Articles | Volume 8, issue 6
The Cryosphere, 8, 2119–2134, 2014
The Cryosphere, 8, 2119–2134, 2014

Research article 24 Nov 2014

Research article | 24 Nov 2014

Sensitivity of the Weddell Sea sector ice streams to sub-shelf melting and surface accumulation

A. P. Wright1, A. M. Le Brocq1, S. L. Cornford2, R. G. Bingham3, H. F. J. Corr4, F. Ferraccioli4, T. A. Jordan4, A. J. Payne2, D. M. Rippin5, N. Ross6, and M. J. Siegert7 A. P. Wright et al.
  • 1Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK
  • 2Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
  • 3School of Geosciences, University of Edinburgh, Edinburgh EH8 9XP, UK
  • 4British Antarctic Survey, Madingley Road, High Cross, Cambridge, Cambridgeshire CB3 0ET, UK
  • 5Environment Department, University of York, Heslington, York YO10 5DD, UK
  • 6School of Geography, Politics and Sociology, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
  • 7Grantham Institute and Department of Earth Science and Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK

Abstract. A recent ocean modelling study indicates that possible changes in circulation may bring warm deep-ocean water into direct contact with the grounding lines of the Filchner–Ronne ice streams, suggesting the potential for future ice losses from this sector equivalent to ~0.3 m of sea-level rise. Significant advancements have been made in our knowledge of both the basal topography and ice velocity in the Weddell Sea sector, and the ability to accurately model marine ice sheet dynamics, thus enabling an assessment to be made of the relative sensitivities of the diverse collection of ice streams feeding the Filchner–Ronne Ice Shelf. Here we use the BISICLES ice sheet model, which employs adaptive-mesh refinement to resolve grounding line dynamics, to carry out such an assessment. The impact of realistic perturbations to the surface and sub-shelf mass balance forcing fields from our 2000-year "reference" model run indicate that both the Institute and Möller ice streams are highly sensitive to changes in basal melting either near to their respective grounding lines, or in the region of the ice rises within the Filchner–Ronne Ice Shelf. These same perturbations have little impact, however, on the Rutford, Carlson or Foundation ice streams, while the Evans Ice Stream is found to enter a phase of unstable retreat only after melt at its grounding line has increased by 50% of likely present-day values.