Mass loss from the Antarctic Ice Sheet is the largest uncertainty in current sea level rise projections and this uncertainty is largely related to the response of ice shelves. Ice shelves are the gatekeepers of Antarctica as they buttress the contribution of grounded ice to sea level rise. Although several processes have been identified that are key for future ice shelf instability and retreat, assessing how much, how fast ice shelf instability will contribute to future sea level rise remains a major uncertainty. This uncertainty is mainly the result of our limited quantitative understanding of many of the processes that control ice shelf instability. One of these processes is hydrofracturing as a result of ponding meltwater.
Surface meltwater and melt-albedo feedbacks at the surface of ice shelves are crucial drivers for ice shelf instability through hydrofracturing with important potential impacts as surface melt is projected to increase strongly in the coming century. However, to assess this impact we need improved models that better parameterize surface melt, the associated meltwater hydrology and their impact on hydrofracturing.
The objective of PhD project therefore is to develop and provide novel high-resolution remote sensing observations of surface conditions related to melt to better understand how, where, and how much surface meltwater is formed and where it goes. Within the project you will first combine various remote sensing data sets (optical, (in)SAR, scatterometers) related to melt, albedo and hydrology to get high-resolution estimates of melt and hydrology across all Antarctic ice shelves. Second, you will run offline models (snowmodels, surface energy models, hydrological models) to determine the relative importance of the atmospheric drivers (e.g. warming, changes in foehn/katabatic winds), hydrological conditions and the feedback processes (e.g. melt-albedo feedback) on the satellite observed melt.
During your project, you will work in close collaboration with remote sensing and modeling experts at Delft University of Technology and the Institute for Marine and Atmospheric research Utrecht (IMAU). Your results will be used to validate and calibrate surface melt models over Antarctica and eventually improve our projections of future ice shelf stability.
This position is part of the HiRISE project, a collaboration between researchers at Utrecht University, Delft University of Technology, the Netherlands Royal Meteorological Institute (KNMI), Royal Netherlands Institute for Sea Research (NIOZ) and Université Libre de Bruxelles, and funded by the Netherlands Orgsanisation for Scientific Research (NWO). The project combines field measurements, satellite data and climate models to chart the current state of Antarctica’s ice shelves with high resolution and accuracy and reduce the uncertainty in projections of sea level rise. The HiRISE team will eventually consist of four PhD candidates, four postdocs and one technician. During the project, you will spend part of your time at one of the collaborating institutes and actively exchange your results, ideas and plans during regular meetings with the other team members.
We aim to start the project on 1 Dec 2020. Your application should include a detailed CV, the abstract of your MSc thesis, at least two references, and a letter of motivation in a single PDF file.