Discussion > An experimental demo of GHE.
Radiation from the sun warms the earth.
(In the steady state model, once things have reached equilibrium, there is no further warming. The Earth then stays at the temperature required for equilibrium.)
Martin A
I took another look at the Miatello report. Miatello is clearly a member of the Skydragon community and therefore cannot be taken seriously in any way whatever.
He cites Claes Johnson*. I commented on Claes Johnon's contribution to Slaying the Skydragon in an Amazon review. What he wrote there is not just wrong - it is gobbledegook to the power of tosh.
______________________________________________________________________________
*Claes Johnson's pronouncements on radiation make possibly less sense than the words of Professor Stanley Unwin.
Martin A
Martin A
I am really enjoying the discussion but at the moment I can not get my head round "your theory" ^.^
In your post on the previous page you state this:
The greenhouse effect is where the average temperature of the surface of a planet or moon is, as a result of the presence of an atmosphere containing gases that absorb and emit infrared radiation, higher than it would have been in the absence of such an atmosphere.
Dec 31, 2012 at 5:47 PM | Registered CommenterMartin A
but on this page you state:
Radiation from the sun warms the earth.
So in what way does the atmosphere make the earth warmer?
With or without greenhouse gases, the sun warms the earth, how does it get warmer with the GHE?
Dung
Dung - I need to take time to set it out step by step so it can be followed (or refuted if wrong). Here's a quick stab -let's see if it makes sense....
Essentially, the Sun warms the black body representing the Earth (and surrounded by a thin shell of atmosphere transparent to incoming radiation but intercepting and re-reradiating outgoing radiation in all directions).
Initially the BB is below equiilibrium temperature. The power of the incoming radiation reaching the BB is greater than the power of the net outgoing radiation from the BB, so the BB warms (= its temperature increases). Where does the energy to warm it come from? From the incoming solar radiation. (Net outgoing radiation = radiation emitted by the BB - radiation returning to the BB from the atmos shell.)
The Sun continues to warm the BB until equilibrium temperature is reached. At equilibrium temperature, there is no further warming.
At equilbrium temperature, the power of the incoming radiation from the sun reaching the BB = the power of the net radiation leaving the BB.
The net radiation leaving the BB = the radiation from the black body less radiation returning from the atmos shell. The latter (it seems to me) is simply radiation (or energy, if you like) that the BB did not succeed in getting rid of first go, so has to be re-radiated. That energy left the BB but then returned a few µseconds later so, on its return, there is no change in temp of the BB. Hence no need to argue about backradiation warming things.
Because the radiation from the BB (with the atmos shell) has to be bigger than if the shell were not there (to get the net radiation to balance the incoming from the Sun), its temp has to be higher for it to be in equilib.
Did that make any sense?
[on a quick re-read, I thin it makes ense but does not read too well. Later...]
Martin A
Martin A
(and surrounded by a thin shell of atmosphere transparent to incoming radiation but intercepting and re-reradiating outgoing radiation in all directions)
So incoming radiation doesn't contain radiation of the same wavelength as the outgoing spectrum - are you sure? Or does an atom of greenhouse gas know which direction the radiation is going?
Thanks
Sandy
SandyS
Martin A
Just some observations
During the day cloud reflects a large part of incoming IR from the sun and is cooling the surface.
At night cloud warms the surface by reflecting back radiation that would otherwise be lost to space.
During the day with no cloud and summer sun the surface gets extremely warm, the difference made by cloud is massive.
At night in winter with no cloud it can be extremely cold, the difference made by cloud is massive.
To me this proves that radiation reflected by cloud can indeed warm the surface and that this effect is infinitely greater than any atmospheric effect (if indeed there is one)
It can also cool the surface by reflecting IR from the sun and again this effect dwarfs whatever the atmospheric effect is (if there is one)
Dung
Jan 1, 2013 at 12:21 PM | Martin A>>>>>
Happy new year Martin.
Your obsession with 'dragon slayers' is in danger of becoming a bit like Richard Drakes persistent obsession with 'nyms'. For myself I'm drawn to the empirically based UTC theory of Nikolov and Zeller who, according to a recent email from Karl Zeller, are working on submitting papers for peer review.
Their current PDF is available at :-
http://www.wcrp-climate.org/conference2011/posters/C7/C7_Nikolov_M15A.pdf
Just a couple of questions to keep the discussion going. Both absolutely pertinent to your contributions to this thread and ways in which to discuss them.
Do you agree with the MEASURED Lunar temperature of 197K as MEASURED by the NASA Lunar Diviner probe, and if not could you explain why please?
What contribution in terms of global temperature does the atmosphere make in deg K, relative to an atmosphere less Earth, and why?
Regards,
RKS
OK, clouds reflecting radiation. Just a little problem seeing it quite that way, but maybe it is my lack of education. Clouds are things with a temperature. They radiate on their own, don't they? So without any reflection there is a net flow of energy from surface to cloud which is less than from earth to space, as it would be in the clear sky case. Now, who has measured the reflected vs the 'native' radiation. Should be in different wavelengths, and easy to tell. But I don't believe I am warmer at night with clouds purely because of radiation. Not an intentionally awkward question, just trying to get a handle on it.
rhoda
So incoming radiation doesn't contain radiation of the same wavelength as the outgoing spectrum - are you sure? Or does an atom of greenhouse gas know which direction the radiation is going?Thanks
Sandy
Jan 1, 2013 at 2:29 PM SandyS
SandyS - Yes I'm sure there is essentially no overlap between the spectrum of the incoming and the outgoing radiation.
Most of the incoming power from the Sun lies in the wavelenghts 0.2 µm - 4 µm. About half the power is in the visible range. Water vapour and CO2 are pretty well totally transparent over this range. The Sun's surface temp is around 6000°K, accounting for the wavelengths of the incoming radiation being in this range.
Outgoing longwave IR from the Earth is in the range 4µm - 100µm, due the the Earth's temp being around 255 °K. Wavelengths in this range interact with the greenhouse gases.
Or does an atom of greenhouse gas know which direction the radiation is going?
Greenhouse gases have molecules, rather than atoms acting independently. I don't think the individual molecules of a greenhouse gas have any understanding of the concept of "direction".
Martin A
Well done Rhoda! You are helping expose a profound weakness in the case of those who say rising CO2 levels are going to cause a crisis via a so-called greenhouse effect and a mysterious positive feedback that has appeared in GCMs where it is generally explained as being a consequence of keeping relative hunidity constant and forcing specific humidity to rise as temperatures rise. I mentioned your interest in experimental/observation tests in a comment last year (http://www.bishop-hill.net/blog/2012/12/2/quantifying-uncertainties-in-climate-science.html?currentPage=5#comments Dec 13 11:16AM). Here is the relevant part:
"The real atmosphere works differently, The radiation budget at the ‘top’ of the real atmosphere is a result, an effect, of a spherical planet having very intense incoming solar heating per unit area at the tropical and subtropical surfaces, plus atmospheric and ocean flows transferring heat polewards. The curvature of the earth means relatively modest incoming heat per unit area from the sun as the poles are approached. This results in more heat in than out at low latitudes and more heat out than in at high ones These 'top of the atmosphere' differences in radiation budgets do not drive anything, they are not forces, not 'causes' so much as 'effects'. .
The programmers turn this around, inserting an instantaneous change in this budget as a cause, a driver of, inter alia, temperature changes below it. As I understand it, they install the change (instantaneously at the top of their model atmosphere) and wait and watch (the models do seem to need to be watched because they can go on excursions to produce unacceptable results) while their atmospheres re-adjust ti the disturbance. This is what I mean by the back-to-front nature of this device, and it is not clear to me that it should work. Especially for CO2 changes, which generally begin at the surface in relatively very high concentrations that vary continuously (not instantaneously) in both time and space, and which take a while (at least weeks) to be dispersed and mixed-in, a period in which their contribution is ignored by the GCM modelers.
Now to model that more directly would, I presume, be out of our current grasp on the global scale. But I wonder (as I think does Rhoda who posts comments on this blog) if such a detailed model could be done on a local or regional scale in such a way that testable hypotheses could be produced that observations could confirm or refute. The effect of CO2 is so small compared to other factors in the system (esp. water in all its phases and the changing of these phases, and surface heat driving convective and advective flows) that this might be too much for both our observational and our computational abilities at this stage, but given the colossal sums of money at stake thanks to the political success of the campaigns by people alarmed by CO2 , it seems to me as a somewhat naïve observer that some considerable effort in this area would be highly desirable. Campaigners, though, tell us that the science is settled, and they have been widely believed."
If all the GCMs do this, then they cannot be used to test greenhouse effects since they have presumed their ultimate consequence as an input (a 'forcing'). They are more by way of illustrating what might happen if this version of greenhouse 'forcing' is at least loosely linkable to the real climate system. Missing hotspots, positive bias in temperatures, and generally laughable predictive skill -especially at regional scales (i.e. where everyone actually lives as opposed to the abstract notion of a global climate and the associated global mean temperature) are all seriously discouraging for anyone wanting to bet the farm on GCMs.
But I think there may yet be scope for finding something crucial and testable in computer models, especially any that can begin to model CO2 released at the surface in relative high concentrations and subsequently mixed-in as it rises in a turbulent atmosphere.
John Shade
Jan 1, 2013 at 5:33 PM RKS
Happy New Year to you too, RKS.
Your obsession with 'dragon slayers' is in danger of becoming a bit like Richard Drakes persistent obsession with 'nyms'.
I don't think I have an obsession about the 'dragon slayers'. But I have noticed that their writings contain stuff that directly contradicts the physics as presented in standard textbooks and as used by physical scientists and engineers. And some of their stuff (Claes Johnson) is not merely wrong - it is outright gobbledegook.
So when someone quotes the Dragon Slayers as saying the analysis of the simple black body model surrounded by a shell involves things that are physically impossible, I point out that the simple model can be analysed using straightforward ordinary physics and the Dragon Slayers are known for their wrong explanations of radiation and so on.
Do you agree with the MEASURED Lunar temperature of 197K as MEASURED by the NASA Lunar Diviner probe, and if not could you explain why please?
I don't know anything about that. If they measured it, why should one doubt their measurement? They know what they are doing in the field of remote sensing.
Although one single value seems odd, since lunar surface temperature fluctuates greatly.
What contribution in terms of global temperature does the atmosphere make in deg K, relative to an atmosphere less Earth, and why?
Beats me.
None of what I have posted here applies to the real climate of the Earth. I've said several times that I'm discussing only a simple model of a black body surrounded by a shell of greenhouse gas - a model that has been widely analysed and presented as having some sort of relevance. I've said that, so far as I can see, such a model omits numerous significant effects and makes gross oversimplifications. Therefore, at best, it can be regarded as a plausibility argument that the GHE is significant.
The figure of 33°C is widely quoted and I think comes from this model. It seems simply laughable to me to regard this figure as having any meaningful accuracy.
Martin A
In line with the original question posed by Rhoda, I still can not understand why a simple experiment can not be conducted which proves or disproves the contribution of any greenhouse gas?
Modelling the atmosphere even regionally is a tall order but examining one greenhouse gas to see if it does what it says on the tin can not be beyond us surely?
Dung
Do you agree with the MEASURED Lunar temperature of 197K as MEASURED by the NASA Lunar Diviner probe, and if not could you explain why please?
I don't know anything about that. If they measured it, why should one doubt their measurement? They know what they are doing in the field of remote sensing.
Although one single value seems odd, since lunar surface temperature fluctuates greatly.
What contribution in terms of global temperature does the atmosphere make in deg K, relative to an atmosphere less Earth, and why?
Beats me.....
Jan 1, 2013 at 7:18 PM | Martin A>>>>>
If the Moon, made of the same material as Earth, has a MEAN surface temperature of 197K then the Earth, at the same distance from the Sun and with the same insolation, will also have an atmosphere less MEAN temperature the same as the Moon ie. 197K NOT as you quote from the THEORETICALLY DERIVED warmist science 255K.
Which, of course, means the atmosphere does in fact contribute a much larger 91K to global temperature, rather than the 33K claimed by AGW Hypothesis.
Odd how you use IPCC figures in your own posts:-
"Outgoing longwave IR from the Earth is in the range 4µm - 100µm, due the the Earth's temp being around 255 °K. Wavelengths in this range interact with the greenhouse gases.....
Jan 1, 2013 at 6:19 PM | Martin A"
Yet argue with the rest of their science [other than 'back radiation].
I asked you what made the difference in temperature between an atmosphere less Earth and the present 288K MEAN with atmosphere and you say "Beats me", yet argue in favour of the IPCC 'back radiation'
If 'back radiation' does not contribute to global temperature then discussing it in that context is completely pointless - if you think it does then please explain HOW and, most importantly, BY HOW MUCH - and if not 91K then what, other than the combination of atmospheric pressure and insolation, is responsible for such a large temperature rise.
Don't forget how stars form by atmospheric pressure combined with the 2.7K background cosmic temperature.
RKS
Martin A
As I recall after 45 years, the radiation from the sun at the edge of earth's atmosphere is pretty much like that from a black body at 6000'K at about 1360 W m-2. A bit of research shows that roughly 4% lies at longer wavelengths than 2500 nm (2.5 um?) so about 50W m-2 incoming is in the long wavelength "tail" and this must overlap the earth's outgoing radiation to some degree. Now the question is is there more incoming at the crucial wavelengths than out going? I don't know if you've answered that already, but browsing through the posts here to check will have to wait until tomorrow.
Thanks
Sandy
SandyS
Martin A
I suspect you have far more questions to answer than time permits ^.^
However when you get the chance:
You said:
Most of the incoming power from the Sun lies in the wavelenghts 0.2 µm - 4 µm. About half the power is in the visible range. Water vapour and CO2 are pretty well totally transparent over this range.
but that is not true. Water in the form of clouds strongly reflects IR from the sun....albedo effect. It also reflects IR from the ground.
Dung
Martin A
Curiosity got the better of me, these quotes from you indicate that you might be playing devil's advocate?
Beats me.
None of what I have posted here applies to the real climate of the Earth.
The figure of 33°C is widely quoted and I think comes from this model. It seems simply laughable to me to regard this figure as having any meaningful accuracy.
SandyS
Martin A
Curiosity got the better of me, these quotes from you indicate that you might be playing devil's advocate?
(...)
Jan 1, 2013 at 9:35 PM SandyS
SandyS.
I'm simply putting down what I understand. When I don't know, I say so. I'm certainly not putting down anything I think to be incorrect.
I was not intending to provoke a debate - I was originally trying to answer some questions Dung had posed.
Martin A
Martin A -
Essentially, the Sun warms the black body representing the Earth (and surrounded by a thin shell of atmosphere transparent to incoming radiation but intercepting and re-reradiating outgoing radiation in all directions).
Sorry, I cannot accept that the atmosphere is transparent to incoming radiation. Here at 56 degrees north, from November through to February, even on the clearest (and windless) days without a cloud in the sky, the Sun rays have virtually no warmth (even when you angle your skin to be perpendicular to the Sun, so you should be receiving the same Watts/m2 as someone sleeping by a pool in the tropics). This is not because the days are shorter, but because even at midday the Sun is lower in the sky and the corresponding route the photons take through the atmosphere to get to the surface is much longer. Hence, a significant amount of the incoming radiation is being absorbed by the atmosphere, and I very much doubt that particulates are the guilty few. I remember this from an 'O' Grade geography lesson (my physics teacher would not have covered this subject because it was so obvious). A Spanish friend was not so well informed; the first time she visited Mrs Lapogus' family in Edinburgh, and saw the bright sunshine on a February morning, she went up town in some thin clothes, thinking the sun would soon warm her up as it did on the very cold winter mornings in her native Granada. She was back within minutes asking for a thick jacket, genuinely puzzled as to why the Sun was not warm in Scotland.
lapogus
Hi Dung,
I said:
Water vapour and CO2 are pretty well totally transparent over this range.
You said
but that is not true. Water in the form of clouds strongly reflects IR from the sun....albedo effect. It also reflects IR from the ground.
I think you are seeing a disagreement between us where there is none.
Clouds are droplets of liquid water or particles of ice, so their properties are quite different from water vapour, which is a gas.
Clouds are one of the many aspects neglected by the simple model (BB surrounded by GG shell), which is why claiming it shows precisely 33°C attributable to GHE seems silly to me.
Martin A
Jan 1, 2013 at 10:08 PM lapogus
Lap - Thanks for the comment. it's a model I've been talikng about, not the real thing. And obvioulsy a very crude approximation to reality.
The red sun at sunset shows that the cloudless atmosphere is not 100% transparent at all wavelenghts at all times.
Martin A
Odd how you use IPCC figures in your own posts:-"Outgoing longwave IR from the Earth is in the range 4µm - 100µm, due the the Earth's temp being around 255 °K. Wavelengths in this range interact with the greenhouse gases.....
Jan 1, 2013 at 6:19 PM | Martin A"
Yet argue with the rest of their science [other than 'back radiation].
I asked you what made the difference in temperature between an atmosphere less Earth and the present 288K MEAN with atmosphere and you say "Beats me", yet argue in favour of the IPCC 'back radiation'
RKS
"Outgoing longwave IR from the Earth is in the range 4µm - 100µm, due the the Earth's temp being around 255 °K.
It's straightforward application of Planck's formula for the spectrum of black body radiation. Is there any reason to seriously doubt it?
I don't think you can have read what I wrote if you think I argue in favour of the IPCC 'back radiation'.
Several times I have made the point that the idea of so-called "back radiation" warming things seems to me to be nonsense made up by people who don't understand basic physics. The fact that the dragon slayers devote much time to debunking it seems odd.
Martin A
just wondering whether anyone else is following the threads here:
http://clivebest.com/blog/
the man has serious credentials as a physicist - compare with anyone in climate science. he seems to be trying to work out what the GHE actually is from first principles.
diogenes
Lapogus
I can not believe you asked that question when the answer is so obvious ^.^
In your neck of the woods in winter; light from the sun is arriving almost at a tangent to the surface. The power of the suns rays have therefore been reflected, destracted and generally totally annoyed by thousands of wind turbines before a very sorry few reach your admirably upright body :)
Dung
RKS - do you have a reference for the average lunar temp. calc you mentioned? I did a quick search and found this but couldn't find it. This seemed the most relevant result that came up:
http://davidappell.blogspot.co.uk/2012/05/re-diviner-result.html?m=1
Apologies if this has been bottomed out earlier in the discussion.
not banned yet
Martin A
OK your explanation includes greenhouse gasses that absorb and emit radiation but you say that the radiation emitted does not warm the earth. What is warming the earth then?