Research On Urban Lake Eutrophication Models And MCMC Method Improvement

The research of eutrophication mechanism models has been the hot issue of environment and ecology discipline at home and abroad.However,the effects factors of the eutrophication in urban lakes are complex and difficult to improve the accuration of simulation and prediction.Through analysis of the eutrophication model and improvment of the research methods,the urban lake eutrophication model was established to reflect reality and improve the accuration of model simulation and prediction.This is a serious problem in current study.The eutrophication mechanism model and MCMC methods were the research objects in the study.The simple two trophic eutrophication model was improved to setup the complicated two trophic eutrophication model.Then the fish submodel was added to setup the three trophic eutrophication model;Based on the experiment method and theory,integration of three trophic eutrophication model,the unknown parameters in fish submodel was measured and calculated by using microcosm experiment;AMDR-MCMC and MCMC-GA were established and used to calibration the eutrophication model parameters.In this way,the new methods were used to optimize the sampling range and extraction sampling value;the two dimensional hydraulic information and eutrophication model were combined into the two dimensional urban lake ecosystem dynamic models.A Tianjin urban lake as the research object,three kinds of model of eutrophication and two improved MCMC methods are combined into four group models which were used to calibrate the parameters,simulate and predict the eutrophication model.The performance of the improved MCMC method and eutrophication model were used to compare and discuss.Simulation results shown that MCMC-GA method could effective improve the quality and efficiency of a posterior distribution of model parameters sampling.The three trophic eutrophication model could effective improve model simulation and prediction accuracy.Improved eutrophication model and MCMC method were systematically studied for new urban lake eutrophication modelling method.The main innovation include: realize the three trophic eutrophication model;AMDR-MCMC and MCMC-GA were established and used to calibration the eutrophication model parameters;setup the two dimensional uncertain urban lake eutrophication model.The above models and methods apply to urban lakes water quality simulation.Simulation results have been reflecting the actual situation.