Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime

Drews, Reinhard; Wild, Christian T; Marsh, Oliver J. ORCID:; Rack, Wolfgang; Ehlers, Todd A.; Neckel, Nikals; Helm, Veit. 2021 Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime. Geophysical Research Letters, 48 (20), e2021GL093853. 10, pp.

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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 also oscillate 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.

Item Type: Publication - Article
Digital Object Identifier (DOI):
ISSN: 0094-8276
Additional Keywords: glaciology, ice streams, ice-ocean interactions, ocean tides, surface velocities, geophysics
Date made live: 01 Mar 2021 10:43 +0 (UTC)

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