College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions of MOE, China Agricultural University, Beijing, 100193, China; Xizang Agriculture and Animal Husbandry College, Nyingchi, Tibet, 860000, China; Key Laboratory of Forest Ecology in Tibet, Ministry of Education, Xizang Agriculture and Animal Husbandry College, Nyingchi, Tibet, 860000, China.
College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions of MOE, China Agricultural University, Beijing, 100193, China.
Environ Pollut. 2019 Oct;253:560-568. doi: 10.1016/j.envpol.2019.07.055. Epub 2019 Jul 12.
Chemical compositions of fog and rain water were measured between July 2017 and September 2018 at Sejila Mountain, southeast Tibet, where fog events frequently occurred in original fir forests at altitude 3950 m. Fog water samples were collected using a Caltech Active Strand Cloud Collector (CASCC), and rain samples were collected using a precipitation gauge. Differences were observed between fog water and rain composition for most analyzed ions. Ion abundance in fog water was Ca > Cl > Na > SO > Mg > NH >K > NO whereas an order of Ca > Na > Cl > Mg > SO > NO > K > NH was observed for rain water. All ion concentrations were higher in fog water than in rain water. Additionally, Ca was the dominant cation in both fog and rain samples, accounting for more than half of all measured cations. NH and SO concentrations were notable for being higher in fog than rain water when compared with other ions. For trace elements, Al, As, Mn and Se were the most abundant elements in fog water; only Al and As were detected in rain water. Seventy-two hour back-trajectory analysis showed that air masses during fog and/or rain events mainly came from the south of Sejila Mountain. Spearman correlation analysis and source contribution calculations indicated that both marine and terrestrial sources contributed to the observed ion concentrations. Considering the higher concentrations of NH and higher ratio of NH/NO measured in fog than in rain, we suggest that quantification of fog nitrogen deposition and its ecological effect in this area should be given more attention.
在西藏东南部的色季拉山，我们于 2017 年 7 月至 2018 年 9 月间测量了雾水和雨水的化学成分，那里的原始冷杉林经常出现雾凇现象，海拔约 3950 米。我们使用加利福尼亚理工学院主动 Strand 云收集器（Caltech Active Strand Cloud Collector，简称“CASCC”）收集雾水样本，使用雨量计收集雨水样本。大多数分析离子的雾水和雨水成分存在差异。雾水中离子丰度为 Ca > Cl > Na > SO > Mg > NH >K > NO，而雨水中的离子丰度顺序为 Ca > Na > Cl > Mg > SO > NO > K > NH。雾水中所有离子浓度均高于雨水中的浓度。此外，Ca 是雾水和雨水样本中主要的阳离子，占所有测量阳离子的一半以上。与其他离子相比，NH 和 SO 的浓度在雾水中更高。对于微量元素，Al、As、Mn 和 Se 是雾水中最丰富的元素；仅在雨水中检测到 Al 和 As。72 小时后向轨迹分析表明，雾和/或雨事件期间的气团主要来自色季拉山南侧。Spearman 相关分析和源贡献计算表明，海洋和陆地源都对观察到的离子浓度有贡献。考虑到雾水中 NH 的浓度较高，且 NH/NO 的比值高于雨水中的比值，我们建议应更加关注该地区雾态氮沉降及其生态效应的定量评估。
