以天山乌鲁木齐河流域为例,运用参数比较法、相关分析法,对降水中粉尘颗粒物特征在高山区和郊区随时问变化特征及其差异进行研究。结果表明,降水中颗粒物的浓度、粒径分布及化学要素组成在两个取样点都具有明显的季节变化。颗粒浓度表现为冬-春季节升高而夏一秋季节降低,与降水量成反向变化,反映了降水受中亚沙尘活动的影响明显。颗粒在冬一春季节的粒径分布众数较大,而在夏-秋季节相对较小;且这种变化在高山区和郊区存在差异,可能是局地环境影响造成。颗粒物化学特征的季节差异反映了区域自然环境和人为活动对降水的共同影响。结合HYSPLIT模型对大气降水和粉尘颗粒物的来源进行验证。
Chemical and environmental significance of insoluble particles in precipitation are studied using methods of parameter comparison and correlation analysis at alpine and rural sites on the Urumqi river valley in Tianshan Mountains. The HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model is also employed to exam- ine the transport process of air mass and insoluble particles in this region. Results show that the concentration, the size distribution and the chemical constitutes of dust particles in precipitation all exhibit significant seasonality at both sites. The dust concentration increases in winter and spring seasons and decreases during summer and autumn peri- ods, showing a negative correlation with seasonal changes in precipitation. This indicates the significant influence of Asian dust storm in the river valley. The volume-size distribution reveals that large-sized particles are found in winter and spring seasons, while, small-sized one appears to be in summers and autumns. The seasonal variation in chemical constitutes of dust particles indicates that both regional atmospheric environment and human activities of Central Asia may have influence on the formation of regional precipitation.