海洋学复习资料董志南整理.docx

海洋学复习资料董志南整理.docx

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海洋学复习资料董志南整理

个人观点，仅供参考，如有异议，欢迎讨论，敬请不吝赐教

——董志南

WaterandOceanStructure

1.Whyiswaterapolarmolecule?

Whatpropertiesofwaterderivefromitspolarnature?

BecauseWaterstructureis:

oneoxygenatomisintheabovedirection,twohydrogenatomsbelowareconnectedtotheoxygenatoms.thebondangleofthemisabout105degrees,.Thepositivelychargedcenterofwaterisinthefollowing,whilethenegativeoneisintheabove.Thetwocentersdonotcoincide,Polaritycannotcanceleachotherout.

Cohesion–theabilityofwatermoleculestosticktoeachother,creatingsurfacetension

Adhesion–thetendencyofwatermoleculestosticktoothermaterials,agoodsolvent

DissolvingPropertyofWater

Thesepropertiesederivefromwaterpolarnature.

2.Howisheatdifferentfromtemperature?

Temperatureisameasurementoftheheatcontentofabody.HeatcontentisenergyexpressedinJoulesorCalories.heatisthermalenergytransferredfromoneobjecttoanotherbecauseofatemperaturedifference。

Thetwoquantitiesarerelatedbyafactorcalledthespecificheatcapacitycp:

H=cp*m*T,wherem=massandT=tempinºK

3.Whydoesicefloat?

WhyisthisfactimportanttothermalconditionsonEarth?

Becausethedensityoficeislessthanthatofwater,whenwaterisinliquidform,thecompositionofmoleculeiscloserthanthatofsolidform.Thespacebetweentheicemoleculesismorethanwatermolecules.sotheiceislighterthanthewaterwiththesamequanlity.

因为水在4℃时密度最大，在海中也是处于最低的位置，因此浮冰下的水，其温度皆高于最表层的冰。

无论气候如何变化，海面下温度都保持一定，因此生物得以生长；另外水的潜热（LatentHeat）高,当冰灾水面上时，需要更多的热量来使冰转化成水，这是一个非常重要的原因。

它使得地球气候得以调节，不至于变化过于剧烈。

（中文意思大概如此，自己用英语转化一下就行了）

4.Howisheattransportedfromtropicalregionstopolarregions?

Waterhelpsmoderateglobaltemperaturesbyredistributingequatorialheatpoleward.Warmcurrentfromtropicalregionsgoestopolarregion;atthesametime,coldcurrentformpolarregiongoestotropicalregions.Inthispossession,heatistransformedfromtropicalregionstopolarregions.

5.Whatfactorsaffectthedensityofwater?

Whydoescoldairorwatertendtosink?

Whatroledoessalinityplay?

⑴Temperature

Aswaterfirstcools,densityincreasesandvolumedecreases

Ifthetemperatureisbelow4℃,densityofwaterdecrease.

WaterBecomesLessDenseWhenItFreezes.soat0℃,iceforms,densitydecreaserapidly.

⑵salinity

Soifweaddsomesaltintopurewater,thedensityofwaterincreases

Coldairorwatertendtosinkbecausetheyaremoredenser.

Moresalinity,moredenser;lesssalinity,lessdenser,attheconditionofsametemperature.sosalinityisoneoffactorsdeterminesthedensity.

6.Howistheoceanstratifiedbydensity?

Whatphysicalfactorsareinvolved?

Whatnamesaregiventotheocean’sdensityzone?

Low–densitywaterexistsnearthesurfaceandhigh-densitywateroccursbelow.Exceptforsomeshallowinlandseaswithahighrateofevaporation,thehighest-densitywaterisfoundatthedeepestoceandepths.

Thefactorsinvolved:

temperature,salinity,pressure

Onlytemperatureandsalinityinfluencethedensityofsurfacewater.pressureinfluencesseawaterdensityonlywhenveryhighpressureareencountered,suchasindeepoceantrenches.

0---200m:

surfacelayer;200m---1km:

pycnoclinelayer;1kmbelow:

deeplayer.

7.Howisthepycnoclinerelatedtothethermoclineandhalocline?

Givethedefinitionsofthesethreelayers.

密度越层（pycnocline）是由温跃层（thermocline）和盐跃层（halocline）二者结合形成的。

即使不同的温度和密度，经过适当的结合也能达到密度相等。

Thermocline:

thedepthwherewaterhasasharptemperaturegradient

Halocline（盐跃层）：

thedepthwherethesalinitygradientsaresharp.

密度越层（pycnocline：

Asharpdensitygradientwithdepth.

8.Describethedifferencesbetweentheseasonalthermoclineandpermanentthermocline.

9.Howdoesrefractionpermitsoundtobetransmittedintheoceanforthousandsofmiles?

Soundtransmissionisparticularlyefficient-thatis,soundscanbeheardforgreatdistances-becauserefractiontendstokeepsoundwaveswithinthelayer.

Asthewatercanconcentratesoundwavesinalayer,sothewavecantransmitinonelayer,whichmakesthesoundwavestravelsfaster.Ontheotherhand,thatcanavoidthewavesscatteringtootherlayers,whichavoidsthelossofenergyofsound,sothesoundcantravelfasterandfarther.

10.Whatisthelatentheatofvaporization?

Offusion?

Whichrequiresmoreheattotransferwater’sphysicalstate?

Why?

LatentHeatofVaporizationistheAmountofheatneededtochangefromaliquidtoavapor.

LatentHeatofFusionistheAmountofheatneededtochangefromasolidtoaliquid

Vaporizationrequiresmoreheattotransferwater’sphysicalstatethanfusion.

BecauseAlloftheHbondsbetweenH20moleculesmustbebrokentoformvapor,theHbondsrequiredtobrokenaremorethanfusion,moreenergyisrequiredtoevaporate.

11.Howdoeswater’shighlatentheatinfluencetheocean