L-Band StripMap-ScanSAR Persistent Scatterer Interferometry in Alpine Environments with ALOS-2 PALSAR-2

The Albula Region in the canton Grisons in Switzerland is prone to a large number of landslides. In order to spatially estimate the surface deformation of these phenomena, we performed a multi-temporal interferometric analysis on point (i.e., persistent scatterers) phases by jointly exploiting ALOS-2 PALSAR-2 ScanSAR and StripMap data acquired along the same orbit. Our results indicate a widespread presence of large-scale rock slope instabilities with linear LOS displacement rates in the range of a few cm/year. In comparison with a PSI Sentinel-1 analysis, valid information is retrieved with L-Band also over forests, where only very limited information is available at C-Band. Over built-up regions and for alpine areas above the tree line, the density of points is higher from Sentinel-1 than from ALOS-2 PALSAR-2 because of the moderate resolution of the ALOS-2 PALSAR-2 ScanSAR data.