Microwave subsurface remote sensing in the Negev Desert: monitoring of soil water-content

We report the use of the microwave remote sensing as a technique with great potential for the mapping of subsurface properties including the monitoring of soil water conditions. Remote sensing experiments with microwave instrumentation were conducted in the Negev desert in Israel. The remote sensors used were a P-band (68 cm, 441 MHz) scatterometer and an ERS-2 C-band (5.3 cm, 5.7 GHz) SAR (synthetic aperture radar) along with the collection of ground truth data such as volumetric and gravimetric soil water-content, surface roughness and dielectric measurements. Corner reflectors in the field were used for calibration and geo-rectification of the SAR data. The results of the microwave experiments are in a good agreement with the developed theoretical models that take into account the effects of the random surface roughness. The optical modelling of microwave processes is presented as a tool for developing the physical basis for empirical studies. This practice simplifies testing theoretical predictions and reduces the immense cost of running field and laboratory measurements in the microwave range.