We chose the Kushiro wetland in Hokkaido, Japan, as a test site to monitor wetland areas. Synthetic aperture radar (SAR) can carry out continuous observation in any weather conditions, and can therefore be used to observe high humidity areas such as wetlands. We applied multi-parameter SAR data (dual-frequency, multi-polarization, and multi-incidence angle) to monitoring the wetland forest. To find the optimum incidence angle and polarization for monitoring the wetland biomass, a simple backscattering model of wetland vegetation was developed and applied to estimate backscattering coefficients for different biomass and surface conditions.
We have acquired ground truth data at Lake Saroma and its surrounding area since 1993 in order to collect data on regional sea ice in the Sea of Okhotsk. The data was acquired in 1999 by Polarimetric and Interferometric SAR (PI-SAR), a dual-frequency, fully polarimetric airborne SAR system jointly developed by the National Space Development Agency of Japan (NASDA) and the Communications Research Laboratory (CRL), simultaneously with ground experiments. This paper describes the results of polarimetric data analysis of typical sea ice observed in the off-shore region near Lake Saroma. Considering sea ice classification capability by using L-band polarimetric SAR data, we found that the correlation coefficients between RR and LL, polarimetric entropy, and polarimetric anisotropy were candidates for discriminating three ice types as well as open water at small incidence angles.