Double-Bounce Contribution Effect in the Estimation of Biophysical Parameters of Vegetation Based on PolInSAR TanDEM-X Bistatic Data

Abstract

In this work we provide a detailed analysis of the effect of the double-bounce decorrelation factor on the inversion of scene parameters, with particular focus on the vegetation height. The study employs both simulated data as well as real data acquired over rice fields during the science phase of the TanDEM-X mission. The potential limitations of current inversion approaches are assessed, and the influence of both system parameters (i.e. incidence angle) and scene parameters (i.e. extinction coefficient and ground-to-volume ratios) is evaluated. Results show that the bias in the estimation of scene parameters is higher when the incidence angle is above 30 degrees, i.e for shallow incidences. The normalised vegetation height, i.e. expressed as kv , is used in order to extrapolate the results to other scenarios, e.g. forests.