Multibaseline POL-InSAR experiment for the estimation of the scattering processes and their spatial distribution within vegetation layers

The interferometric decomposition permits the identification of different scattering mechanisms and the optimization of the interferometric coherence, using the identified mathematically independent phase centers related to these scattering mechanisms. Combining polarimetric and interferometric observables, the polarimetric SAR interferometry (POL-InSAR) technique allows for a more appropriate reconstruction of the quasi-three-dimensional spatial distribution of scattering processes within natural media. The scattering mechanisms occur in different vertical positions and have a physical significance that can be related to certain vegetation structures. The authors have analyzed the interferometric decomposition as a function of the baseline and applied a singular value estimation using a multi-baseline approach. They can show for random volumes that-as a function of baseline-the coherence optimization algorithm is not able to minimize the height distribution of the effective scattering centers within a resolution cell to a single `point´ but optimizes between the ground return and the volume decorrelation. The location of the estimated effective scattering centers is resolved by analyzing the differential phase between interferograms formed using the multi-baseline eigenpolarizations. These results are compared to differential interferometric heights between conventional multi-baseline interferometric elevations at various polarizations without applying the interferometric decomposition to the data set. For this experiment the multi-baseline Lake Baikal (Russia) L-band SIR-C data takes are used