Advances in radar remote sensing of wetland ecosystems of the Paraná River Delta Region: combination of satellite observations, field data and EM models

HAYDEE KARSZENBAUM; F. M. GRINGS; P. FERRAZZOLI; M. SALVIA; P. KANDUS; PABLO PERNA; J. JACOBO BERLLES

Montreal, Canadá

Simposio; Radarsat II Symposium; 2006

Canadian Space Agency

Corresponding author: H. Karszenabum Email: haydeek@iafe.uba.ar The Paraná River Delta Region constitutes a mosaic of wetlands which covers 17,000 km2 at the end of Del Plata Basin in Argentina. Landforms derived from marine process occurred during the Holocen period and past and present fluvial actions coexist; and they are currently subject to a complex flooding regime which is defined sometimes simultaneously by fluvial regimes from Paraná and Uruguay rivers, the De la Plata estuary tidal regime and local rains. From bio-geographic and ecological point of view, this region has unique characteristics in Argentina. Species of subtropical lineage from the Chaco and Interior Atlantic forest regions penetrate along the rivers Paraná and Uruguay and coexist with other species from the neighboring temperate Pampean and Mesopotamic plains. This area has been observed by ERS 2 and Radarsat I SAR systems. Recently, we analyze the sensitivity of the ENVISAT ASAR instrument to flooding inside marshes. The results of this work were based on: i) the use of multitemporal ASAR data that address different flood conditions in two types of marshes of different structure (cortadera and junco), ii) a radiative transfer model that simulates the backscattering of these marshes and iii) field work corresponding to the acquisition dates. This presentation focuses on the results obtained in the analysis of the temporal series of ERS 2 and Radarsat 1 SAR data, and ENVISAT ASAR data. The complete radar data set over this area includes images from 1997-98 that show the effect of el Niño phenomenon, an ERS 2 temporal set covering 1999-2000 that shows the effect of burning biomass and its recovery on the radar signature, and a temporal set of ASAR data which includes images acquired under different polarizations and incidence angles as well as different environmental conditions (water level, precipitation, and vegetation condition). Two marsh species, named junco and cortadera, were monitored. This overall data set gave us the possibility of studying and understanding the basic interactions between the radar, the soil under different flood conditions, and the vegetation structure. The comprehension of the observed features was addressed through EM models and field data. We also show how the combination of satellite data and EM models offer the possibility of addressing wetland condition mapping (vegetation structure and hydrology). Our future research is related to the use of polarimetric data over this area in order: to investigate the contribution of HV and phase differences in wetland mapping and monitoring, to use polarimetric images to validate our full polarimetric radiative model, and to investigate which is the retrieval potential of polarimetric signatures.