Combining the Microwave Model Cloud and the Growth Model Promet-v for Soil Moisture Retrieval from Ers-sar Data

Within the frame of the project GeoBIRD (ESA contract 12950/98/NL/GD entitled "Retrieval of geoand bio-physical information from remote sensing data") an attempt was made to derive soil moisture by combining the microwave remote sensing model CLOUD and the land surface process model PROMET-V (PROcess oriented Modular Environment and Vegetation model. Three test sites in Europe, which show different dominant vegetation types were chosen. The CLOUD model was fitted for each of the vegetation types. The plant water content which is a central vegetation parameter required for the CLOUD model was derived from PROMET-V and the backscatter values are extracted from corrected and calibrated ERS data. By inverting the CLOUD model, the spatially distributed soil moisture values can be calculated. These modelled soil moisture results are compared to in situ soil moisture measurements which are available for selected fields in the different testsites. A sensitivity study was carried out and the achieved accuracies are compared and discussed.