|description||The topsoil is a critical transition zone between soil and atmosphere, where important processes like infiltration and evaporation take place that control the water balance in the soil-(plant)-atmosphere continuum. For evaporation from bare soils, theoretical considerations and laboratory experiments suggest the formation of a very dry surface layer that hampers further evaporation due to the break of liquid film continuity from the subsoil to the atmosphere. Since this layer is relatively thin (up to a few cm only), the investigation of this dry layer requires a non-invasive monitoring technique with high resolution, as is provided by single sided NMR (nuclear magnetic resonance). In this master thesis, a NMR sensor will be used to monitor topsoil moisture dynamics at the Selhausen test site (bare soil test site). Monitoring results will be compared to soil-physical model calculations in order to investigate if the formation of a thin dry layer at the soil surface has to be considered under realistic outdoor conditions.
This thesis requires your willingness to come to and work in the Forschungszentrum Jülich for six months.