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

Size-classified ice crystal samples were collected during the Spring of 199 8, at the Jungfraujoch High-Alpine Research Station (3454 m), located in Sw itzerland. A procedure modified from the Guttalgor method, originally devel oped for size-selective sampling of raindrops by Bachmann ct al, (Atmos. En viron. 26A (1992) 1795) was used to sample ice crystals during precipitatio n events. The size-classified ice crystal samples were analyzed using ion c hromatography to determine the concentrations of Na+, NH4', K+, Ca2+, Cl-, NO3-, and SO4- in each size class. For ions associated with coarse mode aer osol, Na+, K+, Ca2+, Mg2+, and Cl-, concentration increased with decreasing ice crystal size, suggesting scavenging by nucleation. For the remaining i ons, mixed behavior was observed suggesting a combination of gas phase scav enging and scavenging via riming. (C) 2001 Elsevier Science Ltd. All rights reserved.