《海洋物理学》期末复习资料

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注：以上所有页码均为老师PPT转换成PDF文档(2014DP014end.pptx)上的页码，

页码与考点不应不是十分准确但大致在上述页码附近。

由蜗牛不会飞一王云辉于2015年1月6日整理

注：

红字部分表示答案；

蓝字部分表示老师强调的问题；

9-14章内容李老师说仅考察选择题和填空题，所以这几章有些组week4里面的

的题目没有做，对章节内容进行了总结：见：

1缜J诙。老磔磔2015/1/K616:07文件夹

13豆-南冰洋不会飞3缰2015/1/1616:02文件夹_________________________|

Week1(12.1-12.4)Questions

Chapterl-3

1.Whatpropertiesofseawaterdetermineitsdensity?

Ans:温度，盐度，压力

2.Whatisthepressureatthebottomoftheoceanrelativetoseasurfacepressure?Whatunit

ofpressureisverysimilarto1meter?

Ans:水质量引起的重力；dbar

3.Whatistheappropriatetemperaturescaletouseforheatcontent?

Ans:K,开尔文

4.Whathappenstothetemperatureofaparcelofwater(oranyfluidorgas)whenitis

compressedadiabatically?Whatquantitydescribestheeffectofcompressionon

temperature?Howdoesthisquantitydifferfromthemeasuredtemperature?(Isitlargeror

smalleratdepth?)

Ans:

温度升高；potentialtemperature,位势温度；位温小于现场测量温度

5.Whatarethetwoeffectsofadiabaticcompressionondensity?Whatquantityisusedto

minimizetheeffectofcompressionondensity?

Ans:

分子间距减小，使密度增加，而温度升高使密度减小；potentialtemperature,位势温度

6.Whatissalinity?

Ans:

1KG海水中溶解的盐的克数

7.Whatuniquepropertiesofseawaterarisefromnon-linearityintheequationofstate?

Ans:压力

8.Whatarethesignificantdifferencesbetweenfreezingpurewaterandfreezingseawater?

Ans:

海水冰点和它最大密度时的温度并不固定，取决于海水中所含的盐分的多少；低于淡水

的冰点

9.Freshwaterhasadensitymaximumatatemperatureabovethefreezingpoint,whichallows

icetofloat.Isthisalsotrueforseawater?Whydoesiceformedfromseawaterfloat?

Ans:

不是的；海冰随冰龄的增加，冰中的卤素析出，发生盐析，密度变小，所以漂浮

10.Whyisthereasoundspeedminimuminthemiddleofthewatercolumn?

Ans:

随深度增加，压力升高，声速增加，而随深度增加，温度下降，声速减小，压力升高引

起的声速增加被温度降低引起的速度降低所抵消，导致中层存在速度最小的点。

Chapter4

1.Howdeepisatypicalmixedlayerifmixedbywind?Howdeepcanitreachifdrivenby

cooling?

Ans:

不超过100-150米；几百米甚至达1000米

2.Whatarethetypicalverticaltemperatureandsalinityprofilesinthesubtropicalandsubpolar

regionsoftheNorthPacific?

Ans:

北太平洋亚热带温度垂向分布；北太平洋亚热带盐度垂向分布；北太平洋副极地温度垂向

分布；北太平洋副极地盐度垂向分布

Potentialtemperature(℃)

102030010

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FIGURE4.2Typicalpotentialtemperature(C)/depth(m)profilesfortheopenoceanin(a)thetropicalwesternNcrth

Pacific(5"N),(b)thewesternandeasternsubtropicalNorthPacific(24N),and(c)thewesternsubpolarNorthPacific

(47°N).CorrespondingsalinityprofilesarcshowninFigure4.16.

FIGURE4.16Typical

salinity(psu)profilesfor

thetropical,subtropical,

andsubpolarregionsof

tineNortiiPacific.Corre-

spcxidingtemperature

profilesareshownin

figure42

15C0

2000-

3.Whatarethedominantregionsofnetevaporationintheocean?

Ans:

Insubpolarandhighlatitudes,wheresurfacewatersarequitefreshandalsocold,netevaporation

dominatestheverticalstability.

4.WhatarethekeycomponentsoftheMixedLayerheatbudget?

Ans:

rateofinflowofsolarenergythroughtheseasurface(shortwaveradiation)

netrateofheatlossbytheseaaslongwaveradiationtotheatmosphereandspace(backradiation)

rateofheatloss/gainthroughtheseasurfacebyconduction(thesensibleheatflux)

rateofheatloss/gainbyevaporation/condensation(thelatentheatflux)

rateofheatloss/gainbyawaterbodyduetocurrents(theadvectiveterm)

5.1stheNorthAtlanticOceansaltierorfresheronaveragethanthePacific?Why?

Ans:

Saltier.BecausetheexcessevaporationandinternaldensewaterformationoftheNorthAtlantic

Ocean.

6、Whatregionsoftheoceanarecharacterizedbylargedifferencesfromsummer

towinter?Whatregionshavetheleastseasonalvariability?

Ans:

1)夏天到冬天差异最大的区域

Muchofthegeographicvariationinpropertiesintheoceansandatmosphereoccursinthe

north-south(meridional)direction.Themostmarkedseasonalchangestakeplaceinthe

temperatezones(approximately30-60NorS)

主要发生在南北方向。温带区域。

2)季节性变化最小的区域

Propertiesareoftenmuchmoreuniformintheeastwest(zonal)direction.

主要发生在东西方向。

7、Pleasedescribethetwoprocessesthatmaintainthethermocline.

Ans:

描述维持温跃层的两个过程

Theregionofhigherverticaltemperaturegradient(rateofdecreaseoftemperaturewith

increasingdepth)iscalledthethermocline.

温跃层是温度随着深度的增加急剧下降的一层。

1、垂直过程：影响温跃层的垂直过程的是来自海洋表面热量的向下传输和上升流或者是下

降流。一般认为，上层的水是最温暖的，温度通过扩散作用向下传输，上层水和下层水的温

差最后会消失。然而，深层的冷水(deepercoldwater)来自高纬度地区的海洋表面，这些

水保持了温暖的表面水和寒冷的深层水的温差。这种向下的热量的垂直扩散由来自深层冷水

的上升流的平衡。在温度的垂直横切面上呈指数形式。

2、该过程具有更加水平、绝热、互补的特性。Iselin发现在北大西洋的南北走向狭长带的表

面的温-盐关系和在垂直的T-S关系类似。他假设在亚热带的温跃层的水来源于远离北部的表面

水，当他们向南移动时，较冷的表面水俯冲(subduct)在较热的表面水的下层，这样建立了温

跃层的温度、盐度、以及密度的结构。这个过程是绝热的，不需要混合或是上升流等。

Week2

Chapters

1.Whatfactorsdeterminetheheatbudgetterms,Qs,Qb,QeandQh,respectively?

Makecleartheimpoitanceofeachfactorofeachterm.

Ans：QT=Qs+Qb+Qh+Qe+Qv

式中：QT代表总的热流率(增加或者失去)thetotalrateofgainorlossofheatofthebodyof

water

Qs代表太阳能辐射热流(入射短波辐射)Solarheatflux

Qb代表长波反射辐射Longwavebackradiation

Qh代表显热热流Sensibleheatflux

Qe代表潜热热流Latentheatfluxes

代表平流热流Advectiveheatflux

反射率Q和太阳高度角0影响Qs

海洋绝对温度，表面水蒸气分压、云层覆盖率有无冰雪覆盖影响Qb

Qe=Fe•L=pCeU（Cjs-是潜热换热系数,④是距海面10m高处风速,

qs是在海表面温度下的98%的饱和湿度，qa是海表面温度下的实际湿度，L是蒸发潜热。

Qh=PCCh«（T-（T+yz））

pPSCap是传热系数，Ch是显热换热系数，u是距海面

10m高处风速，Ts是海洋表面温度，Ta是z高度处空气温度，丫是绝热损失效率。

2.Whataretherangesofthemagnitudeofthefourterms?Foreachterm,please

specifythefocationandvalueofthemaximumandminimumcenter;basedon

Fig.5.17-5.21.

Ans:

短波辐射在近极地地区是50~150W/nf,在亚热带和热带地区是150~250W/nf,最大值出现

在热带的太平洋地区以及阿拉布半岛附近的热带印度洋西部，最小值出现在两极地区。

全球的长波辐射损失的中心大概在50W/nf,因为长波辐射的大小主要取决的物体的绝

对温度，长波辐射在亚热带云层覆盖较少的地区达到最大值。

潜热换热相对比较强烈，有超过100W/nf的热量损失，最大值出现在亚热带的低云层覆

盖率的区域，这些地方往往有干空气从高处沉降。潜热换热在温度高的地方更强烈，两极地

区最弱。

显热换热通常具有最小的数量级，（T5W/nfF）左右），最大值出现在太平洋和大西洋的西

北部。在南极洲附近显热换热出现了正值，但是非常小。

Chapter6I.NameatleastthreeObservationalmethods

Ans:

Researchships（海洋研究船）；autonomoussamplerssuchasfloatsanddriftersandofverticalprofiles

collectedfrommerchantships（自动采样器，如浮标和由商船采集的水体垂直剖面数据）；Satellites

andsensors（卫星和传感器）

2.NameatleastthreeDataanalysismethods

Ans：

Leastsquaresmethods（最小二乘法）；Inversemethods（反演方法）；oceanographicdataassimilation

（海洋数据同化）；optimummultiparameteranalysis（最优多参数分析）；

Chapter7

l.Workouttheperiodofinertialoscillationsatthenorthpole,30N,equator;andsouthpole.（分

Ans:

别计算北极，30N,赤道，南极的惯性振荡周期）

答：仅在Coriolis力作用下的水平运动必然是在平衡位置附近的振动,这种振动称为惯性振

动。

公式du/dt-fv=O(1)

dv/dt+fu=O(2)

由(1)式两边对t求导，得dSj/dtZ-fdv/dtR(3)

由(2)式得但dv/dt=-fu,代入(3)式，得

du/dtJ+f2u=0(4)

所以惯性振荡的圆频率为f,则周期为

To=2n/f=2贝/2(wsin<!>)=n/(wsin6)

仅在北极点和南极点，地球自转角速度w=O,f=O,无惯性振荡，T°=0

除两极外，w=2n/(24h)=n/12h1

在90N和90S,To=Jt/(Ji/12h'*sin90)=12h

在北极圈与南极圈,6=66.5,To=Jt/(it/12h'*sin66.5,)=16.4h

所以南北极范围惯性振荡周期为12-16.4h之间,纬度越高周期越小。

在30N,To=n/(n/12h'*sin30)=24h

在赤道，f=0,无惯性振荡，T,)=0

2.Ingeostrophicflow,whatdirectionistheCoriolisforceinrelationtothepressuregradientforce?

Whatdirectionisitinrelationtothevelocity?(在地转流中,相对于压力梯度力,科式力的方

向是？相对于速度方向，科式力的方向又是？)

Ans:

压力梯度力驱使水从高压力区流向低压力区，科式力与压力梯度力方向相反，形成静力平衡。

相对于速度方向，在北半球，科式力向右，在南半球，科式力向左。

3.Whatisa"levelofnomotion"?Whywoulda"levelofknownmotion"beabetterchoiceforthe

samekindofcalculation?(Whatcanweactuallycomputeaboutthevelocitystructuregiventhe

densitydistributionandanassumptionofgeostrophy?)(什,么叫"无运动层(动力零面)”?为

什么使用“已知运动层”会更适合计算？(通过密度分布和地转流假设，我们怎样模拟涡旋

结构？)

Ans:

(1)无运动层：在一定深度，水平压力梯度场认为是均匀的。(alevelofnomotion,adeep

horizonalongwhichthepressurefieldisassumedtobeuniform)或者说某一层流己知，允许从

相对流推导绝对流。

涡旋结构遵循公式并且可简化成只含有一个变量的公式

(2)u(z)=F(u*,v,z),u(z)u*=F(u*zv)z

由于地转流的存在，把科氏力加入该公式，u(z)u*=F(u*zv,fzu*)o因为有密度差异的存在

a”_+gapdvgap

所以在垂直和水平方向上的u,V都有差异，即az-pofdy(及—一而菽.。

4.Namethethreecontributingfactorstopotentialvorticity.(MH；位涡的三个影响因素)

Ans:

«+/)DH=o

whichcanbewritten:

~Si卷)=0

Thequantitywithintheparenthesesmustbeconstant.Itiscalledpotential

vorticityII.Potentialvorticityisconservedalongafluidtrajectory:

PotentialVorticity=n、〃/(12.9)

ThisrotationTistheplanetaryvorticity.

WhereHisthedistancefromtheseasurfacetothebottom.

Relativevorticity；isthevorticityduetocurrentsintheocean.

Mathematicallyitis:

C三curl.V=药一

5.HowdoesEkmanpumpingconnecttotheSverdrupinteriorflow?Explainusingpotentialvorticity

arguments?(埃克曼抽吸与Sverdrup流有什么关联？用位涡平衡加以解释)

Ans:

位涡平衡“V=faw/az.以北半球为例，在亚热带区域因艾克曼幅合，从而导致

水体产生向下的速度，在海洋内部相对涡度很小，所以行星涡度必须减小，从而导致了向赤

道方向的副热带涡流。同理，在北半球近极地区域因上升水流产生向极副极地涡流。简而言

之，Sverdrup输运并是因艾克曼抽吸(泵)引起行星涡度变化从而产生的这种副热带涡流和

副极地涡流的综合结果。

Chapter8

l.Asurfacegravitywavehasawavelengthof156meters,aperiodof10seconds

andaheightof8m.IttravelsindeepwaterandpassesafixedpointP.

•⑴Whatisthephasespeed?Whatisthewavesteepness?

•(2)WhatisthedisplacementatPat(a)20secondsafterthecresthas

passed?(b)30secondsafterthecresthaspassed?(c)35secondsafterthe

cresthaspassed?

•(3)Whatisthedisplacementatasecondpoint,Q,whichis117meters

awayfromPinthedirectionofwavepropagation:(a)whenthe

displacementatPiszero?(b)whenthedisplacementatPis-8meters?(c)

2.5secondsafteratroughhaspassedP?

•(4)Letusassumethattheseasurfaceisflatbeforeawavecrestarrives

atpointPattimet=0.[a]Drawatimeseries(record)ofsurface

displacementatpointPuntilt=30seconds(b)Drawatimeseries(record)

ofsurfacedisplacementatpointQuntilt=30seconds,(c)Drawapictureof

surfacedisplacementsbetweenpointsPandQatt=15seconds.

2.Swellwaveshavetheremarkableabilitytotravelfarfromtheirplaceoforigin.

AgroupofswellwavesweregeneratedbyawindstormintheAtlanticOcean

wherewateris1000metersdeep.Theyhaveawaveperiodofroughly20seconds,

awavelengthofabout624metersandawaveheightof4meters.Theseswell

wavesmovetowardstotheEastCoastoftheU.S.

•⑴Calculatethewavephasespeedinwatersofdepthsof500,100and

10meters.

•(2]Letusassumethattheswellwavesdonotbseanyenergyduring

theirtraveltowardsthecoast.Whatisthewaveheightinwatersof500,

100and10metersdeep?(Hintthegroupvelocityinwatersofany

depthh).

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Week3

大西洋：

1.NamethemajorcurrentsintheAtlanticoutsideofthetropics(northof15Nandso

uthof15S).

Ans:

Thesubtropicalgyresincludeeasternboundarycurrentupwellingsystems:the

CanaryCurrentsystemintheNorthAtlanticandBenguelaCurrentSystem(BCS)in

theSouthAtlantic.

•DeepWesternBoundaryCurrents

•NorthAtlantic'sGulfStreamandNorthAtlanticCurrent

•AntarcticCircumpolarCurrent

•Malvinas(orFalkland)CurrentandAgulhasCurrent

2.ExplainwhytheN.Atlantic'ssubtropicalgyrehastwodifferentwesternboundaryc

urrents.

Ans:

ThenorthwardwesternboundarycurrentsforthisgyreincludetheGulfStream

SystemandtheNorthAtlanticCurrenteastofNewfoundland.TheSouthAtlantic's

subtropicalgyreextendswellsouthofAfrica.Thesouthwardwesternboundary

currentforthiscirculationistheBrazilCurrent.

3.ExplainwhytheN.Atlantic'ssubpolargyrehastwodifferentwesternboundarycur

rents.

Ans:

TheNorthAtlanticCurrent(NAC)istheeastwardflowonthesouthern

sideofthesubpolarregion;branchesoftheNACflownortheastwardtowardtheNordic

Seas.

4.WhereistheAzoresCurrent?

Ans：

TheremainderoftheGulfStreamcontinueseastwardandsouthward,splittinginto

twobranches,theonefarthersouthat35N,calledtheAzoresCurrent

5.ThesubpolargyrecirculationismorecomplicatedthantheN.Pacific'ssubpolargy

recirculation.ThisgetsintothenextlectureondeepAtlanticwatermasses,butcanyo

usurmisewhythesurfacecurrentsoftheN.Atlanticsubpolargyreflowtothenorthe

astanduptotheareawestofNorway;whilethedeeperflowintheN.Atlanticsubpola

rgyrejustfollowsalongthebathymetryinacycbnicpattern?

Ans:

Theenergeticwinddrivencirculationoftheupperoceandecreasesinenergywith

depthandalsochangesshapelaterally,Bottomintensificationisanindicationthata

givenflowhasasignificantthermohalinecomponent.Itisnotstraightforwardto

distinguishwind-driveno

andthermohalinefeaturesintheNorthAtlantic'ssubpolargyre

6.WhatregionsoftheNorthandSouthAtlanticaredominatedbysubduction?How

mightyoufigureouthowdeepthesubductionreaches?

Ans：

IntheNorthandSouthAtlantic.TheeastwardNACinthewesternNorthAtlantic

formsthesouthernsideofthesubpolarcirculation,aswellasthenorthernsideof

thesubtropicalcirculation.TheNACthensplitsintoapartthatturnssouthwardto

thesubtropics,includingthePortugalCurrent,andtwonortheastwardbranches.The

subtropicalbranchisassociatedwithtypicalsubtropicalgyresubduction.The

northeastwardbranchesarepartofthesubpolarcirculation.Thefirstturns

northwardintotheIcelandBasineastoftheReykjanesRidgeandthesecondturns

northwardintoRockallTrough,closetotheeasternboundary.Astheyreachthe

Iceland-FaroeRidge,bothbranchesjointheIceland-FaroeFrontandmove

northwardintotheNorwegianAtlanticCurrentintheNordicSeas.

NorthAtlanticSubtropicalbranchreachesUpper0-400m.

SouthAtlanticSubtropicalbranchreachesUpper0-300m.

7.HowdoestheequatorialcurrentsystemdifferfromthatinthePacific?

Ans：

Attheequator,theAtlanticextendsfrom45°Wto10°E,adistanceofabout6000

km.BecausetheequatorialPacificismorethantwicethiswide,the

wind-drivenequatorialcurrentsystemsdifferinsomerespects,especiallyinstrength.

ThetropicalAtlanticisbisectedbytheMAR,whichhasamajoreast-westfracture

zonedtheRomancheFractureZonedclosetotheequator.Intheeast,thetropical

regionislimitedtothenorthbythecurveoftheAfricancoastline.

8.WhatisSubtropicalUnderwater?

Ans:

Betowthewarmtropicalsurfacewater;thenearlylinearT-SrelationinboththeNorth

AtlanticandSouthAtlanticiscalledtheCentralWater.Thisisthemainpycnoclineof

thesubtropicalgyreofeachocean.CentralWatersoriginatefromsurfacewatersthat

subductfromdifferentlocationsandhavearangeofdensities.TheNorthAtlantic

CentralWaterissaltierthantheSouthAtlanticCentralWater;andis,infact,the

saltiestCentralWaterofallfiveoceans.WithintheCentralWater;subductedhigh

salinitysurfacewatercreatesanear-surfacesalinityminimumcalledSubtropical

Underwater(STUW).Thisisanoisypresenceataround25℃inthissample-based

T-Srelation,butismuchclearerintheverticalsections.

NorthPacificcirculation(太平洋)

1.Namethemajorsurfacecurrentsnorthofabout15NinthePacific.

Ans:

Kuroshio,NorthPacificCurrent.

2.WhatdrivesthelargegyresoftheNorthPacific?Wind.

Describethedynamictopographydistributionthatisassociatedwiththegyres.

Ans:

Nearthebottomtherearealsoadditionalcurrentsassociatedwiththetopographyand

globalthermohalineforcing(weakupwelling).

Outsidethetropics,thedeepflowpatternsareinfluencedbytheoverlyinggyres,the

underlyingtopography,andtheDWBCs.

Describetheverticalstructureofthesubtropicalgyre.(Whathappenstoitsstructure

withdepth?)

Ans:

Thesubtropicalgyreshrinksspatiallywithdepth.Likeallsubtropicalgyres,itshrinks

towardthemostenergeticpartofitssurfaceflow:westwardtowardthewesternboundary,

andnorthwardtowardtheKuroshioExtension.TheKuroshioExtensionextendstothe

oceanbottom.

Thegyreshrinkagefromtheseasurfacetoabout200mdepthisdramatic.The

boundarybetweeneastwardandwestwardflowsshiftsfromsouthof20Natthesea

surfaceto25-30Nat200m.

TheC-shapeofthewesterngyre,whichincludestheSTCC,disappearsby200m.

Ontheotherhand,theKuroshioandKuroshioExtensiondonotshift.At1000el500m

depth,theanticyclonicsubtropicalgyreisfoundentirelyinthewesternNorthPacificnear

theKuroshioandKuroshioExtension.

3.WhereistheKuroshio?HowdeepdoestheKuroshioExtensionreach?

Ans:

TheKuroshioarisesatthewesternboundarywherethewestwardflowoftheNEC

splitsatabout15Nintonorthwardandsouthwardboundarycurrents:theKuroshioand

MindanaoCurrent,respectively.TheKuroshiocontinuesnorthward,turnstofollowthe

southcoastofJapan,thenseparatesandflowsouttothemid-subtropicalgyre.

AftertheKuroshioseparatesfromthewesternboundaryandflowseastwardintothe

NorthPacific,thecurrentisreferredtoastheKuroshioExtension.

WheredoesitbecometheKuroshioExtension?

TheKuroshioExtensionextendstotheoceanbottominthedeepestwater

downstreamoftheseparationpoint,with10cm/secvelocitiesevenatthebottomo(about

6000m)

WhatisthecirculationjusttothesouthoftheKuroshioExtension?

TheKuroshioExtensionextendstotheoceanbottominthedeepestwater

downstreamoftheseparationpoint,with10cm/secvelocitiesevenatthebottomo(about

6000m)

DoestheKuroshioExtensiontransportvarywithlongitude?

Yes,TheKuroshioExtensionishighlyunstable.ltmeandersandproducesrings

whenthemeanderspinchoff.Themeandershavesome-whatpreferredlocationso

4.WhatisthedirectionofmeanflowthroughBeringStrait?Howdeepisthestrait?

Ans:

North-wardthroughtheBeringStrait,About1636m.

5.Whatisthesurfacestructurethatseparateswatersofthesubtropicalandsubpolar

gyres?Whatisitsimportanceforfisheries?

Watermassproperties

Ans:

Thedensityisthelowestwhenitstemperatureis4℃.Itsdensitydecreaseswhenits

temperatureincreasesabove4℃.Theothersituationistheopposite.

Itcantakelotsofnutritionfromthebottomtothetop,whichisusefulforfisheries

6.Howdoeswatergetfromthesurfacetobelowthesurfaceinthesubtropicalgyre?(

Whatissubduction?)Whyisthereatongueofhightritiumandlowsalinityextending

westwardabngthesouthernlimbofthesubtropicalgyre?

(书上找不到)

7.WhatisSubtropicalModeWater;whereisitfound,andwhatisapossiblemechanis

mforformingit?

Ans：

(l)SubtropicalModeWater(STMW)isanotherexampleofawatermasswitha

simpleverticalextremum;inthiscaseitsthickness(verticalhomogeneity)is

comparedwithwatersaboveandbelowit.

(2)Itisfoundineachocean'ssubtropicalgyre.

(3)STMWoriginatesinathicksurfacewintermixedlayerthatisthenadvecteddown

alongisopycnalsintotheoceaninterior.STMWretainsitssignatureofrelative

thickness,justastheMWretainsitssignatureofhighsalinity.Slowmixingwithinthe

oceaninterioreventuallyerodestheseextrema,buttheypersistfarenoughfromtheir

sourcestobeusefultracersofflow.

8.WheredoesthedensestventilationintheNorthPacificoccur?Whatprocessesare

importantinthisventilation?Howisthisrelativelydenseventilationrecognizedon

mapsofoxygenandsalinity?

Ans:

(l)NorthPacificIntermediateWater

(2)ThemaindirectventilationprocessforNPIWisbrinerejectionduringseaice

formationinacoastal(latentheat)polynyainthenorthwesterncomeroftheOkhotsk

Sea("NWP"inFigure10.34b).Polynyasallalongtheshelfcreatebrinerejection;the

NWPisattheendofthecycloniccirculation,sothewaterhasaccumulatedthemost

brine.

(3)Flowinthesubtropicalregionsvacatedbythesubtropicalgyreisveryweak.

Stericheightdifferencesover1000kmdistancesareontheorderof1cmratherthan

the10cmdifferenceswithinthegyreproper.Dynamically,onisopycnalsurfacesthat

arestillwithinthegyreinthewesternregion,thevacatedregioniscalledtheshadow

zone

9.WhatisthesourceofthedeepwaterintheNorthPacific?

Ans:

TwodeepwatersareidentifiedinthePacific:PacificDeepWaterandCircumpolarDe

epWater.PacificDeepWateroriginateswithinthePacificfromupwelledbottomwate

rsandmodifiedUCDW.UCDWoriginatesintheSouthernOceanasamixtureofPD

WandIndianDeepWateranddeepwatersthatareformedlocallyintheSouthernOc

ean.CircumpolarDeepWater(CDW)ispartiallyderived

fromtheDeepWaterofeachoftheoceanbasins:NorthAtlanticDeepWater(NADW)

,PacificDeepWater(PDW),andIndianDeepWater(IDW),andWeddellSeaDeep

WaterisamajorsourceofsuchrenewalofCDW.

10.Whatevidenceisthereforlarge-scaleverticalmixingbetweenthesurface/int

ermediate/deeplayers?

Ans：

Thetemperaturedifferencebetweenthesurfaceanditsurroundingareaisanevidence

forlarge-scaleverticalmixingbetweenthesurface/intermediate/deep

layers,becausethewaterexchangebetweendifferentlayerswillbringcoldwaterup

tothesurface.Besides,thedifferenceinseasurfacelevelisalsoanevidencefor

large-scaleverticalmixing,suchascycloneflow/anti-cycloneflow,whichwillincrease/

decreasethesealevel.

Easternboundarycurrents

11.Whatdirection