Combined Usage of TanDEM-X and CryoSat-2 for Generating a High Resolution Digital Elevation Model of Fast Moving Ice Stream and Its Application in Grounding Line Estimation

Kim, Seung Hee; Kim, Duk‐jin

doi:10.3390/rs9020176

Cited by 7 publications

(3 citation statements)

References 39 publications

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“…We determined the local topographic variation of the floating ice shelf by differencing pairs of independently-generated TanDEM-X DEMs of the Thwaites ice shelf. The procedure of DEM-generation by calculating interferograms with two bi-static TanDEM-X data is explained in more detail by Kim and Kim [19]. TanDEM-X data were acquired on 10 June 2012, 29 June 2012, and 27 June 2013, allowing us to generate two sets of deformation maps.…”

Section: High-resolution Deformation Mapmentioning

confidence: 99%

Progressive Degradation of an Ice Rumple in the Thwaites Ice Shelf, Antarctica, as Observed from High-Resolution Digital Elevation Models

Kim

2018

Remote Sensing

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Ice rumples are locally-grounded features of flowing ice shelves, elevated tens of meters above the surrounding surface. These features may significantly impact the dynamics of ice-shelf grounding lines, which are strongly related to shelf stability. In this study, we used TanDEM-X data to construct high-resolution DEMs of the Thwaites ice shelf in West Antarctica from 2011 to 2013. We also generated surface deformation maps which allowed us to detect and monitor the elevation changes of an ice rumple that appeared sometime between the observations of a grounding line of the Thwaites glacier using Double-Differential Interferometric SAR (DDInSAR) in 1996 and 2011. The observed degradation of the ice rumple during 2011-2013 may be related to a loss of contact with the underlying bathymetry caused by the thinning of the ice shelf. We subsequently used a viscoelastic deformation model with a finite spherical pressure source to reproduce the surface expression of the ice rumple. Global optimization allowed us to fit the model to the observed deformation map, producing reasonable estimates of the ice thickness at the center of the pressure source. Our conclusion is that combining the use of multiple high-resolution DEMs and the simple viscoelastic deformation model is feasible for observing and understanding the transient nature of small ice rumples, with implications for monitoring ice shelf stability.

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Section: High-resolution Deformation Mapmentioning

confidence: 99%

Progressive Degradation of an Ice Rumple in the Thwaites Ice Shelf, Antarctica, as Observed from High-Resolution Digital Elevation Models

Kim

2018

Remote Sensing

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“…The height of ambiguity is inversely proportional to the perpendicular baseline in the radar geometry. Nearly simultaneous observations using TanDEM-X and close flight formation in a helical orbit facilitates a very high coherence (e.g., a reduction in temporal decorrelation and atmospheric artifacts), even on a rapidly varying surface such as an ice stream [24]. However, a moderate height of ambiguity (>30 m) from the short perpendicular baseline in the TanDEM-X operational mode might not be suitable to represent detailed topographic features in a low gradient area, such as a tidal flat or a glacier.…”

Section: Introductionmentioning

confidence: 99%

Using TanDEM-X Pursuit Monostatic Observations with a Large Perpendicular Baseline to Extract Glacial Topography

et al. 2018

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Space-based Interferometric Synthetic Aperture Radar (InSAR) applications have been widely used to monitor the cryosphere over past decades. Owing to temporal decorrelation, interferometric coherence often severely degrades on fast moving glaciers. TanDEM-X observations can overcome the temporal decorrelation because of their simultaneous measurements by two satellite constellations. In this study, we used the TanDEM-X pursuit monostatic mode with large baseline formation following a scientific phase timeline to develop highly precise topographic elevation models of the Petermann Glacier of Northwest Greenland. The large baseline provided the advantage of extracting topographic information over low relief areas, such as the surface of a glacier. As expected, coherent interferometric phases (>0.8) were well maintained over the glaciers, despite their fast movement, due to the nearly simultaneous TanDEM-X measurements. The height ambiguity, which was defined as the altitude difference corresponding to a 2π phase change of the flattened interferogram, of the dataset was 10.63 m, which was favorable for extracting topography in a low relief region. We validated the TanDEM-X derived glacial topography by comparing it to the SAR/Interferometric radar altimeter observations acquired by CryoSat-2 and the IceBridge Airborne Topographic Mapper laser altimeter measurements. Both observations showed very good correlation within a few meters of the offsets (−12.5~−3.1 m), with respect to the derived glacial topography. Routine TanDEM-X observations will be very useful to better understand the dynamics of glacial movements and topographic change.

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“…The height of ambiguity is inverse proportional to the perpendicular baseline in the radar geometry. Nearly simultaneous observations using TanDEM-X and close flight formation in a helical orbit facilitates very high coherence (e.g., a reduction in temporal decorrelation and atmospheric artifacts) even on a rapidly varying surface such as an ice stream [24]. However, moderate height of ambiguity (>30 m) from the short perpendicular baseline in the TanDEM-X operational mode might not be suitable to represent detailed topographic features in a low gradient area such as a tidal flat or glacier.…”

Section: Introductionmentioning

confidence: 99%

Using Tandem-X Science Phase Observations to Extract Glacial Topography

Hong¹,

Wdowinski²,

Amelung³

et al. 2018

Preprint

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Space-based Interferometric Synthetic Aperture Radar (InSAR) applications have been widely used to monitor the cryosphere over past decades. Because of temporal decorrelation, interferometric coherence often severely degrades on fast moving glaciers. In addition, higher sensitivity ambiguity occurs in large baseline configurations, which are needed for extracting topographic information over low relief areas such as the surface of a glacier. TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) observations, which overcome the temporal decorrelation because of their simultaneous measurements by two satellite constellations, have used a short baseline sufficient for generation of excellent digital elevation models in most locations around the world. However, it remains difficult to estimate detailed topographic characteristics over low slope glacier surfaces because of the relatively less sensitive height ambiguity from the small baselines. In this study, we used the TanDEM-X pursuit monostatic mode with large baseline formation following a scientific phase timeline to develop highly sensitive topographic elevation models of the Petermann Glacier of Northwest Greenland. As expected, coherent interferometric phases (> 0.8) were well maintained over the glaciers despite their fast movement thanks to the nearly simultaneous TanDEM‐X measurements. The height ambiguity, which defined as the altitude difference correspondent to phase change of flattened interferogram, of the dataset was 10.63 m, which is favorable for extracting topography in a low relief region. We validated the TanDEM‐X derived glacial topography by comparing it to the SAR/Interferometric radar altimeter observations acquired by CryoSat‐2 and the IceBridge Airborne Topographic Mapper laser altimeter measurements. Both observations showed very good correlation within a few meters of the offsets (‐12.5 – ‐3.1 m) with respect to the derived glacial topography. Because of highly sensitive ambiguity, we could successfully extract detailed geomorphological features on the glaciers. Routine TanDEM-X observations will be very useful to better understand the dynamics of glacial movements and topographic change.

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Combined Usage of TanDEM-X and CryoSat-2 for Generating a High Resolution Digital Elevation Model of Fast Moving Ice Stream and Its Application in Grounding Line Estimation

Cited by 7 publications

References 39 publications

Progressive Degradation of an Ice Rumple in the Thwaites Ice Shelf, Antarctica, as Observed from High-Resolution Digital Elevation Models

Progressive Degradation of an Ice Rumple in the Thwaites Ice Shelf, Antarctica, as Observed from High-Resolution Digital Elevation Models

Using TanDEM-X Pursuit Monostatic Observations with a Large Perpendicular Baseline to Extract Glacial Topography

Using Tandem-X Science Phase Observations to Extract Glacial Topography

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