MM4遺傳算法四維變分資料同化系統(tǒng)的基礎(chǔ)研究及其數(shù)值試驗(yàn).pdf

1、南京信息工程大學(xué)碩士學(xué)位論文MM4遺傳算法四維變分資料同化系統(tǒng)的基礎(chǔ)研究及其數(shù)值試驗(yàn)姓名：賴(lài)紹鈞申請(qǐng)學(xué)位級(jí)別：碩士專(zhuān)業(yè)：氣象學(xué)指導(dǎo)教師：馬鏡嫻沈桐立20050501AResearchofMM4GeneticAlgorithm4DVariatonalDataAssimilationSystemandItsNumericalExperimentsAbstractThetechniqueofadjointvariationaldataassi

2、milationhasbeenconsideredasanefectivemethodintheaspectofimprovingthequalityoftheinitialfieldsofnumericalweatherpredication(NWP).Howeveritdoesmakestrongdemandsonmathematicalpropertyofthecostfunction.Inthesametimebyuseofde

3、scendalgorithmtogetthegradientofcostfunctionitiseasytofallintothetrapoflocaloptimization.Geneticalgorithm(GA)asarisingtheorywhichdemandsnoneorlitleonmathematicalpropertyofthecostfunctionhasbeterabilityoffindingtheglobalm

4、inimumthecharacterofuniversalapplicationandeasierexpansion.ThereforeitsnecessarytomakethetechniqueofvariationaldataassimilationhavemorecomprehensiveapplicationinresearchandpracticaloperationbymergingGAintovariationaldata

5、assimilationapplyingitduringthecourseofgainingtheglobaloptimizedinitialfieldsofNWPmodeltoenhancetheaccuracyofNWPmodel.InthispaperGAiscombinedwiththemesoscaleNWPmodelMM4tosolvethepuzzleofadjointvariationaldataassimilation

6、andfourdimension(4D)variationaldataassimilationbasedonGAisestablished.Thetheoreticalbasisanddetailalgorithmarealsointroducedinthispaper.Atthemeantimeaccordingtothepropertyofthevariationalproblemitselfrationalgeneticopera

7、torsandgeneticparametersaredesigned.IntheendnumericalexperimentsofidealfieldrealobserveddataarecarriedoutontheGA4Dvariationaldataassimilationsystem.ResultsshowGA4Dvariationaldataassimilationsystemhasachievedtherelatively