A short lesson in simple logic

Posted: December 11, 2012 by Rog Tallbloke in Analysis, climate, Incompetence, methodology, Philosophy

miracleIn his recent thread  ‘ A simple argument supporting a radiative greenhouse effect’,  Tim Folkerts opened with this statement:

This is about the simplest, most intuitive, most irrefutable argument I can come up with for why gases like CO2 and H20 in the atmosphere (“greenhouse gases”) must warm the surface.

He then goes on to attempt proofs of two propositions.

For a given surface temperature, less radiation leaves a world with cool greenhouse gases than a world with no greenhouse gases.

and

A warmer world with GHGs can radiate away the same energy as a cooler world with no GHGs.

However, neither of these support the assertion implicit in the opening statement, that “gases like CO2 and H20 in the atmosphere (“greenhouse gases”) must warm the surface.”

This is a common mode of argumentation from proponents of the radiative greenhouse theory. It contains a common logical error called non-sequitur (it does not follow) which negates it. To Illustrate this, consider the following propositions and the final deduction:

Phil owns a ball
Phil’s ball is red
This ball is red
Therefore this ball belongs to Phil

It’s easy to see that the deduction is a non sequitur. It is also indeterminate. It could be true, but we can’t tell from the available information whether or not it is true.

For the proposition to be true, there would need to be both necessary and sufficient conditions.
The necessary condition in this example is that the ball is red.
Sufficient conditions might be one of the following:

  • All balls belong to Phil
  • There is only one red ball

I’m sure you can think of a few more.

Getting back to climate science and Tim’s claim that “gases like CO2 and H20 in the atmosphere (“greenhouse gases”) must warm the surface”:
The point is that even if having radiatively active gases like co2 and water vapour is a necessary condition for the surface to have the potential to be warmer than the final emission-to-space temperature, it does not follow that it is a sufficient condition for the actuality of that higher temperature.

Just because Co2 and H2O cool the planet by radiating to space and this happens to open up the possibility for the surface to get warmer, it does not follow that it is the co2 and the H20 that do the warming. Indeed, there are several reasons why we might come to the conclusion that they can’t.

Radiative greenhouse proponents tend to react to this startling revelation in one of three ways.

They don’t comment further on that discussion thread.

or

They change the subject.

or

They reframe the argument.

This last one is the most interesting. One example goes like this:

But what else could it be?

(tm Phil Jones)

As if leaving this question hanging in the air was somehow sufficient to win the day. The answer is of course:

Several other things.

.

Comments
  1. adolfogiurfa says:

    Seas should be considered as part of the atmosphere, as it is there where evaporation occurs. There is an obvious dynamics of exchange there more than in any computer model.
    Remember the “hot bottle” theory?. Water has the greatest heat capacity….

  2. Entropic man says:

    This post is rhetoric, not science.

    [Reply] Your comment is rhetoric, my post is logic.

    There is a place for concise scientific language, with every word chosen for clarity and precision of meaning. That is in a published paper in a scientific journal. This allows accurate communication to other scientists, but makes it difficult for the lay reader to understand.

    [Reply] Feel free to post a link to a peer reviewed paper which explicitly proves that airborne co2 and H20 warm the surface to 288K

    Tim Folkert’s piece was intended as a simplified discussion for a non-technical audience, written in language to match.

    [Reply] It makes illogical claims, as pointed out in my post.

  3. Stephen Wilde says:

    “Remember the “hot bottle” theory?. Water has the greatest heat capacity….”

    Hey, someone remembers :)

    http://climaterealists.com/index.php?id=1487&linkbox=true&position=7

    “The Hot Water Bottle Effect”

  4. Entropic man says:

    tallbloke

    “[Reply] Feel free to post a link to a peer reviewed paper which explicitly proves that airborne co2 and H20 warm the surface to 288K”

    http://www.geo.utexas.edu/courses/387h/Lectures/chap2.pdf

    http://depts.washington.edu/amath/research/articles/Tung/journals/solar-jgr.pdf

    http://www.agu.org/pubs/current/si/links/2005GL025539.pdf

    [Reply] None of these prove what I requested.

  5. mitigatedsceptic says:

    Good one – thanks!

  6. Tim Folkerts says:

    Wow. Its like a hydra! I’ll get back to this later, but it did make me smile. :-)

    [Reply] Just like you’ll get back to refuting the ocean hypothesis. Sure.
    ‘Folkerts unwritten rebuttals’ a slim and unconvincing tome.
    ;)

  7. oldbrew says:

    ‘But what else could it be?’

    Maybe there’s an external power source, erm…let’s think…:-)

    Maybe temperatures even varied before the industrial age, is it possible?

  8. Hans Jelbring says:

    Tallbloke, I love your example and it clearly shows the problem of getting full information about a complex system. Since we are always surrounded by such systems in everyday life we need to be reductionistic, which means to simplify the system or the understanding of a system to get things done at all. Unfortunately, reductionism is not a good method in science if not carefully explained why it might work. The influence of the parts of the systems that are abandoned might be possible to estimate as an example. The problem greatly magnifies when there exists or can exist parts of the system that are unknown to the investigator as is the climate system. To blame climate change on just one factor, human carbon dioxide emission is an example of extreme reductionism and deeply unscientific.

    From a dictionary: REDUCTIONISM
    An attempt or tendency to explain a complex set of facts, entities, phenomena, or structures by another, simpler set: “For the last 400 years science has advanced by reductionism … The idea is that you could understand the world, all of nature, by examining smaller and smaller pieces of it. When assembled, the small pieces would explain the whole” (John Holland).

    (A terrible statement in my opinion which might be one explanation of the sad state of today science. HJ)

  9. Stephen Wilde says:

    A specialist being a person who comes to know more and more about less and less.

    Hence the appalling knowledge gaps in the minds of climate specialists.

  10. Tim Cullen says:

    Great article.

    Hans Jelbring says: December 11, 2012 at 3:12 pm

    Well said.

  11. adolfogiurfa says:

    @Stephen Wilde: The problem we are facing now is that your “hot water bottle effect” is becoming an “Ice bag effect”, and I am not referring to your local northern hemisphere winter but to cold temperature anomalies in the southern seas:
    (An precisely in front of Ecuador -Equator- where the heat was supposed to be)

  12. Steveta_uk says:

    For a given surface temperature, less radiation leaves a world with cool greenhouse gases than a world with no greenhouse gases

    Roger, are you not in fact arguing with the above statement – i.e. that for a world for which less radiation if leaving due to cool greenhouse gasses, we cannot infer anything directly about the surface temperature.

    It seems to me that if the above statement is true, then a higher surface temperature is required to radiate the same total.

    However, if, as you contend, all that the external IR profile of the planet tells you is the conditions where (the bulk of) the radiation comes from, then it cannot be used to directly determine whether GHGs cause the surface temps to be raised or not.

    I think….

  13. tallbloke says:

    Steve:
    For there to be a difference in the amount of radiation leaving, the worlds would have to be at a different distances from the Sun. This is a prime example of Folkerts obfuscating.the issue, and trying to bamboozle people who don’t have the time to think through the implications of his statements.

    Why start arguing about two planets that are at different distances from the Sun when we are discussing the difference in surface temperature between planets with and without greenhouse gases? This just confuses the issue.

    If we restate his proposition for two planets, one with and one without GHG’s at the same distance form the Sun, we get:

    “For a given distance from the Sun, a higher surface temperature can be achieved on a world with cool greenhouse gases than a world with no greenhouse gases.”

    But all this claims is that greenhouse gases in the atmosphere are a necessary condition for a surface temperature that exceeds that which could be achieved by a planet with no GHG’s. It says nothing about whether or not the greenhouse gases are also a sufficient condition for the achievement of the higher temperature.

    And in any case, I don’t think his proposition is safely proven. Consider a planet with a low mass atmosphere of high vapour content and a consequently high albedo, reflecting most insolation back to space.

  14. Bryan says:

    There is a further oversimplification of IPCC ‘science’ are guilty of and that is to imply that the presence of a colder body must always make a warmer body warmer than ‘it would otherwise be’.

    This is because it is assumed that ‘the surroundings’ are colder than the colder body.

    If the surroundings are warmer than the colder body this is no longer true.

    ……………………………………………………………………………………………..

    What about the situation where we can disregard the surroundings?

    A hot hollow sphere has a cold object placed at its centre.

    Does the radiation from the colder object ‘warm’ the sphere?

    I don’t think so!

    Tim why does the backradiation being fully absorbed not increase the temperature of the sphere?
    Look forward to your considered reply although the unanswered backlog is getting rather large.

  15. erschroedinger says:

    [snip]
    Have you nothing better to do than post nonsense?

    [Reply] Every letter answers itself, or questions its author.

  16. Arfur Bryant says:

    Logic has always been the enemy of the warmist dogma. They can claim as much scientific authority as they want but their consensus science will always come a poor second to true logic. Fundamentally, science should make sense.

    Hans Jelbring had it right when he said:

    ["Unfortunately, reductionism is not a good method in science if not carefully explained why it might work. The influence of the parts of the systems that are abandoned might be possible to estimate as an example. The problem greatly magnifies when there exists or can exist parts of the system that are unknown to the investigator as is the climate system."]

    Big picture stuff, guys…

    There was an ‘Atmosphere Effect’ in 1850, before the IPCC start of ‘accurate data’ and before the term ‘Greenhouse Effect’ was first used.

    If one accepts that the current ‘GHE’ is 33C (I know not everyone here agrees, but thats what the warmists accept), then the ‘AHE’ in 1850 was 32.1C (as there has been a warmist-accepted 0.9C rise since 1850). Logically, therefore, the amount of radiation being emitted by the much lower concentration of radiative GHGs in 1850 would have to be very large in order for the 32.1C (and now the 33C) to be mostly – or significantly – caused by radiation. Logically, therefore, the observed significant increase in radiative gasses (CO2, CH4 etc) would have had to produce a much larger increase in temperature than has been observed.

    Logically, thermal inertia lag is a demonstrably failed argument. (14 years of no warming.)
    Logically, positive feedbacks is a demonstrably failed argument. (Ditto.)
    Logically, natural forcings/factors have always had the ability to produce the warmings, coolings and flattenings we have observed since 1850. (14 years of no warming in spite of a theorised acceleration of anthropogenic effect.)

    No amount of pseudo-science excuses will make up for this simple fact.
    No amount of belief in the warmist mantras will make it happen without supporting, evidential data – which hasn’t happened.

    The theory (of radiative greenhouse warming) is wrong. Change the theory.

  17. Kristian says:

    “A warmer world with GHGs can radiate away the same energy as
    a cooler world with no GHGs.”

    It’s not really about how high the surface temperature needs to be in order for the Earth system to be able to radiate a certain amount of energy to space with ot without GHGs in the atmosphere.

    The Earth surface has an average global heat loss of ~165 W/m^2. The Earth system (at TOA) has a heat loss of ~240 W/m^2. The net energy flow going up is added to all the way from the surface to TOA (+75 W/m^2 all in all). It’s simply ridiculous comparing an SB-calculated virtual energy flux component (OUT) based on the physical temperature of the global planetary surface (~398 W/m^2) to a NET energy flux at TOA (240 W/m^2). For crying out loud, the Earth surface is not a blackbody in a vacuum. It is bordered by an atmosphere cooler than itself, yet still containing a lot of heat, most of it put there from the surface itself, mainly through latent heat transfer and convection. The continuous energy exchange between two warm objects in thermal contact makes the one-way fluxes between them basically meaningless. It’s all about the net flux – the transfer of heat. The mean global heat transfer from the Earth’s surface to the atmosphere, always trying to balance the total energy coming in from the Sun, is split between latent heat transfer (according to the new Stephens et al. 2012 study, a mean power flux of 88 W/m^2), sensible heat transfer (24 W/m^2) and net longwave radiation (52.4 W/m^2 – of which 20 W/m^2 pass through the all-sky atmospheric window).

    If the global warming we’ve seen since the last part of the 70s was really due to an ‘enhanced greenhouse effect’ as described by the AGW hypothesis, then we should not be observing an increasing total heat loss from the Earth surface during the warming. This is simply because that is how the effect of an atmospheric rise in GHG concentrations would induce warming. And in no other way. An ‘object’ that is cool cannot cause an adjacent warm ‘object’ to become even warmer in any other way than limiting its heat loss (given a constant external energy input) by forcing it to release its received heat less readily.

    The enhanced greenhouse effect allegedly does this by reducing the temperature gradient between tropospheric strata going from the raised effective emission height of the Earth all the way down to the surface. That way, in a snapshot the surface heat loss is subdued because of the smaller temperature gradient upwards. There’s an imposed energy imbalance and the surface needs to raise its temperature to be able once again to balance the energy going out with the energy coming in.

    In that way, in tiny little increments and very gradually, following the increase in atmospheric GHGs, the surface heat loss is initially forced slightly below the IN-OUT balance threshold and then from this position work its way back up again to the IN-OUT balance threshold by raising its temperature.

    But the heat loss at the threshold can never be exceeded in this way. Then the surface as a whole would loose more heat than it did before the start. And it would cool.

    If the warming rather originated at the surface, however, this would all be different. Simply because it’s on the opposite side of the heat transfer (net energy flux) arrow between the two layers from the atmosphere.

    That’s why, if we observe a total increase in heat loss and/or we see evidence of a widening rather than a narrowing temperature gradient between the global surface and the atmospheric layer just above it, then we would know the warming is not due to AGW. The atmosphere couldn’t have done it. The warming would have to had started at the surface itself, being propagated upwards to TOA.

    And, lo and behold! This is exactly what we do observe in the real world.

    So, if there is evidence that the enhanced greenhouse effect is null and void, that putting more GHGs into the atmosphere does not affect the mean global surface temperature, then why would the GHGs already there from before affect the mean global surface temperature?

    I sincerely hope you can tell me where my argument fails …

  18. P.G. Sharrow says:

    @ Tallblokesays;”Consider a planet with a low mass atmosphere of high vapour content and a consequently high albedo, reflecting most insolation back to space.”

    Low mass, high vapor content, atmosphere. Emmm sounds like a contradiction to me. At least if that is water vapor. I thought we had proved that a low mass atmosphere had to be too cold to hold much water vapor.

    Well anyway you should check out:

    http://chiefio.wordpress.com/2012/12/12/tropopause-rules/

    Our friend EMSmiths’ latest offering. pg

    [Reply] Thanks PG! I’ve reblogged Chiefio’s post here.

  19. Richard111 says:

    adolfogiurfa says: December 11, 2012 at 5:02 pm

    Thanks for that link to the sea surface anomaly.
    Summer solstice for SH in ten days and the southern seas are still cool!

  20. Hans Jelbring says:

    P.G. Sharrow says: December 12, 2012 at 5:38 am

    The post by EMSmith is much superior to the IPCC model based versions. It It is well worth to analyse and ponder about many aspects Smith is presenting. He has understood the importance of regional variations, both latitudinal and vertical. He points of what processes are causing energy flows in the troposphere adn stratosphere is great (mixing processes)
    Having said that there are some very important aspects he is missing.

    o The existence and actions of Mobile Polar highs are very important. The mechanism
    that drives them is for real and not recognized by mainstream meteorologists.
    o He argues as if all emisson from the atmosphere is produced by gases. Dust particles, ice and snow particles in the air radiate as black bodies and these do not show up in his “emission” image which is very important for his reasoning but less good for showing the real sources of emission into space.
    o He should use the concept of total energy per mass unit in the atmosphere instead of temperature
    when discussing the separation between the tropshere and stratosphere. He does not recognize the importance of the fight for energy equilibrium per mass unit in the troposphere (second law of thermodynamics)
    o He is missing the influence of extraterrestrial factors which is a must for understanding long term climate change but he is not alone in this respect.

    I certainly favour Smith´s approach of wanting to discuss the whole picture (including semantic problems) of atmospheric processes to the limit of what is known to him and a few others.

  21. Bart says:

    It would be better in many cases if people would speak of energy flux or power, rather than just “energy”. In the simple “greenhouse” model, a state is reached in which energy flux in matches energy flux out. Any energy retained or lost during the balancing interval will serve to heat or cool, respectively, the surface from what it otherwise would have been.

    It really makes no sense to say a “warmer world with GHGs can radiate away the same energy”, as radiating some quantity of energy is an event, whereas we are speaking of an ongoing process.

    As I say, this is the “simple” greenhouse model. It fails to be persuasive with regard to the Earth because, as the blog entry states, this is a complex system, and there are a lot of other processes going on, some of which may resist or counteract the simple GHG dynamic.

  22. tallbloke says:

    Hans:
    I think E.M Smith did refer to MPH’s in his article here:

    “Along the way, a very cold stratosphere, dropping down the winter Polar Vortex, will cause a fairly strong warm / cold range between poles and the equator. That will cause a ‘loopy jet stream’ as the blobs of cold arctic air slide south and plenty of winter storms as the equatorial heat heads north. Only running down when we’ve cooled the tropics enough to balance the colder poles.”

    A friend has sent me Leroux’s two books. A fabulous early christmas present. So you can expect posts discussing his work once I’ve had time to read parts of them over the Christmas holiday.

  23. tallbloke says:

    Bart: Thanks! Your endorsement means a lot to me. There is all sorts of sloppy language used in climate debate, which leads to endless confusion and argument. I sometimes think it is ‘subconsciously deliberate’ on the part of those who have to obfuscate their presentation in order to avoid the obvious!

  24. Tim Cullen says:

    Hans Jelbring says: December 12, 2012 at 8:59 am

    My perspective is similar… but I have a few caveats to that statement.

    Fundamentally, the consumers of “settled science” are being woefully misled by the professionals in “white coats”… its got to the point where it’s also impossible for the discerning consumer to differentiate between “the doctors” and “the patients” in the insane asylum called “settled science”.

    Luckily, there are many “discerning consumers” on the internet who are rediscovering the scientific method and reviving the traditional role of “gentleman scientists”.

    However, these “gentleman scientists” are rather conflicted.

    On one side the “gentleman scientists” are trying to address the reductio ad absurdum arguments of “settled science”… this is no easy task when the “inmates” have taken over the “asylum”… in many ways this probably mirrors the problems “medical practitioners” encounter when a society believes in the power of “witch doctors”.

    On the other side the “gentleman scientists” are actually trying to move forward with the scientific method so they can better understand the real world.

    I perceive E.M. Smith’s article within this context… it addresses the “settled science” and it also lays down some markers for other “gentleman scientists” to research… Marcel Leroux also laid down some markers worthy of further investigation.

    Overall, we are still chasing the truth… and probably always will be… but at long last the focus of the debate is beginning to head in the right direction through the application of the scientific method.

    That is my perspective as a “cynical consumer”.

    I also found it very interesting to read E.M. Smith’s previous article:

    Do temperatures HAVE a mean?

    http://chiefio.wordpress.com/2012/12/10/do-temperatures-have-a-mean/

  25. Tim Folkerts says:

    Actually, I don’t think I will get back to addressing this. The entire top post in a strawman, so there is really no point in even starting.

    As for the ocean, the GHE allows things BELOW the GHGs to be warmer than the effective radiating temperature (~ 255 K for earth). So the ocean GHE would allow the water UNDER the ocean to be warmer than surface, but it cannot (by itself) raise the temperature of hte topmost layer to a temperature above this ~ 255 K limit (or else the topmost layer would be radiating more energy out than it is receiving from the sun).

  26. adolfogiurfa says:

    @P.G.: That place DOES EXIST!, it´s the city where I live. Due to cold waters in the pacific, we are having a cold springtime, with completely covered skies. This city is called the “grey sky city” as 9 months out of 12 are covered with low clouds, where humidity in winter time usually over saturates producing a fine drizzle.
    What is it happening now?. As living in El Niño 1+2 area, we have been taught at the school, that there were two sea currents: One cold current coming from the south, which is called the Humboldt´s current, the other, when El Niño happens, it is a warm one and it comes from the north….Well, that was until these “interesting times”; as you can see in the following map, in the last few weeks there has been a cold temperature anomaly, extending from NORTH to SOUTH:

  27. tallbloke says:

    Heh, Tim takes option one (don’t comment further on that discussion thread) and justifies it with a poor excuse based on a misunderstanding of basic physics, thus hybridising it with option 2 (change the subject).

    The basic point of logic stands, no matter how Tim tries to wriggle around.

  28. Tim Folkerts says:

    Bart says: “It would be better in many cases if people would speak of energy flux or power, rather than just “energy”….
    It really makes no sense to say a “warmer world with GHGs can radiate away the same energy”, as radiating some quantity of energy is an event, whereas we are speaking of an ongoing process.”

    It would be EVEN better in many cases if people would speak of energy flux integrated over a specified surface and integrated over a specified time.

    The point is that there is always a balance between saying things
    * in the most mathematically accurate way
    * in the most concise way
    * in the way most people will understand.
    Furthermore, that balance varies from person to person.

    You wanted a more mathematically accurate way, but you didn’t want the MOST mathematically accurate way. That’s cool.

    In context, it was clear to you that I meant “total thermal IR energy radiated out from a given amount of area in a given time”. It is sort of a Catch-22. If a person understands surface integrals of heat flux, then then don’t need to be told this is what I was doing; if a person doesn’t understand flux, then explaining it is a blog post will be futile and simply saying “energy” will mean more to them anyway.

  29. “What else could it be” … the difference between real science and this “alternative science-like .. thing”

    Real science doesn’t care if it doesn’t know because real science considers most things to be unknown and only a small amount of information reaches the standard to be considered “science”. This post normal clap trap alternative … hey it’s warm init.

    … has to have an answer for everything, and when it doesn’t have a real answer it comes up with something utterly stupid.

  30. Tim Folkerts says:

    Yes, the basic point of logic stands .. but it is unrelated to my arguments. :-)

  31. tallbloke says:

    Tim F says:
    …the basic point of logic stands .. but it is unrelated to my arguments

    Insofar as your arguments are unrelated to reality, I agree. ;)

    David Cosserat has made an excellent contribution on your thread by the way. Should clue you in about the non-causally-effective nature of LW radiation in the lower troposphere.

    http://tallbloke.wordpress.com/2012/12/06/tim-folkerts-simple-argument-supporting-a-radiative-greenhouse-effect/#comment-38020

    This is the real point, it is mass, force and energy that make things happen in the real world, not spectra. In the lower troposphere, the mass of the atmosphere above, the force of gravity acting on it and the energy in the latent heat of vaporisation dominate completely. LW radiation is just along for the ride there.

  32. Max™‮‮ says:

    Yet again I feel like I’m taking crazy pills, Tim, 255 K has nothing to do with reality other than to set a theoretical lower bound for the temperature of a surface which radiates 240 W/m^2.

    A surface at 288 K can radiate that amount if it has .6 emissivity, and a general energy balance is obtained readily at around that value.

    As such it should be easy for you to demonstrate why you think emissivity is higher, shouldn’t it, Tim?

  33. tallbloke says:

    Max, take a look at an aerial view of the ocean. Totally black. Emissivity 0.983

  34. Max™‮‮ says:

    Looks like it varies depending on the wavelength, which wavelengths are you quoting?

    http://cimss.ssec.wisc.edu/patmosx/doc/v5_level2b_data_description.html

    http://www.ospo.noaa.gov/Products/atmosphere/mspps/emisprd.html

    http://www.sciencedirect.com/science/article/pii/S0034425700001085

    You can’t just say “the emissivity of the ocean is .983″ because that only applies to a particular wavelength, if the surface only radiated in a particular wavelength you’d be absolutely correct, but I don’t think the ocean is a gigantic laser, is it? :D

  35. Max™‮‮ says:

    Sorry about double post, but I found a MODIS motherload.

    Should I take that and declare that the ocean emissivity is .7 or lower and the ground is .9 or higher?

    This is why I said there is no universal value from measurements, hence my preference to calculate a value from more easily measured parameters.

    From MODIS it looks like .983 emissivity for seawater occurs at 6, 8, and 12 microns:

    http://www.icess.ucsb.edu/modis/EMIS/html/em.html

    Lots of data! Weee, data data data!

    Whew, look at this one:

    Clay bricks, within the 4 to 14 micron range it goes from .55 to .95+!

    Good thing the only emissions we’re concerned with are in that range, right?

  36. tallbloke says:

    Max: Thanks for your research effort, very interesting findings. I can’t ex[plain the difference between the MODIS plot and the ICESS data. Please keep digging, I just don’t have time to do everything, and I’m in the middle of flashing an E-reader with an Android install to use as a wordpress blogging tool while I’m out in the mountains next week.

  37. Max™‮‮ says:

    I hear ya, basically you can get differences from temperature, wavelength, and angle before you even change the material you’re measuring. Seawater in particular depends strongly on the angle you’re observing at, as you can’t be sure you have a clean signal unless you know there is calm water perpendicular to your sensor.

    In particular the reflectivity of water dramatically changes with the angles involved, that’s why some charts for seawater observations include different measurements from 0 to 90 degrees.

    Then there is the note that all of those are functionally clear sky as far as I can tell, but actual cloud cover varies quite a bit, and functionally subtracts from 0.01 to .2 or more from emissivity depending on the type and height.

  38. Max™‮‮ says:

    Minus the first “in particular”, was distracted while typing…

  39. wayne says:

    Max, glad you are sticking in there. Tallbloke, here is why he’s on to something.

    I really hate to use SoD’s graph but it is the only one I can find that completely tells the story of the ocean’s emissivity.

    Let’s just say the world is all oceans.

    Take a long look at those plots. For one thing we live on a sphere, the sun is only above one small point so the angles and how the angles affect the global mean emissivity is very sizeable. Taking a view from the sun side in space, you have a ring of area between the circular horizon all around the edge of the sphere and inward to 15 degrees. That’s the top plot and there is one lot of area that would use that emissivity of about 0.60. Then do 85 to 70 degrees. Not as much area there but emissivity would be between 0.60 and 0.85, avg. 0.725. Only the tiny area where the sun is directly above and at 10 microns would the emissivity be 0.99.

    Also, look how the emissivity drops at lower frequencies below 10 microns. Did you know that at 288K by the emissivity-less SB between 10 & 1000 microns 294.6 W/m2 radiance lies in that range and only 96.3 W/m2 is between 0.1 and 10 microns? So you have to also play that in, which also lowers the emissivity. I bet that 0.88 stated above is pretty close for the entire world’s average emissivity.

  40. Max™‮‮ says:

    That’s reflectance, btw: http://scienceofdoom.files.wordpress.com/2010/12/sea-surface-emissivity-sidran-1981.png

    Not sure why it cut that off in the large version.

    Had to SS these from previews since the sites are behind paywalls I think:

    Simple values aren’t easy to give for such a complex measurement.

    I like to call it spike emissivity for a single point/subset of the spectrum, and spectral emissivity for the full span of values, but a full value is difficult to give too. At least it’s not as hard to average as temperature is.

  41. wayne says:

    OT but, while I have my nifty Radiance 3.0 program fired up, here’s a tidbit of information.

    Take the 288K Planck curve. These are the precise wavelengths (µm) that equally divide the radiation into some easily used eighth portions.

    [8th] 8.04 µm
    [4th] 10.06 µm
    [8th] 12.02 µm
    [1/2] 14.26 µm
    [8th] 17.12 µm
    [4th] 21.35 µm
    [8th] 29.55 µm

    You would be led to believe that the eighth from 14.26-17.12 rules the entire world! ☺

  42. Max™‮‮ says:

    Well, that’s not off topic if we’re trying to get Tim to read it.

  43. wayne says:

    Max, I should have mentioned the reversal there. But isn’t the absorbance the one’s complement of the reflectance? I was careful to flip the notion. α = 1 – R, transmission = 0, and absorbance = emittance (Kirchhoff) when static. I think you can still use those plots to get much closer.

    That is why I always emphasize that it is the “effective” global emissivity when we are speaking of the world as a whole, not just the surface type’s emissivity from straight above.

  44. wayne says:

    Oops. On second thought of that plot Max, I believe that was a big mistake on my part, in the case of longwave, all is upward. What was I thinking? ;) Happens everytime I try to hurry through.

  45. Max™‮‮ says:

    Well, SoD had the plot cut off the reflectance note, I only noticed it because I had seen it in the google image results.

  46. tallbloke says:

    Max: Heh, good spot. Naughty S.o.D.

    Wayne: Could it be that Max’s MODIS plot is right, and the ICESS plot cunningly includes some formulas that includes latent heat and conduction as a ‘LW equivalent’?

    Angles are important. But the surface of the open ocean is ruffled by wind more often than not, so obliquity effect isn’t a straightforward calculation. Also, waves can reflect light into the next wave crest. Simple it aint.

  47. Bart says:

    Tim Folkerts says:
    December 12, 2012 at 1:35 pm

    “It would be EVEN better in many cases if people would speak of energy flux integrated over a specified surface and integrated over a specified time.”

    As I indicated, I was speaking of energy flux in time, a.k.a. power, already integrated over space. I specifically eschew the “integrated over time” bit because, as I said, that is an event, not a process, and the process we are looking at is the balancing of inward and outward flux in time.

    When you speak of energy, people get confused and think there can be no excess energy retained if balance is merely restored. But, if you are balancing energy flux, you can still integrate an excess of retained energy.

    This seems surprisingly difficult to explain, possibly owing to the time of night. Hopefully, what I have stated is clear enough to get my point across.

    In any case, the simple GHG model, as I indicated, is not sufficient to establish that additional CO2 should result in significant warming for a complex system such as the climate of the Earth.

  48. wayne says:

    I found that last tidbit so useful myself… I ran another for the sun.

    Take the 5773K Planck curve of the solar radiation; these are the precise wavelengths that equally divide the radiation into some easily used portions of one-eighths.

    [8th] 402.8 nm – at dark violet
    [4th] 501.9 nm – at bluish green
    [8th] 599.8 nm – at yellowish green
    [1/2] 711.5 nm – at mid red
    [8th] 854.3 nm – near infrared
    [4th] 1.065 µm – near infrared
    [8th] 1.475 µm – near infrared

  49. Max™‮‮ says:

    That is indeed an interesting presentation, it’s the sort of thing that feels like it should be brought up more, strange how it isn’t, huh?