Abstract
Abstract. A high resolution surface topography Digital Elevation Model (DEM) is required to underpin studies of the complex glacier system on the Antarctic Peninsula. A complete DEM with better than 200 m pixel size and high positional and vertical accuracy would enable mapping of all significant glacial basins and provide a dataset for glacier morphology analyses. No currently available DEM meets these specifications. We present a new 100-m DEM of the Antarctic Peninsula (63–70° S), based on ASTER Global Digital Elevation Model (GDEM) data. The raw GDEM products are of high-quality on the rugged terrain and coastal-regions of the Antarctic Peninsula and have good geospatial accuracy, but they also contain large errors on ice-covered terrain and we seek to minimise these artefacts. Conventional data correction techniques do not work so we have developed a method that significantly improves the dataset, smoothing the erroneous regions and hence creating a DEM with a pixel size of 100 m that will be suitable for many glaciological applications. We evaluate the new DEM using ICESat-derived elevations, and perform horizontal and vertical accuracy assessments based on GPS positions, SPOT-5 DEMs and the Landsat Image Mosaic of Antarctica (LIMA) imagery. The new DEM has a mean elevation difference of −4 m (± 25 m RMSE) from ICESat (compared to −13 m mean and ±97 m RMSE for the original ASTER GDEM), and a horizontal error of less than 2 pixels, although elevation accuracies are lower on mountain peaks and steep-sided slopes. The correction method significantly reduces errors on low relief slopes and therefore the DEM can be regarded as suitable for topographical studies such as measuring the geometry and ice flow properties of glaciers on the Antarctic Peninsula. The DEM is available for download from the NSIDC website: http://nsidc.org/data/nsidc-0516.html (doi:10.5060/D47P8W9D).
Highlights
The Antarctic Peninsula differs from the rest of the continent in that it is a complex mountainous glacier system: outlet valley glaciers flow from a high elevation plateau region, draining to the east and west of the peninsula, either flowing into ice shelves or terminating as grounded or floating marine glaciers
The principle of the method we present in this paper is that when Global Digital Elevation Model (GDEM) is converted into contours and the erroneous contours are removed, a smooth and realistic new Digital Elevation Model (DEM) can be produced from the remaining contours
We have presented a methodology in which anomalies inherent within ASTER GDEM have been significantly reduced to produce a new DEM for the Antarctic Peninsula between 63–70° S
Summary
The Antarctic Peninsula differs from the rest of the continent in that it is a complex mountainous glacier system: outlet valley glaciers flow from a high elevation plateau region, draining to the east and west of the peninsula, either flowing into ice shelves or terminating as grounded or floating marine glaciers. DEMs of Antarctica have been produced using a range of source data including radar missions, stereo satellite image processing techniques and laser altimetry, but many of these elevation models have a spatial resolution of 1 km or greater and are optimised for coverage of the main Antarctic continent This resolution is insufficient, for the smaller glaciers and the steep-sided coastal regions of the Antarctic Peninsula. The ASTER Global Digital Elevation Model (GDEM) is a recently released nearly global high-resolution DEM, composed of elevation data generated automatically using photogrammetric principles and source data from the Advanced Spaceborne Emission and Reflection Radiometer (ASTER) stereo scenes (ASTER GDEM Validation Team, 2009) It is generally not considered for use in Antarctica due to the wellacknowledged large anomalies in these regions, introduced as a direct result of high reflectance and lack of features on snow-covered plateaus. The new DEM is already being widely used and included in Antarctic datasets, such as BEDMAP2
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