SOLUBLE SPECIES IN AEROSOL AND SNOW AND THEIR RELATIONSHIP AT GLACIER1, TIEN-SHAN, CHINA

Simultaneous sampling of aerosol (n = 20) and snow (n = 114) was made at Glacier 1, Tien Shan, between May 19 and June 29, 1996. Similar tem poral patterns of some major ion (calcium, magnesium, potassium, Sodiu m, chloride, and sulfate) concentrations between snow and aerosol show that snow chemistry basically reflects changes in the chemistry of th e atmosphere. This gives us confidence in the reconstruction of past a tmospheric change using some snow data. There are no significant corre lations between aerosol and snow samples for ammonium and nitrate. Thi s suggests that postdepositional and/or postcollection processes may a lter ammonium and nitrate concentrations in snow. The fact that the me asured cations in aerosol and snow always exceed the measured anions s uggests that the atmosphere is alkaline over Glacier 1? Tien Shan. In aerosol and snow samples, calcium is the dominant cationic species, wi th sulfate and presumed carbonate being the dominant anions. There ii a very good inverse relationship (r = 0.96) between the equivalence ra tio of calcium to sulfate and the ratio of ammonium to sulfate in aero sols, but this relationship does not hold for snow. This further sugge sts that postdepositional and/or postcollection processes exert import ant controls on ammonium concentrations in snow. Although melt-freeze cycles might increase the concentration of all crustal species through progressive dissolution of dust, these cycles seem most important for magnesium and carbonate.