Abstract

Antarctic digital elevation models (DEMs) are essential for human fieldwork, ice topography monitoring and ice mass change estimation. In the past thirty decades, several Antarctic DEMs derived from satellite data have been published. However, these DEMs either have coarse spatial resolutions or vague time stamps, which limit their further scientific applications. In this study, the new-generation satellite laser altimeter Ice, Cloud, And Land Elevation Satellite-2 (ICESat-2) is used to generate a fine-scale and specific time-stamped Antarctic DEM for both the ice sheet and ice shelves. Approximately 4.69 × 109 ICESat-2 measurement points from November 2018 to November 2019 are used to estimate surface elevations at resolutions of 250 m, 500 m and 1 km based on a spatiotemporal fitting method, which results in a modal resolution of 250 m for this DEM. Approximately 74 % of Antarctica is observed, and the remaining observation gaps are interpolated using the ordinary kriging method. National Aeronautics and Space Administration Operation IceBridge (OIB) airborne data are used to evaluate the generated Antarctic DEM (hereafter called the ICESat-2 DEM) in individual Antarctic regions and surface types. Overall, a median bias of 0.11 m and a root-mean-square deviation of 8.27 m result from approximately 1.4 × 105 spatiotemporally matched grid cells. The accuracy and uncertainty of the ICESat-2 DEM vary in relation to the surface slope and roughness, and more reliable estimates are found in the flat ice sheet interior. The ICESat-2 DEM is superior to previous DEMs derived from satellite altimeters for both spatial resolution and elevation accuracy and comparable to those derived from stereo-photogrammetry and interferometry. The decimeter-scale accuracy and specific time stamp make the ICESat-2 DEM an essential addition to the existing Antarctic DEM groups, and it can be further used for other scientific applications.

Highlights

  • Knowledge of the detailed surface topography in Antarctica is essential for human fieldwork, ice motion tracking and mass balance estimation (Sutterley et al, 2014; Bamber et al, 2009)

  • According to the shaded relief map of Antarctica derived from the ICESat-2 Digital elevation models (DEMs) (Fig. 6), obvious topographical patterns and flat terrain can be found in the mountain environments and ice sheet interior, respectively

  • This DEM has an elevation measurement that accounts for 74% of Antarctica, and the remaining 26% is estimated based on the ordinary kriging method

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Summary

Introduction

Knowledge of the detailed surface topography in Antarctica is essential for human fieldwork, ice motion tracking and mass balance estimation (Sutterley et al, 2014; Bamber et al, 2009). 40 using GeoEye-1 and WorldView-1/2/3 imageries (hereafter called the Reference Elevation Model of Antarctica (REMA) DEM, Howat et al, 2019), and one DEM derived from Interferometric Synthetic Aperture Radar (InSAR) using TerraSARX and TanDEM-X data (hereafter called the TanDEM-X PolarDEM, Wessel et al, 2021). All these DEMs provide reasonable elevation estimates for Antarctica; some flaws still cannot be totally avoided.

Data and Methods
NASA OIB airborne data 80
Surface elevation and uncertainty estimation
DEM evaluation method
General attributes of ICESat-2 DEM
Evaluation of ICESat-2 DEM by comparing to OIB airborne data
Conclusions
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