Abstract
Abstract. Ice-surface elevation profiles of more than 30 000 km in total length are derived from kinematic GNSS (GPS and the Russian GLONASS) observations on sledge convoy vehicles along traverses between Vostok Station and the East Antarctic coast. These profiles have accuracies between 4 and 9 cm. They are used to validate elevation data sets from both radar and laser satellite altimetry as well as four digital elevation models. A crossover analysis with three different processing versions of Envisat radar altimetry elevation profiles yields a clear preference for the relocation method over the direct method of slope correction and for threshold retrackers over functional fit algorithms. The validation of CryoSat-2 low-resolution mode and SARIn mode data sets documents the progress made from baseline B to C elevation products. ICESat laser altimetry data are demonstrated to be accurate to a few decimetres over a wide range of surface slopes. A crossover adjustment in the region of subglacial Lake Vostok combining ICESat elevation data with our GNSS profiles yields a new set of ICESat laser campaign biases and provides new, independent evidence for the stability of the ice-surface elevation above the lake. The evaluation of the digital elevation models reveals the benefits of combining laser and radar altimetry.
Highlights
Surface elevation data are crucial for a broad range of applications in polar sciences
This confirms the findings of Davis (1997), which argued for the superior precision of threshold retrackers
With respect to the kinematic GNSS profiles, the mean bias of all processing versions is negative. This can be explained by the penetration of the radar signal into the upper firn layers
Summary
Surface elevation data are crucial for a broad range of applications in polar sciences. Satellite altimetry is able to provide this information with a high and nearly uniform accuracy and precision for almost the entire Antarctic ice sheet This high accuracy allows us to infer temporal changes in ice surface elevation, which is of prime scientific interest in the context of ongoing climate change (Shepherd et al, 2012; Groh et al, 2014). Bamber, 1994; Roemer et al, 2007) but, as the corrections can exceed 100 m (Brenner et al, 2007), remaining model errors may introduce height errors of up to several metres. This is the major factor limiting the application of SRA in the steep and rugged coastal areas (Flament and Rémy, 2012)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
