Tropical Forest Tree Height and Above Ground Biomass Mapping in Nepal Using Tandem-X and ALOS PALSAR Data

Abstract

In this study, a set of bistatic interferometric SAR images acquired by the TanDEM-X mission are used along with fully polarimetric ALOS PALSAR data for the assessment of tropical forest properties in Nepal. Research to be presented at the conference concentrates on several scientific goals. First, location of interferometric scattering phase centre inside forest canopy is investigated using reference ALS measured canopy height model. Means for forest tree height extraction using both model based approaches (similar to Random Volume over Ground) and semi-empirical models are investigated and reported. It is shown, that forest tree height retrieval is possible with RMSE around 2.8 meters ( $(\mathrm{R}^{2}=0.68$ ). Secondly, correlations between ALOS PALSAR and tropical forest data are analysed, and AGB estimation using fully polarimetric SAR features is performed. Several statistical and non-parametric methodologies were tested and compared. Thirdly, forest AGB estimation is done using both TanDEM-X based tree height and L-band PolSAR features using statistical inversion framework.