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| Titel |
Evaluating of direct ground wave (DGW) method and ground surface-waveform inversion of proximal penetrating radar for mapping shallow soil moisture in the field scale |
| VerfasserIn |
Mohammad Reza Mahmoudzadeh Ardekani, Bas van Wesemael, Khan Zaib Jadoon, Sébastien Lambot |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048634
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| Zusammenfassung |
| Precise measurement of surface soil moisture is essential in different research fields,
including agriculture, surface hydrology and meteorology. We presented two different
approaches for mapping the shallow soil moisture of a bare soil in the field scale, namely
direct ground wave (DGW) using on-ground time-domain ground penetrating radar (GPR)
and surface reflection inversion using off-ground frequency-domain GPR. The soil core
samplings in different depths were performed as a reference measurements. The field
experiments contain two different conditions in the weather namely dry and wet conditions.
A vector network analyzer combined with a horn antenna located 1.1 m above the ground
was used as the off-ground GPR and the effects of roughness was excluded by
operating at the low frequencies (0.2-0.65 GHz). The off-ground inversion based on
ground surface wavelet, was applied to retrieve the dielectric permittivity of the
surface. On-ground pulse GPR was based on common offset (1.1 m) bistatic method
using 2 pairs of 400 MHz bow-tie antenna and the dielectric permittivity of the
shallow soil was retrieved using DGW. The GPR profiles were performed following
thirteen transects in the field and a differential global positioning system (dGPS)
was used for positioning. To convert the GPR derived dielectric permittivity to the
soil moisture, the Topp petrophysical relationship was used. The root mean square
error (RMSE) between the soil moisture measured by off-ground GPR for the dry
condition and soil core sampling was 0.038 cm3.cm-3 in 30 cm depth and for
the on-ground GPR was 0.013 cm3.cm-3 in the same depth. The results for the
wet condition were 0.015 cm3.cm-3 and 0.011 cm3.cm-3 in the 10 cm depth for
off-ground and on-ground respectively. These results show that 1) using on-ground
GPR and DGW for retrieving the shallow soil moisture is more reliable and 2) for
the dry land the off-ground GPR is not able to estimate the shallow soil moisture. |
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