The world has never seen such freezing heat
in [Design]
|
Prev: Class D audio driver with external mosfets
Next: NE162 mixer: input/output impedance in balanced mode?
From: Whata Fool on 18 Dec 2008 00:51 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. > 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? Didn't you say that up a mile the temperature is just as cold over desert? >> 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. Without GHGs, all heat the N2 and O2 absorbs from convection is retained, which means the Earth would be warmer without GHGs. Please don't confuse that with "no atmosphere". >> 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! >> 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, 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? >> 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? The effect of CO2 seems greatly over rated, and more should cool more instead of warm.
From: Don Klipstein on 18 Dec 2008 01:12 In <pan.2008.12.08.01.48.50.915298(a)REMOVETHISix.netcom.com>, B. Ward wrote: >On Sun, 07 Dec 2008 07:01:08 +0000, Don Klipstein wrote: > >> In <pan.2008.12.01.17.23.08.108895(a)REMOVETHISix.netcom.com>, B. Ward >> wrote: >>>On Mon, 01 Dec 2008 06:31:17 -0500, Whata Fool wrote: >> >>>> don(a)manx.misty.com (Don Klipstein) wrote: >>> >>>>>In article <pan.2008.11.27.18.38.37.222361(a)REMOVETHISix.netcom.com>, >>>>>Bill Ward wrote: >>> >>><big snip> >>> >>>>>> 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. >>>>> >>>>> 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. >>>>> 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. >>>>> 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. >>>> >>>> Aren't you confusing lapse rate with moisture laden air and >>>> maybe also low pressure caused by precipitation volume reduction of 200 >>>> to one? >> >>>> I don't understand Bill W saying something about lapse rate >>>> depending so much on convection, all air has to do to cool is to >>>> expand, it doesn't have to rise to normalize the lapse rate. >>> >>>If it expands, where can it go but up to the new pressure level? Another >>>way of looking at it is that warm air is less dense than cold air, so it >>>must rise to be replaced by cold air. As it rises, it expands into the >>>lower pressure, cooling in the process. If the lapse rate is low enough >>>that the new temperature is still warmer than the new environment, it >>>repeats. >> >> When a parcel of rising air maintains warmth relative relative to its >> surroundings, that means the local lapse rate is high rather than low. If >> the local lapse rate is low, the the parcel of rising air would quickly >> cool to cooler than its surroundings by cooling not at the local lapse >> rate but at one of the two adiabatic ones (the dry one until/unless cloud >> forms or is present in the rising air parcel, and then cooling as a result >> of rising at the wet one). > >You are right, of course. I got the lapse rate exactly backwards even >though you were clearly referring to the positive convention. My bad. > >My point is that warming the surface will eventually lead to convection as >the temperature exceeds that of the adjacent atmosphere. > >>>>> 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. >>>>> >>>>> Likewise, the Earth's surface receives significant radiation from >>>>> clear >>>>>air below the 500 millibar level. >>>>> >>>>> - Don Klipstein (don(a)misty.com) >> >>>> And convection is what warms that air. The bottom line is that >>>> _IF_ N2 and O2 can't cool without >>>> GreenHouse Gases, then the atmosphere would be warmer than now, >>>> meaning the present GreenHouse Gas theory is faulty, as the basis was >>>> a comparison of Earth and moon temperatures. >> >> The "effective radiation level" without GHGs will be at a much lower >> altitude - with same temperature, to have radiation outgo matching >> radiation income. (Temperature of "effective radiation level" will >> change if such an atmospheric change changes the albedo to incoming >> radiation.) > >Won't daytime clouds always increase albedo? >> >> Even though most of the world usually has mobility in average local >> lapse rate in either direction, there is significant positive >> correlation between surface temperature and height of the "effective >> altitude of radiating to space" as GHG concentration varies. > >Would that be both water vapor and CO2? Or just stratospheric GHGs? > >>>> So when will somebody start thinking, rethink the basics, >>>> and concede that GreenHouse Gases cool the atmosphere? >>> >>>I think they do, but in the process, they keep the surface from cooling >>>as fast as it would otherwise. >> >> GHGs above the "effective average radiating level" do indeed cool such >> higher levels of the atmosphere. >> It is true that GHGs increase ability of the atmosphere to radiate >> heat >> to outer space (or/and-also to GHGs or clouds in other layers of the >> atmosphere and sometimes to surface). >> What - we agree on something? > >Looks like it. Thanks for your patience and coherent explanations. At this late hour at so busy a time of year, best I can say in response here is "You're Welcome", along with: Thanks for honorability in debate. I see too much debate with too much bias - not that I lack bias, but I like to consider myself honest enough to "let facts get in the way". I dispute ones I don't like where I can with further facts and concede them otherwise. Maybe not perfectly - though I think I have done so at least 80% of the way! :) :) :) Other than that, for one thing I learn "atmospheric science" a bit more, though I have already put so much bleeping time and effort into that already, in major part by being a weather nut! I would admist that open reasonably honest debate is not perfectly unbiased - such debate between those trying to maintain status as "honorable opponents" "clears the air" to an extent exposing biases and reqwuiring corrections thereto. I admit that I have a personal bias in favor of existence of AGW. I find that being "tempered" by debate-surviving data on global and regional and specific-atmosphere-level temperatures, trends thereof, .... Along with myself continuing my education as to how Earth's atmosphere works - such as issues of atmospheric radiation balance represented by a specific pressure level (350 mb level globally so far as I have done, and I did mis-calculate 300 mb maybe a week and a half ago or closer to a week ago), and I consider that quite an oversimplification since some wavelengths radiated by ground have majority chance of passing through the atmosphere to deep space and other wavelengths to a notable extent are bogged down by GHGs for outward heat transport by radiation. - Don Klipstein (don(a)misty.com)
From: Bill Ward on 18 Dec 2008 01:59 On Thu, 18 Dec 2008 03:27:28 +0000, Don Klipstein wrote: > In article <pan.2008.12.09.15.55.30.33517(a)REMOVETHISix.netcom.com>, Bill > Ward wrote: >>On Tue, 09 Dec 2008 06:03:54 +0000, 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. ÃÂÃÂ 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. ÃÂÃÂ It's still rising, and >>>>>>>> the resistance is decreased. ÃÂÃÂ 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. >> >>That would require a heat pump. Could you explain the mechanism? > > Global atmospheric circulation driven by troposphere being warmer in the > tropics than around the poles but on a rotating planet gives us such > things as the subtropical jetstreams and subtropical highs. > > The heatpump results, I was thinking more of an explanation of the physics involved in moving heat from a cool spot to a hotter one. Like what the working fluid is, and where the stages of the cycle take place. > and does indeed have a minority of the air > ascending in the ITCZ descending to the surface outside the ITCZ hotter > than cooler. From surface to roughly the 110 mb level, the average > temperature is supposed to be colder where the air descends. The > descending air could cool by radiation - when descended to levels of the > atmosphere with below-avererage GHG overhead (due to being very dry). > Extra heating at some altitudes (sometimes close to surface) results from > descent warming at the greater dry adiabatic lapse rate except for such > air cooling radiationally from its GHGs - which it has less of (due to > being dry), though it has below-average extent of GHG overhead. The air in > hotspots of subtropical highs could even get pushed down by local weather > features, though when "that hot" has to be a small minority in order for > the laws of thermodynamics to hold true. > > Meanwhile, the highest temperatures in Africa and in North America, also > above sea level in North America, are quite far from the equator - I would > dare say at least 27 degrees north latitude, maybe more like closer to 30. > >>>>> And greenhouse gases above the cloudtop will return to the cloud >>>>> some of the cloud's thermal radiation. >>>> >>>>Not net radiation. The net energy flow is always from hot to cold. >>>>Always. >>> >>> GHGs will add impedance to that flow. >> >>And latent heat transport will decrease the impedance. > > And increase thereof will decrease temperature difference between where > the heat comes from and where the heat goes. Much of the air rising in > "tropical deep convection" descends elsewhere in the world, Once the water vapor has been lifted and condensed, the latent heat has been transferred. How can it be transferred downward? First the air has to cool so it can sink. Is there any way other than radiation? > since rising > air in "tropical deep convection" is part of global atmospheric > circulation. Global atmospheric circulation already contributes to the > polar regions being warmer and the tropics being cooler than they > otherwise would be. (Global oceanic circulation also does that - reduced > exposure to global oceanic circulation makes the Red Sea and nearby areas > hotter than otherwise-similar tropical areas.) Is it really that, or the fact that it gets a lot of sun and not much cloud cover? Slowing the cooling rate is not heating. >>>>> And what goes up usually must go down - especially air. The air >>>>> rising >>>>> through the cloud mass of a Nor'Easter will descend somewhere. >>>> >>>> And it's dryer and cooler because of precipitation and radiation. >>> >>> Precipitation cools it? >> >>No, it drys it. >> >>> I thought condensation warms it. But radiation wil cool it. It ends >>> up on ground somewhere, usually cooler than where it came from, and >>> often making the ground warmer than it otherwise would be. >> >>Of course. Heat is transported poleward. > > Very true - I would like to note something we agree on! > >>>>>> The whole notion of somehow "trapping" energy in the atmosphere >>>>>> seems ludicrous. It's either sensible heat, latent heat, or >>>>>> radiation. It doesn't just disappear. >>>>> >>>>> It accumulates until radiator temperatures get sufficient to have >>>>> radiative outgo to outer space match radiative income from the Sun. >> >>If by "accumulating", you mean the temperature increases, yes. The >>radiation is proportion to the 4th power of that temperature. >> >>>>Then it's sensible heat subject to upward convection. >>> >>> It won't convect much until warming achieves lapse rate achieving >>> the >>> relevant adiabatic one. >> >>And accumulating heat will raise the temperature until convection >>begins. >> >>> Most of the atmosphere has lapse rate less than the relevant adiabatic >>> one. >> >>Probably. Half of the atmosphere is in nighttime. Wouldn't you agree >>most heat is transported to the radiative layer during the daytime, when >>temperatures are higher? > > I would agree much more heat gets transported there during daytime > than > at nighttime. > > However, most of the world lacks cloud tops within 4 km of the 350 mb > level, and a lot of the air gettinmg that high or higher manages to not > lose a lot of heat by radiation before it descends - a lot of > radiational cooling of air occurs where its descent requires cooling as > it descends (One good example is polar vortices). Cooling doesn't have to take place equally all over the globe. Of course some areas will cool less effectively than others. Shouldn't the emphasis be on understanding the most effective mechanisms, rather than focusing on places that don't play much of a part? >>>> The temperature is a function of the gas laws and the specific heat >>>> of the air. Warming a parcel of gas doesn't "trap" any radiation. >>> >>> I did not say warming a parcel of gas makes it trap radiation. What >>> I >>> said was that if a parcel of gas was cooler than achieving radiation >>> balance, it will warm from radiation. >> >>True. That warming assists convection. > > What if it warmed where the lapse rate was short of allowing > convection? That describes at least 80% of the troposphere! What if the 20% where it does happen is enough? There seems to be general agreement that climate models don't handle deep tropical convection all that well. Yet that's where most of the cooling happens. It wouldn't take much negative feedback to wipe out the estimated CO2 forcing. >>>>The surface heat flow is in during the day and out at night, only the >>>>net flow is balanced. >>>> >>>>I think you may be confused by the Trenberth energy flow cartoon, >>>>which shows the 45W/m^2 surface IR component as the difference between >>>>upward and downward radiation flows. It's misleading, because no net >>>>heat can ever flow from cold to hot. >>>> >>>>Improperly averaging terms that should be integrated seems to be a >>>>common factor in the "climate science" domain. >>> >>> I am not claiming that there is a long term imbalance between >>> amount of energy income and amount of energy outgo anywhere. An >>> imbalance will result in a temperature change to cause outgo and >>> income to match. >> >>I didn't mean to imply you did. That seems relatively obvious. >> >>We seem to be basically agreeing on several points. > > - Don Klipstein (don(a)misty.com)
From: Bill Ward on 18 Dec 2008 02:08 On Thu, 18 Dec 2008 03:30:28 +0000, Don Klipstein wrote: > 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. ÃâàI 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. ÃâàIt's still rising, and >>>>>>>> the resistance is decreased. ÃâàLift 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. OTOH, if it hadn't warmed, the air would have gone somewhere else. That's the advantage of climate models - you can easily change parameters without realizing they're not independent. But the climate is closed loop with no knobs, and can't do that. > 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: Bill Ward on 18 Dec 2008 02:31
On Thu, 18 Dec 2008 04:51:48 +0000, Don Klipstein wrote: > 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, Remember, the surface is not warming. It has to be in radiative equilibrium with the cooler layer above, which means the net energy flow must still be outward, heating the target layer. It is not cooling as fast as it would if it were radiating directly to space, but it _is_ cooling, not being "warmed" by the cooler 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) |