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From: Don Klipstein on 21 Dec 2008 21:30 In article <8tmjk4l3ve92pj053pkv2jb5fmueh7eofh(a)4ax.com>, Whata Fool wrote: >don(a)manx.misty.com (Don Klipstein) wrote: > >>In article <4juoj4lpnt8pmml6srpt2a9vtt2clnmc99(a)4ax.com>, Whata Fool wrote: >>>Eeyore <rabbitsfriendsandrelations(a)hotmail.com> wrote: >>> >>>>Martin Brown wrote: >>>> >>>>> Eeyore 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. >>>>> >>>>> You are clueless. That warmer air can carry more water vapour is a well >>>>> known experimental fact. >>>> >>>>You fail to address the idea it's an *amplifier*. >>>> >>>>Graham >>> >>> >>> Because it is obvious that more water vapor is a temperature moderator, >>>and a very beneficial and effective one. >> >> Well, when we have more GHGs, the areas that warm the most tend to be >>cooler ones in/near the Arctic and Antarctic (especially the Arctic). > > > And you are sure it is GHGs causing it? There has to be more >to it than that to account for the ice ages and sudden warmings. The ice ages apparently come and go in response to slight periodic changes in insolation at a critical latitude range in the Northern Hemisphere. Necessary is a lot of positive feedback. That is apparently from changes in water vapor concentration, changes in CO2 concentration (colder water holds CO2 more easily), and changes in snow and ice cover. >> With more water vapor, dry hot areas can fail to have their hottest >>times of day getting hotter - they would produce thunderstorms more >>easily. That may explain a climate change forecast model I saw many >>years ago predicting that Arizona would not get much hotter as the >>globe is warmed by increase of GHGs. But their nights will be warmer. > > So the whole ball of wax is about whether the cooling of the days >is less than the warming of the nights? Areas that get more humid will have cooler days and warmer nights. > Didn't you say that up a mile the temperature is just as cold >over desert? Yes, I do somewhat remember saying that at 1 mile up, air temperature is generally not warmer over desert than over more humid areas. >>> All CO2 can do is absorb and emit, which can only cool the huge mass >>>of the atmosphere, >> >> And warm it when it absorbs more than it emits, which it sometimes does. >>And slow cooling of the surface, since some of the radiation it emits is >>downward. > > It can't absorb much more than it emits without transferring >any excess to the N2 and O2. > > When half is downward and half upward, with less coming down >from above because of the lower temperature and lower density, that >is a net loss. GHGs are receiving radiation also from below. GHGs at lower altitudes have GHGs at higher altitudes overhead shining some of their radiation onto them. > Without GHGs, all heat the N2 and O2 absorbs from convection >is retained, which means the Earth would be warmer without GHGs. Except that GHGs warm the surface, which warms the lower atmosphere. > Please don't confuse that with "no atmosphere". I was comparing to GHG-free atmosphere, not no atmosphere at all. >>> CO2 doesn't have enough mass to store or hold any thermal energy. >>> >>> The N2 and O2 get warmed by the various processes, solar radiation, >>>contact and convection, and radiation via water vapor and the trace GHGs, >>>and the N2 and O2 hold that thermal energy until the GHGs radiate it to >>>space. >>> >>> In order to see what this means, the temperature of an N2 and O2 >>>atmosphere and NO GHGS has to be estimated, and compared to the present >>>temperature, and that tells the net result of the GHG effect. >> >> For one thing, the world's surface temperature is warmer than it would >>be than that of a blackbody in Earth's orbit, despite ratio of low >>temperature emissivity to solar radiation absorption exceeding 1. There >>is some sort of impedance to outgoing radiation from the surface. > > Again, the question of whether or not more GHGs warm or cool >more hinges on whether or not the N2 and O2 atmosphere would be warmer >than now, and the answer is obviously that it would be warmer, because >there would be no AIR - SPACE cooling mechanism! The portion above the tropopause would be warmer. And the tropopause would be much lower. The surface and surface-level atmosphere would be cooler. >>> It has to be that GHGs cool the N2 and O2, which is 98 percent of >>>the mass of the atmosphere, so more GHGs should cool the atmosphere a >>>little more. >> >> The atmosphere above roughly the 350 mb level (about 8 km) would indeed >>cool, except for surface warming increasing reception of sunlight. > > Your sentence seems to relate to two different things, Yes it does - sorry. If surface albedo stays the same, then increasing GHGs will cool the portion of the atmosphere above the 350 mb level. (Until the increase is so great that there are enough GHGs above the 350 mb level to warm that level.) The exception is if surface temperature increase causes the Earth to absorb more sunlight. > but if more CO2 would cool the upper third more, how can it warm the >lower two-thirds more, isn't there a pretty standard lapse with >altitude? Not really. Most of the troposphere has lapse rate less than the adiabatic lapse rate. >>> The actual solid and liquid surface temperatures vary so much as >>>a result of many factors, the "surface" temperature doesn't matter much >>>during an interglacial period. >> >> - Don Klipstein (don(a)misty.com) > > If CO2 and GHGs were all that big a factor, the local temperature >should be more constant, and the weather fronts should be less of a >factor. > There are often warm clear nights, and cool clear nights. How >can there be so much variation with a slowly changing CO2 concentration? 1. If the air recently moved in from someplace else warmer or cooler. 2. Water vapor is a GHG, and concentration of it in any given location varies greatly. > The effect of CO2 seems greatly over rated, and more should cool >more instead of warm. - Don Klipstein (don(a)misty.com)
From: Bill Ward on 21 Dec 2008 23:28 On Sun, 21 Dec 2008 02:16:01 +0000, Don Klipstein wrote: > In <pan.2008.12.08.09.55.26.820279(a)REMOVETHISix.netcom.com>, B. Ward said: >>On Mon, 08 Dec 2008 05:06:34 +0000, Don Klipstein wrote: >> >>>In <pan.2008.11.30.20.54.34.361748(a)REMOVETHISix.netcom.com>, B.W. said: >>>>On Sun, 30 Nov 2008 07:13:33 -0800, bill.sloman wrote: >>>> >>>>> On 29 nov, 06:43, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>> On Fri, 28 Nov 2008 19:25:22 -0800, bill.sloman wrote: >>>>>> > On 27 nov, 20:50, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>> >> On Thu, 27 Nov 2008 07:50:47 -0800, bill.sloman wrote: >>>>>> >> > On 27 nov, 06:32, Bill Ward <bw...(a)REMOVETHISix.netcom.com> >>>>>> >> > wrote: >>>>>> >> >> On Wed, 26 Nov 2008 17:09:40 -0800, bill.sloman wrote: >>>>>> >> >> > On 26 nov, 22:17, Bill Ward <bw...(a)REMOVETHISix.netcom.com> >>>>>> >> >> > 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> >>>>>> >> >> >> >> ÃÂ wrote: >>>>>> >>>>>> >> >> >> >> >bill.slo...(a)ieee.org wrote:> >>>>> >>>>> <big snip - Bill Ward does go in for mindless repetition> >>>>> >>>>>> > Since the effective radiating altitude is 6km above ground, right >>>>>> > in the middle of the troposphere, this seems to be exactly the >>>>>> > right place for a radiative transfer model to be effective. >>>>>> >>>>>> There's an excess of water vapor available to convect latent heat up >>>>>> to the effective radiating altitude. >>>>> >>>>> The air at the effective radiating altitude is well below the >>>>> freezing point of water - the earth radiates as if it is a black body >>>>> at -14C, and while this is an average over all wavelengths (for >>>>> wavelengths absorbed and re-radiated by CO2 the temperature has to be >>>>> closer to -55C) it makes sense that the radiation appears to come >>>>> from a layer where water vapour - the predominant greenhouse gas - >>>>> has condensed out. >>>>> >>>>> The partial pressure of water vapour above the cloud tops is too low >>>>> to convect any signficant latent heat higher >>>> >>>>You seem to be going to great lengths to repeat my points as though >>>>they were your own. I'll take that as a compliment. Once the cloud >>>>has condensed, its latent heat has radiated from the cloud tops, >>> >>> Radiation of the heat (latent or otherwise) does not occur the >>> instantly. The air may descend somewhere else before losing all its >>> heat to radiation. >> >>True enough. I misspoke. I should have said the cloud starts radiating >>as soon as it begins forming, and continues from that point on. > > That is true. At this moment what I am in the best mood to add here is > that cloud tops near tropopause do not account for most longwave IR > radiation from this planet to "outer space". > > There is even convective cloud formation building to altitudes where > cloud tops have low ability to cool by radiation - mostly within ITCZ > (intertropical convergence zone), where the updrafts, much of which are > part of "global atmospheric circulation" while also "largely confined to > ITCZ convection ghotspots", rise to levels so high that their cloud tops > are so cold as to either have overshot or else have achieved temperature > so low as to experience *warming* by "local radiation balance", including > influence of the "upper stratosphere" and the "thermosphere". > > How things appear to me - the tall/deep convective clouds in/near the > ITCZ "largely-establish" the lapse rate from a few or several hundred > meters above surface to "ITCZ tropopause level" (lower altitudes have a > high rate of achieving lapse rate well short of convection within that > latitude-zone during the 18-20 or so hours of each day when within-ITCZ > something like 95-97% lacks such tall deep convection). > >>>> and has a clear shot to space. Above the cloud tops, WV is gone, > > A few articles ago I did mention 2 points: > > 1: How radiation-clearshots-to-space or fails to do so varies with > wavelength through noted bands. > > I do consider noted that major GHG abosorption bands with significant > ability to both absorb and radiate at "relevant temperatures" has their > relevant spectral features of Earth's atmosphere changing by only a small > amount if such GHGs have their "atmospheric concentartion" so much as > halved or doubled. > > But keep in mind that over the past few hundred thousand years we have a > record of great global temperature fluctuation (10-12 K or so) in response > to "Milankovitch Cycles" affecting reception of hugely-much-smaller > changes of solar radiation at Arctic and near-Arctic latitudes > most-noted-as-around 65 degrees N. > >>>>radiation is effective, convection isn't needed. >>> >>> What about when CO2 is present? What about when cloud tops are low? >> >>There's not much CO2, and when cloud tops are low, temperature is higher >>and radiation is greater. > > When cloud tops are lower, lapse rate is lower. Low cloud tops are > mostly where the troposphere has convection limited to a low range of > altitude from, the surface (a bit common), otherwise when cloud tops are > both low and stratiform. (Cloud tops can easily be a few km below the > tropopause.) > > And the radiation from cloud tops that low mostly runs into GHGs. > >> It's the integration over the area of >>the Earth that counts. A few very effective radiating spots could make a >>big difference. > > Keep in kind that much of that is from: > > * GHGs in clear air (70% of which exist above the 700 mb level) * Cloud > tops so low as to have most GHGs above them, even including water > vapor - almost halof of which exists above the 700 mb level > >>>>>>ÃÂ It's in the 10s of kW/m^2 compared to the 500W/m^2 max from >>>>>>surface radiation. ÃÂ >>>>> >>>>> It was at the surface, where the partial pressure of water vapour is >>>>> around 2300 Pa. The saturation vapour pressure has dropped to 603 Pa >>>>> by the time the temperature has dropped to zero Celcius. It drops off >>>>> even faster over ice, so it certainly isn't beating radiation at the >>>>> effective emitting altitude. >>>> >>>>Assume at the surface boundary layer we have a thermal with a given >>>>humidity and velocity. What do you think happens to a parcel of air, >>>>and the energy it contains, as it rises? Keep in mind that matter and >>>>energy are conserved. >>>> >>>>I can tell you, from direct observation, that it continues upward at a >>>>relatively constant velocity until it reaches either a change in the >>>>lapse rate, or the condensation altitude (cloud base). You need to >>>>rethink your position to include that easily verifiable fact. You also >>>>need to get out more. Try riding a sailplane in a thermal. >>> >>> Not that most of the world has thermals from surface to tropopause - >>> those are thunderstorms. >>> >>>>> http://www.engineeringtoolbox.com/water-vapor-saturation-pressure-air-d_689.html >>>>> >>>>> http://www.answers.com/topic/dewpoint-jpg-1 >>>>> >>>>> http://faculty.matcmadison.edu/slindstrom/VaporPressure.doc >>>> >>>>Thanks for the supporting links. I may have posted a couple of them >>>>before. >>>> >>>>>>The lower troposphere is translucent in the 15u band. ÃÂ How >>>>>>could CO2 play any significant part, compared to radiation? Above the >>>>>>clouds, it has a clear shot to >>>>>> space. >>>>> >>>>> CO2 has both 5u and 15u absorbtion bands >>> >>> I would like to add that the 15 um band is significant at surface >>> level temperatures. At 288 K, a blackbody has spectral power >>> distribution about 71-72% of peak. >> >>Sorry, I don't understand what that means. Can you explain? > > At the 288K temperature that for 1950-1980 or 1930-1980-average that is > of Earth''s surface (or atmosphere 4 feet or 2 meters above), thermal > radiation at 15 um per-unit-area per-wavelength-unit-bandwidth is 71-72% > of the peak for such temperature. > >>>>Please. Are you now claiming that the surface is radiating >>>>significantly in the 5u band? You're the radiation expert, what BB >>>>temperature would that represent? My BOE guess is about 300C, which >>>>seems a bit unrealistic for Earth, >>> >>> At 288 K, a blackbody has spectral power distribution about 22% of >>> peak at 5 um. There is some surface radiation in that band being >>> absorbed by CO2 overhead. >> >>What percent? It's a fairly narrow band, overlapping water. > > I would like to say: > > http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png > >>Can you explain, using this graph? It looks like less than 5% of the >>area under the spectrum to me. >> >>http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png > > That is a wavelength range at which CO2 is much more significant than > water vapor despite greater existence of WV than CO2 in this plantet's > atmosphere. Also, even in this band (as opposed to the > 15-uM-centetred-one) CO2 is a significant greenhouse gas, and at > wavelength ranges within this band change of concentration of CO2 changes > number of absorptions/re-emissions of thermal radiation at wavelengths in > or towards the edges of this band. > Though I consider the 15-uM-centered one more significant than the > near-5-um-centered one for now. Yeah, judging by the graph, there doesn't seem to be much IR going either way at 5u. >>>> especially at the effective radiation altitude. Looks like you've >>>>reached the bottom of the barrel. >>>> >>>>> http://www.wag.caltech.edu/home/jang/genchem/infrared.htm >>>>> >>>>> What do you mean by "translucent"? >>>> >>>>Scattering rather than absorbing, like the frosted glass on a light >>>>bulb. I was humoring you. I suspect the lower troposphere is nearly >>>>opaque to the 15u band, and satellites are just seeing emission from >>>>the top layer. It doesn't matter either way to the argument. > > Keep in mind that "foggy translucent" by absorbing and re-emitting > thermal radiation with all relevent temperatures nearby means that > adding GHGs effectively adds a "distrubted layer" (or fraction thereof) > of absorption/re-reradiation of longwave IR. That does cause surface to > need to have its temperature increase in order to lose heat > radiationally to outer space as it did before. That's why I believe the convection component is important. It's in parallel, and independently adds to the radiative component. > (Keep in mind my previous response along the "pinball argument" (my > words). > > >>>>> CO2 absorbs and retransmits infra-red radiation at specific lines >>>>> within both bands, and this radiation won't have a "clear shot at >>>>> space" until it gets high in the stratosphere. >>>> >>>>How much? And how much difference does it make in view of the negative >>>>feedbacks involved in the convective transfer? Try considering the >>>>lower troposphere as a variable (temperature sensitive) thermal >>>>resistance > > Thermal resistance has a negative temperature coefficient for convection > and a positive one for radiation (due to water vapor increasing with > temperature, and secondarily due to percentage of CO2 dissolved in oceans > decreasing as sea-level temperature increases). > > Keep in mind that so little of the world is covered by "deep > convection", > and close to half lacks clouds at any altitude, that radiation other than > from clouds at any altitude (let alone restriction to cloud tops within > even 4 km of tropopause) is currently a minority of this planet's > "radiation outgo" that balances its "radiation income" from the Sun. > >>> The majority of the troposphere that is lacking convection has >>> thermal >>> resistivity not collapsing until convection occurs. That portion of >>> the tropospher has upward mobility in lapse rate. >> >>Local convection should still be quite effective. > > Except that in most of the world it does not exist at any layer of the > atmosphere having cliuds - close to half the world lacks clouds at any > altitude. There is also significant cloud top over this world where the > cloud tops are stratiform, and in addition to that a fair amount of the > cumuliform (convective-turbulent) cloud tops being in the lower half of > the troposphere. It seems to me you are saying the sky is half empty, and I'm saying it's half full of clouds. Until some definitive, quantitative study can decisively show the actual overall feedback, it appears the question of deep convection as a possible negative feedback component must remain open. > >>>> and the region above the radiating layer as a relatively smaller, >>>>slightly CO2 sensitive resistance. >>>> >>>>> CO2 is also disproportionately effective at broadening water vapour >>>>> absorption lines, and this will be significant in the region close >>>>> above the cloud tops where there's still some partial pressure of >>>>> gaseous water to absorb and retransmit at water vapour's absorbtion >>>>> lines. >>>> >>>>OK. Now use your radiative transfer model to compare that to the >>>>effect of warming (lowering) the emitting layer a few degrees. Don't >>>>forget the T^4 term. >>> >>> Lowering of the emitting layer is what happens if GHGs are reduced. >> >>Why would GHGs necessarily be involved, since clouds radiate as black >>bodies? > > For one thing, so far a lot of radiation from this planet to outer > space > to throw back out what it received from the Sun is not from clouds, but > from clear air or from the surface. > At current atmospheric concentrations of GHGs, there remains > wavelengths at which emission at relevant tremperatures is significant > and at which the entire atmosphere still has or recently had significant > transparency. > >>> Except the emitting layer will still have the temperature appropriate >>> for 1/4 of the solar constant times ratio of solar absorption to >>> emissivity of the radiating layer. >> >>Not if the surface temperature has increased. The lapse rate won't >>allow it. The temperature of the emitting layer will increase, >>radiating the heat necessary to cool the surface back down - negative >>feedback. > > Except that most of the world has room to warm significantly before > vertical convection sets in. > Especially regions where surface albedo to incoming solar radiation is > subject to change as a result of change in radiation balance > (specifically change in temperature necessary to maintain such) - > Much of the world having snow/ice cover reduced by increase of GHGs > can > easily warm quite a bit with awfully little increase of local convection > from surface or lowest km to so much as 4 km above sea level. > And warming of areas so close to the poles will if anything reduce > "net global convection" via "global atmospheric circulation" by means of > "advection" (which is heat transfer by fluid flow that is, for planets, > largely horizontal). I agree that not all the world is primarily cooled by convection. The open question is whether negative feedback from convection, etc, is enough to offset the GHG effects of CO2. Climate model estimates are not very convincing to me. > >>>>Sorry about the repetition, but it was worth it, since you have now >>>>apparently caught on to what I was saying. I'm more pragmatic than >>>>polite, I guess. > > Not that I always fail to be rude; I merely do that most of the time > and > also I "let facts get in the way" most of the time! > >>> - Don Klipstein (don(a)misty.com) > > - Don Klipstein (con(a)misty.com)
From: Bill Ward on 21 Dec 2008 23:41 On Sun, 21 Dec 2008 03:01:11 +0000, Don Klipstein wrote: > In article <pan.2008.12.08.08.36.56.199364(a)REMOVETHISix.netcom.com>, Bill > Ward wrote: >>On Mon, 08 Dec 2008 03:54:11 +0000, Don Klipstein wrote: > > Oh so long ago, boy-oh-boy am I so slowed down this time of this year, > majority of 2 weeks! > >>> In <pan.2008.11.29.05.43.32.198332(a)REMOVETHISix.netcom.com>, Bill Ward >>> wrote in part: >>> >>>>On Fri, 28 Nov 2008 19:25:22 -0800, bill.sloman wrote: >>>> >>>>> On 27 nov, 20:50, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>> On Thu, 27 Nov 2008 07:50:47 -0800, bill.sloman wrote: >>>>>> > On 27 nov, 06:32, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>>>> >>>>>> > <snip> >>>>>> >>>>>> >> As you put it up thread, "the stratosphere isn't functioning as >>>>>> >> an insulator." >>>>>> >>>>>> >> If the stratosphere is transparent, and there is an excess of >>>>>> >> convective capacity in the troposphere (driven by the lapse >>>>>> >> rate), how can trace amounts of CO2 affect surface temperatures? >>>>>> >> If convection is sufficient to get latent heat to the tropopause, >>>>>> >> where it can radiate from cloud tops, etc, it has a clear shot at >>>>>> >> 3K deep space. The tropopause is there because it represents the >>>>>> >> top of the convective mixing layer. Because of increasing UV >>>>>> >> heating, the stratosphere has an inverted lapse rate, which >>>>>> >> prevents convection. >>>>>> >>>>>> > You seem to have set up a straw man by claiming that you can slice >>>>>> > the atmosphere into three layers - >>>>>> >>>>>> > - the troposphere where heat transfer is only by convection >>>>>> >>>>>> > - a very thin tropopause which does all the radiation >>>>>> >>>>>> > - the stratosphere which does nothing >>>>>> >>>>>> > which - unsurprisingly - leads you to incorrectly conclude that >>>>>> > CO2 cann't do anything. >>>>>> >>>>>> Where did I say the radiation all comes from a thin layer? You must >>>>>> be misinterpreting the concept of effective radiating altitude. >>>>> >>>>> I very much doubt it. The proposition that the you think that all the >>>>> radiation comes from a thin layar at the tropopause folows direcly >>>>> from your claim that radiation doesn't play a significant role >>>>> anywhere in the troposphere, which strikes me as implausible. >>>> >>>>Below the effective radiating layer (cloud tops) radiation is swamped >>>>by convection, so CO2 can have little effect. >>> >>> What about in the majority of the troposphere lacking convection? >>> And >>> how are cloud tops the effective radiating layer in the half of the >>> world that lacks clouds? >> >>It doesn't have to be everywhere, just in the places where most of the >>cooling takes place, such as the tropics. > > For one thing, most radiative cooling of this world to balance > radiative warming from the Sun is mostly not from cloud tops anywhere near > trhe tropopause, I might dare say mostly from where this planet lacks > clouds at any altitude. > > The tall deep convective clouds in the ITCZ ("Inter-Tropical > Convergence Zone" rise so tall there with assistance by "global > atmospheruic circulation" - with suitably-weighted-average over relevant > altitudes of the atmosphere it is warmer in the tropics than towards the > polses, so in ITCZ the atmosphere generally rises and towards the polses > the atmosphere generally sinks. > We achieve a "heat engine" here - namely one of "global atmospheric > circulation" notably achieving the cold-spots-at-top-level-troposphere of > tropical air rising where it does on-average gets even-colder than most of > this planet's atmosphere elsewhere. > Such a model works due to most despite not all levels of the atmosphere > involved in "global circulation" being warmer towards the equator and > colder towards the poles. > > Air rising in "tropical deep convection hotspots" is assisted in its > rising to altitudes so high that it cools to temperatures so cold that on > worldwide annyual average, in the ITCZ is where air that high is so cold > (-60 to -75 C or whatever). > > Keep in mind that most of the tropics are clear and most cloud tops are > elsewhere in the world and both lower and warmer - despite "global > atmospheric circulation" having a very significant part through the small > minority of the tropics covered by tall deep thunderheads within/near the > ITCZ. > >>>> Above the radiating layer, there's not much CO2 left, > > Based on my latest calculations as to oversimplification as to what > that altitude is (350 mb level, roughly 7.6-8 km above sea level > give-or-take), 35% of all GHGs other than water vapor are above this > level. A smaller percentage of this planet's atmospheric WV is above this > level. > As for what "pressure level" is 50-50 - the "500 mb level" is close > enough for all GHGs other than WV, and the "700 mb level" is close enough > for WV - that one is noted as having great positive correlation between > "vertical velocity" and "precipitation production" ("my words"). > >>> Assuming Earth reflects half of solar radiation and has .95 >>> emissivity >>> of low temperature thermal IR (the figure on my non contact >>> thermometer), Earth radiation achieve radiation balance at 237-238 K. >>> (I may have posted a few degrees lower before by forgetting the .95 >>> figure). 237 K is about -36 C. >>> >>> 237 K is when 95% of blackbody radiation intensity is 1/8 of the >>> solar >>> constant. >>> >>> Average location of a photon radiated from Earth to outer space is >>> where >>> temp. is -36 C, but that is give-or-take a lot, since a lot of thermal >>> radiation can go some fair distance through the atmosphere before being >>> absorbed. >>> >>> On average, the altitude at which temperature is 237 K is around the >>> 300 >>> mb level, which has about 30% of the mass of the atmosphere above it. >>> However, a lot of photons radiated to space from Earth come from >>> greatly >>> different altitudes, some of which have more than 30% of the atmosphere >>> overhead. >>> >>>> and the 15u band is off peak, >>> >>> Peak wavelength of a blackbody at 237 K is around 12.5 um. At 15 um, >>> radiation is about 91% of that at peak wavelength. >> >>You are 18K lower than another similar analysis: >> >>http://www.atmos.washington.edu/2001Q1/211/notes_for_011001_lecture.html >> >><begin excerpt> > > I run low in time for this evening after this evening's load of beers, > but I do so far mention that your most-immediate-above cite mentions a > figure of 30% of solar radiation reflected, while I have been working on > 50%-reflected. > > The above link says solar constant is 1368 watts per square meter. (I > was working previously on 1366.) > > 70% of that times 1/4 is 239.4 watts per square meter, with blackbody > radiating that at indeed 255 K to nearest degree or even half a degree > probably. > So far for this evening, I would say that "standard atmosphere" of this > planet is 288 K at the surface and cooling at close to the > "1-size-fits-all-wet-adiabatic-lapse-rate" until hitting tropopause, which > at this rate would be 255 K or a bit over 5 km from surface or hardly at > all below 500 mb level. > > Keep in mind that albedo of our planet to solar radiation appears to me > to be currently closer to 50% than to 30%, due in part to slight > reflectivity of water surface, maybe due in slight part to reflectivity of > low clouds and land, and also appearing to me to be due to significant > (though also minority) reflectivity of snow and ice cover - some of which > goes away if the surface and/or lower troposphere is warmed by increase of > GHGs (or anything else). This is one of the areas that puzzle me. I've seen estimates of the CO2 "forcing" term from 0.5W/m^2 to 2.5W/m^2. You mention estimates of the Earths albedo from 30% to 50%. That would represent from about 72W/m^2 to 120W/m^2. The issue in question is the difference, if any, between the incoming SW and outgoing LW, each around 240W/m^2. How can the difference (CO2 forcing) be known so accurately, and the albedo be so uncertain?
From: Don Klipstein on 22 Dec 2008 07:39 In article <pan.2008.12.09.17.36.37.607052(a)REMOVETHISix.netcom.com>, Bill Ward wrote: (With snip of at least stuff already quoted more than 3 times) >On Tue, 09 Dec 2008 07:09:08 +0000, Don Klipstein wrote: > >> In <pan.2008.12.04.08.02.57.92862(a)REMOVETHISix.netcom.com>, B. Ward wrote: >>>On Thu, 04 Dec 2008 03:45:45 +0000, Don Klipstein wrote: >>>> But CO2 is close to blackbody within some range of wavelengths where >>>> emission is close to peak of a 218 K blackbody. And the range does >>>> widen somewhat when there is more CO2 in the atmosphere. >>> >>>Look at this graph: >>> >>>http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png >>> >>>Now please tell me if you think the CO2 absorption spectrum (3rd graph) >>>is similar to the 210K blackbody emission spectrum line in the top graph. >> >> I did not claim that - I merely claimed (using maybe better words now >> than before) that CO2 in the atmosphere radiates close as well as a >> blackbody does within the 15um-peaking band. >> >> The 210K spectrum does indeed have its peak close to CO2's 15 um band, >> so CO2's 15 um band will absorb and radiate some very significant amount >> at 210K. > >My guess from looking at the spectra would be less than half as much, >assuming the area under the spectrum is proportional to power. Yes, that band looks to me eyeball-estimate worth 20-25% of blackbody radiation at 210 K and less at higher temperatures. > And water shares the band. The atmosphere according to the above link has around 50% transparency of water vapor in that band, though I'm sure that varies widely since concentration of water vapor in the atmosphere is far from constant. In polar areas where surface temperature has more upward mobility, there is less water vapor and CO2 accounts for a higher percentage of GHG effect. Worldwide, CO2 accounts for 9-26% of GHG effect. I suspect the wide range is in large part due to water vapor concentration being very far from constant. Another factor is probably diversity of temperature shifting relative radiation abilities of different wavelength bands of different GHGs. >>>Assuming you agree they are different, please explain how CO2 bonds >>>could emit in wavelengths they can't absorb. <SNIP> >>>> CO2 acts fairly like a blackbody at wavelengths within the 15 um >>>> band. >>>> 15 um is a wavelength where a blackbody has spectral power >>>> distribution about 96% of peak. >>> >>>It appears to me both tails of a 210K blackbody spectrum are missing >>>(looks like about half the total area). Cold CO2 is not a black body - >>>it's a narrowband source. >> >> I was merely saying that CO2 is a significant absorber and radiator at >> 210 K. > >OK, that I will buy. - Don Klipstein (don(a)misty.com)
From: Don Klipstein on 22 Dec 2008 08:11
In article <vtibk4htk51b39oa7s2ll1rlnqinpusqc9(a)4ax.com>, Whata Fool wrote: >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? Not if the surface is cooler. Meanwhile, our current atmosphere has daily temperature change mostly within 1 mile of the surface. I have seen plenty of 850 mb charts, and temperature that low does not vary much throughout the day. Apparently, in our current atmosphere the coldest the 850 mb level gets is usually not much colder than a temperature that would be established by convection from the surface at the hottest time of the day. >>>>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? No, the troposphere would have a temperature profile with lapse rate at the dry adiabatic one, getting colder from day's high temperature as altitude increases. It would be much thinner than the one we have now, however. Surface temperature, unlike what we have now, would be determined by thermal radiation. If solar radiation absorption and thermal IR emissivity were equal percentages, then the blackbody radiation formula predicts a surface temperature (more specifically mean 4th root of mean of 4th-power of surface temperature), with 1366 watts per square meter of solar constant and Earth's cross section being 1/4 of its surface area, of 278.5 K. Average will be less than "root-mean-4th", and the current average surface temperature is about 10 K higher than that despite solar radiation absorption being less than IR emissivity. Keep in mind that with Rayleigh scattering by the atmosphere, the surface of a planet in Earth orbit with a cloudless atmosphere will receive less than 1/4 of 1366 watts per square meter. http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png makes it appear to me that eyeball-estimate 15% maybe 20% of solar radiation is either blocked by ozone and oxygen in and above the stratosphere or scattered away from the surface by Rayleigh scattering. 15% less would have "root-mean-4th" surface temperature on a GHG-free planet in Earth's orbit of about 267.5 K, if solar absorption and thermal IR emissivity were equal percentages. > (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? That and similarly high quality ocean buoys. >>>>> 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? Solar constant is 1366 watts per square meter. Earth's surface area is 4 times its cross section, so average insolation on a cloudless planet would be 341.5 watts per square meter, minus whatever is absorbed by ozone and oxygen in and above the stratosphere, minus whatever is scattered away by Rayleigh scattering. Assuming that this GHG-free "Earth" has ratio of thermal IR emissivity to solar absorption same as that of a blackbody, that works out to 279 K to the nearest degree. Specifically, that would be "root-mean-4th-power" surface temperature, and the average would actually be less. >> 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. - Don Klipstein (don(a)misty.com) |