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tionthicknesscausestheaircoretochangefromastablepenetrationwhenthereisnosedimentaccumulationtofre
                  quentoscillationanddeviationfromtheflushingorifice.Underdifferentwaterandsedimentconditions,theaircore
                  diameterdecreasesby5.95% to53.07%,whichincreasesthesedimentdischargewaterconsumptionrate.The
                  rangeandintensityofthefreevortexintheVSBdecreaseasthethicknessofthesedimentaccumulationbodyin
                  creases ,andtheaveragetangentialvelocityunderthedesignflowdecreasesby20% to55%.Thewidthofthean
                  nularlow - velocityzonebetweentheforcedvortexandthefreevortexincreasesby33% to40% comparedtothesit
                  uationwithoutsedimentaccumulation,whichisnotconducivetothespiralflowseparationofwaterandsediment.
                  Theintensityofthetransversecirculationweakens,whichisnotconducivetothetransferofsedimenttotheflush
                  ingorifice ,leadingtointensifiedsedimentaccumulation,therebyfurtherreducingtheswirlintensity.Theradial
                  andverticalturbulentintensitiesincreaseby10% to110% and12% to120% respectivelywiththeincreaseinsedi
                  mentaccumulationthickness ,makingitdifficultforsuspendedsedimenttosettle,andtheinterceptionrateissig
                  nificantlyreduced.
                  Keywords:vortex - settlingbasins;modelexperiments;sedimentationbody;aircoreshape;flowfieldcharac
                  teristics


                                                                            (责任编辑:鲁 婧 韩 昆)


              (上接第 226页)
                            Analysesoftheevolutionandinfluencingfactorsofnaturalrunoffin
                                            ChinabasedonSTLdecomposition

                                                                                       6
                                                          1,2,3
                                                                         4,5
                  ZHAOYilin  1,2,3 ,LIUWenfeng 1,2,3 ,LIZheng  ,XUZongxue ,YANGKun,WUDefeng         1,2,3
                 (1.StateKeyLaboratoryofEfficientUtilizationofAgriculturalWaterResources,ChinaAgriculturalUniversity,Beijing 100083,China;
                   2.NationalFieldScientificObservationandResearchStationonEfficientWaterUseofOasisAgricultureinWuweiofGansuProvince,
                    Wuwei 733000,China;3.CenterforAgriculturalWaterResearchinChina,CollegeofWaterResourcesandCivilEngineering,
                        ChinaAgriculturalUniversity,Beijing 100083,China;4.CollegeofWaterSciences,BeijingNormalUniversity,
                         Beijing 100875,China;5.BeijingKeyLaboratoryofUrbanHydrologicalCycleandSpongeCityTechnology,
                        Beijing 100875,China;6.DepartmentofEarthSystemScience,TsinghuaUniversity,Beijing 100084,China)


                  Abstract:Asakeyindicatorofwaterresources,riverrunoffexhibitsconsiderablespatio - temporalvariabilityin
                  itslong - termchanges.Previousresearchhasprimarilyfocusedonmeasuredrunoffwithoutexcludingtheimpacts
                  ofshort - termfactors.Thisarticleappliedamethodthatcombinestimeseriesdecompositionwithtraditionaltrend
                  analysis ,basedonnaturalhydrologicalprocessesundisturbedbyhumanactivities,todiscernthedynamicsof
                  naturalriverrunoffandexploreitsinfluencingmechanisms.Utilizingagriddednaturalrunoffandregionalmeteoro
                  logicaldrivingdatasets ,thisstudyexaminedthespatialdistributionandtrendsofnaturalrunoffacross218tertiary
                  basinsinChinafrom1979to2018.TheanalysisemployedtheSeasonal - Trenddecompositionprocedurebasedon
                  Loess (STL)fordecomposingnaturalrunoffseries.Additionally,multiplelinearregressionwasemployedtoi
                  dentifytheprimarymeteorologicalfactorsaffectingnaturalrunoff.Thefindingsrevealedthat,priortoSTLdecom
                  position,only35.8% ofthe218tertiarybasinsexhibitedasignificanttrendinnaturalrunoff.Post - STLdecompo
                  sition,however,thechangingtrendbecamemoreobvious,with75.7% ofthebasinsshowingasignificanttend
                  ency.FollowingtheSTLdecomposition,84.4% ofthetertiarybasinsdemonstratedanincreasingtrendinnatural
                  runoff ,withhighstatisticalsignificance.Precipitationemergedasthemostimportantfactorinfluencingnatural
                  runoffvariationsinmostbasins ,followedbylong - waveradiationandspecifichumidity.Theinfluencingfactors
                  variedincomplexitybetweennorthernandsouthernChina,withthenorthernbasinsexhibitingmoreintricatein
                  fluencingfactors.Thisstudyprovidesreferenceforcomprehensivelyunderstandingthecharacteristicsofrunoff
                  patternsinChinaunderchangingenvironments.
                  Keywords:naturalrunoff;tertiarybasin;STLdecomposition;runofftrend;influencingfactors


                                                                                    (责任编辑:李 娜)



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