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Post by northsphinx on Mar 22, 2010 17:04:20 GMT
Is a book written by sir John Houghton tinyurl.com/yl8oohcI found it very interesting and want to share some of the text in it. As page 14 in 2.3: "The tropopause is a surface situated a a height of ~10 km in mid latitudes which divides the region below ( the troposphere), in which convection is the dominant mechanism of vertical heat transfer, from the stratosphere which is much more stable stratified and where radiative transfer is dominant." Convection. NOT radiation. 4.8 ".... in the 20-60 km region. In this part of the atmosphere the temperature distribution is mainly determined by a balance between radiative cooling in the infrared from carbon dioxide band and heating by absorption of solar radiation by ozone." more CO2 COOLS the stratosphere and by that the earth.
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Post by socold on Mar 22, 2010 22:53:39 GMT
Cooling in the stratosphere? who would have thought that...
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Post by nautonnier on Mar 23, 2010 1:30:31 GMT
Is a book written by sir John Houghton tinyurl.com/yl8oohcI found it very interesting and want to share some of the text in it. As page 14 in 2.3: "The tropopause is a surface situated a a height of ~10 km in mid latitudes which divides the region below ( the troposphere), in which convection is the dominant mechanism of vertical heat transfer, from the stratosphere which is much more stable stratified and where radiative transfer is dominant." Convection. NOT radiation. 4.8 ".... in the 20-60 km region. In this part of the atmosphere the temperature distribution is mainly determined by a balance between radiative cooling in the infrared from carbon dioxide band and heating by absorption of solar radiation by ozone." more CO2 COOLS the stratosphere and by that the earth. Northsphinx - Yes Convection is the dominant transmission of heat in the troposphere, that is why the IPCC _deliberately_ discard it in their definitions of radiative forcing. The definition of radiative forcing requires a slab unresponsive atmosphere - ie no convection. Yet it is on this unreal construct that AGW rests. I have repeatedly said this and steve and SoCold still dutifully return to their hypothetical 3.7 watts per square meter forcing for a doubling of CO 2 - even though neither of them can say where those square meters are measured. The tropopause (top of the troposphere - from the Greek Tropos - to turn or move) is the top of the convection. And in the tropics the tropopause can be 15km and at the poles 6 - 7km - rather obviously the stronger the convection the higher it rises. Humid air is lighter than dry air Humid air has ~80 times the heat content of dry air Humid air rises and as it does so the water in it condenses and warms the air further This is called the wet adiabatic lapse rate Eventually at or below the tropopause the resulting energy will radiate out to space through the remaining layers of the atmosphere. But that heat has bypassed the denser layers in which CO 2 scatters some infra-red and will not be further impeded The hydrologic cycle would continue if magically all the CO 2 disappeared. But it is incorrectly considered ' only a feedback' to CO 2 'warming' by the AGW proponents and disregarded. I think this is because it is so much easier for mathematicians to use simple radiative algorithms than to understand then model the chaotic fluid flows and varying humidities in the real atmosphere.
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Post by hunter on Mar 23, 2010 2:00:08 GMT
nautonnier, Please explain how dry air can be heavier than humid air?
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Post by nautonnier on Mar 23, 2010 2:20:02 GMT
Strangely this was recently described well in an answer in New Scientist: "A water molecule, H2O, has a molecular weight of 18. Air consists of approximately 79 per cent nitrogen, N2, of molecular weight 28, and 21 per cent oxygen, O2, with a molecular weight of 32. So air's effective average molecular weight is 28.84, much greater than water's 18.
From the ideal gas law, at a given pressure and temperature the number of molecules of gas in a given volume is constant, so if in humid air some of those molecules are water molecules, with their lower molecular weight, then humid air must have a lower density......
Although we might think of a gaseous water molecule as squeezing in between the air molecules and hence making the air denser, its actual effect is to force the air molecules apart to make space for itself. Only if the air were in a closed vessel would the evaporation of water cause it to become more dense, but then the pressure would rise too."www.newscientist.com/article/mg20527512.100-wet-wind.html
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Post by poitsplace on Mar 23, 2010 8:15:00 GMT
Cooling in the stratosphere? who would have thought that... LOL, but at no conceivable concentrations will this result in a bottleneck in radiative transfer. The stratosphere will remain hotter no matter what and therefore emit more radiation than the tropopause will ever send through it.
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Post by northsphinx on Mar 23, 2010 11:38:09 GMT
Agreed then? Heat transfer IN the troposphere is mainly due to convection. Heat loss= cooling from the stratosphere increase with more CO2. Now to the next important part: Heat loss from the earth surface and the troposphere to the cold space. All heat lost by radiation. And what does the sir of AGW state? In 4.11: "It also show that the outgoing long-wave radiation originates from near the surface or from cloud tops in the window region and from high in the troposphere in the strong carbon dioxide and water vapor bands" Hmm ;D Outgoing radiation at TOA originates from surface and cloud tops. And what about radiative properties of clouds? 6.5 by the way. "For consideration of the atmospheres radiation budget is it satisfactory to assume that all clouds except cirrus absorbs and emit terrestrial radiation as black bodies" That is a full spectrum! Not at all as CO2 with a narrow spectrum. And in 4.11 does the Sir of AGW state "No account have been taken of clouds and their radiative properties. Clouds are in fact probably the dominant influence in the radiative budget of the lower atmosphere but adequately taking them into account raises many problems" It is all about the clouds. OK so here do we have earth with about 50% cloud cover with an average outgoing IR originated from surface altitude and then a remaining BBR earth area from cloud top altitude. I guess the surface average altitude is easy to measure and is fairly constant but top of cloud is another matter. But it is a very large part of outgoing radiation origin since it may be considered as a black body. Also of big imortance is that the outgoing IR originated from CO2 is only from high altitude. Guess why? Since the heat transfer in the troposphere is mainly convection is the temperature in the troposphere also a function convection as well. That is CO2 temperature in the troposphere is a function of convection not radiative balance. It is also shadowed by vapor lifted by convection. Where vapor is not available in any larger amount will CO2 be "visible" again. That is in the stratosphere. But increased CO will there be increase cooling more than heating since the temperature difference is much larger to space than to earth. Net heat radiative transfer will always go from warm to cold. en.wikipedia.org/wiki/Second_law_of_thermodynamics
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Post by steve on Mar 23, 2010 14:56:51 GMT
I learnt two useful things in this thread.
1. The Swedish for "Page 14 is not shown in this preview".
2. If a page is missing from a google books preview in one locale, then looking at the same book on a different Google locale, you might be able to see it.
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Post by northsphinx on Mar 23, 2010 17:59:08 GMT
Here is more forgotten facts. Under this picture state Sir AGW: "Inspection of the spectrum of infrared radiation emitted outward by the atmosphere shown in the figure illustrates how remote temperature sounding is achieved, In the atmospheric window region between 800 and 950 cm-1, in the absence of clouds, the radiation originates mostly from the earths surface. Moving from the atmospheric window to smaller wave numbers, the mean absorption coefficient of carbon dioxide gradually increases so that the average level in the atmosphere being monitored moves up in altitude until th most absorbing region is reached- the Q branch near 667 cm-1- where the radiation largely originates in the stratosphere." In short: spectra of CO2 measured from space is from the stratosphere where co2 cool the earth. And there is more: In chapter 14.6 are "The enhanced greenhouse effect" discussed. "If the concentration of carbon dioxide doubles, the outgoing radiation from the wings of the carbon dioxide will originate from higher levels" "Because of the fall of the temperature with height these higher levels are cooler and therefore the amount of emitted radiation falls" And give an example of a double CO2 level will increase CO2 originated radiation average height with 3 km with 3 x lapse rate of 6 degrees C = 18 C lower temperature. Have the author not forgot a few thing in this so important statement? 1. Temperatures at this level in the troposphere is set by convection. By his own word. NOT a radiative balance. Increase or decreased radiation will not change the temperature in that part of the atmosphere. That is handled by convection. 2. 220 K is about the tropopause temperature. 3 km higher than 220 K is well into the stratosphere where according to wiki at least: "The Stratosphere is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler higher up and warmer farther down." So increased CO2 will increase outgoing radiation. To be continued...
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Post by steve on Mar 23, 2010 18:21:39 GMT
He didn't say that. He said that the radiation would originate from a higher layer on average, and that the higher layer is cooler so will radiate less. The temperature of the layer is still driven mainly by convection.
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Post by aj1983 on Mar 23, 2010 19:18:42 GMT
Haha, what I have learned from this topic is how to give a very ingenious spin to basic atmospheric physics. It is quite laughable. Keep up the good work .
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Post by nautonnier on Mar 23, 2010 19:32:16 GMT
Haha, what I have learned from this topic is how to give a very ingenious spin to basic atmospheric physics. It is quite laughable. Keep up the good work . It is sometimes good to get experts to return to the basics from the esoteric - they relearn things that they have forgotten. Remember the climate models _still_ do not model the hydrologic cycle well. They are trying but still cannot do it. A three body gravitational problem is easy in concept - but very difficult to model mathematically. So we have basic atmospheric physics showing that the majority of heat transfers to the tropopause by convection. But 'AGW atmospheric physics' and the IPCC definition of radiative forcing assuming that all heat gets to the troposphere by radiation from the surface. Perhaps re-learning basic atmospheric physics would be a good idea
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Post by aj1983 on Mar 23, 2010 19:42:39 GMT
You are correct in stating that the hydrologic cycle is not modeled well, it is the largest uncertainty in the AGW feedbacks.
Where did you find that the IPCC (which does not do research, but OK, that's something different) does not include convection, but only radiative transport?
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Post by northsphinx on Mar 23, 2010 20:59:29 GMT
It is direct quotes from THE book of sir AGW himself. Read it. It is quite fun.
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Post by northsphinx on Mar 23, 2010 21:30:02 GMT
He didn't say that. He said that the radiation would originate from a higher layer on average, and that the higher layer is cooler so will radiate less. The temperature of the layer is still driven mainly by convection. He writes in 14.6: "If therefore the concentration c is doubled, the origin of the radiation moves up to a level where the pressure is less by a factor of 2 e-05- about 3 km higher - where, assuming a lapse rate of 6 C/km the temperature on average will be about 18 degrees less. I f we assume the temperature of of 250 K for the undisturbed case, it will be 232 K in the doublet CO2 case. With this temperature difference the drop in radiation emitted within the spectral intervals 700-750 cm e-1 will be about 3 W/m2" Satellite measurement show us very clear that about 220K for undisturbed is the case not as assumed 250 K. That is about stratopause. The coldest place. Top of convection. In the stratosphere is temperature increasing with about 50 K in 40 km or 1,25 C/km. 3 km higher is nearly 4 degrees warmer. Not 18 degrees cooler.
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