Critical analysis of microwave scattering response on roughness parameter and moisture content for periodic rough surfaces and its retrieval

Abstract

The main aim of this paper is to accentuate the sensitivity of correlation length 'l' as an important roughness parameter in quantifying the moisture content of bare soil surfaces with specular scattering. For this purpose, an indigenously designed bistatic scatterometer has been used to generate co-polarized specular data at X-band (10GHz) with incidence angle varied from 30°-70° in steps of 10degrees. The moisture and roughness conditions of the bare soil surface were changed under controlled conditions. Twenty seven experimental fields specified on the ground of different roughness and moisture conditions have been analyzed. Higher level of moisture content with larger correlation lengths was found to be more suitable for observing the effect of increasing rms height on specular scattering. Kirchhoff approach (KA) considered under the stationary phase approximation (SPA) has been used as an inversion algorithm with the application of genetic algorithm for the retrieval of soil parameters. A good agreement was observed between the experimental and retrieved values of soil moisture content (mv) and roughness parameters (s and l).