Comparison of microwave emission model for frozen soil and field observation

Spectral Gradient (SG) is one of indictors that had been used to classify prairie soil as either frozen or thawed. Researchers suggested that negative spectral gradients are caused by volume scattering darkening within the frozen soil. A radiative transfer version of first order that considered volume scattering was used to simulate the brightness temperature of frozen soil. On the basis of sensitivity analysis, the prediction of this model was compared with ground experimental measurements. The results show that the volume scattering effect should be considered when modeling and measured BT of frozen soil especially when the temperature of ground is low.