关键词: 聚类分析, 判别分析, 河流水质, 空间分布, 上海市

Abstract: Water qualities of 16 small and medium rivers (48 sampling sites) and the Huangpu River at 13 sections (42 sampling sites) were investigated in autumn of 2013. A comprehensive analysis was conducted of the findings using the cluster analysis (CA) and discriminant analysis (DA) methods on similarities, differences and controlling factor of spatial distributions of water qualities in the rivers in autumn as affected by type of land use of the surrounding area and type of revetment. Results show that the rivers tended to be high in content of nutrient salts (nitrogen, phosphorus) and organic matter in autumn, but the Huangpu River was on the whole better than the small and medium rivers (P<0.05) in water quality, and its upper reaches were better than the middle and lower reaches; Analysis by location of a river and type of land use of its surroundings shows that the rivers running through the main urban a,reas downtown and areas surrounded by obvious population sources were much worse than those flowing in the suburbs in water quality; With Wujing Section set as a division line, the river south to the section was better than the river north to the section in water quality,Results of spatial cluster analysis indicate that the rivers in Shanghai could be sorted into three groups, that is, the Huangpu River water system and Dazhi River,rivers in the suburban and periurban areas,and rivers in relatively densely populated urban and downtown areas and areas surrounded by typical pollution sources. Dissolved organic carbon (DOC), dissolved oxygen (DO), ammonia nitrogen (NH₄⁺-N), total suspended solids (TSS) and electrical conductivity (EC) were the main water quality indices characterizing spatial heterogeneity of the distribution of water quality.     

Key words: cluster analysis, discriminant analysis, river water quality, spatial distribution, Shanghai