简介:Thelongcontroversyovertheterm‘Quaternary'asachronostratigraphicunitmaybereachinganapotheosis,judgingfromrecentpapers(PillansandNaish,2004;Gibbardetal.,2005;andreferencestherein).Thedebateisnolongercenteredonwhetherthereshouldbeaplaceinthegeologicaltimescaleforaunittermed‘Quaternary'-despiteitsdubiouspast,itcannotbedeniedthatalargebodyofearth-historicalresearchisstronglyidentifiedwiththisterm.ThechallengenowconcernsanappropriaterankanddefinitionofQuaternarywithregardtootherchronostratigraphicunits.Severaloptionshavebeenproposed(PillansandNaish,2004),andGibbardetal.(2005)encourageadebateonthesebeforedecisionisreached.Inthisbriefnote,wedescribeanarrangementnotpreviouslyconsideredthatseemsadvantageous.Itisinstructive,however,tofirstreviewthePleistoceneSeriesandNeogeneSystem,thetwounitsthataredirectlyaffectedbyintroductionoftheQuaternaryintothechronostratigraphichierarchy.
简介:<正>ThenorthChinablockisborderedonthenorthbytheYinShan,onthewestbytheHelanShan,onthesouthbytheQinLing-DabieShan,andtotheeastbythesea.ThesouthChinablockisborderedonthenorthbytheDabaShan(QinLing)-DabieShah,onthewestbytheLongmenShan-DaliangShan,onthesouthwestbythegreatfaultalongtheRedRiver,andtotheeastandsoutheastbythesea.Thetopographyofthenorthissimpleandeven,likeatwo-stagedterracehigherinthewest.Thoughthatofthesouthisalsohigherinthewest,itisveryunevenwithaboundantlowerandmiddlemountainsandhills.TheQinLing-DabieShanisanarrowbeltwiththe
简介:UsingNCEPreanalysisdataandanairflowtrajectorymodelbasedontheLagrangianmethod,theHybridSingle-ParticleLagrangianIntegratedTrajectory(HYSPLIT)model,thedailybackwardtrajectoriesontheheightof850hPaabovetheSouthChinaSea(SCS)areaaresimulatedfromApriltoJune.TheonsetdateoftheSCSsummermonsoonfrom1948to2009isdeterminedaccordingtothesimulatedsourceofairflowinthemonitoredareaoftheSCS.ByanalyzingtheSCSmonsoononsetdatesoverthe62years,wefoundthatthenumberofyearsinwhichtheSCSmonsoononsetisearlieraccountsfor13%,andthelateryears14%,thenormalyears73%,ofallthe62years.AnalyseswiththeLagrangianmethod,doneincomparisonwiththeothertwomethodswhichcombinewindandpotentialpseudo-equivalenttemperature,wereperformedtodeterminetheonsetdatesoftheSCSsummermonsoon.Insomeyears,thesourceofthesouthwestairflowinthemonitoredareaoftheSCSisinthesubtropicalregionbeforetheonsetoftheSCSmonsoon,sotheairflowfromthesubtropicscanbedistinguishedwiththeairflowfromthetropicsbyusingtheLagrangianmethod.Thesimulationbythetrajectorymodelindicatedthatinsomeyears,aftertheonsetofSCSsummermonsoon,theSCSwillbecontrolledbythesoutheastwindinsteadofthesouthwesterlyusuallyexpected.
简介:Applyingtheempiricalorthogonalfunction(EOF)analysistotheseasurfacetemperature(SST)fieldofthetropicalPacificandIndianOceansfordeterminationofthefirsteigenvectorfield,thecurrentworkrevealsthattherearesignificantzonalgradientsofSSTinallseasonsoftheyearinthenorthwesternandeasternIndianOceanandequatorialcentralandeasternPacificandwesternPacific.ItisalsofoundthatthevariancecontributionratesofthefirstEOFmodeofeveryseasonismorethan33%.ThisshowsthatthiskindofspatialdistributionoftheSSTisstable.ThispatternisnamedPacific-IndianOceansSSTAmode.Throughcarefulanalysisandcomparison,anindexofthemodewasdefined.
简介:Inthisarticle,anewdefinitionfortheNorthHuaiheRiverrainyseason(NHRS)ispresentedusingsummerdailyprecipitationinEastChinaandsubtropicalhighridgeaxisat500hPa.BycalculatingtheannualprecipitationamountsintheNHRSandMeiyuoftheYangtze-HuaiheRiversbasin(YHMY)from1961to2009,thedatesofprecipitationbeginningandendingaswellasthedurationofthetworainyseasonsinthe49yearsareanalyzed.AtmosphericcirculationcharacteristicsinpositiveandnegativeprecipitationanomalyyearsduringtheNHRSarealsostudied.Resultsareshownasfollows.(1)ThenewdefinitionfortheNHRSismucheasiertouse.Itinvolvesonlytwometeorologicalfactors,makingitsapplicationmorepractical.ItcanalsodistinguishtworainyperiodsoftheNHRSmoreobjectively.(2)TheaveragedurationoftheNHRSissimilartothatoftheYHMY,exceptthatitsaveragedatesofbeginningandendingareaboutoneweeklaterthanthoseoftheYHMY.TheaverageprecipitationoftheNHRSisslightlylessthanthatoftheYHMY,andtheyearlyprecipitationvariationofthetworainyseasonsaresimilartoeachotherwithnoobviousincreasingordecreasingtrendinthe49years,butwithdistinguisheddecadalandinter-annualvariations.(3)Inpositiveprecipitationanomalyyears,theSouthAsianhighmovesmorenorthwardandmoreeastward,thewesternPacificsubtropicalhighislocatedmorenorthwardandwestward,andthesummermonsoonisstrongerthannormal,resultingintheconvergenceofthewarmandmoistsouthwesterlyairflowfromthewestsideofthesubtropicalhighandthecoldairfromthenorthsideofthenortheasttroughinNorthHuaiheRiverbasin.
简介:汽车路由解决方案是无所不在的,行人的解决方案也存在。而且,公共或商业的大楼正在变得更大,他们的内部结构的复杂性增加了。因而,对室内的路由答案的需要出现了。一些原型是可得到的,但是他们仍然缺乏语义上充实的建模(例如,存取限制,标签,等等)并且不对在复杂大楼里提供用户适应的长度最佳的路由合适。以前的途径认为简单房间,凹面房间,和走廊,而是象在房间内的巨大的房间和稳固的障碍里的不同区域那样的重要特征根本没被考虑,尽管如此的细节能增加航行精确性。由正式定义一张加权的室内的路由图,创造是可能的一详细说明并且为线路计算的用户适应的模型。定义的图也包含象房间标签那样的语义信息,门可接近性限制,等等。而且,在大楼内的单程的路径被考虑,以及三维的造分开例如,电梯或楼梯。层次结构与介绍的图模型一起也是可能的。