Ross Ice Shelf Transantarctic outlet glacier surface elevations from 1960-1964
Historical digital elevation models (DEMs) of Darwin/Hatherton, Byrd, Nimrod, Beardmore, Shackleton, Amundsen, and Scott glaciers have been generated for portions of their grounded ice using oblique trimetrogon aerial (TMA) photography with modern-day ground control in structure-from-motion photogra...
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2024
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| Online Access: | http://nbn-resolving.org/urn:nbn:nl:ui:13-0m-9zck https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:344085 |
| Summary: | Historical digital elevation models (DEMs) of Darwin/Hatherton, Byrd, Nimrod, Beardmore, Shackleton, Amundsen, and Scott glaciers have been generated for portions of their grounded ice using oblique trimetrogon aerial (TMA) photography with modern-day ground control in structure-from-motion photogrammetric (SfM) software. The TMA photos were collected over 1960-1964 by the U.S. Navy at high-oblique (>30º) angles at altitudes ranging from 6,100 to 7,600 m. The 9x9 in (23x23 cm) film negatives were digitized decades later by the U.S. Geological Survey at a resolution of 25 μm and freely available for download. A total of 65 oblique photographs were used in sets of three or five (2-3 sets per glacier) in SfM photogrammetric software with ground control of stable terrain that was manually extracted from the Regional Elevation Model of Antarctica (REMA; https://www.pgc.umn.edu/data/rema/) 2 m DEM strips from 2012-2017. 22-30 ground control points were used for each set of processed photos. The final raster products have a gridded resolution of 250 m, are horizontally transformed to WGS84 Antarctic Polar Stereographic (EGSP: 3031), and are vertically projected to WGS84. The mean residual from the camera calibration for all 17 sets of TMA photos is less than 1 pixel and the average error for the ground control points from the bundle adjustment is 2.58 pixels or 2.77 m, -6.38 m, and 0.65 m in the X, Y, and Z in the directions, respectively. The resulting DEMs were co-registered to the REMA datasets over stable terrain (static elevations with slopes <20º) and then differenced to determine the amount of geodetic mass change the outlet glaciers have undergone for ~60 years. To assess the error of the historical DEMs, elevation differences over stable terrain for values within the 95% confidence value were analyzed. The mean difference in elevation values was -3.311 m. The median is -1.895 m and the normalized median absolute deviation is 1.806 m. The total amount of elevation uplift due to isostatic adjustment for ... |
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