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自从2003年三峡水库蓄水以后,其支流大宁河水华频发且频率呈上升趋势。叶绿素a(Chl-a)是指示水体中浮游植物初级生产力的有效指标。采用因子分值-多元线性回归方法研究了大宁河水体11个相关水质因子与Chl-a之间的相关关系。因子分析用于简化水质指标之间的相关性,以因子得分(Score values)为自变量用于多元线性回归分析中。结果发现log(Chl-a)与6个因子分值明显相关,所获得多元线性回归模型为:log(Chl-a)=0.579-0.191×(Score 1)-0.013×(Score 2)-0.013×(Score 3)+0.042×(Score 4)+0.134×(Score 5)-0.059×(Score 6),相关系数R=0.731、相关系数的平方R2=0.535,说明自变量可以解释因变量53.5%的差异性。实测数据验证结果表明:该模型能够较好的预测2010年1～10月水体中Chl-a浓度的峰值和基本变化趋势。
Since the impoundment of the Three Gorges Reservoir in 2003, the frequency of its tributary Daning River has been on an increasing trend. Chlorophyll a (Chl-a) is an indicator of phytoplankton primary productivity in water. A factor score - multiple linear regression method was used to study the correlation between 11 related water quality factors and Chl-a in Daning River water body. Factor analysis was used to simplify the correlation between water quality indicators, using score values as independent variables for multivariate linear regression analysis. The results showed that log (Chl-a) was significantly correlated with the score of six factors, and the multiple linear regression model obtained was: log (Chl-a) = 0.579-0.191 × (Score 1) -0.013 × (Score 2) -0.013 × (Score 3) +0.042 × (score 4) + 0.134 × (score 5) -0.059 × (score 6), the correlation coefficient R = 0.731, and the square of the correlation coefficient R2 = 0.535, indicating that the independent variable can explain 53.5% difference. The experimental results show that this model can predict the peak value and basic trend of Chl-a concentration in water from January to October in 2010.