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Post by FurryCatHerder on Apr 2, 2009 22:16:20 GMT
See section 3.4.2 Water Vapour in AR4 See "Outside My Window". Or better still, look at a rain gauge. It stills rains. The rain hasn't stopped. The difference between CO2 and H2O is that when there is too much H2O in the atmosphere, it falls out as "rain". This is not at all the case for CO2.
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Post by jimg on Apr 2, 2009 22:50:29 GMT
Socold: You still haven't answered this queston: Do you believe that atmospheric water vapor is at saturation? Furry, are you suggesting that rain is a reduction of the overall water vapor in the atmosphere? That it is continually declining? If not the fact that it is raining outside you home is irrelevant and has no basis comparison to CO2. Yes water vapor leaves the atmosphere, but it is also continuously being replenished. In addtion, a warmer planet means that the atmosphere can hold more water vapor. (ie. relative humidity.) So if the atmosphere is holding more water, more greenhouse effect from water vapor. Even though it might have exceeded saturation in some areas, doesn't mean that it has in others. (ie, relative humidity, as temperature decreases, then saturation temp decreases and you have a super-saturated fluid) {edit: revised paragraph} Just in case anyone wishes to flame here's a decent explanation: en.wikipedia.org/wiki/Supersaturation
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Post by socold on Apr 3, 2009 0:35:10 GMT
Socold: You still haven't answered this queston: Do you believe that atmospheric water vapor is at saturation? No it's not and I guess you are right, in areas where it isn't saturated adding it (at a constant replenishment) can maintain higher levels than if it isn't being added.
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Post by icefisher on Apr 3, 2009 2:49:07 GMT
Nope. The AGW hypothesis was born in 1896 and has survived numerous ups and downs in temperature. You mean 112 years and it still hasn't paid off? LOL! But, its a virtual baby compared to get rich quick schemes! "There is a new one being born everyday" is a phrase that has truth to it.
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Post by jimg on Apr 3, 2009 3:02:42 GMT
Thanks socold. My issue with greenhouse/agw theory has not been that the process does not exist, but one of quantification and forcing/feedback coefficients.
From what I think I understand of the models, water vapor and clouds are considered to essentially be at or near constants.
If water vapor has increased as CO2 has increased then the amount of warming that has been ascribed to CO2 is not as big.
(I would actually even feel a little better about the AGW theory if all GHG's that man introduces into the environment were of issue. But that clearly has not been the case.)
The second issue is with very long term natural variability. The issue of the unkown unkowns.
To suggest that we have the necessary and sufficient knowledge at this time to make 100 year forecasts to me seems a bit naive.
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Post by kiwistonewall on Apr 3, 2009 3:16:20 GMT
I've never said that the greenhouse effect doesn't exist either.
Can socold state which of these is false:
1. A Planet with an atmosphere (no matter what the composition) will have a greenhouse effect: True or false? (I say true)
2. All bodies of gas at thermal equilibrium will radiate light at the appropriate black body curve: True or false? (I say true)
3. Heat radiation can only flow from warm to cold (In the absence of a heat pump) True or false? (I say true)
I know he has disagreed with some or all of these in the past.
There is a huge amount of confusion in this whole area. The biggest is confusing black body radiation with spectral effects (the absorption peaks when a beam of light passes through a gas).
There is NO relationship between spectral absorbance at certain frequencies from a beam of energy passing through a gas, and the thermodynamics of radiation. In one case, you are looking at what happens to a beam passing through a gas, and what energies are absorbed. In the other, you are looking at bulk bodies (surfaces, or volumes of gas) radiating energy distributions.
The maths of absorption spectroscopy, and the thermodynamics of heat transfer are too entirely different areas, each with their own mathematics.
Note, and note well: All thermodynamic transfer of radiation has NO MATHEMATICAL RELATIONSHIP with quantities of any gas that absorbs/emits spectroscopically at any quantum frequency. The only way is to talk about the process. There is no mathematically way to represent it. It is entirely fictitious.
Take two bodies of gas in thermal equilibrium, one containing lots of greenhouse gas, the other containing none. Assume (for arguments sake), that they are not mixing at the boundary. (You can actually do this in a real world experiment - you just need to separate the gases with a filter transparent to the radiation. NaCl is often used in IR spectroscopy) What is happening to radiation moving between the two gases? Shouldn't the "more efficient" greenhouse gas absorb more of the radiation entering from the less efficient gas? And therefore warm up? This is exactly what they are implying.
It doesn't happen. The (false) greenhouse effect doesn't effect the mathematics of radiative transfer(the true greenhouse effect).
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Post by kiwistonewall on Apr 3, 2009 5:18:39 GMT
Socold, you are coming around, and being forced to be a bit more scientific than the IPCC. I'd like to apologise, as I had assumed your view of the Greenhouse effect was that of the IPCC: ipcc-wg1.ucar.edu/wg1/FAQ/wg1_faq-1.3.html"Much of this thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated back to Earth. This is called the greenhouse effect. " The obvious import of this statement - what joe public will understand by this, is that heat is transmitted back to Earth. This is nonsense, as I have pointed out in the past. The "greenhouse effect", which is only a small part of the atmospheric processes, is simply the delay in radiation reaching space caused by the black body absorption and emission of radiation following normal thermodynamic heat transfer. The atmosphere CAN be warmer that the Earth, and will radiate back to the Earth across the entire bb spectrum of the temperature. This happens at night. It is related to temperature differences, and not the composition of the gases in the atmosphere. The net average (over a year, and day & night) is for outward radiation only. There is no mathematical formula that can describe this nonsensical physics.
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Post by jimg on Apr 3, 2009 5:32:58 GMT
Kiwi: I might take issue with #3, but it might be a case of somantics.
Heat can only be transferred from hot to cold. This is the action of kinetic energy being transferred from one molecule to the other and is not electromagnetic radiation.
Energy in the form of electromagnetic radiation will be given off by all substances in accordance with Planck's law. This radiation is not bound by temperature differences and will be emitted in all directions.
GHG's may capture outgoing IR and re-emit a photon of lesser or equal value. The greenhouse effect is a limiting of escaping radiation, EM, not thermal heat transfer.
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Post by steve on Apr 3, 2009 10:18:29 GMT
I've never said that the greenhouse effect doesn't exist either. Can socold state which of these is false: 1. A Planet with an atmosphere (no matter what the composition) will have a greenhouse effect: True or false? (I say true) True. But if the gases in the atmosphere do not have spectral lines in the range of radiation emitted by the surface then the effect will be weak. And if the atmosphere is thin the effect will be weak. [/quote]2. All bodies of gas at thermal equilibrium will radiate light at the appropriate black body curve: True or false? (I say true)[/quote] This is false. Please show a spectrum of emission from the earth's atmosphere that proves this point. You are mixing up terms - heat and radiation. Radiation is an easier concept to understand. Radiation will be emitted by a warm object in all directions. Radiation from a warm object will be emitted towards an even warmer object. Heat is a term usually used to describe a net flow of energy. A warm and hot object will send radiation to each other. But the hot object will send more radiation to the warm object. So the net flow of energy will be towards the warm object: heat will flow from the hot to the warm. Stephan-Boltzmann's equation includes a term for emissivity. CO2 has high emissivity at 15 microns. O2 has high emissivity at 60GHz. So the spectroscopy of materials is included in the equations for radiation. By the way I agree with pretty much everything I read in Roy Spencer's post, and I've made nearly all of the same points myself. If, Kiwistonewall, you are going to continue confusing heat with radiation, grey body with black body and real greenhouses with the so-called "greenhouse effect", I'm reserving my right to reply with just this link: www.drroyspencer.com/2009/04/in-defense-of-the-greenhouse-effect/(Does the fact that I brought up Spencer and Lindzen in my defence yesterday make me psychic to internet transmissions?)
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Post by gridley on Apr 3, 2009 14:38:14 GMT
Socold, I'll try this one more time. Yes or no, do you believe the variable distribution of CO2 in the atmosphere will effect the total rate of heat transfer through the atmosphere? Yes or no, do you accept the relevance of the electrical analogue for analysis of this effect? FYI, your link didn't work for me, though I'm certainly not going to claim CO2 is the only factor at play! What I'm trying to do here is approach this problem from the AGW point of view: that CO2 is the dominant factor. If you don't believe that is the case on a short-term basis, what is your justification for dismissing the long-term effects of these factors that can overwhelm CO2 in the short term so easily?
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Post by gridley on Apr 3, 2009 14:58:21 GMT
Steve, thank you for the link to that site - looking at a few pages it appears to be at least heading in the direction of what I'm looking for. The formula you posted looks familiar, but I can't recall the source. Do you have it handy? My concern here is that in an electrical analogue model, an uneven distribution of resistance results in a higher current (i.e. heat) flow than a constant distribution, so if the GCMs assume uniform distribution at average levels when non-uniform distribution is the actual case, we will see less warming than the GCMs predict, since more heat will be transferred. So I'm simultaneously trying to determine how much effect the distribution will have, and how well the GCMs treat the distribution. If the electrical analogue is invalid here or is already well included, I can move on. If, however, it is valid and is not included, than the models would fail thermo 101 (heck, thermo 100), which would say disturbing things about the competency of the people who wrote them, and would make "tweaking" them to become reliable predictors impossible (a fundamental change would have to be made). I'm not that bothered about the term "well-mixed". What's important to me is that we know that an average 10% increase in CO2 at Mauna Loa would probably equate to an average of 10% increase at, say, sea level, 5km up and 10km up, in Iceland, Antarctica and the top of Kilimanjaro to name 3 places at random. This is different from, for example, water vapour where levels of water vapour drop rapidly with height, which is important when calculating the greenhouse. Had to search a bit for the "electrical analogue". In principle an area with lower than average greenhouse gases will "let out" more heat than an area with higher than average levels. The average amount of heat that needs to be let out is 235 Watts per metre squared. The change induced by CO2 is approximately 5.35 ln(C/Corig) where Corig is 280 parts per million. So current levels of 380ppm would cut the outgoing radiation by 1.6 Watts per metre squared. That's some info for you to play with the figures to see what effect variability might have, though variability in the vertical would also be relevant. This site seems to have a lot about CO2 measuring: www.esrl.noaa.gov/gmd/ccgg/carbontracker/index.htmlPerhaps you could download some of the Carbon Tracker output and calculate the forcing variability from it.
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Post by steve on Apr 3, 2009 16:22:09 GMT
The equation is from here: www.agu.org/journals/gl/v025/i014/98GL01908/GEOPHYSICAL RESEARCH LETTERS, VOL. 25, NO. 14, PAGES 2715–2718, 1998 New Estimates of Radiative Forcing Due to Well Mixed Greenhouse Gases Gunnar Myhre et al Models work as follows. Models are constructed with the physics as known, but they are tuned within the uncertainties of the observations to produce a stable evolution. ie. such that a model that is run for 20 years with constant CO2, constant solar etc. will produce a stable climate that approximates to earth's climate. In other words, a control experiment is created. Model are then run again with a perturbation such as a gradual increase in CO2, or a volcano or a change in the solar constant to see what would happen. The theory is that if the "electric insulation analogue" effect were important then it would be approximately equally important in the control experiment as in the perturbation experiment with CO2 rising. So if you were to modify the CO2 in the control experiment to match the real variability of CO2, and if you were to do the same in the perturbation run, then the perturbation run would diverge the same amount from the control run because the variability was similar. Since CO2 is quite a stable gas, then this sounds reasonable to me. If, for example, we were to consider ozone though (which is another greenhouse gas), ozone is an unstable gas and is created and destroyed in different parts of the atmosphere in different ways. Furthermore, as the climate warms due to greenhouse gases and as cities grow, near surface ozone levels rise. But the converse effect of greenhouse gases is that the stratosphere cools, and this reduces amounts of ozone there. The reduced stratospheric ozone lets through more UV which means that the stratospere cools more, and reduces ozone a bit more. So it would be a less safe assumption to assume ozone were always well mixed. Indeed many of the models separately model the effects of ozone creation and destruction. Steve, thank you for the link to that site - looking at a few pages it appears to be at least heading in the direction of what I'm looking for. The formula you posted looks familiar, but I can't recall the source. Do you have it handy? My concern here is that in an electrical analogue model, an uneven distribution of resistance results in a higher current (i.e. heat) flow than a constant distribution, so if the GCMs assume uniform distribution at average levels when non-uniform distribution is the actual case, we will see less warming than the GCMs predict, since more heat will be transferred. So I'm simultaneously trying to determine how much effect the distribution will have, and how well the GCMs treat the distribution. If the electrical analogue is invalid here or is already well included, I can move on. If, however, it is valid and is not included, than the models would fail thermo 101 (heck, thermo 100), which would say disturbing things about the competency of the people who wrote them, and would make "tweaking" them to become reliable predictors impossible (a fundamental change would have to be made). I'm not that bothered about the term "well-mixed". What's important to me is that we know that an average 10% increase in CO2 at Mauna Loa would probably equate to an average of 10% increase at, say, sea level, 5km up and 10km up, in Iceland, Antarctica and the top of Kilimanjaro to name 3 places at random. This is different from, for example, water vapour where levels of water vapour drop rapidly with height, which is important when calculating the greenhouse. Had to search a bit for the "electrical analogue". In principle an area with lower than average greenhouse gases will "let out" more heat than an area with higher than average levels. The average amount of heat that needs to be let out is 235 Watts per metre squared. The change induced by CO2 is approximately 5.35 ln(C/Corig) where Corig is 280 parts per million. So current levels of 380ppm would cut the outgoing radiation by 1.6 Watts per metre squared. That's some info for you to play with the figures to see what effect variability might have, though variability in the vertical would also be relevant. This site seems to have a lot about CO2 measuring: www.esrl.noaa.gov/gmd/ccgg/carbontracker/index.htmlPerhaps you could download some of the Carbon Tracker output and calculate the forcing variability from it.
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Post by trbixler on Apr 3, 2009 19:23:53 GMT
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Post by socold on Apr 3, 2009 19:54:42 GMT
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Post by socold on Apr 3, 2009 20:03:53 GMT
Socold, I'll try this one more time. Yes or no, do you believe the variable distribution of CO2 in the atmosphere will effect the total rate of heat transfer through the atmosphere? Yes or no Yes I don't know what that is. The AGW point of view is that co2 is the dominant factor over decades on a global scale because that's how long it takes for co2 rise to accumulate significantly. It isn't that it's the dominant factor of daily temperature variation in say London (as obviously the dominant factor there is Earth's rotation) or the dominant factor of average temperature over millions of years (simply because we are only going to elevate co2 levels significantly at most for 1000 years) Because some effects which have a significant effect over short time periods don't have a significant effect over long time periods (and vice versa). For example ENSO affects the temperature a lot over a single year. A strong el nino will make a very warm year, or a strong la nina year will make a very cool year. But over say 30 years the el ninos and la ninas largely come in equal number and cancel out therefore dampening their effect on a multi-decadal time scale.
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