Land surface observation using multi-polarization ENVISAT ASAR data

Multi-polarized space borne SAR data can be used to detect changes in land cover. The ENVISAT ASAR has the ability to acquire images using two polarizations simultaneously. This work discusses the capability of detecting land surface characteristics using ENVISAT ASAR dual polarization data. The applicability of image mode and alternative polarization mode data are investigated, and backscattering coefficients for images with different polarizations are compared. Optical images and GIS data are used as reference data. Two types of land cover in Japan are examined: forest on an active volcano (Miyakejima, a volcanic island that erupted in 2000), and an urban area (central Tokyo). Differences were evident between bare land and forest areas in the HH and HV polarized data sets. City street patterns exhibit differences in backscattering characteristics between like- and crosspolarized SAR images: cross-polarization backscattering is increased for streets that are inclined to the radar irradiation direction.