Soil is one of the most important substance in the Earth system. The change of soil can have great effect on its surrounding environment. Especially, in the research of water cycle of earth system and climate change, it’s very important to precisely simulate emissivity of bare soil. Currently, AIEM is an important model to simulate soil emissivity. And at the same time, it’s need accurate dielectric constant simulation. The three dielectric constant model Mironov, Dboson and Frozen Dielectric model provide the ability to simulate dielectric constant in different conditions. These models can effectively couple with AIEM to precisely simulated soil emissivity.
In retrieval of soil moisture, it is important to precisely simulate scattering and emission of land surface. Compared with traditional land surface scattering model, such as geometric-optics model and physical optics model, IEM can simulate backscattering of land surface in a very wide surface roughness range, and it has been widely used in analysis and simulation of surface scattering and radiation in microwave bands. However, in the derivation of IEM, there is lots of propose which will introduce errors to the model. AIEM is an improvement of IEM, it kept green’s function and absolute phase item of gradient, deduced compensate field coefficients. And at the same time, the AIEM realized the transition from smooth surface to roughness surface, and improved its simulation precision.
Dielectric constant model described the increasing character of dielectric constant as soil moisture increase. The retrieval of soil moisture relies on the relationship of dielectric constant and soil moisture. Dobson model has been widely used in the retrieval of soil moisture. Considering dispersion of dielectric properties of soil, the Dobson model used Debye Equation to calculate complex dielectric constant of water in soil. But it didn’t take into consideration of difference of dielectric properties of combined water and free water. Mironov obtained dielectric constant of combined water and free water in soil by using combined dielectric model based on refractive index, and finally developed Mironov Model. And in the year 2004, Mironov further developed this model by converting complex dielectric constant of soil as a function of soil moisture and frequency. Frozen_Dielectric is a dielectric constant model suitable for frozen soil.
Optical model
