Sampling and chemical analysis of ice crystals as a function of size

Size-classified ice crystal samples were collected during the Spring of 1998, at the Jungfraujoch High-Alpine Research Station (3454 m), located in Switzerland. A procedure modified from the Guttalgor method, originally developed for size-selective sampling of raindrops by Bächmann et al. (Atmos. Environ. 26A (1992) 1795) was used to sample ice crystals during precipitation events. The size-classified ice crystal samples were analyzed using ion chromatography to determine the concentrations of Na+, NH4+, K+, Ca2+, Mg2+, Cl−, NO3−, and SO42− in each size class. For ions associated with coarse mode aerosol, Na+, K+, Ca2+, Mg2+, and Cl−, concentration increased with decreasing ice crystal size, suggesting scavenging by nucleation. For the remaining ions, mixed behavior was observed suggesting a combination of gas phase scavenging and scavenging via riming.