The simplified model of soil dielectric constant and soil moisture at the main frequency points of microwave band

Surface soil moisture is an important parameter in draught monitoring and crop yield estimation, it is important to obtain spatial-temporal soil moisture information in large range. Microwave signal is much related to dielectric constant of object observed, and soil dielectric constant is determined by soil moisture, which was the basis of the use of microwave remote sensing technology for soil moisture monitoring. To solve the transformation of soil moisture and soil dielectric constant, the Dobson semi-empirical model was used to build a simulated database, and then the Hallikainen formula calibrated by the least square regression method at 1.26/1.4/3.2/5.3/6.9 and 9.6GHz frequency-points were performed to set up the simplified models to transform the real part of the dielectric constant to the soil volumetric moisture content. The validations were performed shows that the simplified models have good accuracy and practicability.