Comparison of Two Bare-Soil Reflectivity Models and Validation With L-Band Radiometer Measurements

摘要: The emission of bare soils at microwave L-band (1-2 GHz) frequencies is known to be correlated with surface soil moisture. Roughness plays an important role in determining emissivity although it not clear which roughness length scales are most relevant. Small-scale (i.e., smaller than the resolution limit) inhomogeneities across and depth caused by both spatially varying properties topographic features may affect emissivity. In this paper, effects were investigated comparing measured brightness temperatures well-characterized surfaces results from two reflectivity models. selected models air-to-soil transition model Shi's parameterization integral equation (IEM). experimental data taken Surface Monitoring Soil Reservoir Experiment (SMOSREX) consist profiles, permittivities temperatures, 1.4 GHz horizontal vertical polarizations. types correlation functions rough as required evaluate IEM. found clearly more exponential Gaussian. Over period, diurnal mean root square (rms) height decreased, while type function did change. Comparing respect their sensitivities rms revealed distinct differences. Modeled reflectivities tested against derived brightness, showed that perform differently depending on polarization observation angle.