中文摘要：

通过分析于2009年9月22日—28日期间,在玉龙雪山周边河流白水河采集的河水样品（采样间隔为2 h）,对冰雪融水补给径流的日变化特征及其规律进行了深入研究.结果表明,白水河水中所测的阴离子以SO4^2-含量最高,其次为NO3^-和Cl^-;阳离子中主要以Ca^2＋、Mg^2＋为主,其次为Na^＋、K^＋,不同于冰雪融水中的离子浓度序列Ca^2＋〉Na^＋〉K^＋〉Mg^2＋,反映了流域内基岩岩性对河水化学性质的影响;水体的pH值平均8.6,电导率介于29.9—73.5μS·cm^-1之间,日周期波动幅度较大;受降雨影响时段,各离子含量峰值通常出现在16∶00左右,各离子含量随降雨量的增加呈增加态势（除SO4^2-、NO3^-外）;在无降雨影响下,随径流量的增加,各离子含量表现出减小趋势.

英文摘要：

This study focused on the diurnal variation of major ions in Baishui river around Yulong Mountain. Water samples were collected continuously from 22^th to 28^th September,2009,with a sampling interval of two hours. The samples were analyzed for their chemical composition,and the diurnal variation characteristics and pattern were investigated. The results showed that SO4^2-and NO3^-were the most abundant anions. Meanwhile water samples were mildly alkaline and were rich in Ca^2＋and Mg^2＋cations,which is different from the ion distribution in glacier melt water（ Ca^2＋〉Na^＋ 〉K^＋ 〉Mg^2＋）. It reflected the influence of bedrock lithology on the water chemistry in Mt.Yulong area. Mean pH value of the river water was 8. 6,and the conductively varied between 29. 9 to73. 5,which showed obvious diurnal fluctuation. The peak value of ion concentrations usually appeared at about 16 ∶ 00 each day,displaying positive correlations with the amount of rainfall（ except for SO4^2-,NO3^-） during the period of rainfall. With the increase of runoff,concentrations of most ion showed a decreased trend without rain.