Antarctic Grounding Line Migration from ICESat-2 Altimetry (part of the SENSE Centre for Doctoral Training)

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. The project is offered as part of the SENSE Centre for Doctoral Training (CDT) initiative on Earth Observation (see https://eo-cdt.org/). In this PhD, you will work closely with world-leading Earth observation experts to better understand change on the Antarctic Ice Sheet. Whilst it is impossible to make a direct observation of the ice-bed interface beneath the ice sheet surface, the grounding line position which marks the boundary between the grounded ice sheet and floating ice shelves can be monitored using satellite remote sensing by measuring vertical displacement of the floating ice shelf caused by ocean tides. This project will make use of ICESat-2 laser altimetry data to map present day change in the grounding line position, monitor stability of the most vulnerable sectors of the Antarctic ice sheet, and investigate how migration driven by ocean tides impacts ice behaviour. The ICESat-2 satellite launched in 2018, and provides unprecedented spatial resolution and coverage of Antarctica. Its laser altimeter is split into six beams transmitting at 10 kHz, which allows a pulse of light to hit the ice sheet surface every 70 cm. The satellite has been specifically designed to allow accurate measurement of cross-track slopes in regions of steep topography (i.e. near grounding lines). These altimetry measurements will be complimented by synthetic aperture radar interferometric measurements of the grounding line location from other satellites including Sentinel-1 and TerraSAR-X.

Harnessing the capability of both historical and new satellite missions, and focusing on one of the most sensitive parts of the ice sheet, the project will provide new insight into fundamental processes driving velocity variation in Antarctic ice shelves and allow current rates of grounding line retreat to be observed with higher confidence.

What will the student do?

The student will analyze new laser altimetry data from ICESat-2 spanning the period from 2018 onwards, building on grounding line mapping studies from previous altimeters (ICESat and Cryosat-2). Radar interferometry and ICESat (2003-2009) will be used to identify long-term change in the grounding line location, while repeat ICESat-2 measurements will be used to identify short-term variability. Horizontal movement of the grounding line will be correlated with ocean tide models to identify how grounding line migration is related to tidal amplitude, local ice properties and bed slope.

We are looking for a highly motivated candidate with strong computing skills and a background in natural/physical sciences or remote sensing. All the students will receive intensive training (12 weeks) in advanced Earth Observation and data analytical techniques for the first year (https://eo-cdt.org/programme/).

The student will be based in BAS, Cambridge, but will be registered for their PhD at the University of Leeds, and will spend physical time twice a year in Leeds, as well as taking part in training in Edinburgh, Leeds and Southampton as part of the SENSE cohort.

This PhD is part of the NERC and UK Space Agency funded Centre for Doctoral Training "SENSE": the Centre for Satellite Data in Environmental Science. SENSE will train 50 PhD students to tackle cross-disciplinary environmental problems by applying the latest data science techniques to satellite data. All our students will receive extensive training on satellite data and AI/Machine Learning, as well as attending a field course on drones, and residential courses hosted by the Satellite Applications Catapult (Harwell), and ESA (Rome). All students will experience extensive training on professional skills, including spending 3 months on an industry placement. See http://www.eo-cdt.org