A guest post by Ken Coffman and Mikael Cronholm
In clicking around on the Internet, I found an outstanding paper called Thermodynamics of Furnace Tubes – Killing Popular Myths about Furnace Tube Temperature Measurement written by Mikael Cronholm. The paper was clever and wise…and made a lot of sense. Clearly Mikael knows a lot about infrared radiation and I’m a guy with questions. A match made in heaven?
We exchanged e-mails. I want to be clear about this…Mikael corrected some of my wrong ideas about IR. I’ll repeat that for the slow-witted. Some of my ideas about infrared radiation were wrong. I am considered a hard-headed, stubborn old guy and that’s completely true. However, I want to learn and I can be taught, but not by knuckleheads spewing nonsense and not by authoritarians who sit on thrones and toss out insults and edicts.
Ken Coffman (KLC) is the publisher of Stairway Press (www.stairwaypress.com) and the author of novels that include Hartz String Theory and Endangered Species.
Mikael Cronholm (MC) is an industry expert on infrared radiation, a licensed, level III Infrared Training Center Instructor and holds two Bachelor of Science degrees (Economics and Business Administration).
The following is a summary of our conversation.
KLC: Hello Mikael. I found your paper called Thermodynamics of Furnace Tubes and I found it very informative, practical and interesting. I hope you’ll bear with me while I ask a couple of dumb questions. I am an electrical engineer, so I have some knowledge about thermodynamics of conduction and convection, but not so much about IR radiation. In return for your time, I would be happy to make a donation to the charity of your choice.
If I take an inexpensive IR thermometer outside, point it at the sky and get a temperature reading of minus 25°C, what am I actually measuring? Is there anything valid about doing this?
MC: Just as a matter of curiosity, how did you find my paper? I checked your website and I guess this has to do with the Dragon, no? If you want to make a donation I would be happy to receive that book. If you can, my postal address is at the bottom. I don’t follow the debate more than casually, but I am a bit skeptical to all the research that is done on climate change…it seems that the models are continuously adjusted to fit the inputs, so that you get the wanted output…and they argue “so many scientists agree with this and that”…well, science is not a democracy…anyway…
About radiation, then. There is more to this than meets the eye. Literally!
Looking at the sky with an infrared radiometer you would read what is termed “apparent temperature” (if the instrument is set to emissivity 1 and the distance setting is zero, provided the instrument has any compensation). Your instrument is then receiving the same radiation as a blackbody would do if it had a temperature of -25°C, if that is what you measure. It is a quasi-temperature of sorts, because you don’t really measure on a particular object in any particular place, but a combination of radiation, where that from outer space is the lowest, close to absolute zero, and the immediate atmosphere closest to you is the warmest. (I have once measured -96°C on the sky at 0°C ground temperature.) What we have to realize though, is that temperature can never be directly measured. We measure the height of a liquid in a common thermometer, a voltage in a thermocouple, etc, and then it is calibrated using the zeroth law of thermodynamics and assuming equilibrium with the device and the reference.
KLC: Global warming (greenhouse gas) theory depends on atmospheric CO2 molecules absorbing IR radiation and “back radiating” this energy back toward the earth. If you look at the notorious Ternberth/Keihl energy balance schematic (as shown in Figure 1 of this paper: http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/TFK_bams09.pdf ), you see the back radiation is determined to be very significant…more than 300W/m2. From your point of view as an IR expert, does this aspect of the global warming theory make any sense?
MC: The paper you sent me mentions Stefan-Boltzman’s law, but it does not talk about Planck’s law, which is necessary to understand what is happening spectrally. I suggest you read up on Planck and Stefan-Boltzman at Wikipedia or something. Wien’s law would be beneficial as well—they are all connected.
Planck’s law describes the distribution of radiated power from a blackbody over wavelength. You end up with a curve for each blackbody temperature. The sun is almost a blackbody, so it follows Planck quite well, and it has a peak at about 480nm, right in the middle of visual (Wien’s law determines that). The solar spectrum is slightly modified as it passes through the atmosphere, but still pretty close to Planckian. When the radiation hits the ground, the absorbed part heats it. The re-radiated power is going to have a different spectral distribution, with a peak around 10um (micrometer). Assuming blackbody radiation it would also follow Planck’s law.
S-B’s law is in principle the integral of Planck from zero to infinity wavelength. Instruments do not have equal response from zero to infinity, but they are calibrated against blackbodies, and whatever signal they output is considered to mean the temperature of the blackbody. And so on for a number of blackbodies until you have a calibration curve that can be fitted for conversion in the instrument.
That means that the instrument can only measure correctly on targets that are either blackbodies, or greybodies with a spectral distribution looking like a Planck curve, but at a known offset. That offset is emissivity, the epsilon in your S-B equation in that paper. It is defined as the ratio of the radiation from the greybody to that of the blackbody, both at the same temperature (and wave length, and angle…). Some targets will not be Planckian, but have a spectral distribution that is different. If you want to measure temperature of those, you need to measure the emissivity with the same instrument and at a temperature reasonably close to the one you will measure on the target later.
So, of course, the whole principle behind the greenhouse effect is that shorter wavelengths from the sun penetrates the atmosphere easily, whereas the re-radiated power—being at a longer wavelength—is reflected back at a higher degree. I have no dispute about that fact. It is reasonable. So I think the Figure 1 you refer to is correct in principle. My immediate question is raised regarding the numbers in there though. The remaining 0.9 W/m2 seems awfully close to what I would assume to be the inaccuracies in the numbers input to calculate it. You are balancing on a very thin knifes edge with such big numbers as inputs for reaching such a small one. An error of +/- 0.5% on each measurement would potentially throw it off quite a bit, in the worst case. But I don’t know what they use to measure this, only that all the instruments I use have much less accuracy than that. But with long integration times…well, maybe…but there may be an issue there.
KLC: I am interested in some rather expensive thermopile-based radiation detectors called pyrgeometers (an example is the KippZonen CGR 3 instrument http://www.kippzonen.com/?product/16132/CGR+3.aspx).
If a piece of equipment like this is pointed into the nighttime sky and reads something like 300W/m2 of downwelling IR radiation, what is it actually measuring? If I built a test rig from IR-emitting lightbulbs calibrated to emit 300W/m2 and placed this over the pyrgeometers, would I get the same reading?
MC: “What is it actually measuring?” Well, probably a voltage from those thermopiles…and that signal has to be calibrated to a bunch of blackbody reference sources to covert it either to temperature or blackbody equivalent radiation.
Your experiment will fail, though! If you want to do something like that, you have to look at a target emitting a blackbody equivalent spectrum, which is what the instrument should be calibrated to. IR light bulbs emitting 300W/m2 is simply impossible, because 300W/m2 corresponds to a very low temperature! Use S-B’s law and try it yourself. Like this: room temp, 20°C = 293K. The radiated power from that is 293K raised to the power of 4. Then multiply with sigma, the constant in S-B’s law, which is 5.67*10-8, and you get 419 W/m2 or something like that, it varies with how many decimals you use for absolute zero when you convert to Kelvin. For 300 W/m2 radiation I get -23.4°C at 300 W/m2 when I calculate it (yes, minus!). Pretty cool light bulb.
I don’t know what your point is with that experiment, but if it is to check their calibration you need a lot more sophisticated blackbody reference sources if you want to do it at that temperature. But you could do a test at room temperature though. Just build a spherical object with the inside painted with flat black paint, make a small hole in it, just big enough for your sensor, and measure the temperature inside that sphere with a thermocouple, on the surface. Keep it in a stable room temperature at a steady state as well as you can and convert the temperature to radiation using S-B’s law. You should get the same as the instrument. Any difference will be attributable to inaccuracy in the thermocouple you use and/or the tested instrument. Remember that raising to the power of 4 exaggerates errors in the input a lot!
I hope I have been able to clarify things a little bit, or at least caused some creative confusion. When I teach thermography I find that the more you learn the more confused you get, but on a higher level. Every question answered raises a few more, which grows the confusion exponentially. It makes the subject interesting, though.
Let me know if you need any more help with your project!
KLC: I found your paper because one of the FLIR divisions is local and I was searching their site for reference information about IR radiation. I know what a 100W IR lamp feels like because I have one in my bathroom. If someone tells me there is 300W/m2 of IR power coming from space, and I hold out my hand…I expect to feel it. What am I missing?
MC: Yeah, you put your hand in front of a 100W bulb, but how big is your hand…not a square meter, I’m sure. It is per area unit, that is one thing you are missing. The 100W of the bulb is the electrical power consumption, not the emitted power of the visual light from it. That’s why florescent energy-saving lamps as opposed to incandescent bulbs give much more visual light per electrical Watt, because they limit the radiation to the visual part of the spectrum and lose less in the IR, which we cannot see anyway. The body absorbs both IR and visual, but a little less visual.
And, here is the other clue. Your light bulb radiation in your bathroom is added to that of the room itself, which is 419 W/m2, if the room is 20°C. Your 300 W/m2 from space is only that. You will feel those 300 W/m2, sure. It will feel like -25°C radiating towards your hand. But you don’t feel that cold because your hand is in warmer air, receiving heat (or losing less) from there too.
Actually, we cannot really feel temperature—that is a misconception. Our bodies feel heat flow rate and adjust the temperature accordingly. It is only the hypothalamus inside the brain that really has constant temperature. If you are standing nude in your bathroom, your body will radiate approximately 648 W/m2 and the room 419 W/m2, so you lose 229 W/m2. That is what you feel as being cooled by the room, from radiation only. Conduction and convection should be added of course. The earth works the same way—lose some, gain some. It is that balance that is being argued in the whole global warming debate.
KLC: I still feel like I’m missing something. IR heat lamps are pretty efficient, maybe 90%? Let’s pick a distance of 1 meter and I want to create a one-square meter flooded with an additional 300W/m2. It must be additional irradiation, doesn’t it? That’s going to take a good bunch of lamps and I would feel this heat. However, I go outside and hold out my hand. It’s cold. There’s no equivalent of 300W/m2 heater in addition to whatever has heated the ambient air.
Perhaps I’m puzzled by something that is more like a flux…something that just is as a side-effect of a temperature difference and not really something that is capable of doing any work or as a vehicle for transporting heat energy.
It’s a canard of climate science that increasing atmospheric CO2 from 390PPM to 780PPM will raise the earth’s surface temperature by about 1°C (expanded to 3°C by positive feedbacks). From my way of thinking, the only thing CO2 can do is increase coupling to space…it certainly can’t store or trap energy or increase the earth’s peak or 24-hour average temperature.
Any comments are welcome.
MC: Efficiency of a lamp depends on what you want, if heat is what want then they are 100% efficient, because all electrical energy will be converted to heat, the visible light as well, when it is absorbed by the surrounding room. If visible light is required, a light bulb loses a lot of heat compared to an energy saving lamp. Energy cannot be created or destroyed—first law of thermodynamics.
When you say W/m2 you ARE in fact talking about a flux (heat flow is what will be in W). If you have two objects radiating towards each other, the heat flow direction will be from the hotter one, radiating (emitting) more and absorbing less, to the cooler one, which radiates less and absorbs more (second law of thermodynamics). The amount of radiation emitted from each of them depends on two things ONLY, the temperature of the object and its emissivity. So radiation is not a side effect to temperature, it is THE EFFECT. Anything with a temperature will radiate according to it, and emissivity. (If something is hotter than 500°C we get incandescence, emission of visible light.) Assuming an emissivity of unity, which is what everyone seems to do in this debate, the radiation (flux. integrated from zero to infinity) will be equal to what can be calculated by Stefan-Boltzmann’s law, which is temperature in Kelvin, raised to the fourth power, multiplied by that constant sigma. It’s that simple!
With regard to your thought experiment, it is always easier to calculate what an object emits than what it absorbs, because emission will be spreading diffusely from an object, so exactly where it ends up is difficult to predict. I am not sure where you are aiming with that idea, but it does not seem to be an easy experiment to do in real life, at least not with limited resources.
CO2 is a pretty powerful absorber of radiated energy, that fact is well known. Water vapor is an even stronger absorber. In the climate debate it is also considered a reflector, which probably also true, because that is universal. Everything absorbs and reflects to a degree. So I guess that the feedback you mention has to do with the fact that increasing temperature increases the amount of water vapor, which increases absorption, and so on. But my knowledge is pretty much limited to what happens down here on earth, because that is what matters when we measure temperature using infrared radiation. However, it is important to remember, again, that we talk about different spectral bands, the influx is concentrated around a peak in the visual band and the outgoing flux is around 10 micrometer in the infrared band, and the absorption may not be the same.
With so many scientists arguing about the effects of CO2 I am not the one to think I have the answers. I really don’t know what the truth is. And the problem that all these scientists have is that they will never be able to test if their theories are correct, because the time spans are too long. For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.
If not, it is not science, it is guessing.
More like a horoscope…
Will, the warmers often pipe up about sceptic “pseudo-science”.
It seems that you are our Al Gore.
Don V says February 18, 2011 at 11:50 am
Apart from conflating the impact of the illustration with sublimation and pressure change, no. The data largely came from Engineer’s Toolbox (e.g. for water vapour). Feel free to elaborate and correct, I’m all ears.
Robert Clemenzi says:
February 19, 2011 at 8:05 am
Bill Illis says:
“Something else is going on in the real world.”
It is called the greenhouse effect. Conduction and convection keep the days cooler than expected. Radiation from the sky keeps the nights warmer than expected. Think of the poles, with 6 months of no Sun they should be close to absolute zero.
———————————
Certainly, its clear that the relative warmth of the air over the pole doesn’t come from sunshine at the pole when there isn’t any.
What’s not so clear is that this story of radiating to the surface makes any sense at all.
It’s the air temperature we’re interested in. That’s what we measure (or, guess at). That’s what makes us put on our coats, or take them off. We are not running aound sticking thermometers in the snow and declaring that the air has warmed it.
Conduction and convection are accepted mechanisms for cooling in the lower latitudes and that’s how the arctic stays toasty.
The picture evoked is a static sky beaming down on the frigid landscape. The reality is more dynamic, even if the pace seems rather sedate.
The lapse rate is largely inverted at the pole, the radiative flow from the shorter atmosphere is upwards, the air circulates from equator to pole and back again.
The lower atmosphere at the pole is warmer than you might expect but not warmer than the air above it, which is radiating away to space, cooling and descending. Then it’s slithering down south so it can get warmed up again. Sometimes, it passes through Tulsa.
The fact that some photons are absorbed by the snow is not very important.
[Ta very much Mods, greatly appreciated]
barn E. rubble says:
February 19, 20100 at 7:17 am
RE: Myrrh says: “So, two things here. First, the 80% of Sun’s radiance being in IR…”
Is there agreement among posters in this thread with that statement?
🙂 I think it’s fairly safe to say that the consensus opinion here is that consensus in science isn’t a principle in science. A fact is a fact, regardless how many vote for it.
Well, from my post Feb 18, 7:46 am – if the example given of a billet of steel is anything to go by, it doesn’t seem unreasonable that most of the energy from a very hot object will be in IR. The examples of hot objects given included hot embers and lightbulbs, but see Feet2theFires post I’ve been mentioning re emissivity. I leave it to you or others to work out what % IR that would be coming from the Sun, assuming the same ratio of temp to IR as the steel is a good a start as any, my calculator’s broke..
RE: “AGW claim is that Infrared is mostly unable to get through our atmosphere, so therefore irrelevant to heating the Earth directly..”
Again, among the posters here, is the above a mostly true or mostly false claim?
It’s standard AGW. Your best bet here is to google ‘global warming energy balance’ or some such wording and look at the sites that come up from the AGW perspective. Here’s one: http://www.windows2universe.org/earth/Atmosphere/earth_atmosph_radiation_budget.html
With pretty graphic, it says: “A relatively narrow “window” of EM wavelengths around visible light reaches the ground. It includes some of the longer wavelength UV frequencies, some of the shorter wavelength IR frequencies, and all of the visble light region of the spectrum.”
Most of the longer wavelength IR waves, and many of the shorter radio waves, are absorbed by the stratosphere before reaching the ground. There is a sizeable “radio window” of radio wave frequencies that also reach terra firma.”
One thing commonly found in looking into such AGWScience is that it is never simple to get an explanation about any of it, because AGW avoids explanations. This leads to immense confusion even among AGW’s and is like wading through sticky toffee for anyone exploring, and one often has strange encounters with such consequences. AGW promotion of the idea of “blanket of greenhouse gases” for example, had some people seriously taking out a patent to deal with this “layer of gases in the atmosphere” – http://www.lightwatcher.com/chemtrails/Hughes_patent.html
(I’m posting this after having looked up Welsbach patent and found many references to it being real, but it still seems to me a “spoof”, I can’t quite get my head around how absurd this is.)
I have seen the explanation “absorbed by the stratosphere” for longwave IR, but so far have been unable to find any explanation of how this happens. Maybe you’ll have more luck or someone else knows. As I said earlier, the only explanation I’ve found is that it is absorbed by water and greenhouse gases before it reaches the ground. And although the explanation is often given that some of this ‘captured’ long wave IR is radiated to earth, it is then ignored.
So, what it, AGW, begins with is the idea that only a narrow window of energies reach earth, in the picture it’s called Optical “window”, you’ll often find it called “the Solar energies”, but it amounts to long wave UV, the Visible Spectrum, and Near Infrared. Near Infrared as noted in my above, is not considered Thermal/Heat Energy in sciences operating outside of AGWSpeak; Heat Energy is Mid and Far IR.
Most of the time AGW simply ignores this Near IR as a separate entity in basic diagrams and lumps it into “Visible Light” from a very hot Sun, and this, it says, is what heats the Earth, which then radiates back heat as far IR. One strange consequence I’ve seen is some AGW’s think Near IR is visible.
Now, I haven’t explored radio waves…, and deciding to take a quick look to see what I could find agreeing and disagreeing with this and the whys, I found: http:www.scribd.com/doc/14676816/E-E-RICHARDS-Earth-Power-Spectrum. I get easily distracted when exploring and so for the moment will avoid this tangent and stick with the IR problem presented here by the AGW scenario.
Bearing in mind that, as I have found generally, AGW explains the lack of mid and far IR reaching earth by saying it gets absorbed by water and carbon dioxide and only part of this is then re-emitted to earth and it doesn’t then bother with how much of this is reaching Earth, it doesn’t bother itself with Mid either, wouldn’t want anyone to start investigating the difference.., so it’s Near IR if mentioned at all, within Solar Energy, and longwave/far/thermal IR only. This wiki page is pretty much standard: http://en.wikipedia.org/wiki/Greenhouse_effect
@barn E. rubble, February 19, 2011 at 7:17 am
(This was written last night but my internet connection went down, so it is a delayed post.)
Clothes in a sauna?!?! Ridiculous! That’s like wearing clothes when you take a shower. People who cannot bear other people’s nudity will have to sauna alone, missing the important social aspect. In many countries business is done on the golf course. Guess where it is done in Finland? (Basically saying; I agree with your Dad!)
Anyhow, about your questions:
“RE: Myrrh says:
“So, two things here. First, the 80% of Sun’s radiance being in IR . . .”
Is there agreement among posters in this thread with that statement?”
No, there is not, and I think the best answer was made here, comment and partial quote:
“George E. Smith says:
February 15, 2011 at 11:54 am
For a start, the solar spectrum received at earth contains 98% of its energy essentially in the wavelength range from 0.25 microns in the UV to 4.0 microns in the IR, with only 1% left over at each end. Ozone of course cuts off the short end at about 0.3 microns. About 2.5% of solar radiation lies below 300 nm.”
I totally agree with George on that, based on my understanding of Planck’s Law (which Myrrh “falsified” using data obtained with….. Planck’s Law!).
Then this one:
““AGW claim is that Infrared is mostly unable to get through our atmosphere, so therefore irrelevant to heating the Earth directly . . .”
Again, among the posters here, is the above a mostly true or mostly false claim?”
I would agree that very little heat from infrared radiation would be absorbed by the surface of the earth through the atmosphere, firstly because according to the above, very little energy reaches TO the atmosphere in the first place and secondly because even IF any significant IR reaches the “outside” of the atmosphere, it would have a real hard time getting through it. We have to keep the logarithmic scale of the Planck curves in mind when we look at them.
And then there is the so called greenhouse effect that I believe is for real (although it has not been so clearly defined so I may be confused about it), and necessary for our survival on this planet. IR radiation from earth will not radiate easily towards the cold space, but be trapped in the atmosphere to a degree. Some of the heat in the atmosphere must be in the form of latent heat in the water vapor itself and it keeps our planet from cooling off too much. This has been happening for millions of years, the balance has been shifting back and forth and warmer and colder periods have been taking place for a variety of reasons – in combination! I am just not very sure about these mechanisms, but somehow there is a balance between heating and cooling that keeps us at a comfortable equipibrium.
I think it is important to make a distinction between “green house effect” and “global warming”. Greenhouse effect as such is necessary and not an evil thing, if the term means what I think it does. We depend on it. The other claim that CO2 emissions cause an additional warming effect – that is compounded with an increase of the greenhouse effect – is the part that I feel is not proven at all. This is where all the politics and prestige comes into the picture and as a crowning of it, even fraudulent behavior from scientists.
So there we go, I think that in addition to replying to your very well chosen questions I was also promted to sum up my personal standpoint at this time. Subject to continuous scrutiny and revision of course!
Will says:
February 19, 2011 at 7:53 am
Mikael, Phil and whoever is still reading this thread and Ken,
Firstly to address the criticism of my experiments, which incidentally I have not mentioned once on this thread, I will simply say the following. I have many variations on these experiments, using different heat sources from IR halogen heaters to candles and plain old sunlight in a south facing window: “AGW Debunked again.pdf”
But none of those light sources have any relevance to the Greenhouse Effect, for that you would need a solid object at a temperature of ~300K, the problem is there is no simple experiment to demonstrate it under realistic conditions. All sorts of temperature and material problems.
It makes no difference what type of plastic these bottles are made of or what the heat source is, the result is always a bias of 1 degree towards the Air bottle. Argue the semantics all you like, it doesn’t change that fact. I am not interested in arguing semantics, it is simple, produce an experiment that proves I am in error or shut up already.
Design an experiment that simulates the Greenhouse Effect and we’ll have something to talk about, the experiments you describe are far removed from that. You’ll need to have a light source corresponding to a blackbody at 300K (peak wavelength ~10μm), and a container transparent up to ~20μm (ZnSe would probably work although a 1/2″ diam window will cost over $100). Have at it.
@ur momisugly Phil. Creating a 300K source is no problem at all, since it correspond to about 27C. The problem is to simulate the atmosphere and space. That is not something you do in a kitchen! Using ZnSe windows we could probably create a slightly less stupid experiment than the plastic bottle one, and then tell Will to shut up until he makes a better one than that. But it is pointless. Creating one flawed experiment after the other makes very little sense. What is important is not to believe charlatans…
In the end, the burden of supplying proof rests instead on those that claim CO2 is responsible for warming the earth. None of that has been presented so far and it will be difficult to do. It brings me back to what I ended the discussion with Ken with:
“…the problem that all these scientists have is that they will never be able to test if their theories are correct, because the time spans are too long. For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.
If not, it is not science, it is guessing.”
Myrrh says:
“Is there agreement among posters in this thread with that statement?
🙂 I think it’s fairly safe to say that the consensus opinion here is that consensus in science isn’t a principle in science. A fact is a fact, regardless how many vote for it.”
That is so true! Completely agree!
Michael,
Please read carefully the following quote: “THE SIMPLE TEST A comparison of the Infrared absorption of CO2 against ordinary Air.”
See that is what is clearly stated at the link.
“AGW Debunked again.pdf”
You have falsely implied that I have attempted to model the “greenhouse effect”.
Yet I have clearly stated that it is a simple gas comparison test. I would not try to model something which cannot and has not been shown to exist. What would be the point in that.
The technique of perpetually taking me out of context in order to claim I am in error is a trick you have repeatedly used on this thread Mikael, shame on you Sir.
Phil,
What temperature do you think my house is for Christ’s sake, and who do you think you are fooling?
This is a “science blog” where interested folke come to learn things. Not to be led up the garden path.
Nobody has provided a legitimate criticism of these simple experiments. Just out of context ad hom and sophistry dressed up as science.
Any fool can criticise a video or an image with some text, what does that prove? Like I said, perform an experiment which proves mine is wrong, or shut up about it.
barn E. Rubble says:
“RE: Myrrh says:
“So, two things here. First, the 80% of Sun’s radiance being in IR . . .”
Is there agreement among posters in this thread with that statement?
“AGW claim is that Infrared is mostly unable to get through our atmosphere, so therefore irrelevant to heating the Earth directly . . .”
Again, among the posters here, is the above a mostly true or mostly false claim?
———————————-
1. AFAIK , around 50% of the total energy is IR.
2. It is strongly absorbed by water vapour and other absorbing gases and particles fairly high up. It warms the air, not the surface, but is not irrelevant.
Will says:
February 20, 2011 at 5:46 am
Michael,
Please read carefully the following quote: “THE SIMPLE TEST A comparison of the Infrared absorption of CO2 against ordinary Air.”
Which can be done much more effectively with a spectrometer, such as here for instance:
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2spectra-1.gif
See that is what is clearly stated at the link.
“AGW Debunked again.pdf”
You have falsely implied that I have attempted to model the “greenhouse effect”.
Well in order to ‘debunk AGW’ it would be important to conduct an experiment at conditions relevant to AGW! Something you failed to do.
Yet I have clearly stated that it is a simple gas comparison test. I would not try to model something which cannot and has not been shown to exist. What would be the point in that.
The technique of perpetually taking me out of context in order to claim I am in error is a trick you have repeatedly used on this thread Mikael, shame on you Sir.
So stop claiming to have debunked something when your experiment could not possibly do so, that is the context that you claim.
Phil,
What temperature do you think my house is for Christ’s sake, and who do you think you are fooling?
This is a “science blog” where interested folke come to learn things. Not to be led up the garden path.
The only one ‘leading up the garden path’ is you, your experiment is not science it’s junk!
The ‘G’ stands for globe and refers to the following situation:
A solid sphere in the vacuum of space, heated by the sun at ~5800K (peak emission ~0.5μm), achieves a surface temperature ~300K by radiational exchange through an atmosphere to space at ~4K.
Your experiment, a hollow vessel filled with CO2, heated from outside by a heater at ~2000K (~2μm?) in an atmosphere at 1bar exchanging heat with its surroundings at 300K via radiation, conduction and convection.
Nobody has provided a legitimate criticism of these simple experiments. Just out of context ad hom and sophistry dressed up as science.
Really perhaps you should try reading, starting above.
Your experiment has all the parameters wrong for a comparison with AGW as shown above. Even then it is unlikely to measure what you think it does!
You compare a sample of wet air with wet CO2, the CO2 is at a higher pressure than the air and consequently will have a higher heat capacity (CO2 has a higher molar Cp too). You illuminate both with Near IR probably peaking around 2μm so that if there is any absorption by CO2 it will be in the 2.7μm and 4.3μm bands which are weakly activated by the solar spectrum. However that light has to pass through the vessel walls and it is the wall temperature which you are measuring not the gas temperature. None of the variables are well controlled, in short it’s a terrible experiment and goodness knows what it’s actually responding to, most likely radiational heating of the plastic and heat loss to variable heat capacity enclosed gas, but that’s nothing to do with AGW.
Mikael Cronholm says:
February 19, 2011 at 8:06 pm
@ur momisugly Phil. Creating a 300K source is no problem at all, since it correspond to about 27C. The problem is to simulate the atmosphere and space. That is not something you do in a kitchen! Using ZnSe windows we could probably create a slightly less stupid experiment than the plastic bottle one, and then tell Will to shut up until he makes a better one than that. But it is pointless. Creating one flawed experiment after the other makes very little sense. What is important is not to believe charlatans…
Quite so, but when those charlatans post here like Will does it’s important to rebut them lest readers believe their nonsense. While there are many things wrong with Will’s experiment to design a good one isn’t easy, and it certainly isn’t cheap.
REPLY: Will’s been put in the troll bin for thread bombing his plastic bottle nonsense. I’m going to routinely delete his posts from now on, simply because he’s incapable of listening to others when we point out he has the basis of his experiment all wrong. – Anthony
[snip – take your plastic bottles IR experiments elsewhere, your fatally flawed commentary is no longer welcome here – Anthony]
Thank you Anthony
Robert Clemenzi says:
February 18, 2011 at 1:17 am
http://www.coe.ou.edu/sserg/web/Results/Spectrum/o2.pdf and http://www.coe.ou.edu/sserg/web/Results/Spectrum/n2.pdf show the IR spectra of O2 and N2, respectively. Unfortunately, there are no spectra for H2O and CO2 for comparison.
Actually there are at the same site that you get those from. To save trouble here are the spectra for CO2, N2 and O2, plotted on the same graph:
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png
and here is the BB emission spectrum on approximately the same scale:
http://i302.photobucket.com/albums/nn107/Sprintstar400/BB.png
Note that the scale of the first graph is log base 10 so that the N2 and O2 bands are many orders of magnitude weaker than the CO2 bands, also in the region where they show up is an H2O peak which also swamps them by a similar margin.
Mikael says to barn E. rubble
February 19, 2011 at 5:12 pm
barn E. rubble Re: Myrrh says: “So, two things here. First, the 80% of Sun’s radiance being in IR..”
Is there agreement among poster in this thread with that statement?
Mikael replies: No, there is not, and I think the best answer was made here, comment and partial quote:
George E. Smith says: “For a start, the solar spectrum recieved at earth contains 98% of its energy in the wavelength range from 0.25 microns in the UV to 4.0 microns in the IR, …”
Mikael says: I totally agree with George on that, based on my understanding of Planck’s Law (which Myrrh “falsified” using data obtained with … Planck’s Law!).
Hmm, not all energy is heat. Most of that then, not that I’m agreeing with the division here, is of Visible Light Energy which ain’t so hot, visible light is not heat carrying, it doesn’t warm up things. You can shine a yellow light, hey let’s go for peak, white light at your kettle and you’d be waiting a long time for your tea. You haven’t falsified Herschel. The greatest amount of energy is in the Thermal IR.
Here, perhaps I’m just not very good at explaining it: http://www.newton.dep.anl.gov/askasci/eng99/eng99505.htm
Light Bulb Color and Temperature
name Shawanna
status student
grade 4-5
location MD
Question – Do different color light bulbs produce different amounts of heat?
—————————————-
Hi Shawanna,
There is no significant difference in the amount of heat produced, between different color of light bulbs of the same wattage.
To give you a little more detail, all standard filament-type lights waste around 95% of their power as heat, and only about 5% of the power they use is used to make white light.
So, a 100 watt light bulb may be using 100 Watts of electrical power, but it is producing only about 5 Watts of actual white light, and a whopping 95 Watts of heat!
Etc. Likewise the Sun. It takes heat to create the colours, that does not mean the colours are that heat, nor that colours can produce that amount of heat. All the colours show is the temperature of the object generating the colours.
As my example re the steel billet explained, a skilled steel worker can tell from the colour how hot the steel is. And the punchline – that a steel billet at X, scroll up yourselves, produces 100,000 times as much IR as Visible Light.
Which is all I was saying re the Planck thingie, the peak energy should be in IR which is what is most produced by a heated object. And if the light bulb to steel at temp X may be a ‘relative constant’ of some sort, on a sliding scale 19 times for 100 Watts through to the steel 100,000 times and to the sun X times as much?
So, anyway, what we have in AGW is this ridiculous notion that Visible Light heats the Earth. Example on this wiki page, which some here can tell you was totally corrupted by AGW control, but that’s another story.. Anyway, look up Thermal radiation and you’ll find this:
Examples of thermal radiation are an incandescent light bulb emitting visible-light, infrared radiation emitted by a common household radiator or electric heater, as well as radiation from hot gas in outer space. A person near a raging bonfire feels the radiated energy of the fire, even if the surrounding air is very cold. Thermal radiation is generated when thermal energy is converted to electromagnetic radiation by the movement of the charges of electrons and protons in the material. Sunlight is solar electromagnetic radiation generated by the hot plasma of the Sun, and this thermal radiation heats the Earth by the reverse process of absorption, generating kinetic, thermal energy in electrons and atomic nuclei. The Earth also emits thermal radiation, but at a much lower intensity and different spectral distribution because it is cooler. The balance between heating by incoming solar radiation and cooling by the Earth’s outgoing radiation is the primary process that determines Earth’s overall temperature.
AGW says Solar electro-magnetic radiation is sunlight, this means the Visible Light spectrum, and it’s this which heats the Earth by generating kinetic, thermal energy in electrons and atomic nuclei, the opposite of absorption (which is how thermal IR heats), I put this in italics.
Note it precedes this by saying the thermal radiation of the sun produces sunlight, but doesn’t say it produces thermal energy, so only kinetic production is used in their “Energy Budget”.
It is ignoring the real thermal radiation heating the Earth, by absorption of Thermal Energy itself, mid and long wave IR.
If a 100 Watt light bulb produces 95% Heat/Thermal Energy, how much is the Sun producing? It reaches us in the same 8 minutes as Visible Light, remember.
Like I said, AGW ignores the real heat source actually heating the Earth, Thermal IR.
If you look at the AGW diagrams you’ll notice that none of the thermal energy which is the real peak of energy, is used to calculate the heating of the Earth. Not even, as I said earlier, the thermal IR absorbed by water in clouds and water vapour and also heating the atmosphere and “radiating back to Earth” in some of the AGW scenarios..
If you look at the diagrams, you’ll notice rather a lot of thermal IR being radiated back from the Earth.
George and Mikael, please show me, and barn E. rubble, the experimental data which proves that Visible Light, Sunlight, is kinetically heating the Earth to such an extent as to produce this amount of Thermal Energy radiating back into the atmosphere from the Earth.
http://climateaudit.files.wordpress.com/2008/01/balanc3.jpg
What this does to Planck, I have no idea. What it does to AGW should be obvious to you all now. It’s JunkScience.
@ur momisugly Myrrh. For your own sake, please listen: You need to spend a little time learning how Planck, Stefan-Boltzman, and Wien work, and how they are related. It is pointless to discuss with you before you understand those things. You can try and turn things upside down, inside out as much as you want, it will not change these very basic laws of science!
A white car and a black car will have the same absorptivity in the IR, and yet the black one gets hotter when they stand in the sun beside each other. The white car reflects more of the visible light from the sun, while the black one absorbs more of it. Is that impossible for you to understand?
Myrrh says:
February 20, 2011 at 2:15 pm
“Here, perhaps I’m just not very good at explaining it: …”
————————————-
I have to agree with that statement.
I don’t think you’ll find many claiming that an object at 300K is emitting most of its energy as visible light. I believe that you might emit one photon of visible blue in 10,000 years. As long as you don’t cool down too much in the interim.
Not even at 6,000K. In addition to IR, there’s UV and x-ray.
I don’t think you’re talking to many AGWers here but, equally, few would accept that the atmosphere is heated from the top down, except for during the polar nights and that’s about convection.
Mikael – stop avoiding what I’m saying. Answer my post and no more prevarication.
YOU HAVE STILL NOT PROVED WHAT YOU CLAIMED.
YOU SAID UV AND VISIBLE LIGHT PENETRATE DEEPER THAN IR.
If you can’t handle my post, exactly as I have presented my argument, and if you continue to offer no proof of what you have claimed, then, there’s nothing more to say. Except, if you can’t answer these, why are you claiming to have knowledge of them?
barn E. rubble, make up your mind. And bear in mind, to my experience, that people answering by throwing ‘laws’ at you with such disdain as shown here while unable to answer contradictions, either don’t know the laws themselves, which includes their limitations, or are bluffing because they can’t answer you. Note well, that Mikael’s last reply to me about cars has got nothing, zilch, to do with what I am saying and asking him.
It’s simply bloody obvious, that there is more thermal energy given off by a hot body than visible light. They are like for like electro-magnetic energies. The Planck “peak” might well be in the shorter wavelengths. But that cannot be saying as George said and Mikael agreed, that this means 98% of the energy given off by the sun is in the wave lengths George said with any implications that this means Visible light is in that in any amount except as a minor contributor to the total energy coming from the Sun.
In other words, be careful how things are phrased. Remember the light bulb, 5%-95% of light energy to heat energy.
Oliver – that’s exactly what is being claimed by AGW. I’m sorry I’m not explaining myself well enough for you, perhaps if you actually followed it with more attention given my obvious limitations, you would have seen that by my examples from AGW’s own bumf. The wiki article is specific on this. The Earth is not heated by absorption but by kinetic energy from the Visible light spectrum, a.k.a. Solar Energy. AGW takes downwelling Thermal energy out of the equation.
And who said anything about the atmosphere being heated top down? Light reaching us in 8 minutes from the sun includes the major component, Thermal IR. The heat we feel on earth standing in the Sun light is not from the Visible light energies, but from the Thermal IR. That is reaching us even if we are in a cold atmosphere, like sitting in front of a fire in a cold room, we’ll be feeling the heat while our backs are cold, so on some Alpine slope in the Sun light; and it reaches us at the same time as the Visible energies reach us. We are warmed from the Earth up by absorption, not by kinetic AGW twaddle.
@ur momisugly Myrrh.
You say: “… of Visible Light Energy which ain’t so hot, visible light is not heat carrying, it doesn’t warm up things.” Wrong, which is what the car example aimed at, but you did not understand. Visible light, when absorbed, will heat things up. The two cars will absorb equally in IR, but the white one will reflect more of visible and the it why it is cooler when it is standing in the sun. So the visible is the difference, which it could not have been if it could not transfer heat. If you cannot get your head around that, what can I do?
You also do not believe the numbers George gave you that I agreed with.
http://en.wikipedia.org/wiki/File:Solar_Spectrum.png
Well, there is a a set of three curves (solar radiation on the outside of atmosphere and on earth, compared with blackbody) that will show you that the sunlight has the most intense energy flow (which becomes heat when absorbed by the earth) in the visible part. There is also a lot in the near IR, but not much over 2.5um, which is what I pointed at re. Herschel. There would have been very little energy in the longer wavelengths and they would have been blocked by the glass prism anyway.
And please stop assuming that I have any obligation to prove anything to you. You claim that I am unable to show you, when in fact you are unable to understand.
@ur momisugly Myrrh. BTW: “The Planck “peak” might well be in the shorter wavelengths.” It may, it may not – it depends on the temperature of the object where the peak end up! Every temperature has it own Planck curve… learn!
Myrrh says:
February 20, 2011 at 5:51 pm
Mikael – stop avoiding what I’m saying. Answer my post and no more prevarication.
YOU HAVE STILL NOT PROVED WHAT YOU CLAIMED.
YOU SAID UV AND VISIBLE LIGHT PENETRATE DEEPER THAN IR.
Here’s the absorption spectrum for liquid water (blue curve), note the 8 order of magnitude drop-off from the near IR to the UV (300nm).
http://www.btinternet.com/~martin.chaplin/images/watopt.gif
@Myrrh
Okaaaay…. could you give me your version of what happens, up close, when an IR photon encounters a water molecule, in the midst of a whole bunch of other water molecules at a partial pressure of 10 millibars? Let’s add some N2 and O2 to make a total pressure of 1,000 millibars.
Then, a snapshot of a photon at 400 nanometres doing the same thing.
Please, don’t leave out the vibrational bits, or the translational stuff. Are electrons involved? Is there such a thing?
@ur momisugly Phil. Thanks! I had a feeling it should look something like that.
And if we consider that us humans consist of about 2/3 of that stuff, I think Myrrhs alternative medicine healers had better not show that to their patients.
In fact, thanks to Myrrh, I am learning and finding out a lot of stuff from this discussion.
Why don’t you answer my actual questions? Deal with my actual points made? barn E. rubble asked specific questions, I did my best to answer him, my answers make sense, yours are either distractions or irrelevant or plain daft.
Your car example is the same as the, quite frankly, stupid, BBC promotion of AGW in their experiment to show how dreadfully hot carbon dioxide became by heating a jar full of carbon dioxide and a jar full of air.
How long have you given the two cars to heat up? And critically, which cools down more quickly?
Check out Wien, 2nd Law Thermodynamics and the Osanger reciprocity principle. Like the AGW ‘back-radiation’ from Carbon Dioxide will keep heating up the Earth and set up a runaway global warming your black car will just keep getting hotter and hotter… None of you really understand these laws, do you?
barn E. rubble asked two questions. You have not shown him any proof that I am wrong in the answers I gave him.
Are you unable to concentrate? I know I get easily distracted, but your avoidance is bordering on something else perhaps…
Nor have the two, George and Mikael, given him any proof of their viewpoint.