Determination of spatial and temporal soil-moisture development using multitemporal ERS-1 data

Within a project sponsored by DARA, 28 ERS-1 SLC (single look complex) images of an agricultural area in the upper Rhine Valley were processed and integrated into a GIS structure. The GIS contains information on field-boundaries, land-use, soils, and results of continuous soil-moisture and rainfall measurements on several fields in the test site (approx. 50 km2). The GIS is used to establish a relationship between ERS-1 backscatter and measured surface soil-moisture for different land-uses. Since backscatter depends on soil and surface properties, statistical relations between temporal backscatter profiles of different soil- surface complexes are established. They allow us to normalize the multitemporal ERS-1 images to a reference backscatter behavior of corn on loamy sand. Since surface soil-moisture was measured for this soil-surface complex, the ERS-1 images can be converted into reference surface-moisture images. These images are interpreted. Irrigated areas can be identified by their high reference surface-moisture.