AMonitoring Technique for SeasonalWater Area Change of Wetland Based on POLSAR Image Analysis

Abstract:
This paper presents a monitoring or classification technique for seasonal change of true water area of wetland based on POLSAR image analysis. The true water area includes not only the body of the water but also the water area under the emerged-plants in the wetland. Statistical POLSAR image analysis using power decomposition scheme is carried out. Resultantly, it is found that the strong double-bounce scattering is observed not only from the emergent-water boundary but also inside the emergent region even when the biomass or the volume density of the emerged-plants is relatively sparse. The dependency of the polarimetric scattering feature on the variation of the volume density is also verified for a simplified emergent-water boundary model by using the Finite-Difference Time-Domain (FDTD) method. It is consequently found that the double-bounce scattering generated from the boundary and/or inside the emerged-plants is utilized as a useful marker for the distinction of the true water area of the wetland. So, by extracting the double-bounce scattering contribution, one can classify the true water area and monitor its change in all seasons.