Analysis of ASAR/Envisat polarimetric backscattering characteristics of Doñana national park wetlands

Doñana National Park wetlands, in southwest Spain, undergo yearly cycles of inundation and drying out. These cycles, together with great extensions of annual helophytes, make of Doñana a rapidly changing environment. 43 ASAR/Envisat images of Doñana in HH, VV and HV polarizations were acquired throughout the hydrological year 2006/07 with the aim to monitor in detail an entire flooding cycle. The images were ordered in the seven ASAR swaths to achieve high observation frequency. Backscattering temporal signatures of two main land cover types were obtained in the three polarization configurations and six ASAR swaths. Polarimetric behavior of the signatures is analyzed with the aid of extensive site data, such as a precise digital elevation model and continuous records of water level and meteorological parameters. Conclusions on the feasibility to discriminate emerged versus flooded land are derived for the different incidence angles, land cover types and phenological stages.