USE OF ERS-2 SAR DATA FOR ESTIMATING SOIL MOISTURE AND VEGETATIONWATER CONTENT VARIATIONS IN BOREAL FORESTS

摘要

The response of ERS-2 SAR to changes in soil andrnforest canopy moisture is investigated at a boreal forestrntest region in Finland. An inversion approach tornestimate moisture characteristics from SAR data isrnapplied. The method requires that a priori informationrnon forest biomass (stem volume) and soil typerndistribution is available. The inversion techniquernprovides estimates that are here, in addition tornbackscattering signatures, directly compared with dailyrnin situ moisture values. The results indicate that timeseriesrnof C-band radar observations can be used for thernmonitoring of boreal forest moisture variations.rnEspecially, the detection of the driest and the wettestrnconditions on mineral soil sites appears to be a feasiblernapplication even for single channel radar. The obtainedrnSAR-based soil moisture estimates showed an RMSErnlevel of 6 %-units against the in situ data for pinedominatedrnmineral soil sites.