Validation of ICESat-2 Elevation Accuracy in Antarctica Using CCR Arrays

The Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2), equipped with the Advanced Topographic Laser Altimetry System (ATLAS), enhances ice surface elevation change estimations. ATLAS significantly improves elevation accuracy from over 10 cm, as seen in ICESat’s full-waveform technique, to 2–4 cm. ICESat-2 data’s elevation quality is currently validated at the single-pulse level using the corner cube retroreflector (CCR) method, a terrain-independent technique insensitive to ice surface conditions. This study introduces a cost-effective CCR system for validating ICESat-2 elevation data from Antarctica’s firn surface, complementing the ICESat-2 Science Team’s approach. Through three validation campaigns in Antarctica and Shanghai, China, we enhanced our CCR system in design of the prism hardware, alignment of the CCR array, and determination of valid photon data. We implemented a self-adaptive window determination strategy for valid CCR-returned signal photons to minimize the impact of inadequately returned photons from the Fraunhofer diffraction pattern’s lobes and two closely elevated CCRs. The accurate elevations of single pulses from each CCR were determined and analyzed using global navigation satellite systems (GNSSs) in situ observations during the ICESat-2 overpasses in 2020–2022. Our refined CCR validation system shows that ICESat-2’s pulse elevation has a bias of less than 3.0 cm and a precision of ±1.7 cm in the latest experiment on the Nansen ice shelf, East Antarctica.