Differential Interferograms of the grounding zone at Priestley Glacier, Antarctica, aquired with Terrestrial Radar Interferometry

• Main Authors: Drews, Reinhard, Wild, Christian T, Marsh, Oliver, Rack, Wolfgang, Ehlers, Todd A, Neckel, Niklas, Helm, Veit
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: Antarctica; Differential Interferometry; ERA-PLANET; flowfields; grounding zone dynamics; Ice dynamics; Priestley_Glacier; Terrestrial Radar Interferometry; The European network for observing our changing planet; Priestley; Priestley Glacier; Antarc*; Ice Shelf; Ice Shelves
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.935707; https://doi.org/10.1594/PANGAEA.935707

These data were aquired with a Terrestrial Radar Interferometer overlooking the grounding zone of Priestley Glacier, Antarctica. The time series contains differential interferograms with a 12h temporal baseline covering an approximately 8 day period in November 2018. 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.