9,25 – a factor that could close the global warming debate
Guest post by Frank Lansner (hidethedecline)
The CO2-sensitivity describes the warming effect induced by a doubling of the CO2 concentration in the atmosphere, and is thus the epicentre of the global warming discussion. Estimates of the CO2 sensitivity are very different, and the value range used by IPCC appears unlikely to physically impossible. To show this, I will focus on the factor “Fw” between the total CO2 warming and then the warming from a single doubling of CO2 concentration.
The total CO2 warming effect is obviously many times bigger than the warming from a single CO2 doubling. Example: When changing CO2 concentration from 5 ppm to 320 ppm we have 6 doublings. But on top of these 6 doublings, how much warming effect is introduced when CO2 concentrations are changed from 0 to 5 ppm etc? In the following I use the online model MODTRAN:
Fig. 1. Above is illustrated the warming effect of CO2 for 3 different climatic areas. Zero W/M2 represents the net forcing of the atmosphere fore a given scenario with CO2 concentration set to 0 ppm.
For each area is shown a clear sky scenario as well as a light rain scenario. All other variables in MODTRAN are left as the default values. The results from MODTRAN are total atmosphere outgoing radiation, and thus when changing concentrations of CO2 we get total atmosphere responses incl feedbacks if present.
Fig 1 Shows 6 doublings of CO2 concentration: 5-10-20-40-80-160-320 ppm where every doubling shows warming effect of similar size (–as could be expected due to the logarithmic declining effect of adding more CO2 to the atmosphere).
From the graph above we can see that the total CO2 warming effect today equals around 9 times the warming effect of one doubling of CO2 concentration.
Fig 2. For a better compare between the scenarios on fig1, these are now shown as %-values of the total CO2 warming effect for (Forcing) with today’s concentration of 390 ppm CO2, equals 100%. It appears that clear sky, rainy sky, Arctic area, tropics, subtropics scenarios has a very similar profile indeed and I find that this result shows that we can consider these %-trends to be rather global.
Fig 3. The average global CO2-doubling can now be calculated more accurate to be near 10,8% of the full CO2 warming effect at 390 ppm. (Or, the “CO2-sensitivity” warming effect is around 10,8% of the total CO2 warming effect, globally.)
Thus, the “best estimate” of the factor between total CO2 warming effect and the warming effect from one CO2 doubling – Fw – can be calculated. Best estimate (so far) Fw = 9,25.
CO2-warming-total (K) = 9,25 * CO2-warming-from-one-doubling (K) = 9,25 * CO2 sensitivity (K)
I have used MODTRAN for this result, but it is universal that the doublings must have near same warming effect and thus the individual doubling will have just some fraction of the total value. For now, the factor 9,25 is best estimate.
Hansen – CO2 sensitivity.
Now how does the factor 9,25 between total CO2 warming effect and CO2 warming effect from a single doubling support the viewpoints of James Hansen on CO2 sensitivity?
James Hansen often refers to a CO2-sensitivity of 6 K… 6 K warming effect for each single CO2 doubling:
Fig 4 James Hansens CO2 sensitivity of 6 K gives around 55,5 K of total CO2 effect using the factor Fw = 9,25. As the total warming effect of all greenhouse gasses is assumed to have a warming effect of approx 33 K, the Hansen CO2-sensitivity demands that the total CO2 related warming effect is bigger than all the greenhouse gasses effect combined.
The overall CO2 warming effect is supposed to be around 10-15-2% of the total warming effect of the atmosphere, here we use 15%. Since CO2 is assumed to account for 15% of the total 33K greenhouse effect on Earth, the CO2 total warming effect is around 5 K. So just ONE CO2 doubling of Hansen’s CO2 sensitivity of 6 K has a bigger warming effect than the total warming effect supposed to be possible.
It is therefore highly odd that Hansen’s claim of 6 K CO2 sensitivity has been taken seriously anywhere at any time.
Here the “greenhouse wheel” (see WUWT post Wheel! – – Of! – – Silly!) where supposedly scientists imagine that we by year 2100 can have warming of over 7 K in fact with less than one CO2 doubling to cause this:
Fig 5. To account for their 7 K temperature increase, they must have played with a CO2-sensitivity of perhaps 10 K? So these honourable “scientists” believes that one CO2-doubling might resemble a third of the combined earth greenhouse effect?
IPCC – CO2 sensitivity
Then, how does the factor 9,25 between total CO2 warming effect and CO2 warming effect from a single doubling support the viewpoints of IPCC on CO2 sensitivity?
IPCC AR4 viewpoints for the CO2 sensitivity :
http://en.wikipedia.org/wiki/Climate_sensitivity
IPCC “best estimate” of warming from one CO2 doubling is 3 K.
Using the Fw = 9,25 we learn, that if one doubling warms 3 Km then the total CO2 warming should be around 28 K ( = 9,25 * 3 )
We must then remember again that the total warming effect of the atmosphere is generally accepted to be near 33 K. The warming effect related to CO2 should then be around 85% of the total Earth atmosphere greenhouse gas effect. And without CO2, the atmospheres warming effect should be reduced to 15% of todays atmosphere…. On a globe with mostly water-ocean surface…
The IPCC numbers where each doubling of CO2 represents 3 K it simply does not fit at all with the total warming effect of the atmosphere.
IPCC then claimed:
“Values substantially higher than 4.5°C cannot be excluded..”
Well, 4,5 K for CO2 sensitivity gives a total CO2 effect of 41,6 K. This is 126% of the total earth greenhouse effect, so we could rephrase:
IPCC:
“Values of CO2 related warming substantially higher than 126% of the total greenhouse gas warming cannot be excluded..” …
Idso´s and Lindzens estimates for CO2 sensitivity.
What if we assume that CO2 is responsible for the 15% of the 33K greenhouse warming effect on Earth? This corresponds to 5 K. If true, the CO2 warming from one doubling should be
CO2 sensitivity = CO2warming-total / Fw
CO2 sensitivity = 5K / 9,25 = 0,54 K
So just using the generally accepted knowledge that CO2 sholuld account for around 15% of the total Earth greenhouse effect, and using the also generally accepted knowledge that total Earth greenhouse effect is 33K, then the CO2 sensitivity should be near 0,54K
Idso 1998 suggests 0,4 K, and Lindzen suggests 0,5 K these results appears sound and realistic in strong contrast to values from IPCC and Hansen.
Hansens 350 ppm ”safe level”
Fig 6. When working with CO2 – effect, one cant help wondering what Hansens ”safe level” of 350 ppm CO2 is all about.
Fig 7. NASA´s, James Hansen has claimed 350 ppm to be a safe level of CO2:
– Just 1,5 % less Warming effect from CO2 and we are “safe”.. ?
If CO2 has a total warming effect of 5 K – as previously calculated – the difference between the Hansen “safe level” CO2 warming and todays level is around 0,075 K.
I wonder if the peoble creating the 350 ppm demonstrations knows this?
I wonder how they will react when they find out.
Idso 1998:
http://www.int-res.com/articles/cr/10/c010p069.pdf
MODTRAN:
http://geoflop.uchicago.edu/forecast/docs/Projects/modtran.orig.html
Wayne says: “Radiation in CO2’s bands are completely absorbed low in the troposphere so adding absorber molecules only shortens the path to first absorption”
Is this to some degree explaining why the upper atmosphere has been cooling for decades?
K.R. Frank
george smith
“Well I have no idea who or what MODTRAN ”
it’s one of a class of models that has been around since at least 1985 when I first used it. If you want to engineer something and need to understand how radiation ( IR for example) transfers through the atmosphere, then MODTRAN is the tool you use. If you want a very accurate estimate you would use a LBL model.
tim Clark:
“If so, then explain why current global temps are lower than predicted by IPCC using a climate sensitivy of 3? ”
well, I dont buy a sensitivity of 3, precisely for that reason. There are a couple ways to estimate sensitivity. Sometimes you can estimate it from observation, but you need a bunch of data. When you dont have enough observation data you HAVE to build a model. Even then you can get big ranges.. see the IPCC ranges. So, the debate, the real debate, is over sensitivity. That’s the open question. that’s the smart question. distractions like “Co2 is just a trace gas” and other skeptical misunderstandings just keep people from engaging on the real issue. Luckily, skeptics like Christy, Lindzen, spenser, Monkton, etc, all accept the basic physics. C02 warms. They get to have conversations with other scientists because they dont reject known physics.
I was a little surprised at the shape of the graph presented in this article until I found that the author was using multiple scales on the horizontal axis. It begins with a linear scale, changes to a logarithmic scale at 5 ppm CO2 and then reverts to linear scale again at 320 ppm. The obvious breaks in the curve are just the result of the varying scales being used.
“”” mkelly says:
September 8, 2010 at 1:38 pm
George E. Smith says:
September 8, 2010 at 11:31 am
…and that is the earth surface; which varies in Temperature over an extreme range of from 120 to 150 deg C from the coldest Antarctic midnight highlands; to the hottest midday tropical deserts; and over that range the surface emission varies by over an order of magnitude; from about double the 390 W/m^2 that Trenberth gives (corresponding to a 288 K Temperature, to about 1/6th of trenberth’s number for the coldest regions.”
You have again stated much of what I have said many times. If we accept CO2 absorbtion lines at 15 micro that has an associated temperture contained in it. That temperature is 200K, give or take. The earth at 300K (10 micro) does not radiate in the proper band for CO2 to absorb anything let alone radiate back down to heat the ground. “””
Well I take it as a given that at first glance anythermal radiation spectrum is somewhat “Black Body” like; so unless it is a totally weird surface; it radiates roughly proportional to the fourth power of Temnperature; although its total emissivity may not be 1.0 and it may have a spectral emissivity that puts some holes in the BB spectrum. Also the spectral radiant emittance at the wavelength peak out to vary as about the fifth power of the Temperature (Kelvins).
For a BB at 288 K which is about what the mean earth surface is supposed to be; that gives you about 390 W/m^2 and the spectral peak is at 10.1 microns. But in keeping with all BB spectra; about 98% of the energy is contained in the raneg from 0.5 of peak wavelenght to 8 times the peak wavelength.
So realistically a mean earth surface such as a 15 deg C water surface should emit a spectrum from about 5.0 microns to 80 microns; and the CO2 15 micron (13.5-16.5 micron) band is certainly in that range.
But at the coldest Vostok like Temperatures the spectral peak is right at 15 microns; but the total emittance is about six to seven times lower than at 15 C. For the highest desert temperatures; the emittance goes up by from 1.8 to 2.0 times and the peak wavelength drops to around 8.7-8 microns. So even at this temperature (+60 C) there is no more than 1% max to be found anywhere near the other 4.0 micron CO2 line; which basically does much of nothing on earth; since only 1% of sunlight is out that far in the infrared either.
So there isn’t any quastion (in my mind) that CO2 and H2O as well do intercept some fraction of the earth thermal emission; but I don’t see how a 13.5-16.5 band can collect 90% of the total mean temp surface emission which is what Trenberth claims. (only 40 W/m^2 escapes out of the 390 W/m^2 emitted by the surface). There’s no way that a 13.5 to 16.5 window takes out 90% of the energy from a 288 K BB radiator.
Besides that 13.5-16.5 slot is actually many very fine slots that are much narrower than the 3.0 micron band width.
And others here have intimated that Temperature and Collision broadening are not major effects at these Temperatures.
So I guess MODTRAN does an actual Physics calculation of all the absorptions and emissions from the atmosphere with its GHG trace gases. So why is the final result not widely known all over the earth ?
I would presume that Trenberth’s global energy budget cartoon; would be a summary of MODTRAN projections of what the atmosphere does. Is it ??
If MODTRAN is an accurate atmospheric Physical model; then why wouldn’t it be the standard model; so that all these measurments didn’t have to be made.
Frank Lansner said
cal says:
September 8, 2010 at 6:43 am
“Introducing some CO2 would therefore have a major impact with strong positive feedback as water evaporated. ”
Maybe so, but where is the extra water in the atmosphere since 1948?
You seem to have completely missed my point. My argument does not need any more water vapour in the atmosphere or any less for that matter.
My point is that the sensitivity to CO2 is extremely unlikely to be constant for all the doublings. So although your argument might be true it is no more convincing than Hansens view.
The quote above relates to the hypothetical first introduction of CO2 to an earth that does not have any. The earth’s surface would be at an average temperature of about -20C. Almost all the world would be covered in ice for some of the year and a large part would be ice covered for all of the year. The level of moisture in the air would be very low. There would be few clouds and little precipitation.
The addition of 1 ppm CO2 would increase the temperature by a certain amount as a direct result of the reduction of radiation in the 13-18 micron band. For arguments sake let’s assume this is 4K. A further doubling would probably increase the temperature by roughly the same amount. During the next doubling the temperature would reach the point where significant water evaporates. Initially this would add water vapour as a potent greenhouse gas that would increase the sensitivity to say 6K for the next doubling and 8K for the fourth. After that the surface temperature would be such that clouds would start to form along with the beginnings of Hadley cells transporting large quantities of heat to the upper atomsphere. These would both be extremely strong negative feedbacks. It seems to me entirely possible that at some point in the doubling senario that the temperature actually goes down as CO2 rises. So the first four doublings may induce a total increase of 22K the next doubling 4K the next doubling 2K the next 0K the next -2K the next 0K the next 3K then next 4K then next who knows? The total is 33K but the progress is in no way linear. I am not suggesting that these are the real figures but I believe they are jst as likely as those based on the assumption of constant climate sensitivity over all levels of CO2.
In other words the concept of climate sensitivity being a constant makes sense for small changes in CO2 but it does not make sense for the gross changes you are modelling. By the way I could very easily be convinced that we are still in the situation where the cloud and convection effects give a negative sensitivity. Just show me the data! That goes for Hansen too.
“They get to have conversations with other scientists because they dont reject known physics.”
ewwww…..
Well, next time you go to your refrigerator or turn on the air conditioning while you chat with the l33t, you can give silent thanks to a real engineer who makes physics work- be very grateful he didn’t try to charge the system with CO2.
George E Smith says
So there isn’t any quastion (in my mind) that CO2 and H2O as well do intercept some fraction of the earth thermal emission; but I don’t see how a 13.5-16.5 band can collect 90% of the total mean temp surface emission which is what Trenberth claims. (only 40 W/m^2 escapes out of the 390 W/m^2 emitted by the surface). There’s no way that a 13.5 to 16.5 window takes out 90% of the energy from a 288 K BB radiator.
This was in answer to mkelly. I think your post was overall well thougth through. In answer to this point my understanding is that CO2 radiates 18% of the earth’s energy budget from the upper part of the troposphere and the tropopause. Water vapour radiates much of the remainder from various levels in the troposphere. My guess is that the 40 watts is a purist view of what the surface radiates at wavelengths where there is no photon aborption by any molecular species in the atmosphere. This so called atmospheric window around 10 micron is quite small and may well let only 10% through. I am not sure that it means much since many of the water absorption modes are very weakly interacting so their re-emission into space occurs quite close to the surface and at temperatures not too far from that at the surface.
I do not know the actual Trenberth statement but my guess is that he states the 40 watts to allow the reader to make the false assumption that the remainder is stopped by CO2. It is another one of their tricks!
MODTRAN and its predecessor codes for calculating the SIGNAL transmittivity (or target radiance) in remote sensing do a remarkably fine job of it. But they do NOT solve the thermodynamic problem of HEAT transfer in the geophysical setting, where convection of moisture from the ocean surface plays a central role in heating the bulk constituents of the atmosphere. The basic difference between these distinct concepts is seen starkly in the treatment of beam extinction, such as occurs with 15 micron terrestrial radiation. Signal transmittivity at that wavelength is effectively zero, due to virtually complete absorption by CO2 and overlapping water vapor bands. Yet the thermal energy associated with that beam does not simply vanish; it is scattered by molecular collisions to other wavelengths and progressively finds its way to the heat sink of space. That’s why radiation-only calculations cannot be relied upon for determining the surface temperature and atmospheric profile in the realistic case.
RE: George E. Smith: (September 8, 2010 at 11:31 am)
“Well I have no idea who or what MODTRAN is, but you have to start with the primary source of LWIR radiation (if the CO2 greenhouse effect is what you are studying; and that is the earth surface…”
I believe MODTRAN is a computer program developed by the U.S Air Force to model infra-red radiation from the surface. There is an online MODTRAN calculating utility provided on the University of Chicago web site that allows one to calculate the radiation that might be observed at some high altitude, like 70 km, as a result of several given scenarios as mentioned by the author of this article. You may specify the sensor altitude, surface temperature offset from 300 deg K, the CO2 concentration, the methane concentration, ozone in the troposphere and stratosphere, and water vapor modeling options. I have saved results from 0 ppm, (393.56 deg K) to 143,360 ppm, (315.74 deg K) in clear tropical air.
By trial and error searching for temperature offsets required to produce a fixed standard observed radiation level (I use 292.993 w/sq m) one can use this tool to estimate the *raw* temperature forcing for various CO2 concentration levels.
Here is a link to some of my MODTRAN results from the online tool…
http://wattsupwiththat.com/2010/08/06/a-reply-to-vonk-radiative-physics-simplified-ii/#comment-452821
Steven Mosher says:
September 8, 2010 at 2:56 pm
“Sometimes you can estimate it from observation, but you need a bunch of data. When you dont have enough observation data you HAVE to build a model.”
HAVE to build a model?
Steven, I apologise for butting in with probably nowhere near the ability to contribute constructively, but can you please explain to an old gnarled and battered engineer, how, if you don’t have enough observational data and therefore justification, you can build a model?
What is wrong with – when we have enough justification and not until then, we will build a model?
Hmm. Of course the path length shortens rapidly with increased altitude. Not sure if I can answer that.
Good question though on the upper atmosphere. Let me do a little more scratching and digging and I’ll get back to you on that, it does need to be properly tied.
For anyone:
It seems to me Frank’s question ties somewhat to the thermalization of this heat after the initial absorption and thermalization. That quanta of heat, so to speak, can then be transferred by any of water’s or carbon dioxide’s bands in a reverse thermalization absorption manner across the spectrum once again, much as the surface radiates following a gray body curve. Water’s spectrum has a much larger number of possible bands to absorb in (therefore emit) than co2 but its concentration tails off rapidly at tropopause on the average. Some quanta of course will reverse-thermalize back to a co2 band but just a small fraction of it, each and every absorption, transfer and reverse-thermalization giving this quanta the ability to spread in a gray body manner ruled by the emissivity at each band. Then there is also the small continuum radiation by the atmosphere as a whole which can partially exit by window frequencies. Fancy way of explaining equipartition but important to know how.
Wing frequencies is another missed topic. Photons at these frequencies do absorb with lower emissivity chance but they also are emitted at wing frequencies that have a much larger chance to escape to space, due to the low emissivity of these wing bands.
Just had to get those thoughts out for everyone to ponder on for I never see them raised or included in these topics. You know, all of the physics while we are talking of it. If you leave out one portion soon the flow of discussion could be something that is not actually real. Could go on and on but I won’t right here.
Can someone please explain what concentrations of greenhouse components are thought to exist at the tropopause and whether there is any form of layering? The term “well mixed” seems to be bandied about with much abandon. If we skip way up to the thermosphere, it is generally accepted that layering occurs with the various elements sorting by molecular weight (obviously at extremely low densities). Also, a topic that has almost dried up recently, noctilucent clouds; these are now I believe thought to be water ice occurring at the mesopause. What is their increased occurrence of late telling us, there has been little if any follow-up that I’m aware of?
So why is a comma used instead of a decimal point, when writing in decimal notation? I don’t get that. How would you write 1,234.956 without using a decimal point and still get the correct number across?
Gnomish says:
“Folks who design and build heat pumps (most often for refrigeration) know better, Mr. Mosher. If it’s static, as the models and the idee fixee, it is not realistic. That is to say it is unreal and does not correspond with reality. That is to say to represent it as reality is insane. Insane, Mr. Mosher. Certifiably.”
well, Gnomish. Folks who designed and built heat pumps worked for us. And we built this:
http://en.wikipedia.org/wiki/Northrop_YF-23
If any of them suggested that MODTRAN (or LOWTRAN actually) was not a good tool to design working systems I think the Airforce would probably have asked that they be removed from the program, since MODTRAN/LOWTRAN has been through extensive testing: Just a few things for you to read. But seriously, questioning the output of MODTRAN isnt a good move. The real issue is what, if anything, does it say about the total amount of warming one sees AFTER feedbacks. MODTRAN is far too compute intensive to stick in a climate model ( as studies show) but you can probably look around and see that people test their “simpler” models against MODTRAN
And Modtran has been tested pretty extensively against LBL and observation. And don’t confuse transfers by convection, conduction and radiation
http://en.wikipedia.org/wiki/Radiative_forcing
http://gcmd.nasa.gov/records/GCMD_CDIAC_ICRCCM.html
http://adsabs.harvard.edu/abs/1990icrc.rept…..E
http://books.google.com/books?id=DxR2nEp0CUIC&pg=PA394&lpg=PA394&dq=Modtran+climate+models&source=bl&ots=ScLz9IhfEc&sig=wuGDnu16j1GnZqCkZHu-fQZ_Dkw&hl=en&ei=7EuITKWKLYT2tgPohtGDCg&sa=X&oi=book_result&ct=result&resnum=9&ved=0CE8Q6AEwCA#v=onepage&q=Modtran%20climate%20models&f=false
http://www.arm.gov/publications/proceedings/conf07/extended_abs/halthore_rn.pdf
http://adsabs.harvard.edu/abs/1997JGR…10216563H
http://en.wikipedia.org/wiki/MODTRAN
http://www.kirtland.af.mil/library/factsheets/factsheet.asp?id=7915
http://scholar.google.com/scholar?q=MODTRAN
http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=N9533732AH&q=MODTRAN&uid=789806831&setcookie=yes
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4689349
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V50-3WRJ13N-5&_user=10&_coverDate=04%2F30%2F1996&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1455255612&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=d7e13619320631c4e2470a2f89054498&searchtype=a
Verification and Validation
MODTRAN has been extensively verified and validated against FASCODE line-by-line calculations and measurement data. In a comparison of radiance codes for climate modeling (ICRCCM), MODTRAN was compared with three independent interferometer measurements of up-looking radiance and the overall agreement was excellent. MODTRAN UV radiance calculations were also compared with balloon measurements of transmitted solar energy to 40 km. Comparisons of MODTRAN and integrating sphere data for visible and near-IR integrated solar radiation have also been conducted. Detailed validation of the MODTRAN code has been performed recently using hyperspectral data from the AVIRIS visible/near IR airborne imager.
Verification and Validation Documentation
Philipona, R., E.G. Dutton, T. Stoffel, J. Michalsky, I. Reda, A. Stifter, P. Wendling, N. Wood, S.A. Clough, E.J. Mlawer, G.P. Anderson, H.E. Revercomb, T.S. Shippert, Atmospheric longwave irradiance uncertainty: Pyrgeometers compared to an absolute sky-scanning radiometer, atmospheric emitted radiance interferometer and radiative transfer model calculations, J. Geophys. Res., 106, 28129-28142, 2001.
Anderson, G. P., A. Berk, P. K. Acharya, M. W. Matthew, L. S. Bernstein, J. H. Chetwynd, H. Dothe, S. M. Adler-Golden, A. J. Ratkowski, G. W. Felde, J. A. Gardner, M. L. Hoke, S. C. Richtsmeier, B. Pukall, J. Mello and L. S. Jeong, MODTRAN4: Radiative Transfer Modeling for Remote Sensing, In Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI, Sylvia S. Chen, Michael R. Descour, Editors, Proceedings of SPIE Vol. 4049, pg. 176-183, 2000.
J. Hicke, A. Tuck, and H. Vomel, “Lower Stratospheric Radiative Heat Rates and Sensitivities Calculated from Antarctic Balloon Observations”, J. Geophys. Res., 104D, 9293-9308, 1999.
R.O. Green, B. Pavri, J. Faust, O. Williams, C. Chovit, “Inflight validation of AVIRIS Calibration in 1996 and 1997, Summaries of the Seventh Annual JPL Airborne Earth Science Workshop, JPL Publication 97-21, Vol. 1, Pasadena, California, pp. 193-203, 1998.
R. Meier, G.P. Anderson, C.A. Cantrell, L.A. Hall, J. Lean, K. Minschwaner, R.E. Shetter, E.P. Shettle, K. Stamnes, Actinic Radiation in the Terrestrial Atmosphere, J. Atmos. and Solar- Terres. Physics, 59, 2111-2157, 1997.
Halthore, R. N., S. E. Schwartz, J. J. Michalsky, G. P. Anderson, R. A. Ferrare, B. N. Holben, H. Ten Brink. Comparison of Model Estimated and Measured Direct-Normal Solar Irradiance, J.Geophys.Res., 102, D25, 29,991-30,002, Dec 1997.
J. Wang and G.P. Anderson, Validation of FASCOD3 and MODTRAN3: Comparison of Model Calculations with Interferometer Observations from SPECTRE and ITRA, in Passive Infrared Remote Sensing of Clouds and the Atmosphere II, David K. Lynch, Editor, Proc. SPIE 2309, 170-183, 1994.; also, Appl. Opt,35, 6028-6040, 1996.
K. Minschwaner, G.P. Anderson, L.A. Hall, R.J. Thomas, D. Rusch, A. Berk, J. Conant, Scattered Ultraviolet Radiation in the Upper Stratosphere, II: Modeling and Analysis, J. Geophys. Res., 100, 11165-11172, 1995.
H.E. Snell, G.P. Anderson, J.Wang, J.-L. Moncet, J.H. Chetwynd, S.J. English, Validation of FASE (FASCODE for the Environment) and MODTRAN3: Updates and Comparisons with Clear-Sky Measurements, The European Symposium on Satellite Remote Sensing, Conference on Passive Infrared Remote Sensing of Clouds and the Atmosphere III, Proceedings of SPIE, Paris, France, 1995.
G.P. Anderson, J.H. Chetwynd, J.-M. Th_riault, P.K. Acharya, A. Berk, D.C. Robertson, F.X. Kneizys, M.L. Hoke, L.W. Abreu, E.P. Shettle, MODTRAN2: Suitability for Remote Sensing, Proc. of SPIE, 1954, Remote Sensing, 1993.
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G.P. Anderson, F.X. Kneizys, E.P. Shettle, L.W. Abreu, J.H. Chetwynd, R.E. Huffman, and L.A. Hall, UV Spectral Simulations Using LOWTRAN 7, in Atmospheric Propagation in the UV, Visible, IR and MM-Wave Region and Related Systems Aspects, AGARD-CP-454, 1990.
RE: wayne: (September 8, 2010 at 5:53 pm)
“Wing frequencies is another missed topic. Photons at these frequencies do absorb with lower emissivity chance but they also are emitted at wing frequencies that have a much larger chance to escape to space, due to the low emissivity of these wing bands.”
I believe the important factor here is that the reduced absorption of these particular wavelengths will allow longer emission paths escaping the atmosphere. This may compensate for the equivalent reduced emissivity of these wavelengths. Perhaps there is an optimum absorption/emissivity factor that will remove the most heat from the upper atmosphere.
I found this presentation both interesting and confusing.
So I cut out the confusing parts.
http://rhinohide.wordpress.com/2010/09/08/lansner-reloaded/
Green Sand says:
September 8, 2010 at 5:23 pm (Edit)
Why do you have to build a model? well simply because you cannot solve the equations analytically. This happens all the time. The best example I can think of (its kinda close ) would be designing a flight control system ( coming up with gains ) for an aircraft. You cannot sit down and compute the exact gains required from first principles. So you build a model (computer model) of the aircraft and then spend hours trying to determine the right gain/gain schedule to get the kind of response you want. First Time I watched a guy do this I thought it was lunacy. Till he explained the problem. That’s kinda a toy version of the climate system.
Sorry, Mr. Mosher, for not being clear enough and making you waste all that energy chasing the infrared herring that way.
The very shortest way to restate my point, one hopes with better success, is to say ‘Radiation physics of CO2 is not the story of climate physics.’
The physics of climate ARE well represented by a heat pump with a working fluid, convection, phase change, huge amount of enthalpy with NO temperature change at all- and the ideal ‘infinite heat sink’. And temperature isn’t heat. You can’t say a thing about heat without stating something about mass.
Consequently I see CO2 as just another fetish ecstatics use for their unwholesome self flagellation. This whole thing is about self harming, in case you haven’t noticed.
The post shows that one doubling is worth about 3 W/m^2 with no feedback.
3 W/m^2 forcing corresponds to about 0.8 K warming with no feedback.
The IPCC 3 K number would correspond to 3/0.8*3= 7.2 W/m^2 with feedback.
The total greenhouse effect corresponding to 33 K is 150 W/m^2, of which maybe 30 W/m^2 is CO2, so the 3 W/m^2 from doubling is about 10% of its own total, which is where the 9.5 comes from. This 9.5 number seems irrelevant to the discussion of how much warming to expect from doubling CO2. You can compute it without knowing that, just from the 3 W/m^2 number for no feedback. Also 7.2 W/m^2 with feedback is only a small fraction of the total 150 W/m^2, and also is reasonable. The post is not doing anyone any favors in helping understanding these simple numbers.
On the other point, the IPCC report (Figure 3.20) shows that column water vapor is increasing 1.2% per decade using satellite data since 1988, not soundings that are unreliable for climate due to changing technology.
Can it be so hard to do an experiment with differing amounts of co2 in large container using x watts of IR – say using the astrodome or some such? Or fill a bunch of transparent balloons with varying amounts of co2 and the other atmo gases rigged with thermoms or pressure guages or something? Comon you physicists’ if its so important surely you can figure out some way to experiment and not have to guess.
Gary.
Start here:
http://agwobserver.wordpress.com/2009/09/25/papers-on-laboratory-measurements-of-co2-absorption-properties/
to do your kind of experiment you need a container the height of the atmosphere. have a look at Co2 in the stratosphere. And understand that we didnt realize how dry that region was until the 1950s or so when the Airforce studied it in order to build more survivable platforms. But again you can look at MODTRAN and get a very good idea. We know it’s physics are correct,largely. it’s been tested (see my post above) and it’s been used quite succesfully to build systems that defend our country.
Sorry Gnomish, The unfortunate fact is that our planet is warmer because of the way H20 (and other GHGs) in the atmosphere alter the way radiation ( err that stuff the sun puts out) enters and exits our system. I dunno, go argue with Monkton. he at least understands this, or Lindzen go argue with him.
Unfortunate for whom? Warmer than when?
Most of the planet is covered by water. The clouds are made of water. The water gets to the sky by the ton via phase change and convection. Any stray molecule mixed in is the same temperature as the rest and it goes along for the ride. I already showed the math on heat transport. Trace gas doesn’t get credit. Radiation physics of a trace gas hardly governs or even influences this process. It’s just riding on a conveyor to the infinite heat sink in the sky.
Every day the Hadley Cells, etc. and occasional giant vortices shoot water gas to the troposphere and spray condensed water back down.
There’s nothing unnatural going on but climate ecstatics with an odd fetish.
And to think that ‘weather’ used to be one of the few things anybody could chat about harmlessly…lol
Talk about hitting where it hurts!
Zeke… thanks for the graph 😉 !!!!
I think the picture is rather complex to say the least. I find it relevant to know the feedback-free CO2 doublings, that pure CO2 effect has a factor 9,25 between total and one doubling effect. I find it relevant to know that its the last 10,8% of the pure Co2 effect (the present doubling) that is supposed to make temperatures go bananas unlike the other doublings.
This concept that the particular doubling around 3-4-5-6-700 ppm CO2 should warm the Earth much more than other doublings (which has not been argued against?) is shown by nature to be unlikely.
Why? Because we are in an interglacial, that is, an unusual temperature max. The last many times we have had this warm temperature, nature has not been able to get any warmer.
Therefore, a little heat from CO2 right now is in fact very unlikely to make temperatures boom. If 1 K more heat should have mad temperature rise 6K – like Hansen suggests – then why have this not happened before at any other interglacial?
With all the warm interglacials we have natures full scale experimental data just in front of our eyes. And never in the interglacials did a temperature lift of one degree celcius lead to 6K temp lift. Therefore Hansens (and IPCC´s) claims appears not supported by data. Or?
K.R. Frank