In order to evaluate the potential of ENVISAT/ASAR (ENVIronment SATellite /Advanced Synthetic Aperture Radar)
imagery with multi-incidence angle and multi-polarization for Poyang lake wetland study, a microwave canopy
backscatter model for herbaceous vegetation was used to simulate the ASAR backscatter from wetland vegetation at two
different growing status. Field measurements from areas covered with Miscanthus floridulus acquired in middle April and
in May, 2005 were averaged respectively as model inputs to simulate ASAR backscatter from different vegetation
components with seven incidence angles (15° to 45°). In April, 2005, Miscanthus floridulus still has not spread adequately,
HV polarization is more sensitive to vegetation canopy parameters than HH and VV; HH is more suitable for retrieving
surface moisture content and roughness; and VV cannot differentiate the influence of vegetation from surface effects.
Inundation results in significant increment in HV backscatter; for HH, it depends on vegetation growing status, for instance,
a reduction in areas of low vegetation and an increase in areas of high vegetation; for VV polarization, enhancement in total
backscatter is insufficient to be used in flood detection. However, as the height of Miscanthus floridulus is more than 1
meter in late May, the simulated ASAR backscatter is not sensitive to the variations of vegetation parameters, surface
parameters, or even inundation.