Journal Article

PreJuSER-17744

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Quantitative Two-Layer Conductivity Inversion of Multi-Configuration Electromagnetic Induction Measurements

Mester, A.FZJ* ; van der Kruk, J.FZJ* ; Zimmermann, E.FZJ* ; Vereecken, H.FZJ*

2011
SSSA Madison, Wis.

This record in other databases:  

Please use a persistent id in citations: doi:10.2136/vzj2011.0035

Abstract: Electromagnetic induction (EMI) measurements return an apparent electrical conductivity that represents a weighted average of the electrical conductivity distribution over a certain depth range. Different sensing depths are obtained for different orientations, different coil off sets, and different frequencies, which, in principle, can be used for a multi-layer inversion. However, instrumental shifts, which often occur in EMI data, prevent the use of quantitative multi-layer inversion. Recently, a new calibration method was developed that uses electrical resistivity tomography (ERT) inversion results and returns quantitative apparent conductivity values. Here, we introduce an inversion scheme that uses calibrated EMI data and inverts for a two-layer earth. The inversion minimizes the misfit between the measured and modeled magnetic field by a combined global and local search and does not use any smoothing parameter. Application of this new scheme to synthetic data demonstrates its efficacy in providing the required physical property information. Inversion of calibrated experimental EMI data using horizontal coplanar (HCP) and vertical coplanar (VCP) loop configurations, coil off sets of 1 and 1.22 m, and frequencies of 8 and 15 kHz provides lateral and vertical conductivity variations very similar to those observed in an elaborate ERT experiment. The inversion is verified using synthetic EMI data calculated from ERT data. Inverting quantitative EMI data using this two-layer inversion enables the quantitative mapping of lateral and vertical electrical conductivity variations over large areas.

Keyword(s): J

Note: We thank the reviewer F. A. Monteiro Santos and two unknown reviewers, the associate editor A. Revil, and co-editor S. Hubbard for their help in improving the manuscript. 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) and 'TERrestrial ENvironmental Observatories' (TERENO).

---

Contributing Institute(s):

1. Agrosphäre (IBG-3)
2. Zentralinstitut für Elektronik (ZEL)

Research Program(s):

1. Terrestrische Umwelt (P24)

Appears in the scientific report 2011

---