Page 130 - 2024年第55卷第2期
P. 130

imagedatawasusedtocalculatetheinundationfrequencyandvegetationfrequencyofeverypixelonthebarsur
                  face.Therelationshipbetweenthetwofrequencieswereanalyzed,andtheinundationfrequencyconditionsforthe
                  suitablevegetationgrowthareasweredetermined.Theresearchresultsindicatethatbothtypesofmid - channelbars
                  haveconcentratedlowandhighvegetationfrequencyzones ,whilethemediumvegetationfrequencyzonearemore
                  dispersed.Basedonthedistributioncharacteristicsofvegetationfrequency ,thebarsurfaceareacanbedivided
                  intohighcoveragezone,mediumcoveragezone,transitionalzone,andunsuitablevegetationzone,withthecriti
                  calvegetationfrequencythresholdsof80%,50%,and20%,respectively.Theinundationfrequenciesatdifferent
                  locationsonthebarsarethedominantfactoraffectingvegetationfrequency.Onaverageoveralongperiod,thein
                  undationfrequency - vegetationfrequencyrelationshipsonbothtypesofbarsfollowaunifiedlogisticcurve.Accord
                  ingtothiscurve ,criticalinundationconditionsforeachzonearedeterminedasanannualinundationdurationof18
                  days ,43days,and92days,respectively.Atlocationswheretheannualaverageinundationdurationexceed92
                  days,thevegetationfrequencyrapidlydecreasestobelow10%.Themethodsandfindingsinthispapercanprovide
                  referencesforpredictingthevegetationsuccessiontrendindam downstream reachesaftertheimpoundmentofthe
                  ThreeGorgesDam.
                  Keywords:UpperJingjiangRiver;mid - channelbar;vegetation;remotesensingimage;floodingfrequency;
                  criticalconditions

                                                                                    (责任编辑:耿庆斋)



              (上接第 237页)
                               High - precisioncorrectionanduncertaintyanalysismethodfor
                                         remotesensingprecipitationdownscaling

                                                       2,3
                                                                     1,2,3
                                                                                          2,3
                                         1,2,3
                             DONGJiaping    ,YEYuntao ,GUJingjing       ,HUANGJianxiong ,
                                                            2,3
                                                GUANHaozhe ,CAOYin      2,3
                                   (1.SchoolofCivilEngineering,TianjinUniversity,Tianjin 300072,China;
                     2.DepartmentofWaterResources,ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing 100038,China;
                          3.KeyLaboratoryofRiverBasinDigitalTwinningofMinistryofWaterResources,Beijing 100038,China)
                  Abstract:Toeliminatetheinfluenceofhomogeneouspartsinprecipitationfieldsandenhancetheaccuracyofsta
                  tisticalprecipitationdownscalingresults,ahigh - precisioncorrectionmethodisproposedforremotesensingpre
                  cipitationdownscalingbasedontheBayesianHigh - AccuracySurfaceModeling(Bayes - HASM)algorithm.This
                  methodintroducesahigher - precisionsurfacemodelingapproachandcombinesitwithBayesianoptimizationalgo
                  rithmstoachieveautomaticoptimizationofmodelparametersandhigh - precisiondownscalingcorrection.Itad
                  dressestheerrorsandmulti - scaleissuespresentinexistingdownscalingresidualcorrectionmethods.Theresults
                  indicatethatBayesianoptimizationsignificantlyreducestheuncertaintyofhigh - precisionsurfacemodeling ;after
                  Bayes - HASM residualcorrection ,thescatterdistributionofthedownscaledresultsisclosertothe1∶1line.The
                  accuracyindicatorsattheannual ,seasonal,monthly,andten - dayscaleshavebeensignificantlyimproved,
                  withCCandIAindicatorsreachingaround0.9,RMSEhassignificantlydecreased,andRBsignificantlyreduced.
                  Theaboveresultsindicatethatthismethodcansignificantlyreducethemodel ’suncertaintyandeffectivelyeliminate
                  theimpactofhomogeneouspartsoftheprecipitationfield ,therebyimprovingtheaccuracyofthedownscaledprecip
                  itationresults.
                  Keywords:digitaltwinwatershed;highaccuracysurfacemodeling;Bayesianoptimization;statisticaldown
                  scaling;remotesensingprecipitationdata


                                                                                    (责任编辑:韩 昆)







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