Long-term mass-balance monitoring and evolution of ice in caves through structure from motion–multi-view stereo and ground-penetrating radar techniques

This study investigates the application of a terrestrial structure from motionmulti-view stereo (SfM-MVS) approach combined with ground-penetrating radar (GPR) surveys for monitoring the surface topographic change of two permanent ice deposits in caves located in the Julian Alps (south-eastern European Alps). This method allows accurate calculation of both seasonal and annual mass balance, estimating the amount of ice inside caves. The ground-based SfM approach represents a low-cost workflow with very limited logistical problems of transportation and human resources and a fast acquisition time, all key factors in such extreme environments. Under optimal conditions, SfM-MVS allows sub-centimetric resolution results, comparable to more expensive and logistically demanding surveys such as terrestrial laser scanning (TLS). Fourteen SfM acquisitions were made between the 2017–2020 ablation seasons (i.e. July–October) while 2 GPR surveys were acquired in 2012. The obtained dense point clouds and digital terrain models (DTMs) made possible a reliable calculation of topographic changes and mass balance rates during the analysed period. The integration of SfM-MVS products with GPR surveys provided comprehensive imaging of the ice thickness and the total ice volume present in each of the caves, proving to be a reliable, low cost and multipurpose methodology ideal for long-term monitoring.

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Fusion of ground penetrating radar and laser scanning for infrastructure mapping

Journal of Applied Geodesy ◽

10.1515/jag-2020-0004 ◽

2021 ◽

Vol 15 (1) ◽

pp. 31-45

Author(s):

Dominik Merkle ◽

Carsten Frey ◽

Alexander Reiterer

Keyword(s):

Ground Penetrating Radar ◽

Laser Scanning ◽

Point Clouds ◽

Soil Conditions ◽

Positioning Systems ◽

Subsurface Structures ◽

Wall Structures ◽

Surface Data ◽

Laser Scanners ◽

Ground Penetrating

AbstractMobile mapping vehicles, equipped with cameras, laser scanners (in this paper referred to as light detection and ranging, LiDAR), and positioning systems are limited to acquiring surface data. However, in this paper, a method to fuse both LiDAR and 3D ground penetrating radar (GPR) data into consistent georeferenced point clouds is presented, allowing imaging both the surface and subsurface. Objects such as pipes, cables, and wall structures are made visible as point clouds by thresholding the GPR signal’s Hilbert envelope. The results are verified with existing utility maps. Varying soil conditions, clutter, and noise complicate a fully automatized approach. Topographic correction of the GPR data, by using the LiDAR data, ensures a consistent ground height. Moreover, this work shows that the LiDAR point cloud, as a reference, increases the interpretability of GPR data and allows measuring distances between above ground and subsurface structures.

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

Journal of Glaciology ◽

10.1017/jog.2020.91 ◽

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.

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A Novel Electrically Small Ground-Penetrating Radar Patch Antenna with a Parasitic Ring for Respiration Detection

Sensors ◽

10.3390/s21061930 ◽

2021 ◽

Vol 21 (6) ◽

pp. 1930

Author(s):

Di Shi ◽

Taimur Aftab ◽

Gunnar Gidion ◽

Fatma Sayed ◽

Leonhard M. Reindl

Keyword(s):

Ground Penetrating Radar ◽

Patch Antenna ◽

Low Cost ◽

Substrate Material ◽

Geometric Parameters ◽

Gas Explosions ◽

Aerial Vehicle ◽

Electromagnetic Characteristics ◽

Ground Penetrating ◽

Quick Search

An electrically small patch antenna with a low-cost high-permittivity ceramic substrate material for use in a ground-penetrating radar is proposed in this work. The antenna is based on a commercial ceramic 915 MHz patch antenna with a size of 25 × 25 × 4 mm3 and a weight of 12.9 g. The influences of the main geometric parameters on the antenna’s electromagnetic characteristics were comprehensively studied. Three bandwidth improvement techniques were sequentially applied to optimize the antenna: tuning the key geometric parameters, adding cuts on the edges, and adding parasitic radiators. The designed antenna operates at around 1.3 GHz and has more than 40 MHz continuous −3 dB bandwidth. In comparison to the original antenna, the −3 and −6 dB fractional bandwidth is improved by 1.8 times and 4 times, respectively. Two antennas of the proposed design together with a customized radar were installed on an unmanned aerial vehicle (UAV) for a quick search for survivors after earthquakes or gas explosions without exposing the rescue staff to the uncertain dangers of moving on the debris.

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A Reality Integrated BIM for Architectural Heritage Conservation

Architecture and Design ◽

10.4018/978-1-5225-7314-2.ch006 ◽

2019 ◽

pp. 142-176

Author(s):

Fabrizio Ivan Apollonio ◽

Marco Gaiani ◽

Zheng Sun

Keyword(s):

Laser Scanning ◽

Low Cost ◽

Point Clouds ◽

Information Modeling ◽

Free Form ◽

Architectural Heritage ◽

Ideal Model ◽

Double Curvature ◽

Building Information ◽

Architectural Treatises

Building Information Modeling (BIM) has attracted wide interest in the field of documentation and conservation of Architectural Heritage (AH). Existing approaches focus on converting laser scanned point clouds to BIM objects, but laser scanning is usually limited to planar elements which are not the typical state of AH where free-form and double-curvature surfaces are common. We propose a method that combines low-cost automatic photogrammetric data acquisition techniques with parametric BIM objects founded on Architectural Treatises and a syntax allowing the transition from the archetype to the type. Point clouds with metric accuracy comparable to that from laser scanning allows accurate as-built model semantically integrated with the ideal model from parametric library. The deviation between as-built model and ideal model is evaluated to determine if feature extraction from point clouds is essential to improve the accuracy of as-built BIM.

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Design of Low-Cost Ground Penetrating Radar Receiving Circuit Based on Equivalent Sampling

2019 IEEE International Symposium on Circuits and Systems (ISCAS) ◽

10.1109/iscas.2019.8702465 ◽

2019 ◽

Cited By ~ 1

Author(s):

Zhikuang Cai ◽

Wenhua Lin ◽

Xuanchen Qi ◽

Jian Xiao

Keyword(s):

Ground Penetrating Radar ◽

Low Cost ◽

Ground Penetrating

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Long-term monitoring of reinforcement corrosion in concrete using ground penetrating radar

Corrosion Science ◽

10.1016/j.corsci.2016.11.003 ◽

2017 ◽

Vol 114 ◽

pp. 123-132 ◽

Cited By ~ 38

Author(s):

Shuxian Hong ◽

Herbert Wiggenhauser ◽

Rosemarie Helmerich ◽

Biqin Dong ◽

Peng Dong ◽

...

Keyword(s):

Ground Penetrating Radar ◽

Reinforcement Corrosion ◽

Long Term Monitoring ◽

Ground Penetrating ◽

Term Monitoring

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Extrapolating glacier mass balance to the mountain-range scale: the European Alps 1900–2100

The Cryosphere ◽

10.5194/tc-6-713-2012 ◽

2012 ◽

Vol 6 (4) ◽

pp. 713-727 ◽

Cited By ~ 74

Author(s):

M. Huss

Keyword(s):

Mass Balance ◽

Multiple Regression ◽

Volume Change ◽

Data Series ◽

Glacier Mass Balance ◽

Mountain Range ◽

European Alps ◽

Ice Volume ◽

Area Reduction

Abstract. This study addresses the extrapolation of in-situ glacier mass balance measurements to the mountain-range scale and aims at deriving time series of area-averaged mass balance and ice volume change for all glaciers in the European Alps for the period 1900–2100. Long-term mass balance series for 50 Swiss glaciers based on a combination of field data and modelling, and WGMS data for glaciers in Austria, France and Italy are used. A complete glacier inventory is available for the year 2003. Mass balance extrapolation is performed based on (1) arithmetic averaging, (2) glacier hypsometry, and (3) multiple regression. Given a sufficient number of data series, multiple regression with variables describing glacier geometry performs best in reproducing observed spatial mass balance variability. Future mass changes are calculated by driving a combined model for mass balance and glacier geometry with GCM ensembles based on four emission scenarios. Mean glacier mass balance in the European Alps is −0.31 ± 0.04 m w.e. a−1 in 1900–2011, and −1 m w.e. a−1 over the last decade. Total ice volume change since 1900 is −96 ± 13 km3; annual values vary between −5.9 km3 (1947) and +3.9 km3 (1977). Mean mass balances are expected to be around −1.3 m w.e. a−1 by 2050. Model results indicate a glacier area reduction of 4–18% relative to 2003 for the end of the 21st century.

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Results of experimental tests for the evaluation of the signal-to-noise ratio, short-term stability, linearity in the time axis, and long-term stability of the GPR signal - according to COST Action TU1208 guidelines

10.5194/egusphere-egu2020-18836 ◽

2020 ◽

Author(s):

Milan Vrtunski ◽

Lara Pajewski ◽

Aleksandar Ristić ◽

Željko Bugarinović ◽

Miro Govedarica

Keyword(s):

Ground Penetrating Radar ◽

Signal To Noise Ratio ◽

Experimental Tests ◽

Time Axis ◽

Short Term ◽

Cost Action ◽

Term Stability ◽

Long Term Stability ◽

Ground Penetrating

Ground Penetrating Radar (GPR) systems need to be calibrated on a recurrent basis and their performance shall be periodically verified, in accordance with manufacturer recommendations and specifications. Nevertheless, most GPR owners in Europe employ their radar units and antennas for years without ever having them verified by manufacturers, unless major flaws or issues become evident. In this framework, Members of COST Action TU1208 have recently carried out a critical analysis of the few existing procedures for the calibration and performance verification of GPR systems; and, they have proposed four improved experimental tests to evaluate the signal-to-noise ratio, short-term stability, linearity in the time axis, and long-term stability of the GPR signal [1]. In this work, we present the results of the tests executed in Novi Sad, Serbia, on a GSSI SIR 3000 control unit equipped with GSSI ground-coupled antennas having central frequencies of 400 MHz and 900 MHz. We have experienced that the execution of the tests helps to attain stronger awareness about the behaviour and limits of owned GPR equipment. It is also interesting to check how the results of the tests change over time and in different environmental conditions, to analyze the performance evolution of the equipment. Main aim of this abstract is to spread the voice and encourage GPR owners and manufacturers to execute the tests. If a wide variety of control units and antennas are tested, of older and more recent conception, with different numbers of working hours, reliable thresholds for the tests can be established and the proposed procedures can be further refined and upgraded. Moreover, the results of the tests can be translated into accuracy levels of measured physical and geometrical quantities, to get some awareness about the uncertainty of results of a GPR survey (e.g., achieved accuracy levels in the estimation of layer thicknesses).&#160;[1] L. Pajewski, M. Vrtunski, &#381;. Bugarinovi&#263;, A. Risti&#263;, M. Govedarica, A. van der Wielen, C. Gr&#233;goire, C. Van Geem, X. D&#233;robert, V. Borecky, S. Serkan Artagan, S. Fontul, V. Marecos, and S. Lambot, "GPR system performance compliance according to COST Action TU1208 guidelines,"&#160; Ground Penetrating Radar, Volume 1, Issue 2, Article ID GPR-1-2-1, July 2018, pp. 2-36, doi.org/10.26376/GPR2018007.

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Decay of a long-term monitored glacier: Careser Glacier (Ortles-Cevedale, European Alps)

The Cryosphere ◽

10.5194/tc-7-1819-2013 ◽

2013 ◽

Vol 7 (6) ◽

pp. 1819-1838 ◽

Cited By ~ 38

Author(s):

L. Carturan ◽

C. Baroni ◽

M. Becker ◽

A. Bellin ◽

O. Cainelli ◽

...

Keyword(s):

Mass Loss ◽

Mass Balance ◽

Mass Loss Rate ◽

Regional Scale ◽

European Alps ◽

Systematic Observation ◽

Average Mass ◽

Observation Series ◽

The 19Th Century

Abstract. The continuation of valuable, long-term glacier observation series is threatened by the accelerated mass loss which currently affects a large portion of so-called "benchmark" glaciers. In this work we present the evolution of the Careser Glacier, from the beginning of systematic observation at the end of the 19th century to its current condition in 2012. In addition to having one of the longest and richest observation records among the Italian glaciers, Careser is unique in the Italian Alps for its 46 yr mass balance series that started in 1967. In the present study, variations in the length, area and volume of the glacier since 1897 are examined, updating and validating the series of direct mass balance observations and adding to the mass balance record into the past using the geodetic method. The glacier is currently strongly out of balance and in rapid decay; its average mass loss rate over the last 3 decades was 1.5 m water equivalent per year, increasing to 2.0 m water equivalent per year in the last decade. Although these rates are not representative at a regional scale, year-to-year variations in mass balance show an unexpected increase in correlation with other glaciers in the Alps, during the last 3 decades. If mass loss continues at this pace, the glacier will disappear within a few decades, putting an end to this unique observation series.

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