The Microwave Backscattering Characteristic Study Of Wheat Based On The Vector Radiative Transfer Theory

Wheat is one of the main food crop. And we in the shadow of food security all the time. So, A wide range, low-cost monitoring to assess the wheat growth and yield is very important. SAR image has the characteristics of wide range and low-cost, and it has the advantages of the all-weather 24 hours a day to monitor. To monitor the wheat by using SAR image, can hardly do without the study of wheat microwave scattering mechanism.The winter wheat crop is the research subject of this paper. On the basis of the advanced Integral Equation Method the Vector Radiative Transfer theory(VRT), a microwave backscatter model of winter wheat is established. This model gives adequate consideration to the growth characteristics of winter wheat, especially the distribution of wheat ears. A double-layer scattering model is built for wheat before heading stage and a three-layer scattering model is built for wheat after the heading stage. In order to validate the correction of this model, the simulation results are compared with the measured values, which shows that the model can effectively simulate the microwave backscattering characteristics of winter wheat. The result of the comparison between simulation results of this winter wheat model and Michigan microwave canopy scattering model(mimics) and experiment results indicates that the winter wheat model has a better cross-polarized simulation results than mimics. At last, a preliminary analysis of wheat is done based on this winter wheat model and the measured values.In this paper, the matlab software is used to write the program of the wheat scattering model and set up a graphical user interface. In this GUI, the self-built model, the measured values and the mimics models are integrated together to comparison easily. Finally, this paper combined with the simulation values of self-built model and measured values to do some exploration from the phase change and the sensitivity of the backscattering coefficient to parameters such as soil roughness, microwave frequency and the permittivity of wheat, which laid the foundation for inversion and application of SAR image.