Combined analysis of SAR C and TM/Landsat data in the assessment of aquatic vegetation changes in the Tucurui reservoir, Para State, Brazilian Amazon

The objective of this study is to assess the changes in the aquatic vegetation in two different water levels of the Tucurui reservoir. During the SAREX 92 mission, for the first time, remote sensing data from the rising water stage became available for the entire reservoir. SAR-C data obtained over the entire reservoir in the wide mode were processed into a mosaic by the Canadian Centre for Remote Sensing. This mosaic was used to map the areas occupied by different stands of aquatic vegetation in April 1992. TM/Landsat color composite (band 3, 4 and 5) acquired in June 1992 was used to map the stands during the high water stage. The results showed that differences between SAR and TM data prevented the accurate assessment of the changes in the area occupied by aquatic vegetation.