Abstract: It is a part of the PGPI (Program for Processe Investigation) to study the relationship between insoluble microparticles and magnesium, and it was initiated at the Tianshan Glaciological Station in July 2002. In this paper, the vertical distribution and evolution process of insoluble microparticle and magnesium concentration along vertical profiles of snow pits as well as their seasonal variation were studied by weekly sampling from a snow pit (4 130 m a. s. l., in the percolation zone) on Glacier No.1 in the east Tianshan Mountains from September 2003 to September 2004. The analyzed results of insoluble microparticles and magnesium concentration reveal that their change trends were similar in both surface snow and along vertical snow profiles. [JP2]In winter, insoluble microparticles and magnesium concentrations in surface snow layer were altered slightly by sublimation and wind erosion. In early summer, as snow melting occurred in the upper part of snowfirn pack, snow meltwater carried microparticles and magnesium to different depths of the underlying snowfirn layers, all the surface elements might be leached out from the upper layers at the end of the ablation season. Correlation coefficient between concentration of insoluble microparticles and magnesium along vertical profiles of snow layer showed a significant negative correlation with temperature.

Key words: insoluble microparticle, aerosol, mineral dust, Mg^2+ , concentration, deposition process, Glacier No.1, Urumqi River, Tianshan Mountains