Significant uncertainty exists in predictions of future sea level rise from Antarctica. This uncertainty partly arises from our lack of understanding of the ice-ocean processes that melt the ice shelves around the continent’s margin. In this project we will develop a pan-Antarctic atlas of ocean mixing and vertical heat fluxes in these critical regions.
Antarctic ice shelves – the floating extensions of the Antarctic ice sheet – play a critical role in controlling Antarctica’s contribution to future sea level rise by restraining the seaward flow of grounded ice from the continent’s interior. Over recent decades, the rate at which ice shelves in key sectors of Antarctica are being melted from below by the ocean has accelerated, increasing the flow of grounded ice into the ocean and contributing to sea level rise. The magnitude of ice shelf basal melting is controlled by how quickly turbulent mixing transfers heat and salt to the ice base. Direct measurements of this turbulent mixing are sparse, hampering our ability to understand the important ice-ocean interactions and processes that drive ice shelf melting. This project will seek to exploit a range of existing datasets from beneath Antarctic ice shelves to generate the first pan-Antarctic atlas of sub-ice shelf mixing rates. We will seek to answer:
- How do the rates of vertical turbulent mixing vary in space and time beneath different Antarctic ice shelves?
- What are the key controls on this variability, including the role of large-scale ocean forcing (e.g. tides, stratification) and ice shelf topography?
- How is the space-time variability in mixing and vertical heat fluxes related to space-time variability in basal melting?
The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at the British Antarctic Survey. Specific training will
- Training in the processing and interpretation of sub-ice shelf temperature and salinity and velocity data, and in time series analysis techniques.
- Training in finescale mixing parameterisations and calculating the rate of vertical mixing beneath Antarctic ice shelves from temperature, salinity and velocity profiles and time series.
- Training in the processing and interpretation of microstructure data.
- The potential opportunity to participate in polar research cruises/fieldwork in the Southern Ocean and on Antarctic ice shelves, giving experience in the collection and processing of a variety of different physical oceanographic data. Note this is not required for successful completion of the PhD as the data are already collected.
Davis, PED and Nicholls, KW (2019). Turbulence observations beneath Larsen C ice shelf, Antarctica. Journal of Geophysical Research: Oceans 124 (8), 5529-5550
Brearley, JA, Meredith, MP, Naveira Garabato, AC, Venables, HJ, Inall, ME (2017) Controls on turbulent mixing on the West Antarctic Peninsula shelf. Deep Sea Research II: Topical Studies in Oceanography, 139. 18-30
Stevens, C, Hulbe, C, Brewer, M, Stewart, C, Robinson, N, Ohneiser, C et al. (2020). Ocean mixing and heat transport processes observed under the Ross Ice Shelf control its basal melting. Proceedings of the National Academy of Sciences 117 (29), 16799-16804