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From: Don Klipstein on 14 Dec 2008 20:28 In article <sj0nj4t50ldoo8rn0pd2acu0pco441dhjg(a)4ax.com>, Whata Fool wrote: >don(a)manx.misty.com (Don Klipstein) wrote: > >>In article <pan.2008.11.29.05.49.04.133668(a)REMOVETHISix.netcom.com>, Bill >>Ward wrote: >>>On Fri, 28 Nov 2008 19:35:59 -0800, bill.sloman wrote: >>> >>>> On 28 nov, 14:20, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> wrote: >>>>> z wrote: >>>>> > and the fact that water vapor partial pressure rises with temperature, >>>>> > thereby making it an amplifier of other effects, such as CO2. >>>>> >>>>> An unproven hypothesis. i.e random noise. >>>> >>>> There's nothing unproven about the "hypothesis" that the partial pressure >>>> of water vapour in contact with liquid water rises with temperature. It's >>>> up there with Newton's law of gravity as one of the fundamental theories >>>> of science. >>>> >>>> And more water vapour does mean more pressure broadening in the carbon >>>> dioxide absorbtion spectrum. >>>> >>>> Carbonic acid (H2CO3) may not be stable in the vapour phase at room >>>> temperature, but it is stable enough that any collision between a water >>>> molecule and a carbon dioxide molecule lasts qute a bit longer than you'd >>>> calculate from a billiard-ball model. >>>> >>>> Eeyore's response isn't random noise either, though it's information >>>> content isn't any more useful - we already knew that Eeyore knows squat >>>> about physics, and he's long since made it clear than he doesn't realise >>>> how little he knows by posting loads of these over-confident and >>>> thoroughly absurd assertions. >>> >>>He may also be aware that increased water vapor lowers the condensation >>>altitude, >> >> Cloud bases lower if relative humidity rises. Relative humidity stays >>about the same if water vapor concentration is only commensurate with >>temperature rise. >> >>> raising the radiation temperature, and increasing the emitted IR >>>energy by the 4th power radiation law. IOW, it's a negative feedback, not >>>positive. >> >> Radiation from clud bases is toward Earth. >> >> Meanwhile, increasing GHGs cools the lower stratosphere and raises the >>tropopause - cloud tops around the tropopause will be cooler. >> >> - Don Klipstein (don(a)misty.com) > > > > If atmosphere radiates (the GHGs of it), in any direction, doesn't >that cool the part that radiates? It does increase radiational cooling of that little localized region of the atmosphere. It also increases radiational warming of same locality of the atmosphere from the surface and from GHGs elsewhere in the atmosphere. > When any part of the surface is above freezing, doesn't that surface >radiate more, and at the same time, evaporate more water, causing more >evaporative cooling. That part is true - warmer surface loses more heat by evaporative cooling and radiation than cooler surface. > And can the total picture of all radiation and evaporation mean >that the processes of cooling is dominant, only reducing when there is >less GHGs in the atmosphere. One complication to this is that the surface receives more radiation from GHGs than from GHG-free air. Another is that GHGs close to the surface not only radiate, but also receive radiation from the surface and from GHGs higher up. > Total water vapor in the atmosphere can change, and in ice ages >may gradually reduce, allowing more surface radiation to space, even >though there might be less atmosphere radiation to space. True. The ice ages over the past few hundred thousand years were marked by antarctic ice core records of reduced GHGs. > Has the total picture of the role of GHGs been thought out, with >an obvious cause of gradual deepening of ice age, and the sudden warming, >possibly caused by a minimum of GHGs (water vapor and CO2). > > Can we be certain that more GHGs (CO2) cause more warming, could >not less radiation to space by the atmosphere cause more warming? That would just reduce convection of the atmosphere, causing the surface temperature to be determined more by balancing incoming radiation to and outgoing radiation from the surface. That would actually make the surface colder than it is now. Consider that an atmosphereless blackbody sphere (suitably thermally conductive) in Earth's orbit would be cooler than Earth is, despite Earth having solar radiation absorption less than Earth's low temperature thermal IR emissivity. > Apparently atmospheric radiation is a big part of the total IR >radiation flux, and could that mean the atmosphere radiation controls >the temperature, not the surface radiation? If the atmosphere loses GHGs, then surface radiation controls the surface temperature more. If the atmosphere gains GHGs, then atmospheric radiation increases its effect on surface temperature. - Don Klipstein (don(a)misty.com)
From: Don Klipstein on 14 Dec 2008 21:52 In article <7qe9j4pkmasav75fpv4idfb0jc0mq89foo(a)4ax.com>, Whata Fool wrote: >Bill Ward <bward(a)REMOVETHISix.netcom.com> 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 That comes from a publication available at: http://www.ncasi.org/publications/Detail.aspx?id=3025 That is Fig. 1 on the 5th page (page 1052). Omitted is: "Data archived at http://www.ncasi.org/programs/areas/climate/LoehleE&E2007.csv" Which has the data ending with 1980. That publication, looks like a followup one by Loehle et. al. in the same PDF, has a "Corrected Global Temperature Reconstruction", which ends much earlier - apparently because not all his datasets go more recently than 1920. 18th page of the above PDF. Splice global smoothed HadCRUT-3 or -3v onto that one at any year both exist, and the result is we are now warmer than the peak of the MWP. >>http://www.climateaudit.org/?p=2400 Notably linking to "MBH98-style CIs for Loehle's reconstruction": http://signals.auditblogs.com/files/2007/11/l07.png Ending with 1980. The world has warmed about .35 degree C since 1980 according to smoothed HadCRUT-3 (as of 2-3 years ago), and by at least .3 degree C as of well into the 2008 dip according to smoothed HadCRUT-3v that The Register showed earlier this year in their "A Tale of Two Thermometers" article. http://www.cru.uea.ac.uk/cru/climon/data/themi/g17.htm > So much for "trends". :-) - Don Klipstein (don(a)misty.com)
From: Whata Fool on 14 Dec 2008 22:45 don(a)manx.misty.com (Don Klipstein) wrote: >In article <0qlej490u4g0mtol5r05fbmm4mn302jc15(a)4ax.com>, Whata Fool wrote: > >>>>>> Air would be warmer than present if there were no GHGs, >>>>>> that means, without question or need for further study, that >>>>>> GHGs cool the atmosphere. > >[snip] >> You are not following the present discussion, which up to here was >>related the my sentence just three attribution marks up, I repeat; >> >>"Air would be warmer than present if there were no GHGs, >>that means, without question or need for further study, that >>GHGs cool the atmosphere." >> >> This is more important to the premise of "GHGs hold the temperature >>thirty some-odd degrees warmer" than any other factor. > >[snip] > > However, a perfectly transparent non-radiating atmosphere would still >need its net heat transfer from the surface (including mountain surfaces) >to be zero in the long term, > or else there would be a long term trend of atmosphere temperature >changing unidirectionally. > > If convection is only intermittent (such as stopping when surface cools >at night), then lower atmosphere (except very closest to ground) would >have temperature determined more by daily high surface temperature than by >average surface temperature. Does that say that the temperature of the bulk of the atmosphere in that case would likely be higher than now? >>>Forced convection from wind turbulence would >>>result in a lapse rate towards a tropopause cooler than the surface. >> >> Perhaps cooler than the lower layer of air, but certainly not >>cooler than the average temperature of the surface. > > Easily cooler than the surface, since air there would only gain/lose >heat from/to the surface, and do so after warming from increased pressure >when convected to the surface. I estimate the warming would be a long term upward trend until a condition of net thermal transfer is reached over the year. The cooling effect would be greater where vertical circulation occurs, but I think the speed of sound would restrict the amount of circulation. >>> Modify that with clouds - clouds would radiate, with half the radiation >>>towards outer space, cooling the atmosphere, so the atmosphere would then >>>take heat from the surface by convection. >> >> You can't modify it with water clouds, there is no water on my >>GHG free planet, this is the GHG theory game, you must not pass GO, >>you go to jail if you do not stick to good physics and there are no >>"Get out of jail free" cards. > > Your water-free planet sounds like a cloudless one to me. Certainly, and I suppose it would have to be hydrogen free, else water would form. >>>> Actually, I don't see how the air could avoid getting warmer and >>>>warmer, because there is some amount of solar UV that is absorbed by >>>>the air, and would not be radiated away. >>> >>> That's pretty much above the tropopause. Earth even has a thermosphere, >>>with temperaturer higher than the surface temperature anywhere. >> >> And the reasons are? > > The thermosphere has density of GHGs so low as to have extremely low >ability to radiate anything at "ordinary atmospheric" temperatures. >However, it has significant absorption of the shortest wavelengths of UV >and of iozizing radiation. Doesn't that suggest that if the troposphere had no GHGs, it might have a temperature regime more like the thermosphere? (I have an opinion that infalling dust may add to the temperature of the upper atmosphere (there is a lot of it), but it may not be much of an effect). >> This discussion is about atmospheric temperatures, those are >>the temperatures used to calculate the annual global average temperatures! > > "Global average temperature" is, depending on determination, generally >supposed to be atmosphere either 4 feet or 2 meters above the surface. >However, a lot of "global average temperature" involves measurement of sea >surface temperature as opposed to that of the air either 4 feet or 2 >meters above. Isn't the GISS or IPCC "official" annual global average temperature derived from only high quality weather station locations? >>>> The failure of any counter argument to this is proof enough >>>>for me to show that all the AGW crowd is simply repeating the gossip >>>>or following the party line. >>>> >>>> Show me one case other than William Asher that even attempted >>>>to explain how the N2 and O2 could cool without GHGs. >>> >>> Portion below the tropopause would heat the surface and increase surface >>>radiation. There is also radiation from clouds. >>> >>> - Don Klipstein (don(a)misty.com) >> >> Gosh, is my "GHG Game" of a planet absent of GreenHouse Gas too >>difficult for educated people. >> >> There are no clouds, there is no water. >> >> On this planet the N2 and O2 atmosphere would be warmer than >>the real Earth. >> >> Start all over from the beginning. > > If we had a planet in Earth's orbit with thermal emissivity matching >absorption of solar radiation and a cloudless GHG-free atmosphere, average >surface temperature would be about 6 degrees C (279 K). How is this calculated, what cools the air that is warmed in daytime? > If we had a planet with albedo and surface thermal emissivity like those >of Earth and a cloudless GHG-free atmosphere, it would be much colder >still, since Earth's absorption of solar radiation is less than its low >temperature thermal radiation emissivity (due to absorption varying with >wavelength). > > Surface level atmosphere would have average temperature pretty close to >the surface temperature, since it can only gain heat from or lose heat to >the surface. > > - Don Klipstein (don(a)misty.com) I think it would be a very complex situation, sun facing mountain sides would surely be almost like wind tunnels during daytime, but down flow would be slower to develop. I am sure this is a question that demands further study, as it may very well mean that GHGs cool the atmosphere below what it would be without them. And that seems it could mean that GHGs cool the atmosphere, and that additional GHGs might cool it more.
From: Don Klipstein on 14 Dec 2008 22:49 In article <pan.2008.12.02.09.04.49.526817(a)REMOVETHISix.netcom.com>, Bill Ward wrote: >On Tue, 02 Dec 2008 05:55:11 +0000, Don Klipstein wrote: > >> In <pan.2008.11.26.21.17.23.310423(a)REMOVETHISix.netcom.com>, Bill Ward >> wrote: >>>On Wed, 26 Nov 2008 07:53:11 -0800, bill.sloman wrote: >>> >>>> On 26 nov, 12:28, Whata Fool <wh...(a)fool.ami> wrote: >>>>> Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> Â wrote: >>>>> >>>>> >bill.slo...(a)ieee.org wrote: >>>>> >>>>> >> You should note that the infra-red spectra of both carbon dioxide >>>>> >> and water vapour absorb are line spectra, and the lines aren't all >>>>> >> that wide (though this does depend on atmopsheric pressure and >>>>> >> temperature - search on "pressure broadening") and they don't >>>>> >> overlap to any great extent, which allows both gases to make >>>>> >> independent contributions to the greenhouse effect. >>>>> >>>>> Â Â Â Â Sloman resumes the AGW discussion of spectra, with >>>>> no numbers showing flux rates. Â Â Water vapor has some pretty >>>>> wide bands, CO2 much more narrow. >>>> >>>> In the near infra-red, which is the region of most interest for global >>>> warming, both carbon dioxide and water show line spectra. Both are >>>> triatomic molecules which means that they have symmetric and asymmetric >>>> stretches and a bending mode. Each of the vibrational lines shows >>>> rotational fine structure. The individual rotational lines are quite >>>> narrow (to an extent that depends on pressure broadening). >>>> >>>> Here's a high resolution study of the water vapour spectrum >>>> >>>> http://www.usu.edu/alo/lidarinfo/spie%204484.pdf >>>> >>>> both sets of spectra look something like a picket fence at the >>>> resolution you need to model the greenhouse effect. >>>> >>>>> >> There's also the point that the vapour pressure of water in the >>>>> >> stratosphere is pretty low, because the stratosphere is cold, and >>>>> >> carbon dioxide does more of the greenhouse work up there than it >>>>> >> does below the tropopause. >>>>> >>>>> Â Â Â Â Water has a very low boiling point in the >>>>> stratosphere because the pressure is low, does that make the vapor >>>>> pressure high or low? >>>> >>>> That's irrelevant - the temperature of the stratosphere is so low >>>> (-55C) that any water vapour around freezes to ice particles and the >>>> residual water vapour pressure is very low. >>>> >>>>> Â Â Â Â The stratosphere is cold, so the net energy >>>>> transfer from the surface to the stratosphere is upward, and the >>>>> energy transfer to space is great. >>>>> >>>>> Â Â Â Â AGW talkers completely leave out much of the >>>>> physics, gossip about spectra sounds mystical to the greenhorn >>>>> greenie, real physicists talk about energy transfer in flux quantities >>>>> per unit of time. >>>>> >>>>> Â Â Â Â The amount of CO2 in the stratosphere is minute, >>>>> because the stratosphere has a pressure of less than one pound per >>>>> square inch, and not much mass. >>>> >>>> Sure. Most of the mass of the atmosphere - about 90% - is below the >>>> tropopause. But the stratosphere stretches out quite a long way. >>>> >>>>> Â Â Â Â Frankly, if the lower troposphere doesn't provide >>>>> most of any GHG effect, then how can the lower pressure, colder, less >>>>> dense with less mass layers above have as much of an effect? >>>> >>>> This is correct - the air temperature declines as you go up through the >>>> troposphere whch is to say that you've got a temperature gradient >>>> through an insulating blanket, and stabilises once you hit the bottom >>>> of the stratosphere at the tropopause, which is to say that the >>>> stratosphere isn't functioning as an insulator. >>>> >>>> Note that the top of the troposphere is also pretty cold and thus >>>> nearly as low on water vapour. >>>> >>>>> Â Â Â Â Rather than try to put physics to such vague gossip >>>>> as spectra bands, it would be better to start from scratch, study the >>>>> temperature, pressure, mass, specific heat and energy content of a >>>>> quantity of the atmosphere at each level, and the capability to >>>>> radiate or absorb Infra- red. >>>> >>>> That's what the climatologists models do, but they also have to keep >>>> track of heat flux carried by mass-transfer - both by simple convection >>>> and the heat that is moved upwards as water vapour to be released when >>>> the water vapour condenses to liquid water (rain and clouds) and ice >>>> (ice clouds and hail). >>>> >>>>> Â Â Â Â CO2 plays such a small part in atmospheric physics, >>>>> it could be totally ignored without changing the outcome a measurable >>>>> amount. >>>> >>>> Wrong. >>>> >>>>> Â Â Â Â Water vapor concentration can increase and decrease >>>>> many times the total concentration of CO2 and it doesn't change the >>>>> temperature much, in fact, dry air can get hotter faster or colder >>>>> faster, than moist air. >>>> >>>> So what? >>>> >>>>> Â Â Â Â More moisture means more IR absorption, but moist >>>>> air moderates temperature changes. Â Â CO2 has no phase change at >>>>> atmospheric temperature and pressure, and has a very low activity >>>>> level compared to water and water vapor and ice. >>>> >>>> But is is very effective in "pressure broadening" the water vapour >>>> rotational lines - much more so than oxygen and nitrogen, which are >>>> non-polar molecules and don't stick to water during collisons for >>>> nearly as long as CO2. >>>> >>>>> Â Â Â Â At the temperatures at higher altitudes, IR >>>>> radiation is sparse, >>>> >>>> Nonsense, the Earth - or rather the tropopause - is a black body >>>> radiator in the near infra-red and the radiation flux out to the rest >>>> of the universe only depends on the temperature through the tropopause. >>> >>>Maybe we're getting somewhere now. How do you account for the fact the >>>tropospheric lapse rate stays close to adiabatic? >> >> Average lapse rate in the troposphere is close to the "wet adiabatic" >> figure while half the tropopause lacks clouds at any altitude. > >Do you think that the "wet adiabatic" environmental lapse rate is related >to latent heat, or is it simply less than the dry adiabatic lapse rate >because it's not at equilibrium? It is less due to latent heat. The "1 size fits all figures" that I have heard are 3.5 degrees F per 1,000 feet for the wet one and 5.4 degrees F per 1,000 feet for the dry one. >>> Is it primarily by radiative transfer, or convection? It seems to me >>>it must be convective, simply because warm, wet air is less dense than >>>cold, dry air, and quickly rises to maintain the lapse rate. >> >> Much of the time the answer is a significant factor other than >> radiation and vertical convection. Much of the "global convection" >> involves air movement within a degree of horizontal, and often forming >> clouds when moving upwards. Sometimes the lapse rate there is between >> the "dry adiabatic" and the "wet adiabatic" rates and the clouds have >> billowy cumuliform tops or are cumuliform throughout. Sometimes "warm >> advection" occurs more at cloud-top level than at cloud-base level (from >> the windspeed being greater higher up in the troposphere), causing the >> clouds to be stratiform. > >OK, that all sounds plausible, but I'm not sure how much effect the >horizontal component would have, other than the obvious mixing. The horizontal component involves atmospheric heat transfer from the tropics to the poles. It is very significant. It leads to frontal inversions, which cover significant area ahead of warm fronts (including areas where the warm fronts fail to reach at the surface). It leads to existence of stratosphere at middle and upper latitudes at pressure levels below that of the tropical tropopause. >>>IR radiated from the surface would be quickly absorbed by WV, clouds, >>>CO2, and other GHGs, and at 500W/m^2 would be overwhelmed by the 10's of >>>kW/m^2 available from convection of latent heat. >> >> Half the Earth's surface has no clouds overhead at any altitude. > >Surely you mean "at any given time". Or are there really regions >comprising half the Earth's surface that have never had a cloud in the sky? I did mean "at any given time", and "those given times" in "those given locations" account for half the world lacking clouds at any altitude. >> The surface manages to radiate *somewhat* to outer space at night when >> the air overhead is clear - otherwise there would be no such thing as >> nighttime frost when air 2 meters above the surface is at +2 degrees C >> (a fairly common situation). Some of the outgoing radiation can easily >> be absorbed and reradiated a couple or a few times by GHGs, but net of >> that is upward (and upward net is reduced by increase of GHGs). > >OK, no argument with that. I look at it as the surface radiating to a >target warmer than 3K space, but it's the same math. >> >>>At night, convection stops, but cooling is not required at night. >>>Convection kicks in during the day, when cooling is needed. >> >> Cooling still occurs at night by radiation. 5 AM temperature has a >> great rate of being less than 10 PM temperature. Upper level of >> radiation by atmosphere at night has half of its radiation to outer >> space. That heat comes from radiation from surface - even if absorbed >> and reradiated a couple times along the way. > >Agreed. At night the flux is always outward. > >> The "upper radiation level" also varies greatly with wavelength. > >Do you mean the "effective radiating altitude", which is calculated, or >some sort of integrated spectrum involving all the photons reaching a >surface outside the atmosphere, like a satellite imager? Neither I, nor >apparently Google, is familiar withe the term "upper radiation level". Looks like I did not choose wrds well - it should have been "effective radiating altitude". Keep in mind that the "effective radiating altitude" is very fuzzy, since some wavelengths radiated by the surface have good atmospheric transparency (and a fairly clear shot to space) as long as there are no clouds, others have low chance of reaching the 500 mb level without being absorbed, and some are in-between - with absorption and reradiation varying directly with concentration of GHGs. >>>I don't see how radiative cooling is even necessary below the cloud >>>tops, since there's plenty of cooling capacity from convection. >> >> When frost or dew forms on the ground and on cars and trucks, the heat >> loss has a very impressive rate of by being by radiation. > >True, but radiation is peanuts compared to the available cooling capacity >of latent heat during the day. If the surface radiation were blocked, >convection could easily make it up. What about on days when there is no convection past the 750 mb or so level for even a minute? (I see plenty of those even with sky half-clear and cumulus clouds present.) What about in Arctic and upper-midlatitude areas where change in radiation balance during the 18 or whatever hours per day with little convection has a significicant effect on snow/ice cover, and that affects how much solar radiation the surface absorbs? >>>Once the energy reaches the tropopause, as you imply, it's a pretty >>>straight shot to 3K deep space, since there's not much atmosphere left >>>to absorb IR. >>> >>>Perhaps it's easier to see if you look at the lapse rate as bounded at >>>the top by the effective radiating temperature, and consider the surface >>>temperatures as derived from that and the adiabatic lapse rate. >> >> That gets complicated by half the troposphere having lack of clouds at >> any altitude, and there are separate adiabatic lapse rates for clear air >> and clouded air. The global atmospheric average is close to the "wet" >> one, leaving upward mobility of lapse rate in the clear half of the >> world and in clear layers of the atmosphere in the clouded half of the >> world. > >At any given point, the applicable lapse rate should be obvious, depending >on whether cloud is present. I'm not convinced the lower "average" >environmental lapse rate has much to do with latent heat. It might just >be off-equilibrium due to transport lags or the like. It just happens to be that the "average lapse rate below the tropopause" is close to the wet adiabatic one. Close to the equator, it is more than coincidental - global circulation (from atmosphere below_tropical_tropopause_pressure_level as-a-hole) being warmer towards the equator and cooler towards the poles has air in the intertropical convergence zone rising. That largely establishes the lapse rate in the ITCZ as being close to the wet adiabatic one from the levels of the bases of the deep tall tropical convective clouds to the tropical tropopauuse. Below that cloud base level where those clouds form, the lapse rate is close to the dry adiabatic one at hot times of the day, and less at other times. Although it sounds like global circulation merely forces upward air movement in the ITCZ and that should cause clouds other than the billowy cumulus of natural convection, those show up anyway (along with a lot of clear air). Surface temperature in the ITCZ is not uniform. For one thing, some parts of the ITCZ have daylight and others have night. Also, ocean currents cool the ITCZ unevenly. So, upward air movement in the ITCZ occurs in hotspots where natural convection is sufficient to account for the upward global atmospheric circulation in the ITCZ - and the clouds there are billowy thunderheads, with many having anvil tops. Do keep in mind that there is global atmospheric circulation at altitudes and pressure levels that are troposphere in the tropics and stratosphere elsewhere. Air rising through the ITCZ to close to the 100 mb level does not all go down there but some descends elsewhere poleward. And a lot of that moves poleward at altitudes where the is little hope of convection to such level from the surface, due to surface being cooler than in the ITCZ. At some of these extratropical-stratospheric altitudes and pressure levels, atmosphere is even usually warmer than it is over the ITCZ because over the ITCZ it is so cold (from cooling by uplifting) that local radiation balance warms the air moving largely horizontally at/near the tropical tropopause level. It cools by radiation in order to descend elsewhere, with much of that done during the descent - especially in the polar regions. >Thanks for your clarifications. I appreciate rational discussion. > >> <I snip from that next triple-quote symbol due to lesser relevance to >> argument in this little region of the massive thread> >> >> - Don Klipstein (don(a)misty.com) - Don Klipstein (don(a)misty.com)
From: Bill Ward on 15 Dec 2008 00:10
On Mon, 15 Dec 2008 01:11:16 +0000, Don Klipstein wrote: > In article <pan.2008.12.07.07.55.55.626493(a)REMOVETHISix.netcom.com>, Bill > Ward wrote: > >>On Sun, 07 Dec 2008 05:45:26 +0000, Don Klipstein wrote: >> >>> In article <pan.2008.11.29.05.49.04.133668(a)REMOVETHISix.netcom.com>, >>> Bill Ward wrote: >>>>On Fri, 28 Nov 2008 19:35:59 -0800, bill.sloman wrote: >>>> >>>>> On 28 nov, 14:20, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> >>>>> wrote: >>>>>> z wrote: >>>>>> > and the fact that water vapor partial pressure rises with >>>>>> > temperature, thereby making it an amplifier of other effects, such >>>>>> > as CO2. >>>>>> >>>>>> An unproven hypothesis. i.e random noise. >>>>> >>>>> There's nothing unproven about the "hypothesis" that the partial >>>>> pressure of water vapour in contact with liquid water rises with >>>>> temperature. It's up there with Newton's law of gravity as one of the >>>>> fundamental theories of science. >>>>> >>>>> And more water vapour does mean more pressure broadening in the >>>>> carbon dioxide absorbtion spectrum. >>>>> >>>>> Carbonic acid (H2CO3) may not be stable in the vapour phase at room >>>>> temperature, but it is stable enough that any collision between a >>>>> water molecule and a carbon dioxide molecule lasts qute a bit longer >>>>> than you'd calculate from a billiard-ball model. >>>>> >>>>> Eeyore's response isn't random noise either, though it's information >>>>> content isn't any more useful - we already knew that Eeyore knows >>>>> squat about physics, and he's long since made it clear than he >>>>> doesn't realise how little he knows by posting loads of these >>>>> over-confident and thoroughly absurd assertions. >>>> >>>>He may also be aware that increased water vapor lowers the condensation >>>>altitude, >>> >>> Cloud bases lower if relative humidity rises. Relative humidity >>> stays >>> about the same if water vapor concentration is only commensurate with >>> temperature rise. >> >>Interesting concept. I'm assuming the surface temperature determines the >>absolute humidity, and the condensation altitude would be determined by >>the lapse rate downward from the cloud tops (radiation layer). It seems >>to me the surface temperature varies a lot more than the higher >>altitudes. > > It sure does! In fact, at the pressure level of most of the tropical > tropopause (around or a little over 100 mb), on average it is cooler over > the equator than over the poles! > >>Is there any actual data on the altitude of the radiation layer that >>radiates the most power? From what I've seen, it's mid troposphere, not >>the tropopause. Are there any credible models of the individual >>mechanisms from cloud tops to the tropopause? > > That I know much less about. However, over the range of wavelengths at > which the surface produces a lot of thermal IR, the transparency of the > atmosphere varies greatly. My thought is that it wouldn't take much of an increase of temperature by lowering cloud tops (assuming the same cloud thickness) below relatively dry air, to radiate quite a bit more power through the tropopause. It seems to me this information should be available from satellite images, but I haven't seen it mentioned. >>>> raising the radiation temperature, and increasing the emitted IR >>>>energy by the 4th power radiation law. IOW, it's a negative feedback, >>>>not positive. >>> >>> Radiation from cloud bases is toward Earth. >> >>I think that concept confuses people, at least me, when I first heard >>it. >> It appears at first glance you are claiming the cloud bases are warming >>the surface, which is clearly impossible by the second law. The clouds >>are colder than the surface, and energy can never radiate from cold to >>hot. > > Cloud bases slow cooling of the surface in the usual case of cloud > bases > being cooler than the surface. There is radiation from surface to cloud > base and radiation from cloud base to surface. The latter is less in > the usual case of cloud base being cooler than surface, but that does > subtract from net radiation from the surface. There's an example of a confusing statement. To me, the net surface radiation is the outgoing surface radiation minus the incoming radiation from the cloud base. Subtracting the cloud base radiation from the net radiation seems to me like double counting it, or an unusual use of the word "net". Was that a typo, or is it something you can explain? >>A little more thought reveals the actual mechanism must be that some of >>the radiation that comes from the surface can be considered to be >>radiated back to maintain the (Tsource^4 - Ttarget^4) term in the >>Stefan-Boltzmann equation. That still requires that the net heat flow >>is outward, never inward (unless the surface is cooler). The upper >>layers may reduce the cooling rate of the surface, but they can never >>actually heat it. >> >>The _net_ radiation has to be from the surface to the clouds. > > It is. And since clouds emit some radiation towards the surface, and > emit more radiation towards the surface than clear air does, they slow > radiational cooling of the surface. Right. It slows the cooling, but the surface never increases its temperature by radiation from a colder source. >>> Meanwhile, increasing GHGs cools the lower stratosphere and raises >>> the >>> tropopause - cloud tops around the tropopause will be cooler. >> >>I'm not clear why. Could you explain why a cooler stratosphere raises >>the tropopause? Is it because the tropopause is the top of convection, >>so a colder stratosphere allows convection to continue higher before the >>UV-O2, O3 inversion takes over? >> >>Thanks for your comments. > > The tropopause is generally the top of convection - although there is > not convection under it everywhere. If the stratosphere is cooler, then > the convection can go higher. > > The tropopause is highest in the tropics. Global circulation has air > over the equator generally moving upward, since tropospheric temperature > overall is warmest there. Wouldn't the tropical air moving upward be humid, and carrying a lot of latent heat? > Where the upward motion actually exists and it does get localized to > the hotspots where air rises most easily, the lapse rate makes a close > approximation of the dry adiabatic one from the surface to the cloud > base, and the wet adiabatic one from the cloud base to the cloud tops at > the tropical tropopause. > The tropical deep convection is in part forced by global circulation, > and in part (especially on a local scale) natural convection from where > the surface is warmer than elsewhere nearby. On a local scale, there is > both updraft and downdraft, though in the intertropical convergence zone > net air motion is upward. If warm wet air is going up, and cold, dry air is going down, the "net" air motion would seem to be somewhat irrelevant, compared to the latent heat transfer represented by up- and down-drafts in the convection cells. Do you think climate models simulate that correctly? I'm thinking of Trenberth's assumption that latent heat transfer can be accurately estimated by from global precipitation estimates. How do we know some of the falling condensate isn't evaporated again before it hits the surface? It wouldn't take much to counter 1.5W/m^2. > The air rises until it cools so much that it > can't rise anymore, and some will descend locally and some will move > poleward and descend somewhere outside the ITCZ. > > - Don Klipstein (don(a)misty.com) |