Estimating rice growth parameters using X-band scatterometer data

In this study, we constructed an X-band automatic scatterometer system and analyzed scattering characteristics of paddy rice over the whole period of rice growth from transplanting to harvesting. The backscattering coefficients were calculated from the measured data at incidence angle 45° and full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh and dry weight and Leaf Area Index (LAI) that were collected at the same time of each scatterometer measurement. Based on the analysis of the relation between backscattering coefficients at X-band and rice growth parameters, we predicted the rice growth parameters using the radar backscattering data. Relationship between measured and estimated grain dry weight using the X-band backscattering coefficients (VV-polarization) is highly correlated (R²=0.94***). Results from this study show that backscattering coefficients X-band appear effective to estimate rice growth parameters.