西藏巴松措冷季水化学特征及其影响因素

于2018年12月（冷季），结合水体现场理化参数和入湖河流，湖泊表层，湖泊垂直分层及出水口各样点水样分析结果对其水化学组成和分布特征以及影响因素进行了研究.结果表明，冷季巴松措水体呈弱碱性.湖区TDS含量较低，平均值仅达107mg/L.湖区平均水温为5.7℃，在水深45~60m范围内存在温度跃变，但变化梯度较小.空间上，各现场理化参数值从入湖河流到湖泊表层且沿垂直方向至最深处均有一定的变化规律，但是这些变化并无显著性差异（P>0.05）.巴松措湖泊水体溶解相中，Ca²⁺和HCO₃^-为主导离子，分别占阳离子和阴离子总量的80.35%和72.95%.各主要离子浓度在平面空间分布上表现为入湖河流高于湖泊表层，汇入湖泊后趋于平稳的趋势.在垂直空间分布上却呈随水深增加而轻微增大的趋势.巴松措水化学类型为HCO₃·SO₄-Ca型.流域内受岩石风化作用的影响，特别是碳酸盐岩的风化过程是影响巴松措水化学组成和分布特征的主要控制因素.

Hydrochemical characteristics and its controlling factors of Basong Lake in cold season in Tibet

In Dec. 2018, study on hydrochemical characteristics and its controlling factors of Basong Lake was carried out. Water samples were collected from the lake surface, vertical layers, inlets and outlets river and, on-site measurement were performed for various physicochemical parameters. The results showed that the Basong Lake overall was slightly alkaline. The measured TDS were relatively low, with an average value of 107mg/L. The average water temperature in the lake area was 5.7℃, with a thermocline appeared at the depth of 45~60m. However, since the temperature variation was minor, there was no significant difference between these measured physicochemical parameters at each sampling sites (P>0.05). Among major ions, Ca²⁺and HCO₃^- were the two dominants,account for 80.35% and 72.95% of the total cations and anions, respectively. Spatially, contents of the major ions in the inlet rivers were generally higher than that of lake surface, then after showed a homogeneous feature over the lake surface. In contrast, vertically, the contents of the major ions were slightly increased with an increasing water depth. The water chemistry type of the Basong lake was HCO₃·SO₄-Ca type. Weathering of rocks in the lake catchments, especially carbonate weathering was the major controlling factor that determined the composition and distribution of ionic contents in the lake area.