~7 m d−1. Results suggest that during the quiescent phase, prior to the surge, periods of accelerated flow increased driving stresses up to 70% in a ~10 km-long section of the Lower Bering. When the first phase of the surge initiated, synchronous acceleration occurred throughout much of the glacier length, indicating widespread pressurization of the bed, but the largest accelerations initiated at the location where driving stress built up during quiescence. From there, rapid flow velocities propagated upstream and downstream across much of the glacier length and transpired as small, transient and unorganized propagation fronts. The second phase occurred in 2011 and was of comparable scale to the surge in 1993–1995, with velocities exceeding 9 m d−1 or ~18 times quiescent velocities.

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Ice-dynamic conditions of Shirase Glacier, Antarctica, inferred from ERS SAR interferometry

Journal of Glaciology ◽

10.3189/172756502781831115 ◽

2002 ◽

Vol 48 (163) ◽

pp. 559-565 ◽

Cited By ~ 30

Author(s):

Frank Pattyn ◽

Dominique Derauw

Keyword(s):

Large Scale ◽

Drainage Basin ◽

Surface Strain ◽

Force Balance ◽

Phase Correlation ◽

Sar Interferometry ◽

Surface Velocity ◽

Sar Images ◽

Outlet Glacier ◽

Grounding Line

AbstractThe surface velocity field of Shirase Glacier, a fast-flowing East Antarctic outlet glacier, is determined from ERS synthetic aperture radar (SAR) images by means of speckle tracking using phase correlation, a technique which matches small image kernels of two complex SAR images by maximization of the local coherence. Velocity estimates are used to calculate surface strain rates, which are then used to calculate the large-scale, vertically integrated force balance and to determine the major stress components resisting the driving stress. For the whole glacier system, the driving stress is largely balanced by the basal drag, but with contributions from lateral drag up to 15% of the driving stress at the grounding line. Longitudinal stress gradients have only local importance to the balance of forces, limited to an area of a few square kilometers near the grounding line, where they resist the driving stress. In the grounded part of the glacier, >90% of the total ice velocity is due to basal sliding. Comparison with a balance-flux distribution of the Antarctic ice sheet suggests that the glacier in the downstream part of the Shirase drainage basin is close to equilibrium, showing a slight negative imbalance.

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Modified four-pass differential SAR interferometry for estimating mountain glacier surface velocity fields

Remote Sensing Letters ◽

10.1080/2150704x.2015.1094588 ◽

2015 ◽

Vol 7 (1) ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Guang Liu ◽

Huadong Guo ◽

Huanyin Yue ◽

Zbigniew Perski ◽

Shiyong Yan ◽

...

Keyword(s):

Velocity Fields ◽

Sar Interferometry ◽

Surface Velocity ◽

Glacier Surface ◽

Mountain Glacier ◽

Differential Sar Interferometry

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Combining SAR interferometry and the equation of continuity to estimate the three-dimensional glacier surface-velocity vector

Journal of Glaciology ◽

10.3189/s0022143000001398 ◽

1999 ◽

Vol 45 (151) ◽

pp. 533-538 ◽

Cited By ~ 2

Author(s):

Niels Reeh ◽

Søren Nørvang Madsen ◽

Johan Jakob Mohr

Keyword(s):

Steady State ◽

Mass Balance ◽

Vertical Velocity ◽

Velocity Vector ◽

Thickness Distribution ◽

Vertical Surface ◽

Horizontal Velocity ◽

Sar Interferometry ◽

Surface Velocity ◽

Ice Thickness

AbstractUntil now, an assumption of surface-parallel glacier flow has been used to express the vertical velocity component in terms of the horizontal velocity vector, permitting all three velocity components to be determined from synthetic aperture radar interferometry. We discuss this assumption, which neglects the influence of the local mass balance and a possible contribution to the vertical velocity arising if the glacier is not in steady state. We find that the mass-balance contribution to the vertical surface velocity is not always negligible as compared to the surface-slope contribution. Moreover, the vertical velocity contribution arising if the ice sheet is not in steady state can be significant. We apply the principle of mass conservation to derive an equation relating the vertical surface velocity to the horizontal velocity vector. This equation, valid for both steady-state and non-steady-state conditions, depends on the ice-thickness distribution. Replacing the surface-parallel-flow assumption with a correct relationship between the surface velocity components requires knowledge of additional quantities such as surface mass balance or ice thickness.

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Meso- and microscale sea-ice motion in the East Siberian Sea as determined from ERS-1 SAR Data

Journal of Glaciology ◽

10.1017/s0022143000001878 ◽

1999 ◽

Vol 45 (150) ◽

pp. 370-383 ◽

Cited By ~ 7

Author(s):

Kim Morris ◽

Shusun Li ◽

Martin Jeffries

Keyword(s):

Time Series ◽

Sea Ice ◽

Large Scale ◽

Vector Fields ◽

Lateral Displacement ◽

Motion Vector ◽

Sar Interferometry ◽

East Siberian Sea ◽

Pack Ice ◽

Sar Data

Abstract Synthetic aperture radar- (SAR-)derived ice-motion vectors and SAR interferometry were used to study the sea-ice conditions in the region between the coast and 75° N (~ 560 km) in the East Siberian Sea in the vicinity of the Kolyma River. ERS-1 SAR data were acquired between 24 December 1993 and 30 March 1994 during the 3 day repeat Ice Phase of the satellite. The time series of the ice-motion vector fields revealed rapid (3 day) changes in the direction and displacement of the pack ice. Longer-term (≥ 1 month) trends also emerged which were related to changes in large-scale atmospheric circulation. On the basis of this time series, three sea-ice zones were identified: the near-shore, stationary-ice zone; a transitional-ice zone;and the pack-ice zone. Three 3 day interval and one 9 day interval interferometric sets (amplitude, correlation and phase diagrams) were generated for the end of December, the begining of February and mid-March. They revealed that the stationary-ice zone adjacent to the coast is in constant motion, primarily by lateral displacement, bending, tilting and rotation induced by atmospheric/oceanic forcing. The interferogram patterns change through time as the sea ice becomes thicker and a network of cracks becomes established in the ice cover. It was found that the major features in the interferograms were spatially correlated with sea-ice deformation features (cracks and ridges) and major discontinuities in ice thickness.

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High-Quality Pixel Selection Applied for Natural Scenes in GB-SAR Interferometry

Remote Sensing ◽

10.3390/rs13091617 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1617

Author(s):

Yunkai Deng ◽

Weiming Tian ◽

Ting Xiao ◽

Cheng Hu ◽

Hong Yang

Keyword(s):

Phase Measurement ◽

High Amplitude ◽

Sar Interferometry ◽

Spatial Density ◽

Natural Scenes ◽

Sar Images ◽

High Quality ◽

Temporal Phase ◽

Permanent Scatterers ◽

High Phase

Phase analysis based on high-quality pixel (HQP) is crucial to ensure the measurement accuracy of ground-based SAR (GB-SAR). The amplitude dispersion (ADI) criterion has been widely applied to identify pixels with high amplitude stability, i.e., permanent scatterers (PSs), which typically are point-wise scatterers such as stones or man-made structures. However, the PS number in natural scenes is few and limits the GB-SAR applications. This paper proposes an improved method to take HQP selection applied for natural scenes in GB-SAR interferometry. In order to increase the spatial density of HQP for phase measurement, three types of HQPs including PS, quasi-permanent scatter (QPS), and distributed scatter (DS), are selected with different criteria. The ADI method is firstly utilized to take PS selection. To select those pixels with high phase stability but moderate amplitude stability, the temporal phase coherence (TPC) is defined. Those pixels with moderate ADI values and high TPC are selected as QPSs. Then the feasibility of the DS technique is explored. To validate the feasibility of the proposed method, 2370 GB-SAR images of a natural slope are processed. Experimental results prove that the HQP number could be significantly increased while slightly sacrificing phase quality.

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