About the Project
One of the most intriguing glacier observations of the last decade or so has been that the velocity of many large glaciers varies substantially from its long-term mean due to tidal variation in the zone where the glaciers begin to flow – their grounding zone (Anandakrishnan et al. 2003; Gudmundsson et al., 2006, 2011; Winberry et al., 2011; Rosier et al., 2015). Such changes in motion have been observed using GPS on large West Antarctic glaciers, with the changes propagating tens of kilometres upstream. Combined with modelling, they provide unique insights into the interaction of the ice and its bed, the role of subglacial water, and the sensitivity of glaciers to modest changes in forcing (e.g., Rosier et al., 2015).
In parallel the floating extension of entire glacier systems, the ice shelves, have also been observed to experience tidal modulation of their flow (Doake et al., 2002; King et al. 2011; Makinson et al., 2011). These include the large Ross and Ronne ice shelves, fed by large ice streams tens of kilometres wide, alongside the smaller Larsen C Ice Shelf (King et al., 2011) fed by relatively small glaciers by Antarctic standards. The precise link between the modulation of flow of grounded and floating ice is yet to be fully established.
The Larsen C Ice Shelf system’s response to tidal forcing is little studied to date, in particular the upstream glaciers, and this PhD will focus on modelling the response of the Larsen C system to tidal forcing in an attempt to understand the characteristics of the glaciers feeding the ice shelf and their sensitivity to changes in forcing in their grounding zone.
Keywords: Antarctica, modelling, ocean, ice, tides
Funding Notes
Australian/New Zealand students are eligible for Australian Postgraduate Awards which cover fees and living expenses. Highly qualified applicants may be eligible for Elite (top-up) Scholarships, worth $32,000 tax free per annum, a free laptop and pre-application trip to check out Hobart and the University of Tasmania.
Funding for overseas students is available on a competitive basis for students with a strong track record (journal publication, University Medal, MSc in English, etc.). **Please only make contact if you have such a strong record.**
References
Anandakrishnan, S., D.E. Voigt, R.B. Alley and M.A. King 2003. Ice stream D flow speed is strongly modulated by the tide beneath the Ross Ice Shelf. Geophysical Research Letters, 30(7): 1361, doi:10.1029/2002GL016329.
Doake, C.S.M., H.F.J. Corr, K.W. Nicholls, A. Gaffikin, A. Jenkins, W.I. Bertiger and M.A. King 2002. Tide-induced lateral movement of Brunt Ice Shelf, Antarctica. Geophysical Research Letters, 29(8), doi:10.1029/2001GL014606.
King, M.A., K. Makinson and G.H. Gudmundsson 2011. Nonlinear interaction between ocean tides and the Larsen C Ice Shelf system. Geophysical Research Letters, 38: L08501, doi:10.1029/2011GL046680.
Gudmundsson, G.H. 2006. Fortnightly variations in the flow velocity of Rutford Ice Stream, West Antarctica. Nature, 444(7122): 1063-1064, doi:10.1038/nature05430.
Gudmundsson, G.H. 2011. Ice-stream response to ocean tides and the form of the basal sliding law. The Cryosphere, 5(1): 259-270, doi:10.5194/tc-5-259-2011.
Makinson, K., M.A. King, K.W. Nicholls and G.H. Gudmundsson 2012. Diurnal and semidiurnal tide-induced lateral movement of Ronne Ice Shelf, Antarctica. Geophysical Research Letters, in press, doi:10.1029/2012GL051636.
Rosier, S.H.R., G.H. Gudmundsson and J.A.M. Green 2015. Temporal variations in the flow of a large Antarctic ice stream controlled by tidally induced changes in the subglacial water system. The Cryosphere, 9(4): 1649-1661, doi:10.5194/tc-9-1649-2015.
Winberry, J.P., S. Anandakrishnan, D.A. Wiens, R.B. Alley and K. Christianson 2011. Dynamics of stick-slip motion, Whillans Ice Stream, Antarctica. Earth and Planetary Science Letters, 305(3-4): 283-289, doi:10.1016/j.epsl.2011.02.052.