Extraction of soil moisture from multitemporal, ERS-1 SLC data of the Freiburg test-site

During May-October 1991 intensive ground-data collection was carried out on four fields to continuously record soil moisture in different depths and to measure weekly agricultural plant parameters (LAI, biomass, height) of different crops. The high temporal resolution of the radar data of almost 3 days during the Commissioning Phase of ERS-1 in 1991 enables the continuous documentation of the change of radar backscatter with changing surface features. Correlations were calculated between the different plant- and soil-parameters and the averaged backscatter from the fields under investigation. A high correlation coefficient of 0.8 was achieved between soil moisture and the grey-values of the test fields in the radar image. The correlation was independent of vegetation cover, and no correlation could be found between plant parameters and the grey-values