DISCRIMINATION OF ROCK GLACIERS ON NEVADO SAJAMA, BOLIVIA, USING REMOTE SENSING

Rock glaciers are an important component of the glacial-periglacial continuum, and their continued monitoring can provide insights into rock glacier dynamics and associated long-term climatic change. The visible to mid-infrared reflectance (from 0.4 mm to 2.5 mm) of representative rock samples obtained from rock glaciers on Nevado Samaja, Bolivia, was measured using an Analytical Spectral Device handheld spectrometer. Spectral differences in the visible to mid-infrared wavelengths were observed between rock glaciers and other surface covers and between different rock glaciers. These spectral differences can be used to provide reliable discrimination between rock glaciers and their surroundings as well as potentially provide an indication of rock glacier activity. A variety of digital image processing techniques, ranging from simple band ratioing to spectral mixture analysis, were used to discriminate rock glaciers in Landsat Thematic Mapper (TM) and Advanced Space Thermal Emission Reflectance Radiometer (ASTER) images. A Digital Elevation Model (DEM) generated from ASTER images was also helpful in discriminating between active and inactive rock glaciers based on their respective elevations. The developed techniques can be used to facilitate the mapping of similar rock glaciers located across the Altiplano Plateau and aid in long-term monitoring of their activity.