Properties of atmospheric ice crystals at South Pole station

In February 2001, more than 900,000 high-resolution digital images of ice crystals were recorded at the South Pole using two ground-based cloud particle imagers (CPIs), When sorted by number, 30% of the crystals were rosette shapes, 45% were diamond dust and 25% were irregular-shaped crystals. When sorted by area, rosette shapes comprised 50%, diamond dust 30% and irregulars 20%. By mass, the percentages were 57% rosette shapes, 23% diamond dust and 20% irregulars. In 2002, a polar nephelometer (P-N) that measures scattering phase function was incorporated with one of the CPIs. Particle size distributions as a function of maximum dimension and equivalent radius compared favorably with previous studies.