Microparticle Variations in Snowpits from Mt.Geladaindong in the Source Region of Yangtze River and Its Environmental Significance
长江源区各拉丹冬峰雪冰中微粒季节变化及其环境意义

To study the variations of microparticles and their origins, microparticles concentrations, stable oxygen isotope (delta18 O) and major ion concentrations were analyzed in snow samples collected from Mt. Geladaindong in the source region of Yangtze River. The correlation coefficents of different size microparticles in three snowpits are above 0.9 (significant at the 99% level), respectively. Microparticle concentrations have distinct seasonal variations, about 2-4 times higher in non-monsoon season than those in monsoon season, and are consistent with variations of delta18 O, Ca2+, Mg2+ and SO4(2-). Microparticle fluxes in non-monsoon season in three snowpits are 73.6%, 92.3% & 97% of total annual fluxes, respectively. Air mass backward trajectories over Mt. Geladaindong region were analyzed using the HYSPLIT_4 model, and microparticles in Mt. Geladaindong snow were mostly influenced by dust aerosols from the northwestern Tibetan Plateau, South Asia. Coarse particles may come from the local rocks near glaciers. Research of seasonality of microparticle in snow could provide the information on modern environment processes, and is the base of further interpretation of ice core records.