滇池外海水体叶绿素a与水质因子关系研究

使用近5年滇池外海的水体理化指标监测数据，分析了滇池外海水体叶绿素a的时空分布特征，并使用多元逐步回归分析叶绿素a与水质因子的关系。研究结果表明，滇池外海水体叶绿素a浓度为0．003～0．475mg／L，长年平均浓度为0．063mg／L，每年2月最低，8月最高，夏季最高，冬季最低。近5年各测点年平均值2004年平均浓度最高，2005年最低。滇池外海叶绿素a的空间分布呈现出北高南低，中部呈现西高东低的态势。各水质因子在不同的位置对叶绿素a浓度的影响显著程度不一样，但叶绿素a浓度总体与透明度呈现负相关，与pH值呈显著的正相关，与水温呈现正相关。通过多元逐步回归分析，滇池外海水体叶绿素浓度回归方程在不同位置有1～4个因子入选，外海叶绿素a平均浓度的回归方程为：Chla=-0．336＋0．002·WT＋0．028·TN＋0．034·pH。

A STUDY OF THE RELATIONSHIP BETWEEN THE WATER BODY CHLOROPHYLL a AND WATER QUDLITY FACTORS OF THE OFFCOAST OF DIANCHI LAKE

Based on the monitoring data of the water quality factors in recent 5 years, the thesis makes an analysis of the space-time distribution characteristic of the water body Chlorophyll a of the off coast of Dianchi Lake. And it also attaches an analysis of the relationship between Chlorophyll a and the water quality factors by multiple stepwise regression method. The results indicate that the concentration of the water body Chlorophyll a of the off coast of Dianchi Lake is 0. 003 -0. 475 rag/L, and the long-term average concentration is 0. 063mg/ L. The concentration is the highest in August and lowest in February which means the highest in summer, and lowest in winter. During the recent 5 years, the highest annual average concentration was in 2006, the lowest was in 2005. The spatial distribution of Chlorophyll a in Dianchi Lake has shown a trend that it＇s higher in the north and lower in the south, while in the central lake area, it＇s higher in the west and lower in the east. It also shows that the influential water quality factors on the concentration of the water body Chlorophyll a are different in different locations. Moreover, the concentration of the Chlorophyll a overall has a negative correlation with the SD but a positive correlation with the pH value and the WT. In the multiple regression analysis, we select l ~ 4 factors of the regression equation of the water body Chlorophyll a concentration due to different locations. And the regression equation of average concentration of the off coast Chlorophyll a is： Chla = - 0. 336 ＋ 0. 002 · WT ＋ 0. 028 · TN ＋ 0. 034 · pH.