简介:Inthispaper,thesummerclimateof1991istakenasacasetostudytheinfluenceofthetransitionzonemigrationonsummerdroughtinNorthChinabyusingtheregionalclimatemodel(RegCM2).Theresultsshowthatthetransitionzonemigratesinland,thesummermonsoonrainbandof1991alsomovesinland.TheintensiverainbandintheChangjiangRiverValleyduringtheMeiyuperiodmovesnorth.TheprecipitationinNorthChinaincreasesandthesurfaceairtemperaturedecreases.Asaconsequence,itresultsinagoodcirclebetweenecosystemandclimate.Thetransitionzonemigrationchangesfluxtransfersbetweenlandandatmosphere,andexcitessecondarycirculationorcirculationcellsaroundit.Allthosearecloselyrelatedwiththevariationofprecipitation.
简介:Theinfluenceoftheinterannualvariationofcross-equatorialflow(CEF)ontropicalcyclogenesisoverthewesternNorthPacific(WNP)isexaminedinthispaperbyusingthetropicalcyclone(TC)besttrackdatafromtheJointTyphoonWarningCenterandtheJRA-25reanalysisdataset.TheresultsshowedthatthenumberofTCsformingtotheeastof140°EoverthesoutheasternpartofthewesternNorthPacific(WNP)isinhighlypositivecorrelationwiththevariationoftheCEFnear125°Eand150°E,i.e.,thenumberoftropicalcyclogenesesincreaseswhenthecross-equatorialflowsarestrong.CompositeanalysesshowedthatduringtheyearsofstrongCEF,thevariationsofOLR,verticalwindshearbetween200-850hPa,850hParelativevorticityand200hPadivergencearefavorablefortropicalcyclogenesistotheeastof140°EoverthetropicalWNP,andviceversa.Moreover,itisalsodiscussedfromtheviewofbarotropicenergyconversionthatduringtheyearsofstrongCEF,aneastward-extendedmonsoontroughleadstotherapidgrowthofeddykineticenergyovertheeasternpartofWNP,whichisfavorablefortropicalcyclogenesis;butduringtheyearsofweakCEF,themonsoontroughislocatedwestwardinthewesternpartoftheWNP,consistentwiththegrowthareaofeddykineticenergy.Asaresult,therearefewerTCgenesesovertheeasternpartofWNP.Besides,theabruptstrengtheningofaclose-byCEF2-4daysbeforetropicalcyclogenesismaybetheoneofitstriggers.
简介:Basedonnewmultibeambathymetricdataandabout300kmlongsingleseismicprofiles,threetopographicunitswereidentified:thecanyons,fracturalvalleyandsubmarineterraceonthenorthofChiweiIslandwhereisastructuraltransitionzonebetweenthesoutherntroughandthemiddletrough.TheChiweiCanyonandtheNorthChiweiCanyonaretwoofthelargestcanyonsintheEastChinaSea(ECS)slope.Topographicfeaturesandarchitecturesofthemaredescribed.Thestudyshowsthatbothofthemareoriginatedalongfaults.TheevolutionandspatialdistributionoftopographicunitsinthestudyareaarecontrolledmainlybythreegroupsoffaultswhichwereformedandreactiveintherecentextensionalphaseofOkinawaTrough.TheChiweiCanyonwasinitiatedduringthemiddlePleistoceneandguidedbyF4thatisaN-StrendingfaultontheslopeandF1,alargeNW-SEtrendingfaultonthetrough.ThepathwaymigrationfromtheremnantchanneltothepresentoneofChiweiCanyonistheresultofupliftoftiltedfaultblockthatiscoupledtotherecentextensionmovementsofthesoutherntrough.ThesubmarineterraceisdetachedfromtheECSslopebytheNEE-trendingfault.TheNorthChiweiCanyon,developingduringthelatePleistocene,isguidedbyF5,aN-Strendingfault,divertedandblockedbythesubmarineterrace.
简介:从在诺思中国上的2010-14的严重天气报告和合成雷达反射率数据被用来分析严重的对流的风(SCW)的分发事件和他们雷达反射率的组织上的模式。为SCW事件的六个组织上的模式(并且他们的比例)簇房间(35.4%),嚎啕线(18.4%),非线性形状的系统(17.8%),破线(11.6%),单个房间(1.2%),和弓回应(0.5%)。为嚎啕线和破线的山峰月是6月,而它是为另外的四个模式的7月。SCW事件的最高的数字在山上,它通常与簇房间的瓦解的系统被联系。相反,与线性系统联系的SCW主要在平原上发生了,在车站每年记录了不到一个SCW事件的一般水准的地方。有与非线性形状的系统联系的SCW的高频率的区域也经历了与嚎啕线联系的许多SCW事件。对流可得到的势能的价值,能使沉淀的水,0-3-km砍,并且0-6-km砍,比在山上在平原上是可论证地更大的,它在SCW事件的组织上的模式上有明显的效果。因此,地形学可以是在为在诺思中国上的SCW事件的组织上的模式的一个重要因素。
简介:IdentificationofkeySSTzonesisessentialinpredictingtheweather/climatesystemsinEastAsia.WiththeSSTdatabytheU.K.MeteorologicalOfficeand40-yeargeopotentialheightandwindfieldsbyNCAR/NCEP,therelationshipbetweentheEastAsiansummermonsoonandnorthPacificSSTAisstudied,whichrevealstheirinteractionsareofinterdecadalvariation.Beforemid-1970's,thenorthPacificSSTAactsuponthesummermonsooninEastAsiathroughagreatcirclewavetrainandresultsinmorerainfallinthesummerofthenorthernpartofChina.After1976,theSSTAweakensthewavetrainandnolongerinfluencestheprecipitationinNorthChinaduetoloosenedlinkswiththeEastAsiansummermonsoon.ItcanbedrawnthatthekeySSTzoneshavingpotentialeffectsontheweather/climatesystemsinEastAsiadonotstayinoneparticularareaoftheoceanbutrathershiftelsewhereasgovernedbytheinterdecadalvariationsoftheair-seainteractions.Itishopedthatthestudywouldhelpshedlightonthepredictionofdrought/floodspansinChina.
简介:AsimulationofclimatechangetrendsoverNorthChinainthepast50yearsandfuture30yearswasperformedwiththeactualgreenhousegasconcentrationandIPCCSRESB2scenarioconcentrationbyIAP/LASGGOALS4.0(GlobalOcean-Atmosphere-Landsystemcoupledmodel),developedbytheStateKeyLaboratoryofNumericalModellingforAtmosphericSciencesandGeophysicalFluidDynamics(LASG),InstituteofAtmosphericPhysics(IAP),ChineseAcademyofSciences(CAS).Inordertovalidatethemodel,themodernclimateduring1951-2000wasfirstsimulatedbytheGOALSmodelwiththeactualgreenhousegasconcentration,andthesimulationresultswerecomparedwithobserveddata.Thesimulationresultsbasicallyreproducethelowertemperaturefromthe1960stomid-19?0sandthewarmingfromthe1980sfortheglobeandNorthernHemisphere,andbettertheimportantcold(1950-1976)andwarm(1977-2000)periodsinthepast50yearsoverNorthChina.Thecorrelationcoefficientis0.34betweensimulationsandobservations(significantatamorethan0.05confidencelevel).TherangeofwintertemperaturedeparturesforNorthChinaisbetweenthosefortheeasternandwesternChina'sMainland.Meanwhile,thesummerprecipitationtrendturningaroundthe1980sisalsosuccessfullysimulated.Theclimatechangetrendsinthefuture30yearsweresimulatedwiththeCO_2concentrationunderIPCCSRES-B2emissionscenario.Theresultsshowthat,inthefuture30years,wintertemperaturewillkeepawarmingtrendinNorthChinaandincreasebyabout2.5℃relativetoclimatemean(1960-1990).Meanwhile,summerprecipitationwillobviouslyincreaseinNorthChinaanddecreaseinSouthChina,displayingasouth-deficit-north-excessivepatternofprecipitation.
简介:Almosthalfoftheoceanicwatercolumnsexhibitdouble-diffusion.Theimportanceofdouble-diffusioninglobaloceans'saltandheatfluxes,water-massformationandmixing,andcirculationisincreasinglyrecognized.However,suchanimportantphysicalprocessintheoceanhasnotbeenwellstudied.Oneofthereasonsisthedifficultyofparameterizingandquantifyingtheprocesses.Thepaperpresentedhereattemptstoquantifythedouble-diffusivefluxesofsaltandheatintheocean.Previousqualitativeanalysisbyapplyingthewater-massTurnerangle,mTu,totheNorthPacificIntermediateWater(NPIW)layershowedafavorableconditionforsalt-fingeringintheupperNPIWduetotheoverlyingwarm/saltywaterabovethecold/freshNPIWcore,andadoubly-stableconditioninthelowerNPIWwherepotentialtemperaturedecreaseswithdepthwhilesalinityincreases,inducingdoublestratificationwithrespecttobothpotentialtemperatureandsalinity.Thepresentstudygivesaquantitativeestimateofdouble-diffusivefluxesofsaltandheatcontributedbysalt-fingeringintheupperNPIWlayer.
简介:ThelocationandlateQuaternaryactivityoftheCentral-NorthSegmentoftheTaihangMountainsPiedmontfaultzonehavebeenstudiedbyshallowseismicsurveyandcombineddrillexploration.OurresultsshowthattheBaoding-ShijiazhuangfaultandtheXushuifaultwereactiveinthelatePleistocene,butthesouthXushuifaulthasbeeninactivesincethelatePleistocene.Themaximummagnitudeofpotentialearthquakeofthefaultsis6.0.
简介:DISTRIBUTIONOFLOWFREQUENCYWAVESINNORTHPACIFICANDINTRASEASONALABNORMALITYOFTHEWESTERNPACIFICSUBTROPICALHIGHLiXingliang(李兴亮)(Me...
简介:Lomagundi-Jatuli事件(LJE)是保存13C在在世界范围的Paleoproterozoic碳酸盐的+5和+16之间的carb价值。然而,这些旅行的持续时间,振幅和模式仍然保持糟糕抑制了。在北方中国Craton的2.14-1.83GaHutuo组是一>10km厚火山--沉积顺序,包括>5km在在上被扔的厚保存得很好的碳酸盐--对亚tidal环境潮汐。碳酸盐的152件最不改变的样品的公司同位素、元素的分析揭示了三阶段的13C进化。它以只积极的13Ccarb(+1.3到+3.4)在Dashiling和Qingshicun形成在~上演2.1Ga碳酸盐,从积极价值由转变列在后面到震荡在~的积极、否定的价值3000mWenshan,Hebiancun,Jianancun,和Daguandong形成的厚碳酸盐,并且与只否定的13C保存在的carb价值>500mHuaiyincun和Beidaxing形成的厚dolostones。看来许多LJE,特别地那些极其积极的13Ccarb信号,没在Hutuo碳酸盐被记录。只积极的13Ccarb价值(+1.3到+3.4)多半在更低的形成保存了对应于LJE的目的,而随后二个阶段反映LJE和Shunga-Francevillian事件(SFE)的发作的余殃。现在的数据点到碳上的氧的增加的影响从Doucun骑车到Dongye亚群并且证明在北方中国Craton的LJE的结束与在Fennoscandia和南非的那些是将近同时的。
简介:ThecropmodelWorldFoodStudies(WOFOST)wastunedandvalidatedwithmeteorologicalaswellaswinterwheatgrowthandyielddataat24stationsin5provincesofNorthChinafrom1997to2003.Theparameterizationobtainedbythetuningwasthenusedtomodeltheimpactsofclimatechangeonwinterwheatgrowthforallstationsusinglong-termweatherdatafrom1950to2000.Twosimulationsweremade,onewithallmeteorologicaldata(rainfed)andtheotherwithoutwaterstress(potential).Theresultsindicatethatthefloweringandmaturitydatesoccurred3.3and3daysearlierinthe1990sthanthatinthe1960sduetoa0.65℃temperatureincrease.Thesimulatedrainfedyieldsshowthattheaveragedroughtinducedyields(potentialminusrainfedyields)havedecreasedby9.7%overthelast50years.Thisistobecomparedwitha0.02%decreaseinyieldiftheprecipitationlimitislifted.Althoughtheprecipitationduringthegrowingseasonhasdecreasedoverthelast50years,thedroughteffectsontherainfedyieldsremainedtobepracticallyunchangedasthespringprecipitationdidnotdecreasemarkedly.
简介:Thisstudyfocusesonthedecadalvariabilityoftropicalcyclones(TC)overtheWesternNorthPacific(WNP)andhowthesechangesarerelatedtotheMadden-JulianOscillation(MJO).ItwasdonewiththehelpoftheReal-timeMultivariateMJOindexfromtheAustralianGovernmentBureauofMeteorologyoftheCentreforAustralianWeatherandClimateResearch,TCdatafromtheJointTyphoonWarmingCenterbesttrackdatasets,anddailyandmonthlydatasetsfromtheNCEP/NCARreanalysiscenter.TheresultsshowthattheTCfrequencyintheWNPexhibitedastatisticallysignificantdecreaseduring1998-2010comparedtoduring1979-1997.ThedecreaseinTCfrequencyintheWNPmainlyoccurredduringMJOactivephases(i.e.,phases4,5,6,and7).FurtherinvestigationoftheclimatebackgroundandthepropagationdifferencesoftheMJObetween1979-1997and1998-2010wasperformed.TheLaNina-liketropicalseasurfacetemperaturecoolingcausedstrongerWalkercirculationandthusinducedunfavorableatmosphereconditionsforWNPTCgenesisincludingalow-leveleasterlyanomaly,anegativerelativevorticityanomaly,anincreaseinsea-levelpressure,andstrongerverticalwindshear.Moreover,shorteningoftheMJOcycle,declineinthedurationoftheactivephasesintheWNP,andeasterlyanomalyandshrinkageoftheconvectionareaduringMJOactivephasesmayalsopartlyexplainthedecadalvariationofTC.
简介:PrecipitationobservationscollectedatweatherstationsineasternChina,theNCEP/NCARreanalysisdata,thetropicalcyclone(TC)BestTrackDataset,andasensitivitynumericalexperimentwereusedinthepresentstudytoinvestigatetheroleintheEastAsiansummermonsoon(EASM)systemplayedbyfrequentTCactivitiesoverthewesternNorthPacific(WNP).Resultsindicatedthat,inactiveTCyears,theEASMisstrongerandthesoutherlywindsinthelowertroposphereadvancefarthernorthandreachhigherlatitudes.Meanwhile,themonsoonrainbeltremainsinthelowerandmiddlereachesoftheYangtzeRivervalleyforarelativelyshortperiod,leadingtolessprecipitationthere.BoththewesternPacificsubtropicalhighandtheSouthAsianhighweakenwiththenorthwardshiftoftheridgelinesforbothhigh-pressuresystemsaswellastheEastAsiansubtropicalupper-leveljet.Therefore,theimpactsoffrequentTCactivitiesovertheWNPoneachindividualcomponentoftheEASMareinphasewiththoseofthestrongerEASMitself,amplifyingfeaturesofthealreadystrengthenedEASM.