Evaluation of the changes in regional wintertime deposition in Finland during 1976–1993
Evaluation of the changes in regional wintertime deposition in Finland during 1976–1993
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1976-1993年芬兰区域冬季沉积变化评价
DOI：
10.1007/bf01186159
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
K. Peltonen
中科院分区：
文献类型：
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作者：
J. Soveri;K. Peltonen
自1975/1976年冬季以来，芬兰环境署一直在对芬兰的积雪质量进行系统监测。在接近自然状态的地区的53个地下水观测站采集了雪样，当地排放源的影响可以忽略不计。因此，雪中杂质的浓度可被视为背景水平。对积雪样品进行电导率、pH值、主要离子和痕量金属（Cd、Cu、Pb、Ni、Zn和Hg）分析，并通过聚类分析，揭示积雪中主要离子化学组成的区域差异。采用平均连锁聚类法将样点划分为6类。最大的集群-被认为是“平均集群”-位于芬兰中部和北方。溶解杂质总量的最低水平仅出现在由最北方观察点形成的簇中。最高速率的酸化成分，硫酸盐（SO 4），硝酸盐（NO3），铵（NH 4）和氢离子（H+），在芬兰南部。芬兰南部的采样地点分为三个集群。雪的酸度在这些集群之间的变化，除了SO_4和NO_3的沉积是相当大的碱性沉积控制.雪的化学分析的结果被转换成月平均沉积量使用雪的水当量和沉积时间. 1985-1993年期间的SO 4沉积比1976-1984年期间低32%，这大概是由于自20世纪80年代初以来芬兰硫排放量减少了70%。在整个18年期间，NO3-N的沉积水平似乎保持相对稳定，而NH 4-N的沉积量下降了18%。
Snowpack quality has been systematically monitored in Finland since winter 1975/1976 by the Finnish Environment Agency. Snow samples have been taken at the 53 groundwater observation stations in nearly natural state areas, where the impacts of local emission sources have been negligible. Thus the concentrations of impurities in snow can be considered as background levels. Samples were analyzed for conductivity, pH, major ions and trace metals (Cd, Cu, Pb, Ni, Zn and Hg).The regional variation of the chemical composition of major ions in the snowpack was outlined by cluster analysis. Sampling sites were divided into six clusters by average linkage clustering method. The largest cluster — considered as the ‘mean cluster’ — was located in central and northern Finland. The lowest levels of the total amount of dissolved impurities occurred in the cluster formed by the most northern observation site exclusively. Highest rates of the acidifying components, sulphate (SO4), nitrate (NO3), ammonium (NH4) and hydrogen ions (H+), were encountered in southern Finland. Sampling locations of southern Finland were divided into three clusters. The acidity of snow varies among these clusters that in addition of deposition of SO4 and NO3 is considerably controlled by alkaline deposition.The results of chemical analyses of snow were converted to mean monthly depositions using the water equivalent of snow and the time of deposition. Deposition of SO4 during 1985–1993 was 32% lower compared with the period 1976–1984, which presumably results from 70% reduction of sulphur emissions in Finland since the beginning of the 1980s. The deposition level of NO3-N seemed to stay relatively stable during the whole 18 year period while the deposition of NH4-N has decreased 18%.