Inferring consistent coordinate time series from reprocessed GNSS data (GIANT-REGAIN) to probe the solid Earth and its interactions in Antarctica

For almost three decades, geodetic GNSS measurements have been used to infer bedrock displacement in Antarctica. However, until now Antarctic-wide studies have only been able to make use of a limited number of GNSS stations and have also been limited in time. Within the project GIANT-REGAIN (Geodynamics In ANTarctica based on REprocessing GNSS DAta INitiative), endorsed by the SCAR Expert Group GIANT and the SCAR Scientific Program INSTANT, for the first time geodetic GNSS data have been compiled for as many Antarctic bedrock stations as possible, covering the period from 1995 to 2021. The recordings include permanent and episodic observations at more than 270 sites. In order to provide a consistent and reliable analysis of these data, four processing centres have joined forces to reprocess the data. The background and the most important issues of the reprocessing will be reported. We will discuss the resulting coordinate time series in terms of their reliability and uncertainty, and their usability to infer displacement rates for subsequent analyses in Antarctic geodynamics, especially GIA. Thus, these coordinate time series will allow to investigate the Antarctic bedrock displacement pattern in much more detail than before. Inferring displacement rates will enable us to study deformation processes on different time and spatial scales, governed by the rheological properties of the Earth’s interior. This includes the response of the solid Earth on short time scales due to a weak upper mantle or the variability of the Antarctic ice sheet in the Holocene which may lead to present-day subsidence.

The results of GIANT-REGAIN are discussed in a paper published in Earth System Science Data, and the data products are archived at PANGAEA and, thus, publicly accessible.