Observations of cloud and precipitation particles on the Avery Plateau, Antarctic Peninsula

Surface-based observations were taken of cloud and precipitation particles on the Avery Plateau (66 degrees 50.34'S 65 degrees 29.58'W), Antarctic Peninsula from 25 November to 13 December 1995. This paper considers cloud parameters on three days during this period when the cloud base reached ground level and snow was falling. It was found that on all three days more ice crystals were present in the cloud than would be expected from simple theoretical considerations. The rate of snowfall decreased as the number of ice crystals increased, the large number of ice crystals present effectively suppressing the formation of large precipitation-sized crystals. The source of the ice nuclei that allowed the formation of the large number of crystals is not known for certain but is thought to be the snow surface, possibly in the form of very fine ice crystals blown from the surface during blowing/drifting snow episodes.