Estimate of net primary production of aquatic vegetation of the Amazon floodplain using SAR satellite data

摘要

Field measurements were combined with synthetic aperture radar images to evaluate the use of RADARSAT and JERS-1 for estimating biomass changes and mapping of aquatic vegetation, and subsequently estimating of net primary productivity of aquatic vegetation in the lower Amazon. The combination of C and L bands provides the best correlation (r =0.82) and an intermediate saturation point (620 gm{sup}(-2)) for estimating above water biomass of aquatic vegetation. A combination of RADARSAT and JERS-1 images from each water period was classified using a region growing algorithm, and yielded an accuracy higher than 95% for the seasonal vegetated areas of the floodplain. The combination of the seasonal mapped area of aquatic vegetation with the statistical SAR-algorithm for estimating above water biomass and the percentage of below water biomass yielded a total annual NPP of 1.9×10{sup}12 g C yr{sup}(-1) (±28%) for aquatic vegetation.