Lead supervisor: Neil Arnold, Scott Polar Research Institute
Co-supervisor: Ian Willis, Scott Polar Research Institute; Robert Law, University of Bergen; Alison Banwell, CIRES USA
Brief summary:
Use and develop a numerical model to investigate the evolution and impacts of surface lakes on George VI Ice Shelf, Antarctica
Importance of the area of research concerned:
Floating ice shelves around the Antarctic coast act buttress the flow of inland ice, acting as a major control on the ice sheet’s sea level contribution. Over recent decades, a small but growing number of ice shelves have collapsed, often leading to increased flow of the glaciers feeding them, increasing global sea levels. The presence of large numbers of surface meltwater ponds can act as a trigger for this collapse as ponds increase in absorption of solar energy; the weight of the water can flex the ice shelf, leading to fracturing; and winter re-freezing of melt alter the density and strength of the ice. This proposal complements current remote sensing and field-based research on George VI Ice Shelf, Antarctic Peninsula, which has experienced record melt recently. The ice shelf buttresses inland glaciers, which show long term acceleration due to ice shelf thinning, and seasonal velocity variations showing sensitivity to changing forcing. The project will develop and use a numerical model of ice shelf lakes in conjunction with previously collected field data to investigate the impact of ponds on the ice shelf to help assess its potential vulnerability to fracture and collapse.
Project summary :
Use an existing numerical model for the evolution of surface meltwater ponds on ice shelves applying it to George VI Ice Shelf, Antarctic Peninsula. The model will be forced with a combination of in situ and published climate data. Outputs from the model will be compared with remote-sensing-derived estimates of meltwater extent and volume, and in situ data from previous field work consisting of time-lapse camera-derived estimates of meltwater extent, time-dependent 10 m-deep temperature profiles, and 10 m-deep ice cores. Model outputs will be used to assess the impact of melt ponds on the ice shelf mass balance, and the impact on internal ice sheet temperature and density due to infiltration of the meltwater and re-freezing in firn layers below the surface. There may be the potential to use the results in a 3D ice flow model to test the impact of the ponds on seasonal ice flow.
What will the student do?:
The student will apply existing models of ice shelf lakes to George VI Ice Shelf, Antarctic Peninsula. This will involve assessing the model complexity most suited to the location, and may include some model modification/development. The initial application of the model will involve the use of both published gridded climate and in situ climate data for recent years, which will need to be processed by the student into a usable format for the model experiments. The outputs from the model will be validated against existing data from satellite remote sensing, both visible and radar data, and against in situ measurements of time-lapse camera-derived estimates of meltwater extent, time-dependent 10 m-deep temperature profiles, and 10 m-deep ice cores from the ice shelf. After this phase of model validation and assessment, the student will then run the model into the future using a range of current climate prediction models, downscaled as needed. It may also be possible to incorporate the model results on the possible impact of lakes on ice density and rheology into a 3D ice flow model to assess the possible impact on ice flow in the ice shelf, and in the glaciers which feed it.
References - references should provide further reading about the project:
Law, R., Arnold, N., Benedek, C., Tedesco, M., Banwell, A. and Willis, I., 2020. Over-winter persistence of supraglacial lakes on the Greenland Ice Sheet: Results and insights from a new model. Journal of Glaciology, v. 66, p.362-372. doi:10.1017/jog.2020.7
Banwell, A.F., Datta, R.T., Dell, R.L., Moussavi, M., Brucker, L., Picard, G., Shuman, C.A. and Stevens, L.A., 2021. The 32-year record-high surface melt in 2019/2020 on the northern George VI Ice Shelf, Antarctic Peninsula. The Cryosphere, v. 15, p.909-925. doi:10.5194/tc-15-909-2021
Boxall, K., Christie, F.D.W., Willis, I.C., Wuite, J. and Nagler, T., 2022. Seasonal land-ice-flow variability in the Antarctic Peninsula. The Cryosphere, v. 16, p.3907-3932. doi:10.5194/tc-16-3907-2022
Applying
You can find out about applying for this project on the Department of Geography page.