scholarly journals Ice volume and basal topography estimation using geostatistical methods and ground-penetrating radar measurements: application to the Tsanfleuron and Scex Rouge glaciers, Swiss Alps

2021 ◽  
Vol 15 (11) ◽  
pp. 5169-5186
Author(s):  
Alexis Neven ◽  
Valentin Dall'Alba ◽  
Przemysław Juda ◽  
Julien Straubhaar ◽  
Philippe Renard
Keyword(s):  
Ground Penetrating Radar ◽  
Volume Estimation ◽  
Swiss Alps ◽  
Data Set ◽  
Mountain Glacier ◽  
Ice Volume ◽  
Bedrock Topography ◽  
Direct Sampling ◽  
Ground Penetrating ◽  
Geomorphological Features

Abstract. Ground-penetrating radar (GPR) is widely used for determining mountain glacier thickness. However, this method provides thickness data only along the acquisition lines, and therefore interpolation has to be made between them. Depending on the interpolation strategy, calculated ice volumes can differ and can lack an accurate error estimation. Furthermore, glacial basal topography is often characterized by complex geomorphological features, which can be hard to reproduce using classical interpolation methods, especially when the field data are sparse or when the morphological features are too complex. This study investigates the applicability of multiple-point statistics (MPS) simulations to interpolate glacier bedrock topography using GPR measurements. In 2018, a dense GPR data set was acquired on the Tsanfleuron Glacier (Switzerland). These data were used as the source for a bedrock interpolation. The results obtained with the direct-sampling MPS method are compared against those obtained with kriging and sequential Gaussian simulations (SGSs) on both a synthetic data set – with known reference volume and bedrock topography – and the real data underlying the Tsanfleuron Glacier. Using the MPS modeled bedrock, the ice volume for the Scex Rouge and Tsanfleuron glaciers is estimated to be 113.9 ± 1.6 million cubic meters. The direct-sampling approach, unlike the SGS and kriging, allowed not only an accurate volume estimation but also the generation of a set of realistic bedrock simulations. The complex karstic geomorphological features are reproduced and can be used to significantly improve for example the precision of subglacial flow estimation.

scholarly journals Ice volume and basal topography estimation using geostatistical methods and GPR measurements : Application on the Tsanfleuron and Scex Rouge glacier, Swiss Alps

2021 ◽  
Author(s):  
Alexis Neven ◽  
Valentin Dall'Alba ◽  
Przemysław Juda ◽  
Julien Straubhaar ◽  
Philippe Renard
Keyword(s):  
Synthetic Data ◽  
Real Data ◽  
Volume Estimation ◽  
Swiss Alps ◽  
Multiple Point ◽  
Data Set ◽  
Ice Volume ◽  
Bedrock Topography ◽  
Direct Sampling ◽  
Geomorphological Features

Abstract. Ground Penetrating Radar (GPR) is nowadays widely used for determining glacier thickness. However, this method provides thickness data only along the acquisition lines and therefore interpolation has to be made between them. Depending on the interpolation strategy, calculated ice volumes can differ and can lack an accurate error estimation. Furthermore, glacial basal topography is often characterized by complex geomorphological features, which can be hard to reproduce using classical interpolation methods, especially when the conditioning data are sparse or when the morphological features are too complex. This study investigates the applicability of multiple-point statistics (MPS) simulations to interpolate glacier bedrock topography using GPR measurements. In 2018, a dense GPR data set was acquired on the Tsanfleuron Glacier (Switzerland). The results obtained with the direct sampling MPS method are compared against those obtained with kriging and sequential Gaussian simulations (SGS) on both a synthetic data set – with known reference volume and bedrock topography – and the real data underlying the Tsanfleuron glacier. Using the MPS modelled bedrock, the ice volume for the Scex Rouge and Tsanfleuron Glacier is estimated to be 113.9 ± 1.6 Mio m3. The direct sampling approach, unlike the SGS and the kriging, allowed not only an accurate volume estimation but also the generation of a set of realistic bedrock simulations. The complex karstic geomorphological features are reproduced, and can be used to significantly improve for example the precision of under-glacial flow estimation.

scholarly journals Ice thickness distribution of all Swiss glaciers based on extended ground-penetrating radar data and glaciological modeling

2021 ◽  
pp. 1-19
Author(s):  
Melchior Grab ◽  
Enrico Mattea ◽  
Andreas Bauder ◽  
Matthias Huss ◽  
Lasse Rabenstein ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Thickness Distribution ◽  
Radar Data ◽  
Tourism Industry ◽  
Swiss Alps ◽  
Ice Thickness ◽  
Hazard Management ◽  
Bed Topography ◽  
Ice Volume ◽  
Ground Penetrating

Abstract Accurate knowledge of the ice thickness distribution and glacier bed topography is essential for predicting dynamic glacier changes and the future developments of downstream hydrology, which are impacting the energy sector, tourism industry and natural hazard management. Using AIR-ETH, a new helicopter-borne ground-penetrating radar (GPR) platform, we measured the ice thickness of all large and most medium-sized glaciers in the Swiss Alps during the years 2016–20. Most of these had either never or only partially been surveyed before. With this new dataset, 251 glaciers – making up 81% of the glacierized area – are now covered by GPR surveys. For obtaining a comprehensive estimate of the overall glacier ice volume, ice thickness distribution and glacier bed topography, we combined this large amount of data with two independent modeling algorithms. This resulted in new maps of the glacier bed topography with unprecedented accuracy. The total glacier volume in the Swiss Alps was determined to be 58.7 ± 2.5 km3 in the year 2016. By projecting these results based on mass-balance data, we estimated a total ice volume of 52.9 ± 2.7 km3 for the year 2020. Data and modeling results are accessible in the form of the SwissGlacierThickness-R2020 data package.

Assessing the influence of bedrock discontinuities on glacier fractures using ground-penetrating radar and structure from motion

2021 ◽  
Author(s):  
Niccolò Dematteis ◽  
Fabrizio Trolio ◽  
Daniele Giordan
Keyword(s):  
Structure From Motion ◽  
Ground Penetrating Radar ◽  
Digital Terrain Model ◽  
Volume Estimation ◽  
Strong Impact ◽  
Alpine Glacier ◽  
Terrain Model ◽  
Bedrock Topography ◽  
Related Risk ◽  
Ground Penetrating

<p>The Planpincieux Glacier lies in the Italian side of the Grandes Jorasses massif (Mont Blanc area), toward the Ferret Valley, in the Courmayeur municipality. This is a highly touristic area, visited every year by tens of thousands of people.</p><p>In summers 2019 and 2020, large portions of the Montitaz Lobe of the glacier (estimated volumes of 250000 m<sup>3</sup> and 500000 m<sup>3</sup> respectively) became unstable and menaced the Planpincieux village. According to runout simulations, such volumes could have reached and damaged a small bridge, buildings or the main valley road, depending on the volume involved in the collapse. Therefore, robust volume estimation was required for the realisation of effective safety plans.</p><p>To this aim, a helicopter-borne ground-penetrating-radar (GPR) survey was conducted in July 2020 with the novel dual polarization AIRETH system. Such a survey provided the ice thickness (20-60 ±10 m) of the unstable portion  and the bedrock topography along transects.</p><p>Besides, multiple helicopter and drone photogrammetric surveys were acquired since 2017, which provided the digital terrain model (DTM) and the orthophotos of the glacier using structure from motion (SfM) technique.</p><p>Merging GPR and SfM allowed at reconstructing the evolution of the glacier shrinkage in the period where DTMs were available. Moreover, it was possible to assess the correspondence of several bedrock discontinuities with large recurrent fractures.</p><p>Even though it is commonly acknowledged that the bedrock topography influences the glacier morphology, their correspondence has been rarely demonstrated in an Alpine glacier.</p><p>Since the fractures provoked by the bedrock discontinuities might destabilise the underlying glacier portion, the knowledge of the actual position of such fractures can help in the quantitative evaluation of the glacier instability. This can have a strong impact in the potential glacier-related risk assessment and management.</p>

Helicopter-borne ground-penetrating radar investigations on temperate alpine glaciers: A comparison of different systems and their abilities for bedrock mapping

Geophysics ◽  
2016 ◽  
Vol 81 (1) ◽  
pp. WA119-WA129 ◽  
Author(s):  
Anja Rutishauser ◽  
Hansruedi Maurer ◽  
Andreas Bauder
Keyword(s):  
Ground Penetrating Radar ◽  
Low Frequency ◽  
Large Data ◽  
Internal Reflection ◽  
Swiss Alps ◽  
Reflection Band ◽  
Data Set ◽  
Investigation Area ◽  
Attractive Option ◽  
Ground Penetrating

On the basis of a large data set, comprising approximately 1200 km of profile lines acquired with different helicopter-borne ground-penetrating radar (GPR) systems over temperate glaciers in the western Swiss Alps, we have analyzed the possibilities and limitations of using helicopter-borne GPR surveying to map the ice-bedrock interface. We have considered data from three different acquisition systems including (1) a low-frequency pulsed system hanging below the helicopter (BGR), (2) a stepped frequency system hanging below the helicopter (Radar Systemtechnik GmbH [RST]), and (3) a commercial system mounted directly on the helicopter skids (Geophysical Survey Systems Incorporated [GSSI]). The systems showed considerable differences in their performance. The best results were achieved with the BGR system. On average, the RST and GSSI systems yielded comparable results, but we observed significant site-specific differences. A comparison with ground-based GPR data found that the quality of helicopter-borne data is inferior, but the compelling advantages of airborne surveying still make helicopter-borne data acquisition an attractive option. Statistical analyses concerning the bedrock detectability revealed not only large differences between the different acquisition systems but also between different regions within our investigation area. The percentage of bedrock reflections identified (with respect to the overall profile length within a particular region) varied from 11.7% to 68.9%. Obvious factors for missing the bedrock reflections included large bedrock depths and steeply dipping bedrock interfaces, but we also observed that internal features within the ice body may obscure bedrock reflections. In particular, we identified a conspicuous “internal reflection band” in many profiles acquired with the GSSI system. We attribute this feature to abrupt changes of the water content within the ice, but more research is required for a better understanding of the nature of this internal reflection band.

scholarly journals Melt regimes, stratigraphy, flow dynamics and glaciochemistry of three glaciers in the Alaska Range

2012 ◽  
Vol 58 (207) ◽  
pp. 99-109 ◽  
Author(s):  
Seth Campbell ◽  
Karl Kreutz ◽  
Erich Osterberg ◽  
Steven Arcone ◽  
Cameron Wake ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Ice Core ◽  
Chemical Diffusion ◽  
Flow Dynamics ◽  
Alaska Range ◽  
Ice Volume ◽  
Glacier Ice ◽  
Age Model ◽  
Ground Penetrating ◽  
Climate Studies

AbstractWe used ground-penetrating radar (GPR), GPS and glaciochemistry to evaluate melt regimes and ice depths, important variables for mass-balance and ice-volume studies, of Upper Yentna Glacier, Upper Kahiltna Glacier and the Mount Hunter ice divide, Alaska. We show the wet, percolation and dry snow zones located below ~2700ma.s.l., at ~2700 to 3900ma.s.l. and above 3900ma.s.l., respectively. We successfully imaged glacier ice depths upwards of 480 m using 40-100 MHz GPR frequencies. This depth is nearly double previous depth measurements reached using mid-frequency GPR systems on temperate glaciers. Few Holocene-length climate records are available in Alaska, hence we also assess stratigraphy and flow dynamics at each study site as a potential ice-core location. Ice layers in shallow firn cores and attenuated glaciochemical signals or lacking strata in GPR profiles collected on Upper Yentna Glacier suggest that regions below 2800ma.s.l. are inappropriate for paleoclimate studies because of chemical diffusion, through melt. Flow complexities on Kahiltna Glacier preclude ice-core climate studies. Minimal signs of melt or deformation, and depth-age model estimates suggesting ~4815 years of ice on the Mount Hunter ice divide (3912ma.s.l.) make it a suitable Holocene-age ice-core location.

scholarly journals On the errors involved in ice-thickness estimates I: ground-penetrating radar measurement errors

2016 ◽  
Vol 62 (236) ◽  
pp. 1008-1020 ◽  
Author(s):  
J.J. LAPAZARAN ◽  
J. OTERO ◽  
A. MARTÍN-ESPAÑOL ◽  
F.J. NAVARRO
Keyword(s):  
Ground Penetrating Radar ◽  
Measurement Errors ◽  
Ice Thickness ◽  
Independent Components ◽  
Ice Volume ◽  
Thickness Error ◽  
Grid Points ◽  
Ground Penetrating ◽  
Volume Estimates

ABSTRACTThis is the first (Paper I) of three companion papers focused respectively, on the estimates of the errors in ice thickness retrieved from pulsed ground-penetrating radar (GPR) data, on how to estimate the errors at the grid points of an ice-thickness DEM, and on how the latter errors, plus the boundary delineation errors, affect the ice-volume estimates. We here present a comprehensive analysis of the various errors involved in the computation of ice thickness from pulsed GPR data, assuming they have been properly migrated. We split the ice-thickness error into independent components that can be estimated separately. We consider, among others, the effects of the errors in radio-wave velocity and timing. A novel aspect is the estimate of the error in thickness due to the uncertainty in horizontal positioning of the GPR measurements, based on the local thickness gradient. Another novel contribution is the estimate of the horizontal positioning error of the GPR measurements due to the velocity of the GPR system while profiling, and the periods of GPS refreshing and GPR triggering. Their effects are particularly important for airborne profiling. We illustrate our methodology through a case study of Werenskioldbreen, Svalbard.

scholarly journals Particle Center Supported Plane for Subsurface Target Classification based on Full Polarimetric Ground Penetrating Radar

2019 ◽  
Vol 11 (4) ◽  
pp. 405
Author(s):  
Xuan Feng ◽  
Haoqiu Zhou ◽  
Cai Liu ◽  
Yan Zhang ◽  
Wenjing Liang ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Decomposition Methods ◽  
Support Vector ◽  
Classification Methods ◽  
Target Classification ◽  
Data Set ◽  
Particle Center ◽  
Ground Penetrating ◽  
New Criterion

The subsurface target classification of ground penetrating radar (GPR) is a popular topic in the field of geophysics. Among the existing classification methods, geometrical features and polarimetric attributes of targets are primarily used. As polarimetric attributes contain more information of targets, polarimetric decomposition methods, such as H-Alpha decomposition, have been developed for target classification of GPR in recent years. However, the classification template used in H-Alpha classification is preset depending on the experience of synthetic aperture radar (SAR); therefore, it may not be suitable for GPR. Moreover, many existing classification methods require excessive human operation, particularly when outliers exist in the sample (the data set containing the features of targets); therefore, they are not efficient or intelligent. We herein propose a new machine learning method based on sample centers, i.e., particle center supported plane (PCSP). The sample center is defined as the point with the smallest sum of distances from all points in the same sample, which is considered as a better representation of the sample without significant effect of the outliers. In this proposed method, particle swarm optimization (PSO) is performed to obtain the sample centers; the new criterion for subsurface target classification is achieved. We applied this algorithm to full polarimetric GPR data measured in the laboratory and outdoors. The results indicate that, comparing with support vector machine (SVM) and classical H-Alpha classification, this new method is more efficient and the accuracy is relatively high.

scholarly journals Ice volume changes (1936–1990–2007) and ground-penetrating radar studies of Ariebreen, Hornsund, Spitsbergen

2013 ◽  
Vol 32 (1) ◽  
pp. 11068 ◽  
Author(s):  
Javier Lapazaran ◽  
Michal Petlicki ◽  
Francisco Navarro ◽  
Francisco Machío ◽  
Darek Puczko ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Volume Changes ◽  
Ice Volume ◽  
Ground Penetrating

On the use of dispersive APVO GPR curves for thin-bed properties estimation: Theory and application to fracture characterization

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. J1-J12 ◽  
Author(s):  
Jacques Deparis ◽  
Stéphane Garambois
Keyword(s):  
Ground Penetrating Radar ◽  
Inverse Method ◽  
Phase Variation ◽  
Fractured Media ◽  
Data Set ◽  
Fracture Characterization ◽  
Propagation Effects ◽  
Phase Liquid ◽  
Ground Penetrating ◽  
Homogeneous Formation

The presence of a thin layer embedded in any formation creates complex reflection patterns caused by interferences within the thin bed. The generated reflectivity amplitude variations with offset have been increasingly used in seismic interpretation and more recently tested on ground-penetrating radar (GPR) data to characterize nonaqueous-phase liquid contaminants. Phase and frequency sensitivities of the reflected signals are generally not used, although they contain useful information. The present study aims to evaluate the potential of these combined properties to characterize a thin bed using GPR data acquired along a common-midpoint (CMP) survey, carried out to assess velocity variations in the ground. It has been restricted to the simple case of a thin bed embedded within a homogeneous formation, a situation often encountered in fractured media. Dispersive properties ofthe dielectric permittivity of investigated materials (homogeneous formation, thin bed) are described using a Jonscher parameterization, which permitted study of the dependency of amplitude and phase variation with offset (APVO) curves on frequency and thin-bed properties (filling nature, aperture). In the second part, we discuss and illustrate the validity of the thin-bed approximation as well as simplify assumptions and make necessary careful corrections to convert raw CMP data into dispersive APVO curves. Two different strategies are discussed to correct the data from propagation effects: a classical normal-moveout approach and an inverse method. Finally, the proposed methodology is applied to a CMP GPR data set acquired along a vertical cliff. It allowed us to extract the characteristics of a subvertical fracture with satisfying resolution and confidence. The study motivates interest to use dispersion dependency of the reflection coefficient variations for thin-bed characterization.

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