A Note: Global Warming Threads

Discussion in 'Earth Science' started by Tristan, Aug 27, 2004.

  1. Andre Registered Senior Member

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    889
    And exactly that is the flaw. Let alone using a linear operator (factor 4 between area and diameter of the sphere) to a non linear relationship (4th power). Again if you apply Stefan Boltzman, unedited with the spurious factor 4, and at albedo 0.3 (which is including clouds, which are non present in the null hypothesis) then you get a value of 88 degrees celsius. If you use moon albedo of 0.12, Stefan Boltzman returns 381.21 K or 108 degrees celsius as the equilibrium temperature in the zenith point where the full solar flux, all 1360 w/m2 hit the surface momentarily, and that is the forcing factor of the convection. Not the factor 4 division that gives -18C everywhere on the planet.

    It does not, by any means, earth is allowed to cool as much as it physically has to, emitting low freq radiation to space, totally unrestricted by the missing greenhouse effect. However the cooling earth surface does not effectively cool down the atmosphere, except for the lower most boundary layer, due to the lack of negative convection.
     
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  3. iceaura Valued Senior Member

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    There isn't any. You have yet to make a thread relevant argument.

    A planet without wind in its atmosphere (a surface evenly heated, somehow). A gas that emits no radiation into space when heated. And the connection with the calculated effects of rapidly and dramatically boosting the CO[SUB]2[/SUB] concentration of the Earth's atmosphere is what?
     
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  5. Trippy ALEA IACTA EST Staff Member

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    Is it? I had exactly the same thought when I initially read that, then wound up coming to the conclusion that maybe it wasn't so inappropriate after all.

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    Yes, I know I'm looking at the 2d projection of a 3d object, however to some extent, that's the point - so, effectively, is the sun.

    From a 3d perspective the poles receive less energy because they are effectively inclined at an angle to the sun, and so receive the solar constant multiplied by the cosine of the angle from the sub solar point in terms of insolation per meter[sup]2[/sup].

    From a 2d perspective the poles present less area on the projection and wind up receiving the same total energy they would if it were a 3d treatment.

    Right, but you forgot to take into account the fact that the earths surface is curved and so not every point on the earths surface recieves the same amount of insolation - it varies as the cosine of the angle from the sub-solar point.

    Incidentally, I think your albedo may be wrong. Here's a map of the clear sky albedo of the earth:

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    That suggests a flaw (or flaws) in your model (or model treatment) more than anything else. Which leaves me to wonder a couple of things which I'm not sure I have the time to go into right now.
     
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  7. Andre Registered Senior Member

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    889
    I guess it would help if you could point out what exactly is not logical. So we could address that.

    Where exactly is that stated? Could you please quote? Incidentely, anybody noticed that the wind has a tendency to die down in the evening? The reason for that is that ground inversion again. Cooling air stays put by it's higher density and won't move easily by less dense warmer air aloft, that's basic meteorology. This means that there is not a lot of vertical mixing of air during clear nights.

    But even if there was, low level turbulence, mixing air on earth is limited to a few 100 feet, see also wind shear

    How much does nitrogen N2 emit when heated to a few dozen degrees?

    Maybe there are a few problems there. Also what is the empirical evidence of (or even support for) boosting CO2 concentrations on the earths atmosphere?
     
    Last edited: Nov 12, 2013
  8. Andre Registered Senior Member

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    889
    Please reread what I stated, I only talked about the point in zenith, directly under the sun, that's your main convection engine. I did say that the sunny side up received anything from 0 to some 1360 W/m2. But there is only one point that gets all the 1360 w/m2 at a time and it travels around the earth in 24 hours.


    Please reread, I'm fine with any albedo from the normally used 0.3 to the moons 0.12. giving equilibrium temps between 88 and 106 Celcius.

    Actually pick any point you want here:

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    excel source
     
    Last edited: Nov 12, 2013
  9. Trippy ALEA IACTA EST Staff Member

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    I got that the first time around, now re-read it and understand my point - that is that I had the dame thoughts initially, but subsequently came to the conclusion, for the stated reasons, that the treatment using a flat circle wad accurate, the corollary of which is that I believe your factor of 4 is in error.
     
  10. Andre Registered Senior Member

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    889
    Not sure what you intent to say, not sure if we agree or not but the factor 4 is in error, so maybe we agree on that I don't know.

    And again the reason for that erratic factor is that the solar flux hits the earth on a disc diameter with an area of pi*r^2 but it is emitting that radiation from a sphere with an area of 4*pi*r^2. That's where the factor 4 is smuggled in and that gives a uniform -18C all around the sphere, which is considered a perfect black/grey body with a specific heat of zero and a perfect conductor distributing the thermal energy evenly over it's surface, instanteneously. Well the earth is closer to a perfect insolator and the heat staying where it is.

    Now look at the moon. Is that anywhere near a uniform temp of minus whatever in conformity with it's albedo?
     
  11. Trippy ALEA IACTA EST Staff Member

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  12. Andre Registered Senior Member

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    889
    Thanks, indeed when we get to quantify this greenhousegas-less null hypothesis, the proper albedo needs to be quantified. No doubt.

    Anyway, up to now I have been missing the real valid point against this null hypothesis. That is, if you start with an atmosphere-less earth like the moon, or you take the inert non-GHG atmospheric earth, there is no difference for insolation and hence for average warming up of the earth surface. Actually as long as there is no thermal equilibrium the earth temp of the inert atmosphere is actually lower because it loses energy to the convection process.

    That's -no doubt- very true.

    However I never talked about the actual surface temperature but always about the thermal energy in the atmosphere. Also essential is that what we loosely call surface temperature as in global warming, is actually the lowest atmospheric temperature at a height of about 1.5 meters. When you walk barefoot in a desert or you stay a night in an igloo, then you know that those two are not always the same. On earth the thermal radiation tends to even out those differences but those are absent in the non-radiative null hypothesis and the difference between actual contact temperature of the surface and atmosphere at 1.5 meters height may be substantial. But the latter is what you consider "surface temperature".
     
  13. iceaura Valued Senior Member

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    24,295
    You have not provided the active hypothesis, for which your bizarre and otherwise unmotivated perpetual motion analogy atmosphere there would provide the basis of the null hypothesis you haven't got around to providing either.

    So the whole thing is an irrelevancy, designed to avoid discussing the actual situation - a dramatic and continuing anthropogenic boost in the atmospheric CO[SUB]2[/SUB] concentration, and the likely consequences of that circumstance.
     
  14. Andre Registered Senior Member

    Messages:
    889
    Could you please substantiate why it's bizarre and unmotivated? Actually, physics is never motivated. I'd be very interested to hear what counteracts the one way ony heat pump of convection, barring outradiation.

    Could you please indicate where exactly we see evidence that increase of CO2 concentration is confirmed to have dramatic consequences?

    And also, wasn't there something with a 17 years Santer norm and the lack of warming for 17 years in the RSS series?
     
  15. Trippy ALEA IACTA EST Staff Member

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    10,890
    I intend to reply anf to reply in depth, however, I am currently at work and can not justify spending that much time typong on my phone.
     
  16. Trippy ALEA IACTA EST Staff Member

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    10,890
    First off, let me ask you something Andre - do you understand that a disc with the radius of the earth intercepts the same total amount of solar radiation as the Rart does?
     
  17. Andre Registered Senior Member

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    889
    Not sure what you are getting at. Rart? Could it be that this post went unnoticed:

     
  18. Trippy ALEA IACTA EST Staff Member

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    Earth, it was a typo. And no, the post did not go un-noticed, I'm endeavouring to address it, but first I need to completely understand where we have agreement and where we do not. You seem to be objecting to the spurious factor of four you keep referring to, and so I ask you: Do you understand that a disc with the radius of the earth intercepts the same total amount of energy as the earth itself? (The difference being in how it is distributed accross its surface).
     
  19. Andre Registered Senior Member

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    889
    I hoped that my post would have made it unambiguously clear that this is very basic and that's exactly what I am telling. However the problem is the big difference between a theoretical black/grey body and a real planet and why you can't do much with an average factor 4 value, which cancels reality of a diurnal cycle.
     
  20. Trippy ALEA IACTA EST Staff Member

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    10,890
    I'm glad that you edited your post, I much prefer the tone of this one to what I originally read.

    Look, what it boils down to is this. I'm a pedant by nature who is generally short on time, and so, for whatever reason, I'm getting conflicting messages for your posts, with the net result is that while you may feel your posts are unambiguous, I am finding them ambiguous to some degree.

    I could explain why, but I don't really have time for that at the moment, but I might this evening (my time).

    So rather than risking inferring incorrectly whether or not you agree with the statement, I am asking you to, for the moment, set your concerns about non-ideal, non-isotropic behaviour, and the anisotropic nature of insolation at the earths surface and tell me whether or not you agree with the statement that a disc intercepts the same total energy as a sphere of the same radius? It's a straight forward question requiring a yes or no answer that gives me information I need so that I can determine where I need to start my reply to you.

    I understand that you have concerns around the fact that the distribution of energy, and therefore temperature is anisotropic.
    I understand that you have concerns about the fact that the earth does not behave in an ideal fashion when considering the simple equation P[sub]out[/sub]=P[sub]in[/sub].
    I understand your concerns in relation to the Diurnal cycle - and that's without even going into your concerns regarding atmospheric dynamics.

    What I am asking you is to answer in a straight forward way, yes or no, whether or not you agree with the statement that a disc will intercept the same total energy from the sun as a sphere of the same radius.

    I'm sorry if you find that question insulting, however, one thing that my life has taught me is never to take assumptions for granted. I have met some otherwise amazingly brilliant individuals who have stumbled over what I would otherwise consider to be some incredibly basic problems. Professors of chemistry, for example, who could not tell me how to test for the presence of Oxygen in a gas discharge from a chemical reaction - something any student who has completed highschool science should be able to tell you.

    Please, I have endeavoured to show you the courtosey of addressing your posts in full, humor me and return the favour by answering the question.
     
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    I like to answer too, with some clarifications. For the solid sphere and disk ( No atmosphere) yes they will intercept the same flux, but due to normal absorption almost always being greater that non-normal absorption, the disk will absorb more energy.

    In concept, however, if the disk is say 5% of the sphere radius thick and both have the same atmospheric mass (as also a 5%of R thick "rim" of uniform density around the solid part of the disk) then it sunlight striking it will just pass thru - not be absorbed but some of it would be refracted by the spherical real atmosphere's vertical density gradient.

    For example the setting sun on earth as its last visible part disappears had "geometrically set" about 8 minutes earlier (if memory serves me correctly). It is the same effect that make the setting sun appear wider than it is tall - out of round. I.e. for about 8 minutes the solid part of the sphere is with an effective cross section slightly larger than its real diameter has. However, I think the angular dependence of the absorption coefficient would in almost any imaginable case make the disk (nearly normal incidence with the surface as sun is only ~0.5 degree diameter) would dominate - disk absorbs at least 5% more as a quick guess for typical surfaces found on Earth.
     
  22. Trippy ALEA IACTA EST Staff Member

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    10,890
    No, this is wrong. The total energy absorbed is the same in both cases, as indicated by the fact that they both intercept the same amount of flux. What differs is the density of the energy at the surface as measured in w/m[sup] 2 [/sup]
     
  23. iceaura Valued Senior Member

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    24,295
    As always with this bullshitter - dodge the question, change the subject, attack the questioner.

    Because you haven't posted a hypothesis or an argument that connects it to the thread, it's a screwed up description of an incoherent irrelevancy, and you are going to just change the subject if cornered, while repeating your supposed conclusions from it after enough time that naive readers can't just scroll up on the same thread and bust you - - like this:
    No, there wasn't. You got cornered (the claimed 17 year lack of warming was a contrived falsehood straight from the popular book "How To Lie With Statistics", and you had no argument anyway) and when confronted with that you changed the subject - until now.

    It will not stop - it's why he's here. An appropriate forum might be pseudoscience, politics, somewhere the influence of Murdoch and Exxon and the venal think tanks they support can receive its proper welcome.
     

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