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GreenhouseEffectontheCelestialBodiesoftheSolar System
By:AleksandrZhitomirskiyandWalterFiori
Issuedate:27January2025
Introductionn
TheIPCCreportpublishedin1990suggestedthatacomparisonoftemperatureson Earth,Venus,andMarsmayprovideevidencefortheexistenceofagreenhouse effect[1],p.21].Titan,oneofSaturn'smoons,wassuggestedasasecondpossible exampleofagreenhouseeffect[2].However,neithercaseindicateshowtheroleof thegreenhouseeffectcanbedistinguishedfromallthefactorsthatinfluencea planet’stemperature.
Thisarticleaimstopresentthecurrentlyknownfactsanddiscusshowthey correspondtotheideaofagreenhouseeffectinplanetaryatmospheres.
First,itisnecessarytoclarifyhowtheessenceofthegreenhouseeffectis understoodinmodernclimatology,howthetemperaturechangesthatdetermine thiseffectaremeasured,andwhatfactorsinfluencethetemperatureondifferent planets.
ThefollowingfactorswereconsideredintermsoftheGreenhouseEffect:
1. Thecelestialbody’sdistancefromtheSun,itsaxialtilt,thelengthof day/night,anditsproximitytootherlargemasses.
2. Thethermo-physicalparametersofthesurface.
3. Themassofthecelestialbody.
4.
5.
Whetherthecelestialbodygeneratesinternal(geothermal)heat
Thecomposition,pressure,andmassoftheatmosphere.
TheinvestigationconcludedthatthereisnoevidencethattheGreenhouseEffect utilisesatmosphericgasestoelevatethetemperatureofthesurface.
Definitionofthegreenhouseeffect
EncyclopediaBritannica[3]definesthegreenhouseeffectas:
“ a warming of Earth’s surface and troposphere (the lowest layer of the atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air. ”
Letusclarifythatthecompoundslisted,likemanyothergreenhousegases includedintheIPCClist,arecharacterizedbyonecommonproperty:eachofthem doesnottransmitinfraredradiationofcertainwavelengthscharacteristicofeach substance,forexample,4.3μand15μforCO2 ” .
Itmakessensetotalkaboutthegreenhouseeffectonlyforplanetsthathavesuch gasesintheatmosphere,sinceitisthisproperty,accordingtotheconceptofthe greenhouseeffect,whichdeterminestheretentionofenergyintheatmosphereand theincreaseintemperature.
Definitionofaplanet’saverageglobaltemperature
Thegreenhouseeffecttheoryusestheconceptsofaverageglobaltemperatureand theso-calledeffectivetemperature.Thelatterisgenerallydeterminedbya
numericaldetermination,calculationbasedontheamountofenergyemittedbyan objectaccordingtotheStefan-Boltzmannequation.
TherewasamajordifficultymeasuringEarth’saverageglobaltemperatureasnot everybitofitssurfacecouldbemeasured.Hence,itsvaluewassetat15°C,by calculation,afewyearsago.AccordingtotheIPCC,thisvalueis15 oC,excluding Antarctica.
ToindicatethemovementofEarth’saverageglobaltemperature,actual measurementsoftemperatureatmanylocationsaroundtheEartharerecorded, aggregated,andaveragedtocreateanannualtemperatureanomalyvalue.To ensureconsistencyofreporting,thesamemeasurementpointsreporttheirlocal temperaturedataeachyear.
Attheconclusionofarrivingatanewannualanomalyvalue,thevalueisaddedto thecumulativesummationsofbasevalue(15°C)pluspreviousconsecutiveannual anomalyvaluestogiveanindicationofwhattheaverageglobaltemperatureis believedtobeinthelatestyearmeasured.
Thereisnocertaintythatthevaluecalculatedandreportedrepresentsthetrue averageglobaltemperature.However,theaverageglobaltemperaturedetermined isusefulinindicatingwhetherEarthiswarmerorcoolerthanpreviouslyassessed.
Notethattheannualtemperatureanomalyvaluesstandontheirownmerit.Their benefitisthattheycanbeusedtodeterminewhethertheEarthiswarmingor coolingandatwhatrateitiswarmingorcooling.
Giventhatthetemperatureondifferentplanetsvariesoveraverywiderange,and thatinmostcasesthereisnodetailedpictureofthecomponentsoftheir temperatureprofile,thereliabilityoftheaverageglobaltemperaturevalueishighly questionable.
Technologyhascometotherescue,andsatellitemeasurementsareabletoassess thevalueofaplanet’stemperature.Therefore,forapproximatecomparative assessments,actualsatellitemeasurementscanbeused.
Furtherassessmentsoftemperaturefluctuations,suchasorbit-basedmaximumand minimumvalues,dayandnightvariances,aswellasequatorialandpolar variances,areimportantinordertocompleteacelestialbody’stemperatureprofile.
Ofparticularinterestarejumpsintemperaturefoundindifferentplacesatdifferent times.
Factorsaffectingtemperature
Ingeneral,thesefactorsarerelatedtotheamountofthermalenergyenteringthe planet,thedistributionofthisenergyontheplanet'ssurface,andthenatureofthe substancethatabsorbsandreleasesheat.
TheSolarconstant(G).
Thevalue,G,resultsindeterminingthevalueofthesun’sthermalenergyfalling onacelestialbody,suchasEarth,inaccordancewiththeequation:
Where:
● L isthesolarradianceinWattspermetressquared(W/m²)emitted fromthesurfaceofthesun,
● R istheradiusoftheSuninmetres(m),and
● d isthedistancefromthesuntothecelestialbodyinmetres(m).
ThevaluesofLandRareconsideredtobeapproximatelyconstant,butthevalue ofdchangeswithtimeasthecelestialbodybeingassessedmovesfromperihelion toaphelioninitsorbit.Sincethesolarenergyfallingonthecelestialbodymayor maynotbedistributedevenly,andthethermo-physicalpropertiesofthesurface materialmaydifferindifferentplaces,therelationshipbetweenthesolarconstant andthesurfacetemperatureiscomplex.
AllcelestialbodiesintheSolarSystemhavedifferentdynamicsintheirrotational, orbital,andaxialinclinationproperties.Itisnotasimplemattertodeterminethe resultingtemperatureofacelestialbodybycalculationalone.Thereare
difficulties,therefore,inbeingabletocompareassessedtemperaturesbetweenone celestialbodyandanother.
Otherfactors
Thereisalsotheuncertaintyofacelestialbody’sothersourcesofsurface temperatureaffectingheat,andwhetherthecelestialbodyhas,ordoesn’thave,an atmosphereandwateronitssurface.
Therearealsootherfactorsthatcanhaveaneffectonacelestialbody’ssurface temperatureprofile,suchas:
● Geothermalheat-knowntoaffectEarth’ssurfacetemperature.
● Geothermalheatcouldhaveaneffectonthesurfacetemperatureofotherof the SolarSystem’scelestialbodies.
● Earthalonehasananthropogenicfactorthataffectsitssurfacetemperature.
● Orbitalvelocityandgravitationalforcesactinginoppositioncanalsobea sourceofinternalheatgenerationthataffectsthesurfaceofacelestialbody. Thisisofparticularinterestwhenrelatedtocelestialbodiesthatorbita parentplanet.It’stheforcesgeneratedbytheorbitalvelocityand gravitationalinteractionsthatkeeptheorbitingbodyfromcrashingintothe planet Titan,abodythatorbitsSaturn(oneofSaturn’smoons),issucha celestialbody.
Theobliquitytoorbitofplanets.
Obliquity,alsoknownasaxialtilttoorbit,referstotheanglebetweenthe rotationalaxisofaplanetandtheperpendiculartoitsorbitalplane Atiltvalueof zerocorrespondstothecelestialbodynothavingtheseasonaleffectasexperienced onEarth,wherethenorthernandsouthernhemispheresalternatetheir summer/winterexperiencesataphelionandperihelion.
Instead,thedistanceacelestialbodywithazeroaxialtiltisfromthesunduringits orbittimedeterminesseasonalvariationsaffectingthewholeofthesurface.Its
orbitswingsthewholeofthecelestialbodyinafluidmotionfromsummer(hot withhighestinsolationatperihelion)towinter(coldwithlowestinsolationat aphelion).Thespringandautumnseasonsarenotseparatorsofoscillating hemisphericsummersandwintersasoccursonEarth.Thecelestialbodywithan axialtiltofzeroispermanentlyinastateofequalhemisphericalirradiation.
Earth’sobliquitytodayis23.5°.DespitethisbeingEarth’scase,thesunwouldn’t seetheEarthasanythingotherthanasingularmasswithafacingsurfacethat receivestheheatdirectedtoit.Thesun’sirradiationisoblivioustothefactthatthe Earthhasanangleofobliquity.
Hencetheaverageglobaltemperature,anoverallassessmentofacelestialbody’s temperatureoveroneorbitofthesun(notnecessarilyoneearthyear),is independentofobliquityandsubjecttothedifferencebetweenincomingand outgoingradiationbasedonboththecelestialbody’sdistancefromthesun,the intensityofthesun’sirradiationandanyotherincidentalsourcesofheatthataffect thesurface.
Earth’sobliquityservesanotherpurpose.ItoscillatesthepartofEarth’ssurface thatreceivesthesun’sinsolation,transferringtheheatreceivedtolocationsthat wouldotherwisereceivelimitedtononeoftheSun’sirradiation.
OnEarth,theobliquitydistributesthetotalenergyreceivedabouttoday’s hemisphericallatitudesasitswings47°oflatitudeinoneorbitoftheSun,thereby enhancingtheconditionsoflivabilitythroughouttheEarth.Thus,itchangesthe resultingsurfacetemperaturegradientsbynotconcentratingitsheattoastatic latitudeaswouldoccuriftheobliquitywere0°.
Iftheearthhad0°obliquitythen,basedon…
● Thesolarconstantof1367W/m².
● Theatmospherehasthesamemassandcomposition.
● Irradiation’sminimumlossof52%asittraversestheatmospheretothe surface.
● Aunitofinsolation’sgreaterareaofcover(surfacerelief)thefurtherupthe latitudesitreaches.
● Anequivalent328W/m²(24%ofthesolarconstant)atthetopofthe atmosphere,representingavalueof82W/m²astheaverageofthesurface insolationdistributionacrossthewholeofthesurfaceareadefinedby latitudes0°to90°,where0°istheplaneoftheecliptic.
…theearthwouldbesubjectedtothefollowingconditions:
1.
Latitudes+10°to-10°abouttheequatoronthelongitude perpendiculartotheeclipticwouldreceiveaconstantaverage650W/m².The areawouldbeperpetuallyhot.
2.
Latitudes80°to90°,inboththenorthernandsouthernhemispheres,would beperpetuallycold Theselatitudeswouldreceiveaconstantaverageof 58W/m²onthelongitudeperpendiculartotheeclipticduetothe significantlygreaterlossoftheirradiationasittravelledtothesurface throughtheatmosphere,anditspreadacrossagreaterarea.
3.
Ifboththetotalsurfaceareathelatitudeseparatorsrepresentandthe day/nighteffectsaretakenintoaccount,theequatorialregionswouldreceive aconstant163W/m²andthePolarRegionswouldreceiveaconstant14W/m² i.e.,8.6%oftheW/m²receivedattheequatorialregion.
Insummary:
1.
Theaverageglobaltemperaturewouldbethesamevaluewhetherthe obliquitywas0°or23.5°inabodythathadnoothersourceofincidental heatandnoheatstoragematter.Inthiscase,thecelestialbodyissubject onlytotheintensityoftheSun’sirradiationandthedissipationofthe interceptedheattospace.
2.
Thepositionandsurfaceareaofbothoceansandland,themassofthe atmosphere,water,andincidentalheatsourcesthatimpactthecelestialbody, includingthesunastheprimaryheatsource,wouldallhaveabearingon heatcapture,dissipation,andresultantaverageglobaltemperature.
3.
Thetiltofaplanet'saxisaffectsthedistributionofincidentsolarradiation. Differencesinaxialtiltvaluesofdifferentcelestialbodiesintroduce uncertaintyinassessingthecausesofsurfacetemperaturedifferencesat specificpointsofcelestialbodiesbeingcompared.
4.
Othersourcesofincidentalheatcancontributetothesurfacetemperatureof acelestialbody.
Siderealrotationalperiod.
Thisvalue,whichdeterminesthetimeittakesforacelestialbodytorotateabout itsaxis,affectstheamountofheatthecelestialbodyreceiveswhenitfacestheSun andtheamountofheatthecelestialbodydissipateswhenitnolongerfacesthe Sun.Notethatamoonthatorbitsaplanet,suchasTitan,willalsohavean additionalimpedimenttoitsabsorptionofthesun’sheatwhenitmovesintothe shadowoftheplanetitorbits.
Thematterthatabsorbstheirradiationconsistsoftheland,atmosphere,andwater ifthelattertwomassesexistonthecelestialbody.Othersourcesofheatdirectedto thesurfaceaddtothetotaloftheheatabsorbedfromthesun’sinsolationwhilethe surfacefacesthesun.Dissipationofthesurfaceheatbeginswhentheincoming heatbecomeslessthanthetemperaturethecelestialbody’ssurfacehasbeen elevatedto,andincreasesinitsrateofdissipationwhenthesurfacenolongerfaces thesun.
Thematterthatstoresheatdeterminestheextentofheatdissipationbasedonits propertiesandmass.Ifthecelestialbodyisonawarmingtrend,lessheatis dissipatedthanabsorbed.Theoppositeoccursifthecelestialbodyisonacooling trend.
Comparisonsbetweencelestialbodiesthatdon’thaveanatmosphereora substantialamountofwatertothosethathavearesubjecttoerrorininterpretation.
Thesepropertiesincludetheabilitytoreflectsolarradiation(albedo),thermal conductivity,andheatcapacityofthesubstancesthatformthesurface,andsurface relief.
Thepropertyofthealbedo,itsreflectivity,issetataparticularvalueiffactorsthat impactthevalueofthealbedo,suchastheclimateofaparticularlocation,remain thesameoveranextendedperiodoftime.Ifanyofthefactorspertinenttothe determinantvalueofthealbedochange,thenthevalueofthealbedochanges.The changeinalbedohappensafterthefactorsthatdeterminethevalueofthealbedo change.Thechangeinthevalueofthealbedoisaneffectandnotacause.A changeinthepropertyofthesurface,andhencethevalueofthealbedo,could resultineitheranincreaseoradecreaseinthereflectivityofthesurface.
Thermalconductivityandheatcapacityofsubstancesarepropertiesparticulartoa matter.Theyplayanimportantpartinthecaptureandreleaseofincoming radiation.
Surfacerelief,asitappliestotheangleofincidenceoflightfallingonthesurface ofaplanet,isthebasisofdeterminingthechangeintheintensityofincomingsolar radiationbasedonitssquaremetrevaluethefurtherupthelatitudestheincident lightreaches.
Presenceandcompositionoftheatmosphere.
Thefactthattheatmospheredelaysthereleaseoftheplanet'sabsorbedheatinto spaceisobvious.Thequestioniswhetherthisisduetotheabilityofcertaingases toabsorbinfraredradiationortotheheatcapacityofallthecomponentsofthe atmosphere.
Thereareconflictingargumentsaboutthisaspectofsurfaceheatdissipationto space.
Researchconductedasreportedinthearticle
https://www.academia.edu/83219570/Earths Energy Balance and Thermodynami c Propertiesindicatesthatthewholeoftheatmosphereparticipatesinthe dissipationofEarth’sheattospace.Theatmosphereactsasaconstantlyactiveheat
transfermechanismfromthesurfacetospaceinaccordancetoincomingand outgoingheatsupplyandthermodynamicdifferences.
AnalternativeconceptembracedbytheGreenhouseEffectisthattheadditionof carbondioxidetotheatmosphereincreasestheeffectofacreatedradiativeforce thatwarmstheEarth’ssurface.Theobjectiveofthisarticleistodiscusswhether carbondioxidehasthecapacitytocauseEarth’sglobalwarmingdilemma.
Specificfactors.
Theseincludetheplanet'sinternalheat,unpredictablemovementsofatmospheric andwater(inthecaseofEarth)currents,andpossiblyprocessesthatarecurrently undetected.
Boththeatmosphere’sgasesandwaterhavethecapacitytoabsorbandstoreheat. Waterismuchbetteratstoringheatthantheatmosphere.(1kgofwaterabsorbs4.2 timesmoreheatthan1kgoftheearth'satmosphere). Waterisalsoaperpetual supplierofheattotheatmospherebywayofthehydrologiccycle;bothin observanceofthelawsofthermodynamicsandthebehaviourofthehydrologic cycle.
ComparisonofMercuryandVenus
MercuryisclosertotheSunthanVenus,andaccordingly,theaveragevalueofthe solarconstantforitismuchgreater:9116versus2611W/m2, respectively.Atthe sametime,Mercuryisassignedanaveragetemperatureof440K,andVenus737K [4].Thisfactisusuallyexplainedbythegreenhouseeffectoftheatmosphereof Venus,whichconsistsof96.5%carbondioxide.However,thepossibleroleof otherfactorsmustalsobeconsidered.
VenushasanatmospherecomposedprimarilyofCO2gas,whichcanholdand transmitheattospace.Mercurydoesnothaveanatmosphere.Therotational propertiesofeachoftheplanetstherefore,haveadifferentimpactonitsheat contentanditsaverageglobaltemperature.
OnVenus,duetothelongdaylighthours(thelongestamongtheplanetsinthe solarsystem),thetemperaturedifferenceisrelativelysmall:theaverage temperatureonthenightsideisfoundtobe698K[5].AttheMercurydayside reachestemperatureof700K,whilenightsidecoolsto93K[6].
However,beforeproceedingwiththisnotionoftheplanets'day/nighttemperatures andconsequentaverageglobaltemperature,it’simportanttoevaluatethereasons eachplanethasthemeasuredtemperaturesbasedoneachplanet’sknownorbital androtationalproperties.
TheabovedatacorrectlyrepresentsthetemperaturevaluesofbothMercuryand Venus.However,it’simportanttonotethatthemeasurementsdonottakeinto considerationtwo(2)importantfactorsthatdetermineMercury’stemperatureon thedayandnightsides.Thesefactorsare:
1. Mercury’sproximitytothesun
2.
Mercury’sslowrateofrotationcausesittobeellipticallytidallylockedto thesun[20]ina3:2resonance.Mercuryrotatesonitsaxis1.5 timesduring 1orbitofthesun.
Figure1showsMercury’srotationasitorbitsthesun(fromabove),andthatit completes2orbitsbeforethesamesurfacefacesthesunagain.Hence,theterm “ellipticallytidallylocked”isappliedtoMercuryandtheSun’srelationship.
Thesun’sirradiationispersistentonthesurfacefacingthesunfor587Earthdays ofMercury’s88Earthdays’orbitofthesun
Figure2showsdifferentphasesofthesun’sirradiationstrikingMercury’s changingsurfaceareaasitrotatesonitsaxisduringitsorbitofthesun
Theconsequenceofthetwo(2)factorsnotedaboveisthatMercuryabsorbsagreat dealofheatthatisstoredinthewholeofthemassofMercury.Theheatisslowly releasedonthenightsideoftheplanet,whereitssurfacenighttemperaturehas beenmeasuredat93KdespiteMercury’sexposuretothecoldofspaceandnot havinganatmosphere.
Therefore,theestimateofMercury'saveragetemperatureisunderstandableasits proximitytothesun,itsorbitalandrotationalproperties,andtheabsenceofan
atmospherecreateanorbitingplanetaryentitythatcannotberelatedtothe dynamicsandpropertiesexhibitedbyVenusorEarth.
However,theroleoftheatmospheremakessensetodiscusswhencomparing VenuswithEarth.
VenusandEarth
WhencomparingtemperaturesonVenusandEarth,itisnecessarytotakeinto accountsuchcomparisonfactorsasthevaluesof: ComparisonData
Venus’s177.4°obliquitytranslatestoithavinganoscillationabouttheeclipticof 2.6°.Hence,Venus’sobliquityisnotparticularlysignificant.Itwouldnotallowfor anymajorredistributionofthesun’sheatdirectedtoVenusabouttheoscillating latitudes
DuetothemanytimeslongerdaylighthourscomparedtoEarthandthesmall orbitalinclination(thepracticalabsenceofseasonaltemperaturechanges),Venus, intheabsenceofanyothersignificantformofheatimpactingthesurface,isheated toahighertemperatureprincipallyduetoitsproximitytothesun.Onlythesun, therefore,determineshowhotVenusbecomes.Thisisdespitethepossibilitythat
Venusalsogeneratesgeothermalheatthatcontributestothetotaltemperaturethe planethasbeenmeasuredtohave.
ThatVenusreachesahighertemperaturebecauseofitsproximitytothesunandits longerdayisunderstandable.Butitsnighttimewouldalsolastlonger,and thereforeithasmoretimetodissipateitsheattothecoldofspace.Venus’saverage globaltemperaturewouldsettletoavaluethattakesintoconsiderationthesun’s incomingirradiation,anygeneratedgeothermalheat,itscapacitytostoreheat,and itsrateofdissipation
Venus’sfasterrateofrotationandatmospherewouldpresentitselfwithadifferent temperatureprofile,notassteeplyinfluencedbyitsproximitytothesunas Mercury,butstillsubjecttoitscapacitytostore,permeateandmaintaininternal heatduetoitsrobustatmosphericcapthatwouldmaintainaconstanttemperature aboutitswholesurface.
It’sVenus’srateofdissipationoftheheatitabsorbsthatisthequandary.The questionofwhatretainstheheatatthesurfacelingers.
Thematterisfurtherinflatedbythefactthatat-14°latitudeandsolarzenithangle 17°[17]onlyabout3.4%oftheincidentsolarenergyreachesthesurface (2622W/m²atTOAand89.4W/m²onthesurface).Hence,astheday/nightsurface temperaturesareequal[18],thenitcanonlybetheheatcontainedintheadditional solarradiationthatreachesthesurfacethatisdissipatedonthenightsideas quicklyasthedaysidereceivesitinamannerthatmaintainsequalsurface day/nighttemperaturevalues.
ThereisnowateronVenus.Anycalculationappliedtodetermineitssurface temperaturewould,orshould,showthatitstemperatureisbasedontheheatthe landandatmosphereabsorbsfromthesunanditspossiblegeothermal complement.
Additionally,thepossibilityofatmosphericheatdistributionintheVenusian atmospherealsoneedstobeconsidered.Heatcouldbetransferredfromhottocold regionsofVenusbythesurfacewindsthatrangeinspeedof0.3to1.0m/s[19] therebyequalisingthesurfacetemperaturebetweenthedayandnightsurfaces.
OnEarth,morethantwo-thirdsofthesurfaceisoccupiedbywater,theheat capacityofwhichismuchhigherthanthatofthesubstancesthatformthesurface oftheland.Accordingly,thesurfaceofthewaterisheatedtoalowertemperature. ThereisnowateronthesurfaceofVenus.Itssurfacetemperaturewouldcauseall thewatertoboilaway.Furthermore,thereisnodataontheheatcapacityofthe Venusianground.Itcanbeassumedthatthisvalueislowerthanforwater,and, therefore,allotherthingsbeingequal,thesurfaceofVenuscanheatuptoahigher temperaturethanthesurfaceofwateronEarth
Onecouldeasilyassumethepresenceofintensevolcanicactivityand, consequently,amuchgreatercontributionoftheplanet'sinternalheatcomparedto Earth,basedonthefactthattheatmosphereofVenusconsistsmainlyofCO2
However,thatassumptionmaybeincorrect.Itcouldbethat,atthetimeofVenus’s formation,allthecarbonavailablewascombusted.Itscurrentatmospheremaybe theresidualoftheoriginalcombustionthatcreatedtheCO2 andothervaporised molecularcompounds,suchasthecloudsofsulphuricacid[21],thatgravityheld ontoastheplanet’ssolidmatterformedandconsolidatedintotheplanetit ultimatelybecame,completewithanatmosphere.
Analternativepossibilitytoitssurfaceinstabilityisthatthecontinualintense radiationfromthesuncreatedaninternalheatthatcausedVenus’smantle becomingvolatile:conditionswhich,togetherwithacombinationofgravitational influences,createdsurfacevolcanicandseismicconvulsions.
Takingintoaccounttheabovecircumstances,itisextremelydifficult(ifpossibleat all)toisolatetheroleoftheatmosphereinheatingtheplanet.Althoughthe atmosphereactingasalidonVenusisquitepossible.
Venus’sandEarth’satmospheresdiffersignificantlyinboththetotalamountofgas andincomposition.TheatmosphericpressureonVenusis93timeshigherthanon Earth.
TheatmosphereofVenuscontains965%CO2 (a“greenhouse”gas)and35%N2 (a“non-greenhouse”gas).TheatmosphereofEarthconsistsmainlyofthe “non-greenhouse”gasesO2,N2,andArandcontainsvariableamountsofthe “greenhouse”gasH2O(fromhundredthsofapercentto4%)andabout0.04%CO2 (calculatedonadryairbasis).Thequestionofwhethertheeffectoftheatmosphere
isdeterminedbythetotalamountofgasorbythe“greenhouse”gasesisof fundamentalimportance.
TheessenceofthegreenhouseeffecthypothesisproposedbyArrhenius(1896)to explaintheheatingoftheatmosphereandthesurfaceoftheEarthisthat greenhousegases(CO2 andH2O)absorbinfraredradiationreflectedfromtheEarth andretaintheabsorbedenergyintheatmosphere,slowingitsreleasetospace.
SolarradiationfallingontheEarthcoversarangeofenergiesfromhigh(cosmic rays)torelativelylow(nearinfraredregion),whichcorrespondstowavelengths fromthousandthsofamicrometre(μ)to4μ.Themainabsorptionbandsofcarbon dioxide(near4.3μand15μ)areintheregionofinfraredradiationreflectedand emittedbytheEarth,whiletheroleofband4.3μisnotmentionedinpublications onthegreenhouseeffect.
Itislogicaltoassume(thereisnodatacontradictingthisassumption)thatthe distributionofsolarenergybywavelengthonVenusisthesameasonEarth.The resultsofthestudiesintheabove-citedworkofR.Singh[5]inagreementwith otherauthors,showthatonlyabout2.5%ofsolarenergyreachesthesurfaceof Venus(forEarth,thisvalueisabout50%).Howcanthisenergybeconvertedinto theenergyofinfraredradiationabsorbedbycarbondioxide?Forsuchabsorption, itisnecessarythatthewavelengthoftheradiationatleastapproachthemain absorptionbandofCO2.
BasedonWien'slaw,whichrelatesthewavelengthcorrespondingmaximum intensityofradiationandthetemperatureoftheemittingsurfaceintheequation: λmax=b/T
(Where:b=2898μ/KandTisthetemperatureofthecelestialbody)
Itwasfoundthatthecalculatedλmaxvaluesfor“mean”temperaturesof288K (earth)and737K(Venus)[4]resultinwavelengthvaluesof10.1μand3.9μ, respectively.Thatis,Venus’scalculatedvalueisconsiderablyfurtherawayfrom CO2’sstated15μabsorptionbandthanthevaluecalculatedforEarth.
Itisimportanttonotethat,although“mean”temperatureswereusedintheabove calculation,itistheactualphysicaltemperaturesthatdeterminethewavelengthof theradiationwhencalculatedbyWien’sLaw.InEarth’scase,thewholeofits
surfaceisatdifferenttemperaturesandwouldthereforebeemittingradiationsof differentwavelengthsbasedontheactualphysicaltemperatureoftheradiating surface.Eachpocketofcommontemperaturewouldhavetobecalculated independentlyforitsemittedradiation’swavelength.
IfwetakeintoconsiderationthatEarth’sday/nighttemperaturerangesaboutthe baseof288Kfrom260Kto308Kataparticularlatitudeandlongitude,thenthe maximumoftheemittedradiationfromtheplanetwouldbeintherangeof11.15μ to9.41μ.ThisrangeofwavelengthsdoesnotcorrespondtoCO2'spredominant15μ absorptionbandsnortoits4.3μ,2.7μ,and2.8μabsorptionbands.
Thisdoesnotatallagreewiththeideaoftherolecarbondioxideisexpectedto playinheatingthesurfaceandatmosphereofVenusbasedontheconceptofthe greenhouseeffect.
EarthandMoon
Comparisonofthesetwocelestialbodiesisofinterestbecausetheybothreceive approximatelythesameenergyperunitsurfaceareafromtheSun,whichmakesit possibletojudgetheroleofotherfactorsinfluencingtemperature.Becauseofthe lackofanatmosphere,theMooncanonlygiveofftheheatitreceivesfromtheSun byradiation.
TheStefan-Boltzmannequationisthereforeapplicabletothisprocessifthe amountofenergyabsorbed,aswellasthevaluesofalbedoandemissivityofthe substance(s)thatmakeupthesurface,canbereliablydetermined.Itshouldbe notedthat,inaccordancewiththeideaofthegreenhouseeffect,NASAexperts attributeanaveragetemperatureof-20°CtotheMoon[4],whichroughly coincideswiththe"effective"temperatureoftheEarth-18°C.SincetheBond albedovaluefortheMoonissmallerthanfortheEarth(0.11versus0.294),the calculatedvalueofthe"effective"(blackbody)temperatureturnsouttobegreater thantheaveragetemperature:270.4K(-2.8°C)[7].
Despiteitbeingpossibletojudgetheroleofotherfactorsinfluencingthe temperatureoftheMoonandEarth,therearesignificantdifferencesthathavetobe takenintoconsiderationwhenconsideringtheMoon,otherthanthelackofan atmosphere.
TheMoonhasnowateronitssurface.Thereisalsonoinformationonwhetherthe Moongeneratesanyinternal(geothermal)heat.Avalidcomparisonbetweenthe2 bodiescanonlybebasedonlandmatter.
Also,theMoonhasparticulardynamicsthatdifferfromEarth:
1. ItsdaysurfacetemperaturevariesonlywiththedistancetheEarthisfrom thesunduringEarth’sorbitaroundthesun.
2
Itsrotationaboutitsaxisisconstant.
3. ItisacelestialbodytiedtotheEarthwithpartofitsorbitoftheEarth, causingittobeinEarth’sshadowofthesun.
4. ThegravitationalforcesthatapplybetweentheEarthandtheMoonare nearlyconstant(theMoonisslowlydistancingitselffromtheEarth).
Inconclusion,withoutwateroratmosphere,themoonrepresentsabodythatcan’t becomparedtoEarth.ItmaybepossibletoapplytheStefan-Boltzmannequation tobothbodiestoderivecomparativevalues,buttheresultswouldneedtohave several“modifications”toarriveataparticularlybindingrelativitythatcanbeused tosupportordenytheCO2 theoryofglobalwarming.
Nonetheless,duetothestrikingenvironmentaldifferencesbetweentheMoonand theEarth,thetemperaturesarrivedatbytheNASAexpertscannot beexplainedby thegreenhouseeffecttheory.
DespitethestarkenvironmentaldifferencesbetweentheMoonandEarththeIPCC considersthepositivedifferencebetweenthemeanandeffectivetemperaturesof theplanetasoneoftheproofsofthegreenhouseeffectandattributesthisentire differencetogreenhousegases[1].
Ifthisisso,thenontheMoon,wherethereisnoatmosphereatall,these temperaturesshouldcoincidewithinthecalculationerror.Thefactthatthemean temperatureontheMoonislowerthantheeffectivetemperatureindicateseither thatoneofthesequantities(orboth)isincorrectlydetermined,or,morelikely,that theveryideaofcomparingthesequantitiesisincorrect
Amatterthatneedsfurtherconsideration,inadditiontotheabsenceofan atmosphere,isthattheMoonhasnowateronitssurface.Theimportanceofthe absenceofwatercannotbeignored,orwashedaway,inanycalculationtoassess theMoon’smeanoreffectivetemperatures.
Sincetheheatcapacityandthermalconductivityofwateraremuchgreaterthan thoseofthesubstancesthatformthesurfaceoftheland(sand,soil,clay,etc.),then withanequalamountofabsorbedthermalenergythisleadstotheemergenceofa significantdifferenceintemperaturebetweendifferentareasofthesurface.A studyofthethermo-physicalpropertiesofthelunarsoil(regolith)showsthatthey varygreatlywithtemperature[8],butthereisnoevidenceofsignificant differencesindifferentpartsofthesurface.
Basedonthis,onemightexpectatemperaturedifferencebetweenthepolarand equatorialregionsontheMoon,witharelativelystabletemperaturewithinthese regions.However,thisassumptionisnotsupportedbytheresultsofmeasurements [9].Theseresultsprovidedetailedinformationontemperaturechangesindifferent areasofthelunarsurface,maximumandminimumtemperaturevalues,the presenceofrelativelywarmerandcolderareas,andtemperaturevariationsat differentlatitudesandatdifferenttimesofthelunarday.Inparticular,the maximumtemperatureatmiddayattheequatorreaches397K,andatnightinthe PolarRegions(latitude85degrees)itdropsto50K.About250billion measurementsweremadebetweenJuly2009andApril2015,buttheauthors[9] donotraisethequestionofestimatingtheaverageglobaltemperatureoftheMoon: thefactsshowthatthisvalueismeaningless.
EarthandMars
Asinpreviouscases,thefactsthatmayberelatedtothegreenhouseeffectare considered.Thefollowingastronomicalparametersareknown[10]:
Astronomical Parameter
6 km
6 km
Fromthecomparisonofsolarradiationvalues,itisobviousthatthetemperatureon MarsissignificantlylowerthanonEarth.SinceMarshasagreaterdifference betweenthedistancestotheSunatperihelionandaphelion,andalsoasomewhat largervalueofobliquity,onecanexpectgreatertemperaturedifferencesthere comparedtoEarth.Indeed,temperaturecanvaryfrom-125°Cnearthepolesto 20°Catmiddayneartheequator[11]duringthewinter.
TheaveragetemperaturevaluesforMarsreportedindifferentsourcesarenotthe same:
● -65 °C(208K)inreference[4],
● -60 oC(213K)inreference[11],and
● -55 °C(218K)inreference[12].
TheIPCCacceptsthevalueoftheEarth’saveragetemperaturetobeabout15 oC (288K).
Incontrast,thecalculatedvaluesofblackbodytemperaturewerefoundtobe209.8 KforMarsand254KforEarth[10].
SinceMars,unlikeEarth,doesnotshowareliabledifferencebetweenthemean andeffectivetemperatureattributedtothegreenhouseeffect,letuscomparethe atmosphericcharacteristicsofbothplanets.
ThetotalatmosphericpressureonMarsis6.35mbar[11]comparedto1baron Earth.ThevolumeconcentrationofcarbondioxideintheatmosphereofMarsis 95.3%[11]comparedto0.042%onEarth.Itfollowsthatthepartialpressureof CO2 onMarsis14.4timeshigherthanonEarth.Thus,onMars,withamuch higherpartialpressureofgreenhousecarbondioxide,nosignificantdifferenceis foundbetweentheaverageglobalandeffectivetemperatures.Thesefactsareinno wayconsistentwiththeideaofthegreenhouseeffectandappeartobeignoredby thesupportersoftheCO2-basedgreenhouseeffect.
Titan
Whentalkingaboutthegreenhouseeffect,itisnecessarytofirstdeterminethe amountofenergyfallingontheplanetandthegreenhousegasthatholdsthis energyintheatmosphere.Titan,asasatelliteofSaturn,receivesapproximatelythe sameamountofsolarenergy(15W/m 2)i.e.approximately90timeslessthan Earth.TheatmosphericpressureonTitanis1.6timesgreaterthanonEarth,the atmospherecontainsabout95%nitrogenandabout5%methane,andtheaverage temperatureistakentobe-179 oC(94K)[13].Thegreenhouseeffecthypothesis attributesgreenhousepropertiestomethane,whichabsorbsinfraredradiationinthe wavelengthrangesof3.1-3.6μand7.4–8.2μ.Thevalueofλ maxaccordingtothe Wienequationforatemperatureof94Kis30.8μ,thatis,veryfarfromthe absorptionbandsof"greenhouse"methane.
TheauthorsofthepublicationonthegreenhouseeffectonTitan[2]claimthat"a greenhouseeffectcausedprimarilybypressure-inducedopacityofN2,CH4,and H2 ”.Thisisaratherstrangestatement,contrarytothegenerallyaccepteddefinition ofgreenhousegases.Indeed,nitrogenandhydrogenmoleculesarenon-polar,have nodipolemoment,andnovibrationalmodesresponsibleforabsorptioninthe infraredregion.ThetemperatureonTitanisclosetothecondensationtemperature
ofnitrogen(78K).However,evenliquidnitrogenat66Kexhibitsabsorptionof radiationintheregionof30-150cm-1 (330-67μ)withamaximumat55cm-1 (180 μ)[14],thatis,veryfarfromtheabove-mentionedvalueλ max forTitanat94K.
Similarstudiesofinfraredabsorptionhavenotbeenfoundforhydrogen.Giventhe lackofdataonthetemperaturedistributiononTitan'ssurface,the"average" temperatureof94Kcannotbeconsideredreliableeither.Therefore,theassertion aboutthepresenceofagreenhouseeffectonTitancannotbeconsideredjustified.
Jupiter
Jupiterisnotmentionedinanypublicationonthegreenhouseeffect,althoughthis giantgasplanet,consistingofnon-greenhousehydrogenandhelium,hasthe highesttemperatureinthesolarsystem.Thetemperatureinthecenteroftheplanet reaches25,000Katapressureofabout50-100millionatmospheresand decreasesfromthecentertothesurface:forexample,atapressureof22atmitis 400K[15].Itisquitepossiblethatatapressureofabout90atm,thetemperature onJupiterwillbeofthesameorderasonVenus.Itisdifficulttofindamore illustrativeexampledemonstratingtheconnectionbetweentemperatureandgas pressure,especiallyforgasesthatdonotabsorbinfraredradiation,i.e.,thosethat areclearlynotrelatedtothegreenhouseeffect.
R.I.Holmes[16]calculatedthetemperatureforJupiteratanatmosphericpressure equaltoEarth'susingamathematicallymodifiedformoftheidealgasequation:
T=PM/Rρ
(Where:Misthemeanmolarmassandρisthedensityoftheatmosphere.)
ThevalueofMiscalculatedbasedonthecompositionoftheatmosphere,andthe densitycanbedeterminedusingreferencedataonthedensityofgasesatvarious temperaturesandpressuresandusingtheadditivityruletocalculatethedensityof thegasmixture.Thus,thecoincidenceofthecalculatedandmeasuredtemperature valuesusingtheHolmesmethodessentiallyshowstheapplicabilityoftheidealgas equationinacertainrangeoftemperaturesandpressurestoatmospheresof differentcompositions.Thefactthatthiscalculation[16]turnedouttobe applicablebothtotheatmosphereofJupiter,consistingofnon-greenhouse hydrogenandhelium,andtotheatmosphereofVenus,madeofgreenhousecarbon dioxidecanbeconsideredaseriousargumentagainstthegreenhouseeffecttheory.
Conclusion
Evidenceofthegreenhouseeffectinaplanet'satmospheremaybeachangeinthe temperatureoftheatmosphereand/orsurfacethatcanbereliablyattributedto greenhousegas,takingintoaccountallotherfactorsaffectingtemperature.The methodofcomparingglobalaverageandeffective(blackbody)temperatures adoptedinmostmodernstudiescannotbeconsideredcorrectduetothelackof dataonthedistributionoftemperaturesontheplanetsandtheamountofenergy emittedbytheplanets.Atthesametime,thelackofdifferencebetweenthese temperaturesmayserveasanargumentagainstthegreenhouseeffect.
WhencomparingthetemperaturesofVenusandMercury,thehighertemperature onVenusisusuallyattributedtothegreenhouseeffectofCO2 intheatmosphereof Venus.However,itisnotpossibletoquantifytheinfluenceontemperatureofsuch astronomicalfactorsasthemuchlongersolardayonVenus,thegreaterdifference betweenthedistancesfromtheSunatperihelionandaphelionforMercury,andthe muchsmallermassofMercury.
ForVenus,ithasbeenestablishedthattheamountofsolarenergyreachingthe surfaceisonly2.5%ofthetotalamount;therefore,almostalltheenergyis absorbedbytheatmosphere.Thedistributionofsolarenergybywavelength, accordingtodatafortheEarth,correspondstotherangefromultrashortto4μ. SincethemainabsorptionbandsofCO2areat4.3μand15μ,itturnsoutthateither carbondioxidecouldnotabsorbtheincidentsolarenergy,ortheabsorptionofheat bytheatmosphereisnotassociatedwiththeabilityofthegastoabsorbinfrared radiation.Thelatterismorelikely.
WhencomparingtheatmospheresofEarthandMars,itisclearthatthetotal atmosphericpressureonEarthis160timesgreater,butthepartialpressureof greenhousecarbondioxideis15timesgreateronMars.Atthesametime,the differencebetweentheaverageglobalandeffectivetemperaturesonMarsiswithin thecalculationerror,which,accordingtotheory,doesnotindicatethepresenceofa greenhouseeffect.Thisobviouscontradictionisnotexplainedinanyworkonthe greenhouseeffectinplanetaryatmospheres.
AnattempttoprovethepresenceofagreenhouseeffectinTitan'satmospherealso cannotbeconsideredconvincing,sincetheauthorscouldnotexplainwhatthe sourceoftheenergyis(theenergyofsolarradiationonTitanisapproximately90
timeslessthanonEarth)anddidnotprovehownitrogenandhydrogencould acquirethepropertiesofgreenhousegasesundertheseconditions.
Asaresult,itcanbeconcludedthattheexistenceofthegreenhouseeffectinthe atmosphereofplanetshasnotbeenproven.
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