scholarly journals Magnetometry and ground penetrating radar in application to mapping of polygonal wedge ice of yedoma complex

2018 ◽  
Vol 64 (4) ◽  
pp. 427-438
Author(s):  
L. V. Tsibizov ◽  
E. I. Esin ◽  
A. V. Grigorevskaya ◽  
K. A. Sosnovtsev
Keyword(s):  
Magnetic Field ◽  
Ground Penetrating Radar ◽  
Radar Data ◽  
Magnetic Survey ◽  
Lena River ◽  
Digital Elevation ◽  
Polygonal Pattern ◽  
Elevation Model ◽  
Ground Penetrating ◽  
Ice Complex

Paper is dedicated to geophysical mapping of polygonal wedge ice. Magnetometric and ground penetrating radar surveys were implemented on a small area of Yedoma ice complex on Kurungnakh island in Lena river delta. Such deposits are widely spread on a huge areas of Siberia and Alaska. The study was conducted near the thermoerosional gully, which propagates along the most thick ice wedges. Polygonal pattern is observable on high-resolution aerial imagery and digital elevation model - this data was used during the interpreting of obtained results. Study area (40×50 m) was covered with highresolution magnetic survey at the elevation of 2 m with 2×2 m step and with ground penetrating radar survey along profiles with 1 m distance between the profiles. Map of total magnetic field anomalies allow to determine the ice wedges of Yedoma ice complex distinctly. Difference between maximum positive (polygons centers) and negative (ice wedges) anomalies reaches 6 nT (error of the survey is 0,3 nT). Beyond that smaller ice wedges which penetrate the ice wedges of Yedoma complex are also observable in magnetic field. Basing on ground penetrating radar data an amplitude slice of at 3,5 m depth was built. Yedoma ice wedges are observable at depth of 3–4 m. Ground penetrating radar data is quite noisy due to surface inhomogeneity (puddles, knolls, etc.). Results of the surveys were compared in the light of practical application of the methods for above mentioned goal. Magnetometric method appears as more efficient than ground penetrating radar survey: it does not require a contact with the surface and more rapid, it is more sensitive as the case stands. Ground penetrating radar method may have advantages in the case of natural (magnetic storm, high-magnetized overlaying deposits) and anthropogenic (metal constructions — pipelines, ETL) noise.

scholarly journals Ground-penetrating radar reveals ice thickness and undisturbed englacial layers at Kilimanjaro's Northern Ice Field

2016 ◽  
Author(s):  
Pascal Bohleber ◽  
Leo Sold ◽  
Douglas R. Hardy ◽  
Margit Schwikowski ◽  
Patrick Klenk ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Ice Core ◽  
Sampling Site ◽  
Vertical Wall ◽  
Ice Thickness ◽  
Depth Information ◽  
Digital Elevation ◽  
Ice Field ◽  
Elevation Model ◽  
Ground Penetrating

Abstract. Although its Holocene glacier history is still subject to debate, the ongoing iconic decline of Kilimanjaro's largest remaining ice body, the Northern Ice Field (NIF), has been documented extensively based on surface and photogrammetric measurements. The study presented here adds, for the first time, ground-penetrating radar (GPR) data at center frequencies of 100 and 200 MHz to investigate bedrock topography, ice thickness and internal stratigraphy at NIF. The direct comparison of the GPR signal to the visible glacier stratigraphy at NIF's vertical walls is used to validate ice thickness and reveals that the major internal reflections seen by GPR can be associated with dust layers. Englacial reflections can be traced consistently within our 200 MHz profiles, indicating an undisturbed internal stratigraphy within NIF's central flat area. We show that it is possible to follow isochrone layers between two former NIF ice core drilling sites and a sampling site on NIF's vertical wall. As a result, these isochrone layers provide constraints for future attempts at linking age-depth information obtained from multiple locations at NIF. The GPR profiles reveal an ice thickness ranging between (6.1 ± 0.5) and (53.5 ± 1.0) m. Combining these data with a very high resolution digital elevation model we spatially extrapolate ice thickness and give an estimate of the total ice volume remaining at NIF's southern portion as (12.0 ± 0.3) 106 m3.

scholarly journals Post−surge geometry and thermal structure of Hørbyebreen, central Spitsbergen

2013 ◽  
Vol 34 (3) ◽  
pp. 305-321 ◽  
Author(s):  
Jakub Małecki ◽  
Samuel Faucherre ◽  
Mateusz C. Strzelecki
Keyword(s):  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Considerable Increase ◽  
Thermal Structure ◽  
Radar Data ◽  
Negative Mass ◽  
Contour Lines ◽  
Digital Elevation ◽  
Geodetic Mass Balance ◽  
Ground Penetrating

Abstract Hørbyebreen surged in the 19th or early 20th century, as suggested by geomorphological evidences and looped medial moraines. In this study, we investigate its wide−spread geometry changes and geodetic mass balance with 1960 contour lines, 1990 and 2009 digital elevation models, in order to define the present−day state of the glacier. We also study its thermal structure from ground−penetrating radar data. Little is known about the glacier behaviour in the first part of the 20th century, but from its surge maximum until 1960 it has been retreating and losing its area. In the period 1960-1990, fast frontal thinning (2-3ma−1) and a slow mass build−up in the higher zones (~0.15 m a−1) have been noted, resulting in generally negative mass balance (−0.40 ± 0.07 m w. eq. a−1). In the last studied period 1990-2009, the glacier showed an acceleration of mass loss (−0.64 m ± 0.07 w. eq. a−1) and no build−up was observed anymore. We conclude that Hørbyebreen system under present climate will not surge anymore and relate this behaviour to a considerable increase in summer temperature on Svalbard after 1990. Radar soundings indicate that the studied glacial system is polythermal, with temperate ice below 100-130 m depth. It has therefore not (or not yet) switched to cold−bedded, as has been suggested in previous works for some small Svalbard surge−type glaciers in a negative mass balance mode.

scholarly journals Ground-penetrating radar reveals ice thickness and undisturbed englacial layers at Kilimanjaro's Northern Ice Field

2017 ◽  
Vol 11 (1) ◽  
pp. 469-482 ◽  
Author(s):  
Pascal Bohleber ◽  
Leo Sold ◽  
Douglas R. Hardy ◽  
Margit Schwikowski ◽  
Patrick Klenk ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Ice Core ◽  
Sampling Site ◽  
Vertical Wall ◽  
Ice Thickness ◽  
Depth Information ◽  
Digital Elevation ◽  
Ice Field ◽  
Elevation Model ◽  
Ground Penetrating

Abstract. Although its Holocene glacier history is still subject to debate, the ongoing iconic decline of Kilimanjaro's largest remaining ice body, the Northern Ice Field (NIF), has been documented extensively based on surface and photogrammetric measurements. The study presented here adds, for the first time, ground-penetrating radar (GPR) data at centre frequencies of 100 and 200 MHz to investigate bed topography, ice thickness and internal stratigraphy at NIF. The direct comparison of the GPR signal to the visible glacier stratigraphy at NIF's vertical walls is used to validate ice thickness and reveals that the major internal reflections seen by GPR can be associated with dust layers. Internal reflections can be traced consistently within our 200 MHz profiles, indicating an uninterrupted, spatially coherent internal layering within NIF's central flat area. We show that, at least for the upper 30 m, it is possible to follow isochrone layers between two former NIF ice core drilling sites and a sampling site on NIF's vertical wall. As a result, these isochrone layers provide constraints for future attempts at linking age–depth information obtained from multiple locations at NIF. The GPR profiles reveal an ice thickness ranging between (6.1 ± 0.5) and (53.5 ± 1.0) m. Combining these data with a very high resolution digital elevation model we spatially extrapolate ice thickness and give an estimate of the total ice volume remaining at NIF's southern portion as (12.0 ± 0.3) × 106 m3.

Reconstructing Properties of Subsurface from Ground-Penetrating Radar Data

PIERS Online ◽  
2006 ◽  
Vol 2 (6) ◽  
pp. 567-572
Author(s):  
Hui Zhou ◽  
Dongling Qiu ◽  
Takashi Takenaka
Keyword(s):  
Ground Penetrating Radar ◽  
Radar Data ◽  
Ground Penetrating

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.

scholarly journals Ground penetrating radar data used in discovery of the early Christian church of Notre Dame de Baudes near Labastide-du-Temple, France

Data in Brief ◽  
2016 ◽  
Vol 7 ◽  
pp. 1588-1593 ◽  
Author(s):  
Ted L Gragson ◽  
Victor D. Thompson ◽  
David S. Leigh ◽  
Florent Hautefeuille
Keyword(s):  
Ground Penetrating Radar ◽  
Radar Data ◽  
Christian Church ◽  
Early Christian ◽  
Ground Penetrating
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