Full-wave modeling of near-field ground-penetrating radar data for Imaging root water uptake dynamics
(2014) PhD Day ENVITAM — Location: Louvain-la-Neuve (Belgium) (5.March.2014)
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- Abstract
- Root water uptake dynamics at local scale can be studied in laboratory conditions by growing plants in rhizotron containing sand and by imaging the water content evolution of the medium using light transmission. This technique allows to accurately retrieve the water content with high resolution but cannot be applied in opaque medium as leaf-mold or clay, which is a major limitation for more realistic applications. Recently, ground-penetrating radar (GPR) has proven to be one of the most promising techniques for high-resolution digital soil mapping at intermediate scale. Particularly, by using a full-wave inverse modeling of near-field GPR with a high frequency antenna, the electrical properties of soil and their correlated water content with high spatiotemporal resolution can be reconstruct. In this study, we applied the approach by using an ultra-wideband frequency-domain radar with a transmitting and receiving horn antenna operating in the frequency range 3-6 GHz for imaging, in near-field conditions, a rhizotron containing sand subject to different water contents. Synthetic radar data were also generated to examine the well-posedness of the full-waveform inverse problem at high frequencies. Finally, we compared the water content obtained by GPR and light transmission measurements. The results have shown that the near-field modeled and measured GPR data perfectly match in the frequency and time domain for both dry and wet sand. In the case of dry sand, the estimated water content based on GPR and light transmission data was retrieved with small differences. Indeed, the thinness of the sand layer in the rhizotron involves a biggest influence of the air in the GPR signal leading to an underestimate value of the water content. This research shows the potential of the GPR system and the near-field model to accurately estimate the water content of different soils with a high spatial resolution. Future studies will focus on the use of GPR to monitor root water uptake dynamics of plants in several soils systems.
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Mourmeaux, N., Meunier, F., Tran, V. A., & Lambot, S. (2014). Full-wave modeling of near-field ground-penetrating radar data for Imaging root water uptake dynamics. In Lambot Sébastien (ed.), Proceedings (p. p. 33). https://hdl.handle.net/2078.5/200696