| 祁连山中段降水化学的环境意义研究 |
| 摘要点击 2456 全文点击 1446 投稿时间：2014-05-20 修订日期：2014-07-21 |
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| 中文关键词 降水 化学 大气环流 来源 祁连山 |
| 英文关键词 precipitation chemical atmospheric circulation source Qilian Mountain |
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| 中文摘要 |
| 运用相关分析、趋势分析、富集因子法、海盐示踪法和HYSPLIT模型，对2012-07-23~2013-11-12祁连山中段葫芦沟流域 降水常量离子的化学特征分析表明，降水中离子浓度大小顺序为Ca2+ >SO42- >Mg2+ >Cl- >Na+ >NO3- >K+，其中SO42-和Ca2+是高浓度离子，阳离子总浓度显著高于阴离子总浓度；降水电导率的变化范围为 2.26~482μS·cm-1，平均值为 41.9 μS·cm-1；区域降水为 SO42--Mg2+-Ca2+型，上述 3种离子的浓度占离子总浓度的 70%以上；就季节变化而言，降水离子在夏季呈最低浓度，而在冬、春季降水量小但离子浓度高，表现出典型的"碱雨"特征；中亚和我国西北干旱区随西风环流带来的区域陆源物质是化学离子的主要来源，人为污染源产生的气溶胶是次要来源；更重要的是，不同大气环流背景下降水离子浓度也呈现不同特征，主要表现为季风源降水、混合源降水（季风和西风的影响）和西风源降水，主要是由于不同大气环流条件下的降水淋溶过程及其强度所致. 此外，降水离子浓度与降水量、风速之间的相关性反映了局地气候环境的影响. |
| 英文摘要 |
| A total of 90 precipitation samples were collected from individual precipitation events at the Qilian Alpine Ecology & Hydrology Research Station (Hulugou Station, 30°47'N, 90°58'E; 3260 m a.s.l) located in the central Qilian Mountains from August 2012 to November 2013. All samples were analyzed for major cations (Na+, K+, Ca2+ and Mg2+), anions (Cl-, NO3- and SO42-) and conductivity. Precipitation EC values ranged from 2.26 to 482 μS·cm-1 with an average value of 41.9 μS·cm-1. The precipitation was of SO42--Mg2+-Ca2+ type, which contributed>70% to the total ionic concentration. The same as the precipitation alkalinity, precipitation events occurred around summer showed lower concentrations, while it had higher concentrations in winter and spring with little precipitation and larger wind speed. Enrichment factor (EF), correlation and factor analysis indicated that regional crustal aerosols and species from central Asian and northwestern China arid regions brought by the westerly circulation were the major sources for these ions, some dust from human pollution were the secondary sources, and the contribution of sea salt was the least due to the long distance transport. These characteristics could be also confirmed by the correlation between ionic concentrations and metrological data in the study region. It is also interesting that the precipitation chemistry was different under the different atmospheric circulation: the monsoon precipitation, the interaction precipitation events (influenced both by monsoon and westerly) and the westerly precipitation. |
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