Soil Moisture Content Monitoring Based on ERS Wind Scatterometer Data

The ERS-1/2 wind scatterometer (WSC) has a low resolution cell of about 50 km but provides a high repe- tition rate (<4 d) and can make measurements at multiple incidence angles. In order to estimate effective surface reflec- tivity (related to soil moisture content) over bare soil using WSC data, an original methodology based on the advance integral equation model (AIEM) is presented, which takes advantage of its multiple view angular characteristics. This method includes two steps. First, a simplified two-parameter surface scattering model is calibrated by AIEM simu- lated-database over a wide parameter space. Second, regression analyses are carried out using the simulated database to build the relation between those parameters of our model at different incident angles from two observations of Mid and Fore beams. From the model simulated database, our technique works quite well in estimating Γ 0 . The possibility of ap- plying the model to retrieve soil moisture is investigated using a set of data collected from the Intensive Observation Period field campaign in 1998 of the Asian Monsoon Experiment Tibet (GAME-Tibet). The retrieved values obtained for the bare land surface are consistent with ground measurements collected in these areas and the correlation coeffi- cient between retrieved soil moisture and the measured one reaches 0.65.

The ERS-1/2 wind scatterometer （WSC） has a low resolution cell of about 50 km but provides a high repetition rate （〈4 d） and can make measurements at multiple incidence angles. In order to estimate effective surface reflectivity （related to soil moisture content） over bare soil Using WSC data, an original methodology based on the advance integral equation model （AIEM） is presented, which takes advantage of its multiple view angular characteristics. This method includes two steps. First, a simplified two-parameter surface scattering model is calibrated by AIEM simulated-database over a wide parameter space. Second, regression analyses are carded out using the simulated database to build the relation between those parameters of our model at different incident angles from two observations of Mid and Fore beams. From the model simulated database, our technique works quite well in estimating Г^0. The possibility of applying the model to retrieve soil moisture is investigated using a set of data collected from the Intensive Observation Period field campaign in 1998 of the Asian Monsoon Experiment Tibet （GAME-Tibet）. The retrieved values obtained for the bare land surface are consistent with ground measurements collected in these areas and the correlation coefficient between retrieved soil moisture and the measured one reaches 0.65.