Evaluating digital elevation models for glaciologic applications: An example from Nevado Coropuna, Peruvian Andes Adina E. Racoviteanu a,b, ⁎ , William F. Manley b , Yves Arnaud c , Mark W. Williams a,b a Department of Geography, University of Colorado, CB 260, Boulder CO 80309, USA b Institute of Arctic and Alpine Research, University of Colorado, CB 450, Boulder CO 80309, USA c Institut de Recherche pour le Développement, UR GREAT ICE, Laboratoire de Glaciologie et Géophysique de l'Environnement, 38402 Saint Martin d'Hères Cedex, France Available online 10 January 2007 Abstract This paper evaluates the suitability of readily available elevation data derived from recent sensors – the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) – for glaciological applications. The study area is Nevado Coropuna (6426 m), situated in Cordillera Ampato of Southern Peru. The glaciated area was 82.6 km 2 in 1962, based on aerial photography. We estimate the glacier area to be ca. 60.8 km 2 in 2000, based on analysis of the ASTER L1B scene. We used two 1:50,000 topographic maps constructed from 1955 aerial photography to create a digital elevation model with 30 m resolution, which we used as a reference dataset. Of the various interpolation techniques examined, the TOPOGRID algorithm was found to be superior to other techniques, and yielded a DEM with a vertical accuracy of ±14.7 m. The 1955 DEM was compared to the SRTM DEM (2000) and ASTER DEM (2001) on a cell-by-cell basis. Steps included: validating the DEM's against field GPS survey points on rock areas; visualization techniques such as shaded relief and contour maps; quantifying errors (bias) in each DEM; correlating vertical differences between various DEM's with topographic characteristics (elevation, slope and aspect) and subtracting DEM elevations on a cell-by-cell basis. The RMS error of the SRTM DEM with respect to GPS points on non-glaciated areas was 23 m. The ASTER DEM had a RMS error of 61 m with respect to GPS points and displayed 200–300 m horizontal offsets and elevation ‘spikes’ on the glaciated area when compared to the DEM from topographic data. Cell-by-cell comparison of SRTM and ASTER-derived elevations with topographic data showed ablation at the toes of the glaciers (- 25 m to - 75 m surface lowering) and an apparent thickening at the summits. The mean altitude difference on glaciated area (SRTM minus topographic DEM) was - 5 m, pointing towards a lowering of the glacier surface during the period 1955–2000. Spurious values on the glacier surface in the ASTER DEM affected the analysis and thus prevented us from quantifying the glacier changes based on the ASTER data. © 2006 Elsevier B.V. All rights reserved. Keywords: Digital Elevation Model (DEM); Geographic Information Systems (GIS); Andes; Glaciology; DEM generation; ASTER; SRTM 1. Introduction Digital elevation models (DEM's) are beginning to see wide use in glaciological applications. Some studies have used DEM's to extract components of glacier Available online at www.sciencedirect.com Global and Planetary Change 59 (2007) 110 – 125 www.elsevier.com/locate/gloplacha ⁎ Corresponding author. Department of Geography, University of Colorado, CB 260, Boulder CO 80309, USA. Tel.: +1 303 492 5546; fax: +1 303 492 6388. E-mail address: racovite@colorado.edu (A.E. Racoviteanu). 0921-8181/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.gloplacha.2006.11.036