Application Of Annual Precipitation Frequency Analysis Based On Intelligent Optimization Algorithms

Frequency analysis is used widely as the main method of estimating design value of thehydrological variables in engineering hydrology. Hydrological variables, such as annualprecipitation, annual peak flow and minimum flow belong to random variables. The purposeof hydrological frequency analysis is to provide basis for planning and design of waterconservancy project and optimal allocation of water resources by revealing the relationshipbetween hydrological variables and their occurrence probability through mathematicalstatistics method.This thesis summarized research status of hydrological frequency analysis by literatureof domestic and international. Frequency curve type, conventional parameters estimationmethods and parameters optimization which based on intelligent optimization algorithms arestudied. Every parameters estimation method is carried out by programming of MATLABsoftware. The major results are as follows:(1)Distribution functions including normal distribution class, Γ distribution class,extreme value distribution class, Wakeby distribution class and Logistic distribution class andconventional parameters estimation methods were summarized.(2)The setting of algorithm parameters and algorithm flow of three intelligent algorithmswhich include Simulated Annealing Algorithm, Genetic Algorithm and Ant Colony Algorithmwere studied.(3)Twelve distribution functions were selected as frequency distribution of annualprecipitation for ninety sites of Weihe Basin, Three conventional parameters estimationmethods, such as moments method, maximum likelihood method and linear moments methodare used to estimate parameters of every frequency distribution. Using estimation value ofmoments method as initial value, three intelligent algorithms were used to optimizeparameters under three curve optimization rules(OLS,ABS,WLS), these results are expectedto provide the reasonable frequency distribution and parameters estimation method for annualprecipitation frequency analysis for every site.(4)Through frequency analysis of annual precipitation for ninety sites of Weihe Basin,the results showed that, under OLS rule, generalized distribution(GLO) and Simulated Annealing(SA) are suggested as frequency distribution and parameters estimation method forannual precipitation frequency analysis of Weihe Bain, under ABS rule, generalizeddistribution(GLO) and Genetic Algorithm(GA) are suggested as frequency distribution andparameters estimation method for annual precipitation frequency analysis of Weihe Bain,under WLS rule, generalized distribution(GLO) and Genetic Algorithm(GA) are suggested asfrequency distribution and parameters estimation method for annual precipitation frequencyanalysis of Weihe Basin.