This PhD project will use airborne radar data collected over the Greenland Ice Sheet since the early 1990s to reconstruct how the near-surface firn layer has changed over time. As melt intensity on the ice sheet has increased dramatically in recent decades, the firn (compacted snow that covers most of the ice sheet) has been fundamentally altered. Understanding these changes is critical for projecting future sea-level rise and the ice sheet's capacity to store meltwater.

You will analyze airborne radar data collected since the early 1990s, focusing on how the radar signal from the near-surface has evolved over a 25-year period. This will allow you to map long-term changes in firn properties, including the expansion of ice slabs and ice layers affecting the firn’s meltwater storage at regional scale across Greenland. Where feasible, you will also map englacial channels, drainage pathways that connect surface meltwater to the ice sheet bed, and where water input influences ice dynamics and ultimately the rate of mass loss from the ice sheet.

The position is part of the ERC-funded FirnMelt project: Meltwater runoff and retention in Greenland's firn: a process-based approach from observations to projections (www.firnmelt.eu). FirnMelt is a major international research effort combining airborne-, satellite- and ground-based radar, in situ firn observations, and advanced firn- and hydrology modelling. Your work will contribute observations that are essential for evaluating firn- and hydrological models and for understanding ice-sheet-wide change. Your results will be directly integrated with new airborne campaigns planned in 2026 and 2028, as well as ground-based measurements collected along science transects in South Greenland. You will be based at GEUS' Department of Glaciology and Climate in Copenhagen, enrolled as a PhD student at the Technical University of Denmark in Lyngby (Greater Copenhagen), and collaborate closely with project partners across Europe.