Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change
There are an increasing number of digital elevation models (DEMs) available worldwide for deriving elevation differences over time, including vertical changes on glaciers. Most of these DEMs are heavily post-processed or merged, so that physical error modelling becomes difficult and statistical erro...
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ftcopernicus:oai:publications.copernicus.org:tc8988 2023-05-15T16:22:16+02:00 Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change Nuth, C. Kääb, A. 2018-09-27 application/pdf https://doi.org/10.5194/tc-5-271-2011 https://tc.copernicus.org/articles/5/271/2011/ eng eng doi:10.5194/tc-5-271-2011 https://tc.copernicus.org/articles/5/271/2011/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-5-271-2011 2020-07-20T16:26:09Z There are an increasing number of digital elevation models (DEMs) available worldwide for deriving elevation differences over time, including vertical changes on glaciers. Most of these DEMs are heavily post-processed or merged, so that physical error modelling becomes difficult and statistical error modelling is required instead. We propose a three-step methodological framework for assessing and correcting DEMs to quantify glacier elevation changes: (i) remove DEM shifts, (ii) check for elevation-dependent biases, and (iii) check for higher-order, sensor-specific biases. A simple, analytic and robust method to co-register elevation data is presented in regions where stable terrain is either plentiful (case study New Zealand) or limited (case study Svalbard). The method is demonstrated using the three global elevation data sets available to date, SRTM, ICESat and the ASTER GDEM, and with automatically generated DEMs from satellite stereo instruments of ASTER and SPOT5-HRS. After 3-D co-registration, significant biases related to elevation were found in some of the stereoscopic DEMs. Biases related to the satellite acquisition geometry (along/cross track) were detected at two frequencies in the automatically generated ASTER DEMs. The higher frequency bias seems to be related to satellite jitter , most apparent in the back-looking pass of the satellite. The origins of the more significant lower frequency bias is uncertain. ICESat-derived elevations are found to be the most consistent globally available elevation data set available so far. Before performing regional-scale glacier elevation change studies or mosaicking DEMs from multiple individual tiles (e.g. ASTER GDEM), we recommend to co-register all elevation data to ICESat as a global vertical reference system. Text glacier Svalbard Copernicus Publications: E-Journals New Zealand Svalbard The Cryosphere 5 1 271 290 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
There are an increasing number of digital elevation models (DEMs) available worldwide for deriving elevation differences over time, including vertical changes on glaciers. Most of these DEMs are heavily post-processed or merged, so that physical error modelling becomes difficult and statistical error modelling is required instead. We propose a three-step methodological framework for assessing and correcting DEMs to quantify glacier elevation changes: (i) remove DEM shifts, (ii) check for elevation-dependent biases, and (iii) check for higher-order, sensor-specific biases. A simple, analytic and robust method to co-register elevation data is presented in regions where stable terrain is either plentiful (case study New Zealand) or limited (case study Svalbard). The method is demonstrated using the three global elevation data sets available to date, SRTM, ICESat and the ASTER GDEM, and with automatically generated DEMs from satellite stereo instruments of ASTER and SPOT5-HRS. After 3-D co-registration, significant biases related to elevation were found in some of the stereoscopic DEMs. Biases related to the satellite acquisition geometry (along/cross track) were detected at two frequencies in the automatically generated ASTER DEMs. The higher frequency bias seems to be related to satellite jitter , most apparent in the back-looking pass of the satellite. The origins of the more significant lower frequency bias is uncertain. ICESat-derived elevations are found to be the most consistent globally available elevation data set available so far. Before performing regional-scale glacier elevation change studies or mosaicking DEMs from multiple individual tiles (e.g. ASTER GDEM), we recommend to co-register all elevation data to ICESat as a global vertical reference system. |
format |
Text |
author |
Nuth, C. Kääb, A. |
spellingShingle |
Nuth, C. Kääb, A. Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
author_facet |
Nuth, C. Kääb, A. |
author_sort |
Nuth, C. |
title |
Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
title_short |
Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
title_full |
Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
title_fullStr |
Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
title_full_unstemmed |
Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
title_sort |
co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-5-271-2011 https://tc.copernicus.org/articles/5/271/2011/ |
geographic |
New Zealand Svalbard |
geographic_facet |
New Zealand Svalbard |
genre |
glacier Svalbard |
genre_facet |
glacier Svalbard |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-5-271-2011 https://tc.copernicus.org/articles/5/271/2011/ |
op_doi |
https://doi.org/10.5194/tc-5-271-2011 |
container_title |
The Cryosphere |
container_volume |
5 |
container_issue |
1 |
container_start_page |
271 |
op_container_end_page |
290 |
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1766010227060113408 |