A snow density dataset for improving surface boundary conditions in Greenland ice sheet firn modeling

The surface snowdensity of glaciers and ice sheetsis of fundamental importance in converting volume to mass in both altimetry and surface mass balance studies, yet it is often poorly constrained. Site-specific surface snowdensities are typically derived from empirical relations based on temperature and wind speed. These parameterizations commonly calculate the average density of the top meter of snow, thereby systematically overestimating snowdensity at the actual surface. Therefore, constraining surface snowdensity to the top 0.1 m can improve boundary conditions in high-resolution firn-evolution modeling. We have compiled an extensive dataset of 200 point measurements of surface snowdensity from firncores and snowpits on the Greenland ice sheet. We find that surface snowdensity within 0.1 m of the surface has an average value of 315 kg m−3 with a standard deviation of 44 kg m−3, and has an insignificant annual air temperature dependency. We demonstrate that two widely-used surface snowdensity parameterizations dependent on temperature systematically overestimate surface snowdensity over the Greenland ice sheetby 17–19%, and that using a constant density of 315 kg m−3 may give superior results when applied in surface mass budget modeling.