Do certain wind regimes promote surface melt over George VI Ice shelf?
Lead supervisor: Dr Amelie Kirchgaessner
Location: British Antarctic Survey, Cambridge
Duration: 6 weeks
Suitable undergraduate degrees: Engineering, Physics, Mathematics, Computing
The floating ice shelves around Antarctica provide a buffer against rapid ice flow from the continent’s interior to the ocean. If that buffer is reduced or removed, the ice flow towards the ocean will accelerate. Unlike the ice shelves themselves, this ice flow will contribute to global sea level rise. It is therefore important to understand the controls on ice shelf stability, to assess and predict a possible future ice shelf collapse. Evidence shows that one source of ice shelf instability comes from surface melting and the movement of the meltwater. This project contributes to research of the supervisor into the atmospheric drivers of surface melt over ice shelves around the Antarctic Peninsula.
Adiabatic warming in the lee of mountains (Föhn) has been found to be the key driver behind surface melt over the Larsen Ice Shelf. Orographic conditions around GVIIS are similarly conducive to the occurrence of Föhn winds. The orography, though, is also well suited to channel warm northerly air flow over the ice shelf, which should have similar potential to induce surface melt. High resolution simulations of the atmosphere and the surface mass balance in the area of George VI ice Shelf (GVIIS) will be used to investigate the atmospheric drivers of such surface melt.
The key steps and questions of this project are the following:
- Identify events or periods of increased surface melt in the data set.
- Investigate the atmospheric flow and wind regime leading up and during these melt events.
- Do Föhn winds or channel flow play an important role leading to these melt situations?
- If this is the case, is one a dominant driver for melt?
The student will use existing simulations of the regional atmospheric climate model RACMO2 from 1979 to 2016.
Model output of radiative and turbulent fluxes at and near the surface will be used to identify melt events in the local surface energy balance. Pressure and wind fields together with potential temperature and humidity fields will be used to identify the wind regime.
Some of the steps can be addressed by adapting computer code that already exists within the team, others will give the student opportunity to practice or develop their programming skills.
The prospective student should be doing a numerate degree and have basic physics knowledge. Knowledge of basic meteorology, data processing and statistical analysis is desirable. They should have some programming experience.
van Wessem, J. M., van de Berg, W. J., Noël, B. P. Y., van Meijgaard, E., Amory, C., Birnbaum, G., Jakobs, C. L., Krüger, K., Lenaerts, J. T. M., Lhermitte, S., Ligtenberg, S. R. M., Medley, B., Reijmer, C. H., van Tricht, K., Trusel, L. D., van Ulft, L. H., Wouters, B., Wuite, J., and van den Broeke, M. R.: Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 2: Antarctica (1979–2016), The Cryosphere, 12, 1479–1498, https://doi.org/10.5194/tc-12-1479-2018, 2018.