Evaluating digital elevation models for glaciologic applications: An example from Nevado Coropuna, Peruvian Andes

摘要: Abstract This paper evaluates the suitability of readily available elevation data derived from recent sensors – Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Shuttle Radar Topography Mission (SRTM) for glaciological applications. The study area is Nevado Coropuna (6426 m), situated in Cordillera Ampato Southern Peru. glaciated was 82.6 km 2 1962, based on aerial photography. We estimate glacier to be ca. 60.8 km 2000, analysis ASTER L1B scene. used two 1:50,000 topographic maps constructed 1955 photography create a digital model with 30 m resolution, which we as reference dataset. Of various interpolation techniques examined, TOPOGRID algorithm found superior other techniques, yielded DEM vertical accuracy ± 14.7 m. compared SRTM (2000) (2001) cell-by-cell basis. Steps included: validating DEM's against field GPS survey points rock areas; visualization such shaded relief contour maps; quantifying errors (bias) each DEM; correlating differences between characteristics (elevation, slope aspect) subtracting elevations RMS error respect non-glaciated areas 23 m. had 61 m displayed 200–300 m horizontal offsets ‘spikes’ when data. Cell-by-cell comparison ASTER-derived showed ablation at toes glaciers (− 25 m − 75 m surface lowering) an apparent thickening summits. mean altitude difference (SRTM minus DEM) − 5 m, pointing towards lowering during period 1955–2000. Spurious values affected thus prevented us changes