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Grounding-zone flow variability of Priestley Glacier, Antarctica, in a diurnal tidal regime
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  • Reinhard Drews,
  • Christian T. Wild,
  • Oliver J. Marsh,
  • Wolfgang Rack,
  • Todd Ehlers,
  • Niklas Neckel,
  • Veit Helm
Reinhard Drews
Department of Geosciences, University of Tübingen

Corresponding Author:reinhard.drews@uni-tuebingen.de

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Christian T. Wild
Oregon State University
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Oliver J. Marsh
British Antarctic Survey
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Wolfgang Rack
University of Canterbury, NZ
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Todd Ehlers
University of Tubingen
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Niklas Neckel
Alfred Wegener Institute for Polar and Marine Research
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Veit Helm
Alfred Wegener Institute
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Dynamics of polar outlet glaciers vary with ocean tides, providing a natural laboratory to understand basal processes and ice rheology. We apply Terrestrial Radar Interferometry to close the spatiotemporal gap between GNSS and satellite observations. Three-hour flowfields collected over an eight day period at Priestley Glacier, Antarctica, validate and provide the spatial context for concurrent GNSS measurements. Ice flow is fastest during falling tides and slowest during rising tides. Principal components of the timeseries prove upstream propagation of tidal signatures $>$ 10 km away from the grounding line. Hourly, cm-scale horizontal and vertical flexure patterns occur $>$6 km upstream of the grounding line. Vertical uplift upstream of the grounding line is consistent with ephemeral re-grounding during low-tide impacting grounding-zone stability. Taken together, these observations identify tidal imprints on ice-stream dynamics on new temporal and spatial scales providing constraints for models designed to isolate dominating processes in ice-stream mechanics.
28 Oct 2021Published in Geophysical Research Letters volume 48 issue 20. 10.1029/2021GL093853