天山乌鲁木齐河源区径流水化学特征及影响因素分析  

Hydrochemical Characteristics and Controls of Runoff at the Headwaters of the Urumqi River, Eastern Tianshan Mountain

作　　者：冯芳[1,2] 李忠勤[1,3] 张明军[1,3] 金爽[1] 王飞腾[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冰冻圈科学国家重点实验室/天山冰川站,兰州730000 [2]中国科学院研究生院,北京100049 [3]西北师范大学地理与环境科学学院,兰州730070

出　　处：《资源科学》2011年第12期2238-2247,共10页Resources Science

基　　金：国家自然科学基金项目(编号:41101066,41171057,41161012);中国科学院知识创新工程重要方向项目(编号:KZCX2-EW-311);冰冻圈科学国家重点实验室自主课题(编号:SKLCS-ZZ-2010-04)

摘　　要：在乌鲁木齐河源区采集两年的大气降水和1号冰川、空冰斗、总控3个水文点逐日定时径流样品,对主要离子、pH、电导率EC和总溶解固体TDS进行了分析。结果表明,大气降水离子类型为Ca2+-Na+-HCO3--SO42-,接近中性;径流离子类型为Ca2+-HCO3--SO42-,呈弱碱性。径流中EC和TDS均值总控>1号冰川>空冰斗,其中1号冰川径流的峰值远高于其它两个水文点。受不同下垫面的影响,1号冰川水文点TDS变化受日径流量影响显著,而空冰斗水文点基本不受影响。径流中离子组成主要受岩石风化作用影响,离子比值和Piper图分析说明控制径流离子的主要过程是碳酸盐、黄铁矿和长石类矿物风化。海盐校正分析得出,大气降水对1号冰川、空冰斗、总控径流离子贡献率分别为4.91%,9.10%和5.42%。通过阳离子通量计算,2006年、2007年1号冰川径流的化学风化侵蚀率分别为18.1t/(km2·a)和12.3t/(km2·a)。Glacierised alpine basins present an ideal environment for studying interactions between water and rock, since chemical weathering rates are generally high and anthropogenic impacts are often minimal. Studies on glacier hydrochemistry are still at an initial stage in China, with less data being published on glacierized catchments. An analytical study of hydrochemical characteristics and controls of the proglacial streams at the headwaters of the Urumqi River were carried out in this study. Over the period from May 2006 through April 2008, a 2-year continuous precipitation and runoff samples were analyzed for major cations （Mg^2＋, Ca^2＋, Na^＋, and K^＋） and anions （SO42-, NO; and Cl-）, pH, electrical conductivity （EC）, and total dissolved solids （TDS）. Results reveal that Ca^2＋ and Na ＋ were the dominant cations, and HCOf and SO,2 were the dominant anions in precipitation. The anions and cations in the streams were dominated by Ca^2＋, HCO;, and SO4^2-. Extensive interactions between meltwater and soil and chemical denudation of mineral solutes contributed much to the stream water, resulting in a higher solute concentration in streams than in precipitation. The average pH value in runoff was alkaline （7.67, 8.08, or 8.47）, whereas in precipitation the average PH value was close to neutral （6.73）. TDS and EC values in runoff samples in a descending order were the Zongkong station, Glacier No. 1 station, and Empty Cirque station. The peak TDS value at Glacier No. 1 station was highest, with large magnitude for TDS values. The TDS yield in runoff was controlled by diurnal discharge at different scales at the three hydrological stations. It was concluded that the major origin of ions in runoff was weathering of rocks. Based on ion ratios and piper trilinear nomograph, main processes controlling the water chemistry were found to be carbonate weathering, pyrite weathering, and feldspar weathering in rocks. Ca^2＋ and HCO3 were the dominant cation and anion during the carbonate weathe

关 键 词：离子浓度 EC和TDS 岩石风化 离子通量 乌鲁木齐河源 

分 类 号：P342[天文地球—水文科学]