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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
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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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