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| Titel |
GPR ground wave measurements of soil moisture as local ground truth for remote sensing |
| VerfasserIn |
Patrick Klenk, Stefan Jaumann, Xicai Pan, Ute Wollschlaeger, Kurt Roth |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035122
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| Zusammenfassung |
| Near-surface soil moisture plays an important role for the water and energy cycle at various
scales. At the point scale, processes are already well understood and rapid sensor
development has minimized much of the inherent uncertainty (e.g. Vereecken, 2008). For
estimating soil moisture content at the field to catchment scale, resort is taken to remote
sensing methods, which often rely on extensive ground truth measurements for calibration
(e.g. Robinson, 2008). Up to now, mostly point measurements are used for this. However, due
to subsurface heterogeneity, achieving a representative and robust soil moisture estimate
based on point measurements quickly becomes impractical with growing spatial extent.
Consequently, there is the need to advance fast and efficient methods for reliable estimation
of near-surface soil moisture content to provide local ground truth for remote sensing
measurements.
At scales from a few meters up to a few kilometers, ground-penetrating radar (GPR)
offers fast and efficient access to soil moisture content in the shallow subsurface. Evaluating
the ground wave signal in a GPR survey can yield soil moisture contents in the uppermost
soil section (e.g. Grote (2003), Huisman et al. (2003b)), while multi-channel GPR constitutes
a measurement technique which provides direct access to deeper sections of the soil profile
(Gerhards (2008)).
For achieving a better understanding of the GPR ground wave signal, multi-channel GPR
measurements were carried out on sandy soils at field sites in the Twente area in eastern
Netherlands in October 2008. We here interpret these measurements and verify our
experimental results through numerical simulations. Especially the influence of shallow
reflections and near surface gradients are discussed.
Gerhards, H. (2008). Ground Penetrating Radar as a Quantitative Tool
with Applications in Soil Hydrology, PhD thesis, Heidelberg University.
http://katalog.ub.uni-heidelberg.de/titel/66618434.
Grote, K., Hubbard, S. and Rubin, Y. (2003). Field-scale estimation of volumetric water
content using ground-penetrating radar ground wave techniques. Water Resour. Research
39:1321.
Huisman, J., Hubbard, S., Redman, J. and Annan, A. (2003b). Measuring soil water content
with ground penetrating radar: A review. Vadose Zone Journal 2:476-491.
Robinson, D. A., Campbell, C. S., Hopmans, J. W., Hornbuckle, B. K., Jones, S. B., Knight,
R., Ogden, F., Selker, J. and Wendroth, O. (2008). Soil moisture measurement for ecological
and hydrological watershed-scale observatories: A review. Vadose Zone Journal
7:358-389.
Vereecken, H., Huisman, J. A., Bogena, H., Vanderborght, J., Vrugt, J. A. and Hopmans, J.
W. (2008). On the value of soil moisture measurements in vadose zone hydrology: A review.
Water Resour. Research 44:W00D06. |
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