scholarly journals An automatic approach to delineate the cold–temperate transition surface with ground-penetrating radar on polythermal glaciers

2014 ◽  
Vol 55 (67) ◽  
pp. 89-96 ◽  
Author(s):  
Clemens Schannwell ◽  
Tavi Murray ◽  
Bernd Kulessa ◽  
Alessio Gusmeroli ◽  
Albane Saintenoy ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Thermal Structure ◽  
Gradual Transition ◽  
Signal Power ◽  
Automated Method ◽  
Automatic Picking ◽  
Transition Surface ◽  
The Difference ◽  
Ground Penetrating ◽  
Good Agreement

AbstractGround-penetrating radar has been widely used to map the thermal structure of polythermal glaciers. Hitherto, the cold–temperate transition surface (CTS) in radargrams has been identified by a labour-intensive and subjective manual picking method. We introduce a new automatic approach for picking the CTS that uses the difference in signal power exhibited by the cold and temperate ice layers. We compare our automatically computed CTS depths with manual picks. Our results show very good agreement between the two methods in most areas (r2 > 0.7). RMSEs computed at each trace in two-way travel-time from three test sites range from 14 to 19ns (2.4–3.2 m). The proposed automated method mostly fails in areas showing a rather gradual transition in signal power at the CTS. In some areas, high power originating from non-water sources is misinterpreted by the automatic picking method as ‘temperate ice’.

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

scholarly journals Reconstruction of historical surface mass balance, 1984–2017 from GreenTrACS multi-offset ground-penetrating radar

2020 ◽  
pp. 1-10
Author(s):  
Tate G. Meehan ◽  
H. P. Marshall ◽  
John H. Bradford ◽  
Robert L. Hawley ◽  
Thomas B. Overly ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Surface Mass Balance ◽  
Snow Density ◽  
Surface Mass ◽  
Age Model ◽  
Ground Penetrating ◽  
Good Agreement

Abstract We present continuous estimates of snow and firn density, layer depth and accumulation from a multi-channel, multi-offset, ground-penetrating radar traverse. Our method uses the electromagnetic velocity, estimated from waveform travel-times measured at common-midpoints between sources and receivers. Previously, common-midpoint radar experiments on ice sheets have been limited to point observations. We completed radar velocity analysis in the upper ~2 m to estimate the surface and average snow density of the Greenland Ice Sheet. We parameterized the Herron and Langway (1980) firn density and age model using the radar-derived snow density, radar-derived surface mass balance (2015–2017) and reanalysis-derived temperature data. We applied structure-oriented filtering to the radar image along constant age horizons and increased the depth at which horizons could be reliably interpreted. We reconstructed the historical instantaneous surface mass balance, which we averaged into annual and multidecadal products along a 78 km traverse for the period 1984–2017. We found good agreement between our physically constrained parameterization and a firn core collected from the dry snow accumulation zone, and gained insights into the spatial correlation of surface snow density.

scholarly journals Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by ground penetrating radar

2011 ◽  
Vol 5 (1) ◽  
pp. 139-149 ◽  
Author(s):  
K. Bælum ◽  
D. I. Benn
Keyword(s):  
Ground Penetrating Radar ◽  
Thermal Structure ◽  
Drainage System ◽  
High Arctic ◽  
Differential Gps ◽  
Glacier Surface ◽  
Digital Elevation ◽  
Drainage Channels ◽  
Ground Penetrating ◽  
Subglacial Drainage

Abstract. Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. Digital elevation models (DEMs) of the glacier surface and bed were constructed using maps, differential GPS and ground penetrating radar (GPR). Rates of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and roof closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though no signs of temperate ice were detected and the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

scholarly journals Practical Approach for High-Resolution Airport Pavement Inspection with the Yakumo Multistatic Array Ground-Penetrating Radar System

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2684 ◽  
Author(s):  
Li Yi ◽  
Lilong Zou ◽  
Motoyuki Sato
Keyword(s):  
Ground Penetrating Radar ◽  
Estimation Method ◽  
Ground Truth ◽  
Radar System ◽  
Velocity Estimation ◽  
Velocity Spectrum ◽  
Airport Pavement ◽  
Ground Penetrating ◽  
Airport Site ◽  
Good Agreement

It is important to identify the thin cracks within the airport pavement layers. To achieve this goal, a practical interferometric approach using the Yakumo multistatic ground-penetrating radar system was developed to detect the slight variability in wave propagation velocity and/or thickness caused by the thin cracks. In comparison with the conventional common midpoint (CMP) velocity estimation method, the proposed method can provide much higher-resolution estimations of slight deviations in the velocity and thickness from their corresponding reference values in the undamaged asphalt through the comparison of two CMP datasets. These deviations can be obtained analytically instead of graphically extracted from the CMP velocity spectrum. The proposed approach was not only analyzed using the simulated datasets, but also practically demonstrated at both an experimental model site and an actual airport site. In the simulation tests, velocity deviations on the order of a few millimeters per nanosecond were detected, and the experimental results shows good agreement with the ground truth and coring samples. This method provides a novel way to inspect partially damaged pavement when the thin cracks are difficult to detect using the reflected signals.

scholarly journals Interpretation Of Ground Penetrating Radar Attributes In Identifying The Risk Of Mining Subsidence

2015 ◽  
Vol 60 (2) ◽  
pp. 645-656 ◽  
Author(s):  
Sylwia Tomecka-Suchoń ◽  
Henryk Marcak
Keyword(s):  
Ground Penetrating Radar ◽  
Amplitude Envelope ◽  
Instantaneous Amplitude ◽  
Geophysical Surveys ◽  
Mechanisms Of Formation ◽  
Transport Safety ◽  
Recorded Data ◽  
Mine Workings ◽  
The Difference ◽  
Ground Penetrating

Abstract Sinkholes which occur in regions of old mine workings increase the risk to building and transport safety. Geophysical surveys, particularly with the use of ground penetrating radar (GPR), can help to locate underground voids which migrate towards the surface before they transform into sinkholes. The mining region in Upper Silesia, Poland was selected to test the method. The test was carried out on the profile at which sinkhole appeared few months after measurements. It can be assumed that the development of deformations in the ground was preceded by hydraulic and geomechanical processes, which directly caused this event. To identify the cause of the sinkhole formation exactly in this place in which it is located we carried out interpretation of GPR measurements through the calculation of GPR signals attributes such as instantaneous phase, instantaneous amplitude envelope, envelope derivative, envelope second derivative. The difference between two similar recorded data can be interpreted as a result of existence of hydraulic channels. On reflection, it appears that GPR signals attributes can be an important tool not only in the location of a cavity voids, but also can help in understanding the mechanisms of formation of the sinkholes.

scholarly journals On measuring snow ablation rates in alpine terrain with a mobile GPR device

2017 ◽  
Author(s):  
Nena Griessinger ◽  
Franziska Mohr ◽  
Tobias Jonas
Keyword(s):  
Ground Penetrating Radar ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Winter Season ◽  
Repeated Measurements ◽  
Swiss Alps ◽  
Promising Technique ◽  
Snow Water ◽  
Ground Penetrating ◽  
Good Agreement

Abstract. Ground penetrating radar (GPR) has become a promising technique in the field of snow hydrological research. It is commonly used to measure snow depth, density, and water equivalent over large distances or along gridded snow courses. Having built and tested a mobile light-weight setup, we demonstrate that GPR is capable of accurately measuring snow ablation rates in complex alpine terrain. Our setup was optimized for efficient measurements and consisted of a common-mid-point assembly with four pairs of antennas mounted to a plastic sled, which was small enough to permit safe and convenient operations. Repeated measurements were taken during the 2014/15 winter season along ten profiles within two valleys located in the eastern Swiss Alps. Resulting GPR-based data of snow depth and water equivalent as well as their respective change rates over time were in good agreement with concurrent manual measurements, in particular if accurate alignment between repeated overpasses could be achieved (root-mean-square error of 4.5 cm for snow depth, 25 mm for snow water equivalent, and 4.4 cm and 26 mm for the respective change rates). With its suitability for alpine terrain and the achieved accuracy, the presented setup could become a valuable tool to validate snowmelt models or to complement lidar-based snow surveys.

scholarly journals Automated method for buried object detecting using ground penetrating radar (GPR) survey

2019 ◽  
Vol 12 (23) ◽  
pp. 80-89
Author(s):  
Israa J. Muhsin
Keyword(s):  
Image Processing ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Short Pulse ◽  
Radio Spectrum ◽  
Buried Objects ◽  
Automated Method ◽  
Buried Object ◽  
Geophysical Technique ◽  
Ground Penetrating

  Ground Penetrating Radar (GPR) is a nondestructive geophysical technique that uses electromagnetic waves to evaluate subsurface information. A GPR unit emits a short pulse of electromagnetic energy and is able to determine the presence or absence of a target by examining the reflected energy from that pulse. GPR is geophysical approach that use band of the radio spectrum. In this research the function of GPR has been summarized as survey different buried objects such as (Iron, Plastic(PVC), Aluminum) in specified depth about (0.5m) using antenna of 250 MHZ, the response of the each object can be recognized as its shapes, this recognition have been performed using image processing such as filtering. Where different filters like (DC adjustment, triangular FIR, delete mean trace, FIR) have been applied on output image as well as the simulation of the soil and the buried objects layers have been obtained using GPR simulation program.

Cold–temperate transition surface and permafrost base (CTS-PB) as an environmental axis in glacier–permafrost relationship, based on research carried out on the Storglaciären and its forefield, northern Sweden

2017 ◽  
Vol 88 (3) ◽  
pp. 551-569 ◽  
Author(s):  
Wojciech Dobiński ◽  
Mariusz Grabiec ◽  
Michał Glazer
Keyword(s):  
Ground Penetrating Radar ◽  
Cold Climate ◽  
Northern Sweden ◽  
Climatic Fluctuation ◽  
Glacial Ice ◽  
Empirical Ground ◽  
Glacial Environments ◽  
Transition Surface ◽  
Ground Penetrating ◽  
Tomography Data

AbstractHere, we present empirical ground penetrating radar (GPR) and electroresistivity tomography data (ERT) to verify the cold-temperate transition surface-permafrost base (CTS-PB) axis theoretical model. The data were collected from Storglaciären, in Tarfala, Northern Sweden, and its forefield. The GPR results show a material relation between the glacial ice and the sediments incorporated in the glacier, and a geophysical relation between the “cold ice” and the “temperate ice” layers. Clearly identifying lateral glacier margins is difficult, as periglacial and glacial environments frequently overlap. In this case, we identified areas showing permafrost aggradation already under the glacier, particularly where the CTS is replaced by the PB surface. This structure appears as a result of the influence of a cold climate over both the glacial and periglacial environments. The results show how these surfaces form a specific continuous environmental axis; thus, both glacial and periglacial areas can be treated uniformly as a specific continuum in the geophysical sense. Similarly, other examples previously described also allow identifying a continuation of permafrost from the periglacial environment onto the glacial base. In addition, the ERT results show the presence of double-layered periglacial permafrost, possibly suggesting a past climatic fluctuation in the study area.

Ground-penetrating radar refraction imaging with stacked refraction convolution section method

Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. H33-H45 ◽  
Author(s):  
Roberto de Franco ◽  
Grazia Caielli ◽  
Alberto Villa ◽  
Federico Agliardi ◽  
Francesco Franchino
Keyword(s):  
Ground Penetrating Radar ◽  
Seismic Refraction ◽  
Common Source ◽  
Data Set ◽  
Near Surface ◽  
Processing Times ◽  
Full Wave ◽  
Ground Penetrating ◽  
Refraction Data ◽  
Good Agreement

We have evaluated a technique initially developed for the seismic refraction imaging, the stacked refraction convolution section (SRCS), which we have properly adapted to process ground-penetrating radar (GPR) refraction data. Through a mute operation, the subsurface refracting signals, recorded by the receiver from two reciprocal sources, are selected. Following that, a velocity analysis by means of the crosscorrelation of the refracted signals and the convolution of resulting traces is performed. The refraction image in intercept times is successively derived from three main steps, namely: (1) the convolution of the subsurface refracted signals, (2) the crosscorrelation of convolved trace with the reciprocal refracted signal, and (3) the stacking of crosscorrelated traces over all source couples. The technique is not only suitable for the processing of GPR data acquired with two or more reciprocal common source profiles but it is also convenient for its low acquisition cost in addition to the simplicity of software implementation and short processing times. We have evaluated the technique on a real GPR data set to characterize a near-surface morphostructure associated with a deep-seated gravitational slope deformation affecting Mt. Watles (Upper Venosta Valley, Italy). Results of the SRCS technique were validated against the direct trenching log data up to approximately 3 m in depth and complemented by the reflection processing outputs of common-source and common-offset data acquired along the line. The SRCS and common-midpoint processing provide the best reconstruction of the subsurface morphology of a shallow basement (approximately [Formula: see text] depth), characterized by a velocity range of [Formula: see text] and made of strongly to moderately weathered paragneiss. The full-wave modeling response of the reconstructed model demonstrates good agreement with the recorded signals.

scholarly journals Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by Ground Penetrating Radar

2010 ◽  
Vol 4 (4) ◽  
pp. 2169-2199
Author(s):  
K. Bælum ◽  
D. I. Benn
Keyword(s):  
Ground Penetrating Radar ◽  
Thermal Structure ◽  
Drainage System ◽  
High Arctic ◽  
Differential Gps ◽  
Glacier Surface ◽  
Drainage Channels ◽  
Polythermal Glacier ◽  
Ground Penetrating ◽  
Subglacial Drainage

Abstract. Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long cold-based polythermal glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. DEMs of the glacier surface and bed were constructed using maps, differential GPS and GPR. Patterns of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using Ground penetrating radar (GPR), showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

Sign in / Sign up

Export Citation Format

Share Document