Analysis of detailed in-situ soil measurements with ERS C-band radar backscattering data

In order to improve a better quantitative understanding of the effect of soil moisture of bare soils on C-band SAR data, five dedicated "weather" stations with soil moisture probes, rain gauges, and temperature thermometers have been installed through the Flevoland test site (The Netherlands) since April 2000. In addition to the in-situ data, spaceborne SAR data at C-band measured by ERS-2 are also collected (3 images every 70 days), taking advantage that the test site is close-by the locations of the ESA transponders used for calibration of the SAR data. In this paper, the variations of the backscattering coefficient due to soil moisture changes are shown as well as the effect of rain precipitation's on the soil moisture at different depths. Diurnal variations of the soil moisture have been observed during drying periods and soil temperature measurements allow a precise monitoring of this effect.