Extension of advanced integral equation model for calculations of fully polarimetric scattering coefficient from rough surface

The IEM proposed in 1992, for rough surface scattering has been extensively applied for microwave remote sensing of terrain. Model validation has been made by experimental measurements and by numerical simulations. However, estimation accuracy was verified mostly for like-polarizations in the monostatic configuration. Since then, much effort has been devoted to improving the model performance. A recent AIEM (advanced IEM) incorporated these improvements and demonstrated significant enhancement in accuracy. Analysis was also extended to bistatic scattering for a wide range of surface parameters. In this study, we recognized that both theoretically and experimentally, the modified Stokes vector (Kennaugh matrix), including polarization correlation terms, are very useful to retrieve surface parameters such as wind field. Consequently, we extend the AIEM to include all polarization correlation terms in order to understand the dependence of four Stokes terms on geophysical surface parameters, such as roughness, correlation length, and dielectric constant. Sensitivity analysis is also performed. Another useful aspect is in the physical interpretation of polarimetric returns as a function of azimuthal angle. Potential applications to soil moisture estimation will be illustrated and discussed.