Andre, Frederic

Jonard, Francois

Jonard, M.

Lambot, S.

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Geophysical Research AbstractsVol. 17, EGU2015-10700, 2015EGU General Assembly 2015© Author(s) 2015. CC Attribution 3.0 License.Characterization of forest litter horizons through full-wave inversion ofground-penetrating radar dataFrédéric André (1), Mathieu Jonard (1), François Jonard (2), and Sébastien Lambot (1)(1) Université catholique de Louvain, Earth and Life Institute, Environmental Sciences, Louvain-la-Neuve, Belgium(frederic.andre@uclouvain.be), (2) Forschungszentrum Jülich, Institute for Bio- and Geosciences, Jülich, GermanyDecomposing litter accumulated at the soil surface in forest ecosystems play a major role in a series of ecosystemprocesses (soil carbon sequestration, nutrient release through decomposition, water retention, buffering of soiltemperature variations, tree regeneration, population dynamics of ground vegetation and soil fauna, ...). Besides,the presence of litter is acknowledged to influence remote sensing radar data over forested areas and accuratequantification of litter radiative properties is essential for proper processing of these data. In these respects,ground-penetrating radar (GPR) presents particular interests, potentially allowing for fast and non-invasivecharacterization of organic layers with fine spatial and/or temporal resolutions as well as for providing detailedinformation on litter electrical properties which are required for modeling either active or passive microwaveremote sensing data.We designed an experiment in order to analyze the backscattering from forest litter horizons and to investi-gate the potentialities of GPR for retrieving the physical properties of these horizons. For that purpose, we usedan ultrawide band radar system connected to a transmitting and receiving horn antenna. The GPR data wereprocessed resorting to full-wave inversion of the signal, through which antenna effects are accounted for. In a firststep, GPR data were acquired over artificially reconstructed layers of three different beech litter types (i.e. (i)recently fallen litter with easily discernible plant organs (OL layer), (ii) fragmented litter in partial decompositionwithout entire plant organs (OF layer) and (iii) combination of OL and OF litter layers) and considering in eachcase a range of layer thicknesses. In a second step, so as to validate the adopted methodology in real naturalconditions, GPR measurements were performed in situ along a transect crossing a wide range of litter propertiesin terms of thickness and composition through stands of various tree species. Results from the controlledexperiment demonstrated the ability of GPR to reconstruct litter horizons, showing close correspondence betweeninversely estimated and measured litter layer thicknesses and providing reliable estimates of litter electromagneticproperties. This experiment also highlighted the necessity of considering scattering and dielectric losses occurringwithin litter for proper modeling of the GPR signal, which was accounted for through frequency dependenceof an effective electrical conductivity of the litter. Similar findings emerged from the in situ experiment, thoughsomewhat lower agreement was observed between estimated and reference layer thickness values. These resultsshow great promise for the use of GPR for non-invasive characterization of forest litter.Index Terms: Ground-penetrating radar (GPR), forest litter, frequency dependence, scatteringReference:André F., Jonard M., Lambot S., 2015. Non-invasive forest litter characterization using full-wave inversion ofmicrowave radar data, IEEE Transactions on Geoscience and Remote Sensing, 53(2), 828–840.

Characterization of forest litter horizons through full-wave inversion of ground-penetrating radar data

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Characterization of forest litter horizons through full-wave inversion of ground-penetrating radar data

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