Characterization of forests in Western Sayani Mountains, Siberia from SIR-C SAR data

This paper examines the use of spaceborne radar data 50 map forest types an d logging in the mountainous Western Sayani area in central Siberia. L- and C- band HH-, HV-, and VV-polarized images from the Shuttle Imaging Radar-C instrument were used in the study. Techniques to reduce topographic effect s in the radar images were investigated. These included radiometric correct ion using illumination angle inferred from a digital elevation model and re ducing apparent effects of topography through band ratios. For-est classifi cation was performed after terrain correction utilizing typical supervised techniques and principal component analyses. An ancillary data set of local elevations was also used to improve the forest classification. Map accurac y for each technique was estimated for training sites based on Russian fore stry maps, satellite imagery, and field measurements. The results indicate that it is necessary to correct for topography when attempting to classify forests in mountainous terrain. Radiometric correction based on a digital e levation model improved classification results brit required reducing the s ynthetic aperture radar resolution, to match the digital elevation model. U sing ratios of synthetic aperture radar channels that include cross-polariz ation improved classification and had the advantages of eliminating the nee d for a digital elevation model and preserving the full resolution of the s ynthetic aperture radar data. (C) Elsevier Science Inc., 2001. All Rights R eserved.