天山乌鲁木齐河源冰川积雪化学特征及其季节变化

高海拔雪冰可以记录源自于地球表面的各种化学物质信号.从2002年9月到2005年10月3年的时段内，在天山乌鲁木齐河源1号冰川积累区采集积雪样品，运用比较法、相关分析法等方法，对其中主要离子、不溶粉尘、痕量金属和δ18O等特征及其季节变化进行了分析研究.分析结果表明，积雪离子浓度大小顺序依次为:Ca2+＞SO₄2-＞NO₃-＞Cl-＞NH₄+＞Mg2+＞Na+＞K+，其中Ca2+是主要的阳离子，SO₄2-是主要的阴离子.离子相关性分析表明，除NO₃-之外，其他离子浓度之间均存在较好的正相关.积雪中δ18O值随时间变化表现出与大气温度变化相反的规律.积雪中不溶粉尘和主要化学离子浓度具有明显的季节变化特征，春季期间浓度明显高于其他季节，表明沙尘活动对冰川区化学物质输入有较大贡献；此外，痕量金属(Cd、Pb、Zn、Al、Fe)季节变化特征表明，人类活动的污染物对于研究区雪冰中的化学特征亦有重要影响. 

Chemical Characteristics and Seasonal Variation of Snow on Urumqi Glacier No.1 of the Eastern Tianshan,China

Alpine glacier and snow can record signals of surface earth. From September 2002 to October 2005, Surface snow samples were collected on Urumqi glacier No.1 and chemical characteristics and seasonal variations of major ions, dust, and metal were measured. Results show that the concentration of major ions is Ca2+ > SO₄2- > NO₃- > Cl- > NH₄+ > Mg2+ > Na+ > K+, Ca2+ is the dominant cation, SO₄2- is the dominant anion. All ions have good correlation except NO₃-. δ18O shows minus correlation with air temperature change. Dust and major ionic concentrations in the snow show obvious seasonal change trend, with higher concentrations in spring but lower ones in summer, which indicates the chemical input of dust activities to snow. Temporal changes of heavy metal (Cd, Pb, Zn, Al, Fe) indicate that human activities also have effect on the snow chemistry.