Accuracy assessment of the global TanDEM-X digital elevation model in a mountain environment

Gdulová, Kateřina; Marešová, Jana; Moudrý, Vítězslav

doi:10.1016/j.rse.2020.111724

Cited by 40 publications

(49 citation statements)

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“…7d). The largest errors are concentrated in the north aspect, as was also reported in previous studies (Gorokhovich and Voustianiouk 2006;Shortridge and Messina 2011), in which they were attributed to the orientation of the sensor (Gdulová et al 2020;Shortridge and Messina 2011). However, here, the data from different sensors all show this aspect dependence, and we infer that it may be related to the accordant distribution of data in different slopes with aspect.…”

Section: Factors Related To the Differences Of Dems: Glacier Elevation Change Terrainsupporting

confidence: 86%

“…Mean error (ME), mean absolute error (MAE), median error, root mean square error (RMSE), standard deviation (STD), and normalized median absolute deviation (NMAD) were calculated for the error assessments. NMAD and ME were used to assess the disturbance from extreme errors (Gdulová et al 2020). 3.…”

Section: Accuracy Assessmentmentioning

confidence: 99%

“…Bearing these issues in mind, and considering the limitations of optics sensors in rugged terrain and the glacier accumulation area , it is clear that a further assessment of the performance of AW3D30 is required. Recently, TanDEM-X (released in 2017) and NASADEM (released in 2020) have been reported to have large improvements in accuracy relative to previous DEM products for various land-cover types (Wessel et al 2018), floodplain sites (Hawker et al 2019), slightly undulating terrain (Altunel 2019), and mountain environments (Gdulová et al 2020). Nonetheless, their performance over the rugged and glacierized TP remains unclear.…”

Section: Introductionmentioning

confidence: 99%

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Towards ice thickness inversion: an evaluation of global DEMs by ICESat-2 in the glacierized Tibetan Plateau

Chen

Zhang

et al. 2021

Preprint

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Abstract. Accurate estimates of regional ice thickness, which are generally produced by ice-thickness inversion models, are crucial for assessments of available freshwater resources and sea level rise. Digital elevation model (DEM) derived surface topography of glaciers is a primary data source for such models. However, the scarce in-situ measurements of glacier surface elevation limit the evaluation of DEM uncertainty, and hence its influence on ice-thickness modelling over the glacierized area of the Tibetan Plateau (TP). Here, we examine the performance over the glacierized TP of six widely used and mainly global-scale DEMs: AW3D30 (30 m), SRTM-GL1 (30 m), NASADEM (30 m), TanDEM-X (90 m), SRTM v4.1 (90 m) and MERIT (90 m) by using ICESat-2 laser altimetry data while considering the effects of glacier dynamics, terrain, and DEM misregistration. The results reveal NASADEM as the best performer, with a small mean error (ME) of −1.0 and a root mean squared error (RMSE) of 12.6 m. A systematic vertical offset existed in AW3D30 (−35.3 ME and 34.9 m RMSE), although it had a similar relative accuracy to NASADEM (~ 13 m STD). TanDEM-X also performs well (−0.1 ME and 15.1 m RMSE), but suffers from serious errors and outliers on steep slopes. SRTM-based DEMs (SRTM-GL1, SRTM v4.1, and MERIT) (all ~ 36 m RMSE) had an inferior performance to NASADEM. However, their errors were reduced in the ablation zone when glacier variations were excluded. Errors in the six DEMs increased from the south-facing to the north-facing aspect and become larger with increasing slope. Misregistration of DEMs relative to ICESat-2 footprint in most glacier areas is small (less than one pixel). An intercomparison of four ice-thickness models: GlabTop2, Open Global Glacier Model (OGGM), Huss-Farinotti (HF), Ice Thickness Inversion Based on Velocity (ITIBOV), show that GlabTop2 is sensitive to the accuracy of both elevation and slope, while OGGM and HF are less sensitive to DEM quality, and ITIBOV is the most sensitive to slope accuracy. Considering the inconsistency of DEMs acquisition dates, NASADEM would be a best choice for ice-thickness estimates over the TP, followed by AW3D30, and TanDEM-X (if steep and high elevation terrain can be avoided). Our assessment figures out the performances of mainly global DEMs over the glacierized TP. This study not only avails the glacier thickness estimation with ice thickness inversion models, but also offered references for other cryosphere studies using DEM.

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Section: Factors Related To the Differences Of Dems: Glacier Elevation Change Terrainsupporting

confidence: 86%

Section: Accuracy Assessmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Towards ice thickness inversion: an evaluation of global DEMs by ICESat-2 in the glacierized Tibetan Plateau

Chen

Zhang

et al. 2021

Preprint

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“…Additionally, the elevation given by the TanDEM-X digital elevation model is also provided in the GEDI products. TanDEM-X elevation values are produced using X-band Synthetic Aperture Radar (SAR) on two satellites, have a resolution of 0.4 arcseconds and in forested, mountainous terrain similar to our study area have a mean error of ±8-10 m [37,38].…”

Section: Gedimentioning

confidence: 99%

Determination of Structural Characteristics of Old-Growth Forest in Ukraine Using Spaceborne LiDAR

Spracklen

2021

Remote Sensing

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A forest’s structure changes as it progresses through developmental stages from establishment to old-growth forest. Therefore, the vertical structure of old-growth forests will differ from that of younger, managed forests. Free, publicly available spaceborne Laser Range and Detection (LiDAR) data designed for the determination of forest structure has recently become available through NASA’s General Ecosystem and Development Investigation (GEDI). We use this data to investigate the structure of some of the largest remaining old-growth forests in Europe in the Ukrainian Carpathian Mountains. We downloaded 18489 cloud-free shots in the old-growth forest (OGF) and 20398 shots in adjacent non-OGF areas during leaf-on, snow-free conditions. We found significant differences between OGF and non-OGF over a wide range of structural metrics. OGF was significantly more open, with a more complex vertical structure and thicker ground-layer vegetation. We used Random Forest classification on a range of GEDI-derived metrics to classify OGF shapefiles with an accuracy of 73%. Our work demonstrates the use of spaceborne LiDAR for the identification of old-growth forests.

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“…Assessment of the accuracy of satellite-based DEMs is based on the comparison with the altitudes provided by high-precision global navigation satellite systems (GNSS) receivers, geodetic marks, and laser scanning data, among other products. For example, Gdulová et al [ 13 ] assessed the vertical accuracy of TanDEM-X DEM (12-meter spatial resolution) over a European mountain environment based on the airborne LiDAR data, presenting vertical accuracy exceeding 30 cm. They found that this product complies with the 10-m mission specification benchmark: in non-forested areas, the LE90 (90% confidence of vertical accuracy) reached values below 6 m, while in coniferous forests, it was equal to or below 12 m. González-Morada and Viveen [ 14 ] compared ASTER GDEM, SRTM, AW3D30, and TanDEM-X DEMs against a set of 139 measurements gathered by a dual-frequency Trimble 5800 Global Navigation Satellite System (GNSS) receiver.…”

Section: Introductionmentioning

confidence: 99%

Conformity of the NASADEM_HGT and ALOS AW3D30 DEM with the Altitude from the Brazilian Geodetic Reference Stations: A Case Study from Brazilian Cerrado

Bettiol

Ferreira

Motta

et al. 2021

Sensors

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The Brazilian Cerrado (tropical savanna) is the second largest biome in South America and the main region in the country for agricultural production. Altitude is crucial information for decision-makers and planners since it is directly related to temperature that conditions, for example, the climatic risk of rainfed crop plantations. This study analyzes the conformity of two freely available digital elevation models (DEMs), the NASADEM Merged Digital Elevation Model Global 1 arc second (NASADEM_HGT) version 1 and the Advanced Land Observing Satellite Global Digital Surface Model (ALOS AW3D30), version 3.1, with the altitudes provided by 1695 reference stations of the Brazilian Geodetic System. Both models were evaluated based on the parameters recommended in the Brazilian Cartographic Accuracy Standard for Digital Cartographic Products (PEC-PCD), which defines error tolerances according to eight different scales (from 1:1000 to 1:250,000) and classes A (most strict tolerance, for example, 0.17 m for 1:1000 scale), B, C, and D (least strict tolerance, for example, 50 m for 1:250,000 scale). Considering the class A, the NASADEM_HGT meets 1:250,000 and lower scales, while AW3D30 meets 1:100,000 and lower scales; for class B, NASADEM_HGT meets 1:100,000 scale and AW3D30 meets 1:50,000. AW3D30 presented lower values of root mean square error, standard deviation, and bias, indicating that it presents higher accuracy in relation to the NASADEM_HGT. Within eight of Cerrado’s municipalities with the highest grain production, the differences between average altitudes, measured by the Cohen’s effect size, were statistically insignificant. The results obtained by the PEC-PCD for the Cerrado biome indicate that both models can be employed in different DEM-dependent applications over this biome.

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Accuracy assessment of the global TanDEM-X digital elevation model in a mountain environment

Cited by 40 publications

References 50 publications

Towards ice thickness inversion: an evaluation of global DEMs by ICESat-2 in the glacierized Tibetan Plateau

Towards ice thickness inversion: an evaluation of global DEMs by ICESat-2 in the glacierized Tibetan Plateau

Determination of Structural Characteristics of Old-Growth Forest in Ukraine Using Spaceborne LiDAR

Conformity of the NASADEM_HGT and ALOS AW3D30 DEM with the Altitude from the Brazilian Geodetic Reference Stations: A Case Study from Brazilian Cerrado

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