氣象專業英語第1頁/共48頁Newwords:Vector:向量Zonal緯向的latitude緯度Meridional:經向的longitude:經度Subpolar:副極地的subgridJetstream急流Reversal顛倒，反轉Westerly西風easterly東風Westerlies西風帶easterlies東風帶Retreat:復原，恢復；撤退withdrawEquator赤道ribbon帶狀物，strip;beltCoriolis科里奧利力Oceanographic海洋學的kinetic運動的第2頁/共48頁

大氣環流：一般是指具有世界規模的、大范圍的大氣運行現象，既包括平均狀態，也包括瞬時現象，其水平尺度在數千公里以上，垂直尺度在10km以上，時間尺度在數天以上。大氣大范圍運動的狀態。某一大范圍的地區（如歐亞地區、半球、全球），某一大氣層次（如對流層、平流層、中層、整個大氣圈）在一個長時期（如月、季、年、多年）的大氣運動的平均狀態或某一個時段（如一周、梅雨期間）的大氣運動的變化過程都可以稱為大氣環流。第3頁/共48頁

大氣環流通常包含平均緯向環流、平均水平環流和平均經圈環流3部分。①平均緯向環流。指大氣盛行的以極地為中心并繞其旋轉的緯向氣流，這是大氣環流的最基本的狀態，就對流層平均緯向環流而言，低緯度地區盛行東風，稱為東風帶（由于地球的旋轉，北半球多為東北信風，南半球多為東南信風，故又稱為信風帶）；中高緯度地區盛行西風，稱為西風帶（其強度隨高度增大，在對流層頂附近達到極大值，稱為西風急流）；極地還有淺薄的弱東風，稱為極地東風帶。第4頁/共48頁②平均水平環流。指在中高緯度的水平面上盛行的疊加在平均緯向環流上的波狀氣流（又稱平均槽脊），通常北半球冬季為3個波，夏季為4個波，三波與四波之間的轉換表征季節變化。③平均經圈環流。指在南北-垂直方向的剖面上，由大氣經向運動和垂直運動所構成的運動狀態。通常，對流層的徑圈環流存在3個圈：低緯度是正環流或直接環流（氣流在赤道上升，高空向北，中低緯下沉，低空向南），又稱為哈得來環流；中緯度是反環流或間接環流（中低緯氣流下沉，低空向北，中高緯上升，高空向南），又稱為費雷爾環流；極地是弱的正環流（極地下沉，低空向南，高緯上升，高空向北）。

第5頁/共48頁控制大氣環流狀態的基本因子①大氣本身的特殊尺度（準水平）②太陽輻射隨緯度分布的不均勻性（三圈環流）③地球自轉（準地轉）④地球表面的不均勻性（海陸分布、陸地起伏）⑤地面摩擦（東西風維持）第6頁/共48頁第7頁/共48頁第8頁/共48頁第9頁/共48頁第10頁/共48頁赤道無風帶是指赤道附近南、北緯5°之間的地帶。這里太陽終年近乎直射，是地表年平均氣溫最高地帶。由于溫度的水平分布比較均勻，水平氣壓梯度很小，氣流以輻合上升為主，風速微弱，故稱為赤道無風帶。它控制下的天氣特點是氣壓低、濕度大、多云、多雷暴，是海上航行時要避開的區域。

第11頁/共48頁第12頁/共48頁第13頁/共48頁第14頁/共48頁第15頁/共48頁第16頁/共48頁第17頁/共48頁第18頁/共48頁a第19頁/共48頁b第20頁/共48頁第21頁/共48頁第22頁/共48頁第23頁/共48頁第24頁/共48頁第25頁/共48頁第26頁/共48頁第27頁/共48頁第28頁/共48頁第29頁/共48頁fell第30頁/共48頁P1:①Thegeneralcirculationcomprisesthemovementsoftheatmosphereonaworldwidescale.②Sinceitisusuallystudiedbymeansofdataaveragedoverseveraldays,sothatminor,localorday-to-dayirregularitiesaresmoothedout,anymodelofthegeneralcirculationmustbegeneralized,andcannotincludeverymanyshort-livedfeaturesofimportanceforlocalweather.③Thegeneralcirculation

istheoverallpatternthatmustobviouslyaffectlocalweatheratsometimeoranother,directlyorindirectly,andis

inthissensethegreatestsingleterrestrialcauseofclimateandweather.第31頁/共48頁P2:①Technically,thegeneralcirculationmaybedefinedasthemeanthree-dimensionalpatternofthemeteorologicalelements,plusthe“turbulence”,theoscillationorperturbationsofthemeanpattern,providedbychanging,day-to-daysynopticweatherpatterns.②Itsbasicfeaturesmaybedescribedintermsofglobal,seasonalvectormeanwindsasafunctionofheight,ortheymaybederivedbyapplyingthegeostrophicwindrelationtomeanspressure-contourcharts.第32頁/共48頁P3:①Thethree-dimensionalaspectsofthegeneralcirculationasactuallyobservedmustbeparticularlyemphasized.②Forcomparativepurposes,itisconvenienttoseparatethezonal(east-west)andmeridional(north-south)componentsofthemeanmotionforthenorthernhemisphere.③Themeanmeridionalcirculationisaboutameterpersecondinthelowerandmiddlelatitudesthroughoutasubstantialdepthoftheatmosphere:thisisamuchweakercirculationthanthezonalone,butcanneverthelesscreateordestroymomentumattherateof10mpersec.第33頁/共48頁P4:①Thesimplestmodelthatincorporatesthemainfeaturesoftheobservedmeanmeridionalisgiveninthefigures(omitted).②Thethreekindsofcellsareinthetroposphereineachhemisphere:theHadleycellsinthetropics,theFerrelcellsinmiddlelatitudes,andtheweaksubpolarcellsbeyondthese.③AngularmomentumisinjectedintotheFerrelcellsasindicatedbythearrows,andislatercarrieddownwardbysmallconvectiveeddies.④ConvectionismostintenseinlowlatitudesandthusforequilibriumtooccurtheHadleycellsmustrotatefasterthantheFerrelcells.第34頁/共48頁全球大氣環流示意第35頁/共48頁第36頁/共48頁P5:①ThemodeldevisedbyPalmen

takesintoaccounttheexistenceofjetstreams,whicharethedominantfeaturesoftheactualcirculation.②ObservationshowsthattheHadleycells,whicharedirectlydrivenbyheat,arethemostimportantsingleelementsofmeantroposphericcirculation,buttheFerrelcells,drivenbyfrictionwiththeHadleycells,probetobemoresignificantthanPalmenenvisaged.第37頁/共48頁P6:①Anindependentcirculationisgeneratedbyheatingandcoolinginthestratosphere,downtoabout10mb.②Stratosphericwindsrevealremarkablereversalsindirection.③Astratosphericmonsoonoccursinthenorthernhemisphere:westerlieschangetoeasterliesinAprilabove10mb,thereversalproceedingdownwardandsouthwardfromthepolarregions,reaching100mbinlateMay.④Easterliesprevailabove100mbfromMaytoAugust.⑤InlateAugustandearlySeptember,theseeasterliesrevertbacktowesterlies.第38頁/共48頁P7:①OverNorthAmericainApril,stratosphericpolareasterliesareseparatedbythemiddle-latitudewesterliesfromthetropicaleasterliesoftheloweratmosphere,whichmovenorthwardinthemonth.②ByJuly,easterliesprevaildowntoatleast15kminlowlatitudes,to20kminmiddlelatitudesandto15-17kminpolarlatitudes.③BySeptember,thepolarandtropicaleasterliesbeginretreatingtotheirminima,inNovemberandDecember,respectively.④Ingeneral,thepictureat10mbisofaslow,steadytransitionfromsummereasterliestowinterwesterlies,butduringJanuaryandFebruary1958thissimplepatternbrokedowninaverycomplexmanner.第39頁/共48頁P8:①GeneralmodelsoftheupperatmosphericcirculationhavebeenproducedbyKelioggandSchilling(1951),Murgatroyd(1957),andBatten(1961).②AccordingtoBetten’smodel,themajorcenterofwesterlywindsisinthewinterhemisphere,althoughthesewindsalsocrosstheequatorintothesummerhemisphere.③Easterliesoccurinspringinthelowerionosphere,buildingdownfromthemesosphereaswesterliesdevelopaloft;inturn,thewesterliesthenbuilddownaseasterliesdevelopaloft.④Smalleasterlycentersoccurinthelowermesosphereinlatewinterandspring.⑤ThestratospherewindsabovethePacificequatorialregionareextremelyvariable.第40頁/共48頁P9:①ImportantelementsofthestratosphericcirculationincludetheBersonwesterliesandtheKrakatoaeasterlies.②Theformer,firstdiscoveredat50to60mbovercentralAfrica,butnowknowntooccuranywhereupto10mb,formacontinuousribbonaroundtheequator:thewesterliesandeasterliesalternate,onehalf-cyclebeing12to15months.③TheKrakatoaeasterliesoccurat25mb:theirexistencewasfirstinferredfromthemovementofvolcanicdustafterKrakaroaeruption.④RadarwindobservationsnowindicatethatKrakatoawesterliesalsooccur.第41頁/共48頁P10:①Thegeographicalimportanceofthesestratosphericwindsisthattheymakeanysimple,intuitivemodeloftheatmosphericcirculationuntenable.②Insuchamodel,therotationoftheEarthfromwesttoeastisassumedtodragthelowerpartoftheatmospherewithit,impartingawesterlymotiontotheselayers.③Thusslightvariationsinthemomentumofthewest-eastrotatingatmospherewouldbeinterpretedattheEarth’ssurfaceasindicatingwindsapparentlycomingfromdifferentdirections.④Alocalexcessofmomentumintheatmosphere,causingthelattertomovemorerapidlyfromwesttoeastthantheEarth’ssurface,wouldbedescribedasawestwind.⑤Alocaldeficitofmomentum,causingtheatmospheretomovelessrapidlythantheEarth’ssurface,wouldgiverisetoaneastwind.第42頁/共48頁P11:①Recentobservationsindicatethatthehighatmospherecontainsmanycirculationfeaturesthatcannotbeexplainedbyasimpleintuitivemodel.②Thus,changesintherotationofSputnik3canbeexplainedbytheexistenceofastrongwesterlywind,accompanyingtheEarth’srotation,butwellaboveanyregionofpossiblefrictionaldragwithitssurface.③Slowoscillations,representingabalancebetweeninertiaandCoriolisforcesandstaticstability（靜力）,havebeenmeasuredbyradarsondetheodolites（經緯儀）atCrawley.④Theyhaveperiodof12hoursorso,andareduetodisturbanceswithverticalandhorizontaldimensionsof1kmandseveral100km,respectively.⑤Thecomplexityofdataforthehighatmospherehasmadeitnecessarytosplitthecirculationsobservedintomathematicalcomponents.第43頁/共48頁P12:①Thecirculationmodelsdiscussedsofarhavebeenondiffusion.②InBrewer’smodel,basedonthediffusionofozoneandwatervapor,airrisesthroughtheequatorialtropopause,whichactsasacoldtrapowingtoitslowtemperature(around80℃).③Thecold,dryairthenmoveshorizontally,finallysinkinginmiddleandhighlatitudes.④AccordingtoDobson’smodel,ozone-enrichedairarrivingviaBrewer’smeridionalcirculationisstoredinthestratosphericpolar-nightjet,i.e.,inthecoldpooloverthewinterpole.⑤Fromhere,itgraduallysinksintothelowerstratosphereattemperatelatitudesinlatewinterandspring.第44頁/共48頁P13:①InSpar’smodel,whichisbasedonthediffusionofradioactivedebris（放射性碎片）,themainexitforairfromthestratosphereisthroughthegapinthetropopause,inwhichturbulentmixingtakesplace.②Moremixingtakesplaceinthepolarstratosphere(particularlyinwinter)thanelsewhere,andmuchlessmixingintheequatorialstratospherethanintheBrewer-Dobsonmodel,whichdescribesonlyonepartofthewholecirculation.

③ThehighestpartsoftheBrerrer-Dobsoncirculationreach80,000feet;abovetheatmospherewasenvisagedbyBrewerandDobsonasstagnantregionismoist,andmeridionaltransferisaffectedbysmall-scaleturbulentdiffusion.④Theheightofthetransitionfrommeridional-circulatingtomeridional-stagnantairvariesbothintimeandinlatitude.第45頁/共48頁P14:①IntheGoldsmith-Brownmodel,risingairattheequatordoesnotreachgreatheights,butturnspolewardalmostimmediatelyabovethetropopause.②Themeridionalcirculationisrapidjustabovethetropopause,theairtakingslightlymorethantwomonthstoreachtemperatezones.③Theupperflowismuchslowe