Klimaforskning - hjemmeside
Startet av Okular, desember 27, 2012, 22:05:12 PM
SitatKristianSoD, you say (referring to your Figure 4):"Let's consider the surface. On timestep 1 the surface is radiating 376 W/m² (note 1)."I find this a somewhat misleading statement. Or at least a bit halfway. Since the Earth's surface is not a BB in a vacuum, the real (net energy/heat transferring) IR flux from the surface (to the atmosphere) in your model would be 376-284=92 W/m^2, not 376 W/m^2. In Figure 4 one might be confused into thinking that you liken the IR 284 W/m^2 coming down from the atmosphere, mainly heated by the surface, with the incoming SW solar flux, as if originating from a second heat source for the surface. In reality, that flux is part of the net energy loss flux from the surface. All it does is keeping the surface heat loss through thermal radiation down. I know you know this, and I know it doesn't really change your conclusion, but wouldn't it be better to just state this? IR from the atmosphere does not constitute a direct forcing on the surface. It's an INdirect forcing, limiting its heat (net energy) loss by thermal radiation. The global surface of the Earth is always losing, never gaining, heat by thermal radiation. It is simply a matter of how great or small that loss is. This could be more clearly pointed out.Thanks.
SitatscienceofdoomKristian,There's nothing wrong with your way of thinking. You can think of the 2-way radiative exchange as 1 net process or as 2 separate processes. But regardless of the temperature of the atmosphere the surface radiates a given amount according to its temperature. Regardless of the temperature of the surface the atmosphere radiates a given amount according to its temperature. This is important to understand and many people (in the blog world) are confused about it. ... In Figure 4 one might be confused into thinking that you liken the IR 284 W/m^2 coming down from the atmosphere, mainly heated by the surface, with the incoming SW solar flux, as if originating from a second heat source for the surface. In reality, that flux is part of the net energy loss flux from the surface ...Regardless of how you describe it in words, there is no actual difference. The only reason the earth is above the 3K microwave background temperature is because of the Sun heating it. So in this sense perhaps the arrow showing emission of thermal radiation from the earth is misleading, as people might think it is an independent heat source?Understanding the individual fluxes and the net are both important.
SitatKristianSoD says: "Regardless of how you describe it in words, there is no actual difference. The only reason the earth is above the 3K microwave background temperature is because of the Sun heating it. So in this sense perhaps the arrow showing emission of thermal radiation from the earth is misleading, as people might think it is an independent heat source?"That's perfectly fine. I agree. BUT, if you want to determine HOW the positive imbalance (causing warming/net accumulation of energy) at TOA or Earth's surface came to be, then you would have to sepa[ra]te between the two – heat gain from the Sun and heat loss from the Earth. Then the specific terminology you use does become important. Because of the specific thermodynamic mechanisms for warming those terms represent.Is the observed imbalance a result of increased heat gain or of reduced heat loss? The atmosphere reduces the heat loss. It does not increase the heat gain. Only the Sun does. Being an actual source of heat.So, what if we observe increased total heat loss from the Earth's surface and/or TOA during long-term global warming? That means the cause of the imbalance producing the net accumulation of energy in the system cannot be a heat loss reduction, i.e. atmospheric forcing. It will have to be an increase in heat gain, i.e. solar forcing. Will it not?
SitatscienceofdoomKristian...So, what if we observe increased total heat loss from the Earth's surface and/or TOA during long-term global warming? That means the cause of the imbalance producing the net accumulation of energy in the system cannot be a heat loss reduction, i.e. atmospheric forcing. It will have to be an increase in heat gain, i.e. solar forcing. Will it not?...Can you give an example? Can you be specific on your terms because your statement is confusing (identify each term for surface balance and then which one or which combination you believe is the identifier).If you observe heat loss from the Earth's surface then there will be surface cooling. By definition. And the surface emission of thermal radiation at any time will only be due to the actual temperature (and emissivity) of the surface. So I can't fathom your meaning. If you want to separate out solar forcing there is an easy way – measure it via satellite.
SitatKristianSoD, you say: "Can you be specific on your terms because your statement is confusing (identify each term for surface balance and then which one or which combination you believe is the identifier)."I'm not sure I see what's so hard to understand.I do realise that with a positive energy imbalance, there is only ONE real total heat flux and that is going down.But what I'm getting at is the fact that this total heat flux CAN be split into a solar component and a terrestrial component, two net fluxes going in opposite directions.The solar component is the warming one, the Sun being the heat source. The terrestrial component is the cooling one, the ventilation to avoid overheating.So, Earth gains its heat from the net downward solar flux. At TOA or at the surface. At the same time it releases heat (from the surface to the atmosphere or from TOA to space). This is the net upward surface or TOA flux. At the surface this would constitute the sum of the global latent, sensible and net radiative energy fluxes, you know the ~165 W/m^2 [one] that ideally balances the net incoming flux from the Sun.http://earthobservatory.nasa.gov/Features/EnergyBalance/images/surface_energy_balance.jpgAnd at the TOA, it would be OLR going OUT and SWin-SWout=SWnet going IN, you know the ~239 W/m^2 ideally going both ways.We (I, at least) want to know which one of these two component net energy fluxes, the solar one or the terrestrial one, that has been responsible for the observed total positive energy imbalance (solar IN – terrestial OUT).This is the background for my asking: "What if we observe that the total terrestrial net energy flux from the Earth's surface and/or TOA has indeed increased during long-term global warming (let's say the last 30 years)? Doesn't that mean that the supposed warming mechanism of 'the enhanced GHE', restricting the Earth's cooling rate (surface or TOA), simply could not have done the warming?"
SitatPekka PiriläKristian,To me it seems that it's so far impossible to answer empirically your question. The easiest part is the intensity of solar radiation in space. It's being measured continuously and the measurements are accurate enough for this purpose. You can easily find data on total solar irradiance (TSI) from many sources. The Earth albedo is the other factor for the net solar SW at TOA. Its not known as accurately. Measuring it from the satellites is difficult as the whole Earth area should be covered with a limited number of satellites and as also the short term temporal variability should be determined.Similarly it's difficult to measure accurately the total OLR at TOA. Again the satellites cannot do it accurately enough, more and better equipped satellites would be needed for accurate measurements both for OLR and for albedo determination.At the surface accurate measurements of solar radiation are possible at individual points but covering the whole surface well enough is not practical.In absence of accurate enough direct measurements the best we have are the analyses of the type of Trenberth, Fasullo, and Kiehl (2009): Earth's Global Energy Budget. They combine evidence from a wide variety of sources and apply theoretical constraints in building their estimates. The can provide an useful overall picture, but they cannot really answer your question. The inaccuracies of their approach have been highlighted by some recent studies that tell about significant potential errors in their numbers. In particular the values obtained at surface are greatly uncertain.
SitatKristianPekka, SoD, in a January 2011 comment to his own post 'Understanding Atmospheric Radiation and the "Greenhouse" Effect – Part Two', stated: "Imagine if all of the surface radiation was emitted unchanged at the top of atmosphere. (No "greenhouse" effect). Let's say 450 W/m² emitted from the surface and, therefore, 450 W/m² emitted into space from TOA. Now we add a "greenhouse" gas and the radiation leaving from TOA = (e.g.) 440 W/m². The energy leaving the planet has reduced by 10 [->] 440 W/m². This means more heating of the planet, therefore, (by convention), a radiative forcing. So it's more about convention. If less energy leaves the planet, the planet must warm (at least in the short term). So a reduction in radiation leaving is an increase in radiative forcing." http://scienceofdoom.com/2011/01/23/understanding-atmospheric-radiation-and-the-%E2%80%9Cgreenhouse%E2%80%9D-effect-%E2%80%93-part-two/#comment-9154This, in place of a current answer on his part, like your response here (albeit tacitly and implicitly), seems to acknowledge the basic premise underlying my proposition. Yes, if less energy leaves the planet (OLR at TOA - terrestrial component) and the amount of energy entering the Earth system (solar component) remains unchanged over time, the planet must warm. And such a reduction in radiation leaving Earth is 'by convention' an increase in radiative (atmospheric) forcing. If this forcing keeps on strengthening, the warming will endure. But if we DON'T observe less energy leaving the planet over an extended period of global warming, but rather the opposite - if it is observed instead to increase more or less in step with the rising surface temperatures, then what? Then we have global warming which couldn't possibly have been caused by less energy leaving the system - because more, not less, energy has been leaving the system during the warming. There is no way, then, that the atmosphere has been doing the work. The atmosphere has been doing its best to COOL the Earth, to keep the pace and to catch up with the imposed positive imbalance. How? By speeding up the global water cycle. Higher rates of evaporation and convection to spread the accumulated (mainly tropical) surface heat around the globe and to lift it ever more efficiently up and away from the surface towards TOA and space, warming the troposphere along the way. So what would have caused the energy imbalance in this scenario? If not less energy OUT. There is only one alternative. More energy IN. From the Sun. Pekka, I would like to see you build a case for OLR at TOA (as measured by satellites - e.g. ERBE-CERES, ISCCP FD, HIRS) not having increased as a function of general surface temperatures since at least the mid 80s, global evaporation/latent heat transfer from the surface of the Earth not having intensified significantly since the 70s and the temperature gradient between the global sea surface and the air layer directly above it not having become steeper since the end of the 70s. If you can do all this, you would have shown that the Earth system has NOT managed to shed more of its incoming net energy (from the surface, through the TOA) as a result of/a response to higher surface temperatures. In line with the atmospheric warming mechanism - restricting heat loss to promote accumulation of heat.
SitatHi, I tried to post a comment (twice) on your blog tonight, but it never showed up. It was meant as a reply to Pekka Pirilä's posting on January 23, 2013 at 7:30 am on the 'Visualizing Atmospheric Radiation - Part Nine - Reaching Equilibrium' thread. Here is my comment in full: [...] Just to let you know ... Regards,
SitatIs it possible that the blogospheric discussions on the greenhouse effect ( at Climate Etc, Science of Doom, etc) have actually slain the skydragons? And John O'Sullivan's threats of legal action that resulted in my removing the skydragon threads from Climate Etc. — has this resulted in the burial of the skydragons and arguments that there is no warming of the earth and atmosphere from CO2? If so, this is a major victory for the blogosphere.
Sitat fra: Jostemikk på januar 28, 2013, 00:21:05 AMEtter ha ha spurt SoD om hvorfor hans innlegg ikke kom gjennom, og SoD tok en "de blir tatt av spamfilteret", har Okular nå nye innlegg på plass. SoD nekter plent å svare på Okulars spørsmål.http://scienceofdoom.com/2013/01/20/visualizing-atmospheric-radiation-part-nine-reaching-equilibrium/For de som vil ha spørsmål/svar om innlegg som ikke kom igjennom, står det om dette i den siste artikkelen til SoD:http://scienceofdoom.com/2013/01/27/visualizing-atmospheric-radiation-part-eleven-stratospheric-cooling/Jeg anbefaler alle å lese det Okular har bidratt med der. For det første er det direkte imponerende, og for det andre er det første gang jeg har sett at SoD har brukt flere dager på ikke å svare på innlegg som i seg selv er nok til å knekke ryggen på hele GAGW-spøkelset, for ikke å si CO2-hypotesen.
Sitat fra: Okular på januar 28, 2013, 00:35:04 AMJa, jeg så det nå også. Jeg orker ikke å bygge videre på noen konspiratoriske tanker og velger inntil videre å stole på at det han sier har skjedd faktisk er hva som er skjedd.Men han svarer fortsatt ikke på spørsmålene eller problemstillingene, nei. Han synes mer opptatt av å 'tune' modellene sine.
Sitat fra: Jostemikk på januar 30, 2013, 11:35:24 AMNå har SoD svart.
SitatKristian on February 2, 2013 at 2:36 pmYour comment is awaiting moderation.Which brings me to your CERES plots.If you recall, I clearly stated that the OLR at TOA cannot be observed to increase DURING WARMING, if the atmosphere is to be responsible for that same warming.Well, there has been no global warming during the lifetime of the CERES satellites (Terra and Aqua).So why would we expect to see any trend resolving the issue in the CERES OLR data? We wouldn't.But CERES wasn't the first satellite project to measure OLR. And I think you know this, even though you stated the following: "The observing systems in place can comment on TOA OLR for just over the last 10 years." Well, I already mentioned several other projects in my last post (to Pekka Pirilä).But before we go there, let's just agree on one thing. Looking at the CERES (anomaly) data, there is no question what controls OLR at TOA: 1) surface temperatures, 2) atmospheric temperature and humidity and 3) clouds, with 1) leading (basically ruling) 2) and 3). The ENSO process is the best way to show this.Loeb et al. 2012:http://download.springer.com/static/pdf/641/art%253A10.1007%252Fs10712-012-9175-1.pdf?auth66=1361044098_e3fc64c10772d7b5c0c6b5f58d0dd0b9&ext=.pdfSusskind et al. 2012:http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012822_2012011737.pdfhttp://i1172.photobucket.com/albums/r565/Keyell/CERES2000-2010trvsgl2-1.jpghttp://i1172.photobucket.com/albums/r565/Keyell/GltempvsOLR_zpse04e4fe7.jpgWith this is mind, let's go back in time.More later ...