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 Pen insula from 25 November to 13 December 1995. This paper considers cloud par ameters 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 c rystals were present in the cloud than would be expected from simple theore tical considerations. The rate of snowfall decreased as the number of ice c rystals increased, the large number of ice crystals present effectively sup pressing 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/d rifting snow episodes.