Summary: | Ocean tides influence the flow of marine-terminating glaciers. Observations indicate that the large fortnightly variations in ice flow at Rutford Ice Stream in West Antarctica originate in the floating ice shelf. We show that nonlinear variations in ice shelf buttressing driven by tides can produce such fortnightly variations in ice flow. These nonlinearities in the tidal modulation of buttressing stresses can be caused by asymmetries in the contact stress from migration of the grounding line and bathymetric pinning points beneath the ice shelf. Using a simple viscoelastic model, we demonstrate that a combination of buttressing and hydrostatic stress variations can explain a diverse range of tidal variations in ice shelf flow, including the period, phase and amplitude of flow variations observed at Rutford and Bindschadler Ice Streams. © The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Published online: 04 September 2017. We thank Doug MacAyeal, Kelly Brunt, Hilmar Gudmundsson and Olga Sergienko for helpful conversations during the completion of this work. We also thank Bob Bindschadler and Hilmar Gudmundsson for providing GPS data. Source code and documentation of the models used in this study are available as public repositories on GitHub: https://github.com/aarobel/. AR has been supported by the NOAA Climate & Global Change and Caltech Stanback postdoctoral fellowships during the completion of this work. BM was supported by a NSF Earth Sciences Postdoctoral Fellowship award EAR-1452587. This work was also supported by NSF grant EAR-1453263. Published - tidal_modulation_of_ice_shelf_buttressing_stresses.pdf
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