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From: Don Klipstein on 17 Dec 2008 22:30 In article <apktj45jhkb21sq5iv56nbcjgl33a84l4t(a)4ax.com>, Whata Fool wrote: >don(a)manx.misty.com (Don Klipstein) wrote: > >>In <pan.2008.12.02.00.19.03.512271(a)REMOVETHISix.netcom.com>, Bill Ward >>wrote: >>>On Mon, 01 Dec 2008 08:59:25 +0000, Don Klipstein wrote: >>> >>>> In <pan.2008.11.29.04.28.21.555150(a)REMOVETHISix.netcom.com>, Bill Ward >>>> said: >>>>>On Fri, 28 Nov 2008 17:38:49 -0800, bill.sloman wrote: >>>>> >>>>>> On 28 nov, 19:01, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>>> On Fri, 28 Nov 2008 05:54:19 -0800, bill.sloman wrote: >>>>>>>> On 27 nov, 19:38, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>>>>> On Thu, 27 Nov 2008 06:55:09 -0800, bill.sloman wrote: >>>> <SNIP stuff already said more than 6 times> >>>>>>>>>> I thought I'd covered that. In the near and middle infra-red both >>>>>>>>>> water and carbon dioxide have spectra that consist of a lot of >>>>>>>>>> narrow absorbtion lines - rotational fine structure around a few >>>>>>>>>> modes of vibration. >>>>>>> >>>>>>>>>> Only a few of these lines overlap, so to a first approximation the >>>>>>>>>> greenhouse effects of carbon dioxide and water are independent. >>>>>>>>>> Water doesn't mask CO2 absorbtions and an vice versa. >>>>>>> >>>>>>>>>> The situation gets more complicated when you look at the widths of >>>>>>>>>> the individual absorption lines. These are broader in the >>>>>>>>>> atmosphere than they are when looked at in pure sample of water >>>>>>>>>> vapour or carbon dioxide in the lab, which increases the greenhouse >>>>>>>>>> effect. >>>>>>> >>>>>>>>>> The mechanism of this "pressure broadening" is intermolecular >>>>>>>>>> collisions that coincide with the emission or absorbtion of a >>>>>>>>>> photon - this slightly changes the molecule doing the >>>>>>>>>> absorption/emission, slightly moving the position of the spectal >>>>>>>>>> line. >>>>>>> >>>>>>>>>> Polar molecules - like water and carbon dioxide - create more >>>>>>>>>> pressure broadening than non-polar molecules than oxygen and and >>>>>>>>>> nitrogen. They interact more strongly with the molecules they >>>>>>>>>> collide with - creating a bigger spectra shift - and the collision >>>>>>>>>> lasts longer. >>>>>>> >>>>>>>>>> So more carbon dioxide in the atmosphere makes water a more >>>>>>>>>> powerful green-house gas and vice versa. >>>>>>> >>>>>>>>>> Happy now? >>>>>>> >>>>>>>>> No, you just spewed the dogma again.  I think the troposphere is >>>>>>>>> there because of convection lifting the surface energy up to the >>>>>>>>> cloud tops, maintaining a near adiabatic lapse rate. >>>>>>> >>>>>>>> Convection becomes progressively less effective as the pressure drops >>>>>>>> - gas density decreases with pressure, which decreases the driving >>>>>>>> force you get from a given temperature difference in exactly the same >>>>>>>> proportion, and the quantity of heat being transported per unit >>>>>>>> volume is also reduced. >>>>>>> >>>>>>> So the gas is expanding.  It's still rising, and the resistance is >>>>>>> decreased.  Lift is roughly constant at least to 14000 ft, from >>>>>>> personal observation. It doesn't generally drop off linearly with >>>>>>> altitude. >>>>>> >>>>>> But it is less dense, so it's transporting less heat. >>>>> >>>>>Energy is conserved. Where did the latent heat go, if not up? It's >>>>>carried by convection to the cloud top, and radiates away. >>>> >>>> Not all of it (latent or the majority otherwise) does. >>> >>>Then I repeat: Where did it go? Surely you're not claiming net energy is >>>moving from cold air to warm surface. The second law cops will come >>>and get you. >> >> Some gets radiated. Much ends up on surface farther from the tropics >>than where it came from. A little bit does end up on surface hotter than >>where it came from (in dry subtropical highs), but that is clearly greatly >>a minority. > > I'm not sure where Bill thinks the latent heat goes, but if >the water vapor condenses in or near the top of a cloud, all the latent >heat goes to warming the air that cooled it enough to condense, or if >cold black sky caused the water vapor to condense, the latent heat goes >to the surrounding air any way. > > Latent heat doesn't end up warming a surface does it, what kind >of surface would be cool enough to condense water vapor other than the >inside of windows? How about everywhere where dew and frost forms. A significant portion of ice accumulation in Antarctica is from frost. Meanwhile, latent heat released in rising air makes the air warmer where it descends than it would otherwise be. That accounts for part of the heat transfer from the tropics to the poles via global atmospheric circulation. - Don Klipstein (do(a)misty.com)
From: Don Klipstein on 17 Dec 2008 22:35 In article <pan.2008.12.09.23.10.19.953635(a)REMOVETHISix.netcom.com>, Bill Ward wrote: >On Tue, 09 Dec 2008 15:26:27 -0500, Whata Fool wrote: > >> don(a)manx.misty.com (Don Klipstein) wrote: >> >>>In <pan.2008.12.02.00.19.03.512271(a)REMOVETHISix.netcom.com>, Bill Ward >>>wrote: >>>>On Mon, 01 Dec 2008 08:59:25 +0000, Don Klipstein wrote: >>>> >>>>> In <pan.2008.11.29.04.28.21.555150(a)REMOVETHISix.netcom.com>, Bill Ward >>>>> said: >>>>>>On Fri, 28 Nov 2008 17:38:49 -0800, bill.sloman wrote: >>>>>> >>>>>>> On 28 nov, 19:01, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>>>> On Fri, 28 Nov 2008 05:54:19 -0800, bill.sloman wrote: >>>>>>>>> On 27 nov, 19:38, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>>>>>> On Thu, 27 Nov 2008 06:55:09 -0800, bill.sloman wrote: >>>>> <SNIP stuff already said more than 6 times> >>>>>>>>>>> I thought I'd covered that. In the near and middle infra-red >>>>>>>>>>> both water and carbon dioxide have spectra that consist of a lot >>>>>>>>>>> of narrow absorbtion lines - rotational fine structure around a >>>>>>>>>>> few modes of vibration. >>>>>>>> >>>>>>>>>>> Only a few of these lines overlap, so to a first approximation >>>>>>>>>>> the greenhouse effects of carbon dioxide and water are >>>>>>>>>>> independent. Water doesn't mask CO2 absorbtions and an vice >>>>>>>>>>> versa. >>>>>>>> >>>>>>>>>>> The situation gets more complicated when you look at the widths >>>>>>>>>>> of the individual absorption lines. These are broader in the >>>>>>>>>>> atmosphere than they are when looked at in pure sample of water >>>>>>>>>>> vapour or carbon dioxide in the lab, which increases the >>>>>>>>>>> greenhouse effect. >>>>>>>> >>>>>>>>>>> The mechanism of this "pressure broadening" is intermolecular >>>>>>>>>>> collisions that coincide with the emission or absorbtion of a >>>>>>>>>>> photon - this slightly changes the molecule doing the >>>>>>>>>>> absorption/emission, slightly moving the position of the spectal >>>>>>>>>>> line. >>>>>>>> >>>>>>>>>>> Polar molecules - like water and carbon dioxide - create more >>>>>>>>>>> pressure broadening than non-polar molecules than oxygen and and >>>>>>>>>>> nitrogen. They interact more strongly with the molecules they >>>>>>>>>>> collide with - creating a bigger spectra shift - and the >>>>>>>>>>> collision lasts longer. >>>>>>>> >>>>>>>>>>> So more carbon dioxide in the atmosphere makes water a more >>>>>>>>>>> powerful green-house gas and vice versa. >>>>>>>> >>>>>>>>>>> Happy now? >>>>>>>> >>>>>>>>>> No, you just spewed the dogma again.  I think the >>>>>>>>>> troposphere is there because of convection lifting the surface >>>>>>>>>> energy up to the cloud tops, maintaining a near adiabatic lapse >>>>>>>>>> rate. >>>>>>>> >>>>>>>>> Convection becomes progressively less effective as the pressure >>>>>>>>> drops - gas density decreases with pressure, which decreases the >>>>>>>>> driving force you get from a given temperature difference in >>>>>>>>> exactly the same proportion, and the quantity of heat being >>>>>>>>> transported per unit volume is also reduced. >>>>>>>> >>>>>>>> So the gas is expanding.  It's still rising, and the >>>>>>>> resistance is decreased.  Lift is roughly constant at least >>>>>>>> to 14000 ft, from personal observation. It doesn't generally drop >>>>>>>> off linearly with altitude. >>>>>>> >>>>>>> But it is less dense, so it's transporting less heat. >>>>>> >>>>>>Energy is conserved. Where did the latent heat go, if not up? It's >>>>>>carried by convection to the cloud top, and radiates away. >>>>> >>>>> Not all of it (latent or the majority otherwise) does. >>>> >>>>Then I repeat: Where did it go? Surely you're not claiming net energy >>>>is moving from cold air to warm surface. The second law cops will come >>>>and get you. >>> >>> Some gets radiated. Much ends up on surface farther from the tropics >>>than where it came from. A little bit does end up on surface hotter than >>>where it came from (in dry subtropical highs), but that is clearly >>>greatly a minority. >> >> >> >> I'm not sure where Bill thinks the latent heat goes, > >It's radiating to space. It may take a while, but it really has no >choice. Heat can't go against a temperature gradient unless it's pumped, >and the surface is warmer than the tropopause. If the atmosphere is transparent to all wavelengths of concern, then the surface can cool by radiation while all air above it is warmer. Though I would expect windy days to cause "forced convection" establishing a tropopause at some low altitude (a kilometer or two) with temperature cooler than daily high surface temperature. >> but if >> the water vapor condenses in or near the top of a cloud, all the latent >> heat goes to warming the air that cooled it enough to condense, or if cold >> black sky caused the water vapor to condense, the latent heat goes to the >> surrounding air any way. >> >> Latent heat doesn't end up warming a surface does it, what kind >> of surface would be cool enough to condense water vapor other than the >> inside of windows? > >Anything below the dew point? Rather common on Earth's surface actually so far when the sun is down. Also common in colder polar areas - frost is a significant factor for maintaining the ice sheets of Greenland and Antarctica. - Don Klipstein (don(a)misty.com)
From: Don Klipstein on 17 Dec 2008 23:51 In <pan.2008.12.09.17.07.31.717807(a)REMOVETHISix.netcom.com>, B. Ward wrote: >On Tue, 09 Dec 2008 06:26:15 +0000, Don Klipstein wrote: > >> In <pan.2008.12.01.17.08.14.877184(a)REMOVETHISix.netcom.com>, Bill Ward >> wrote: >>>On Mon, 01 Dec 2008 08:29:43 +0000, Don Klipstein wrote: >>> >>>> In article <pan.2008.11.27.18.38.37.222361(a)REMOVETHISix.netcom.com>, >>>> Bill Ward wrote: >>> >>><big snip of old post> >>> >>>>> I think the troposphere is there >>>>>because of convection lifting the surface energy up to the cloud tops, >>>>>maintaining a near adiabatic lapse rate. Radiative transfer is blocked >>>>>by GHG's, and plays little part below the tropopause. Radiation models >>>>>are thus largely irrelevant. >>>> >>>> The lapse rate is well short of adiabatic in much of the world, >>>> especially much of the time where surface albedo is prone to change >>>> from temperature change. Those parts of the world have upward mobility >>>> in surface temperature. >>> >>>Can you explain more clearly what you mean and the physical mechanisms >>>involved? >> >> Much of the atmosphere has horizontal temperature gradient. That causes >> a tendency for tropical air from generally roughly the 500-200 mb level or >> so to push poleward and polar air generally below roughly the 500 mb or >> 600 mb so level to push equatorward. That alone reduces the lapse rate in >> much of the troposphere, especially in areas ahead of warm fronts. > >OK, thanks. I think I see the problem. First, any movement caused by >density difference has to be gravitational in origin. Second, the >applicable lapse rate is along the path of motion - what the air actually >sees, not necessarily vertical. So the nearly horizontal motion is still >convective, it's just that the effective lapse rate is due to latitude >differences, not altitude differences. The cold air displaces the warm >air upwards - that's still convection, even though the motion is largely >horizontal. That is indeed true. >Note the warm wet air still ends up at a higher colder altitude, no matter >how far north it has to go. The latent heat has been lifted by the cold >air sliding underneath it. > >It may help to visualize putting large air dams around the Earth at >the tropic boundaries, allowing the system to come to equilibrium >temperatures, then removing them. The cold polar air would flow under the >hot tropicel air. Yes, that is true. And some of the heat transported polewards by this circulation is latent heat and some is not. >> Also, ice-covered areas and polar areas in winter tend to receive >> little sunlight and radiate away heat advected in from elsewhere. The >> surface will cool less than air higher up that is also receiving >> advected heat. >> >>> It appears to me they would still cool faster from increased >>>convection, >> >> Although if surface warming is the cause of the increased convection, >> the increase in convection merely slows down the heating. There are >> plenty of areas where the surface has to heat a lot before convection >> results. > >It's the integral heat loss from all the places that cool that counts. >Places that don't cool much don't count as much. Although lower elevations in polar regions are doing a lot of cooling - they receive warmth from more-equatorward latitudes and get rid of that heat by radiation. With less water vapor overhead, polar regions have good radiational cooling of surface and lowest tropoaphere. >>> unless you're talking about places that are already cold, and >>>thus don't do much cooling. >> >> I was including those. They do cool the atmosphere, which receives >> heat from air coming in from warmer areas. If GHGs are increased, >> they will cool the atmosphere less and be warmer. If they lose ice >> cover and/or gain water vapor overhead from warming, then there is >> positive feedback for warming. > >The smaller area and low sun angle would seem to diminish that effect >compared to the large area and overhead sun in the tropics. It's that >integral thing again. Though the polar areas have low sun angle and less insolation than the tropics, insolation at the polar regions is still significant. "Raw insolation" (my words, for neglecting of atmospheric blockage of solar radiation) is about 40% as great at the poles as at the equator. Such "raw insolation" at the poles actually exceeds that of the peak for the equator 20% of the year! As for actual annual average insolation after atmospheric effects including clouds - the most-insolated areas on a particular global map achieve 280-300 watts, and the least-insolated areas achiece 60-80 watts. Most area more poleward than the coldest-cloudiest areas achieve the 80-100 watt range. A few spots achieve 100-120 watts more poleward than part of the lowest 60-80 watt level. Lower of the 2 global maps in: http://en.wikipedia.org/wiki/File:Insolation.png Yet, the polar areas have radiation balance being cooling (and tropical areas have radiation balance being heating), in order to drive global circulation in the atmosphere and in the oceans that transports heat from the tropics to the polar regions. >>>> Should the arctic and antarctic warm, then global convection from >>>> the >>>> tropics to the arctic and antarctic will slow down until the tropics >>>> warm - though I still expect the arctic and antarctic (especially the >>>> arctic) to warm more than the tropics. >>> >>>Why would the polar regions warm, when they already don't receive enough >>>heat from the sun to maintain their existing temperature? Again, your >>>causality seems backward. >> >> They maintain temperature that sunlight is insufficient to maintain >> because warmer air comes in from elsewhere. The polar regions cool the >> atmosphere in the global convection scheme, and the tropics warm it. > >But in the IR radiation cooling scheme, the hot tropics cool far more than >the already cold poles. I would like to add: The tropical deep convection with tall deep cloud where the air rises, especially in the ITCZ which is a major part of global atmospheric circulation, has the cloud tops at a very high level and very cold, and atmospheric temperature elsewhere in the world at the same pressure level is majority warmer. Much of the air rising high in the ITCZ even warms by radiation after rising so much to get so cold - and descends at a rate slowed/limited by its ability to radiate heat - it does much of its cooling where it descends. >> If the polar regions gain GHGs and/or lose ice cover (to increase >> reception of sunlight), then they will be warmer than otherwise. >> Decrease in horizontal temperature gradient will reduce the "global >> convection from tropics to poles" (which is advection - heat transport >> by largely horizontal movement of air or ocean). If that decreases, the >> tropics will warm slightly and partially restore "global convection". >> >>>> I do expect much warming in the portions of the world where there is >>>> usually convection or lapse rate just short of causing convection to >>>> depend on global albedo change - which is actually occurring, and >>>> expected to occur as global warming causes loss of snow and ice cover. I think I misspoke/typo-ed there - I expect the warming to be concentrated to areas where the lapse rate has upward mobility. That includes areas where snow/ice cover is subject to change. >I must admit, it's hard for me to get excited by the change in albedo from >ice melting at the cold poles when I look at a satellite image of the >worldwide cloud cover over the hot areas of the world. It doesn't look >like it would take much increase in clouds to make up for ice melting. Except I see no trend of global warming to increase clouds. In fact, if vertical convection increases, I don't see increase in cliud cover - possibly even a decrease. The within-cumulus-cloud updrafts would intensify with more water vapor to work with, and I expect that to hold true to an extent reducing ratio of updraft area to downdraft area in convective areas that have both. Most of the downdraft in convective areas is outside the cumulus clouds - clear air. Convective areas with great cloud cover over a region tend to be tropical hotspots that have updraft being majority of regional air movement, as part of global atmospheric circulation. If the globe warms and increased presence of water vapor occurs, I expect such tropical convective hotspots to get more efficient - and their cloud cover area to actually shrink from their efficiency outpacing need to transport heat from the tropics to the polar regions (especially since part of the polar regions will respond to increase of GHGs by increase of absorption of solar radiation). >>>> Furthermore, much of the actual problems to result from global >>>> warming >>>> is from loss of snow and ice cover - and most of that is in parts of >>>> the world where the lapse rate from surface to tropopause is mostly >>>> far short of producing thunderstorms. > >And thus not all that important to the actual cooling processes. Those regions actually have radiation balance being cooling - with cooling disproportionately from surface and lower altitudes of the atmosphere - assisted by below-worldwide-average presence of GHGs overhead, due to less water vapor overhead. Those regions having radiation balance achieving cooling is what drives the atmospheric and oceanic global circulations that make most of the tropical areas cooler than they would be by radiation balance alone, and most polar and near-polar areas warmer than they would be by radiation balance alone. >>>The polar regions must receive additional heat from low latitudes to >>>keep from getting colder. Convective heat flow tends to equalize >>>temperatures, unless weather is somehow immune to the second law. >> >> Polar regions do indeed receive heat from lower latitudes - from air >> movement mostly within 1 degree of horizontal, with lapse rate mostly >> short of causing vertical convection. >> >>>> Radiative transfer is actually significant within the troposphere. >>>> Radiative transfer can easily involve repeated absorption and emission >>>> of photons along the way, such as (for extreme example) within the >>>> "radiative layer" of the Sun. That excluding the core is a layer over >>>> 100,000 km thick, and most of the heat produced by the sun is produced >>>> in the core and has to pass through the core-exluding portion of the >>>> "radiation zone", there is no convection, and most radiation gets >>>> absorbed before going mere micrometers. >>> >>>The Sun is operating at considerably higher pressures and temperatures >>>than the Earth. Can't you find a more relevant and convincing >>>explanation that includes convection? >> >> GHG presence in Earth's atmosphere is great enough for radiation from >> the surface to often be absorbed and re-emitted a few times before >> geting to outer space. At night, radiation is largely how the surface >> cools. Increasing GHGs will increase the number of times radiation will >> be absorbed and re-emitted before getting to space, with more chances >> for the radiation to be re-radiated downward. Increase of GHGs will >> impede radiational cooling of the surface, and make the surface get a >> warmer head start for the next day. > >I think that is one of the major sources of confusion, and needs to be >explained. Assume a layer of pure CO2 at some temperature, in a stable >non-turbulent atmosphere. Illuminate it with in-band IR from the bottom >and watch what happens. The lower layer will absorb the IR, and get >warmer. The hot gas will convect up and share it's energy with other CO2 >molecules. At equilibrium, the layer of CO2 will be warmer, and, as >all warm CO2 will do, radiating IR from the top at the new temperature. >What goes on radiatively (or convectively) inside the gas is immaterial. >It's just hot gas. It doesn't know or care how it was heated. > >EM travels at c. It doesn't matter how many times it's "absorbed and >re-radiated", it still just heats the gas. The only way energy can be >"trapped" in the gas is to raise it's temperature. > >Now if I have any major misconceptions about IR and CO2, I'm sure you'll >take this opportunity to straighten me out. At this point, I would like to point out that even though radiation travels at c divided by refraction index (close enough to 99.9% of c for most of earth's atmosphere), absorption leading to requirement for reradiation easily enough gets into time constants of several days - GHGs below at least half the air mass of the stratosphere are in good enough thermal contact with N2 and O2, where there is significant storage of heat (or lack thereof), and to a significant extent moving to somewhere else (in latitude or altitude or both) where temperature and radiation balance were not the same as several hours or a couple days before. >>>> Likewise, the Earth's surface receives significant radiation from >>>> clear air below the 500 millibar level. >>> >>>Not more than it radiates, unless the WV is warmer than the surface. The >>>Second law won't allow it. (OK, very very rarely by quantum theory.) >>> But no actual radiative heating unless the source is hotter than the >>>target. Net heat flow is from the surface to space. >> >> Less than it radiates - but enough to slow surface cooling. > >Of course. Thats just another way of expressing the Stephan-Boltzmann >equation. It's simpler for me to understand if I look at the net flux by >considering the target temperature rather than assuming both are radiating >to 0K, then subtracting. It's easier to avoid inadvertent 2nd law >violations. It is not a 2nd law violation for some layer of atmosphere above the surface to increase absorption of radiation from the surface and to re-radiate half of that back towards the surface so as to warm the surface, as long as the responsible atmospheric layer is cooler than the newly-warmed surface temperature (especiaslly if also colder than the colder old surface temperature) and the surface remains cooler than the Sun. <I snip from here :) > - Don Klipstein (don(a)misty.com)
From: Don Klipstein on 18 Dec 2008 00:11 In <pan.2008.12.10.17.12.59.237655(a)REMOVETHISix.netcom.com>, B. Ward wrote: >On Wed, 10 Dec 2008 05:25:46 -0800, bill.sloman wrote: > >> On 9 dec, 18:07, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>> On Tue, 09 Dec 2008 06:26:15 +0000, Don Klipstein wrote: >>> > In <pan.2008.12.01.17.08.14.877...(a)REMOVETHISix.netcom.com>, Bill Ward >>> > wrote: >>> >>On Mon, 01 Dec 2008 08:29:43 +0000, Don Klipstein wrote: >>> >>> >>> In article <pan.2008.11.27.18.38.37.222...(a)REMOVETHISix.netcom.com>, >>> >>> Bill Ward wrote: >> >> <snip> >> >>> > GHG presence in Earth's atmosphere is great enough for radiation >>> > from the surface to often be absorbed and re-emitted a few times >>> > before getting to outer space. At night, radiation is largely how >>> > the surface cools. Increasing GHGs will increase the number of times >>> > radiation will be absorbed and re-emitted before getting to space, >>> > with more chances for the radiation to be re-radiated downward. >>> > Increase of GHGs will impede radiational cooling of the surface, and >>> > make the surface get a warmer head start for the next day. >>> >>> I think that is one of the major sources of confusion, and needs to be >>> explained. Assume a layer of pure CO2 at some temperature, in a stable >>> non-turbulent atmosphere. Illuminate it with in-band IR from the >>> bottom and watch what happens. The lower layer will absorb the IR, and >>> get warmer. The hot gas will convect up and share it's energy with other >>> CO2 molecules. At equilibrium, the layer of CO2 will be warmer, and, >>> as all warm CO2 will do, radiating IR from the top at the new >>> temperature. What goes on radiatively (or convectively) inside the gas >>> is immaterial. It's just hot gas. It doesn't know or care how it was >>> heated. >> >> You miss the point that the top of the CO2 layer is going to be cooler >> than the bottom. Where there's an energetically significant difference in >> pressure between the top and the bottom (as there is in the troposphere) >> you can rely on non-radiative mechanisms to maintain this difference. > >That would be convection, as I mentioned. > >> The CO2 molecules at the bottom of the layer are radiating at the >> intensity and energy distribution across the active lines in the spectrum >> that matches the higher temperature at the bottom of the layer. >> >> By the time the radiation has been absrobed and re-emitted a couple of >> times on the way up, it has been re-emitted from cooler molecules, and >> there's less of it - as you have pointed out, the power radiated per >> molecule (and there are fewer of them at the top of the layer) is >> proportional to the fourth power of temperature, and more is being emitted >> at longer wavelengths. >> >>> EM travels at c. It doesn't matter how many times it's "absorbed and >>> re-radiated", it still just heats the gas. The only way energy can be >>> "trapped" in the gas is to raise it's temperature. >> >> Half the re-radiated energy goes back the way it came, Every time a photon >> is absorbed - as opposed to scattered - the energy is distributed amongst >> all the degrees of freedom available to the molecule, including rotation >> and translation. All of this means that the infra-red radiation coming out >> of the top of the layer carries aappreciably less energy than the >> infra-red radiation that was absorbed at the bottom of the layer. > >Do you have some waiver freeing you from the conservation of energy? I >specified "at equilibrium". It seems to me that guarantees the incoming >and outgoing energy is equal. > >>> Now if I have any major misconceptions about IR and CO2, I'm sure >>> you'll take this opportunity to straighten me out. > >> To try an straighten you out ... > >Where did the missing energy go? Increasing absorption/re-emission of thermal radiation in the atmosphere does not have any energy missing - what happens is that the balances and the transports change. If the balances require temperature change to be maintained, then the temperature accordingly changes where it has to change to maintain energy outgo equalling energy income both locally and globally. One thing that increase of GHGs is good for is increase of convection - and not all of it vertically, but some of it in the form of "global atmospheric circulation" - much of that is within a degree of horizontal! Such "global circulation" transports heat from the tropical areas to the polar areas. Any increase of that would warm the polar areas, and make them darker due to being less-covered by ice and snow - although disproportionate warming of such polar areas would impair "global circulation" until the tropics warmed. I expect that if an increase of GHGs warmed the globe, then polar regions (primarily in the northern hemisphere where snow/ice cover has more mobility to change) would warm more than the tropics, whether global atmospheric circulation increases or decreases. Global warming should accomplish both increase of "global atmospheric circulation" and decrease of temperature difference between equator and poles, although one feedback mechanism (surface albedo) is positive for global temperature change and negative for "global circulation" varying with global temperature change. - Don Klipstein (don(a)misty.com)
From: Don Klipstein on 18 Dec 2008 00:29
In <pan.2008.12.09.17.20.42.535715(a)REMOVETHISix.netcom.com>, B. Ward wrote: >On Tue, 09 Dec 2008 06:33:06 +0000, Don Klipstein wrote: > >> In <pan.2008.12.02.04.09.57.211078(a)REMOVETHISix.netcom.com>, Bill Ward >> wrote: >>>On Tue, 02 Dec 2008 00:14:02 +0000, Don Klipstein wrote: >>> >>>> In <pan.2008.11.23.15.47.04.647543(a)REMOVETHISix.netcom.com>, Bill Ward >>>> wrote in part: >>>>> >>>>>Wrong fiasco. I meant this one: >>>>> >>>>>http://www.denisdutton.com/cooling_world.htm >>>> <SNIP> >>>>>Here's the original, with graphics: >>>>> >>>>>http://denisdutton.com/newsweek_coolingworld.pdf >>>>> >>>>>> but subsequent observations doesn't suggest that it is to slowing >>>>>> down any more. >>>>>> >>>>>> Do try to get your facts right. >>>>> >>>>>Right about now, you should be feeling a bit foolish. >>>> >>>> Check out HadCRUT-3v - good enough for The Register! >>>> >>>> Graph: >>>> >>>> http://www.cru.uea.ac.uk/cru/climon/data/themi/g17.htm >>>> >>>> Data in text form: >>>> >>>> http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3vgl.txt >>> >>>It's all depends on how you pick your data: >>> >>>http://www.worldclimatereport.com/wp-images/loehle_fig2.JPG >> >> Eeyore likes to post that one as a binary attachment in this newsgroup >> (though I'm not saying that's where he got it from). The paper it comes >> from has a link to the data in text form for that one - ending with 1980. >> >> The paper that comes from also has a "corrected global temperature >> reconstruction" ending much earlier - I forget for the moment whether 1920 >> or 1930. Splice HadCRUT-3 global or HadCRUT-3v global (smoothed) onto >> that at any year covered by both Loehle's "corrected global temperature >> reconstruction" and HadCVRUT and it looks like we are now warmer than peak >> of MWP. >> >>>http://www.climateaudit.org/?p=2400 >> >> Points to Loehle. > >http://www.climateaudit.org/?p=4475 I took about a minute there, and so far it appears to depend on Loehle. Dependence on Loehle over other sources of historical temperature data depends on tree rings being inaccurate over centuries despite giving good indication on shorter time scales. My argument is not that Loehle waas wrong to exclude tree rings, but that Loehle fails to show height of MWP to be warmer than our world is now. The most-Google-findable publication by Loehle with search terms including his name and "tree rings" in my experience is a publication that appears to me to be not 1 but 2. Often-mentioned-in-this-newsgroup is one graph in the first one, with omission of link to a data file largely in text format and notably ending with 1980 - and the globe has warmed quite a bit since. The second part has Loehle publishing a "Corrected Global Temperature Reconstruction". I invite anyone to splice smoothed-global-temperature according to smoothed-global either HadCRUT-3 or HadCRUT-3v anywhere those and Loehle's "Corrected Global Temperature Reconstruction" both exist (1852-1920), and see what we got! >This is also kind of interesting. > >ClimateAudit seems a bit more credible to me than RealClimate for some >reason. I manage to argue with low reliance on RealClimate - I even argue with data presented by The Register! - Don Klipstein (don(a)misty.com) |