Monitoring flooded area fraction in floodplains of Paraná basin using passive and active microwave systems

Over the past two decades, orbital passive microwave systems have proven to be sensitive to flood condition in large floodplains. This sensitivity is rooted in the well differentiated emission properties of calm water with respect to non-flooded land of any kind. In this paper, AMSR-E observations of an herbaceous wetland area on the Paraná River sub-basin were analyzed during the 2009-10 timeframe when this region was affected by a strong and long lasting flooding. Evident effects on the difference between vertically and horizontally polarized brightness temperatures (ΔT) were observed at C-band. The fraction of vegetated flooded area was estimated by applying an improved algorithm which uses ENVISAT ASAR data at specific dates to calibrate AMSR-E temporal series. Also, using a theoretical emission model, the behavior of ΔT flooded is discussed.