Microwave response of rough surfaces with auto-correlation functions, RMS heights and correlation lengths using active remote sensing

Abstract

The radar backscattering coefficient of three types of soil surfaces at observation angles (10°- 60°) have been calculated using integral equation model (IEM) for different values of root mean square (RMS) roughness heights and correlation lengths. The surfaces are represented by isotropic autocorrelation functions (exponential, 1.5 power and Gaussian). The dielectric constant (ε) of the soil, an input parameter for the calculation of backscattering coefficient by IEM model, has been determined using wave guide cell method at a single microwave frequency of 9.78 GHz and room temperature 34°C. A positive correlation has been observed between co-polarized (horizontal - horizontal) radar backscattering coefficient and RMS roughness height of the soil surface. Further, the radar backscattering coefficient of soil surface decreases as the angle of observation increases. The variation of backscattering coefficient with correlation length of surface depends on the auto-correlation function and observation angle.