变权欧式距离模型在水质综合评价中的应用

Application of Euclidean Distance Model with Varying Weights in Comprehensive Assessment of Surface Water Quality

在加权欧式距离模型的基础上进行改进,针对不同的待评价单元和不同污染性质的污染物,根据污染因子的污染贡献率计算其权重;以n个污染因子为坐标轴,以水质标准中的Ⅰ级水质作为n维空间的"原点",结合权重计算出每个待评价单元以及水质标准中其他各级水质与"原点"的变权欧式距离,并将后者作为划分每个待评价单元水质级别的标准,从而建立了适合水质综合评价的变权欧式距离模型。用该模型对1996-2006年钱塘江支流东阳江许村断面水质监测数据进行了综合评价,并与灰色聚类法和模糊综合指数法的评价结果进行比较,结果与水质实际情况符合较好,验证了变权欧式距离模型应用于水质综合评价的科学性和合理性。

On the basis of Euclidean distance model with weights,this study improved the calculation of the weights.The weights were added to pollution factors according to different pollution contribution rates.The level I of surface water environmental quality standards was taken as the ＇coordinate origin＇.The Euclidean distances with varying weights between units and ＇coordinate origin＇ and between other levels of surface water environmental quality standards and ＇coordinate origin＇ were calculated.The latter served as a distance level evaluation criteria.The Euclidean distance model with varying weights was established,which is suitable for assessment of surface water quality.This model was applied in comprehensive assessment of water quality,using the monitoring water quality data obtained from 1996 to 2006 in Xucun section of the Dongyang River,a tributary of the Qiantang River.The outcome was compared with that of grey clustering model and fuzzy complex index method.The results showed consistence with actual water quality situation,indicating that the Euclidean distance model with varying weights has potential application in comprehensive assessment of surface water quality.