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 says:
February 18, 2011 at 7:21 am
Ken and Mikael,
I have repeatedly given Mikael the opportunity clear up the ambiguity concerning the statement that glass is opaque to IR, by repeatedly adding the following caveat “as in that it acts as a barrier to IR.”
Yet he has consistently failed to clarify that this is a misconception of the word opaque.
The use of the word opaque and the phase “opaque to IR” in this context, is the source of a very serious misrepresentation of what occurs inside a greenhouse. It implies, as is perfectly obvious, that glass somehow blocks the passage of IR. Yet as has been demonstrated by Mikael’s link, glass certainly does not block IR because above 4 µm it is almost a pure black-body absorber and emitter. This means that IR is absorbed and emitted by the glass at light speed. As the interior of the greenhouse is always going to be warmer than the exterior, it naturally follows that the IR energy will pass through the glass to the exterior with the same ease as if it were “transmitted” and in that case the use of the phrase “opaque to IR” is pure semantics with the intention to deceive. Sometimes referred to as sophistry.
Not only has Mikael allowed this misconception of the use of the term “opaque to IR” to imply that glass presents a barrier to the passage of IR (the foundation of the “greenhouse effect hypothesis”) but in the example I have given regarding the IR sensor on my outdoor security light, which is empirical proof that glass does not block IR, he has failed acknowledge that this is the case and has allowed Domenic’s false claim that this test is invalid, to stand unchallenged.
This is a deliberate fraud, directly and by proxy.
No it’s a misunderstanding of the physics on your part.
Borosilicate glass cuts off around ~2μm above that it’s increasingly opaque to IR.
As a pure blackbody it does not transmit IR it absorbs it and emits bb radiation back.
The illuminators used with IR security cameras are typically at ~0.8μm just in the NIR and still able to pass through borosilicate glass. However such glass is completely opaque to 15μm IR which is responsible for the GHE, to work at that wavelength you’d need something like ZnSe optics which is transparent at that wavelength. Which is why experiments like Will’s are totally irrelevant to GHE, they use the wrong wavelength and if they used the right one the materials their containers are made of aren’t transparent at that wavelength! Will’s experiment uses heaters which are in the 1-2μm range which would be relevant if the surface of the planet were ~2000K!
Myrrh says:
February 18, 2011 at 5:01 am
“But, in a sauna one can choose whether or not to dump water onto the rocks, making it a dry sauna. Do the Fins never do this?”
Not that I’m aware of, in fact, splashing down the walls and benches is part of the prep. or so I was taught. Further, and in spite of what you may have heard, it’s not a ‘real’ sauna without a cold beer (optional: frozen vodka shot). To reiterate: there is no such thing as a ‘dry’ sauna; in any sense of the word ‘dry’. Add a dip in cool to cold water and things don’t get any better . . .
Thank you for your time and patience in your postings. Most appreciated.
-B
Will, I’m not sure why you are getting so excited. This is a fascinating topic worthy of thought and exploration…why are you not having any fun? No one is telling you what to believe. Look at what people say. Think things through. Draw your own conclusions.
Here is a bit of conversation about R. W. Wood’s experiment…perhaps you’ve already seen it?
We may well ask if it is at all possible for backradiation to coexist as a significant process alongside kinetic transfer. It would certainly seem possible within the limitations of thermal gradients. However, if we revisit the experiment conducted by Robert Wood in 1909, an entirely different picture emerges. Wood constructed two miniature greenhouses identical in all but one respect. One used a plate of halite to transmit light into the interior, while the other used a plate of glass to transmit light into the interior (Wood, 1909). While glass absorbs more than 80% of infrared radiation above 2900nm, halite does not and is regarded as quite transparent to infrared. The point of the experiment was to test whether the halite’s lack of absorption and re-emission of infrared radiation relative to that of glass would have any effect on the temperature of the greenhouse.
– Timothy Casey, The Shattered Greenhouse, http://greenhouse.geologist-1011.net/
@ur momisugly barn E. You make me homesick for my sauna back in Sweden! I am Swedish and my mother was from East Botnia in the Swedish speaking part of Finland, so sauna is in my blood so to speak. At my place in Sweden I built the two houses first and then the sauna, which is opposite to tradition – the sauna is built first in Finland! It is more than tradition, it borders on religion. The sauna is a home for spirits and the sauna gnome. The special sauna spirit has a name in Finnish, löyly, which is difficult to translate but it is the warmth and the feeling of well being, and it is surely connected with the steam too. It is an old word that traces back to Proto-Fenno-Ugric and has a counterpart in Hungarian meaning “soul”.
By using evaporation and condensation the heat from the rocks can be transfered in a very controlled way. Sauna is not about sweating but condensation on the skin. The more water, the hotter. Löyly! Dry “sauna” has no löyly… so you are right. I have never seen one in Finland.
My sauna has neither electricity or running water, even though it could be easily done. But it would take away the charm of the preparations, carrying the water in buckets, lighting the fire, the warm light from the paraffin lamp outside the window. You wash in the room itself, the water is mixed with hot from the heater on the chimney and cold from the buckets and it runs down through the floor and out on the ground.
Heating and cooling repetedly is important. A snow bath is great!
Sauna makkara is sauna sausage, smoked, tasty. Beer and vodka can join it, but after or late in the session. You feel better then. Sit outside and cool down in the semi darkness of the summer nights in the north. Good sleep.
Here in Thailand where I live now it feels a bit redundant with sauna, unfortunately…
(Sorry for going off topic!)
to Robert Clemenzi
Just two points
1. I don’t mean to be picky, I like your posts…actually dew is not just a morning effect, that’s just when most people wake up and see it…it can go on all night. I live in the Miami Beach area, and I have often observed dew forming on my car immediately following sunset.
2. regarding O2 and N2…you should have noticed that I also mentioned that they have to be tested for reflectivity and transmissivity at the long wavelengths. A gas molecule can be a very effective ‘greenhouse gas’ even with little absorption….if it’s reflection to long wavelengths is high, reflecting them around to be absorbed by H2O, etc, as well as reflecting them back towards earth.
AJB says: All your Joule are belong to us.
I followed the link you provided to find an illustration comparing the energy content of water, CO2 and N2 vs temperature, but unfortunately I have to disagree with the accuracy of what is depicted. The truth concerning water’s amazing properties, that this illustration should show, is even better! Can you find all that is wrong with this illustration?
@ur momisugly Ken. You got me all excited for a while there. “Halite”, hmm, what is that? Never heard of it and Ken says its IR transparent! The “wow” factor was a little less when I looked it up – sodium chloride. So I learned a new name for it. Anyhow, very early IR lenses and optics were made from it. It is one of the few cheap IR transparent materials, but not the only salt. Barium flouride and calcium flouride are salts too, and IR transparent (at best only at 90% up to 12um). But less cheap. Sodium chloride has the distinct disadvantages of being brittle and hygroscopic, so it cannot be used for making lenses for cameras. We are stuck with super expensive germanium, a metal, for the long wave cameras of today.
Phil, Ah well, I did wonder if I’d understood it; Mikael, glad you find it amusing.. Still, am I right in thinking Feet2theFire has falsified Stephan’s Law?
Mikael – Remains though, the problem that you’re still associating greater penetration with shorter wavelengths and, so far, you haven’t even attempted to prove that to me..
..distracting me by sending me off on wild goose chases doesn’t impress.
@ur momisugly Ken. You could actually recreate that experiment quite easily by using polyethylene film – food wrap – instead of the halite. It should have similar enough characteristics to halite, at least compared to glass.
Well as to my comments about “DRY” air; I am quite aware that real atmospheric air is never dry, in the sense that it contains NO H2O molecules. BUT that is precisely what I mean when I say “DRY air”. And that is simply to separate out the real King of greenhouse gases. CO2 from the non GHG H2O usurper, that is merely carrying the water (so to speak) for the true villain.
It also helps in that it removes the H2o absorption spectrum from consideration when it comes to the heating and radiation from the atmosphere.
Somebody way up the forum there (my apologies to the poster; but you can find him) stated, that the atmosphere blocks (is opaque) in some bands in just the bottom few metres, and that that warmer lower layer radiates more heat downwards tot he surface; whereas the higher cooler layers radiate much less upwards; ergo the atmospehric thermal radiation is concentrated downwards; and warms the surface.
So let’s examing the validity of that notion.
Consider a very thin atmospheric layer anywhere in the atmosphere (doesn’t matter where so long as it is in the lower 20 km or so); so for the moment shall we say our layer is at the standard Owl Box height of 2 metres; right where that thermistor is. A thermistor is a very poor excuse for a thermometer; but in this case it doesn’t matter.
Shall we say our thermistor (refuse to call it a thermometer) reads 288 K, 15 deg C or 59 deg F, the current assumed without proof mean Temperature of the earth. The S-B equation gives 390 W/m^2 (roughly) for this Temperature, for the total Black Body Radiation. Did I say that my atmospheric layer is just one micron thick.
So it is emitting (isotropically) 390 W/m^2 upwards and 390 W/m^2 downwards (TIMES EPSILON, the EMISSIVITY). Now more accurately we should use the spectral emissivity; but for the time being we’ll assume it is constant over the meaningful spectral range.
Now Wien’s Constant (b) is 2.897756E-3 m.K +/- 8.4 ppm, so that gives the peak of the LWIR spectrum to be 10.0616…. I used to call that 10.1, I’m going to go with 10.0 microns.
Also the peak spectral radiance is given by 1.288E-11.T^5 w/m^2/micron. which comes out to 25.51986…. ; I’ll take 25.52 Watts per m^2 per micron (of spectral bandwidth).
So now we are set to go. Taking the CO2 band center as 15 micron (nobody knows what it really is); that makes it 1.5 times the peak (of 10.0 micorns), and at 1.5 times the peak wavelength the BB spectral radiant emittance is 0.70 times the peak, which gives us 17.86 W/m^2/micron, at the CO2 band. Getting generous, and giving CO2 the entire 13.5 to 16.5 micorn spectral width or 3.0 microns total, we get 53.6 W/m^2 (times epsilon) for the up and down halves of the isotropic thermal radiation from my one micron thich layer.
And that radiant energy is 98% contained between 5.0 microns and 80 microns (0.5 to 8.0 times the spectral peak wavelength).
Now that energy is radiated from the ordinary atmospheric gases of N2, O2, and Ar that are all at 288 K Temperature. And note that only 53.6 out of 390 is capturable by CO2, that’s 13.7% of the Total thermal energy that can be captured by the CO2 in the layers immediately above and below my one micron layer; the rest goes right on through the adjacent one micron thick layers.
Now the layer above is colder than my layer, and less dense, so the doppler broadening and the collision (pressure) broadening in that higher layer, are less than in my emitting layer (not much but less anyhow). The air layer below, is slightly higher Temperature and slightly higher density, so both the pressure and doppler broadening are higher than for my layer; and in particular are higher than for the layer above me.
So I have 390 (epsilon) w/m^2 of identical radiation going upwards, and downwards; but the layer above has narrower absorption lines than the layer below, so the layer below is going to undergo CO2 absorption of slightly more of my 390, than will the layer above.
So both layers bordering mine, now absorb about 53.6 out of my 390 (don’t forget the emissivity) but the upper layer absorbs slightly less, so that more of the upward LWIR energy goes beyonf the upper layer, than goes beyond the lower layer.
Each of those layers will in turn thermalize that cO2 captured energy, slightly raising their Temperature. Well not really; those thin layers will cool rapidly due to their thermal radiation losses, if it was not for the contunuous resupply by the CO2 GHG trapping process. That is why those layers are at those Temperatures in the first place. Well don’t forget that conduction and convection etc can also bring more juice to my thin layer.
Now I gave my layer some numbers; just to have some numbers to talk around; but it should be obvious, even if you have never scratched on the beach sands with a stick, that it doesn’t matter where my layer is; so long as it is in the steadily declining density and Temperature range of the Atmosphere, the same situation applies. The escape route upwards, is favored over the return to earth downwards, byt those gradients and their line broadening effects. OK!, not by much to be sure; but certainly for sure.
It doesn’t matter that the one micron layer right at the ground iws radiating much more than the layer at 10 km altitude; it is still radiating isotropically, and the upper escape route is still favored over the return to earth.
I’m NOT going to claim a measurable difference; it’s the beat of a butterfly’s wing thing; but it is quite real, and it puts the lie to the notion that the atmospheric thermal radiation is biassed downwards towards the earth; it isn’t.
Now feel free to reintroduce H2o; bring on your own favorite GHG; where’s that fearsome 20 times methane monster.
I actually have a chart that purports to have a methane absorption spectrum. It has a very modest band at 8 microns, and a pitiful one at 3.3 microns, and a totally miserable one at 2.4 microns
Hey Earth to Atmosphere ! there isn’t any earth emitted LWIR energy at 3.3 or shorter microns; and at 8 microns the spectral radiant emittance is 86% of the peak (10 microns). Did I already say that only 25% of the total BB emission energy lies below the peak wavelength; and actually only 10% lies at less than .8; or 8 microns
Yes in the hotter desert Temperatures, the thermal peak will move towards the CH4 8 micron band.
You can do all of those things and though they change the absortion numbers; they do not change the fact that the upper cooler les dense layers intercept less energy than the lower denser, warmer layers; so the escape path is always favored.
And if you really want to believe that H2O is a greenhouse gas, since there never is dry air. Whence comes this nonsense that H2O needs CO2 to kick it into action; and once your accept H2O as a gHG all bets are off; because as the only condensing GHG, it is the only one that can form clouds, and then it can shut down incoming soalr energy big time.
Our quite mild Temperature range on earth from -90C to + 60 C, is regulated completely by the physical and chemical (bio too) properties of the H2O molecule.(in all its phases)
Re Infrared
It [my link to IR radiance of hot steel 100,000 times greater in IR than Visible light] is interesting re the figures for IR radiation from the Sun, which AGW promote and which seems to be accepted by many on the other side of the argument, to be around 50% IR, typical on this in the wiki page on Infrared.
On that wiki page is also that mid and far are often referred to as thermal, in contrast to near and short wave Infrared which are said to be reflective. I think that means the mid and far are then absorbed? Which AGW then says not much reaches the ground. Obviously we don’t feel warmth from the Sun.. And also, much is made of this being near infrared, which I say is cool, by mentioning it and not mentioning the mid and far.(because other standard sources say so, that heat energy begins in mid and is strongest in far.)
For example: http://www.emersonww.com/FAR_NearInfrared.htm
“Infrared:
This wavelength of light warms objects without warming the air between the source and the object (known as conversion).
This radiant heat can also be called Infrared Energy (IR). Do not confuse this with UV radiation (sunburn) or atomic radiation (nuclear) – see the diagram above for where these types of light fall on the spectrum. Infrared waves are not visible to human eyes but can be seen by special instruments that translate infrared into colors that are visible to our eyes. The best example is the sun (80% of the sun’s rays are infrared).
Our atmosphere allows infrared rays in the 7 to 14 micron range to safely reach the earth’s surface.
When warmed, the earth radiates infrared rays with its peak output at 10 microns.
The human body radiates infrared energy out through the skin at 3 to 50 microns, with most around 9.4 microns.”
So, two things here. First, the 80% of Sun’s radiance being in IR makes sense from the hot steel fact and yet contrary to our everyday experience of living in a world heated by the Sun, AGW says that IR is practically irrelevant to heating the Earth and ourselves, that the Earth is heated by Visible light and some Near Infrared, and the only Infrared that needs to be considered is that radiated back into the atmosphere from the Earth.
Second, this page also gives micron spread for the Infrared – .76-1.5 for near, 1.5-5.6 for middle and 5.6-1000 for far infrared.
Since the mid infrared is where it begins to carry heat energy, heat from IR is radiating directly into a greenhouse, and out again at night when no longer being radiated in by the sun. I’ve seen other applied science pages which give the beginning of opaque to IR at 5 and 6.
Actually, a third. AGW claim is that Infrared is mostly unable to get through our atmosphere, so therefore irrelevant to heating the Earth directly, but, if what is said above is saying that it is the shorter wave length infrared which gets reflected, then these are like I suppose, the blue colour which gets scattered. This it seems to me is what is meant by “Our atmosphere allows infrared waves in the 7 -14 micron range to safely reach the earth.”
So it appears that AGW has simply jettisoned all the mid and far infrared non-reflective IR from their energy budget diagrams and models, that Infrared which is absorbed by organic matter on earth.
[Sorry mods, I did check the first post, but missed that the slash and b were reversed.]
I give up. Don’t know what I’ve done wrong here.
Anyway, to counter the Domenic put down about medical sources cranky,
http://www.panmedicahealth.com/photobiomodulation.shtml
Scroll down to –
Low Level Laser Therapy Clinical Applications
NASA research further explains:
“Low-energy photon irradiation by light in the far-red to near-Ir spectral range with low-energy (LLLT) lasers or LED arrays has been found to modulate various biological process in cell culture and animal models. This phenomenon of photobiomodulation has been applied clinically in the treatment of soft tissue injuries and the acceleration of wound healing. etc.”
IR is deeply penetrating and short wave UV is not. I’m glad it’s this way around..
And neither Mikael nor Domenic have come up with anything to prove otherwise.
“”””” 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. The following table compares the peak absorption coefficients per molecule for several molecules.
CO2 1 E-19
H2O 1 E-18
O2 1 E-28
N2 1 E-28 “””””
Robert, rest assured that I DO know that even in the dryest of air, there is lots of H2O. And thanks for your actual numbers for some interesting places. I simply wanted to make a “Dry Air”, totally devoid of water, so that I could discuss the gh effects relating to just the CO2 by itself; and I agree with you that the N2,O2 line spectra emissions are negligible in the scheme of things.
Once one understands how CO2 in the N2/O2/Ar atmosphere acts, then one can re-insert the H2O or any other GHG and see that the same consequences still apply.
The point is that any small sample of air ( one cubic micron for example), is constantly radiating a thermal spectrum; and by “thermal spectrum” I mean a black body like spectrum that is a consequence solely of the Temperature of the sample.
That radiation would of course cool the sample; but the energy is constantly being replensihed by other energy input processes, either gHG absorption and thermalization or from latent heat or conduction.
So the air sample is at the Temperature it is at, because that is the Temperature at which its thermal radiation just equals the energy input from other sources.
In any case; thanks for your insights. If there was an app, for some geektoy or other, that could compute the spectrum of any species in any environment to the extent that QED makes that possible, I would consider buying such a geektoy. Sadly I don’t have access to some of the behind the pay wall programs; and also I have no confidence that they are even correct, since they never say what the circumstances of the derivation are.
It would appear that IR is selective in many ways. Apparently it’s warming up my insides but it won’t come out and tell me how warm they are. Either that or I’m about to succumb to hypothermia. My IR gun says my toes are 18C. I ‘d always thought that was the surface temperature. I guess I really am cold-hearted.
@ur momisugly Myrrh. About shorter wavelengths penetrating better. It is a general rule with plenty of variation. But consider the extremely short X-ray and gamma wavelengths and you have a couple of good examples.
Re Bolzmann – “NASA covered up for forty years proof that the greenhouse gas theory wa bogus.” “..NASA, proved there was no such thing as a greenhouse gas effect because the ‘blackbody’numbers supporting the theory didn’t add up in a 3-dimensional universe:”
http://sppiblog.org/tag/stefan-boltzmann-equations
Re the ‘missing longer wave IR absorbed by the atmosphere and not reaching earth’ of the AGW energy diagrams. Seems it is absorbed by water and carbon dioxide in the atmosphere so doesn’t get down to us except that re-radiated from this which is only part of its initial force as some gets re-radiated away from Earth.
Anyway, at around, don’t recall but offhand about .5 – 3or5% of the atmosphere is water vapour depending on local conditions, this can hardly stop the bulk of longwave IR from reaching the Earth. More nonsense then.
http://www.castlerock.wednet.edu/HS/stello/Astronomy/TEXT/CHAISSON/BG305/HTML/BG30503.HTM
It’s simply a fact that far IR penetrates deeply, its properties are well known in some science which uses this knowledge and it’s well known to some science that UV doesn’t penetrate. Anything can penetrate given enough force. But warmth from the Sun is indisputable to everyone’s common sense, we all know the feeling of being warmed up by the Sun. Go stand in the coldest spot you can tolerate and then go stand in the sunlight, IR isn’t called Heat Energy for nothing.
To say that shorter wave lengths penetrating better is a general rule subject to variation is not good enough since you claim these penetrate deeper than IR. Prove that in real life. You haven’t disproved Herschel.
Re George E. Smith, February 18, 2011 at 12:36 pm, we disagree on much of what you say. However, I do agree with “most” of your description of how more radiation goes toward space because the absorption lines get narrower. The problem with your description is that you ignore the clouds. Remember, they cover about 1/2 of the planet. Because clouds are blackbody radiators with no distinct spectral lines, there are no line widths to change with temperature and pressure. As a result, their downward radiation is greater than upward since the bottoms are warmer than the tops.
Also, please stop suggesting that O2, N2, and Ar are blackbody emitters. At the temperatures and frequencies of interest, they simply are not. On the other hand, clouds, aerosols, and dust are.
I am currently working on an app that works with the spectra of just water vapor and CO2. If you would like to be an alpha tester, contact me via my web page.
Michael H. Anderson
Oops: Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995
http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html#ixzz1EKbIpSQb
Why has this non-issue not simply dried up and died? Why isn’t this article known to every English-speaking man, woman, and child on the planet?
There are lots of things people ought to know, but you can’t know about a subject unless you follow that subject. Is the fact you cite news to you? It’s about a year old, and Richard Lindzen was saying essentially the same thing well before then.
Robert Clemenzi says:
February 18, 2011 at 10:48 pm
I am currently working on an app that works with the spectra of just water vapor and CO2. If you would like to be an alpha tester, contact me via my web page.
——————-
I tried out the Stefan-B convertor on your webpage.
One issue that should be relevant to this topic is that Earth is a rotating sphere.
During the height of the day at the equator, 1361 joules/m2/second (less 30% Albedo) is coming in from the Sun but the surface temperature only increases as if 0.0017 joules/m2/second is absorbed (or impacts the temperature at 2 metres). The extra 959.9983 joules/m2/second flows away from the surface effectively almost as fast as the energy is coming in.
Your calculator says surface temperatures should increase to 87C.
At nght, virtually no radiation is coming in (and the upwelling less downwelling radiation) says the surface should be losing about 100 joules/m2/second but it actually only loses 0.001 joules/m2/second.
This is the real-world now versus the theoritical.
The daily radiation budget fluctuates by huge numbers (+/- 1060 watt/m2) but the surface temperature only changes by +/- 5.0C on average or +/- 27 watts/m2.
One SurfRad station measurements over a 24 hour period.
http://img140.imageshack.us/img140/4109/tablemountainall.png
http://img12.imageshack.us/img12/3225/tablemountainnets.png
Something else is going on in the real world.
There is indeed, a LOT of that ‘something else’ that goes on in the real world.
That is why I have been repeatedly posting here that most assumptions made by climate experts, and others, regarding the ‘greenhouse effect’ and thermal radiation are completely wrong.
to Robert Clemenzi
For example, on your website you wrote: “On the Moon (no atmosphere and 28 day rotation), the maximum temperature is within a few degrees of what is predicted. However, on the dark side the minimum temperature is never reached … it is not even close. This indicates that objects heat up faster than they cool down. This asymmetry means that Stefan’s law can be used to predict maximum temperatures, but is fairly worthless at computing the minimum temperature of a rotating body. It also means that using this equation to compute the expected temperature from the average energy will always give the wrong results.”
The problem is not Stefan’s law, the problem is the thermal mass of the target area and the thermal conduction within the target area material.
Here’s an experiment for you: take a piece of styrofoam and aim a radiant heat source at it while also aiming an IR thermometer at it. You will see the surface IR temperature immediately jump to an equilibrium value. Now, remove the radiant heat source, and you will see the IR temperature immediately DROP to the local radiational ambient temperature, virtually no time delay.
The reason, of course is that styrofoam lacks thermal mass, so there is no thermal conduction to keep supplying the surface with additional heat once you remove the radiant source.
Stefan’s law will hold perfectly in this situation.
RE: Mikael Cronholm says:
RE: Saunas
(Sorry for going off topic!)
A pleasure reading. . . My father from Finland, me Ma from Ireland. According to Dad, neither could speak ‘English’ when they here in Canada. The clothing ‘optional’ thing even when the nieghbours were over for a steam never impressed Mom much. In the beginning (60’s) Mom saw as it some kind of Hippy-freak thing as opposed to a cultural norm (and would have no part of it!). Fifty years on her opinion hasn’t changed much. Dad on the other hand, never saw the point in ‘High Tea’ . . .
Now back to the tuff stuff. . . sigh . . .
I’m trying hard to simplify things in a way that will give me at least a chance to remember salient points raised here.
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?
-Barn
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”
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.
My last word on the opacity of glass.
As I have made perfectly clear, the claim that glass is opaque to IR is a fallacy which leaves one with the false impression that glass presents a barrier to the passage of IR. Pure and simple. At no point have I claimed, as Mikael has implied that IR is radiated through the molecules in the solid glass. Simply I maintain that glass does not present a barrier to the escaping IR energy from inside a greenhouse any more than a gas does in the open atmosphere.
Whether or not this achieved via conduction through 4 mm of solid glass via conduction at a rate of 6.7 billion collisions per second, to the colder exterior surface of a greenhouses glass walls, is of no consequence. The effect is the same. The IR energy is not trapped, the energy instantaneously exits through the glass all the same. The likelihood that this energy will be returned to the interior and become “trapped”, as in the implication by the use of the phrase “opaque to IR” is reduced to at least improbable by the second law of thermodynamics. Whether you call this transmission or absorption and re-emission is pure semantics for the following reason. To absorb energy, the glass, being a solid, must be cooler that the ambient surroundings. To emit energy it must be warmer. These are definite conditions. If the glass is at equilibrium with the environment we are left with pure probabilities. Probabilities being the nature of not just light but all natural phenomena. So we are left with the probability that an infra-red photon will be absorbed and re-emitted by the glass, a probability that it may be absorbed and reflected or re-emitted back inside. But the fact that the greenhouse interior is warmer changes a probability into a near certainty and ensures that the energy flows out.
The nature of glass with it’s transparent double sided 2D surfaces, allows for all sorts of fun and games for the sophists. The only way to show that the phrase “opaque to IR” is a meaningless, deceptive use of the very broad, unspecific adjective/noun which is meant to describe visible not invisible phenomena, is to enclose an IR sensor behind a piece of glass (with the glass at equilibrium with the ambient air temp) filtered to detect between 8-14 µm, which is the usual spec for such devices and see if it picks up any IR. This I have done many times and find no barrier effect from glass that blocks the passage of IR. This whether you like it or not is empirical evidence that glass does not block IR. It also shows that transmission of IR is not required in order for IR energy to traverse substances with relative ease. That is not controversial physics, it is common knowledge.
As I have made clear to both Ken and Mikael, the use of the term “opaque to IR” is not only meaningless, it is pure sophistry. It gives the false impression that IR is trapped by glass in a greenhouse and that this effect is similar to the effect of “greenhouse gasses” in the open atmosphere.
When the public realises that whole greenhouse effect hypothesis hangs on such flimsy, ambiguous use of such terms as ““opaque to IR”” and such brazen underhandedness is at the very root of AGW fraud,
PREDATOR becomes PRAY.
Over and OUT.
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. It is heat radiation from a much warmer sky that keeps them at a “warm” 190K or so. In fact, at many places over land, the morning surface temperature is lower than the temperature of the air above it.
Mountain tops actually receive slightly more energy from the sun than the land at sea level. Yet, they are colder because the air at that level is colder.
Where I live, in the spring it sometimes snows one week, will be in the 70F’s the next week, and then snow yet another week later. During this period, the amount of energy from the Sun increases each day (remember, this is during the spring).
The difference between Stefan’s equation and what is observed is the definition of the greenhouse effect.
Has any of our posters read thru this?:
Professor Claes Johnson Dissects the Failed Greenhouse Gas Theory
Ken Coffman (KLC) as above interviews Dr. Claes Johnson (CJ) Professor of Applied Mathematics at the Royal Institute of Technology in Stockholm.
I found it @John O’Sullivan’s blog:
“Top Swedish math professor, Claes Johnson, who mathematically refuted the greenhouse gas theory of man-made global warming, was banned by his university employers from teaching his expert analyses to students. Despite the gag on his academic freedom, a brave Johnson spoke candidly to Ken Coffman on the biggest controversy now raging in climate science.”
The rest here: http://johnosullivan.livejournal.com/
It appears the AGW theory is missing more than just some heat . . .
-Barn