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Projects

The stability of Greenland’s last remaining ice shelves in a warming climate

Left: icebergs in Sermilik fjord, SE Greenland. Right: basal melt rates of Greenland’s ice tongues (figure from Wilson et al., 2017, Cryosphere). This project will use cutting-edge remote sensing, data science and ocean modeling to understand basal melting of Greenland’s remaining ice tongues, and to assess their stability in a warming climate.

Background

The Greenland Ice Sheet has lost over 4 trillion tonnes of ice since 1992, making Greenland a major contributor to global sea level rise. Yet poor understanding of the physical processes driving ice loss hampers our ability to make future sea level projections. Driven by this need, this project will combine earth observation, advanced analysis and ocean modeling to investigate the vulnerability of Greenland’s last remaining ice shelves to melting by combined atmospheric and oceanic processes.

In Greenland, ice flows from the centre to the edge of the ice sheet, forming ice streams. Most of these ice streams terminate at vertical calving fronts where the ice sheet meets the ocean, but a few large ice streams terminate in vast ice shelves. Greenland has only three remaining ice shelves (figure, right), which are floating and melt into the ocean (‘basal melting’). It is generally assumed that ocean temperature controls melting of the base of these ice shelves, but melting may be enhanced by freshwater draining from beneath the ice shelf (‘subglacial discharge’), setting up an ocean circulation that flushes warm water against the ice. If this is the case, and since subglacial discharge is projected to increase dramatically in northern Greenland over the coming century, it may be the case that subglacial discharge damages the ice shelves more than a warming of the ocean. This project will therefore investigate the sensitivity of basal melting of Greenland’s ice shelves to subglacial discharge in the recent past and over the coming century.

Aims, objectives and methodology

  1. Combine Earth Observation (satellite imagery from e.g. Sentinel, Cryosat) with state-of-the-art processing to estimate ice shelf basal melt rate at high spatial and temporal resolution. Employ advanced data analysis techniques (e.g. machine learning) to understand how subglacial runoff drives spatial and temporal variability in ice shelf basal melting in Greenland.
  2. Develop computer simulations of ocean circulation beneath Greenland’s ice shelves using the Massachussetts Institute of Technology general circulation model (MITgcm), and compare with the satellite observations to build fundamental dynamical understanding of the basal melting process.
  3. Combine the knowledge gained in (1) and (2), together with global climate simulations, to predict basal melt rates over the coming century. Assess the future stability of Greenland’s ice shelves in the context of a warming climate and recent ice shelf collapses.

Training

Through participating in this project, the student will gain advanced skills in earth observation and in cutting-edge computational and numerical techniques. You will become a valued member of the world-class Cryosphere research group at the University of Edinburgh. The supervisory team are world experts in their respective specialities, ensuring that the student will be well integrated into the international science community. You will be encouraged to attend and present your work at national and international conferences, and will be supported to publish your findings in leading academic journals. The student will be able to spend an extended period of time working with co-supervisor Straneo at Scripps Institution of Oceanography in San Diego, providing an exciting opportunity to discuss their analysis with interdisciplinary scientists in the world-leading Scripps Polar Centre. The student will have further opportunities for multi-disciplinary training through, for example, summer schools in Greenland and through participating in supervisors’ Arctic fieldwork.

Requirements

This project is well-suited to an enthusiastic candidate with an interest in working in rigorous, international, fast-moving climate research that can have a real impact on high-level policy (for example through the IPCC assessment reports). The ideal candidate will have a strong quantitative and analytical background as could be demonstrated by, for example, an undergraduate and/or masters degree in physics, engineering, earth sciences, physical geography, mathematics or computer science. The student will run sophisticated numerical models and analyse complex datasets, so that prior experience of scientific computing and writing code may be an advantage. An ability to communicate complex ideas in a simple fashion will also be valuable. A specific background in glaciology or climate sciences is not required.

The student will be based and registered at the University of Edinburgh. Applicants are encouraged to contact the primary supervisor to discuss the project.

Further reading

  1. Some media articles on Greenland’s ice shelves and ice-ocean interactions
  2. Straneo & Heimbach, 2013, Nature: North Atlantic warming and the retreat of Greenland’s outlet glaciers
  3. Wilson et al., 2007, CryosphereSatellite-derived submarine melt rates and mass balance (2011–2015) for Greenland’s largest remaining ice tongues
  4. Washam et al., 2019, J. GlaciologySummer surface melt thins Petermann Gletscher Ice Shelf by enhancing channelized basal melt
  5. Lindeman et al., 2020, JGR Oceans: Ocean circulation and variability beneath Nioghalvfjerdsbræ (79 North Glacier) ice tongue
  6. Schaffer et al., 2020, Nature GeoscienceBathymetry constrains ocean heat supply to Greenland’s largest glacier tongue
  7. Supervisors’ websites: Donald Slater, Anna Hogg, Noel Gourmelen, Paul Holland, Fiamma Straneo