DETERMINATION OF INUNDATION AREA IN THE AMAZON RIVER FLOODPLAIN USINGTHE SMMR-37 GHZ POLARIZATION DIFFERENCE

The 37 GHz polarization difference observed by the Scanning Multichann el Microwave Radiometer (SMMR), which was operated on board the Nimbus -7 satellite, provides a sensitive indicator of surface water. These d ata ran provide information on seasonal inundation patterns large trop ical wetlands such as the Amazon River floodplain. Although the SMMR d ata are of low resolution, we were able to estimate the area inundated within a group of pixels by using linear mixing models which incorpor ate the major end-members of the observed microwave signatures. The mo dels were then used to estimate seasonal changes in inundation area ov er a 7-year period for a 34,550 km2 area along the Amazon River near M anaus. The seasonal changes in inundation area determined using mixing models correlate well with changes in river stage.