Understanding the evolution of firn is important for several reasons. Firstly, knowing the depth and the age of firn at pore close-off, and how these change through time, is essential for accurate interpretations of climate records from ice cores. Second, converting spaceborne measurements of volume change into mass change requires estimates of firn thickness and density changes through time. Finally, recent work has demonstrated the importance of meltwater retention in firn in buffering the Greenland and Antarctic ice sheets’ contribution to sea level. Although the spatial and temporal scales of these problems vary, they are united by a common need to understand the underlying physics of firn and its evolution.

We invite contributions on the subject of firn and firn evolution on all temporal and spatial scales. These may include: advances in measurements or observations of firn and firn processes at the microscale (e.g. microstructural studies) or macroscale (e.g. compaction measurements) and all types of firn modelling. We are particularly interested in assessments of uncertainty based on firn modelling and observations and work demonstrating important directions for future firn research.