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Post by steve on Oct 20, 2009 10:51:33 GMT
Do I assume that you don't have an answer to my questions:
What evidence do you have that the apparently widely accepted evidence of a 6-13micron window is wrong despite evidence of obs taken on cloudyish days in Central England, and at Kitt Peak which, at a mere 7000 feet often has relative humidity in the 50% region or so?
Why do you keep saying it was a "tethered balloon". Why is that relevant?
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Post by nautonnier on Oct 20, 2009 11:52:47 GMT
SoCold - are you an automaton? We clarify that you are unaware of the workings of GCM and do not know the power of the climate to carry energy to the tropopause by other means other than radiation. I know energy is transfered upwards by convection (which has a cooling effect on the surface). But I don't have numbers. I know that a 3.7wm-2 reduction in energy loss has to be balanced. The climate cannot stay the same. Doubling co2 therefore cannot have "no effect" as skeptics such as Reid Bryson have tried to claim. Furthermore I know that people who have run the calculations for convection, lapse rate, etc have consistently found strong warming from a 3.7wm-2 radiative forcing and noone has been able to show calculations for how low climate sensitivity can plausibly work in the atmosphere. So it's simply an idea without any numerical basis. One thing I know is that modelers have been unable to show such a thing. They consistently find the change in the hydrological cycle involves an increase in water vapor in the atmosphere which causes additional warming. There is a negative feedback from lapse rate change, but this isn't as large as the positive feedback from water vapor increase. Unfortunately for the modelers the ERBE measurements disagree with them too. Perhaps they should return to their base assumptions or parameterizations and see if they can get a model to match the real world. The increase in water vapor increases convection which causes cooling. But then the models only really consider absorption of radiation and not convective 100kt updrafts carrying liquid water right up to the tropopause where it dumps huge amounts of latent heat and forms nice reflective albedo increasing ice clouds. Back to the one club golfing again - only ever considering radiation. That's fair at the TOA but woefully inadequate in the troposphere. |
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Post by radiant on Oct 20, 2009 12:21:55 GMT
Do I assume that you don't have an answer to my questions: What evidence do you have that the apparently widely accepted evidence of a 6-13micron window is wrong despite evidence of obs taken on cloudyish days in Central England, and at Kitt Peak which, at a mere 7000 feet often has relative humidity in the 50% region or so? Why do you keep saying it was a "tethered balloon". Why is that relevant? Most school boys can probably explain to you why an infra red observatory is placed on top of a mountain to minimise the effects of emission by water which is one of the strongest apparently transparant materials in the area of IR emission which is known to humans - even if sometimes the humidity there is high. The nasa measurements from space made 30 years ago were only up to 25 micron. The far infrared goes to 100. A school boy can probably explain what that means to you. Nasa tell us today this was because of the technical problems of placing a cooled detector in space. Many school boys can explain this further i am sure. Today out in the desert, Nasa are flying equipment from a balloon to test how it performs before attempting to measure the emission of earth from space for the first time over the full spectrum. Please refer to school boys who can explain this to you Instead of refusing to learn and asking stupid questions you need to study this topic and then make intelligent comments about it. It appears that no matter what i attempt to tell you refuse to learn while telling me you know more about this topic than i do The way to learn is to realise we know nothing and then allow what we dont know to be received |
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Post by magellan on Oct 20, 2009 13:12:37 GMT
1. The 3.7 number is empirically derived. It is a relatively simple calculation to do based on two reasonably well known sets of quantities - a profile of the earth's atmosphere and emission/absorption characteristics of materials and gases. It is an estimate based on tunable parameters, it is not empirical. It is questionable if you even understand what empirically derived means. You also fail to mention earlier estimates in IPCC were placed at 4.3 Wm 2, which was also derived from parametrization. When observations did not support such high estimates, including 3.7, the aerosol card was played to explain this inconsistency. Why does it matter what I call it. Empirical is fine I think because it is based on application of radiative transfer to an atmosphere profile based on observations rather than it being any sort of innate effect of CO2. Criticising what I call it, and bringing in suggestions of "tunable parameters" doesn't really change the fact that largely the figure is accepted as likely being close to the right answer. Also, I don't really care if it used to be 4.3. I don't think the world is 15% safer for the change. It is a detailed calculation, and the science moves on. As it happens the change is not attributed to aerosols by Myhre 1998, and I doubt very much that any observations were sufficient to spot the 15% error. Mr Cripwell will be asking you for that paper if it truly exists  . The GCM is of course tested against observations. I don't quite see where you get this testing a hypothesis against a hypothesis from/ We're aready enough off-topic, and I'm hardly an expert, so I'll just say that negative feedbacks between 1985 and 1999 do not appear to square with observed ocean and atmosphere warming over the same period. Lindzen appears to have looked at a subset of periods within this time based on periods of rapid SST change, and he has looked in the tropics. A possible solution to the conundrum is that the periods and the locations are overly selective. Perhaps in the real world, the processes that cause a rise in SSTs are correlated with the processes that cause clear skies. His model comparisons are atmosphere-only models where the SST changes are an input to the model. Probably he needs to run GCMs (ie. models which include an ocean model) and then look at the GCM output to find periods where the ocean SSTs change in the same way as the observations, and then compare the radiation balance. That would be a fairer comparison surely. The GCM is of course tested against observations. I don't quite see where you get this testing a hypothesis against a hypothesis from/ Apparently you have not read or understand the Lindzen article. It is so fundamental there really is no room to argue about the results. Which observations are that? By admission cloud dynamics are on the very low end of scientific understanding spectrum in IPCC AR4 and you have the gall to say GCM's are tested against observations? A small change in cloud cover can upset the entire model. If only one metric is in error, the model is invalidated, hence GCM's must constantly be parametrized (fudged) to agree with observations, albeit very weakly. As Lindzen points out, GCM's cannot replicate ENSO events or any other cyclical feature of weather/climate because it is so incredibly complex and knowledge (despite hubris of some) is low. Name the models and dates when they were tested against observations, including that of clouds and how clouds are formed and react to changes in weather. Further, provide a model that has been validated by independent analysis, including that of the code. By independent analysis, that does not include other modelers! I don't quite see where you get this testing a hypothesis against a hypothesis from That is perhaps one of the silliest things I've seen posted in this forum in a long time. An experiment cannot be conducted to test a hypothesis by using a hypothesis to test (proof) it. A GCM is by strict definition a hypothesis, so it cannot be used to prove anything. Must I look it up for you? I don't like beating dead horses, but you and socold have blinders on concerning Lindzen's paper based on two very fundamental components: 1) model predictions 2) observations The observations disagree with the hypothesis (model), test fails. Period, end of story, back to the drawing board. |
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Post by jimcripwell on Oct 20, 2009 13:47:54 GMT
I am giving up posting on this thread. I have already contributed all the science I know. My advice to fellow skeptics is to do likewise. On this topic the warmaholics are quite clearly not interested in any sort of scientific discussion.
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Post by steve on Oct 20, 2009 14:03:56 GMT
Radiant,
Just a while ago you were telling me that no IR could get through to even 5500 metres because water vapour was so wonderful at absorbing it. So I'm glad you appear to be starting to agree with me now. At 4200m, Mauna Kea has telescopes sensitive in the 8-13 micron and 16-25 micron window for example.
Obviously, a tethered balloon at 950mbar on an autumn day can also see the window at 6-13microns because the humidity at 950mbar in Central England on an autumn day is low enough to allow passage of infrared. So you are agreeing with me again.
And we can be in agreement that the CO2 in the atmosphere at the height of many mountain telescopes (and even Kitt Peak at the height of 6800 feet which is even higher than Ben Nevis!) could be an important absorber and emitter of radiation because the humidity is low enough to allow observations in the 6-13 micron region at certain times.
It's nice to come to an agreement in such a constructive way.
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Post by steve on Oct 20, 2009 14:15:39 GMT
Magellan
That is a very unscientific statement.
OK so I listed my suggestions as to why Lindzen's selection of data might not be the whole story, and why an atmosphere-only model might not be appropriate, and you've decided to ignore it. Please don't say I've never commented on the paper again.
And an AMIP run will never replicate ENSO because it *has no ocean model*. Did you realise that? I did say.
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Post by radiant on Oct 20, 2009 15:01:07 GMT
Radiant, Just a while ago you were telling me that no IR could get through to even 5500 metres because water vapour was so wonderful at absorbing it. So I'm glad you appear to be starting to agree with me now. At 4200m, Mauna Kea has telescopes sensitive in the 8-13 micron and 16-25 micron window for example. Obviously, a tethered balloon at 950mbar on an autumn day can also see the window at 6-13microns because the humidity at 950mbar in Central England on an autumn day is low enough to allow passage of infrared. So you are agreeing with me again. And we can be in agreement that the CO2 in the atmosphere at the height of many mountain telescopes (and even Kitt Peak at the height of 6800 feet which is even higher than Ben Nevis!) could be an important absorber and emitter of radiation because the humidity is low enough to allow observations in the 6-13 micron region at certain times. It's nice to come to an agreement in such a constructive way. So the balloon was approximately 1200 feet. I think they were measuring the earth? Meanwhile we seem to have agreement that the atmospheric window to outerspace is visible from a low altitude balloon in conditions of low humidity or from a higher mountain based observatory Or alternatively we agree that you can observe earth via the atmospheric window from a low altitude balloon in conditions of low humidity. So far we have no evidence of low altitude observations of space via the atmospheric window in usual humidities. If you have it please present it here in easily readable form. Autumn in the uk can be frosty indicating low water vapour content. These things should be easily resolved and not require endless argument. The authors said exceptionally clear conditions. What creates such conditions? I think you will find that my comment about 18000 feet (you use 5500 m usually) was that terrestial emissions are easily absorbed by the water vapour present in the atmosphere, and higher emissions are easily absorbed at the lower altitudes? However i am also saying that mesosphere water content is also significant to absorptions as is thermosphere absorptions I am saying it is significant because of the exstraordinary absorptive power of water in any of its forms as demonstrated by Tyndall and in the absense of a spectra of water emission other than one from 2.6 3.6 microns. Below you can see a spectrum of the water of a star detected by a space bound telescope cooled with a 5 year supply of liquid Helium!!   So it appears that in that region of 14 to 17 microns there were no modeled areas where water does not absorb and there are two very narrow areas of none absorption as measured. I am not sure what the following is saying about the none spiked areas of the model. Are they myriads of smaller lines or no lines? spitzer.caltech.edu/images/1860-ssc2007-14a-Spitzer-Sees-Water-Loud-and-Clear-in-a-Young-Solar-System |
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Post by steve on Oct 20, 2009 16:03:46 GMT
The main point really is that the atmosphere is not so opaque to water vapour if profiles of the atmosphere can be taken at a height of only 950mbar. Even if those days were lower humidity than average, their is no suggestion in the paper that they were abnormal. So there is a) common weather conditions when levels of other greenhouse gases are important even at relatively low levels, and b) evidence that the emissivity of water is not a guide to the emissivity of water vapour.
Now I've never looked into this too hard, because based on my rough physics based understanding (application of Stephan-Boltzmann), the important layers of the atmosphere for radiating to space are the layers around where the temperature is about 250 Kelvin (this is the "temperature" that the earth needs to be to retain radiation balance with the absorption of solar radiation). This layer is a few km up where I am pretty sure that while water vapour *is* important, CO2, CH4 and other greenhouse gases are important too.
At a guess, the mesosphere spectra will be different again because it is tenuous. For one thing, tenuous gases tend to give you much thinner spectral lines.
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Post by icefisher on Oct 20, 2009 18:15:43 GMT
Now I've never looked into this too hard, because based on my rough physics based understanding (application of Stephan-Boltzmann), the important layers of the atmosphere for radiating to space are the layers around where the temperature is about 250 Kelvin (this is the "temperature" that the earth needs to be to retain radiation balance with the absorption of solar radiation). This layer is a few km up where I am pretty sure that while water vapour *is* important, CO2, CH4 and other greenhouse gases are important too. Well there are at least 4 layers in the atmosphere that is at 250 kelvin. troposphere, stratosphere, mesosphere, and thermosphere (maybe the exosphere too?). Why are these layers important? Seems to me that all 250 kelvin represents is a mean. . . .but with 4 250k layers I am not sure its where the mean is located. |
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Post by radiant on Oct 20, 2009 19:36:16 GMT
The main point really is that the atmosphere is not so opaque to water vapour if profiles of the atmosphere can be taken at a height of only 950mbar. Even if those days were lower humidity than average, their is no suggestion in the paper that they were abnormal. So there is a) common weather conditions when levels of other greenhouse gases are important even at relatively low levels, and b) evidence that the emissivity of water is not a guide to the emissivity of water vapour. Now I've never looked into this too hard, because based on my rough physics based understanding (application of Stephan-Boltzmann), the important layers of the atmosphere for radiating to space are the layers around where the temperature is about 250 Kelvin (this is the "temperature" that the earth needs to be to retain radiation balance with the absorption of solar radiation). This layer is a few km up where I am pretty sure that while water vapour *is* important, CO2, CH4 and other greenhouse gases are important too. At a guess, the mesosphere spectra will be different again because it is tenuous. For one thing, tenuous gases tend to give you much thinner spectral lines. Do you have the text for this paper online?? It makes it clear in the abstract visibility was very good. Water vapour as measured in the laboratory has the 8-13 window where the absorption is 10,000 times less than liquid water but water forms clusters in the gaseous state that behave like water. Hundreds of feet of water in air in the atmosphere at low temperatures is not like a few feet of steam in a laboratory at 100C This guy seems to have blazed a trail on this against some opposition www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA299836&Location=U2&doc=GetTRDoc.pdfAnd this seems to be picked up by this paper kb.osu.edu/dspace/handle/1811/13438Theoretical models of the water vapour continuum are based on data which contain uncertainties and are sometimes inconsistent. The major reasons for this are the small size of the absorption coupled with the low saturated vapour pressure of water at atmospheric temperatures, which limits the total absorption in any conceivable laboratory path. Recognising the need for improved continuum measurements, we are currently developing a cavity ring-down experiment, in order to study the water vapour continuum. And from that literature review i quoted earlier www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=CP&Year=2002&ManuscriptID=b200372d&Iss=9 the calculated average atmospheric absorption is about 25% (25 W m–2) less than observed......... It has been suggested that errors in the water line intensities,160,161 missing weak water lines,162 water dimers,163 water continuum164 and clouds165 are all possible contributors to the missing absorber problemThe obvious issue with water vapour as it is presented to the public is that very narrow spectral ranges are shown which distort the significance of the minor green house gases and part of that problem is that the space bound measurements are so narrow with only about 20 microns of about 120 microns and more of water significance since water radiates thru the far red and thru the next band into the microwave region Then we hear of the atmospheric window which may or may not exist in the real world of miles of atmosphere to absorb waters continuum absorptions and pass it to the strongly radiating other water emissions And other than one picture from 1974 dispite days of looking i have yet to see this window from space dispite you telling me you have shown it exists Where actually does it exist?? |
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utahpaw
New Member
The only thing that keeps us from learning is what we already know.
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Post by utahpaw on Oct 21, 2009 0:31:00 GMT
It's a common confusion, neither are incorrect, they are residence times for different things. Apples and Oranges. The 5 years is the residence time for an average molecule of co2. That's true even if atmospheric co2 level isn't changing. The longer time frame is how long it takes for a rise in co2 level to drop back down to where it started. The paper, the article and the website are just total BS. socold, Aim before you shoot, please! Let's assume a baseline of 10 molecules of CO2 in the atmosphere, and we have had a hot air excursion that caused there to be 11 molecules of CO2 in the atmosphere, whereupon the forcing agent vanished. In this average new world, one CO2 molecule is added to the atmosphere after 6 months, and normally one is removed after the same interval. However, because of the excursion to a CO2 level of 11, and the average residence time of 5 years, 1.1 molecules are removed after 6 months, leaving the CO2 content of the atmosphere at 10.9 molecules six months after the extra forcing was removed. After six more months, one more molecule is added, and 1.09 molecules are removed, leaving 10.81 molecules in the atmosphere one year after the forcing event. Only 10.729 remain after 18 months. Only 10.6561 remain after two years. (This is easier than using the Deltas and Epsilons of The Calculus, though it does require splitting the atom....) Hmmm. At only 3.5 years, we have already crossed the halfway point to "normal" 10! But, thanks to Zeno's paradoxical observations, we soon realize: WE WILL NEVER get rid of all the excess, not even after 1000 years! Global Warming will be with us FOREVER!!! |
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Post by sigurdur on Oct 21, 2009 2:07:41 GMT
It's a common confusion, neither are incorrect, they are residence times for different things. Apples and Oranges. The 5 years is the residence time for an average molecule of co2. That's true even if atmospheric co2 level isn't changing. The longer time frame is how long it takes for a rise in co2 level to drop back down to where it started. The paper, the article and the website are just total BS. socold, Aim before you shoot, please! Let's assume a baseline of 10 molecules of CO2 in the atmosphere, and we have had a hot air excursion that caused there to be 11 molecules of CO2 in the atmosphere, whereupon the forcing agent vanished. In this average new world, one CO2 molecule is added to the atmosphere after 6 months, and normally one is removed after the same interval. However, because of the excursion to a CO2 level of 11, and the average residence time of 5 years, 1.1 molecules are removed after 6 months, leaving the CO2 content of the atmosphere at 10.9 molecules six months after the extra forcing was removed. After six more months, one more molecule is added, and 1.09 molecules are removed, leaving 10.81 molecules in the atmosphere one year after the forcing event. Only 10.729 remain after 18 months. Only 10.6561 remain after two years. (This is easier than using the Deltas and Epsilons of The Calculus, though it does require splitting the atom....) Hmmm. At only 3.5 years, we have already crossed the halfway point to "normal" 10! But, thanks to Zeno's paradoxical observations, we soon realize: WE WILL NEVER get rid of all the excess, not even after 1000 years! Global Warming will be with us FOREVER!!! Can't make it much more simple UtahPaw. Even my child understood that one. |
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Post by nautonnier on Oct 21, 2009 9:48:00 GMT
socold, Aim before you shoot, please! Let's assume a baseline of 10 molecules of CO2 in the atmosphere, and we have had a hot air excursion that caused there to be 11 molecules of CO2 in the atmosphere, whereupon the forcing agent vanished. In this average new world, one CO2 molecule is added to the atmosphere after 6 months, and normally one is removed after the same interval. However, because of the excursion to a CO2 level of 11, and the average residence time of 5 years, 1.1 molecules are removed after 6 months, leaving the CO2 content of the atmosphere at 10.9 molecules six months after the extra forcing was removed. After six more months, one more molecule is added, and 1.09 molecules are removed, leaving 10.81 molecules in the atmosphere one year after the forcing event. Only 10.729 remain after 18 months. Only 10.6561 remain after two years. (This is easier than using the Deltas and Epsilons of The Calculus, though it does require splitting the atom....) Hmmm. At only 3.5 years, we have already crossed the halfway point to "normal" 10! But, thanks to Zeno's paradoxical observations, we soon realize: WE WILL NEVER get rid of all the excess, not even after 1000 years! Global Warming will be with us FOREVER!!! Can't make it much more simple UtahPaw. Even my child understood that one. And all based on totally linear assumptions - wouldn't weather forecasting be simple if things were linear instead of chaotic |
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Post by steve on Oct 21, 2009 11:17:32 GMT
Yes I have read the paper. The comments about visibility relate to amounts of pollution.
Yes I am learning that the spectrum of water vapour is exceedingly complex, and dependent on the level of humidity as it is on pressure and temperature. So the observational evidence is merely put to show that there seems to be a window in the spectrum that can be observed from regions above 950mBar (which is not that high) and that the details of this window have been tested against the radiation transfer equations to at least some degree.
It isn't a strong conclusion, but it is enough to be reasonably confident that there remains a role for gases other than water vapour throughout much of the atmosphere.
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