CONICET | Buscador de Institutos y Recursos Humanos

Wetlands are areas where the presence of water at or near the soil surface drives the naturalsystem. Imaging radars (SARs) have distinct characteristics which make them of significantvalue for monitoring and mapping wetland inundation dynamics. The presence or absence ofwater (which has a much higher dielectric constant than dry or wet soil) in wetlands maysignificantly alter the signal detected from these areas depending on the dominant vegetationtype, its density and height. The objective of this paper is to present our current research effortsto explain and correctly simulate the radar response of wetland vegetation/inundation mixtures,and use simulations as an aid for retrieval applications.The radar response of junco marshes under different flood conditions and vegetation stages isanalyzed using a set of 13 multipolarization ENVISAT ASAR scenes acquired over the ParanáRiver Delta marshes during the period 2003-2005. The main aspect of the approach followed isthe simulation of SAR wave interactions with vegetation and water, using an adapted andimproved version of the EM model developed at Tor Vergata University. Obtained resultsindicate that with the refined EM model, it is possible to represent with a good accuracy VV andHH SAR responses of junco marshes for a variety of environmental conditions. Further workand data are needed to explain measured HV backscattering. The general agreement obtainedbetween simulations and observations permitted the development of a simple retrieval scheme,and estimates of water level below the canopy were obtained for different environmentalconditions. RMS errors of forward simulations and retrievals are reported and discussed.