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uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. |
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#31
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On Dec 10, 5:44*pm, Bill Ward wrote:
On Thu, 10 Dec 2009 07:25:38 -0800, Dawlish wrote: On Dec 10, 2:54*pm, Peter Muehlbauer wrote: Stan and Dawlish You may tell me what you want, CO2 has nothing, absolutely nothing, to do with global warming. Not much use responding with well-respected and cross-referenced temperature data from the last century then that shows that the world has warmed? Of course not. *No one is claiming that climate never changes. *It's the contribution of CO2 that's in question. *You need to show a credible mechanism by which CO2 could affect temperature in the presence of an excess of water. .....................this whole AGW quack obviously a lie. So many deluded peole and so few that really *know* the truth. You need to "show" the truth, not just "know" the truth. *There's a difference. CO2 levels have never varied; solar radiative forcings have an effect but haven't had any effect over the last 2 years; implications that temperature rises since the last ice age have something to do with present GW; I have to give in with you Peter. CO2 has absolutely nothing to do with global warming. Don't you ever ask yourself why so many scientists feel that it has? Lucrative grants? Oh come on Bill, That's not fair to so many conscientious and decent scientists. That simply is not the norm. So far, the responses from denialists have been: a) The established physics are wrong: fair enough, you may think that, but you really would think that so many physicists over the last century would have produced a changed and accepted alternative theory by now, so I find that point of view very difficult to accept. b) The data is wrong, or has been altered: 5 sets of climate data all agreeing make that highly unlikely. c) The atmosphere will take longer than 2 years to lose all the heat gathered over the last 100 years of "doubled" solar activity: that cannot be true as the atmosphere reacts far more quickly than that to changes in ENSO. Heat from the sun is not some kind of special heat that takes longer to disperse! d) Greenhouse gases cause cooling: sorry, but that's just not true. CO2 has a complex absoption spectrum, but it is a strong absorber of IR radiation. More CO2 = more absoption and warming. Accepted fact (by nearly everyone). e) There is a theory that CO2 has always been at pretty much the same concentrations: there's a theory that the earth is flat and that condoms have microscopic holes that allow the AIDS virus through. Both are almost certainly untrue, as is this f) Measured temperatures are stil within the "normal limits" since the Holocene. Whatever has happened prior to the Industrial Revolution cannot be compared to what has happened since, because of the increase in CO2 and because of the massive increases in population. Variations in global temperatures now, however "small" will cause social impacts far greater than changes to post ice-age nomadic societies. g) "Dismissed". Well, go tell that to Copenhagen and especially to leaders of LEDCs whose land surface is low-lying. Lots of denialist ideas, but, typically, no consensus amongst them and nothing that addresses directly my assertion that given the present state of "natural influences" (negative) it ought to be cooler than it is. Every denialist knows they are right, but they can't agree on why and can't produce a convincing single agument that shows that CO2 is not the main driver of global temperature increases. The denialist point of view, expressed here, is just wholly unconvincing - and I'm someone who is prepared to be convinced. Bill's point of view about the physics and the feedbacks could be reasonable, but there are so many scientists working in this field that I cannot believe that the physicists involved haven't realised what he has. The "Lucrative grants?" bit is received wisdom, nut in any way the norm. |
#32
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On Dec 10, 10:52*pm, Bill Ward wrote:
On Thu, 10 Dec 2009 22:22:57 +0100, Rav1ng rabbit wrote: JohnM wrote: On Dec 10, 8:33 pm, Bill Ward wrote: Since clouds are broadband radiators, they efficiently radiate that heat as LWIR from the top of the cloud directly to space, So clouds radiate from the top, but not from the sides or the bottom? Correct. *The sides and bottom are in LTE optically thick air, so no net radiation occurs. I didn't ask about "net" radiation, but I'm sure you are aware of that. So let's try again. Clouds radiate from the top, but not from the sides or the bottom? You can play the "back radiation" game if you want, but I think everyone sees through it now. I see you wrote "it" but, of course, you should've written "me" Don't make it to complicated for Bill, please, don't. Q assumes everyone is as easily confused as he. |
#33
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In article 4d6cb661-317f-45a8-840e-d5f746599fc6
@g12g2000yqa.googlegroups.com, says... Correct. *The sides and bottom are in LTE optically thick air, so no net radiation occurs. I didn't ask about "net" radiation, but I'm sure you are aware of that. So let's try again. Clouds radiate from the top, but not from the sides or the bottom? Where did he say that? I can't find what you are referring to. -- Alan LeHun |
#34
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On Thu, 10 Dec 2009 11:17:20 -0600, Bill Ward
wrote: On Thu, 10 Dec 2009 03:57:22 -0800, Dawlish wrote: On Dec 10, 10:56Â*am, "I M @ good guy" wrote: AGW has to be based on more than the simplistic assumption that CO2 increases causes temperature increases. Obviously it is. CO2 increases will cause temperature increases unless other (natural) factors override the increase which is being caused by increasing CO2. The physics behind that was settled over a century ago. Pumping more CO2 in the earth's atmosphere *will* increase absorption of outgoing IR radiation and it will cause warming. That is accepted by almost all climate scientists and physicists and whether you like it, or not, it is. The greenhouse effect is well understood and the physics behind it really are settled. The degree of warming that will be caused caused by increasing the atmospheric concentration of CO2 is also settled, unless you wish to change those physical laws. That brings me to the point of my original post. Given that the physics is settled, why isn't the earth cooler than it presently is, given that two of the major natural varients (PDO and Solar output) are in a state that ought to mean that they are having a negative effect on temperatures - which they clearly aren't? They should be causing cooling and we should not be experiencing some of the warmest conditions in 130 years - unless the natural effects are *not* managing to override the effects of CO2; which logically leaves CO2 as the main driver of global temperature increase. Unless I (and also the vast majority of climate scientists) see something else affecting global temperatures in a greater way than the physics shows the increases in CO2 should, I'm more likely to strengthen my views on CO2 being the cause of GW, than not. You might want to check your physics. Simple assertion that "it's settled" went out with Al Gore. You need to account for WV, LTE, convection, negative feedbacks, etc, before you will convince anyone. Try explaining rather than just claiming. If anybody wants it colder, they can just come to Chicago and it will be. http://www.chicagotribune.com/news/weather/ |
#35
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On Thu, 10 Dec 2009 18:24:56 +0100, Tom P wrote:
I M @ good guy wrote: On Thu, 10 Dec 2009 05:14:41 -0800 (PST), Dawlish wrote: On Dec 10, 1:00 pm, "Stan" wrote: "I M @ good guy" wrote in messagenews ![]() On Thu, 10 Dec 2009 03:57:22 -0800 (PST), Dawlish wrote: On Dec 10, 10:56 am, "I M @ good guy" wrote: AGW has to be based on more than the simplistic assumption that CO2 increases causes temperature increases. Obviously it is. CO2 increases will cause temperature increases unless other (natural) factors override the increase which is being caused by increasing CO2. The physics behind that was settled over a century ago. Pumping more CO2 in the earth's atmosphere *will* increase absorption of outgoing IR radiation and it will cause warming. That is accepted by almost all climate scientists and physicists and whether you like it, or not, it is. The greenhouse effect is well understood and the physics behind it really are settled. The degree of warming that will be caused caused by increasing the atmospheric concentration of CO2 is also settled, unless you wish to change those physical laws. GHGs are what cool the atmosphere, and all the scientists think the minor trace gas is what warms the atmosphere? Scientists I know don't seem to think this, although they do say that some of the minor gases have a potential greater green house effect. Can you please give me some links so I can read up? (Not that I doubt you but I know several people can read same article and all come up with different conclusions due to selective reading, and may not realise they are doing it, see my reply to article on greenhouse effect on Mars) Also my earlier point regarding graph is that the time scale at bottom is not even but they are evenly spaced. But I agree about your point regarding too small to catch the peaks and troughs etc. That brings me to the point of my original post. Given that the physics is settled, why isn't the earth cooler than it presently is, given that two of the major natural varients (PDO and Solar output) are in a state that ought to mean that they are having a negative effect on temperatures - which they clearly aren't? They should be causing cooling and we should not be experiencing some of the warmest conditions in 130 years - unless the natural effects are *not* managing to override the effects of CO2; which logically leaves CO2 as the main driver of global temperature increase. Unless I (and also the vast majority of climate scientists) see something else affecting global temperatures in a greater way than the physics shows the increases in CO2 should, I'm more likely to strengthen my views on CO2 being the cause of GW, than not. Why isn't it cooler? Maybe if the methods and weather stations used 50 years ago would show more cooling, but if you are cock-sure, no sense in exploring any possible explanations. I agree with Dawlish here, the sun is at a solar Minimum and global climate should be showing, even with global warming, global average temperature heading towards a trough, although with global warming I would expect the min of the trough to be slightly higher than last trough. However with 1998 as starting point there was a slight dip followed by rising i.e. almost steady Taking out the 1998 blip, temperatures have only slowed down in the general rising, and look like they are starting to speed up again. Note to Dawlish and good.guy try and keep tone friendly even if you disagree on this. Debate can be fun even if you think other guy is talking a load of rubbish. I agree entirely with your remarks on keeping the tone reasonable, Stan, even when so many scientists are tarred with a "nucase" brush they simply don't deserve. I don't even believe fully that CO2 is the main driver for GW; I just think, on the basis of evidence, that it is likely to be - unlike guy, who even denies the science and says that GHGs *cool* the atmosphere. Well, I'll just point out again that the vast majority (and I make no apology for using that term again, as it is true) of climate scientists and physicists would regard that as twaddle. Not just me, guy, but almost everyone else. You're joking aren't you? If not, state what you (and the scientists and physicists) think cools the atmosphere after the sun warms it, the outgoing energy has to equal the incoming. [[Please note: I do not call rational scientists names, it is the foul mouthed idiots posting in alt.global-warming nonsense about absolute certainty in AGW]] Ok, here we go - the temperature at which the earth is in radiative equilibrium with the incoming solar energy is around -20°c. How is the facts of that statement derived, is that minus 20 C? This is the temperature of the atmosphere at an altitude of around 6km - I have to say "around", because this varies by latitude, but for the sake of simplicity if we are going to get anywhere in the discussion, we have to stick to averages and approximations. To get anywhere in the science, specifics are needed, not estimates of averages and guess approximations. So, at this altitude, we can say for simplicities sake that the LWR is being emitted by the GHGs in the atmosphere at this altitude. Sorry, LWIR can be leaving the Earth from a lot of different levels at the same time. (There is also a component that gets through from the surface directly in certain spectral bands, which we leave aside). It is between 10 and 20 percent, a little too much to leave aside. That means that in a very strange sense of the word, GHGs "cool" the atmosphere. Not a strange sense at all, without GHGs, the N2 and O2 could not cool much at all. It's an expression that denialists (sorry, sceptics) are fond of using even if it doesn't really mean anything. No, it is the basic physics, the only thing that cools the atmosphere. It's like saying that if I wear an anorak, the anorak "cools" me because my body heat ultimately can only escape from the surface of the anorak... If your anorak had the properties of nitrogen, you would have to open it up or have a heat stroke. That aside, the next thing to note is that the temperature at the surface is always higher than the temperature at the -20°c level as a result of the Lapse Rate. Not as a result of the Lapse Rate, partly because of the sun and partly because heat is migrating from the center of the Earth. And gravity and the mass of the atmosphere is what causes the Lapse Rate. While using an equivalent temperature level may have a use in approximations, it has no bearing on reality and the physics. The Lapse Rate is a consequence of the hydrostatic equation and the gas laws. This is basic physics. The exact amount depends on the amount of water vapour in the atmosphere, but this again is limited by the Clausius-Clapeyron equation, which in turn is derived from the fundamental physics of thermodynamics. A lapse rate can exist without water vapor, I assume you meant the amount or rate of LWIR depends mostly on water vapor. Now, the important thing to note is that the composition of GHGs at this altitude is not the same as the surface. At the surface, the higher temperature allows water vapour to exist in large quantities measurable in percentages. As we go up higher in the atmosphere, the temperature drop (lapse rate) causes the maximum water vapour content to drop dramatically. Again, the relationship between temperature and saturation vapour pressure is determined by Clausius-Clapeyron. That means that at 6km altitude, instead of being the overwhelming GHG ,water vapour is less than 10 times the concentration of CO2 - still higher than CO2, but with the result that changes in the CO2 concentration are by no means negligible, but have a direct effect on the overall greenhouse gas effect. And I will admit not much LWIR makes it to space from exactly that altitude. Note we are talking about the MAXIMUM concentration possible of water vapour - at any moment, the actual concentration can be even lower. I suppose the lower in the atmosphere, the more strict the Local Temperature Equilibrium. I submit that the GHGs alone could not hold enough heat to prevent the temperature from dropping more at night. At higher altitudes the GHGs radiate more to space than reaches low altitudes, trying to deny that GHGs cool the atmosphere does not help the AGW premise in the least. Regardless of how these processes result in retention of heat in the atmosphere, cooling of the atmosphere is done totally and only by the GreenHouse Gases. |
#36
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On Thu, 10 Dec 2009 13:14:55 -0800 (PST), JohnM
wrote: On Dec 10, 8:33Â*pm, Bill Ward wrote: Since clouds are broadband radiators, they efficiently radiate that heat as LWIR from the top of the cloud directly to space, So clouds radiate from the top, but not from the sides or the bottom? Clouds would/could receive more on the bottom than they radiate, while at the top at night, LWIR BB to 3 K space is substantial, in daylight, they reflect enough to be a cooling factor overall. |
#37
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On Thu, 10 Dec 2009 14:05:13 -0800 (PST), Dawlish
wrote: On Dec 10, 5:44Â*pm, Bill Ward wrote: On Thu, 10 Dec 2009 07:25:38 -0800, Dawlish wrote: On Dec 10, 2:54Â*pm, Peter Muehlbauer wrote: Stan and Dawlish You may tell me what you want, CO2 has nothing, absolutely nothing, to do with global warming. Not much use responding with well-respected and cross-referenced temperature data from the last century then that shows that the world has warmed? Of course not. Â*No one is claiming that climate never changes. Â*It's the contribution of CO2 that's in question. Â*You need to show a credible mechanism by which CO2 could affect temperature in the presence of an excess of water. .....................this whole AGW quack obviously a lie. So many deluded peole and so few that really *know* the truth. You need to "show" the truth, not just "know" the truth. Â*There's a difference. CO2 levels have never varied; solar radiative forcings have an effect but haven't had any effect over the last 2 years; implications that temperature rises since the last ice age have something to do with present GW; I have to give in with you Peter. CO2 has absolutely nothing to do with global warming. Don't you ever ask yourself why so many scientists feel that it has? Lucrative grants? Oh come on Bill, That's not fair to so many conscientious and decent scientists. That simply is not the norm. So far, the responses from denialists have been: a) The established physics are wrong: fair enough, you may think that, but you really would think that so many physicists over the last century would have produced a changed and accepted alternative theory by now, so I find that point of view very difficult to accept. b) The data is wrong, or has been altered: 5 sets of climate data all agreeing make that highly unlikely. c) The atmosphere will take longer than 2 years to lose all the heat gathered over the last 100 years of "doubled" solar activity: that cannot be true as the atmosphere reacts far more quickly than that to changes in ENSO. Heat from the sun is not some kind of special heat that takes longer to disperse! d) Greenhouse gases cause cooling: sorry, but that's just not true. CO2 has a complex absoption spectrum, but it is a strong absorber of IR radiation. More CO2 = more absoption and warming. Accepted fact (by nearly everyone). e) There is a theory that CO2 has always been at pretty much the same concentrations: there's a theory that the earth is flat and that condoms have microscopic holes that allow the AIDS virus through. Both are almost certainly untrue, as is this f) Measured temperatures are stil within the "normal limits" since the Holocene. Whatever has happened prior to the Industrial Revolution cannot be compared to what has happened since, because of the increase in CO2 and because of the massive increases in population. Variations in global temperatures now, however "small" will cause social impacts far greater than changes to post ice-age nomadic societies. g) "Dismissed". Well, go tell that to Copenhagen and especially to leaders of LEDCs whose land surface is low-lying. Lots of denialist ideas, but, typically, no consensus amongst them and nothing that addresses directly my assertion that given the present state of "natural influences" (negative) it ought to be cooler than it is. Every denialist knows they are right, but they can't agree on why and can't produce a convincing single agument that shows that CO2 is not the main driver of global temperature increases. The denialist point of view, expressed here, is just wholly unconvincing - and I'm someone who is prepared to be convinced. Bill's point of view about the physics and the feedbacks could be reasonable, but there are so many scientists working in this field that I cannot believe that the physicists involved haven't realised what he has. The "Lucrative grants?" bit is received wisdom, nut in any way the norm. It isn't very smart to deny that GHGs cool the atmosphere, only GHGs cool the atmosphere. While most scientists are conscientious and honest they may be intimidated enough not to rock the boat, but that isn't really an issue, a number of factors could be both causing some warming, and UHI may be a bigger factor in raw data than admitted by the three major units. I would guess sulfur emissions may be an issue, I tried to find recent history, but no luck. I just hope the AGW activists are enjoying temperatures like I am (15 degrees below normal). |
#38
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Bill Ward wrote:
On Thu, 10 Dec 2009 18:24:56 +0100, Tom P wrote: I M @ good guy wrote: On Thu, 10 Dec 2009 05:14:41 -0800 (PST), Dawlish wrote: On Dec 10, 1:00 pm, "Stan" wrote: "I M @ good guy" wrote in messagenews ![]() On Thu, 10 Dec 2009 03:57:22 -0800 (PST), Dawlish wrote: On Dec 10, 10:56 am, "I M @ good guy" wrote: AGW has to be based on more than the simplistic assumption that CO2 increases causes temperature increases. Obviously it is. CO2 increases will cause temperature increases unless other (natural) factors override the increase which is being caused by increasing CO2. The physics behind that was settled over a century ago. Pumping more CO2 in the earth's atmosphere *will* increase absorption of outgoing IR radiation and it will cause warming. That is accepted by almost all climate scientists and physicists and whether you like it, or not, it is. The greenhouse effect is well understood and the physics behind it really are settled. The degree of warming that will be caused caused by increasing the atmospheric concentration of CO2 is also settled, unless you wish to change those physical laws. GHGs are what cool the atmosphere, and all the scientists think the minor trace gas is what warms the atmosphere? Scientists I know don't seem to think this, although they do say that some of the minor gases have a potential greater green house effect. Can you please give me some links so I can read up? (Not that I doubt you but I know several people can read same article and all come up with different conclusions due to selective reading, and may not realise they are doing it, see my reply to article on greenhouse effect on Mars) Also my earlier point regarding graph is that the time scale at bottom is not even but they are evenly spaced. But I agree about your point regarding too small to catch the peaks and troughs etc. That brings me to the point of my original post. Given that the physics is settled, why isn't the earth cooler than it presently is, given that two of the major natural varients (PDO and Solar output) are in a state that ought to mean that they are having a negative effect on temperatures - which they clearly aren't? They should be causing cooling and we should not be experiencing some of the warmest conditions in 130 years - unless the natural effects are *not* managing to override the effects of CO2; which logically leaves CO2 as the main driver of global temperature increase. Unless I (and also the vast majority of climate scientists) see something else affecting global temperatures in a greater way than the physics shows the increases in CO2 should, I'm more likely to strengthen my views on CO2 being the cause of GW, than not. Why isn't it cooler? Maybe if the methods and weather stations used 50 years ago would show more cooling, but if you are cock-sure, no sense in exploring any possible explanations. I agree with Dawlish here, the sun is at a solar Minimum and global climate should be showing, even with global warming, global average temperature heading towards a trough, although with global warming I would expect the min of the trough to be slightly higher than last trough. However with 1998 as starting point there was a slight dip followed by rising i.e. almost steady Taking out the 1998 blip, temperatures have only slowed down in the general rising, and look like they are starting to speed up again. Note to Dawlish and good.guy try and keep tone friendly even if you disagree on this. Debate can be fun even if you think other guy is talking a load of rubbish. I agree entirely with your remarks on keeping the tone reasonable, Stan, even when so many scientists are tarred with a "nucase" brush they simply don't deserve. I don't even believe fully that CO2 is the main driver for GW; I just think, on the basis of evidence, that it is likely to be - unlike guy, who even denies the science and says that GHGs *cool* the atmosphere. Well, I'll just point out again that the vast majority (and I make no apology for using that term again, as it is true) of climate scientists and physicists would regard that as twaddle. Not just me, guy, but almost everyone else. You're joking aren't you? If not, state what you (and the scientists and physicists) think cools the atmosphere after the sun warms it, the outgoing energy has to equal the incoming. [[Please note: I do not call rational scientists names, it is the foul mouthed idiots posting in alt.global-warming nonsense about absolute certainty in AGW]] Ok, here we go - the temperature at which the earth is in radiative equilibrium with the incoming solar energy is around -20°c. This is the temperature of the atmosphere at an altitude of around 6km - I have to say "around", because this varies by latitude, but for the sake of simplicity if we are going to get anywhere in the discussion, we have to stick to averages and approximations. So, at this altitude, we can say for simplicities sake that the LWR is being emitted by the GHGs in the atmosphere at this altitude. (There is also a component that gets through from the surface directly in certain spectral bands, which we leave aside). That means that in a very strange sense of the word, GHGs "cool" the atmosphere. It's an expression that denialists (sorry, sceptics) are fond of using even if it doesn't really mean anything. It's like saying that if I wear an anorak, the anorak "cools" me because my body heat ultimately can only escape from the surface of the anorak... Good analogy. If you were wearing a Dewar flask, you'd melt down, because there'd be no way to lose the heat you generate. That aside, the next thing to note is that the temperature at the surface is always higher than the temperature at the -20°c level as a result of the Lapse Rate. The Lapse Rate is a consequence of the hydrostatic equation and the gas laws. This is basic physics. The exact amount depends on the amount of water vapour in the atmosphere, but this again is limited by the Clausius-Clapeyron equation, which in turn is derived from the fundamental physics of thermodynamics. And the mass of the atmosphere. Now, the important thing to note is that the composition of GHGs at this altitude is not the same as the surface. At the surface, the higher temperature allows water vapour to exist in large quantities measurable in percentages. As we go up higher in the atmosphere, the temperature drop (lapse rate) causes the maximum water vapour content to drop dramatically. Again, the relationship between temperature and saturation vapour pressure is determined by Clausius-Clapeyron. That means that at 6km altitude, instead of being the overwhelming GHG ,water vapour is less than 10 times the concentration of CO2 - still higher than CO2, but with the result that changes in the CO2 concentration are by no means negligible, but have a direct effect on the overall greenhouse gas effect. Note we are talking about the MAXIMUM concentration possible of water vapour - at any moment, the actual concentration can be even lower. Nice description, Tom. You included part of the WV effect, so you're even closer than before. All you need to do now is ask yourself where the WV went as it convected upward. I'm sure you'll immediately realize it condensed into clouds and released the latent heat it absorbed from the surface. Otherwise there'd have to be the same concentration aloft as below. Since clouds are broadband radiators, they efficiently radiate that heat as LWIR from the top of the cloud directly to space, because, as you pointed out, there is very little WV remaining at high altitudes to absorb it. The warmer the surface, the more WV (higher specific humidity), so the condensation temperature (dew point) is higher, causing clouds and radiation to occur at a lower altitude. That increases the radiated power by the S/B T^4 relation, so forms a strong negative feedback. The warmer the surface, the stronger the cooling effect. Any small change in 15u CO2 emission is easily swamped out by that regulating mechanism, so CO2 can't have much of an effect on surface temperature. That's set by the properties of water and the mass of the atmosphere, via the lapse rate. Congratulations on your progress. You may be ready to try Miskolczi again: http://www.landshape.org/dokuwiki/doku.php?id=introduction (Dr. Noor van Andel) http://www.met.hu/doc/idojaras/vol111001_01.pdf (Dr. Ferenc Miskolczi) Bill, if you could finally get round to the idea that there are climate researchers in the world, and Miskolczi is not one of them, you could make a lot of progress. |
#39
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On Fri, 11 Dec 2009 06:57:27 +0100, Tom P wrote:
Bill Ward wrote: On Thu, 10 Dec 2009 18:24:56 +0100, Tom P wrote: I M @ good guy wrote: On Thu, 10 Dec 2009 05:14:41 -0800 (PST), Dawlish wrote: On Dec 10, 1:00 pm, "Stan" wrote: "I M @ good guy" wrote in messagenews ![]() On Thu, 10 Dec 2009 03:57:22 -0800 (PST), Dawlish wrote: On Dec 10, 10:56 am, "I M @ good guy" wrote: AGW has to be based on more than the simplistic assumption that CO2 increases causes temperature increases. Obviously it is. CO2 increases will cause temperature increases unless other (natural) factors override the increase which is being caused by increasing CO2. The physics behind that was settled over a century ago. Pumping more CO2 in the earth's atmosphere *will* increase absorption of outgoing IR radiation and it will cause warming. That is accepted by almost all climate scientists and physicists and whether you like it, or not, it is. The greenhouse effect is well understood and the physics behind it really are settled. The degree of warming that will be caused caused by increasing the atmospheric concentration of CO2 is also settled, unless you wish to change those physical laws. GHGs are what cool the atmosphere, and all the scientists think the minor trace gas is what warms the atmosphere? Scientists I know don't seem to think this, although they do say that some of the minor gases have a potential greater green house effect. Can you please give me some links so I can read up? (Not that I doubt you but I know several people can read same article and all come up with different conclusions due to selective reading, and may not realise they are doing it, see my reply to article on greenhouse effect on Mars) Also my earlier point regarding graph is that the time scale at bottom is not even but they are evenly spaced. But I agree about your point regarding too small to catch the peaks and troughs etc. That brings me to the point of my original post. Given that the physics is settled, why isn't the earth cooler than it presently is, given that two of the major natural varients (PDO and Solar output) are in a state that ought to mean that they are having a negative effect on temperatures - which they clearly aren't? They should be causing cooling and we should not be experiencing some of the warmest conditions in 130 years - unless the natural effects are *not* managing to override the effects of CO2; which logically leaves CO2 as the main driver of global temperature increase. Unless I (and also the vast majority of climate scientists) see something else affecting global temperatures in a greater way than the physics shows the increases in CO2 should, I'm more likely to strengthen my views on CO2 being the cause of GW, than not. Why isn't it cooler? Maybe if the methods and weather stations used 50 years ago would show more cooling, but if you are cock-sure, no sense in exploring any possible explanations. I agree with Dawlish here, the sun is at a solar Minimum and global climate should be showing, even with global warming, global average temperature heading towards a trough, although with global warming I would expect the min of the trough to be slightly higher than last trough. However with 1998 as starting point there was a slight dip followed by rising i.e. almost steady Taking out the 1998 blip, temperatures have only slowed down in the general rising, and look like they are starting to speed up again. Note to Dawlish and good.guy try and keep tone friendly even if you disagree on this. Debate can be fun even if you think other guy is talking a load of rubbish. I agree entirely with your remarks on keeping the tone reasonable, Stan, even when so many scientists are tarred with a "nucase" brush they simply don't deserve. I don't even believe fully that CO2 is the main driver for GW; I just think, on the basis of evidence, that it is likely to be - unlike guy, who even denies the science and says that GHGs *cool* the atmosphere. Well, I'll just point out again that the vast majority (and I make no apology for using that term again, as it is true) of climate scientists and physicists would regard that as twaddle. Not just me, guy, but almost everyone else. You're joking aren't you? If not, state what you (and the scientists and physicists) think cools the atmosphere after the sun warms it, the outgoing energy has to equal the incoming. [[Please note: I do not call rational scientists names, it is the foul mouthed idiots posting in alt.global-warming nonsense about absolute certainty in AGW]] Ok, here we go - the temperature at which the earth is in radiative equilibrium with the incoming solar energy is around -20°c. This is the temperature of the atmosphere at an altitude of around 6km - I have to say "around", because this varies by latitude, but for the sake of simplicity if we are going to get anywhere in the discussion, we have to stick to averages and approximations. So, at this altitude, we can say for simplicities sake that the LWR is being emitted by the GHGs in the atmosphere at this altitude. (There is also a component that gets through from the surface directly in certain spectral bands, which we leave aside). That means that in a very strange sense of the word, GHGs "cool" the atmosphere. It's an expression that denialists (sorry, sceptics) are fond of using even if it doesn't really mean anything. It's like saying that if I wear an anorak, the anorak "cools" me because my body heat ultimately can only escape from the surface of the anorak... Good analogy. If you were wearing a Dewar flask, you'd melt down, because there'd be no way to lose the heat you generate. That aside, the next thing to note is that the temperature at the surface is always higher than the temperature at the -20°c level as a result of the Lapse Rate. The Lapse Rate is a consequence of the hydrostatic equation and the gas laws. This is basic physics. The exact amount depends on the amount of water vapour in the atmosphere, but this again is limited by the Clausius-Clapeyron equation, which in turn is derived from the fundamental physics of thermodynamics. And the mass of the atmosphere. Now, the important thing to note is that the composition of GHGs at this altitude is not the same as the surface. At the surface, the higher temperature allows water vapour to exist in large quantities measurable in percentages. As we go up higher in the atmosphere, the temperature drop (lapse rate) causes the maximum water vapour content to drop dramatically. Again, the relationship between temperature and saturation vapour pressure is determined by Clausius-Clapeyron. That means that at 6km altitude, instead of being the overwhelming GHG ,water vapour is less than 10 times the concentration of CO2 - still higher than CO2, but with the result that changes in the CO2 concentration are by no means negligible, but have a direct effect on the overall greenhouse gas effect. Note we are talking about the MAXIMUM concentration possible of water vapour - at any moment, the actual concentration can be even lower. Nice description, Tom. You included part of the WV effect, so you're even closer than before. All you need to do now is ask yourself where the WV went as it convected upward. I'm sure you'll immediately realize it condensed into clouds and released the latent heat it absorbed from the surface. Otherwise there'd have to be the same concentration aloft as below. Since clouds are broadband radiators, they efficiently radiate that heat as LWIR from the top of the cloud directly to space, because, as you pointed out, there is very little WV remaining at high altitudes to absorb it. The warmer the surface, the more WV (higher specific humidity), so the condensation temperature (dew point) is higher, causing clouds and radiation to occur at a lower altitude. That increases the radiated power by the S/B T^4 relation, so forms a strong negative feedback. The warmer the surface, the stronger the cooling effect. Any small change in 15u CO2 emission is easily swamped out by that regulating mechanism, so CO2 can't have much of an effect on surface temperature. That's set by the properties of water and the mass of the atmosphere, via the lapse rate. Congratulations on your progress. You may be ready to try Miskolczi again: http://www.landshape.org/dokuwiki/doku.php?id=introduction (Dr. Noor van Andel) http://www.met.hu/doc/idojaras/vol111001_01.pdf (Dr. Ferenc Miskolczi) Bill, if you could finally get round to the idea that there are climate researchers in the world, and Miskolczi is not one of them, you could make a lot of progress. Hey, research away, just don't ask me to pay extra unless you can send some warmer weather this direction, I will pay for warmer weather gladly. |
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I M @ good guy wrote:
On Thu, 10 Dec 2009 18:24:56 +0100, Tom P wrote: I M @ good guy wrote: On Thu, 10 Dec 2009 05:14:41 -0800 (PST), Dawlish wrote: On Dec 10, 1:00 pm, "Stan" wrote: "I M @ good guy" wrote in messagenews ![]() On Thu, 10 Dec 2009 03:57:22 -0800 (PST), Dawlish wrote: On Dec 10, 10:56 am, "I M @ good guy" wrote: AGW has to be based on more than the simplistic assumption that CO2 increases causes temperature increases. Obviously it is. CO2 increases will cause temperature increases unless other (natural) factors override the increase which is being caused by increasing CO2. The physics behind that was settled over a century ago. Pumping more CO2 in the earth's atmosphere *will* increase absorption of outgoing IR radiation and it will cause warming. That is accepted by almost all climate scientists and physicists and whether you like it, or not, it is. The greenhouse effect is well understood and the physics behind it really are settled. The degree of warming that will be caused caused by increasing the atmospheric concentration of CO2 is also settled, unless you wish to change those physical laws. GHGs are what cool the atmosphere, and all the scientists think the minor trace gas is what warms the atmosphere? Scientists I know don't seem to think this, although they do say that some of the minor gases have a potential greater green house effect. Can you please give me some links so I can read up? (Not that I doubt you but I know several people can read same article and all come up with different conclusions due to selective reading, and may not realise they are doing it, see my reply to article on greenhouse effect on Mars) Also my earlier point regarding graph is that the time scale at bottom is not even but they are evenly spaced. But I agree about your point regarding too small to catch the peaks and troughs etc. That brings me to the point of my original post. Given that the physics is settled, why isn't the earth cooler than it presently is, given that two of the major natural varients (PDO and Solar output) are in a state that ought to mean that they are having a negative effect on temperatures - which they clearly aren't? They should be causing cooling and we should not be experiencing some of the warmest conditions in 130 years - unless the natural effects are *not* managing to override the effects of CO2; which logically leaves CO2 as the main driver of global temperature increase. Unless I (and also the vast majority of climate scientists) see something else affecting global temperatures in a greater way than the physics shows the increases in CO2 should, I'm more likely to strengthen my views on CO2 being the cause of GW, than not. Why isn't it cooler? Maybe if the methods and weather stations used 50 years ago would show more cooling, but if you are cock-sure, no sense in exploring any possible explanations. I agree with Dawlish here, the sun is at a solar Minimum and global climate should be showing, even with global warming, global average temperature heading towards a trough, although with global warming I would expect the min of the trough to be slightly higher than last trough. However with 1998 as starting point there was a slight dip followed by rising i.e. almost steady Taking out the 1998 blip, temperatures have only slowed down in the general rising, and look like they are starting to speed up again. Note to Dawlish and good.guy try and keep tone friendly even if you disagree on this. Debate can be fun even if you think other guy is talking a load of rubbish. I agree entirely with your remarks on keeping the tone reasonable, Stan, even when so many scientists are tarred with a "nucase" brush they simply don't deserve. I don't even believe fully that CO2 is the main driver for GW; I just think, on the basis of evidence, that it is likely to be - unlike guy, who even denies the science and says that GHGs *cool* the atmosphere. Well, I'll just point out again that the vast majority (and I make no apology for using that term again, as it is true) of climate scientists and physicists would regard that as twaddle. Not just me, guy, but almost everyone else. You're joking aren't you? If not, state what you (and the scientists and physicists) think cools the atmosphere after the sun warms it, the outgoing energy has to equal the incoming. [[Please note: I do not call rational scientists names, it is the foul mouthed idiots posting in alt.global-warming nonsense about absolute certainty in AGW]] Ok, here we go - the temperature at which the earth is in radiative equilibrium with the incoming solar energy is around -20°c. How is the facts of that statement derived, is that minus 20 C? This is the temperature of the atmosphere at an altitude of around 6km - I have to say "around", because this varies by latitude, but for the sake of simplicity if we are going to get anywhere in the discussion, we have to stick to averages and approximations. To get anywhere in the science, specifics are needed, not estimates of averages and guess approximations. So, at this altitude, we can say for simplicities sake that the LWR is being emitted by the GHGs in the atmosphere at this altitude. Sorry, LWIR can be leaving the Earth from a lot of different levels at the same time. (There is also a component that gets through from the surface directly in certain spectral bands, which we leave aside). It is between 10 and 20 percent, a little too much to leave aside. That means that in a very strange sense of the word, GHGs "cool" the atmosphere. Not a strange sense at all, without GHGs, the N2 and O2 could not cool much at all. It's an expression that denialists (sorry, sceptics) are fond of using even if it doesn't really mean anything. No, it is the basic physics, the only thing that cools the atmosphere. It's like saying that if I wear an anorak, the anorak "cools" me because my body heat ultimately can only escape from the surface of the anorak... If your anorak had the properties of nitrogen, you would have to open it up or have a heat stroke. That aside, the next thing to note is that the temperature at the surface is always higher than the temperature at the -20°c level as a result of the Lapse Rate. Not as a result of the Lapse Rate, partly because of the sun and partly because heat is migrating from the center of the Earth. Heat flux from the earth's core is egligible. Do a little research before making such statements. And gravity and the mass of the atmosphere is what causes the Lapse Rate. Correct! It's called the hydrostatic equation. While using an equivalent temperature level may have a use in approximations, it has no bearing on reality and the physics. Interesting statement. Perhaps you should tell that to a meteorologist. The Lapse Rate is a consequence of the hydrostatic equation and the gas laws. This is basic physics. The exact amount depends on the amount of water vapour in the atmosphere, but this again is limited by the Clausius-Clapeyron equation, which in turn is derived from the fundamental physics of thermodynamics. A lapse rate can exist without water vapor, I assume you meant the amount or rate of LWIR depends mostly on water vapor. Assume what you like, that's not what I said. Now, the important thing to note is that the composition of GHGs at this altitude is not the same as the surface. At the surface, the higher temperature allows water vapour to exist in large quantities measurable in percentages. As we go up higher in the atmosphere, the temperature drop (lapse rate) causes the maximum water vapour content to drop dramatically. Again, the relationship between temperature and saturation vapour pressure is determined by Clausius-Clapeyron. That means that at 6km altitude, instead of being the overwhelming GHG ,water vapour is less than 10 times the concentration of CO2 - still higher than CO2, but with the result that changes in the CO2 concentration are by no means negligible, but have a direct effect on the overall greenhouse gas effect. And I will admit not much LWIR makes it to space from exactly that altitude. What is that supposed to mean? Note we are talking about the MAXIMUM concentration possible of water vapour - at any moment, the actual concentration can be even lower. I suppose the lower in the atmosphere, the more strict the Local Temperature Equilibrium. I submit that the GHGs alone could not hold enough heat to prevent the temperature from dropping more at night. The thermal inertia of the atmosphere is around 8 days, I have a reference in a textbook somewhere, I'm travelling right now. At higher altitudes the GHGs radiate more to space than reaches low altitudes, what does that mean? trying to deny that GHGs cool the atmosphere does not help the AGW premise in the least. Regardless of how these processes result in retention of heat in the atmosphere, cooling of the atmosphere is done totally and only by the GreenHouse Gases. ? GHGs are also the reason why the atmosphere warms in the first place, which you neglect to mention. Please explain exactly what you mean by this statement, and what conclusion do you think we should all draw from this statement. Are you perhaps trying to tell us that increasing the amount of GHGs would increase the so-called cooling effect? In that case you are trying to deceive us, because it is simply not true. |
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