Monitoring seasonal variability of inundated area on the Amazon floodplain with the ERS SAR

Abstract

As part of ongoing efforts to characterize flooding dynamics for characteristic Amazon floodplain sites in support of trace gas and fish ecology studies, ERS-1 SAR data were acquired on a monthly basis between May and December 1995 for an Amazon floodplain site about 80 km west of Manaus, Brazil. The 30-km wide floodplain segment is characterized by large and small lakes, distributory channels, and complex topography. Seasonal inundation by the average 10 m annual rise and fall of the Amazon River floods extensive areas of floodplain forest that provide critical fish habitat. Floating meadows of aquatic grasses have high rates of primary productivity and are important sources for emission of trace gases such as methane. The time series of ERS data was examined to determine the degree to which increased backscattering due to flooding could be observed in open woodland, shrubland, and two types of floodplain forest; whether floating meadow communities could be distinguished from non-flooded grassland; and whether scattering from waves and current lines on large rivers and lakes significantly impaired land/water discrimination. The utility of combining ERS with JERS or Thematic Mapper imagery for floodplain studies will also be discussed.

Keywords: ERS SAR, inundation, Amazon, floodplains

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry