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Post by julianb on Jun 13, 2009 12:07:42 GMT
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Post by glc on Jun 13, 2009 12:45:21 GMT
that should be read in conjunction with it, it explains the recent findings of plasma currents circling the globe equatorialy.
So the Sun affects the region where we 've actually seen the least temperature change over the last ~100 years. There's a bit to go before this one pushes AGW aside.
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Post by northsphinx on Jun 13, 2009 13:32:31 GMT
Sorry that i do not manage to explain clearly glc. I try again then. I agree to this: (i) If Incoming Solar = Outgoing LW - we have 'stable' temperatures (ii) If Incoming Solar > Outgoing LW - we have warming (iii) If Incoming Solar < Outgoing LW - we have cooling Agree. 100% Simple heatbalance. "Now if the earth's average surface temperature is ~15 deg (i.e. 288K) then the surface is emitting ~390 w/m2 to space. " This is not right. I refrace to The earth's average surface temperature is ~15 deg (i.e. 288K) then the surface is emitting ~390 w/m2 to the atmosphere. But the atmosphere is not emitting net ~390 w/m2 to space. That is the BIG differance. Some is emittet back to earth.... By clouds for example... The differance IS the greenhouse effect. As You write Yourself: "~240 w/m2 LW radiation is emitted to space from the earth's atmosphere (and surface)." So net is ~240 w/m2 from mostly the atmosphere to space. Roughly the temperature at 500mb height of the atmosphere. Thermally in the middle of the atmosphere. I am not surprised... "This clearly shows that something, which has nothing to do with the distribution of sunlight on the earth's surface, is happening between the surface and the "top of the atmosphere"." Yes the temperature drops in the atmosphere in height. And the atmosphere absorbs heat and emitts heat. From warmer to colder. The heat is radiated out not direct from surface to space but from the atmosphere. !You keep mentioning clouds. But the incoming solar insolation has already accounted for the reflectance of clouds. ! No they are not. The maximum on the surface is about 1000w/m2 but without clouds. If there was a 100% clear sky would that be about ~240 w/m2 at the surface due tho the earths form as You previously wrote. The clouds change that number significally. With clouds is the albedo much different and more of the incoming is reflected out without participating in any heating. On Earth at least. So the real average is actually less than ~240 w/m2 "Clouds do contribute to the greenhouse effect as we know from their warming effects on a winter's night." Warming in winter nights yes but cooling in rest of the years daytime. Look at the earth and see how much average winter it is. Since it is a globe is it a small part of the earth that have winter. Most of the earth do not know about winter. And half the globe will have night. But since the not average but real radiation from a sunny sky is much higher than outgoing radiation in winter night will clouds be a cooling the earth. You wrote: "What "outgoing" are you referring to? There is the direct reflectance but there is also LW emission. There is a difference." I mean infrared heat from cold clouds. Clouds which is water or ice not vapor. High clouds have a temperature in this range. Measured daily by satellites "An average of around 240 w/m2 comes in and an average of around 240 w/m2 goes out. The fact that the surface emits an average of around 390 w/m2 is almost certainly due to the presence of greenhoues gases in the atmosphere. If anyone has a more convincing explanation then I'll be glad to hear it." The surface emits at this temperature/output yes. But not to space direct. There is a colder atmosphere with clouds in between surface and space. The net to space is from the atmosphere which is much colder than the surface. This is the greenhouse effect. The atmosphere is colder than the surface where the net radiation goes out in space. And that is nearly 100% due to water vapor forming clouds. The condensation of vapor is the most important climate force in the atmosphere and CO2 do not condensate in the atmosphere.
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Post by socold on Jun 13, 2009 15:47:16 GMT
If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense.
The Earth's surface only absorbs about 170wm-2 sunlight on average and loses about 100wm-2 through evaporation and convection. That would leave the Earth's surface at minus 85 degree C. This is a totally unrealistic result.
Changing the evaporation and convection rate isn't enough to help. For example dropping both down the lowest they can go - to zero - leaves the Earth's surface at about minus 40 degrees C. It's still substantially lower than Earth's actual surface temperature.
Okay what about sunlight absorbed by the atmosphere? Well that makes the atmosphere warmer, but how is this energy transfered to the surface? Backradiation? Well that's the only option left to us. Lets go for it.
Lets throw half of the atmosphere's radiation down to the surface. The atmosphere gains about 100wm-2 from convection and evaporation from the surface and about 67wm-2 from sunlight. That's 167wm-2 in all. It would be a lot more if we included the absorbed surface radiation, but we are incorrectly ignoring the greenhouse effect so we won't do that.
So lets throw 84wm-2 at the surface. Now it's gaining about 252wm-2. But it's still it's too cold, minus 15 degrees C
There are a few other things to try, but it's not as if noone has ventured into these calculations before. The end of the story is that no matter how much you play with clouds, convection, sunlight, etc you will not be able to account for the surface temperature of the Earth while also ignoring the significant effect of infrared absorption by greenhouse gases in the atmosphere.
Ultimately evaporation and convection only act to cool the surface. Only absorbed sunlight and backradiation from the atmosphere can warm the surface.
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Post by nautonnier on Jun 13, 2009 16:55:56 GMT
Icefisher and Northsphinx: I've been wondering whether or not to respond to your posts and have decided to give it a go. First let me say that clouds do play a part in the enhanced heating of the earth's surface but not in the way you both appear to think. When calculating energy fluxes it's normal to deal with averages. It's true that the earth's atmosphere does receive ~1360 w/m2 but around 30% of this is reflected directly back into space and so plays no part in heating the surface or the atmosphere. This leaves about 960 w/m2. But only one point will receive this amount at any one time. The rest of the earth will either be in darkness, or will only receive a fraction (depending on the angle of incidence) of the 960 w/m2. In fact, the area of the earth which receives the full 960 w/m2 at any one time is equivalent to the X-sectional area of the earth (i.e. PI x R 2), whereas the total surface of the earth can be represented as the surface of sphere (i.e 4 x PI x R 2). The average solar insolation, therefore, is approximately 240 w/m2 (i.e. 1/4 of the direct solar energy). It's probably closer to the figure I wrote in the earler post, i.e. 235 w/m2, but we'll stick with 240 w/m2 for the sake of simplicity. So we have 240 w/m2 incoming radiation which, to maintain a stable climate, is balanced by 240 w/m2 outgoing (LW) radiation. If the earth had no atmosphere, then the 240 w/m2 would would reach the earth, warm the surface and emit 240 w/m2 back to space. But, using the S-B Law, it's simple to calculate that the temperature required to emit 240 w/m2 is only 255K (or -18 deg C) yet the average temperature of the earth is ~33 deg warmer than this. The energy emitted by a body at this temperature is ~390 w/m2 (again using S-B). Clearly the IR absorbing gases in the atmosphere are playing a significant part in maintaining a warm, habitable climate. Water Vapour is the dominant player, but CO2 contributes ~20% to the total warming. This varies between ~9% and ~26% depending on the humidity of the air. It's also thought, by some at least, that if there were less CO2 in the atmosphere there would be a lot less water vapour (warm air holds more water than cold air) and, conversely, there will be a lot more water vapour if there is more CO2 in the atmosphere. This is what's known as a positive feedback. But even with no feedback, doubling the amount of CO2 in the atmosphere is still likely to raise the earth's average temperature by ~1 deg C. You will recognize glc on holiday - he is the one sunbathing when there is solid cloud cover.
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Post by nautonnier on Jun 13, 2009 17:07:14 GMT
If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense. The Earth's surface only absorbs about 170wm-2 sunlight on average and loses about 100wm-2 through evaporation and convection. That would leave the Earth's surface at minus 85 degree C. This is a totally unrealistic result. Changing the evaporation and convection rate isn't enough to help. For example dropping both down the lowest they can go - to zero - leaves the Earth's surface at about minus 40 degrees C. It's still substantially lower than Earth's actual surface temperature. Okay what about sunlight absorbed by the atmosphere? Well that makes the atmosphere warmer, but how is this energy transfered to the surface? Backradiation? Well that's the only option left to us. Lets go for it. Lets throw half of the atmosphere's radiation down to the surface. The atmosphere gains about 100wm-2 from convection and evaporation from the surface and about 67wm-2 from sunlight. That's 167wm-2 in all. It would be a lot more if we included the absorbed surface radiation, but we are incorrectly ignoring the greenhouse effect so we won't do that. So lets throw 84wm-2 at the surface. Now it's gaining about 252wm-2. But it's still it's too cold, minus 15 degrees C There are a few other things to try, but it's not as if noone has ventured into these calculations before. The end of the story is that no matter how much you play with clouds, convection, sunlight, etc you will not be able to account for the surface temperature of the Earth while also ignoring the significant effect of infrared absorption by greenhouse gases in the atmosphere. Ultimately evaporation and convection only act to cool the surface. Only absorbed sunlight and backradiation from the atmosphere can warm the surface. " If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense."Don't ignore it - just remove CO 2 and run the calculations using water vapour as a GHG - then you will find that everything fits quite well. Your error is the strawman claim that CO 2 is the sole GHG.
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Post by glc on Jun 13, 2009 17:07:29 GMT
"Now if the earth's average surface temperature is ~15 deg (i.e. 288K) then the surface is emitting ~390 w/m2 to space. " This is not right. I refrace to The earth's average surface temperature is ~15 deg (i.e. 288K) then the surface is emitting ~390 w/m2 to the atmosphere. But the atmosphere is not emitting net ~390 w/m2 to space. That is the BIG differance.
You are correct here. I didn't mean "to space" I meant "to the atmosphere". That was misleading on my part. Although about 40 w/m2 does escape directly through the IR window.
Having read your post, I don't think there's much disagreement between us, apart from the fact you seem to attribute all outgoing IR absorption to clouds and water vapour and none to CO2.
The surface emits at this temperature/output yes. But not to space direct.
Apart from ~40 w/m2 which is outside the absorption bands of the "greenhouse" gases.
This is the greenhouse effect. The atmosphere is colder than the surface where the net radiation goes out in space. And that is nearly 100% due to water vapor forming clouds. The condensation of vapor is the most important climate force in the atmosphere and CO2 do not condensate in the atmosphere.
But earth's emission spectra clearly shows significant emission from CO2 bands at altitudes (220 K) where concentrations of water vapour are much reduced. I think you may be under-estimating the role of CO2.
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Post by northsphinx on Jun 13, 2009 18:33:51 GMT
"
But earth's emission spectra clearly shows significant emission from CO2 bands at altitudes (220 K) where concentrations of water vapor are much reduced. I think you may be under-estimating the role of CO2. But this IS the flaw. Most of the vapor in the atmosphere is in lower altitudes. With higher temperatures. The CO2 is well mixed in the atmosphere. The definition of a greenhouse gas is that it absorbs IR. But it also emits with a typical signature. Depending on temperature. The earth emission spectra must show this in one way or another. IF you divide the atmosphere in thin layer will each layer be colder than the underlaying one but still in heat balance. IF CO2 is 100% efficient will the cold space see the top layer whit the coldest temperature. That is about guess what? yes 220 K. Precisly as the earth spectrum show. The spectrum show which the greenhouse gasses are and which temperature they are seen from space. And we are talking about gasses now as vapor in the lower altitudes. Not ice and water in clouds.
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Post by dmapel on Jun 13, 2009 23:58:24 GMT
glc: "I though I had given my opinion/estimate. I reckon that by doubling the CO2 in the atmosphere we will raise the global temperature by about 1 deg C (in total). This is pretty much what Barrett says and also what Richard Lindzen says. This is what h e wrote on WUWT a few weeks ago:"
Yes I had a recollection that you mentioned 1C, but I was unclear about whether that was the total expected warming, including feedbacks. Seems well within the bounds of reason to me. From the contentiousness of some of your exchanges with the more skeptical here, one might at first glance be misled to think that you are one of the warmista brothers, who have been sent here by surrealclimate to muddy the waters and defend the faith. I won't mention any names.
Anyway, I believe that 1C is "very likely" near the upper limit on any warming that would result from doubling CO2, because the net of all feedbacks is obviously not positive. So why are they trying to scare our kids with dead polar bears and tax us back into the Stone Age?
Despite your patient efforts, I don't think you are succeeding at leading most of us knuckleheads here to understanding that 1C is the number. Those guys on realclimate and other warmista blogs seem to be pretty smart. May I suggest that your time would be better spent in straightening them out? (half in jest)
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Post by dmapel on Jun 14, 2009 0:02:25 GMT
soclod: "If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense."
nautonnier: "Don't ignore it - just remove CO2 and run the calculations using water vapour as a GHG - then you will find that everything fits quite well.
Your error is the strawman claim that CO2 is the sole GHG."
You have summed up soclod very succinctly. He should leave now.
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Post by julianb on Jun 14, 2009 7:21:42 GMT
glc, obviously you didn't catch on, or didn't read the links.
An energetic plasma in the equatorial band pushes the polar jet streams towards the poles, allowing warmer weather systems to expand north and south. The warm period. When the Sun is quiet, as now, reduced current in the equatorial band allows the polar jet streams to move towards the equator, as we are seeing in Europe, Canada, and Australia and New Zealand, even Brazil has had corn crops affected by frost. The cool period.
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Post by glc on Jun 14, 2009 10:22:07 GMT
glc, obviously you didn't catch on, or didn't read the links.
You're right - sorry - I hadn't read the link. But I have now and Joanna Haigh's comment sums it up where she basically says the findings can't explain fluctuations over the past 50 years. I think Joanna is being rather cautious here. I don't think it can explain temperatures over the last 150 years. Joanna Haigh can't say this, though, because that will compromise the IPCC "Detection and Attribution" studies which say that an increase in solar forcing was at least partly responsible for the early 20th century warming. You see the problem for them is that there was not enough CO2 to take the blame in the 1910-1945 period.
Joanna Haigh has appeared on BBC televison and is a strong supporter of the IPCC consensus. Leif Svalgaard and other solar scientists have now come to the conclusion that the sun has not varied as much as previously thought over the last 400 years. This is increasingly becoming the mainstream view. But this is not good news for the AGWers. With the old outdated reconstructions, they could justifiably claim that there were increases in solar activity in the early 1900s, but none since ~1960. The old solar-climate connection (conveniently for them) broke down in the 1980s.
Don't get me wrong. I'm sure that solar changes do show up in different signals on earth. I'm just not convinced that the sun can explain the recent sustained warming (and cooling) periods seen in the last 100 years. There was no fall in solar activity in the early 1940s yet temperatures fell off a cliff. The most recent solar cycle (SC23) was not a particularly strong cycle and it has been on the go since 1996. The last 'strong' cycle (SC 22) peaked in 1990, since when solar activity has been declining. That's nearly 20 years ago. It's claimed that the weak Dalton Minimum cycles caused a drop in NH temperatures - yet any temperature fall had begun almost 20 years before the start of SC5.
If someone can show that the sun drives ocean circulation then we might have found a mechanism.
Just thought of something else to add: There's a commonly held view that AGWers deny that the sun has an influence on climate. On the contrary, they will be quite happy to use the "quiet sun" if global temperatures remain flat or even fall slightly. And if temperatures happen to start rising again they'll have the best of all worlds. A sleepy sun and rising temperatures - perfect. You can just imagine the triumphant warmings "wait until the sun picks up again - and then see what happens". The solarphiles are in danger of backing themselves into a corner.
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Post by socold on Jun 14, 2009 11:22:15 GMT
If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense. The Earth's surface only absorbs about 170wm-2 sunlight on average and loses about 100wm-2 through evaporation and convection. That would leave the Earth's surface at minus 85 degree C. This is a totally unrealistic result. Changing the evaporation and convection rate isn't enough to help. For example dropping both down the lowest they can go - to zero - leaves the Earth's surface at about minus 40 degrees C. It's still substantially lower than Earth's actual surface temperature. Okay what about sunlight absorbed by the atmosphere? Well that makes the atmosphere warmer, but how is this energy transfered to the surface? Backradiation? Well that's the only option left to us. Lets go for it. Lets throw half of the atmosphere's radiation down to the surface. The atmosphere gains about 100wm-2 from convection and evaporation from the surface and about 67wm-2 from sunlight. That's 167wm-2 in all. It would be a lot more if we included the absorbed surface radiation, but we are incorrectly ignoring the greenhouse effect so we won't do that. So lets throw 84wm-2 at the surface. Now it's gaining about 252wm-2. But it's still it's too cold, minus 15 degrees C There are a few other things to try, but it's not as if noone has ventured into these calculations before. The end of the story is that no matter how much you play with clouds, convection, sunlight, etc you will not be able to account for the surface temperature of the Earth while also ignoring the significant effect of infrared absorption by greenhouse gases in the atmosphere. Ultimately evaporation and convection only act to cool the surface. Only absorbed sunlight and backradiation from the atmosphere can warm the surface. " If we ignore the greenhouse effect and only include convection, evaporation, clouds and sunlight then the Earth's temperature makes no sense."Don't ignore it - just remove CO 2 and run the calculations using water vapour as a GHG - then you will find that everything fits quite well. So where are the calculations that you must have made or seen to come to this conclusion? Your error, I suspect, is making stuff up.
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Post by socold on Jun 14, 2009 11:26:47 GMT
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Post by northsphinx on Jun 14, 2009 12:05:15 GMT
Another flaw in the greenhouse. Stratosphere or more precise the stratopause is the ceiling for the troposphere where the weather is located. Above the troposphere is the temperature rising by altitude and by that efficient make a worldwide inversion layer for the troposphere The stratopause is located higher in the tropics than at the poles. Which have the effect that the minimum temperature in the troposphere is lower because of higher altitudes in the tropics than at the poles. Hmmm And the stratosphere is heated by the sun. Why on earth is then the stratosphere still at low altitudes at the poles in the winter? Without ANY sun? The stratospheres should be cooling in a day or two. That would mean that the stratopause would be high in altitude at the poles. And very low in the tropics. Still it is the opposite. 7-8km at the poles and up to 17-20 km in the tropics. It must be heated by something else than direct sunlight. Something that can reach the stratosphere even in dark winter. And not reach the tropical layer in daytime. It cant obvious be from underneath. There must be something close to the poles that efficiently heat the stratosphere. More efficiently than in the tropics. I believe it must be something that the earths magnetic poles interact with. Something like the solar electrical and magnetic activity interact with earths magnetic field and heat the stratosphere. Even more interesting is what a different height of the stratopause will affect weather/climate. And the location of the lowest level of the stratosphere. That is where is the earths magnetic poles are located. Where will the stratosphere low be, and how will that effect climate? What will a high level stratopause mean in the poles? Probably colder air and a by that higher pressure at ground level. That mean colder winters and larger possibility for a strong polar vortex. And the location? A hint: when the last glacial ended was the magnetic pole just north of Iceland. In the north Atlantic. IF there where strong solar activity with the stratosphere low over open water would that probably generate a very strong, North Atlantic oscillation. A super NAO efficient enough to melt the icecap in Europe. Some intresting links: www.columbia.edu/~lmp/paps/charlton+polvani-JCLIM-2007.pdf
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