Grounding‐Zone Flow Variability of Priestley Glacier, Antarctica, in a Diurnal Tidal Regime
Abstract 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 horizonta...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2021-10-01
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| Series: | Geophysical Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2021GL093853 |
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| Summary: | Abstract 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. |
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| ISSN: | 0094-8276 1944-8007 |