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Post by steve on Oct 17, 2009 13:51:37 GMT
If you look again at what I said, I put "window" in quotes, and pointed out that the water vapour did have significant emissivity within the window. So "window" is a relative statement - I didn't claim it was transparent.
The measurements of CO2 emissivity were derived from tables. I assume the tables were obtained from experimental evidence. Unless there is evidence to the contrary I'm going to assume that the figures are roughly correct.
So perhaps we have significant water emissions from the ocean and from the 50mm or so of precipitable water vapour in the atmosphere. Most of the water vapour is below 5km. Above 5km we still have the equivalent of between 1 and 2 metre layer of CO2 gas that can absorb the radiation from below, and very little water vapour - equivalent to only a millimetre or so of water, and dropping off quickly with increasing height.
Also you cannot ignore the fact that we *do* have CO2, and it will emit in its own bands because it is excited by collision far more often than it is excited by absorbing a photon. So if you like, the ocean emissions warm the water vapour via radiation. The water vapour passes energy to the atmosphere via collisions. The CO2 is warmed along with the rest of the atmosphere and emits at 15 microns.
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Post by steve on Oct 17, 2009 14:09:56 GMT
Icefisher started by saying there was no energy emitted, then energy *was* emitted at different frequencies, *then* energy was emitted but it was "not significant" which is like saying "I'm a bit pregnant". There were no two "then"s. Its entirely what you imagined and you are jerk for not looking more carefully before impugning somebody with something they did not say. I replied directly: "Good catch! I should have said "no significant energy"." Hammer is the one making the case for the IR window and the thinning atmosphere in the regions where CO2 dominates may well turn what is significant when mixed with water vapor into insignificant when mixed with only CO2. Though I agree that for at least 2 seconds I went as stupid as you for assuming that N2 and O2 have no significant emission importance in the atmosphere. I agree that while sometimes its practical to assume absolutes, its pretty dangerous and stupid to jump to global systems and into quadrillions of tons of matter with experiments on pounds of matter. But that seems to be your stock in trade as you play top sycophant for the warmistas. However, the 2 seconds ended abruptly because ignorance is curable but stupidity is forever. Sorry, radiant said I was wrong for suggesting that in the context "not significant" was unscientific. I wasn't trying to have a go at you, but radiant regularly accuses me of saying unsupportable things (even when I haven't said them) in quite a challenging way. But for the record, I realise that you were interpreting someone else, and I thought there were two "thens" first when challenged about the "CO2 funnel" by glc, and then when challenged about Kirchoffs theorem.
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Post by radiant on Oct 17, 2009 16:14:23 GMT
If you look again at what I said, I put "window" in quotes, and pointed out that the water vapour did have significant emissivity within the window. So "window" is a relative statement - I didn't claim it was transparent. The measurements of CO2 emissivity were derived from tables. I assume the tables were obtained from experimental evidence. Unless there is evidence to the contrary I'm going to assume that the figures are roughly correct. So perhaps we have significant water emissions from the ocean and from the 50mm or so of precipitable water vapour in the atmosphere. Most of the water vapour is below 5km. Above 5km we still have the equivalent of between 1 and 2 metre layer of CO2 gas that can absorb the radiation from below, and very little water vapour - equivalent to only a millimetre or so of water, and dropping off quickly with increasing height. Also you cannot ignore the fact that we *do* have CO2, and it will emit in its own bands because it is excited by collision far more often than it is excited by absorbing a photon. So if you like, the ocean emissions warm the water vapour via radiation. The water vapour passes energy to the atmosphere via collisions. The CO2 is warmed along with the rest of the atmosphere and emits at 15 microns. Tyndall said: Nature is full of anomalies which no forsight can predict, and which experimentation alone can reveal.If we apply a Tyndallisation to what we know so far we get: 1. From C02s spectra we can learn what frequency will be absorbed by water and find the depth of water to absorb C02. It will be about one tenth of 1mm of precipital water or 0.1mm PWV. 2. From what we have observed of waters spectrum there is no atmospheric window on earth because in the regions of ir absorption that concern us water has to be less present than it is found anywhere in the atmosphere on earth. 3. Astronomical studies have shown that the lowest water concentration on earth is at Ridge 'A' in Antarctica where there is a minimum of 0.6mm of precipital water which is 3 times better than the South Pole itself 159.226.168.50/domea/Academic/FrontCosmo/Talk_in_PDF/Saunders.beijing2.pdf4. Nightcooling studies show that water is the main cause of the downdwelling atmospheric radiation in antarctica but at this point in time the water concentration for those studies is unknown to me 5. C02 has no influence or an insignificant influence in the lower atmosphere anywhere on earth, unless C02 emission lines are able to pass thru waters lines when water is present in very small quantities. 6. The height in the atmosphere where water becomes insignificant can be reasoned to be at heights beyond the tropopause. No doubt there is science on precipital water vapour content in the atmosphere to inform us of the approximate altitude. 7 A.. C02 absorbs IR radiation where water is not present high in the atmosphere. B.. C02 will be warmed by this radiation and be cooled by the surrounding mass of the atmosphere to which it will transfer heat. C.. This part of the atmosphere will be warmed and C02 will then emit back to earth in a narrow band of emissions that will be entirely absorbed by water at a high, and approximately known altitude, of somewhere in the higher troposphere. Water will be warmed and transmit at all frequencies. A fraction of the downdwelling radiation from the higher atmosphere C02 will be sent back to the C02. An infintesimal amount of the downdwelling radiation from the warmed water might be capable of reaching further down into the atmosphere from the emission of water but this seems very unlikely given waters extraordinary absorptive powers 6. None of the upper atmosphere green house gases will have any influence upon the climate of earth because a truelly insignificant amount of their radiation will get anywhere beyond the high troposphere. 7. The freezing cold high tropopause with a tiny amount of water in it has a tremendous ability to protect the climate of earth from any long wave ir influences that should ever be experienced in space around Earth. All of the above can be confirmed or falsified by experimentation or by knowledge of known spectroscopic principals gathered via experimentation.
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Post by steve on Oct 17, 2009 17:21:04 GMT
If a bit more radiation from the upper atmosphere goes down, it helps keep the layer below a bit warmer. This lower layer then radiates a bit more - both up and down, so keeps the layer below it a bit warmer. etc. etc. etc. down to the surface.
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Post by icefisher on Oct 17, 2009 17:30:38 GMT
So perhaps we have significant water emissions from the ocean and from the 50mm or so of precipitable water vapour in the atmosphere. Most of the water vapour is below 5km. Surely there must be a spectra analysis taken from 5km? Is the funnel substantially missing? Seems you put a lot of stock in how high in the atmosphere water vapor exists. Why not put some stock then in how high CO2 band spectra is rising? Such an approach would not make the case as it would still have to deal with the heat in that region of the atmosphere and the intensity of that radiation from the atmosphere itself. . . .but at least maybe you could actually provide some evidence that we should be concerned with the altitude limits of water vapor. As it is you seem to think its important but you provide zero information about it. Also you cannot ignore the fact that we *do* have CO2, and it will emit in its own bands because it is excited by collision far more often than it is excited by absorbing a photon. So if you like, the ocean emissions warm the water vapour via radiation. The water vapour passes energy to the atmosphere via collisions. The CO2 is warmed along with the rest of the atmosphere and emits at 15 microns. This seems to totally muck up what my take on IR absorbance and emissions are all about. As I understand it warmed bodies emit at some factor of their temperature in accordance with a BB curve. But I had not heard of a molecule taking heat energy and converting it to vibrational energy and emitting it at certain frequencies, implying that CO2 cools much faster than other non-GHG. Your description of CO2 would seem to imply that CO2 is a net cooling vehicle for the atmosphere by getting the IR in essence airborne faster.
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Post by radiant on Oct 17, 2009 17:35:39 GMT
If a bit more radiation from the upper atmosphere goes down, it helps keep the layer below a bit warmer. This lower layer then radiates a bit more - both up and down, so keeps the layer below it a bit warmer. etc. etc. etc. down to the surface. A fraction comes down to an area where it is freezing cold where emmissions from this area will be absorbed in about 1mm of PWV where the full range of frequencies of water will emitt in all directions. There is no ability of the warmth to penetrate downwards more than a tiny distance before half gets sent back up to be absorbed higher up from where it was first absorbed by water where there is then no water left to absorb the emissions once reemitted. Only a fraction of the upwards escaping emissions will be absorbed. All of the downwards pointing emmissions are absorbed in a tiny distance once absorptions begin occuring in the troposphere. But the issue should be settled by experimentation rather than word games
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Post by steve on Oct 19, 2009 9:26:20 GMT
We've all pointed out the difficulty of finding such observations. Just to be clear though, the "funnel" is a function of observing CO2 against a backdrop of warmth below. CO2 is actually emitting radiation in this region of the spectrum, it is just that less of the radiation from below is getting through all the CO2.
There does, on the other hand, seem to be an aversion to accepting the fact that observations indicate that the "CO2 funnel" does exist in favour some speculation about the amount of water vapour in the atmosphere.
The effectiveness of water vapour in absorbing CO2 has been stated here, and I have asked for further evidence. I have had a quick look for data on water vapour above 5km and I don't think it is very much - possibly 2-3 mm in the tropics - obviously much much less a bit higher up or at higher latitudes. I've pointed out that half the CO2 is above 5km in height. And there is still a third of CO2 above 9km in height (top of Everest).
The simple description of the "greenhouse effect" envisages radiation being emitted from the ground and being "trapped" by greenhouse gases. Certain sceptics have built a fallacy on this faulty illustration by pointing out that adding more CO2 doesn't much effect the amount of the radiation emitted from the ground and absorbed in the atmosphere (the saturation argument).
The reality is that in any one moment the ground and the whole of the atmosphere is absorbing and emitting radiation, and that (vastly more often than absorption and emission takes place) molecular collisions take place to exchange energy.
So the effect of an individual molecule depends on where it is. A greenhouse gas molecule high up in the atmosphere will emit half of its energy upwards, and much of it will go into space, so cooling the atmosphere. Emissions of a molecule that is deeper in the atmosphere will have an exponentially increasing chance of being reabsorbed before reaching space. Adding more greenhouse gases raises the layer at which a given percentage of emissions escapes to space.
Since higher layers are cooler, these higher layers emit less energy to space until they are warmed up by the net energy being absorbed by the earth.
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Post by radiant on Oct 19, 2009 10:48:40 GMT
Ozone is present in the stratosphere in concentrations of 2-8ppm it is a weakly absorbing gas compared to water which is present about 3-6ppm in the stratosphere and yet even so ozone is a powerful absorber where it absorbs
Tyndall said Ozone absorbed about 8000 units to nitrogens 1 and the 700 of C02. Water was far away in excess of Ozone.
C02 is claimed to be well mixed in the atmosphere but some studies say the mesosphere is layered
At STP
C02 is heaviest at 1.98 or 1.5 times that of air Argon is 1.78 Oxygen is 1.308 air is 1.27 nitrogen is 1.25 Oxygen is 1.308 water vapour is 0.8
Helium which has a density of 0.178 and is a product of radioactive decay escapes to space along with hydrogen.
Diffusion of gases depends on the speed at which atoms and molecules with energy can travel and less dense atoms and molecules travel faster. Diffusion of gases therefore tends to mix gases and yet ultimately are the cause of their ability to separate from other gases.
At this point in time the mesosphere is not well understood.
Even at STP ice fairly rapidly sublimates into dryish air so we can reason that water vapour very high in the atmosphere in lower concentrations will be in the form of water vapour.
The mesosphere is very poorly understood but it seems well known there is a flow of moist air moving from the summer hemisphere pole to the winter hemisphere pole in the mesosphere
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Post by steve on Oct 19, 2009 10:58:28 GMT
From quite a bit of Googling, absorption by water vapour does not seem to be the same as absorption by water. So the high emissivity/absorptivity of water does not appear to translate to a corresponding high absorptivity of water vapour.
But it is a highly complex subject which I can't properly understand. Based on some reading (Google "water vapour absorption" and start clicking) there *is* a "window" to absorption, information which seems to be a key point to this discussion.
Eg. from the densely written book "Atmospheric radiation: theoretical basis" By Richard M. Goody, Y. L. Yung written in 1964 and revised in 1995:
As the rotation bands are stated as being at longer wavelength, this says to me that a) 10mm of precipitable water would only absorb 10% of some radiation, and that b) radiation transmission of only 10% for 10mm of water is seen in a window for wavelengths longer than 6.3 microns up to I don't know - CO2 is at 15 microns.
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Post by steve on Oct 19, 2009 11:02:15 GMT
The greenhouse effect is largely discussed as a troposphere stratosphere phenomenon. CO2 is well mixed here.
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Post by radiant on Oct 19, 2009 11:21:13 GMT
Most internet sources of waters ability to transmit Ir radiation are misleading as i have already shown Tyndall said he could detect no differences between water ice and vapour Tyndalls results must be saying something about the real world From the graph that says water and water vapour absorb very differently we see: Which at first appearance appears exstremely different to this: But first graphs entire range is from only either side of the strongest part of the water absorption from 2.5 to 3.6 micron on the graph of water only So that it only includes this part: Which means that water vapour probably absorbs this frequency in 1mm of precipitated water equivalent
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Post by radiant on Oct 19, 2009 11:29:30 GMT
The greenhouse effect is largely discussed as a troposphere stratosphere phenomenon. CO2 is well mixed here. Which is just a discussion of something that is incorrect if C02 absorption would be absorbed by water anyway higher in the atmosphere. Wiki says the gases are stratisfied from the mesopause upwards. The whole thing with C02 is theoretical. Models have major problems: Even water is poorly understood as an absorber in terms of lines it absorbs by the greatest experts of water in the whole world. Most people dont seem to be able to grasp the enormous ability of water to absorb IR radiations and they appear to assume that low concentrations make them irrelevant.
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Post by steve on Oct 19, 2009 11:49:45 GMT
I didn't post an "internet source" I posted information from a book about atmospheric radiation.
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Post by radiant on Oct 19, 2009 11:58:45 GMT
I didn't post an "internet source" I posted information from a book about atmospheric radiation. You posted a book dealing with theorectical aspects. I posted on what is actually measured and showed how most people are producing misleading information
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Post by steve on Oct 19, 2009 15:44:12 GMT
Radiant, you appear to have based your posts on the belief that the liquid water absorption profile is a good reflection of the absorption of water vapour. Here are two more papers of observational evidence for the water vapour "window" in the 8-13 micron region that suggests that this assumption is wrong: The Quarterly Journal of the Royal Meteorological Society Volume 99 Issue 421 A study of the continuum absorption within the 8-13 m atmospheric window A. C. L. Lee The above says significant exchange of radiatio occurs near the surface which would be impossible if the water vapour absorbed all the radiation in less than a mm of equivalent amount of water. Certainly, remote sensing (presumably from space) would be impossible. The next study was observations over a distance of 1-1.5km in the atmosphere over the same spectral region. Other than it being further evidence that an atmosphere with a significant amount of water vapour is not opaque to radiation in the IR region, the paper is not that relevant to the discussion. Measurements of Lorentz air-broadening coefficients and relative intensities in the H216O pure rotational and v2 bands from long horizontal path atmospheric spectra Curtis P. Rinsland, Aaron Goldman, Mary Ann H. Smith, and V. Malathy Devi Applied Optics, Vol. 30, Issue 12, pp. 1427-1438 doi:10.1364/AO.30.001427 www.opticsinfobase.org/ao/abstract.cfm?uri=ao-30-12-1427which studies the spectral region:
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