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Strong tidal variations in ice flow observed across the entire Ronne Ice Shelf and adjoining ice streams

Citation

Rosier, SHR and Gudmundsson, GH and King, MA and Nicholls, KW and Makinson, K and Corr, HFJ, Strong tidal variations in ice flow observed across the entire Ronne Ice Shelf and adjoining ice streams, Earth System Science Data, 9 pp. 849-860. ISSN 1866-3508 (2017) [Refereed Article]


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DOI: doi:10.5194/essd-9-849-2017

Abstract

We present a compilation of GPS time series, including those for previously unpublished sites, showing that flow across the entire Ronne Ice Shelf and its adjoining ice streams is strongly affected by ocean tides. Previous observations have shown strong horizontal diurnal and semidiurnal motion of the ice shelf, and surface flow speeds of Rutford Ice Stream (RIS) are known to vary with a fortnightly (Msf) periodicity. Our new data set shows that the Msf flow modulation, first observed on RIS, is also found on Evans, Talutis, Institute, and Foundation ice streams, i.e. on all ice streams for which data are available. The amplitude of the Msf signal increases downstream of grounding lines, reaching up to 20 % of mean flow speeds where ice streams feed into the main ice shelf. Upstream of ice stream grounding lines, decay length scales are relatively uniform for all ice streams but the speed at which the Msf signal propagates upstream shows more variation. Observations and modelling of tidal variations in ice flow can help constrain crucial parameters that determine the rate and extent of potential ice mass loss from Antarctica. Given that the Msf modulation in ice flow is readily observed across the entire region at distances of up to 80 km upstream of grounding lines, but is not completely reproduced in any existing numerical model, this new data set suggests a pressing need to identify the missing processes responsible for its generation and propagation. The new GPS data set is publicly available through the UK Polar Data Centre at http://doi.org/10.5285/4fe11286-0e53-4a03-854c-a79a44d1e356.

Item Details

Item Type:Refereed Article
Keywords:ice shelf, tidal modulation of flow, tides, velocity
Research Division:Engineering
Research Group:Geomatic Engineering
Research Field:Geodesy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:King, MA (Professor Matt King)
ID Code:122667
Year Published:2017
Funding Support:Australian Research Council (FT110100207)
Deposited By:Geography and Spatial Science
Deposited On:2017-11-22
Last Modified:2017-12-01
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