High-resolution soil moisture mapping by a proximal ground penetrating radar

A numerical, laboratory and field evaluation

Outline

This thesis aimed at developing a new proximal ground penetrating radar (GPR) for soil moisture sensing and mapping. The GPR we developed is based on a vector network analyzer emulating the radar waves and on off-ground ultra wideband horn antennas. The design of a new Frequency Domain Reflectometry sensor based on the same setup and modeling approach was investigated as well (Minet et al., VZJ, 2010).

For field acquisition, the GPR system was mounted on a mobile platform that allowed for a fast acquisition rate at high spatial resolution (~ m). The impact of shallow soil layering on the GPR backscattered signal was investigated in numerical and laboratory experiments and the best GPR data inversions strategies for dealing with shallow soil layering were determined (Minet et al. IEEE TGRS 2010). Then, coherent two-layered and continuous soil moisture profiles could be retrieved in field conditions (Minet et al. Geoderma, 2011). The uncertainties in soil moisture sensing and mapping were comprehensively evaluated in field conditions, and the proposed GPR method appeared to be highly precise, accurate and repeatable (Minet et al., JH, 2012).

This advanced GPR method permitted to characterize spatiotemporal patterns of soil moisture in an agricultural field and to investigate their temporal stability (Minet et al. WRR, submitted). Lastly, the effect of the spatial variability of antecedent soil moisture on runoff response using a distributed hydrologic model was studied in various field and moisture conditions (Minet et al., HESS, 2011). Benefiting from an unprecedented spatial resolution, the proposed GPR method bridges the scale gap between large-scale remote sensing instruments and small-scale invasive sensors for an accurate soil moisture determination.

PhD-related publications list

An up-to-date publications summary list can be downloaded here.

  • Minet J., Lambot S., Slob E.C. and Vanclooster M. Soil surface water content estimation by fullwaveform GPR signal inversion in the presence of thin layers, IEEE Transactions on Geoscience and Remote Sensing, 2010, 48, 1138-1150. --> [bib] [pdf] [doi]
  • Minet J., Lambot S., Delaide G., Huisman J. A., Vereecken H. and Vanclooster M. A generalized frequency domain reflectometry forward and inverse modeling technique for soil electrical properties determination, Vadose Zone Journal, 2010, 9(4), 1063-1072. --> [bib] [pdf] [doi]
  • Minet J., Wahyudi A., Bogaert P., Vanclooster M. and Lambot S. Mapping shallow soil moisture profiles at the field scale using full-waveform inversion of ground penetrating radar data, Geoderma, 2011, 161, 225- 237. --> [bib] [pdf] [doi]
  • Minet J., Laloy E., Lambot S. and Vanclooster M. Effect of high-resolution spatial soil moisture variability on simulated runoff response using a distributed hydrologic model, Hydrology and Earth System Sciences, 2011, 15, 1323-1338. --> [bib] [pdf] [doi]
  • Minet J., Bogaert P., Vanclooster M. and Lambot S. Validation of ground penetrating radar fullwaveform inversion for field scale soil moisture mapping, Journal of Hydrology, 2012, 424–425, 112–123. --> [bib] [pdf] [doi]
  • Minet J., Verhoest N., Vanclooster M. and Lambot S. Prediction of soil moisture patterns in an agricultural field using temporal stability indicators, submitted to Water Resources Research.

PhD jury

Supervisor
Prof. Sébastien Lambot (UCL, Belgium)
Readers
Prof. Marnik Vanclooster (UCL, Belgium)

Prof. Pierre Defourny (UCL, Belgium)

Prof. Niko Verhoest (UGent, Belgium)

Dr. Johan A. Huisman (FZJ, Germany)

Dr. Laurent Pfister (CRP, Luxembourg)