Ocean forcing of Filchner Ronne Ice Shelf
Lead supervisor: Dr Peter Davis
Location: British Antarctic Survey, Cambridge
Duration: 8 weeks
Suitable undergraduate degrees: Physics, Oceanography, Maths, Physical Geography, Environmental Science. Experience in using MatLab/Python for data analysis is essential.
The relatively unknown behaviour of the Antarctic ice sheet in a warming world contributes the greatest uncertainty to 21st century sea-level projections. Antarctica’s evolution is largely controlled by the floating ice shelves that form at its seaward margin, which restrict the flow of grounded ice into the ocean. Over recent decades, ocean-induced ice shelf thinning through elevated basal melting has driven increased mass loss from the Antarctic ice sheet and caused sea levels to rise. For the West Antarctic Ice Sheet, ocean-driven basal melting may already have tipped the region into a state of rapid and irreversible ice loss that may ultimately result in the collapse of the entire ice sheet. Such a scenario would raise global sea-level by 2-3 m over the coming centuries, with profound consequences for humanity. Understanding the ocean forcing of Antarctic ice shelves is therefore critical for protecting society and reducing uncertainty in 21st century sea level projections.
Filchner Ronne Ice Shelf (FRIS) is the largest ice shelf by volume in Antarctica. Loss of ice due to basal melting beneath FRIS is currently small, however models indicate that FRIS is vulnerable to warm-water inflows and it may enter of state of significantly enhanced basal melting by 2100. Exploring the dynamics that control the source and fate of oceanic heat that enters the FRIS cavity is therefore essential. In this project we will use a combination of oceanographic and basal melt rate time series to explore:
- How ocean variability controls the rate of ice shelf basal melting beneath FRIS, and
- Investigate the inflow of oceanic heat into the FRIS cavity.
We will start by comparing a time series of basal melt rate measured by surface-based radar with concurrent measurements of temperature, salinity and flow speed taken through a hot-water drilled borehole. We will investigate how variability in the basal melt rate is controlled by variability in the ocean properties, exploring the transitions between periods of basal melting and basal freezing. As the project develops we will work with more challenging datasets, examining variability in the inflow of warm water beneath FRIS. By exploring these processes in detail, we will build a better understanding of how the behaviour of FRIS is likely to change over the 21st century.