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SFB/TRR 38: Project C4 Phase 1: Hydrological surface processes during the development of an artificial catchment
Project
Project code: keine Angaben
Contract period: 01.01.2007
- 01.01.2010
Purpose of research: Basic research
This project aims at an improved understanding of the influence of orientated surface structures (such as erosion gullies caused by runoff) on soil moisture measurements using microwave radiometry. To develop a radiometer-based method for quantifying the gradual formation of dominant near-surface flow patterns on sandy soils is one of the main goals of this project.
The naturally emitted microwave radiation of a soil is a function of the soil’s surface temperature and its emissivity. Since the emissivity correlates strongly with the soil water content it is possible to determine soil moisture from microwave measurements. Two radiometers measuring at 1.4 GHz (ELBARA) and 11.4 GHz (MORA), respectively, will be used to measure the microwave emission of the soil. The soil surface temperature will be measured separately with an IR-radiometer. Additionally, in-situ measurements of soil moisture and temperature at different depths will be carried out using TDR’s and thermocouples.
The signal received at the radiometer is an integrated value originating from an area of a certain extent (the so-called footprint), the size of which depends on the distance between the radiometer and the observed scene and the viewing angle of the radiometer. We will test a de-convolution algorithm applied to the measured, spatially integrated radiation for its potential to determine sub-footprint fractions of dominant water containing surface areas. Furthermore, parameters characterizing the geometry of these preferential runoff paths will be deduced from the polarization state of the microwave radiation signals.
In the first project stage different test plot experiments have been carried out at the Swiss Federal Research Institute WSL in Birmensdorf (Switzerland). Aim of these experiments was to investigate the influence of different surface patterns on the microwave signatures under controlled conditions.
Section overview
Subjects
- Soil science