Assessing annual trends, monthly fluctuations and between-station relationship of sulphate deposition in the Turkey Lakes Watershed

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• 作者：Rong Zhu ; Abdel H. El-Shaarawi ; Xingde Duan ; Zilin Wang and Renjun Ma
• 刊名：Environmetrics
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：27
• 期：5
• 页码：256-266
• 全文大小：827K
• ISSN：1099-095X

文摘

Water deposition of pollutants can be a good indicator of both air and water quality in a region of interest. In this paper, we study sulphate deposition change over time in a network of multiple monitoring stations in the Turkey Lakes Watershed in Sault Ste. Marie, Ontario, Canada. As there is generally substantial correlation among sulphate deposition observed over time and space, we incorporate temporally correlated multivariate random effects into Gamma regression models to account for the temporal dependence within each station and between-station dependence in space. We applied our new approach to analyse monthly average sulphate depositions between 1983 and 2003. We found the observed increase of sulphate deposition between 1994 and 2003 was not significant, that is, annual trends in sulphate deposition had stabilized since 1994. Our analysis also quantified increasing sulphate deposition from upstream to downstream and its monthly fluctuations from higher in winter to lower in summer. Understanding of these sulphate deposition trends is of great policy relevance to environmental conservation. Copyright