Abstract
Abstract. The Reference Elevation Model of Antarctica (REMA) is the first continental-scale digital elevation model (DEM) at a resolution of less than 10 m. REMA is created from stereophotogrammetry with submeter resolution optical, commercial satellite imagery. The higher spatial and radiometric resolutions of this imagery enable high-quality surface extraction over the low-contrast ice sheet surface. The DEMs are registered to satellite radar and laser altimetry and are mosaicked to provide a continuous surface covering nearly 95 % the entire continent. The mosaic includes an error estimate and a time stamp, enabling change measurement. Typical elevation errors are less than 1 m, as validated by the comparison to airborne laser altimetry. REMA provides a powerful new resource for Antarctic science and provides a proof of concept for generating accurate high-resolution repeat topography at continental scales.
Highlights
Ice sheet surface elevation is among the most fundamental datasets in glaciology
Since existing digital elevation model (DEM) were mostly constructed from satellite ranging data for which errors increase with surface slope, errors tend to be the largest in areas of more complex terrain, such as the coasts, mountain ranges, and outlet glacier interiors (Bamber and Gomez-Dans, 2005)
DEMs were generated from scene pairs using the opensource and fully automated SETSM software package (Noh and Howat, 2017) on the Blue Waters supercomputer at the National Center for Supercomputing Applications (NCSA)
Summary
Ice sheet surface elevation is among the most fundamental datasets in glaciology. Often, investigations aimed at, for example, quantifying mass balance or ice flow modeling are limited by the spatial and temporal resolution and accuracy of surface elevation measurements. For most of Antarctica, continuous grids of surface elevation, generally termed digital elevation models (DEMs), have been limited to spatial resolutions of > 500 m and/or vertical errors reaching tens of meters or more (e.g., DiMarzio et al, 2007; Griggs and Bamber, 2009; Cook et al, 2012; Fretwell et al, 2013; Helm et al, 2014; Slater et al, 2018) This limits their utility for geodetic applications, such as rectifying satellite imagery. Available global DEMs, including the 30 m ASTER GDEM (https://asterweb.jpl.nasa.gov/gdem.asp, last access: 13 February 2019) and recently released 90 m TanDEMX DEM (https://geoservice.dlr.de/web/dataguide/tdm, last access: 13 February 2019) have large errors over ice sheet interiors and, in the case of the latter, include a several-meter bias due to penetration of the X band into firn (Wessel et al, 2018) These DEMs do not have definitive time stamping, limiting their use for elevation change measurements.
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