Articles | Volume 11, issue 3
Research article
05 May 2017
Research article |  | 05 May 2017

Validation of satellite altimetry by kinematic GNSS in central East Antarctica

Ludwig Schröder, Andreas Richter, Denis V. Fedorov, Lutz Eberlein, Evgeny V. Brovkov, Sergey V. Popov, Christoph Knöfel, Martin Horwath, Reinhard Dietrich, Alexey Y. Matveev, Mirko Scheinert, and Valery V. Lukin

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.

Short summary
The paper describes the processing of kinematic GNSS data observed over nine seasons in East Antarctica. The obtained surface elevation profiles are used to validate several data sets of satellite altimetry. Thus, we find a clear recommendation that processing versions provide the highest accuracy and precision. The profiles are used to derive a new set of ICESat laser campaign biases and finally, to evaluate several DEMs.