Relationship between Chlorophyll and Environmental Factors of Wuli Lake

In view of the interaction of water environmental factor,the correlation between chlorophyll a and other environmental factors of Wulihu Lake is studied.Taking TP,CODMn,TN and Chl-a for an example,the maximum likelihood method is applied to calculate marginal distribution and parameters of Copula function by choosing the appropriate marginal distribution.Under the given other environmental factors,two-dimensional,three-dimensional and four-dimensional Copula functions are used to represent the conditional return period of Chl-a,respectively.The results show that if only considering a single environmental factor,the concentration of TP and CODMn is higher,the probability of water bloom will be larger and vice versa for TN;if considering two or more environmental factors,no matter what the concentration of environmental factor is higher,the probability of water bloom will be larger.