Response of microwave on bare soil moisture and surface roughness by X-band scatterometer

This paper describes an individual effect of soil moisture (m(g)) and surface roughness (h(rms)) of bare soil on the back scattering coefficient (sigma(0)) at the X-band frequency. The study contributes to the design of an efficient microwave sensor. For this pur pose, experimentally observed data was utilized to provide a composite sigma(0) equation model accounting for individual effect in regression analysis. The experimental data are compared with Small Perturbation Method. It is observed that the X-band gives better agreement up to incidence angle 50 degrees for HH-polarization and 60 degrees for VV-polarization as compared to the C-band. The lower angles of incidence give better results than the higher angles for observing m(g) at the X-band. The multiple and partial regression analyses have also carried out for predicting the dependence of scattering coefficient (sigma(0)) on m(g) and h(rms) more accurately. The analyses suggest that the dependence of dielectric constant (i.e., m(g)) is much more significant in comparison to surface roughness at lower angles of incidence for both like polarizations; The results propose the suitable angle of incidence for observing bare surface roughness and soil moisture at the X-band. All these data can be used as a reference for satellite or spaceborne sensors.