Modelled Antarctic firn depth averaged over 1979-2013 and corresponding brine zones area

The firn densification model IMAU-FDM has been used to simulate the firn density profile around Antarctica. The model is forced at the surface with climate data from the RACMO2.3 regional climate model. Here we provide the depth of three key firn density layers below the surface (750, 800 and 830 kgm^-3), averaged over the period 1979-2013. The data is on a horizontal grid of 27x27 km. The depth of each of these density layers was then subtracted from the surface elevation provided by Bedmap2 to determine where permeable firn exists below sea level. This defines the "brine zone" - the region where seawater may infiltrate the firn layer. We also provide shapefiles mapping the brine zone for each of three stated densities.