简介:这研究调查热带大西洋的吝啬的运动学的特征在东方在1月鈥揗arch(JFM)的骚乱,4月鈥揓une(AMJ),7月鈥揝eptember(JAS)和从1968鈥?的10月鈥揇ecember(OND)998。为每个季节,在3鈥?的这些骚乱的优先的轨道0天的乐队时期被计算并且spatialized,以及他们的联系波长,速度和主要时期,哪个在3鈥之间的谎言?天并且在6鈥之间?取决于轨道和季节的天。二条主要轨道在大西洋上被加亮。在OND和JFM期间,这二条轨道很好被分开并且在15掳S和12.5掳N附近在每个半球定位了。从AMJ,到JAS,这些轨道向北方移居;在JAS,他们沿着17.5掳N在北热带大西洋上合并进一个。联系波长地展出一个南方的坡度,与大波长(比4000km大)在赤道附近在5掳N和5掳S之间,并且在这个纬度乐队外面的更小的波长(在2500鈥?之间500km)。阶段速度也从12鈥被发现价值到展览poleward减少吗?ms?1。在北方大西洋轨道上,6鈥?天骚乱被发现从10月从1月发生到5月并且近似到12月。从6月到9月,3个鈥?天波浪统治摘要的活动。在南方大西洋轨道上,在5月和8月之间,摘要的可变性被3鈥?天骚乱,但是从1月主要向4月并且从到12月,两3鈥?天挥动的9月解释,6鈥?白天飘动能发生。关键词摘要的活动-非洲人在东方飘动-热带大西洋
简介:这篇论文调查在mei-yu和诺思大西洋海面温度异常(SSTA)之间的关系。结果证明他们显著地在十的时间规模上与对方被联系。mei-yu降水和mei-yu持续时间被重要十的可变性描绘。他们的十的部件密切在前面的冬季与诺思大西洋SSTA的一个三倍的模式被相关。回归分析证明冬诺思大西洋SSTA可以在东亚夏季风(EASM)循环上强加推迟的影响,在十的时间的mei-yu可伸缩。SSTA的坚持在这堂功课期间起一个重要作用。SSTA模式能从冬季坚持直到迟了的春天的三元组。春季SSTA可以使从西方欧亚大陆宣传到东亚的一列静止波浪火车激动并且在mei-yu上施加影响,这被建议。
简介:EarlystudiessuggestedthattheAleutian-Icelandiclowseesaw(AIS)featuresmultidecadalvariation.Inthisstudy,themultidecadalmodulationoftheAISandassociatedsurfaceclimatebytheAtlanticMultidecadalOscillation(AMO)duringlatewinter(February-March)isexploredwithobservationaldata.Itisshownthat,inthecoldphaseoftheAMO(AMOI-),aclearAISisestablished,whilethisisnotthecaseinthewarmphaseoftheAMO(AMO[+).ThesurfaceclimateoverEurasiaissignificantlyinfluencedbytheAMO'smodulationoftheAleutianlow(AL).Forexample,theweakALinAMOI-displayswarmersurfacetemperaturesovertheentireFarEastandalongtheRussianArcticcoastandintoNorthernEurope,butonlyovertheRussianFarEastinAMO{+.Similarly,precipitationdecreasesovercentralEuropewiththeweakALinAMOI-,butdecreasesovernorthernEuropeandincreasesoversouthernEuropeinAMOI+.
简介:AnalysisofArgofloattrajectoriesat1000mandtemperatureat950mintheNorthAtlanticbetweenNovember2003andJanuary2005demonstratestheexistenceoftwodifferentcirculationmodeswithfasttransitionbetweenthem.Eachmodehasapairofcyclonic-anticyclonicgyres.Thedifferenceisthelocationofthecyclonicgyre.Thecyclonicgyrestretchesfromsoutheasttonorthwestinthefirstmodeandfromthesouthwesttothenortheastinthesecondmode.TheobservedmodesstronglyaffecttheheatandsalttransportintheNorthAtlantic.Inparticular,thesecondmodeslowsdownthewestwardtransportofthewarmandsalinewaterfromtheMediterraneanSea.
简介:否定阶段的诺思大西洋摆动(NAO)事件通常比积极阶段的强壮,即,有NAO的阶段力量不对称现象。在这个工作,我们用有条件的非线性的最佳的不安(CNOP)探索NAO的这不对称现象方法与一三水平全球伪因地球自转而引起光谱模型。与冬季climatological流动强迫,CNOP方法识别在给定的起始的限制下面触发最强壮的NAO事件的不安,这被显示出。同时,NAO的阶段力量不对称现象特征能被揭示。由与线性结果作比较,我们发现不安自我相互作用的过程支持否定NAO事件的发作,它比在积极NAO发作期间强壮得多。结果在北方的冬季(DecemberFebruary)用climatological和带平均数的流动独立被获得19792006作为起始的基本状态。我们得出结论,基于NAO发作是一个非线性的起始值的问题的事实,那阶段力量不对称现象是NAO的一个内在的特征。
简介:ToexplorethepolysaccharidesfromselectedseaweedsofAtlanticCanadaandtoevaluatetheirpotentialanti-influenzavirusactivities,polysaccharideswereisolatedfromseveralAtlanticCanadianseaweeds,includingthreeredalgae(Polysiphonialanosa,Furcellarialumbricalis,andPalmariapalmata),twobrownalgae(AscophyllumnodosumandFucusvesiculosus),andonegreenalga(Ulvalactuca)bysequentialextractionwithcoldwater,hotwater,andalkalisolutions.Thesepolysaccharideswereana-lyzedformonosaccharidecompositionandothergeneralchemicalproperties,andtheywereevaluatedforanti-influenzavirusactivities.Totalsugarcontentsinthesepolysaccharidesrangedfrom15.4%(inU.lactuca)to91.4%(inF.lumbricalis);sulfationlevelwasashighas17.6%inapolysaccharidefromU.lactuca,whereasitcouldnotbedetectedinanalikali-extractfromP.palmaria.Forpolysaccharidesfromredseaweeds,themainsugarunitsweresulfatedgalactans(agarorcarrageenan)forP.lanosa,F.lumbricalis,andxylansforP.palmata.Inbrownseaweeds,thepolysaccharideslargelycontainedsulfatedfucans,whereasthepolysaccharidesingreenseaweedweremainlycomposedofheteroglycuronans.ScreeningforantiviralactivityagainstinfluenzaA/PR/8/34(H1N1)virusrevealedthatbrownalgalpolysaccharideswereparticularlyeffective.SeaweedsfromAtlanticCanadaareagoodsourceofmarinepolysaccharideswithpotentialantiviralproperties.
简介:AimtolinkingthevariabilityofdroughtinnorthwestChinatotheoceanicinfluenceofNorthAtlanticSSTsatthebackgroundofglobalwarmingandattheregionalclimatechangeshiftingstages,yeararidityindexvariationsinnorthwestChinaandsummerNorthAtlanticseasurfacetemperature(SST)variationsareexaminedforthe44aperiodof1961-2004usingsingularvaluedecomposition(SVD)analysis.ResultsshowthattheSSTanomalies(SSTA)intheNorthAtlanticinsummerreflectedthreebasicmodels.ThefirstSVDmodeofSSTpatternshowsadipole-likevariationwiththepositivecenterlocatedatsouthwestandnegativecenteratnortheastofextratropicalNorthAtlantic.AnditstronglyrelatestothepositivetrendinAIvariationinnorthwestChina.ThesecondcoupledmodesdisplaythecoherentpositiveanomaliesinextratropicalNorthAtlanticSSTandthemarkedoppositetrendofAIvariabilitybetweennorthandsouthofXinjiang.Inaddition,thelagcorrelationanalysisofthefirstmodeofSSTAandgeopotentialheightsat500hPavariationsalsoshowsthattheindicationoftheformerinfluencingthelatterconfiguration,whichresultinhigherairtemperatureandlessprecipitationwhentheSSTAintheNorthAtlanticOceaninsummermotivatedEurasiancirculationofEApattern,furthertoinfluencethewet-dryvariationsinnorthwestChinabytheocean-to-atmosphereforcing.
简介:AtmosphericInfraredSounder(AIRS)datashowthattheSaharanairlayer(SAL)isadry,warm,andwell-mixedlayerbetween950and500hPaoverthetropicalAtlantic,extendingwestwardfromtheAfricancoasttotheCaribbeanSea.TheformationsofbothHurricaneIsabelandTropicalDepression14(TD14)wereaccompaniedwithoutbreaksofSALairduringtheperiod1-12September2003,althoughTD14failedtodevelopintoanamedtropicalcyclone.TheinfluenceoftheSALontheirformationsisinvestigatedbyexaminingdatafromsatelliteobservationsandnumericalsimulations,inwhichAIRSdataareincorporatedintotheMM5modelthroughthenudgingtechnique.AnalysesoftheAIRSandsimulationdatasuggestthattheSALmayhaveplayedtworolesintheformationoftropicalcyclonesduringtheperiod1-12September2003.First,theoutbreaksofSALairon3and8Septemberenhancedthetransverse-verticalcirculationwiththerisingmotionalongthesouthernedgeoftheSALandthesinkingmotioninsidetheSAL,triggeringthedevelopmentoftwotropicaldisturbancesassociatedwithHurricaneIsabelandTD14.Second,inadditiontothereducedenvironmentalhumidityandenhancedstaticstabilityinthelowertroposphere,theSALdryairintrudedintotheinnerregionofthesetropicaldisturbancesastheircyclonic?owsbecamestrong.ThiseffectmayhavesloweddowntheformationofIsabelandinhibitedTD14becominganamedtropicalcyclone,whiletheenhancedverticalshearcontributedlittletotropicalcycloneformationduringthisperiod.The48-htrajectorycalculationsconfirmthattheparcelsfromtheSALcanbetransportedintotheinnerregionofanincipienttropicalcyclone.
简介:Thisstudydeterminesthepollution,fractionation,andecologicalrisksofsediment-boundheavymetalsfromcoastalecosystemsofftheEquatorialAtlanticOcean.ContaminationFactor(CF),pollutionloadindex(PLI),andgeoaccumulationindex(Igeo)wereusedtoassesstheextentoftheheavymetalpollution,whilethepotentialecologicalriskwasevaluatedusingtherisksassessmentcode(RAC)andH?kansonpotentialecologicalrisk.Theanalysisrevealedconcentrations(mg/g,dw)ofthecadmium(Cd),chromium(Cr),copper(Cu),nickel(Ni),andlead(Pb)insedimentsforwetanddryseasonsvaryfrom4.40-5.08,14.80-21.09,35.03-44.8,2.14-2.28,and172.24-196.39,respectively.Theresultsalsoshowedthatthemetalfractionationpercentagesintheresidual,oxidizable,andreduciblefractionsarethemostsignificant,whiletheexchangeableandcarbonateboundtracemetalsarerelativelylow.TheRACvaluesindicatenoriskforCdandNiandlowriskforothermetalsatallthestudiedsitesduringbothseasons.PotentialecologicalriskanalysisoftheheavymetalconcentrationsindicatesthatCdhadhighindividualpotentialecologicalrisk,whiletheothermetalshavelowriskatallinvestigatedsites.Themulti-elementalpotentialecologicalriskindices(R1)indicatehighecologicalriskinalltheecosystems.
简介:以前的研究建议在北热带大西洋(NTA)上的春天SST异例影响热带气旋(TC)在在下列夏天和秋天的西方的诺思太平洋(WNP)上的活动。现在的学习表明在春天NTASST和后面的夏天秋天WNPTC开始频率之间的连接不是静止的。后面的夏天秋天WNPTC开始频率上的春天NTASST的影响是在前弱、不足道,却在以后强壮、重要,1980年代末。在1980年代末前,在热带中央太平洋的NTASST导致异例的SST异例是弱的,并且在WNP上的大气的循环的反应不是强壮的。作为结果,在春天NTASST和后面的夏天秋天WNPTC开始频率之间的连接在以前的时期是不足道的。在1980年代末以后,相反,NTASST异例通过大西洋和平的teleconnection导致显著热带中央和平的SST异例。热带中央和平的SST异例进一步为WNPTC开始导致有利条件,包括垂直运动,中间水平的相对湿度,和垂直的带的风砍。因此,在NTASST之间的连接和WNPTC开始频率在最近的时期是重要的。进一步的分析证明interdecadal在在春天NTASST之间的连接变化,后面的夏天秋天WNPTC开始频率可能与在NTA区域上的climatologicalSST变化有关。