TY  - JOUR
AU  - Lavoué, F.
AU  - van der Kruk, J.
AU  - Rings, J.
AU  - André, F.
AU  - Moghadas, D.
AU  - Huisman, J. A.
AU  - Lambot, S.
AU  - Weihermüller, L.
AU  - Vanderborght, J.
AU  - Vereecken, H.
TI  - Electromagnetic induction calibration using apparent electrical conductivity modelling based on electrical resistivity tomography
JO  - Near surface geophysics
VL  - 8
SN  - 1569-4445
CY  - Houten
PB  - EAGE
M1  - PreJuSER-11993
SP  - 553 - 561
PY  - 2010
N1  - We acknowledge the support by the SFB/TR 32 'Pattern in Soil-Vegetation-Atmosphere Systems: Monitoring, Modelling and Data Assimilation' funded by the Deutsche Forschungsgemeinschaft (DFG). This project was initiated during a three-month internship of F. Lavoue at the Forschungszentrum Juelich. F. Lavoue acknowledges the support of the Ecole Normale Superieure de Lyon, France. Two anonymous reviewers helped to improve the manuscript.
AB  - 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.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000285399200013
DO  - DOI:10.3997/1873-0604.2010037
UR  - https://juser.fz-juelich.de/record/11993
ER  -