Relationship between macrophyte stand variables and radar backscatter at L and C band, Tucuruí reservoir, Brazil
Information on macrophyte distribution in space and time is very important for tropical reservoir management. Macrophyte stands are major sinks/sources of methane and the knowledge of their spatial and temporal variation in biomass is useful for improving the assessment of the role of reservoirs in the carbon cycle. Moreover, macrophyte stands are a driving force in insect-induced diseases such as malaria. In this paper we examine the relationship between macrophyte stand variables such as above-ground biomass, stand average height and moisture, and radar backscatter at C and L bands. The study was carried out in Tucuruí reservoir, where ground data were available concurrently to JERS-1 and RADARSAT overpasses. The results showed that C band is much more sensitive to macrophyte leaf shape than L band. However, L band proved to be more sensitive to above-ground biomass and stand height. Results support the integration of L and C band images to discriminate among the three main genera found in Tucuruí: Typha, Ciperacea and Eicchornia.