Soil Moisture Assessment over an Alpine Hillslope with Significant Soil Heterogeneity
- David Sauerad,
- Steffen Poppbf,
- Angela Dittfurthc,
- Daniel Altdorffbg,
- Peter Dietrichbh and
- Hendrik Paasche
Univ. of Potsdam, Institute of Earth and Environmental Science, Karl-Liebknecht-Str. 24, 14476 Potsdam, Germany Helmholtz Centre for Environmental Research–UFZ, Dep. of Monitoring and Exploration Technologies, Permoserstr. 15, 04318 Leipzig, Germany University of Heidelberg, Institute of Geography, Berliner Str. 48, 69120 Heidelberg, Germany. (current address), Bavarian Environment Agency, Bürgermeister-Ulrich-Str. 160, 86179 Augsburg, Germany (current address), Technische Universität Bergakademie Freiberg, Institute for Drilling Technology and Fluid Mining, Agricolastr. 22, 09596 Freiberg, Germany (current address), Helmholtz Centre for Environmental Research–UFZ, Dep. of Monitoring and Exploration Technologies, Permoserstr. 15, 04318 Leipzig, Germany (current address), Geotechnik Heiligenstadt GmbH, Bautzner Str. 67, 04347 Leipzig, Germany (current address), Forschungszentrum Jülich IBG-3, Wilhelm-Johnen-Str., 52428 Jülich, Germany University of Tübingen, Center for Applied Geosciences, Hölderlinstr. 12, 72074 Tübingen, Germany
We strive to assess soil moisture of an alpine hillslope using time lapse electromagnetic mapping, soil sample analysis and vegetation mapping. Presence of significant soil heterogeneity in combination with required processing of the time lapse data pose a challenge to the extraction of soil moisture information from the geophysical data.
We strive to assess soil water content on a well-studied slow-moving hillslope in Austria. In doing so, we employ time lapse mapping of bulk electrical conductivity using a geophysical electromagnetic induction system operated at low induction numbers. This information is complemented by the acquisition of soil samples for gravimetric water content analysis during one survey campaign. Simple visual soil sample analysis reveals that the upper material in the survey area is a spatially highly variable mixture of predominately sandy, silty, clayey and organic materials. Due to this heterogeneity, classical approaches of mapping soil moisture on the basis of stationary mapping of electrical conductivity variations are not successful. Also the time-lapse approach does not allow ruling out some of the ambiguity inherent to the linkage of bulk electrical conductivity to soil water content. However, indication is found that time-lapse measurements may have supportive capabilities to identify regions of low precipitation infiltration due to high soil saturation. Furthermore, the relationship between the mean electrical conductivity averaged over a full vegetation period and an already available ecological moisture map produced by vegetation analysis is found to resemble closely the relationship observed between gravimetric soil water content and electrical conductivity during the time of sample collection except for highly organic soils. This leads us to the assumption that the relative soil moisture distribution is temporarily stable except for those areas characterized by highly organic soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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