GNSS Data collected at Priestley Glacier November 2018

• Main Authors: Drews, Reinhard, Wild, Christian T, Marsh, Oliver, Rack, Wolfgang, Ehlers, Todd A, Neckel, Niklas, Helm, Veit
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2021
• Subjects: Antarctica; ERA-PLANET; GNSS; GPS; Grounding Line; The European network for observing our changing planet; Antarc*; Ice Shelf; Ice Shelves; Priestley Glacier
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.936090; https://doi.org/10.1594/PANGAEA.936090

This is GNSS data of four stations covering the grounding zone of Priestley Glacier Antarctica. Tidal modulation of ice streams and their adjacent ice shelves is a real-world experiment to understand ice-dynamic processes. We observe the dynamics of Priestley Glacier, Antarctica, using Terrestrial Radar Interferometry (TRI) and GNSS. Ocean tides are predominantly diurnal but horizontal GNSS displacements oscillate also semi-diurnally. The oscillations are strongest in the ice shelf and tidal signatures decay near-linearly in the TRI data over >10 km upstream of the grounding line. Tidal flexing is observed >6 km upstream of the grounding line including cm-scale uplift. Tidal grounding line migration is small and <40 % of the ice thickness. The frequency doubling of horizontal displacements relative to the ocean tides is consistent with variable ice-shelf buttressing demonstrated with a visco-elastic Maxwell model. Taken together, this supports previously hypothesized flexural ice softening in the grounding-zone through tides and offers new observational constraints for the role of ice rheology in ice-shelf buttressing.