Forest Structure Parameter Estimation by Means of Multi-Baseline Pol-InSAR Techniques: Status and Challanges

Polarimetric SAR Interferometry (Pol-InSAR) is a SAR remote sensing discipline with unique and powerful applications related to the vertical structure of natural and man-made volume scatterers. The coherent combination of single- or multi-baseline interferograms acquired at different polarisations provides sensitivity to the vertical distribution of scattering processes and allows their characterisation by using the associated (volume) interferometric coherences [1][2][3][4][5]. Pol-InSAR is today a well-established technique that promises a break-through in solving essential radar remote sensing problems. Indeed, structural parameters of volume scatterers in the biosphere and cryosphere such as vegetation height, structure, biomass, snow depth, and ice layering are today critical inputs for ecological process modeling and enable monitoring and understanding of eco-system change. In this paper we review the actual status of Pol-InSAR techniques and applications in forestry, assess results from actual space (TanDEM-X) and air-borne (FSAR) campaigns and experiments at different frequencies and discuss new potential applications and challenges