Correlation between near-surface electromagnetic soil parameters and early-time GPR signals: An experimental study

Geophysics ◽  
2007 ◽  
Vol 72 (2) ◽  
pp. A25-A28 ◽  
Author(s):  
Elena Pettinelli ◽  
Giuliano Vannaroni ◽  
Barbara Di Pasquo ◽  
Elisabetta Mattei ◽  
Andrea Di Matteo ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Early Time ◽  
Test Site ◽  
Time Domain Reflectometry ◽  
Soil Parameters ◽  
Time Interval ◽  
Near Surface ◽  
Novel Approach ◽  
Natural Test ◽  
Ground Penetrating

We explore a new approach to evaluate the effect of soil electromagnetic parameters on early-time ground-penetrating radar (GPR) signals. The analysis is performed in a time interval which contains the direct airwaves and ground waves, propagating between transmitting and receiving antennas. To perform the measurements we have selected a natural test site characterized by very strong lateral gradient of the soil electrical properties. To evaluate the effect of the subsoil permittivity and conductivity on the radar response we compare the envelope amplitude of the GPR signals received in the first [Formula: see text] within [Formula: see text]-wide windows, with the electrical properties ([Formula: see text] and [Formula: see text]) determined using time-domain reflectometry (TDR). The results show that the constitutive soil parameters strongly influence early-time signals, suggesting a novel approach for estimating the spatial variability of water content with GPR.

scholarly journals Investigating the Performance of Bi-Static GPR Antennas for Near-Surface Object Detection

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 170 ◽  
Author(s):  
Xianyang Gao ◽  
Frank J. W. Podd ◽  
Wouter Van Verre ◽  
David J. Daniels ◽  
Anthony J. Peyton
Keyword(s):  
Ground Penetrating Radar ◽  
Input Impedance ◽  
Test Site ◽  
Late Time ◽  
Near Surface ◽  
Object Depth ◽  
Ground Penetrating ◽  
Antenna Input ◽  
Surface Object ◽  
Bow Tie

Antennas are an important component in ground penetrating radar (GPR) systems. Although there has been much research reported on the design of individual antennas, there is less research reported on the design of the geometry of bi-static antennas. This paper considers the effects of key parameters in the setup of a GPR head consisting of a bi-static bow-tie pair to show the effect of these parameters on the GPR performance. The parameters investigated are the antenna separation, antenna height above the soil, and antenna input impedance. The investigation of the parameters was performed by simulation and measurements. It was found when the bi-static antennas were separated by 7 cm to 9 cm and were operated close to the soil (2 cm to 4 cm), the reflected signal from a near-surface object is relatively unaffected by height variation and object depth. An antenna input impedance of 250 Ω was chosen to feed the antennas to reduce the late-time ringing. Using these results, a new GPR system was designed and then evaluated at a test site near Benkovac, Croatia.

Pitfalls in near-surface geophysical interpretation: Challenging paradigms and misconceptions

2018 ◽  
Vol 6 (4) ◽  
pp. SL1-SL9 ◽  
Author(s):  
David C. Nobes ◽  
Estella Atekwana
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Ground Penetrating Radar ◽  
Nonaqueous Phase Liquids ◽  
Potential Fields ◽  
Near Surface ◽  
Geophysical Interpretation ◽  
Occam’S Inversion ◽  
Ground Penetrating

Too often, ideas become so well-established that they take on the roles of paradigms, and challenging those paradigms can be difficult, even if they are flawed. Similarly, misconceptions can take root and become firmly entrenched and again are difficult to dislodge. Both of these situations are fundamentally unscientific. Science makes progress when established theories are shown to be incorrect or at least incomplete. To do that, we have to let the data that we collect tell their stories. We should not impose models upon the data, but rather allow the data to yield those models that best represent those features that are absolutely necessary to fit the data, an approach often called “Occam’s inversion.” We also should not impose nonphysical and unscientific limits on our interpretation models. We evaluate several examples from our own experiences: the electrical properties of faults, nonuniqueness in potential fields, the influence of nonaqueous phase liquids and water on ground-penetrating radar and electrical resistivity, and the geophysical response of seafloor mineralization. In each case, a reviewer or another scientist questioned the conclusions using unscientific or incorrect arguments or assumptions. We must let the data speak.

scholarly journals GPR imaging of traffic compaction effects on soil structures

2021 ◽  
Author(s):  
Akinniyi Akinsunmade
Keyword(s):  
Test Site ◽  
Survey Method ◽  
Natural Setting ◽  
Soil Horizons ◽  
Near Surface ◽  
Soil Structures ◽  
Geophysical Technique ◽  
Ground Penetrating ◽  
Soil Subsurface ◽  
Made In

AbstractSpatial and depth variability of soil characteristics greatly influence its optimum utilization and management. Concealing nature of soil subsurface horizons has made the traditional soil investigations which rely on point information less reliable. In this study, an alternative use of ground penetrating radar (GPR)—a near-surface geophysical survey method—was tested to address the shortcomings. The focus of the study was on assessment of characteristics variability of soil layers at a test site and evaluation of effects of compaction caused by machinery traffics on soil. GPR methods utilize electromagnetic energy in the frequency range of 10 MHz and 3.0 GHz. Fourteen profiles GPR data were acquired at the test site-a farmland in Krakow, Poland. Compaction on parts of the soil was induced using tractor movements (simulating traffic effects) at different passes. Data were processed using basic filtering algorithms and attributes computations executed in Reflexw software. Attempt made in the study was on use of GPR geophysical technique for soil assessment. The method allows delineation of the soil horizons which depicts characteristic depth changes and spatial variability within the horizons. Moreover, traffic effects that caused compaction on parts of the soil horizons were discernable from the GPR profile sections. Thus, similar densification like hardpan that may develop in natural setting can be investigated using the method. The results have shown the suitability of the method for quick, noninvasive and continuous soil investigation that may also allow assessment of temporal soil changes via repeated measurement.

Frontal Rainfall Observation by a Commercial Microwave Communication Network

2009 ◽  
Vol 48 (7) ◽  
pp. 1317-1334 ◽  
Author(s):  
Artem Zinevich ◽  
Hagit Messer ◽  
Pinhas Alpert
Keyword(s):  
Communication Network ◽  
Rain Rate ◽  
Temporal Dynamics ◽  
Rain Gauge ◽  
Time Interval ◽  
Time Model ◽  
Near Surface ◽  
Novel Approach ◽  
Spatial Reconstruction ◽  
Microwave Communication

Abstract A novel approach for reconstruction of rainfall spatial–temporal dynamics from a wireless microwave network is presented. It employs a stochastic space–time model based on a rainfall advection model, assimilated using a Kalman filter. The technique aggregates the data in time and space along the direction of motion of the rainfall field, which is recovered from the simultaneous observation of a multitude of microwave links. The technique is applied on a standard microwave communication network used by a cellular communication system, comprising 23 microwave links, and it allows for observation of near-surface rainfall at the temporal resolutions of 1 min. The accuracy of the method is demonstrated by comparing instantaneous rainfall estimates with measurements from five rain gauges, reaching correlations of up to 0.85 at the 1-min time interval with a bias and RMSE of −0.2 and 4.2 mm h−1, respectively, and up to 0.96 with RMSE of 1.6 mm h−1 at the 10-min time interval for a 22-h intensive rainstorm with an average rain rate of 3.0 mm h−1 and a peak rain rate of 84 mm h−1. The results are compared with those of other spatial reconstruction techniques. The proposed dynamic rainfall reconstruction approach can be applied to larger-scale dynamic rainfall assimilation methods, enabling interpolation over data-void regions and straightforward incorporation of data from other sources, for example, rain gauge networks and radars.

scholarly journals A Prototype System for Time-Lapse Electrical Resistivity Tomographies

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Raffaele Luongo ◽  
Angela Perrone ◽  
Sabatino Piscitelli ◽  
Vincenzo Lapenna
Keyword(s):  
Electrical Resistivity ◽  
Time Lapse ◽  
Test Site ◽  
Rain Gauge ◽  
Time Domain Reflectometry ◽  
Acquisition Time ◽  
Time Interval ◽  
Prototype System ◽  
Resistivity Tomography ◽  
Rainwater Infiltration

A prototype system for time-lapse acquisition of 2D electrical resistivity tomography (ERT) and time domain reflectometry (TDR) measurements was installed in a test site affected by a landslide in Basilicata region (southern Italy). The aim of the system is to monitor in real-time the rainwater infiltration into the soil and obtain information about the variation of the water content in the first layers of the subsoil and the possible influence of this variation on landslide activity. A rain gauge placed in the test site gives information on the rainfall intensity and frequency and suggests the acquisition time interval. The installed system and the preliminary results are presented in this paper.

scholarly journals Integration of high resolution geophysical methods. Detection of shallow depth bodies of archaeological interest

1998 ◽  
Vol 41 (3) ◽  
Author(s):  
F. Cammarano ◽  
P. Mauriello ◽  
D. Patella ◽  
S. Piro ◽  
F. Rosso ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Geophysical Methods ◽  
Test Site ◽  
Governing Parameter ◽  
Near Surface ◽  
Magnetic Methods ◽  
Acquisition Mode ◽  
2D Data ◽  
Ground Penetrating ◽  
Self Potential

A combined survey using ground penetrating radar, self-potential, geoelectrical and magnetic methods has been carried out to detect near-surface tombs in the archaeological test site of the Sabine Necropolis at Colle del Forno, Rome, Italy. A 2D data acquisition mode has been adopted to obtain a 3D image of the investigated volumes. The multi-methodological approach has not only demonstrated the reliability of each method in delineating the spatial behaviour of the governing parameter, but mainly helped to obtain a detailed physical image closely conforming to the target geometry through the whole set of parameters involved.

Imaging the internal structure of trunks via multiscale phase inversion of ground-penetrating radar data

2021 ◽  
pp. 1-53
Author(s):  
Lei Fu ◽  
Lanbo Liu
Keyword(s):  
Dielectric Constant ◽  
Internal Structure ◽  
Ground Penetrating Radar ◽  
Phase Inversion ◽  
Multiscale Approach ◽  
White Oak ◽  
Near Surface ◽  
Oak Tree ◽  
Ground Penetrating ◽  
Constant Distribution

Ground-penetrating radar (GPR) is a geophysical technique widely used in near-surface non-invasive detecting. It has the ability to obtaining a high-resolution internal structure of living trunks. Full wave inversion (FWI) has been widely used to reconstruct the dielectric constant and conductivity distribution for cross-well application. However, in some cases, the amplitude information is not reliable due to the antenna coupling, radiation pattern and other effects. We present a multiscale phase inversion (MPI) method, which largely matches the phase information by normalizing the magnitude spectrum; in addition, a natural multiscale approach by integrating the input data with different times is implemented to partly mitigate the local minimal problem. Two synthetic GPR datasets generated from a healthy oak tree trunk and from a decayed trunk are tested by MPI and FWI. Field GPR dataset consisting of 30 common shot GPR data are acquired on a standing white oak tree (Quercus alba); the MPI and FWI methods are used to reconstruct the dielectric constant distribution of the tree cross-section. Results indicate that MPI has more tolerance to the starting model, noise level and source wavelet. It can provide a more accurate image of the dielectric constant distribution compared to the conventional FWI.

The Effect of As+ Ion Implantation and Annealing on the Electrical Properties of Near-Surface Layers in Graded-Gap n-Hg0.78Cd0.22Te Films

2021 ◽  
Vol 47 (2) ◽  
pp. 189-192
Author(s):  
A. V. Voitsekhovskii ◽  
S. N. Nesmelov ◽  
S. M. Dzyadukh ◽  
V. S. Varavin ◽  
S. A. Dvoretskii ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Ion Implantation ◽  
Surface Layers ◽  
Near Surface
Sign in / Sign up

Export Citation Format

Share Document