Eli Rabett and RW Wood
UPDATE: Arthur Smith has the answer, just look at the first comment. Having put this baby to bed Eli will wrap it up tomorrow but now anytime someone raises the dread climate change is just N Rays flag, constant readers of Rabett Run can tell them, uh uh. Got that Marky?
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R. W. Wood was probably the greatest American experimental physicist of the last century. He was renowned for his design of simple and penetrating experiments (mostly optical). Although it is rumored that he had a first name, Eli only has heard him referred to as R. W. Wood, even by those who knew him (Eli is old enough that only one generation separates him from an older Wood). Wood was the successor to Henry Rowland at Johns Hopkins and outdid the old master (Rowland perfected the diffraction grating). Wood was an immensely practical scientist, as anyone who has ever heard the N Ray story could tell, perhaps rivaled only by Fermi, who had the huge advantage of being a wonderful theoretician (physicists worship theory and tolerate experiment, everything in physics starts with theoretical models).
So, what brings us here? Among other things that Wood did, was to try and devise a test of whether thermal radiation could be trapped in the atmosphere
From this Wood concluded thatTo test the matter I constructed two enclosures of dead black cardboard, one covered with a glass plate, the other with a plate of rock-salt of equal thickness. The bulb of a thermometer was inserted in each enclosure and the whole packed in cotton, with the exception of the transparent plates which were exposed. When exposed to sunlight the temperature rose gradually to 65 oC, the enclosure covered with the salt plate keeping a little ahead of the other, owing to the fact that it transmitted the longer waves from the sun, which were stopped by the glass. In order to eliminate this action the sunlight was first passed through a glass plate.
There was now scarcely a difference of one degree between the temperatures of the two enclosures. The maximum temperature reached was about 55 oC. From what we know about the distribution of energy in the spectrum of the radiation emitted by a body at 55 o, it is clear that the rock-salt plate is capable of transmitting practically all of it, while the glass plate stops it entirely. This shows us that the loss of temperature of the ground by radiation is very small in comparison to the loss by convection, in other words that we gain very little from the circumstance that the radiation is trapped.
Is it therefore necessary to pay attention to trapped radiation in deducing the temperature of a planet as affected by its atmosphere? The solar rays penetrate the atmosphere, warm the ground which in turn warms the atmosphere by contact and by convection currents. The heat received is thus stored up in the atmosphere, remaining there on account of the very low radiating power of a gas. It seems to me very doubtful if the atmosphere is warmed to any great extent by absorbing the radiation from the ground, even under the most favourable conditions.Eli and others, including the dread Stoat, have thought about this demonstration for a long time and certainly it is a favorite of the denialati, including some of our home grown ones, as an at this time ongoing interchange shows.
Eli had a flash of understanding this afternoon about what RW was measuring and why it is not relevant to the Greenhouse Effect. The hint is that the absorptivity of the glass in the IR is roughly unity as is that of the black cardboard, and therefore their IR emissivity is also unity in the IR by Kirchoff's law. Another hint, if you can understand what is wrong in the bunnies discussion of the Greenhouse Effect, you should have a good idea of what Wood measured and why it did not prove what he thought it did.
Now that the Bunny has ruined your Saturday night, Ms. Rabett is calling:)
Posts
58 comments:
Mr. Rabett:
I think what you mean to say is that R.W. Wood was a deceitful fraud. It's clear that he hid data and fudged the results to meet predetermined ends.
I demand an investigation.
From the other thread,
>The reason for this is that collisional de-excitation is much faster
>(like a few orders of magnitude)than emission so essentially all of
> the CO2 which absorbs an IR photon, losses it in a few microseconds.
I have never been able to find this info. Do you happen to know what these times actually are -- excitation time vs collision time at standard temperature and pressure? thanks.
Sounds like what I worked out over at David Stockwell's "landshape" blog a while ago when he was trying to replicate these experiments. Outgoing radiation is only reduced (and bottom temperature raised) if the glass temperature is *lower* than the bottom. If you had a vacuum, the coupling between glass and bottom would be by radiation only and there should be a good temperature differential. But with a small air gap the two temperatures will stay close, and there will be no substantial "greenhouse" effect.
Interestingly, Stockwell was going on about Miskolczi's theories at the time and how what he was seeing proved the greenhouse warming was limited. I challenged him with a scenario that would see a lot more warming, and he set up something like it, I estimated the temperature he should see, and was pretty close to what he in fact observed. But still he clung to his Miskolczi. Not just physicists who love their theories...
Bob:
It's not one of the more common things to find. The only source I have on hand that gives the collisional relaxation time vs. the radiative relaxation time is Goody's The physics of the stratosphere (1954) (chapter 6). (Probably Spitzer's 'diffuse matter in space', or "physics of the interstellar medium', a generation from each other also discuss such things, but only for more astrophysical contexts.)
Speaking of wood and theoretical models...
She lit a fire in the wood-stove and offered me a pipe
"I thought you'd never say renewable " she said
"You look like the Exxon type"
Then she opened up a book of equations
And handed it to me
Written by a Swedish chemist
From the nineteenth century
And every one of them numbers rang true
And glowed like burning coal
Pouring off of every page
Like it was written in my soul from me to you
Tangled up in CO2
Hey, what happened to the title? You finally had parsed titles in my google page (the one dedicated to all things bunny) but this post has none.
Horatio,
I visited your blog to see the entire set of lyrics.
Clap, clap, clap!
You can teach an old Rabett new tricks, but you have to give him time to practice
Assuming the convective transfer of heat from the bottom of the enclosure to the glass is not 100% efficient, and the glass is slightly colder, the glass enclosure will be radiating fractionally less IR. Is it possible to calculate the temperature difference in the glass enclosure this would make? If so, is it about 1 degree? Has anybody repeated the experiment to see if it was the glass enclosure that was warmer, or if indeed there is a real difference of 1 degree, or if it was an product of slight physical difference in the enclosures used?
Two odd things about this description. First he doesn't say there was no difference; he says scarcely a degree. But more significantly, he seems to say that he had a glass plate above the rock salt. If that's true, then it negates the experiment. The glass would still block IR, warm, and radiate back.
I got into an argument with some Woodies at Lucia's #26531 a while ago. I pointed out that:
Greenhouses are warmed by IR blocking, even if it isn’t the biggest effect. In fact, it’s part of routine parctical greenhouse economics. This pamphlet describes IR-opaque plastic covering materials which, they say, can reduce heating costs by up to 20%. They are on the market, and someone is presumably buying them, though they cost more.
and
Here is an experimental study by cornell horti people of IR blocking coverings for tunnels – long GH-like structures. They said IR blocking made them 1-3F warmer (total warming about 10F).
"But more significantly, he seems to say that he had a glass plate above the rock salt. If that's true, then it negates the experiment. The glass would still block IR, warm, and radiate back."
I suspect he passed the light falling on both enclosures through the same piece of glass so that both were only receiving light in the visible spectrum.
"Greenhouses are warmed by IR blocking, even if it isn’t the biggest effect. In fact, it’s part of routine parctical greenhouse economics. This pamphlet describes IR-opaque plastic covering materials which, they say, can reduce heating costs by up to 20%."
Do these materials absorb IR or reflect it? I'm guessing untreated glass itself absorbs and these films reflect.
No Nick. You mis-understand.
The Rock salt is atop one enclosure to let IR out. A second glass sheet higher up, covers both enclosures, so there is no IR coming in to either.
So the rock salt enclosure allows IR out, but not in. The glass topped enclosure allows no inward or outward IR.
That is why Warmers don't like the experiment.
It shows that black body IR emission has no material effect on temp. Therefor, whatever CO2 does with IR has no effect either.
End of AGW theory.
Where is the cotton, exactly?
MarkeyMouse says:
Well now all Arthur has to do is prove his theory by experiment.
Can't wait.
PS Shouldn't all this have been done before, already?
"The glass topped enclosure allows no inward or outward IR."
The glass emits IR, just like the black cardboard (...their IR emissivity is... unity)- that's the point. If convection heats up the glass to the temperature of the black cardboard, then the glass emits as much IR as the black cardboard, and from an IR transfer point of view, it has as much effect as the rock-salt.
I haven't done the vacuum experiment - I don't need to since the theory is really very simple and straightforward. But feel free to go ahead yourself. The theory worked great when David Stockwell tried some similar experiments here:
http://landshape.org/enm/global-warming-effect-experiment-3/
"The temperature of 119.9 is the peak temperature recorded before an out of range result was recorded. This was high enough to start to melt the EPS foam, as shown below. This surprises me for non-concentrated solar source, but was anticipated by Arthur Smith in a comment here."
The rock wool is around the tube to insulate it, limiting conduction out of the apparatus from the sides and bottom.
If you want to get down to fractions of a degree you have to consider such things as the emissivity as a function of wavelength at the temperatures you are working at. One of the optical holy grails is for a true flat black, e.g. a black materials that is completely absorptive (and thermally emissive) at all wavelengths.
Marky dear, you may not have noticed, but a combine harvester got driven through your haystack last night.
Now you got a choice, dig in, and the bunnies do the roll the eyes bit and you are labeled for life as a useless idiot, or admit that, yeah, that explains Wood's results.
Nick Stokes seems to have forgotten:
MarkR (Comment#26664)
December 7th, 2009 at 12:53 am
Nick Stokes (Comment#26640) Your link to the plastic sheet experiment shows that the IR protection doesn’t have any material effect on the greenhouse in the daytime, so tell me the story again how sunlight (daylight) reaches the Earths surface, and is then changed to IR Radiation and re-emitted, and that stopping the re-emission warms the atmosphere?
Not on the basis of your link it doesn’t. Your link reenforces Woods.
MarkeyMouse quotes Woods:
"...heat energy is re-emitted by the walls in the form of much longer waves, which are unable to penetrate the glass, the greenhouse acting as a radiation trap.", and:
"From what we know about the distribution of energy in the spectrum of the radiation emitted by a body at 55 o, it is clear that the rock-salt plate is capable of transmitting practically all of it, while the glass plate stops it entirely. This shows us that the loss of temperature of the ground by radiation is very small in comparison to the loss by convection, in other words that we gain very little from the circumstance that the radiation is trapped."
http://www.wmconnolley.org.uk/sci/wood_rw.1909.html
Now Arthur says: "Outgoing radiation is only reduced (and bottom temperature raised) if the glass temperature is *lower* than the bottom."
But the point of Wood's experiment is to use glass which is not transparent to IR at the given temperature. In such a case he shows that the IR energy retained in the test compartment is trivial. This still leads to the conclusion that whatever CO2 does with IR, its effects are trivial.
Back to you Wurzels.
You can actually get a reasonable estimate of the temperature difference that should be there just from the numbers for Earth's lapse rate. The dry adiabatic lapse rate is about 10 K per km, as I recall. So for a real greenhouse where there are maybe 3 meters from ground to glass, you would get maybe 0.03 degrees difference between ground and glass temperature, in steady state (of course the fact that the sun moves through the sky also has some impact, so the steady state probably isn't a good approximation in reality). I haven't looked at the dimensions of Woods' experiment, but presumably it was even smaller than that.
But we already knew that glass greenhouses do not share the physical characteristics of the atmospheric greenhouse effect. They are indeed, as Wood showed, dominated by convective constraint. On the other hand, the same underlying change in energy flux is there in both cases - you are reducing convective energy flow from the sunlit ground into the high atmosphere in the glass greenhouse, and reducing radiative energy flow from the ground to the high atmosphere with greenhouse gases. So it's not a bad analogy, but you have to actually understand it, and not just pontificate without physical understanding, as seems to be done far too frequently.
MarkeyMouse says: Arthur, I merely re-stated the terms of the Wood experiment by quoting from him. All of the quotes conflict with your description of your experiment. IR either was blocked by Wood's experiment, or not.
The reach for the "dry adiabatic lapse rate" is a sign of something. Perhaps you could remind me? It was never mentioned in your original post?
"Markey" - IR is blocked by the glass, and it is also re-radiated by the glass. If the glass is at the same temperature as the ground, then the glass blocking IR has *no effect* on net outflow of radiation from the system.
The ground radiates at a flux F, some number of watts per square meter. The glass, if it completely blocks all IR, that means it catches all of F. It then radiates F back to the ground (because it's at the same temperature as the ground and has essentially the same emissivity); assuming the glass is thin enough to be at a uniform temperature, it also radiates F upward to the atmosphere. And of course there are other energy fluxes from ground to glass thanks to the motion of air within the system.
So without the glass, or with a rock-salt cover instead of glass, the net radiation upwards is F. With the glass, the net radiation upwards is F. I.e., the glass, despite "blocking" the IR, has zero net effect. That's what the theory says, and what Woods' experiment proved. IR is not relevant for a glass greenhouse filled with air, simply because convection completely overwhelms radiation on that short length scale.
Rather than a vacuum, another experiment is to use a thick enough piece of glass (or many layers of glass, as Stockwell tried) so that there is a temperature differential within the glass itself. The conductivity of glass is sufficiently low you probably don't have to get too thick. Of course you need to factor in whether or not some of that extra glass is blocking incoming sunlight as well - best to have the clearest possible material in the visible for this experiment. Anyway, that would allow the top layer of the glass, which radiates upward, to be at a lower temperature than the bottom layer, which is fixed at pretty much the same temperature as the ground layer. Then you would have a real IR greenhouse effect.
Hey Markey, when you were quote mining, you missed this one from Wood's original note:
"I do not pretent to have gone very deeply into the matter,..."
Wood acknowledges that his experiment might not be the last word. And it isn't.
So if the glass gets F by radiation, and radiates 2F, it must get F by convention as well (F+F=2F). An interesting result, though I might be mistaken here. Also the cardboard is getting 2F (one F from the heater and one F from the glass) and radiates F and convects F?
In a radiation dominated case (no convection), the glass would radiate half back so the system would equilibriate to 2F radiated from the cardboard, 2F absorbed by the glass, F radiated back and F out. Cardboard would receive F from the lamp and F from the glass.
Since the glass is double sided, but radiates the same as the cardboard, it has a cooler temperature. Some 20 percent difference?
Or in other words, the cardboard is 20% hotter in Kelvins than in the convection case.
Arthur said:
"It then radiates F back to the ground (because it's at the same temperature as the ground and has essentially the same emissivity); assuming the glass is thin enough to be at a uniform temperature, it also radiates F upward to the atmosphere."
So the Glass receives F from below and reflects it back at a cooler frequency, and also radiates F upwards?
Where can I find this glass that receives 1 F and gives 2 F in return?
Something has not been thought through here.
In your window. The glass also receives thermal energy from the surroundings as well as the bottom of the cell. If the glass is thick a thermal gradient will appear, and there will be more back radiation than forward radiation, which was Arthur's point.
Isn't all of this chatter just confirming that you have to include an accurate representation of clouds in any theoretical model if you want to replicate the "greenhouse effect"?
Anonymous said "Where can I find this glass that receives 1 F and gives 2 F in return?" - but Flavius Collium had it right in the comment just above: "if the glass gets F by radiation, and radiates 2F, it must get F by convention as well (F+F=2F)." As was also implied when in my original comment I said "of course there are other energy fluxes from ground to glass thanks to the motion of air within the system."
I think our anonymous commenters should learn to read a little more carefully, before making a fool of themselves commenting.
MarkeyMouse says: Arthur, you did say "The ground radiates at a flux F,.. The glass, catches all of F. It then radiates F back to the ground ...., it also radiates F upward to the atmosphere."
Sorry Arthur. The Glass can't create energy, it may recieve in F and tranfer out F, but it can't transfer out 2F. Can it?
In any case, I think if you are confident you have a sound theory, you should seek to publish it in a Journal where it will be subject to peer review.
I'm sure with a discovery of this magnitude, the IPCC will be all ears. Beats me how they hadn't covered it before.
Thick piece of glass is a quite clever way to manufacture a lapse rate, though I still doubt it'll work well. What did this stockwell observe?
Kent: The physics of clouds I don't are required for a simple model that produces a lapse rate. Just thermo, gravity, and if you want water, then Clausius-Clapeyron to make sure it condenses when it's supposed to. The characteristics of the resulting cloud don't matter so much for this purpose. At least that's how imagine it; I never wrote a model about it.
"Markey" - the issue has been explained at least 3 times to you here and yet you persist. I thought deliberate trolls were more intelligent than that - perhaps your evident incomprehension is rather a sign of innocent ignorance.
Energy is conserved in the glass through the convective heat flow, the "motion of air" I mentioned earlier, which I referred to twice previously and another commenter also explained. It is only when you remove convective heat flow (for example under vacuum conditions) that you can consider only radiation.
The net flow of infrared radiation out of the glass in the case with air is balanced by a net inflow of convective heat via the air to the glass. Take away the air, and the net radiative flow causes the glass to cool down, in turn radiating less energy out of the system, and causing the ground to heat up. That give you infrared greenhouse under vacuum, and essentially no infrared greenhouse with air over such a short distance.
This hardly needs some complex theory or discussion - the math is essentially 1+1=2, as long as you include all the physical factors.
If you read Wood's actual paper, he did his experiment to look into the importance of radiation vs. convection for a regular greenhouse. His result was absolutely correct for that. He also included a completely wrong statement that "It seems to me very doubtful if the atmosphere is warmed to any great extent by absorbing the radiation from the ground". Satellite measurements prove quite conclusively that the atmosphere has "high radiating power" over a range of relevant wavelengths.
So you really want to hang your hat on a provably wrong side-note in a 1909 paper?
This is maybe a good time for a lazy question.
Considering the cartoon here,
http://www.windows.ucar.edu/earth/Atmosphere/images/earth_rad_budget_kiehl_trenberth_1997_big.gif
Is net convection between surface and lower atmosphere really limited to that little flow called 'thermals'?
At some level, the cartoon needs to have more slabs in the atmosphere.
Arthur, MarkeyMouse is either being deliberately obtuse or is incapable of understanding what you are telling him. Don't let that dishearten you. For those of us who know enough science to grasp what you are saying, your efforts are greatly appreciated.
MarkeyMouse says:
Doesn't what the Wood experiment show, and you and Rabett confirm, that IR radiation leaving a black body is absorbed by either Water Vapour or CO2, almost instantaneously, certainly below the level of Wood's Glass sheet,and then convected to the glass sheet where it is conducted outwards.
In other words, more or less CO2 doesn't matter. The Photons are already absorbed very close to the surface. It is Convection that takes it onwards.
As I said, end of AGW CO2 theory.
How can somebody be so utterly incoherent, and yet so sure of himself?
"Markey" - you're off on yet another tangent now. Do you actually have a single coherent argument you will stick to? It doesn't sound like it.
Anyway, no, Wood's experiment would work fine with absolutely no CO2, H2O, or anything absorbing IR. Perhaps what you're not understanding is that heat energy is transported by several physically distinct and completely independent means, each of them working in parallel. If you've ever worked with electrical circuits, you understand what that means - transport is dominated by the components with the largest transport rates. What those are depends on the details of the physical system:
(1) Conduction: collisions between molecules or atoms (or electrons/ions) that transfer energy, on average moving heat from hotter to colder places. For gases this is not a fast heat transport mechanism; heat conduction is much more significant in solid materials that cannot support convection.
(2) Convection: motions of local pockets of material between regions of different temperature. Equilibration through mixing and conduction after transport results in net heat flow from hot to cold. Physically moving the hot stuff to where the cold stuff is can transport a lot of net heat very quickly, so if convection is possible in the physical system it tends to be a large effect. (Rabett's fur keeps him warm by blocking convection)
(3) Latent heat: like convection, but associated with a phase change (like from liquid water to water vapor) which allows even larger quantities of heat to be transported quickly, if latent heat transport is possible. We sweat to cool off quickly through the phase change energy associated with water evaporation.
(4) Radiation: I think we've covered this enough, what I think Eli's been trying to get people to understand is the importance of both sides of the radiative flow - outgoing and incoming. Outgoing radiation can be quite large, but if it's canceled out by incoming radiation from bodies at the same temperature (as in Wood's glass cover case) then the radiative flow is not important for that particular physical system.
In any given case you need to understand the numbers for all the different physical processes, to see which ones are more important. That's what the Kiehl-Trenberth diagram does quite nicely for the atmosphere.
Markey said: "end of AGW CO2 theory."
There is no "AGW CO2 theory" Markey, you are tilting at a windmill. AGW is only a variation of the greenhouse theory. The only thing anthropogenic is how the extra CO2 is getting into the atmosphere. It's the greenhouse theory itself that you are in denial of.
Carrot Eater, being incoherent and sure of himself are features with Marky that are not in conflict. However Arthur is handling this right.
MarkeyMouse says: ""There is no "AGW CO2 theory"" Phew, that's OK then. The AGW Greenhouse Theory ignores the reality that CO2 levels have been as high as 7000 ppm versus todays lower level, but there has never been a correlation between CO2 and atmospheric temp, and there isn't now. Seemples.
You mustn't rely on Trenberth, "..but the data are surely wrong. Our observing system is inadequate." He prefers phantasy to reality.
Talking of reality. Did you see this:
"My son and I repeated the experiment as mentioned and we the same results. We then used two glass jars, one as a control and one with water vapor and got the same results. We tried the two jar experiment again, but his time we stayed indoors and used a heat lamp and got the same results. In our fourth experiment we use one jar as a control and added vinegar and baking soda to the second jar to produce CO2. After and hour into the experiment we added even more vinegar and backing soda to create even more CO2 and yet again the temperature did not increase. The mean control jar temperature was 34.87 while the experimental jar was 35.43. The mean humidity for the control was <20% (we could not measure below 20%) and the mean humidity of the experimental jar was 42.73%."
http://landshape.org/enm/simple-multi-layer-greenhouse/
See. Adding CO2 doesn't make any difference.
"Doesn't what the Wood experiment show, and you and Rabett confirm, that IR radiation leaving a black body is absorbed by either Water Vapour or CO2, almost instantaneously, certainly below the level of Wood's Glass sheet,and then convected to the glass sheet where it is conducted outwards."
No.
Wood's experiment was quite literally a black box experiment. Trapping IR in the box had no effect.
The experiment didn't investigate what happened inside the box.
A century later and some other people are theorising about why trapping IR had no effect.
The perfectly plausible explanation as mentioned before is that the glass plate emitted an amount equal to the amount it trapped as it warmed through convection. (If I have that right.)
The simple explanation for the convection is direct contact between the air in the box and the hot bottom of the box. (No disrespect to Arthur's longer and more technical answer.)
I have no idea how much IR would be absorbed by CO2 and water vapour over 50cm or so, but I'd suggest it would be a negligible amount. I would also suspect that R. W. Wood, as a physicist, would have known that for sure, and not used a glass plate to trap IR if the IR radiation could not have reached the height of the glass.
There's certainly nothing in this experiment to support your contention; a lot to suggest that either Wood wasn't "the greatest American experimental physicist of the last century", or your theory is baseless.
"As I said, end of AGW CO2 theory."
Wood's glassed-topped black cardboard enclosure experiment is a very good analogy for a garden cold frame. Anything else is pushing it a bit.
MarkeyMouse says: Donald. The IPCC say that "Greenhouse gases and aerosols affect climate by altering incoming solar radiation and outgoing infrared (thermal) radiation that are part of Earth’s energy balance." http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf
Or, IR reflected from the Earths surface is intercepted by CO2 and traps heat.
Wood's experiment shows that trapping reflected IR doesn't produce heat in any circumstances, and therefor CO2 trapping it is irrelevent.
Secondly, the amateur experiment referred to above, showed that adding Water Vapour or CO2 doesn't trap heat.
What part of this is not understandable?
Donald. Sorry I missed your key point, "The perfectly plausible explanation as mentioned before is that the glass plate emitted an amount equal to the amount it trapped as it warmed through convection".
Exactly. So in the real world the IR is transferred to Convection and transmitted upwards. It is not "trapped" anywhere.
This is exactly where AGW theory goes wrong, as expressed here: "Carbon dioxide from fossil fuel burning and land clearing has been accumulating in the atmosphere, where it acts like a blanket keeping Earth warm and heating up the surface, ocean, and atmosphere." http://www.ucsusa.org/global_warming/science_and_impacts/science/global-warming-human.html
They go on to say: "This has led to the troposphere warming more because the increase in heat-trapping emissions is trapping more of Earth's outgoing heat."
But the troposphere has not been warming, apparently.
See. End of AGW CO2 theory.
What you have said, and Rabett, and Arthur, have all inadvertantly re-enforced thet view.
The trouble is, the IPCC don't really give any proper description of how AGW CO2 worls on a molecular level. (they can't, because it doesn't), but the corollary is that as soon as the Warmers try a detailed explanation, it all goes tits up. (Can I say that here?)
"Wood's experiment shows that trapping reflected IR doesn't produce heat in any circumstances, and therefor CO2 trapping it is irrelevent.
What part of this is not understandable?"
It shows this in what is basically a garden cold frame- and there's a perfectly sensible theoretical explanation why.
The atmosphere is about 50,000 times taller, divided into layers where different things happen, has heat transfer by convection, evaporation and condensation, and radiation. Radiation is absorbed and re-radiated by gasses at different pressures and relative concentrations upwards through the atmosphere, and absorption bands change.
What I find not understandable is how a garden cold frame is analogous to the atmosphere.
Measurements and calculations from the 50's showed that theoretically, adding more CO2 should cause warming. Now we have satellite measurements that show IR leaving the atmosphere has dropped just where CO2 absorbs it, and measurements from the earth that show IR radiation back to the earth, just where CO2 absorbs it.
So we have theoretical and observational evidence to confirm that there is no analogy, even if you were tempted to see the atmosphere as a single layer warmed by convection topped with a sheet of glass.
Look at the atmosphere as a black box: IR leaving at the top is dropping. The atmosphere must warm as a result. There is no comparison.
"Exactly. So in the real world the IR is transferred to Convection and transmitted upwards. It is not "trapped" anywhere."
In the real world, convection only transfers a fraction of the heat, and only part of the way up the atmosphere.
http://www.windows.ucar.edu/earth/Atmosphere/images/earth_rad_budget_kiehl_trenberth_1997_big.gif
And the atmosphere is not topped with a layer of glass.
"But the troposphere has not been warming, apparently."
Your source was right: it is warming.
MarkeyMouse says: You guys really are amazing.
Donald says re Troposphere: "Your source was right: it is warming."
Real Climate say: "It turns out that the upper-air records have not shown the warming that should accompany the reported increases at the surface. Both the Microwave Sounding Unit (MSU) satellite (analyzed by the University of Alabama in Huntsville by John Christy and Roy Spencer) and weather balloon data (trends reported by a number of researchers, notably Jim Angell at NOAA) have failed to show significant warming since the satellite record began in late 1978, even though the surface record has been rising at its fastest pace (~0.15 C/decade) since instrumental records began."
But go on to say: "The most likely resolution of the “lapse-rate conundrum,” in my view anyway, is that both upper-air records gave the wrong result......"
http://www.realclimate.org/index.php/archives/2005/08/the-tropical-lapse-rate-quandary/
See. Wheneve data and theory conflict, the Warmers say the data is wrong.
They are in denial.
Aside from the criminal adjustments by CRU, global surface temperatures have not risen, even the Russians say the books have been cooked.
The Arctic ice area is expanding from a recent low point.
The upper Troposphere is not warming.
No. Hurricanes aren't increasing.
No. Glaciers aren't retreating at unusual pace.
No. Polar Bears aren't facing exctinction.
No. The latest Climategate email wasn't 10 years ago. (per Al Gore)
No. Sea levels aren't rising.
At what point will you accept that when the facts change, your opinion must change?
Your link is from August 2005.
An error was found in the satellite data in November 2005. When the error was corrected, the satellites showed warming for the troposphere.
http://www.skepticalscience.com/satellite-measurements-warming-troposphere.htm
Science moves on.
Your other points are off topic.
MarkeyMouse says: Donald says "When the error was corrected.."
They've had several attempts, the last one boiling down to averaging the differences and then adjusting the Sat record.
“This paper introduces a new technique that uses time series of temperature differences between the original radiosonde observations (obs) and background forecasts (bg) of an atmospheric climate data assimilation system for homogenization.”
All fully picked over here:
http://climateaudit.org/2008/05/01/david-douglass-comments/
What you have is the standard operating procedure for the ClimateGate Group.
Invent and model a theory (upper tropospheric warming)
Models don't match data.
Alter the data to fit Model.
When someone gets an opposing paper published, (or even while it's in press cos your mates tipped you off) get someone to hack a counter and bully compliant and uncritical Journal to publish.
Same formula as CRU, and wrong wrong wrong.
"Markey" once again is heading off on tangents and cannot stick to a single claim that makes any coherent sense. He appears not to have absorbed or understood anything that's been said on this thread. That definitely does sound trollish, although a particularly stupid one.
In any case, the central point in scientific analysis of a physical system is to understand the parts of it that are important - those things that are quantitatively large or affect its behavior measurably, and those which are smaller effects. If you want to do an experiment that tells you something about a physical system of some sort, your physical system must be a good analog - the things that are quantitatively large in the experimental analog must also be quantitatively large in the physical system you are trying to learn about, and what's small in one must be small in the other as well.
Wood's experimental setup, and the similar ones discussed on the "landshape" blog, are good physical analogs of a cold-frame as D. points out just above, and not too bad as analogs of a real glass greenhouse. But they are very poor physical analogs of the full atmosphere, because they are unable to support the large temperature differential needed to see an infrared warming effect.
Boiling it down -
Atmosphere: large temperature difference (70 degrees C or more) between ground and tropopause
Wood-style experiment: essentially no temperature difference between ground and glass.
Therefore the Wood experiment is not a good analog of the atmosphere for this purpose, and you can conclude nothing about the effects of CO2 on the atmosphere from doing Wood-style experiments - unless you fix that issue of the substantial quantitative difference between the systems, and I've mentioned two ways that could easily be done.
Go ahead and try those experiments yourself if you like.
good lord. The need for the correction to the satellite record was fully acknowledged and accepted by the sceptics who publish the satellite record - the same two sceptics who were previously proudly telling anybody who'd listen that their satellite records showed no global warming.
You're really good at illogically flitting from topic to topic, instead of actually thinking about the one on hand.
Markey's divorce from reality appears to be near total.
I see no point in further indulging his flights of fantasy.
MarkeyMouse says: Arthur just moved the goalpost again, "large temperature differential needed to see an infrared warming effect." The IPCC doesn't say anything about that. (Do you have a reference?). They say it's the special ability of CO2 to cut off IR escape from atmosphere that causes AGW.
Wood's experiment and the other experiment referred to above shows you can have as much CO2 and H2O Vapour as you like, and the sample atmosphere doesn't warm.
Re OT Satellite stuff, it was one of the other posters who introduced it. Have a go at him.
"Markey" - moved the goalpost? In my *very first comment on this post* I mentioned that the critical thing was the temperature differential:
"Outgoing radiation is only reduced (and bottom temperature raised) if the glass temperature is *lower* than the bottom."
And I have repeated this issue at least 4 times since then. Perhaps that's how many times you have to hear the same thing rephrased different ways before it starts to sink in.
As to the IPCC saying it is "the special ability of CO2 to cut off IR escape from atmosphere that causes AGW." - you just made that up off the top of your head, didn't you? Have you actually read the IPCC reports, at all? The relevant section in AR4 WG1 is Chapter 2, the start of section 2.2 puts it:
"The definition of RF from the TAR and earlier IPCC assessment reports is retained. Ramaswamy et al. (2001) define it as ‘the change in net (down minus up) irradiance (solar plus longwave; in W m–2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values’"
I.e. it depends on the concentration of GHG's and *on the temperatures of the surface, troposphere, and stratosphere*. If you don't match that temperature profile, then you don't get the same radiative forcing. The temperature profile is critical, and stated right there, up front.
"Markey" - learn to read, and stop just making stuff up.
MarkeyMouse says: Arthur says "large temperature difference (70 degrees C or more) between ground and tropopause" and "Outgoing radiation is only reduced (and bottom temperature raised) if the glass temperature is *lower* than the bottom." are the same thing. I don't think so. Also you provided no IPCC ref.
And I think you're getting mixed up between what the IPCC say about how CO2 effects Warming by intercepting IR, and how the IPCC measure RF. Two different things.
"Markey" - there needs to be a temperature difference. 70 C is the scale it is in the atmosphere but if there's no measurable difference in your experimental system, then your system is simply not testing the relevant question. No, I didn't say exactly the same thing over and over, I rephrase to try to explain. My phrasing is not that of the IPCC, but the meaning, again is clearly the same.
And "Markey" - the reason anything causes warming is because it causes the atmosphere to retain more energy than it otherwise would - this is called "radiative forcing", abbreviated "RF" in the IPCC section I referenced. Try reading it - just google IPCC AR4 WG1, download chapter 2, and start. It's really not that hard.
“There appears to be a widespread belief that the comparatively high temperature produced within a closed space covered with glass, and exposed to solar radiation, results from a transformation of wave-length, that is, that the heat waves from the sun, which are able to penetrate the glass, fall upon the walls of the enclosure and raise its temperature: the heat energy is re-emitted by the walls in the form of much longer waves, which are unable to penetrate the glass, the greenhouse acting as a radiation trap”
If glass greenhouse heating resulted from a transformation of wavelength, and nothing else, the following would be true:
Incoming radiation is W per square meter, so the outgoing radiation must also be W per square meter.
But the glass radiates up as well as down, so the radiation from the interior to the glass must be 2W. (Arthur Smith’s 1 + 1 = 2).
So, the interior temperature must increase sufficiently to radiate 2W to the glass.
In the rock-salt greenhouse, with no outgoing radiation absorption, the interior radiates only W.
The ratio of the two interior temperatures (from Stefan-Boltzmann) will then be the fourth root of 2, or 1.19.
This pernicious theory is the original AGW greenhouse theory and can be found in Eli’s rebuttal of the G and T paper (in a 2 layer version, which makes the result, the fourth root of 3, even sillier). It is said to be the reason why the earth surface is 33 degrees C warmer than the moon’s.
But Woods claimed that radiation plays a negligible part in warming a greenhouse. Why not? Arthur Smith says it was because the temperature differential between the interior and the glass was not sufficient. Eli says the glass and the interior are at the same temperature.
But in the world of theoretical Physics we can set the temperatures at any level consistent with the well established convective and radiative heat transfer equations, which no-one has mentioned. We do not need to build and instrument the greenhouses.
SD Silverstein (who he?) did exactly this in a 1976 paper entitled “A Clarification of the Greenhouse Effect”.
He used an atmospheric temperature of 0 degrees C, an interior temperature of 21 degrees C, and he calculated the radiative and convective heat flows (heat, not energy) from room to glass/rock salt interior, interior to exterior, and exterior to atmosphere. The radiative heat transfer from the interior was substantial, passing through the rock salt and being absorbed in the glass.
As a result, the glass was warmer than the rock-salt, 4.3 degrees against 2.5 degrees. But, consequently, the convection from the warmer glass was greater than from the cooler rock-salt, compensating for the much greater radiation through the rock salt to the atmosphere.
There is something for almost everyone in this analysis.
For RW Woods, Silverstein concludes that IR opacity or transparency is important but “this effect is more in the mix of different transport mechanisms than in the net thermal transport”. Increased convection balances reduced radiation, so the internal temperature is much the same.
Nevertheless, the figures do show the total thermal transport for the transparent case to be 18% greater than for the opaque case. So for the opaque greenhouse salesmen, the temperature differential might be a few degrees centigrade in favour of the glass house.
For the AGW advocates, Silverstein concludes that the IR-absorbing components of the atmosphere do provide a radiation shield, reducing the surface to tropopause radiation and hence the surface cooling.
For the AGW denialists, the corresponding effect of radiative warming of the atmosphere will increase the convective transfer to the tropopause, and the radiative cooling to space. The figures suggest that the difference between zero IR absorption and 100% absorption is a few degrees C.
For the direct atmosphere to surface, back-warming enthusiasts, Silverstein, like Sir Arthur Eddington and RW Woods, can offer no hope.
From Fargo: I have made a few graphite panels that emit 8-15 micron IR with 99.5 % efficiency via 110v ac input. The air does not heat up. However, objects and the floor do after which the air begins to warm and forms a slight upward draft. Reflection off glass cause the "R" value to double. Off other surfaces, the "R" jump is about 25%. Maybe a good experiment can be ran here because the energy input and conversion to IR is so efficient. There is a 10 deg F jump in temps at the surface due to the fold back of the reflected IR wave from the Bragg equation. Anyway, its got me thinking about Wood's experiment with the green houses.
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