This title appears in the Scientific Report :
2022
Please use the identifier:
http://dx.doi.org/10.1109/TGRS.2021.3107451 in citations.
Please use the identifier: http://hdl.handle.net/2128/30632 in citations.
3-D Electromagnetic Modeling Explains Apparent-Velocity Increase in Crosshole GPR Data-Borehole Fluid Effect Correction Method Enables to Incorporating High-Angle Traveltime Data
3-D Electromagnetic Modeling Explains Apparent-Velocity Increase in Crosshole GPR Data-Borehole Fluid Effect Correction Method Enables to Incorporating High-Angle Traveltime Data
For high-resolution crosshole ground-penetrating radar (GPR) tomography, a wide-range of ray path angles are required, including transmitter-receiver pairs with high-angles. However, artefacts have been observed in the inverted GPR tomograms when high-angle data were incorporated in ray-based invers...
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Personal Name(s): | Mozaffari, Amirpasha (Corresponding author) |
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Klotzsche, Anja / Zhou, Zhen / Vereecken, Harry / van der Kruk, Jan | |
Contributing Institute: |
Jülich Supercomputing Center; JSC Agrosphäre; IBG-3 |
Published in: | IEEE transactions on geoscience and remote sensing, 60 (2022) S. 1 - 10, Art no. 5905710 |
Imprint: |
New York, NY
IEEE
2022
|
DOI: |
10.1109/TGRS.2021.3107451 |
Document Type: |
Journal Article |
Research Program: |
Earth System Data Exploration Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups Agro-biogeosystems: controls, feedbacks and impact |
Link: |
Get full text Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/30632 in citations.
For high-resolution crosshole ground-penetrating radar (GPR) tomography, a wide-range of ray path angles are required, including transmitter-receiver pairs with high-angles. However, artefacts have been observed in the inverted GPR tomograms when high-angle data were incorporated in ray-based inversion (RBI) tomography, due to not well-understood increasing apparent velocities for increasing ray-angles. To reduce these artefacts, it is common practice to limit the angular aperture to a threshold between 30° to 50°, which reduces the spatial resolution. We apply 3D finite-difference time-domain GPR modelling including borehole fluid and resistive loaded finite-length antenna models to study the increase of apparent velocity with increasing ray path angle. This study shows that the strong refraction of the electromagnetic waves at the borehole interface between water and subsurface is one of the reasons for these not well-understood phenomena. We introduce a novel borehole-fluid effect correction (BFEC) that relocates the transmitter and receiver positions to the location where the refraction is occurring to remove any influence of the borehole such that the remaining traveltimes can be inverted using an RBI. BFEC improves the estimated apparent-velocity (relative permittivity) values and enables the incorporation of wide-angle ray paths resulting in more accurate tomograms. We verify the BFEC for a homogenous and realistic synthetic model. By applying curved-ray RBI without and with the BFEC, the subsurface structures are reconstructed with more details for the BFEC data and average relative error model reduced from 13% to under 9% for the high-resolution inhomogeneous model. |