Assessment of CryoSat-2 Baseline-D Height Product by GNSS and ICESat-2 in Lambert-Amery System, East Antarctica

Abstract

CryoSat-2 repeatedly collects dense radar altimetry footprints covering high latitudes of the polar ice sheets for over ten years. The Baseline-D height product of CryoSat-2 was recently upgraded and released in 2019. Based on the internal or locally external evaluation of CryoSat-2 Baseline-D ice heights, we extended the validation both heterogeneously and spatially to accomplish a comprehensive assessment. First, reliable ice surface global navigation satellite system point solutions along the 36th Chinese National Antarctic Research Expedition traverse functioned as a height reference for comparison with the CryoSat-2 SAR synthetic aperture radar interferometric mode (SIN) data. Secondly, the Land Ice Along-Track Height product over Lambert–Amery system (LAS) from ice, cloud, and land elevation satellite 2 (ICESat-2), was also applied to validate CryoSat-2 SIN and low-resolution mode (LRM) data. As the results indicate, the SIN height accuracy is evaluated to be −1.68 m ± 2.35 m (slope < 0.65°) along the traverse and −0.96 ± 1.95 m (slope < 0.95° and roughness < 3 m) over the margin of LAS. The LRM height accuracy is evaluated to be −0.13 ± 0.46 m (slope < 0.1° & roughness < 1 m) over the interior of LAS. The standard deviation of the height differences degrades linearly against the limited growth of the terrain slope/roughness at the confidence level of 99%. It is worth noting that the spatially heterogeneous pattern of height differences is correlated with surface topography variations. This article should imply the potential to improve the estimation of mass balance and its uncertainty of polar ice sheets based on radar altimetry data.

Keywords

• Assessment
• Baseline-D
• Cryosat-2
• global navigation satellite system (GNSS)
• ice
• cloud