A performance comparison of SRTM v. 3.0, AW3D30, ASTER GDEM3, Copernicus and TanDEM-X for tectonogeomorphic analysis in the South American Andes

Abstract

Digital Elevation Models (DEMs) are widely used to assess the degree of tectonic activity in mountainous landscapes. But hardly ever have quality assessments of DEMs been carried out to assess their suitability for the calculation of the most widely used tectonogeomorphic indices. For that reason, we have analysed the five most commonly used DEMs for two tectonic basins in the Peruvian Andes. Those are the 30-m SRTM v.3.0, AW3D30, ASTER GDEM3, Copernicus and the 12-m TanDEM-X. The analysed indices are related to the characteristics of 22 drainage networks and we included a vertical accuracy assessment based on available GNSS control points. Copernicus produced the smoothest river profiles followed by AW3D30 and TanDEM-X. River profiles from the rainforest-covered Moyobamba tectonic basin were noisier than those from the more arid Huancayo tectonic basin. All DEMs performed statistically similar in the calculation of drainage basin area, θ, m/n, Ksn and the Hypsometric Integral. Copernicus and TanDEM-X generated the longest drainage networks. TanDEM-X showed the highest vertical accuracy with a RMSE of 3.174 m in the rugged Huancayo basin, and 2.172 in the Moyobamba basin, followed by AW3D30. Copernicus showed very uneven results between both tectonic basins. TanDEM-X allowed the most detailed mapping of fluvial and tectonic landforms, with the identification of six out of seven fluvial terraces, while Copernicus performed best of all 30-m DEMs. The overall best performing DEMs were Copernicus and TanDEM-X, closely followed by AW3D30. ASTER GDEM3 generally performed worst. In general, there was more statistical variability between DEMs in the more rugged Huancayo basin, suggesting that steeper slopes had a significant impact on the calculated indices. Our results provide a clear guideline for the scientific community of which DEMs to pick for the calculation of the various tectonogeomorphic indices.