Seasonal and diurnal changes of polarimetric parameters from crops derived by the Cloude decomposition theorem at L-band

The objective of this study is to analyse and interpret the seasonal and diurnal changes of polarimetric parameters derived by the Cloude decomposition theorem. The investigations were carried out on polarimetric E-SAR data at L-band. The seasonal scattering behaviour of cereals strongly depends on the local incidence angle. Mainly surface scattering and double bounce processes contribute to the radar backscatter. Broad-leaf crops are characterised by a pronounced contribution of all scattering processes to the radar signal. With respect to diurnal variations of the polarimetric parameters due to dew and interception no significant changes could be determined. Nevertheless, the changes of the σ⁰-values indicate an increase in volume scattering with moisture for all crops, whereby the contribution of the other mechanisms decreases for wet plant surfaces.