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Published March 29, 2011 | Published
Journal Article Open

Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change

Abstract

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.

Additional Information

© Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 28 September 2010 – Published in The Cryosphere Discuss.: 13 October 2010. Revised: 25 February 2011 – Accepted: 22 March 2011 – Published: 29 March 2011. We would like to thank D. Quincey and T. Bolch for very helpful reviews, the editor J. Bamber for constructive suggestions and S. Khalsa, E. Berthier and T. Haug for other useful short comments. Also, Geir Moholdt for proofing and critically analyzing an earlier version of the manuscript. This study is the result of the IPY-Glaciodyn project (176076) funded by the Norwegian Research Council (NFR), the ESA DUE GlobGlacier project and the ESA Climate Change Initiative (Essential Climate Variable CCI ECV "glaciers and ice caps"). It is also a contribution to the Monitoring Earth surface changes from space study by the Keck Institute for Space Studies at Caltech/JPL. The ASTER individual DEMs were provided within the framework of the Global Land Ice Measurements from Space project (GLIMS) through the USGS LPDAAC and is courtesy of NASA/GSFC/METI/ERSDAC/JAROS and the US/Japan ASTER science team. ASTER GDEM is a product of METI and NASA downloaded freely from the LPDAAC. The ICESat GLAS data were obtained from the NSIDC, Boulder. The SPOT5-HRS DEM (ID: SPI08-025-Svalbard) was obtained through the IPY-SPIRIT program (Korona et al., 2009)© CNES 2008 and SPOT Image 2008 all rights reserved. The SRTM DEM was provided by EROS data center at the US Geological Survey. The NPI DEM and masks were provided in collaboration with the Norwegian Polar Institute. Author Contributions. C. N. developed all algorithms, did all analyses and data interpretations, created the figures, and wrote the paper. A. K. contributed to the concepts, wrote and edited the paper and assisted in interpretations. Edited by: J. L. Bamber

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Created:
August 19, 2023
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October 17, 2023