基于Mann-Kendall检验和重标极差分析的水质变化趋势

Analysis of Variation Trend of Water Quality Based on Mann-Kendall Test and Rescaled Range Analysis

将Mann-Kendall检验和重标极差(R/S)分析相结合,建立了一套综合分析过去和未来水质变化趋势的方法。首先,用季节性Mann-Kendall检验识别水质时间序列的过去变化趋势;然后,用R/S分析方法计算水质时间序列的Hurst指数(IH),0<IH<0.5、0.5<IH<1.0和IH=0.5分别指示反持续性、持续性和白噪声特征;最后,结合水环境保护规划和进展综合推断水质的未来变化趋势。基于2010—2014年珊溪水库及其6条入库支流TN浓度和CODMn,对该方法进行实例研究。结果表明,未来大部分支流的水质将会停止恶化或得到持续改善,然而水库TN浓度仍无明显下降趋势。水库对TN的滞留效应较强,且污染来源较多,水质的根本性改善将是一个长期的过程。除了继续控制入库支流污染,还要控制消落带污染和内源污染。

A comprehensive set of methods was established based on MannKendall test and rescaled range （R/ S） analysis for analysis of variation trends of water quality in the past and future. Firstly, seasonal MannKendall tests were performed to determine variation trend of water quality time series in the past. And then, R/ S analysis was done used to calculate Hurst indexes （IH ） of the water quality time series（0 〈 IH 〈 0.5, 0.5 〈 IH 〈 1.0 and IH = 0.5 indicates antipersistence, persistence and white noise characteristics, respectively）. And in the end, variation trend of water quality infuture was extrapolated by taking into comprehensive account the water environment protection program and its progress.Furthermore, this approach was demonstrated using the data of TN concentrations and CODMn in the Shanxi Reservoir andits six tributaries during the period of 2010-2014 as an example. Results show that water quality in most of its tributarieswill stop deteriorating or go on improving in future, but TN in the reservoir will not display any declining trend, becausethe reservoir has a high TN retention capacity and numerous pollution sources. The reservoir has a long way to go before itswater quality is fundamentally improved. In addition to keeping on controlling incoming pollution from its tributaries, countermeasures should be taken to control pollution of the waterlevelfluctuatingzone and its endogenous pollution.