Effect of the material of rough surfaces and the incident light polarization on the validity of the surface impedance boundary condition and the geometric optics approximation for reflection and emission.

Exact solutions for reflection and emission are compared to different approximations, the surface impedance boundary condition (SIBC) and the geometric optics approximation (GOA). The effects of the incidence angle, the material surfaces, the nature of polarization, and random roughness on the behavior of emissivity and reflectivity have been quantified. The contribution of the effects on the reflection and emission is used to investigate the domains of validity of approximation models.