Drifting snow measurements on the Greenland Ice Sheet and their application for model evaluation

This paper presents autonomous drifting snow observations performed on the Greenland Ice Sheet in the fall of 2012. High-frequency Snow Particle Counter (SPC) observations at 1m above the surface provided drifting snow number fluxes and size 5 distributions; these were combined with meteorological observations at six levels. We identify two types of drifting snow events: katabatic events are relatively cold and dry, with prevalent winds from the southeast, whereas synoptic events are short-lived, warm and wet. Precipitating snow during synoptic events disturbs the drifting snow measurements. Output of the regional atmospheric climate model RACMO2, which includes the 10 drifting snow routine PIEKTUK-B, agrees well with the observed near-surface climate at the site, as well as with the frequency and timing of drifting snow events. Direct comparisons with the SPC observations at 1m reveal that the model overestimates the typical size of drifting snow particles, as well as the horizontal snow transport at this level.