Specific biomass indicator for tropical dense forests over hilly terrains derived from the P-band SAR coherency matrix

Forest biomass retrieval using P-band SAR data has been demonstrated during the past 2 decades. However, little effort has been made to recover biomass in tropical forests, with biomass values typically ranges from 250 to 500 t/ha. In this high range of biomass, the radar backscatter coefficients exhibit poor sensitivity to biomass, which is often obscured by perturbing effects. The most important effect is caused by topography, which needs to be corrected before biomass inversion. In this work, we develop a new backscatter coefficient called t⁰ to account for (a) the non reflection symmetry of the forests in case of slopes and (b) the change in angular variation of the backscatter following the change of scattering mechanisms due to slopes. The method is tested on TropiSAR campaign data at two forest sites in French Guiana. The results shows the relevance of proposed correction methods to reduce the effects of topography in dense forests.