干旱区研究

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东天山哈密榆树沟流域夏季降水的化学特征研究

王晓艳,蒋缠文   

  1. (陕西省河流湿地生态环境重点实验室/渭南师范学院化学与环境学院,陕西 渭南 714000)
  • 收稿日期:2017-03-28 修回日期:2017-11-08 出版日期:2018-03-15 发布日期:2018-04-18
  • 作者简介:王晓艳(1984-),女,讲师,博士,主要从事同位素水化学研究. Email: wangxiaoyan_84@163.com
  • 基金资助:
    国家重大科学研究计划项目(超级973项目)(2013CBA01801);陕西省自然科学基础研究计划(2017JQ6080);陕西省高校科协青年人才托举计划项目(20170303);陕西省教育厅重点项目(17JS038);渭南市创新团队专项计划(2015TCTD-2)资助

Chemical Characteristics of Summer Precipitation in Yushugou River basin, Hami, Eastern Tianshan

Wang XiaoYan, Jiang ChanWen   

  1. College of Chemistry and Environment Sciences, Weinan Normal University/Key Laboratory for Ecology and Environment of River Wetlands in Shaanxi Province, Weinan 714000, Shaanxi, China
  • Received:2017-03-28 Revised:2017-11-08 Online:2018-03-15 Published:2018-04-18

摘要: 2013年5—8月按照GB13580.2-92规定的大气降水采样方法,采集了东天山喀尔力克山南坡榆树沟流域32场降水,进行了pH、EC及离子组成的测定,并运用综合描述法、相关性分析、气团来源轨迹、富集因子及端源贡献法探究其来源。结果表明:榆树沟流域夏季降水的pH平均值为6.8,呈弱酸性;电导率在3.79~239 μs·cm-1,受降水量影响明显;阴阳离子质量浓度的平均值分别是SO42->NO3->Cl->F-和Ca2+> NH4+>Na+>K+>Mg2+;SO42-、NO3-、F-和NH4+主要来自于人类活动;Cl-基本来自海盐源,受地壳源的影响甚微;Na+的来源受海盐源和陆源共同影响;Ca2+和K+来自于非海盐源的贡献。

关键词: 大气降水, 化学特征, 离子来源, 气团轨迹, 榆树沟流域, 东天山

Abstract:  As an effective means to study the atmospheric chemical composition change, atmospheric precipitation chemistry could accurately reflect the local atmospheric environmental quality and pollution condition. The precipitation chemistry features far away from human colonies can reflect the background value of atmospheric chemistry, and help to study the atmosphere chemical conversion, transmission and the formation process and mechanism of acid rain. Restricted by precipitation seasonal distribution and the conditions of observation in the river basin, the pH, EC and ion composition of precipitation were analyzed in the Yushugou River basin in EasternTianshan from May to August 2013. The ionic sources were simultaneously investigated. The results showed that the precipitation was neutral with mean pH of 6.8. It suggested that there was no acid rain during the sampling period in study area. The EC ranged from 3.79-239 μs/cm and it was obviously affected by amount of precipitation. With the increase of rainfall, the under cloud wash action diluted the conductive ions in precipitation, at the same time, precipitation conductivity decrease correspondingly. The concentration orders of cations and anions are Ca2+> NH4+>Na+>K+>Mg2+ and SO42->NO3->Cl->F-, respectively. The order of the cationic was exactly the same as that of the elements order in the crust and different from the order of cation concentration in the seawater (Na+ > Mg2+> Ca2+ > K+). It may be due to its geographic location. The Yushugou River basin is located in arid inland areas distributing a large area of desert sand, which makes the ion concentration sequence in the atmospheric precipitation be controlled by terrigenous material. The SO42-/NO3- ratio (1.76) indicated that SO42- was the main acid-causing substance in precipitation. The source of the different ion in summer precipitation is different. SO42-、NO3-、F- and NH4+ mainly comes from man-made sources, such as burning coal, vehicle emissions, and agricultural production activities. Cl- almost came from the sea salt source and crust source has little impact on it. The source of sodium affected by sea salt meanwhile quite part was from terrigenous. Ca2+ and K+ come from the non-sea-salt, which were mainly affected by the earthcrust and human activities. In the study area, there were four precipitation conveying paths which were northwest, southwest, southeast, and north four paths. Northwest path air masses originated from western Russia and Kazakhstan by the way of western Xinjiang. Path moisture originated from Mongolia passed across western Inner Mongolia with low population density, relatively underdeveloped economy, meanwhile industrial agricultural activity was frequent. The human activities exist in northwest pass. Through Northwestern and northern path there was a large area of desert with alkaline soil. It brought a large amount of alkaline substances to the atmosphere where alkaline substances could neutralize the acid precipitation. Southwest path water vapor was from southwest inland areas in China, passing along the eastern Qinghai-Tibet Plateau. The vegetation in southwest inland was in good condition and less affected by human activities. Along the southeast path air mass from the Midwest region in China, the vegetation coverage is very low, so the precipitation was greatly influenced by terrigenous. By studying the chemical characteristics of atmospheric precipitation in the river basin, this paper discussed material source of the precipitation. This research will provide data for further studies of water cycle mechanism in this mountain basin.

Key words: precipitation, chemical characteristic, ion source, Yushugou River basin