skip to primary navigationskip to content
 

C419: The response of Antarctic ice streams to tidal forcing (Lead Supervisor: Jerome Neufeld, DAMTP)

gudmundson

Supervisors: Jerome Neufeld (DAMTP), Brent Minchew (MIT), Hilmar Gudmundsson (British Antarctic Survey) and Duncan Hewitt (DAMTP)

Importance of the area of research:

The transport of ice from the interior of Antarctica to the oceans is dominated by the flux through several fast-flowing ice streams whose behaviour is greatly influenced by the conditions at their base and at grounding points along the ice-ocean interface. The response of the ice velocity to changing basal conditions presents a key challenge for predicting future behaviour in a changing climate.  Recent observations have shown that the motion of ice streams is sensitive, over 10s of kilometres, to ocean tides (Gudmundsson 2006, Minchew et al. 2017) suggesting a coupling between the flow of glacial ice, shear heating at lateral margins, and pore pressure changes in subglacial sediment.  This project aims to understand the nonlinear coupling of viscous ice with the pressure-dependent rheology of the subglacial till through the use of highly resolved measurements of glacial motion, both spatially and temporally, in response to the tidal forcing.

Project summary:

This project combines analysis of satellite and GPS observations of the variability of ice stream motion in response to tidal forcing at a number of key Antarctic sites, along with simplified models of the motion of glacial ice over a poro-elastic subglacial till (Hewitt et al, sub judice).  This combination of simple physical models and state-of-the-art observations combines two rapidly evolving scientific fields, poromechanics and remote sensing, to address fundamental questions in ice sheet evolution related to the mechanics of fluid-saturated subglacial sediments.

What the student will do:

The student will develop a series of simple mathematical models of glacial motion in confined ice streams flowing over poro-elastic subglacial sediment and the variation in sliding velocity in response to periodic oceanic forcing. The student will also undertake analogue laboratory experiments and detailed numerical simulations, against which these simplified models will be tested.  The results of these mathematical models will be used to interrogate new velocity data from Rutford Ice Stream and 4 other ice streams that flow into the Filchner-Ronne Ice Sheet in Antarctica. In these areas, the phase and amplitude of the velocity response to ocean tides has been and will continue to be measured at numerous locations using GPS stations and satellite remote sensing. The spatial coverage of these observations allows us to measure the propagation of variations in flow velocity at geophysically relevant spatial scales.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Gudmundsson, G.H. (2006) Fortnightly variations in the flow velocity of Rutford Ice Stream, West Antarctica. Nature. 444(7122), 1063-1064.

Minchew, B.M. et al. (2017) Tidally induced variation in vertical and horizontal motion on Rutford Ice Stream, West Antarctica, inferred from remotely sensed observations. J. Geophys. Res. 122(1), 167-190.

Hewitt, D.R., Chini, G.P., Neufeld, J.A. (sub judice) Subglacial drainage and propagation through poroelastic till. J. Fluid Mech (available on request)

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

Filed under: