Tidal modulation of ice shelf buttressing stresses

• Published in: Annals of Glaciology
• Main Authors: Alexander A. Robel, Victor C. Tsai, Brent Minchew, Mark Simons
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2017
• Subjects: Antarctic glaciology; ice dynamics; ice/ocean interactions; ice-sheet modelling; ice shelves; Meteorology. Climatology; QC851-999; Antarctic; West Antarctica; Rutford; Rutford Ice Stream; Annals of Glaciology; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://doi.org/10.1017/aog.2017.22; https://doaj.org/article/26ffec4925954ccdb2ce547dfc96da6d

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.