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Projects

Ice Sheet – ocean interactions: Using satellite data to understand ice dynamic change

Over the last 25-years, Ice sheets in Greenland and Antarctica have raised the global sea level by 1.8 cm since the 1990’s, and are matching the Intergovernmental Panel on Climate Change’s worst-case climate warming scenarios. In Greenland, mass loss from the ice sheet is dominated by high rates of surface melt during the summer, with individual extreme years having a major impact on the total sea level contribution. Satellite observations have shown that ice loss from Antarctica is dominated by dynamic imbalance in the low-lying, marine-based sectors of West Antarctica; where glaciers in the Amundsen Sea Sector have thinned, accelerated, and grounding-lines have retreated since the 1940’s. Ice speedup in West Antarctica is driven by incursions of warm modified Circum-polar Deep Water (mCDW) melting the floating ice, with the interannual and long-term variability of ocean temperatures linked to atmospheric forcing associated with the El Nino-Southern Oscillation (ENSO). The ice sheet contribution to the global sea level budget remains the greatest uncertainty in future projections of sea level rise, driven in part by positive feedbacks such as the Marine Ice Sheet Instability (MISI), and with the most extreme scenarios only possible through the onset of Marine Ice Cliff Instability (MICI). Both long term and emerging new dynamic signals must be accurately measured in order to better understand how ice sheets will change in the future.

Project summary:

This project offers an exciting opportunity to work at the interface of climate and space science, making an important contribution to international efforts to study the effects and impact of climate change. You will work closely with world-leading Earth observation experts to better understand change on the Antarctic Ice Sheet, and oceanographers who measure how the ocean impacts on ice melt. Satellite Earth Observation has revolutionized our understanding of the remote and inaccessible Polar Regions. Without this critical resource we would have a far less complete understanding of which regions are changing, the timing and pace at which events occur, and what physical mechanisms are responsible for driving change. During the last 30-years, individual ice streams in Antarctica such as Pine Island Glacier, have increased in speed by over 42% since the early 1990’s, and are now known to be dynamically imbalanced. However, despite a clear long-term trend for increasing ice velocity in many regions, the observed speed up has not been constant through time, and multiple years with no significant change have also been observed. In this PhD based at the University of Leeds, you will work closely with world-leading experts in satellite observations, Polar oceanography, and advanced computer techniques, to better understand the ice dynamics of the Antarctic Ice Sheet. Through supervision by Dr Hogg, you will use satellite observations to measure ice speed and then the mass balance of the Antarctic and Greenland Ice sheets, quantifying the ice sheet sea level contribution over the last 30-years. Synthetic Aperture Radar (SAR) data, from Earth observation satellites including ERS-1/2, TerraSAR-X and Sentinel-1, will be used to track changes in ice speed In Antarctica, using intensity feature tracking and interferometry. Through co-supervision by Dr Dutrieux at the British Antarctic Survey (BAS) your satellite observations will be combined with observations of ocean temperature, collected using seal tags, moorings, and Automatic Underwater Vehicles, in order to better understand the physical mechanisms driving this change. Through co-supervision by Dr Wang at University of Leeds, you will pioneer the use of advanced computer techniques, such as Artificial Intelligence, to determine the significance of observed change, and to correlate changes in ice flow with ocean temperature measurements. Your supervision by Dr Jenkins will lead to application of a plume model that will help investigate the distribution of regions of extreme melt near the grounding line.

What will the student do?

During your PhD you will lead at least three journal papers on these important science topics. The PhD will be based in the School of Earth and Environment at the University of Leeds, and you will therefore have valuable opportunities to work closely with co-supervisors at BAS, and European collaborators through the projects affiliation with the ESA Polar+ Ice Shelves research project that is already funded. The successful applicant will have access to a broad spectrum of specialist training in Earth Observation and glaciology, in addition to the extensive University of Leeds workshops on a range of topics, including scientific programming through to managing your degree. You may have the option to undertake a Polar field campaign during this PhD. Applicants will hold good first degree (first or high 2.1) or Masters degree in physics, maths, Earth science, climate science, computer science, Earth observation or a related discipline. Expertise in computer programming, while not required, will be a valuable asset. We welcome applications from a wide range of backgrounds, including those with non-traditional qualifications or from industry – please contact us to have a chat about your suitability for the programme.