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Earth Surface Dynamics An interactive open-access journal of the European Geosciences Union
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Volume 5, issue 2
Earth Surf. Dynam., 5, 211-237, 2017
https://doi.org/10.5194/esurf-5-211-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Earth Surf. Dynam., 5, 211-237, 2017
https://doi.org/10.5194/esurf-5-211-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 13 Apr 2017

Research article | 13 Apr 2017

Validation of digital elevation models (DEMs) and comparison of geomorphic metrics on the southern Central Andean Plateau

Benjamin Purinton and Bodo Bookhagen Benjamin Purinton and Bodo Bookhagen
  • Institute of Earth and Environmental Science, Universität Potsdam, Potsdam, Germany

Abstract. In this study, we validate and compare elevation accuracy and geomorphic metrics of satellite-derived digital elevation models (DEMs) on the southern Central Andean Plateau. The plateau has an average elevation of 3.7km and is characterized by diverse topography and relief, lack of vegetation, and clear skies that create ideal conditions for remote sensing. At 30m resolution, SRTM-C, ASTER GDEM2, stacked ASTER L1A stereopair DEM, ALOS World 3D, and TanDEM-X have been analyzed. The higher-resolution datasets include 12m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X DEMs, and 5m ALOS World 3D. These DEMs are state of the art for optical (ASTER and ALOS) and radar (SRTM-C and TanDEM-X) spaceborne sensors.

We assessed vertical accuracy by comparing standard deviations of the DEM elevation versus 307509 differential GPS measurements across 4000m of elevation. For the 30m DEMs, the ASTER datasets had the highest vertical standard deviation at >6.5m, whereas the SRTM-C, ALOS World 3D, and TanDEM-X were all <3.5m. Higher-resolution DEMs generally had lower uncertainty, with both the 12m TanDEM-X and 5m ALOS World 3D having <2m vertical standard deviation. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the low uncertainty across these attributes for SRTM-C (30m), TanDEM-X (12–30m), and ALOS World 3D (5–30m). Single-CoSSC TerraSAR-X/TanDEM-X 10m DEMs and the 30m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and ASTER Stack).

Based on low vertical standard deviations and visual inspection alongside optical satellite data, we selected the 30m SRTM-C, 12–30m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X, and 5m ALOS World 3D for geomorphic metric comparison in a 66km2 catchment with a distinct river knickpoint. Consistent mn values were found using chi plot channel profile analysis, regardless of DEM type and spatial resolution. Slope, curvature, and drainage area were calculated and plotting schemes were used to assess basin-wide differences in the hillslope-to-valley transition related to the knickpoint. While slope and hillslope length measurements vary little between datasets, curvature displays higher magnitude measurements with fining resolution. This is especially true for the optical 5m ALOS World 3D DEM, which demonstrated high-frequency noise in 2–8 pixel steps through a Fourier frequency analysis. The improvements in accurate space-radar DEMs (e.g., TanDEM-X) for geomorphometry are promising, but airborne or terrestrial data are still necessary for meter-scale analysis.

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We evaluate the 12 m TanDEM-X DEM for geomorphometry and compare elevation accuracy (using over 300 000 dGPS measurements) and geomorphic metrics (e.g., slope and curvature) to other modern satellite-derived DEMs. The optically generated 5 m ALOS World 3D is less useful due to high-frequency noise. Despite improvements in radar-derived satellite DEMs, which are useful for elevation differencing and catchment analysis, lidar data are still necessary for fine-scale analysis of hillslope processes.
We evaluate the 12 m TanDEM-X DEM for geomorphometry and compare elevation accuracy (using over...
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