Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet

Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging c apability with sensitivity to hydrologic and climatic snow and ice paramete rs. We use the spaceborne imaging radar-C/X-band synthetic aperture radar ( SIR-C/X-SAR) to map snow and glacial ice on the rugged north slope of Mount Everest. From interferometrically derived digital elevation data, we compu te the terrain calibration factor and cosine of the local illumination angl e. We then process and terrain-correct radar data sets acquired on April 16 , 1994. In addition to the spectral data, we include surface slope to impro ve discrimination among several surface types. These data sets are then use d in a decision tree to generate an image classification. This method is su ccessful in identifying and mapping scree/talus, dry snow, dry snow-covered glacier, wet snow-covered glacier, and rock-covered glacier, as corroborat ed by comparison with existing surface cover maps and other ancillary infor mation. Application of the classification scheme to data acquired on Octobe r 7 of the same year yields accurate results for most surface types but und erreports the extent of dry snow cover.