PhD Position Remote Sensing of Ice Shelf Firn Processes

Updated: 2 months ago
Job Type: Temporary
Deadline: 16 Aug 2020

Antarctic mass loss is the largest source of uncertainty in current sea level rise projections. Ice shelves are the floating gatekeepers that surround 75% of Antarctica’s coastline and buttress the contribution of grounded ice to sea level rise. Hence, ice shelf instability plays a key role in this uncertainty. The health of an ice shelves is, among other things, dependent on the firn layer on their surfaces, as this layer of compacted snow has the capacity to store meltwater. Once saturated, however, the remaining water will pool in surface features which may cause hydrofracturing and the eventual collapse of the entire ice shelf. A good understanding of subsurface processes in the firn layer, such as refreezing and meltwater retention, are therefore key to improving our understanding of current and future ice shelf stability. Unfortunately, field measurements of these processes are difficult to obtain due to the large extent and hazardous environment of Antarctica.

In this project, the successful applicant will combine various remote sensing data sets, such as backscatter and brightness temperature from Sentinel-1, Sentinel-3, CryoSat-2 and ASCAT, AMSR-E/AMSR2, to study changes in the firn layer. This will be compared to the output of a regional firn model, which you will couple to a snow microwave radiative transfer model to simulate the interaction of electromagnetic waves with the snowpack based on its physical properties. The multi-satellite set of observations and the a-prior knowledge of the microwave scattering sensitivity to snowpack properties from the coupled model will then be used to constrain the firn model in a Bayesian approach.

During your project, you will work in close collaboration with modeling experts at the Institute for Marine and Atmospheric research Utrecht (IMAU). It is expected that you will spend part of your time there. Your results will be used to validate and calibrate their model 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.

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