Mapping Complete Three-Dimensional Ice Velocities by Integrating Multi-Baseline and Multi-Aperture InSAR Measurements: A Case Study of the Grove Mountains Area, East Antarctic

The Antarctic is one of the most sensitive areas to climate change, and ice velocity is a fundamental parameter for quantitatively assessing the glacier mass balance. Interferometric synthetic aperture radar (InSAR), a powerful tool for monitoring surface deformation with the advantages of having high precision and wide coverage, has been widely used in determining ice velocity in the Antarctic. However, the mapping of complete three-dimensional (3D) ice velocities is greatly limited by the imaging geometries and digital elevation model (DEM)-induced errors. In this study, we propose the integration of multibaseline and multiaperture InSAR measurements from the ENVISAT ASAR datasets to derive complete 3D ice velocities in the Grove Mountains area of the Antarctic. The results show that the estimated complete 3D ice velocities are in good agreement with MEaSUREs and GPS observations. Compared with the conventional 2D and quasi-3D ice velocities, the complete 3D ice velocities can effectively eliminate the effects of DEM errors and elevation changes and are also capable of retrieving the thickness change of the ice, which provides important information on the origin of mass transition.

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Antarctic Ice-Sheet Topography and Surface-Bedrock Relationships

Annals of Glaciology ◽

10.1017/s0260305500001282 ◽

1986 ◽

Vol 8 ◽

pp. 124-128 ◽

Cited By ~ 14

Author(s):

N.F. McIntyre

Keyword(s):

Three Dimensional ◽

Ice Sheet ◽

Coastal Regions ◽

Three Dimensional Flow ◽

Ice Flow ◽

Antarctic Ice Sheet ◽

Dimensional Flow ◽

Ice Velocity ◽

The Antarctic ◽

Ice Sheet Topography

Mapping the topography of the Antarctic ice sheet has confirmed that there is, typically, a decrease in the wavelength and increase in the amplitude of surface undulations with distance from ice divides. This pattern is distorted by converging ice flow in coastal regions and by other variations in subglacial relief, ice velocity, and viscosity. The near-symmetry of undulations indicates the extent of three-dimensional flow over bedrock peaks. Spectral analyses indicate the greater response of the ice sheet to bedrock features with longer wavelengths. This is affected, and in some cases dominated, by the inhomogeneous and non-isothermal nature of the ice sheet.

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Multidecadal elevation changes from spy satellite images: application to glaciers and landslides

10.5194/egusphere-egu2020-9153 ◽

2020 ◽

Author(s):

Amaury Dehecq ◽

Alex Gardner ◽

Oleg Alexandrov ◽

David Shean ◽

Pascal Lacroix

Keyword(s):

Surface Deformation ◽

Anthropogenic Activities ◽

Focal Length ◽

Regional Scale ◽

Photographic Film ◽

Glacier Mass Balance ◽

Focal Length Lens ◽

Elevation Changes ◽

Camera Position ◽

The 1960S

Earth&#8217;s surface has evolved dramatically over the last 50 years as a consequence of anthropogenic activities and climate change. The observation of such changes at decadal scales is often limited to sparse in-situ observations. The growth of satellite remote-sensing has enabled such monitoring at regional/global scales but generally over less than two decades.More than 2 million images have been acquired by American reconnaissance (&#8220;spy&#8221;) satellites on photographic film from the 1960s to the 1980s, and progressively declassified. With near-global coverage and meter to sub-meter resolution, these images have a large potential for many geoscience applications. However the photographic archive represents a unique set of challenges: pre-processing of the scans, correction of the image distortion caused during storing and scanning, poorly known camera positions and parameters. The vast majority of studies using these data rely on tedious manual processing of the data, hindering regional scale applications.Here, we present the existing datasets and the development of an automated processing pipeline. We will focus in particular on images acquired by the Hexagon mapping camera (1973-1980, 12 missions) at 6-9 m ground resolution. A fully automated workflow has been developed to detect the 1081 fiducial markers present on the image, correct for distortion and stitch the different parts of the image, scanned in multiple sections. The pre-processed images are then used to generate Digital Elevation Models (DEMs) at 24 m resolution with the open-source NASA Ames Stereo Pipeline. The developed workflow is able to automatically solve for the unknown camera positions/orientations and optimally aligns the DEMs to an ancillary DEM for the determination of elevation changes. The application to ~600 images has revealed systematic biases in the retrieved elevation, up to 30 m error, linked to uncertainties in the camera parameters (focal length, lens distortion). We present a methodology to refine these parameters using an ancillary DEM only, without use of manual Ground Control Points. The KH-9 elevation is then validated against existing maps in Europe and Alaska and shows a vertical accuracy of ~5 m (68% interval) to 10-15 m (95% interval), sufficient for the study of large surface deformation (glaciers, landslides).Finally, we conclude with several use of these data for the estimation of 40 years geodetic glacier mass balance in Europe and Alaska, and irrigation-triggered landslides in South Peru.

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Antarctic Ice-Sheet Topography and Surface-Bedrock Relationships

Annals of Glaciology ◽

10.3189/s0260305500001282 ◽

1986 ◽

Vol 8 ◽

pp. 124-128 ◽

Cited By ~ 3

Author(s):

N.F. McIntyre

Keyword(s):

Three Dimensional ◽

Ice Sheet ◽

Coastal Regions ◽

Three Dimensional Flow ◽

Ice Flow ◽

Antarctic Ice Sheet ◽

Dimensional Flow ◽

Ice Velocity ◽

The Antarctic ◽

Ice Sheet Topography

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Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Nanomaterials ◽

10.3390/nano11061615 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1615

Author(s):

Qiong Li ◽

Jürgen Gluch ◽

Zhongquan Liao ◽

Juliane Posseckardt ◽

André Clausner ◽

...

Keyword(s):

Fracture Behavior ◽

Three Dimensional ◽

Mechanical Tests ◽

Fracture Force ◽

Thickness Change ◽

X Ray ◽

Transmission Electron ◽

Percentage Concentration ◽

Morphology Characterization

Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms that Ellerbeckia is different from Melosira. Both genera reveal heavily silicified frustules with valve faces linking together and forming cylindrical chains. For this cylindrical architecture of both genera, valve face thickness, mantle wall thickness and copulae thickness change with the cylindrical diameter. Furthermore, EDS reveals that these fossil frustules contain Si and O only, with no other elements in the percentage concentration range. Nanopores with a diameter of approximately 15 nm were detected inside the biosilica of both genera using TEM. In situ micromechanical experiments with uniaxial loading were carried out within the nano-XCT on these fossil frustules to determine the maximal loading force under compression and to describe the fracture behavior. The fracture force of both genera is correlated to the dimension of the fossil frustules. The results from in situ mechanical tests show that the crack initiation starts either at very thin features or at linking structures of the frustules.

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Three-dimensional deformation time series of glacier motion from multiple-aperture DInSAR observation

Journal of Geodesy ◽

10.1007/s00190-019-01325-y ◽

2019 ◽

Vol 93 (12) ◽

pp. 2651-2660 ◽

Cited By ~ 2

Author(s):

Sergey Samsonov

Keyword(s):

Time Series ◽

Surface Deformation ◽

Ground Deformation ◽

Three Dimensional ◽

Data Sets ◽

Ice Flow ◽

The North ◽

Glacier Ice ◽

Deformation Component ◽

3D Deformation

AbstractThe previously presented Multidimensional Small Baseline Subset (MSBAS-2D) technique computes two-dimensional (2D), east and vertical, ground deformation time series from two or more ascending and descending Differential Interferometric Synthetic Aperture Radar (DInSAR) data sets by assuming that the contribution of the north deformation component is negligible. DInSAR data sets can be acquired with different temporal and spatial resolutions, viewing geometries and wavelengths. The MSBAS-2D technique has previously been used for mapping deformation due to mining, urban development, carbon sequestration, permafrost aggradation and pingo growth, and volcanic activities. In the case of glacier ice flow, the north deformation component is often too large to be negligible. Historically, the surface-parallel flow (SPF) constraint was used to compute the static three-dimensional (3D) velocity field at various glaciers. A novel MSBAS-3D technique has been developed for computing 3D deformation time series where the SPF constraint is utilized. This technique is used for mapping 3D deformation at the Barnes Ice Cap, Baffin Island, Nunavut, Canada, during January–March 2015, and the MSBAS-2D and MSBAS-3D solutions are compared. The MSBAS-3D technique can be used for studying glacier ice flow at other glaciers and other surface deformation processes with large north deformation component, such as landslides. The software implementation of MSBAS-3D technique can be downloaded from http://insar.ca/.

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Energetic particle induced intra-seasonal variability of ozone inside the Antarctic polar vortex observed in satellite data

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-3327-2015 ◽

2015 ◽

Vol 15 (6) ◽

pp. 3327-3338 ◽

Cited By ~ 19

Author(s):

T. Fytterer ◽

M. G. Mlynczak ◽

H. Nieder ◽

K. Pérot ◽

M. Sinnhuber ◽

...

Keyword(s):

Geomagnetic Activity ◽

Seasonal Variability ◽

Transport Model ◽

Three Dimensional ◽

Polar Vortex ◽

Quiet Time ◽

Significance Level ◽

Antarctic Polar Vortex ◽

Ap Index ◽

The Antarctic

Abstract. Measurements from 2002 to 2011 by three independent satellite instruments, namely MIPAS, SABER, and SMR on board the ENVISAT, TIMED, and Odin satellites are used to investigate the intra-seasonal variability of stratospheric and mesospheric O3 volume mixing ratio (vmr) inside the Antarctic polar vortex due to solar and geomagnetic activity. In this study, we individually analysed the relative O3 vmr variations between maximum and minimum conditions of a number of solar and geomagnetic indices (F10.7 cm solar radio flux, Ap index, ≥ 2 MeV electron flux). The indices are 26-day averages centred at 1 April, 1 May, and 1 June while O3 is based on 26-day running means from 1 April to 1 November at altitudes from 20 to 70 km. During solar quiet time from 2005 to 2010, the composite of all three instruments reveals an apparent negative O3 signal associated to the geomagnetic activity (Ap index) around 1 April, on average reaching amplitudes between −5 and −10% of the respective O3 background. The O3 response exceeds the significance level of 95% and propagates downwards throughout the polar winter from the stratopause down to ~ 25 km. These observed results are in good qualitative agreement with the O3 vmr pattern simulated with a three-dimensional chemistry-transport model, which includes particle impact ionisation.

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Experimental Investigations of Interactions between Sand Wave Movements, Flow Structure, and Individual Aquatic Plants in Natural Rivers: A Case Study of Potamogeton Pectinatus L.

Water ◽

10.3390/w10091166 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1166 ◽

Cited By ~ 8

Author(s):

Łukasz Przyborowski ◽

Anna Łoboda ◽

Robert Bialik

Keyword(s):

Flow Velocity ◽

Three Dimensional ◽

Potamogeton Pectinatus ◽

Sand Wave ◽

Experimental Investigations ◽

Cross Sectional ◽

Bending Tests ◽

Long Duration ◽

Elevation Changes

Long-duration measurements were performed in two sandy bed rivers, and three-dimensional (3D) flow velocity and bottom elevation changes were measured in a vegetated area and in a clear region of a river. Detailed flow velocity profiles downstream and upstream of a single specimen of Potamogeton pectinatus L. were obtained and the bed morphology was assessed. Potamogeton plants gathered from each river were subjected to tensile and bending tests. The results show that the existence of the plants was influenced by both bottom and flow conditions, as the plants were located where water velocity was lower by 12% to 16% in comparison to clear region. The characteristics of the flow and sand forms depended on the cross-sectional arrangement of the river, e.g., dunes were approximately four times higher in the middle of the river than in vegetated regions near the bank. Furthermore, the studied hydrophytes were too sparse to affect water flow and had no discernible impact on the sand forms’ movements. The turbulent kinetic energy downstream of a single plant was reduced by approximately 25%. Additionally, the plants’ biomechanical characteristics and morphology were found to have adjusted to match the river conditions.

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Fuzzy B-spline for three-dimensional urban slum reconstruction from ENVISAT ASAR data

2015 10th Asian Control Conference (ASCC) ◽

10.1109/ascc.2015.7244742 ◽

2015 ◽

Author(s):

Maged Marghany

Keyword(s):

Three Dimensional ◽

Urban Slum ◽

B Spline ◽

Envisat Asar

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Recent ice-surface-elevation changes of Fleming Glacier in response to the removal of the Wordie Ice Shelf, Antarctic Peninsula

Annals of Glaciology ◽

10.3189/172756410791392727 ◽

2010 ◽

Vol 51 (55) ◽

pp. 97-102 ◽

Cited By ~ 15

Author(s):

J. Wendt ◽

A. Rivera ◽

A. Wendt ◽

F. Bown ◽

R. Zamora ◽

...

Keyword(s):

Antarctic Peninsula ◽

Regional Climate ◽

Airborne Lidar ◽

Similar Data ◽

Ice Shelf ◽

International Polar Year ◽

Ice Flow ◽

Ice Shelves ◽

Elevation Changes ◽

The Antarctic

AbstractRegional climate warming has caused several ice shelves on the Antarctic Peninsula to retreat and ultimately collapse during recent decades. Glaciers flowing into these retreating ice shelves have responded with accelerating ice flow and thinning. The Wordie Ice Shelf on the west coast of the Antarctic Peninsula was reported to have undergone a major areal reduction before 1989. Since then, this ice shelf has continued to retreat and now very little floating ice remains. Little information is currently available regarding the dynamic response of the glaciers feeding the Wordie Ice Shelf, but we describe a Chilean International Polar Year project, initiated in 2007, targeted at studying the glacier dynamics in this area and their relationship to local meteorological conditions. Various data were collected during field campaigns to Fleming Glacier in the austral summers of 2007/08 and 2008/09. In situ measurements of ice-flow velocity first made in 1974 were repeated and these confirm satellite-based assessments that velocity on the glacier has increased by 40–50% since 1974. Airborne lidar data collected in December 2008 can be compared with similar data collected in 2004 in collaboration with NASA and the Chilean Navy. This comparison indicates continued thinning of the glacier, with increasing rates of thinning downstream, with a mean of 4.1 ± 0.2 m a−1 at the grounding line of the glacier. These comparisons give little indication that the glacier is achieving a new equilibrium.

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

Remote Sensing ◽

10.3390/rs10081236 ◽

2018 ◽

Vol 10 (8) ◽

pp. 1236 ◽

Cited By ~ 1

Author(s):

Seung Hee Kim ◽

Duk-jin Kim ◽

Hyun-Cheol Kim

Keyword(s):

High Resolution ◽

Surface Deformation ◽

Surface Expression ◽

Deformation Model ◽

Ice Shelf ◽

Pressure Source ◽

Viscoelastic Deformation ◽

Shelf Stability ◽

Transient Nature ◽

Elevation Changes

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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