TY - JOUR
T1 - Accuracy evaluation of digital elevation models derived from Terrestrial Radar Interferometer over Helheim Glacier, Greenland
AU - Wang, Xianwei
AU - Voytenko, Denis
AU - Holland, David M.
N1 - Funding Information:
We acknowledge Denise Holland from Center for Global Sea Level Change, New York University Abu Dhabi for organizing the field logistics. This research was supported by the Center for Global Sea Level Change (CSLC) of NYU Abu Dhabi Research Institute (G1204), the National Science Foundation (ARC-1304137) of the USA, NASA Oceans Melting Greenland to NYU (NNX15AD55G) and Advanced Polar Science Institute of Shanghai (APSIS). We are grateful to United States Geological Survey (USGS) for free use of Landsat images, to the National Snow and Ice Data Center (NSIDC) for free use of ICESat/GLAS and ICESat-2/ATLAS data. The ArcticDEM is provided by the Polar Geospatial Center under NSF-OPP awards 1043681 and 1559691.
Funding Information:
We acknowledge Denise Holland from Center for Global Sea Level Change, New York University Abu Dhabi for organizing the field logistics. This research was supported by the Center for Global Sea Level Change (CSLC) of NYU Abu Dhabi Research Institute ( G1204 ), the National Science Foundation ( ARC-1304137 ) of the USA, NASA Oceans Melting Greenland to NYU ( NNX15AD55G ) and Advanced Polar Science Institute of Shanghai (APSIS). We are grateful to United States Geological Survey (USGS) for free use of Landsat images, to the National Snow and Ice Data Center (NSIDC) for free use of ICESat/GLAS and ICESat-2/ATLAS data. The ArcticDEM is provided by the Polar Geospatial Center under NSF-OPP awards 1043681 and 1559691.
Publisher Copyright:
© 2021 Elsevier Inc.
PY - 2022/1
Y1 - 2022/1
N2 - Glaciers in polar regions are sensitive to climate and ocean changes and can thin rapidly as a consequence of global warming. Digital Elevation Models (DEMs) from remote sensing observations have been widely used to detect changes in polar glaciers. DEMs from Terrestrial Radar Interferometer (TRI) have recently been used for high frequency glacier change and glacier-ocean interaction studies. However, it is unclear whether TRI DEM over a large study area can be combined directly with remote sensing observations to investigate glacier changes as well as the accuracy of TRI DEM at far range. In this study, we deployed a TRI close to Helheim Glacier, East Greenland and generated DEMs using TRI and satellite laser altimetry. We analyzed the accuracy of the TRI DEM using theoretical calculations, comparisons based on repeat observations, and comparisons with a high accurate ArcticDEM. The validation results suggest that for stable ground surfaces, the uncertainty (standard deviation) is <5 m at range < 9.8 km. Averaging across time (e.g. one hour) decreases the uncertainty almost linearly with range, over 0.5 m to 1.2 m when the range increases from 7.0 km to 10.0 km. Increasing the correlation coefficient threshold for phase unwrapping does not significantly reduce uncertainty. TRI DEMs are influenced by systematic error at far range primarily due to coarse azimuth resolution and phase unwrapping difficulties in discontinuous interferograms. As the absolute accuracy of TRI DEMs is not uniformly distributed in the range direction (farther points have worse uncertainty), our findings indicate that TRI DEMs within range of 10 km can reach <5 m uncertainty, which can be compared with DEMs obtained from remote sensing satellites to detect glacier thinning.
AB - Glaciers in polar regions are sensitive to climate and ocean changes and can thin rapidly as a consequence of global warming. Digital Elevation Models (DEMs) from remote sensing observations have been widely used to detect changes in polar glaciers. DEMs from Terrestrial Radar Interferometer (TRI) have recently been used for high frequency glacier change and glacier-ocean interaction studies. However, it is unclear whether TRI DEM over a large study area can be combined directly with remote sensing observations to investigate glacier changes as well as the accuracy of TRI DEM at far range. In this study, we deployed a TRI close to Helheim Glacier, East Greenland and generated DEMs using TRI and satellite laser altimetry. We analyzed the accuracy of the TRI DEM using theoretical calculations, comparisons based on repeat observations, and comparisons with a high accurate ArcticDEM. The validation results suggest that for stable ground surfaces, the uncertainty (standard deviation) is <5 m at range < 9.8 km. Averaging across time (e.g. one hour) decreases the uncertainty almost linearly with range, over 0.5 m to 1.2 m when the range increases from 7.0 km to 10.0 km. Increasing the correlation coefficient threshold for phase unwrapping does not significantly reduce uncertainty. TRI DEMs are influenced by systematic error at far range primarily due to coarse azimuth resolution and phase unwrapping difficulties in discontinuous interferograms. As the absolute accuracy of TRI DEMs is not uniformly distributed in the range direction (farther points have worse uncertainty), our findings indicate that TRI DEMs within range of 10 km can reach <5 m uncertainty, which can be compared with DEMs obtained from remote sensing satellites to detect glacier thinning.
KW - Accuracy and precision
KW - ArcticDEM
KW - Digital elevation model
KW - Helheim Glacier
KW - ICESat-2/ATLAS
KW - ICESat/GLAS
KW - Terrestrial radar interferometer
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UR - http://www.scopus.com/inward/citedby.url?scp=85117935961&partnerID=8YFLogxK
U2 - 10.1016/j.rse.2021.112759
DO - 10.1016/j.rse.2021.112759
M3 - Article
AN - SCOPUS:85117935961
SN - 0034-4257
VL - 268
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
M1 - 112759
ER -