• Antarctica;
  • airborne altimetry;
  • digital elevation models;
  • Thwaites Glacier;
  • satellite altimetry

[1] A new airborne altimetry data set collected over Thwaites Glacier, one of Antarctica's most active ice streams, demonstrates the improvement in publicly available digital elevation models (DEMs) of the Antarctic ice sheet. The airborne altimetry comprises 35,000 line km sampled at 20 m along track. The full data set has a relative error of ±20 cm; a reference subset has an error of ±8 cm. These data are offset from ICESat observations by +20 cm. We find that a recently released ICESat DEM provides a good model of the surface of Thwaites Glacier, despite cloud cover and wide track spacings. However, the ICESat DEM's accuracy is an order of magnitude less than that of the ICESat profile data. Our airborne data will serve as an additional temporal reference for the evolution of Thwaites Glacier's surface as well as aid the construction of future high-resolution DEMs.