Multi-temporal radar backscattering measurements and modelling of rice fields using a multi-frequency (L, S, C, and X) scatterometer

This article presents the backscattering coefficients of rice fields obtained using an L-, S-, C-, and X-band scatterometer system during the growth period for a rice field. The system has full-polarizations (VV, VH, HV, and HH) and can view various incidence angles (0°~90°) and azimuth angles (0°~360°). The field measurements were performed in Qionglai County of Chengdu (China) during the 2009 rice-growing season. The rice parameters, including biomass, leaf area index (LAI), and canopy structure, were also measured experimentally in the field. The results indicate that the backscattering coefficients are sensitive to the biomass and LAI. Combined with the rice parameters, the scattering properties of rice growth are analysed using the Monte Carlo model, which relies on a realistic description of the rice, enhancing the backscattering and clustering effects of the scatterers. The model is also improved using more realistic growth characteristics of rice to obtain accurate statistics for the backscattering coefficients, including the random tilt angle of rice stems and the probability density function (PDF) of rice leaves. The modelling results agree quite well with the field measurements of rice backscattering.