Near-surface soil moisture estimation using AMSR-E brightness temperature

In situ measurement of soil moisture is difficult; extensive and expensive observations are required for good estimation. This is the first study that uses rainfall and runoff data with the water balance equation to calibrate the roughness parameters (h and Q) and to validate satellite soil moisture data. The methodology used the Advanced Microwave Scanning Radiometer (AMSR-E) data and the first-order radiative transfer model in order to retrieve the volumetric soil moisture (vsm). The analysis of two years of data indicates that the estimated daily surface soil moisture is well correlated with the flow observations and a good correlation (R-2 = 0.74) is shown between the water storage change (Delta s) and the soil moisture change (Delta theta). The soil moisture estimated in this new approach would be more relevant to hydrological applications due to its linkage with the rainfall-runoff process.