Assessment of using ASTER-derived DTM for Glaciological Applications in the Central Andes, Mt. Aconcagua, Argentina

LENZANO M. G

PHOTOGRAMMETRIE, FERNERKUNDUNG, GEOINFORMATION

E SCHWEIZERBARTSCHE VERLAGS

Lugar: Stuttgart; Año: 2013 vol. 3 p. 197 - 208

1432-8364

Monitoring glaciers has recently gained more attention, as efforts to better model climate changes are intensifying worldwide. This paper presents a feasibility study on the implementation and performance assessment of digital terrain models (DTMs), derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) optical imagery, in order to determine the altimetric and volumetric changes on Las Vacas and Horcones Superior glaciers, located at 32° 41’ S and 69° 57’ W in the Mt. Aconcagua area, Mendoza, Argentina. The DTMs were created from ASTER images from 2001 and 2008 in a standard satellite digital photogrammetry environment. To assess the absolute vertical accuracy of the DTMs, GPS data was used, and the results indicated a 24 ± 10 m RMSEz, in topographically complex scenarios and with slopes greater than 30°. To obtain a robust matching as well as to minimize the residuals between DTMs, a 3D conformal transformation was applied to co-register them. To calculate the differences between DTMs, the approach of computing the differences along surface normal vectors was proposed. Next, the changes happened to the glaciers were identified, resulting in −3.15 m/a and −0.92 m/a for Las Vacas and the Horcones Superior, respectively. Finally, the results were tested using the 3D control deformation in order to determine the degree of uncertainty in the estimation of changes in the thickness and volume of glaciers.