This title appears in the Scientific Report :
2010
Please use the identifier:
http://dx.doi.org/10.3997/1873-0604.2010037 in citations.
Electromagnetic induction calibration using apparent electrical conductivity modelling based on electrical resistivity tomography
Electromagnetic induction calibration using apparent electrical conductivity modelling based on electrical resistivity tomography
Electromagnetic parameters of the subsurface such as electrical conductivity are of great interest for non-destructive determination of soil properties (e.g., clay content) or hydrologic state variables (e.g., soil water content). In the past decade, several non-invasive geophysical methods have bee...
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Personal Name(s): | Lavoué, F. |
---|---|
van der Kruk, J. / Rings, J. / André, F. / Moghadas, D. / Huisman, J. A. / Lambot, S. / Weihermüller, L. / Vanderborght, J. / Vereecken, H. | |
Contributing Institute: |
Agrosphäre; ICG-4 JARA-ENERGY; JARA-ENERGY |
Published in: | Near surface geophysics (2010) S. 553 - 561 |
Imprint: |
Houten
EAGE
2010
|
Physical Description: |
553 - 561 |
DOI: |
10.3997/1873-0604.2010037 |
Document Type: |
Journal Article |
Research Program: |
Terrestrische Umwelt |
Series Title: |
Near Surface Geophysics
8 |
Subject (ZB): | |
Publikationsportal JuSER |
Electromagnetic parameters of the subsurface such as electrical conductivity are of great interest for non-destructive determination of soil properties (e.g., clay content) or hydrologic state variables (e.g., soil water content). In the past decade, several non-invasive geophysical methods have been developed to measure subsurface parameters in situ. Among these methods, electromagnetic (EM) induction appears to be the most efficient one that is able to cover large areas in a short time. However, this method currently does not provide absolute values of electrical conductivity due to calibration problems, which hinders a quantitative analysis of the measurement. In this study, we propose to calibrate EM induction measurements with electrical conductivity values measured with electrical resistivity tomography (ERT). EM induction measures an apparent electrical conductivity at the surface, which represents a weighted average of the electrical conductivity distribution over a certain depth range, whereas ERT inversion can provide absolute values for local conductivities as a function of depth. EM induction and ERT measurements were collected along a 120-metre-long transect. To reconstruct the apparent electrical conductivity measured with EM induction, the inverted ERT data were used as input in an electromagnetic forward modelling tool for magnetic dipoles over a horizontally layered medium considering the frequencies and offsets used by the EM induction instruments. Comparison of the calculated and measured apparent electrical conductivities shows very similar trends but a shift in absolute values, which is attributed to system calibration problems. The observed shift can be corrected for by linear regression. This new calibration strategy for EM induction measurements now enables the quantitative mapping of electrical conductivity values over large areas. |