A simplistic incidence angle approach to retrieve the soil moisture and surface roughness at X-band

Abstract

Nowadays, it is an important point of research to classify the moisture and roughness using microwave data with less complex models. For this purpose, microwave measurements were conducted for observing roughness and soil moisture at X-band (9.5 GHz). These measurements were carried out over a range of incidence angle from 20/spl deg/ to 70/spl deg/ at the step of 5/spl deg/ for both polarizations (i.e., horizontal (H) and vertical (V) polarizations). Surface roughness (i.e., root mean square height) and moisture were varied in controlled conditions. Microwave emissivity has been derived with the measurements of reflectivity from a microwave system. Results show a good angular variation of emissivity with surface roughness and moisture for both polarizations. An algorithm is developed using incidence angle as a modulating factor for retrieving the soil moisture and surface roughness at X-band. A good agreement between observed and retrieved surface roughness (i.e., standard error; SE-0.066 for H-polarization) and soil moisture (SE-0.045 for H-polarization) has been obtained by the proposed model.