349, Martin Vermeer: But all this is uninteresting… it’s like asking how much of your earnings came in as banknotes and how much as coins, and which denominations. The interesting thing is the sum total, right?
As to monetary income, it might make a difference to somebody if your money came in bundles of $100 bills, and if some of your money came in bundles of lower denominations. So it’s a bad analogy.
I have excellent texts on thermodynamics, but they do not address the question I asked. “radiate” vs. “re-radiate”, ok if you insist; collisions with molecules that have a distribution of energies, ok again, though presumably the energized GHG molecules do not warm the N2 and O2 molecules that have even higher energies. The question (reframed as you wish) is a question about how complete and detailed is the knowledge about heat flows. With the earth spinning on its axis and revolving around the sun, and with the consequent rising and falling of temperature and with local transients like winds, clouds, hailstorms and dust devils, local thermodynamic equilibrium is seldom present.
Are there plans to upgrade the RC wiki? The export functionality in recent releases has been greatly improved. Are there recommendations of “must have” RC wiki entries?
There are certain wikis which could be greatly improved. The project is still in the making so expect more updates within the next days/weeks.
Bottom line, im not aware of any other wiki which focus on climate science and quality. The original Wikipedia i consider medium “ok” with many articles lacking a lot. Feedback is welcome.
Pete Dunkelbergsays
SM @ 351“With the earth spinning on its axis and revolving around the sun, and with the consequent rising and falling of temperature and with local transients like winds, clouds, hailstorms and dust devils, local thermodynamic equilibrium is seldom present.”
Non sequitur. How is it possible for snowflakes to grow symmetrically? What is the scale of the molecular interactions you were asking about? And why are you disturbing me at this time of night? Or are you on the late coast?
Septic Matthewsays
352, Hank Roberts: Why would you presume not?
There can’t be a net energy flow from a low energy source to a high energy source. If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.
The relevance of your example requires the existence of another heat source already heating the O2 and N2 molecules (advection from the earth surface, perhaps.) In that case, it is the other heat source that makes the O2 and N2 molecules more energetic, not their collisions with lower energy CO2 molecules.
I am guessing that you do not know the answer, or a citation for the answer, to the question that I asked.
“when GHG molecules absorb radiant energy, they transmit this energy elsewhere via two mechanisms: (a) they re-radiate it at their absorption/emission wavelengths; (b) they collide with lower energy molecules.
What is the fraction, in the atmosphere, of the energy transmitted via each mechanism and how does that fraction vary across altitude, latitude, and pressure?”
I seem to recall that at NTP CO2 rotationally excited states have radiative lifetimes far larger than collisional lifetime. I would expect that collisional lifetimes become longer than radiative lifetimes at just about the upper radiative ‘surface’ of the atmosphere…but i am probably rong in detail, if not in large…
sidd
siddsays
In further reply to Mr. Sceptic Matthew, re radiative/collisional lifetime: I erred by implication at least once in my previous: I believe CO2 is vibrationally excited by IR and rotationally by microwave. But i still think that at NTP the vibrational state also has far higher radiative lifetime than collisional lifetime at NTP in earth atmosphere. so a typical IR excited CO2 molecule at sea level ought to decay by collision far quicker than by radiative emission.
please, corrections are welcome.
sidd
Martin Vermeersays
I have excellent texts on thermodynamics, but they do not address the question I asked.
There’s a reason for that ;-)
You may want to peruse astrophysics texts, where you find LTE violating regimes where this becomes meaningful.
With the earth spinning on its axis and revolving around the sun, and with the consequent rising and falling of temperature and with local transients like winds, clouds, hailstorms and dust devils, local thermodynamic equilibrium is seldom present.
Oh really? You may want to read those “excellent texts”, they do no good just sitting on your shelf… LTE has a very specific meaning.
Edward Greischsays
Rick Perry’s statements are a joke without explanation for most of us. They should be jokes for all of us. Since everybody should know that Rick Perry’s statements are wrong, NPR can get away with playing straight man. NPR is only guilty of putting a joke on the news. Makes you wonder why he didn’t wait until April First to say that.
The public schools are guilty of not teaching enough science so that everybody would get the joke instantly.
Martin Vermeersays
There can’t be a net energy flow from a low energy source to a high energy source. If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.
On the molecular level, simply not true. Think about it.
It may be an obvious–or naive?–point, but at the bulk level, the radiative forcing is constantly raising the energy level of the GHGs but not the O2 and N2. Since everything else we can think of affects all species pretty much equally, you’d think there would be a sort of ‘energy gradient’ established thereby. . .
“… the definition of kinetic temperature … involves just the translational degrees of freedom, but it fails to predict the specific heats of polyatomic gases because the increase in internal energy associated with heating such gases adds energy to rotational and perhaps vibrational degrees of freedom.
Doug Bostromsays
More data is in on Governor Perry.
Q: What makes Rick Perry’s approach to politics different from that of other candidates?
Mr. Issenberg: No candidate has ever presided over a political operation so skeptical about the effectiveness of basic campaign tools and so committed to using social-science methods to rigorously test them.
As the 2006 election season approached, the governor’s top strategist, Dave Carney, invited four political scientists into Perry’s war room and asked them to impose experimental controls on any aspect of the campaign budget that they could randomize and measure. Over the course of that year, the eggheads, as they were known within the campaign, ran experiments testing the effectiveness of all the things that political consultants do reflexively and we take for granted: candidate appearances, TV ads, robocalls, direct mail. These were basically the political world’s version of randomized drug trials, which had been used by academics but never from within a large-scale partisan campaign.
…
The eggheads controlled Perry’s schedule for three days and randomly assigned his travel across Texas. During that time, they conducted a massive volume of polling calls — large enough to discern significant movement in each city — and tracked contributions and volunteer activity. They found that Perry’s presence in a city had an impact: his approval ratings went up, and contributions and volunteer signups increased after he did a public event.
Because they had randomized the schedule, the eggheads were able with confidence to attribute the changes to Perry’s presence. It wasn’t a novel conclusion — candidates have been doing whistle-stop tours and rallies and visits to businesses forever under the impression that they would be helped locally — but no one ever had the tools to isolate the effect of the visit on these different variables.
Now this article does not say if Perry was aware of these activities. If not, the question of whether he actually believes the things he says about the scientific community is still open. On the other hand, if Perry was working directly with Carney on these social science experiments, this suggests that Perry’s remarks on science are expedient, tuned to his audience, behavior that in some circumstances would be termed “lying.”
As to the application of Perry’s social science findings, I thought that conservatives loathed “social engiineering.” Yet here we see forces and processes applied to raw human material– based on scientifically derived predictions– in order to shape that human material (electoral ore) into something useful to Governor Perry. Sounds like engineers at work.
Pete Dunkelbergsays
ummm sundry comments getting fuzzy (not including Martin).
Longwave radiation excites GHG molecule, then the energy quickly spreads to other molecules, mostly diatomic. Every so often (on the molecular time scale, ie many times per second) a GHG molecule gets kicked to a high energy state (perhaps stepwise, perhaps all at once) and stays there long enough to radiate. So any increase in thermal radiation is constantly heating all the gas.
In case there is any book that would help orient better questions it is raypierre’s.
Doug Bostromsays
One other thought about Perry’s social science experiments occurs to me.
In an academic setting Perry’s researchers would likely have been required to put this experiment in front of an IRB, for a dispassionate review of the experiment’s ethics and the impacts of the experiment on the human subjects involved. Informed consent on the part of the subjects would also likely be required. It’s not probable that such procedures were followed in the case of the experimental subjects touched by Carney’s investigation.
So here we have whole towns and cities full of human subjects, enlisted in a grand social science experiment without their knowledge or consent. I’m left wondering what would happen if this sort of practice was uncovered at NSF’s Directorate for Social, Behavioral & Economic Sciences.
The style of freelance, methodical, goal-oriented, morally dubious activity of the sort Perry is practicing is often termed “hacking” of the black hat variety. Perry’s campaign is to harvest ballots from voters, obtain something of value, and here we see methods employed for that purpose which seem to include a form of deception. Hacking the electorate is not new, but Perry seems to be ahead of the rest of the pack.
Marcussays
Septic matthew:
There can’t be a net energy flow from a low energy source to a high energy source. If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.
No. Consider a billard ball on x=0, and a second ball with identical mass approaching it with velocity vx along the x axis. The second ball will come to rest and exchange all momentum to the first one.
Now repeat the thought experiment with the first ball going through the origin at collision time still at rest resp. X axis, but with arbitrary velocity resp. Y axis vy. Set vy > vx, arbitrarily.
At the collision event energy is transferred from the ball with lower energy to that with higher energy, both energy and momentum of the system conserved.
The entropy law and the whole of thermodynamics accounts for *ensembles*, not singular particles
Cheers, Marcus
Septic Matthewsays
365, Pete Dunkelburg: So any increase in thermal radiation is constantly heating all the gas.
That is beyond dispute, or at least I think it is beyond dispute.
For a mole of CO2 (or other GHG) molecules in a well-defined region, say in a rectangular horizontal layer with a side of 1 square meter, how much of the absorbed radiant energy is transferred to the N2 and O2 molecules via collisions, and how much is radiated? Is the answer the same for a mole of CO2 molecules in a 1 meter tall cylinder? How about for the CO2 molecules in a really thin layer (which might be made arbitrarily thin in a limit)?
361, Martin Vermeer: Ehm, you don’t heat molecules, you heat gas.
363, Hank Roberts: It’s true, I have no answer or citation for the question you asked. The question you asked can be improved, but not answered as asked.
t_p_hamiltonsays
Septic Matthew needs to KISS:”If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.”
If this was true, then a gas at equilibrium would have all molecules going the same velocity. Contrast this with the Maxwell-Boltzmann distribution.
Pete Dunkelbergsays
Pretty much all transferred and pretty much all radiated. Over and over.
How important is the findings of this study? If the results of hold up under wider scientific scrutiny, what are the implications for anthropogenic global warming?
I re-read the posts on RealClimate on the Atlantic circulation and I recently read Peter Ward’s “Under a Green Sky” where he writes that in some of the past mass extinctions changes in ocean circulation was a key factor.
I was wondering what is the up-to-date state of knowledge of ocean circulation and AGW is, particularly in the Atlantic. Maybe a new post from RealClimate can be written or someone can direct me to a recent review paper on the topic.
Joseph O’Sullivan @ 371, That’s a neat paper. Ocean currents are important redistributors of heat. Learning about currents like that one and this one will help us to have sharper models in a couple years. As you say it would be nice to have an up to date review of ocean circulation, yet as these papers show, up to date is hard to get except by reading new research all the time. Meanwhile global warming will continue.
Pete Dunkelbergsays
David Benson, in a perfect world … yes and at least a few people are working on it.
SM, you started from mistaken assumptions; you haven’t said where you got those.
What do you know about the wavelengths and intensity of the incoming radiation; material of the container; temperatures; time span; gases; pressure; mean free path for photons involved; time between collisions. Just handwaving from my amateur reading, which leads me to think you’re missing some information needed to ask a meaningful question.
What are you reading? Name your reference shelf books, the ones you said are right there next to you, eh?
For those following along who like me are just amateurs trying to figure out what people are talking about, these are useful:
“…this suggests that Perry’s remarks on science are expedient…”
That’s politics. Part manipulation, part pandering. Part representing, part testifying. Part art, part science. You can be sure that a lot of effort goes into crafting the message, polishing the performance and, well, gaming the system–just as you’d expect designers to fuss over logos, lawyers to hone their arguments, copywriters to sell the brand, and good old boys to crunch the numbers and gerrymander their districts.
What does Perry really think about science? Does it matter? Any way you look at it he’s full of baloney.
Ray Ladburysays
Septic Matthew,
There is a reason why statistical mechanics (and the atmospheric science you are trying to understand, which is based on stat mech) deals with numbers of particles that are–to use a technical term–freakin’ huge. Huge numbers simplify things tremendously. Rather than talking about energy transfer between A CO2 molecule and A O2 molecule, you are looking at net transfer between many, many of said molecules–it is the average that matters. If you have CO2 and O2 starting out at the same temperature, and CO2 molecules absorb a bunch of IR, then the CO2 molecules will be shifted to higher energy than the equilibrium distribution associated with that temperature. By equipartition they will shed some of that extra energy in collisions with other molecules and transfer some of the energy to O2 and N2 molecules. Equipartition is a strong tool for figuring out which way energy will flow.
John Wsays
OH NO! I find myself in agreement with Ray Ladbury @ 378.
Although, I would note that unlike the CO2 molecules being able to absorb, store, emit energy with extra-translational motion (without affecting temperature); the O2 and N2 molecules that through collision receive energy from potentially IR excited CO2 molecules must do so through translational motion (by temperature increase). Also, those collisions can also transfer translational energy from O2 and N2 to CO2 molecules that could lose this energy by emitting IR thus having a local cooling effect.
375, Hank Roberts: incoming radiation; material of the container; temperatures; time span; gases; pressure;
I was referring to the atmosphere of earth, and I asked about effects of altitude and pressure. I selected CO2, N2 and O2 as some constituents: CO2 because it is the focus of discussion of AGW; N2 and O2 because they are the most prevalent of the gases in the atmosphere. The answer isn’t necessarily the same for the CO2 and H2O in a region just above the earth’s surface at local temperature and pressure, or in every geographic region.
You might just as well admit that you neither know nor care what the answer is.
Edward Greischsays
364 Doug Bostrom: “experiments testing the effectiveness of all the things that political consultants do reflexively”
That actually makes sense out of Rick Perry’s getting elementary school science wrong. Like the other Republican candidates, he was gesturing hypnotically to the religious right. See Altemeyer’s book. “The Authoritarians” by Bob Altemeyer. Free download from: http://home.cc.umanitoba.ca/~altemey/
One Anonymous Blokesays
Septic Matthew #380 you have been advised that your question is essentially meaningless. How much time have you devoted to understanding why anyone would know or care about the answer to a meaningless question? I think you need to read Ray Ladbury’s response at #378, and then think about it. “We need better septics.”
Craig Nazorsays
Having lived in Texas for a number of years, and having watched Governor Perry up close and personal for that time, here is what I think about his attitude on anthropogenic global warming:
He doesn’t really care if it is happening or not, because he doesn’t feel that it is likely that humans can (or will) do anything about it. It really doesn’t matter to him if humans are responsible, or that they could do something about it if they tried. Action to address AGW is just not likely to happen, and he is fine with this – in fact, he doesn’t really see this as any of his responsibility. It is simply beyond his control.
But as a tactic to win an election, he sees denying AGW as an excellent way to appeal to those whose support he needs. IT IS A TACTIC, nothing more and nothing less. And if public opinion changed so that it would benefit him to acknowledge AGW and even support political action to address it, he would suddenly find a way to “change his mind,” just like he did to overcome his strong denials that he would never run for president.
In other words, to Rick Perry, it is first and foremost about winning. It is not about changing society for the better, except at the margins (that is, after he has done what he needed to do to win).
That is apparently what he sees as “leadership” – you have to “win” to “lead.” Truth, or justice, or integrity all become a distant second to WINNING.
I have watched Perry for a long time on this and other issues, and that is the pattern that emerges. And remember – HE NAS NEVER LOST AN ELECTION.
If that doesn’t scare you, I don’t know what will.
Marcussays
I would not be harsh on SM because he wants to dig his way to understanding through “microphysics”, because I would regard this a decent approach in principle even if not *necessary*. Though I am not sure what he is about with the consideration of the volume element geometry.
One maybe could consider a back of the envelope calculation to achieve orders of magnitude, for a column element at high altitude that is cold and has low pressure. One could pick some wavelengths/state transitions of interest, work out their average lifetime from lifetime broadening or look them up, and compare those to collision frequency. The latter could be worked out from kinetic gas theory quite simply.
Would You be happy with that, Septical Matthew?
I would recon that everywhere where line broadening is dominated by pressure, energy transfer by collision overpowers spontaneous re-radiation, almost per definition.
Cheers,
Marcus
Martin Vermeersays
I would not be harsh on SM because he wants to dig his way to understanding through “microphysics”, because I would regard this a decent approach in principle even if not *necessary*.
Yeah, sure… actually what he wants is not impossible, and should just be done as you outline. Collision frequency follows directly from mean free path (tabulated here) and temperature –) mean velocity by kT = mv^2.
Excitation state lifetimes are harder to come by; is this relevant?
“The important lifetimes in the CO2 laser are practically all determined by collisional phenomena. The radiative lifetimes vary from a few milliseconds to a few seconds, whereas the mean free time between molecular collision is of the order 10 to 100 nanoseconds.”
And as you say, the shape of the air element just doesn’t enter into it.
Martin Vermeersays
I would recon that everywhere where line broadening is dominated by pressure, energy transfer by collision overpowers spontaneous re-radiation, almost per definition.
Marcus that’s another way of saying “LTE”…
Septic Matthewsays
384, Marcus: One maybe could consider a back of the envelope calculation to achieve orders of magnitude, for a column element at high altitude that is cold and has low pressure. One could pick some wavelengths/state transitions of interest, work out their average lifetime from lifetime broadening or look them up, and compare those to collision frequency. The latter could be worked out from kinetic gas theory quite simply.
That would be a good start. Then I’d hope for some confirming/testing experiments. Then differences between low, medium and high altitudes, and over water vs. over land of different types such as desert and forest. At the highest level of the atmosphere the atmosphere is sparse, as we all know, and all energy transmitted out to space is via radiation.
378, Ray Ladbury: numbers of particles that are–to use a technical term–freakin’ huge.
That’s why in one of my formulations of the question I proposed a volume, of different shapes, containing a mole of GHG molecules: say a region containing at least 1 mole each of CO2, H2O and CH4, which would have many times more moles of O2 and N2.
Septic Matthewsays
385, Martin Vermeer: Excitation state lifetimes are harder to come by; is this relevant?
“The important lifetimes in the CO2 laser are practically all determined by collisional phenomena. The radiative lifetimes vary from a few milliseconds to a few seconds, whereas the mean free time between molecular collision is of the order 10 to 100 nanoseconds.”
So collisions dominate at low altitudes and are rare at high altitudes. What’s the variation in between?
For a large volume of air, say 125 cubic miles, it matters whether the region is nearly flat near the ocean surface, or a narrow column above a rain forest.
Have I mentioned that I am a statistician? Statistics is about variation, especially about modeling deterministic variation in the presence of random variation. I think that quantitative answers to my question have deterministic (altitude above a small part of the Pacific Ocean) and random (across parts of the Pacific Ocean) components.
Septic Matthewsays
We should eagerly anticipate the publications that result from this voyage:
Big deal. “Doing the maths without doing the physics is not doing the physics.” You should’ve listened to Wegman.
deconvolutersays
RE: #308 (the link therein)
Nice graphic, but I think that it may be the second source mentioned in this particular thread, which seriously over-simplifies the action of clouds i.e. that they necessarily create a negative feedback.
deconvolutersays
RE: #390
Wegman.
When it comes to statistical physics (SP), I doubt whether a typical statistician would be familiar with much of the statistics,let alone the maths or the physics, and of course some of the problems discussed above have been concerned with SP.
Australian PR firm Jackson Wells handles publicity not only for Cambridge University Press and the University of West Sydney but also Australia’s anti-science “Galileo Movement.”
Jackson Wells is in position of conflicted interest. To the extent Galileo Movement succeeds, Cambridge University Press and UWS fail:
Humans did not cause global warming. It’s part of Nature’s ongoing changing of climate. Climate alarm though, is caused by humans – academics spreading falsehoods and even lies and grabbing Government grants, politicians telling lies and using fear and guilt to push taxation and regulations. Unlike human production of carbon dioxide though which has many benefits, these moral issues are entirely destructive.
Generation of reliable data about the impacts of climate change on Australia’s land, water and alternative energy sources is crucial for our economy, environment and society.
The Climate Change and Energy Research (CCER) facility will provide empirical data to assess the impact of climate change on Australia’s land and water resources and assist the nation to adapt to a carbon-constrained economy.
The CCER facility will establish Australia’s most comprehensive climate change research projects.
Re my coauthored book on sea level rise, the manuscript must be in the hands of the publisher by the summer of 2012, i.e., long before the next IPCC assessment report will be available.
My guess is that the IPCC report will not contain any brand-new or block-busting information on sea level rise, but will essentially be a restatement and a summation of the current state of knowledge on this subject.
If I’m mistaken in this belief, please let me know. Thanks very much.
deconvolutersays
Re : #394
CUP?
Raypierre’s book, and many others, excellent.
Lomborg’s book(s). If they employed reviewers, they chose ones who didn’t do their job properly, especially for the chapter consisting of a review of climate science in the first book.
ozajhsays
Is my untutored eye missing something, or does the Cryosphere Today graphic show the Main NorthWest Passage completely open?
[Response: If you mean Lacanster Sound/Viscount Melville Sound, then yes. This is not however the ‘Main Northwest Passage’ – traditionally the NWP was always the southern route through the McLintock Channel and south of Victoria Island. This full passage opened up around the same time in Aug 2007 and Aug 2010. – gavin]
“There is increasing concern about the potential instability of both the Greenland and the West Antarctic Ice Sheets leading to a more rapid rate of sea-level rise than the current model projections. While our understanding of the relevant processes is limited, it is important to recognize that the uncertainties are essentially one-sided: the processes can only lead to
a higher rate of sea-level rise than current model projections ….”
Hunt Janin, your work in never done.
http://www.nature.com/ngeo/focus/warm-ice-sheets/index.html
349, Martin Vermeer: But all this is uninteresting… it’s like asking how much of your earnings came in as banknotes and how much as coins, and which denominations. The interesting thing is the sum total, right?
As to monetary income, it might make a difference to somebody if your money came in bundles of $100 bills, and if some of your money came in bundles of lower denominations. So it’s a bad analogy.
I have excellent texts on thermodynamics, but they do not address the question I asked. “radiate” vs. “re-radiate”, ok if you insist; collisions with molecules that have a distribution of energies, ok again, though presumably the energized GHG molecules do not warm the N2 and O2 molecules that have even higher energies. The question (reframed as you wish) is a question about how complete and detailed is the knowledge about heat flows. With the earth spinning on its axis and revolving around the sun, and with the consequent rising and falling of temperature and with local transients like winds, clouds, hailstorms and dust devils, local thermodynamic equilibrium is seldom present.
> presumably the energized GHG molecules do not warm the
> N2 and O2 molecules that have even higher energies.
Why would you presume not?
http://www.drroyspencer.com/2010/07/yes-virginia-cooler-objects-can-make-warmer-objects-even-warmer-still/
Are there plans to upgrade the RC wiki? The export functionality in recent releases has been greatly improved. Are there recommendations of “must have” RC wiki entries?
So far the Climate Progress wiki contains over 500 content pages! :)
http://climateprogress.net
There are certain wikis which could be greatly improved. The project is still in the making so expect more updates within the next days/weeks.
Bottom line, im not aware of any other wiki which focus on climate science and quality. The original Wikipedia i consider medium “ok” with many articles lacking a lot. Feedback is welcome.
SM @ 351“With the earth spinning on its axis and revolving around the sun, and with the consequent rising and falling of temperature and with local transients like winds, clouds, hailstorms and dust devils, local thermodynamic equilibrium is seldom present.”
Non sequitur. How is it possible for snowflakes to grow symmetrically? What is the scale of the molecular interactions you were asking about? And why are you disturbing me at this time of night? Or are you on the late coast?
352, Hank Roberts: Why would you presume not?
There can’t be a net energy flow from a low energy source to a high energy source. If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.
The relevance of your example requires the existence of another heat source already heating the O2 and N2 molecules (advection from the earth surface, perhaps.) In that case, it is the other heat source that makes the O2 and N2 molecules more energetic, not their collisions with lower energy CO2 molecules.
I am guessing that you do not know the answer, or a citation for the answer, to the question that I asked.
Arctic Sea Ice Prediction Update:
http://aperfectstormcometh.blogspot.com/2011/08/current-state-of-arctic-sea-ice-arctic_22.html
Mr. Sceptic Matthew asks:
“when GHG molecules absorb radiant energy, they transmit this energy elsewhere via two mechanisms: (a) they re-radiate it at their absorption/emission wavelengths; (b) they collide with lower energy molecules.
What is the fraction, in the atmosphere, of the energy transmitted via each mechanism and how does that fraction vary across altitude, latitude, and pressure?”
I seem to recall that at NTP CO2 rotationally excited states have radiative lifetimes far larger than collisional lifetime. I would expect that collisional lifetimes become longer than radiative lifetimes at just about the upper radiative ‘surface’ of the atmosphere…but i am probably rong in detail, if not in large…
sidd
In further reply to Mr. Sceptic Matthew, re radiative/collisional lifetime: I erred by implication at least once in my previous: I believe CO2 is vibrationally excited by IR and rotationally by microwave. But i still think that at NTP the vibrational state also has far higher radiative lifetime than collisional lifetime at NTP in earth atmosphere. so a typical IR excited CO2 molecule at sea level ought to decay by collision far quicker than by radiative emission.
please, corrections are welcome.
sidd
There’s a reason for that ;-)
You may want to peruse astrophysics texts, where you find LTE violating regimes where this becomes meaningful.
Oh really? You may want to read those “excellent texts”, they do no good just sitting on your shelf… LTE has a very specific meaning.
Rick Perry’s statements are a joke without explanation for most of us. They should be jokes for all of us. Since everybody should know that Rick Perry’s statements are wrong, NPR can get away with playing straight man. NPR is only guilty of putting a joke on the news. Makes you wonder why he didn’t wait until April First to say that.
The public schools are guilty of not teaching enough science so that everybody would get the joke instantly.
On the molecular level, simply not true. Think about it.
Ehm, you don’t heat molecules, you heat gas.
SM, numerous comments–
It may be an obvious–or naive?–point, but at the bulk level, the radiative forcing is constantly raising the energy level of the GHGs but not the O2 and N2. Since everything else we can think of affects all species pretty much equally, you’d think there would be a sort of ‘energy gradient’ established thereby. . .
> I am guessing that you do not know the answer, or a citation
> for the answer, to the question that I asked.
It’s true, I have no answer or citation for the question you asked.
The question you asked can be improved, but not answered as asked.
SM, you could name the books on your shelf — then others who have them can talk about why you aren’t finding the answers to your question in them.
Or perhaps the hyperphysics site might be helpful as a common/shared source?
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/eqpar.html
“… the definition of kinetic temperature … involves just the translational degrees of freedom, but it fails to predict the specific heats of polyatomic gases because the increase in internal energy associated with heating such gases adds energy to rotational and perhaps vibrational degrees of freedom.
More data is in on Governor Perry.
Q: What makes Rick Perry’s approach to politics different from that of other candidates?
Mr. Issenberg: No candidate has ever presided over a political operation so skeptical about the effectiveness of basic campaign tools and so committed to using social-science methods to rigorously test them.
As the 2006 election season approached, the governor’s top strategist, Dave Carney, invited four political scientists into Perry’s war room and asked them to impose experimental controls on any aspect of the campaign budget that they could randomize and measure. Over the course of that year, the eggheads, as they were known within the campaign, ran experiments testing the effectiveness of all the things that political consultants do reflexively and we take for granted: candidate appearances, TV ads, robocalls, direct mail. These were basically the political world’s version of randomized drug trials, which had been used by academics but never from within a large-scale partisan campaign.
…
The eggheads controlled Perry’s schedule for three days and randomly assigned his travel across Texas. During that time, they conducted a massive volume of polling calls — large enough to discern significant movement in each city — and tracked contributions and volunteer activity. They found that Perry’s presence in a city had an impact: his approval ratings went up, and contributions and volunteer signups increased after he did a public event.
Because they had randomized the schedule, the eggheads were able with confidence to attribute the changes to Perry’s presence. It wasn’t a novel conclusion — candidates have been doing whistle-stop tours and rallies and visits to businesses forever under the impression that they would be helped locally — but no one ever had the tools to isolate the effect of the visit on these different variables.
http://thecaucus.blogs.nytimes.com/2011/08/22/rick-perrys-scientific-campaign-method/?hp
Now this article does not say if Perry was aware of these activities. If not, the question of whether he actually believes the things he says about the scientific community is still open. On the other hand, if Perry was working directly with Carney on these social science experiments, this suggests that Perry’s remarks on science are expedient, tuned to his audience, behavior that in some circumstances would be termed “lying.”
As to the application of Perry’s social science findings, I thought that conservatives loathed “social engiineering.” Yet here we see forces and processes applied to raw human material– based on scientifically derived predictions– in order to shape that human material (electoral ore) into something useful to Governor Perry. Sounds like engineers at work.
ummm sundry comments getting fuzzy (not including Martin).
Longwave radiation excites GHG molecule, then the energy quickly spreads to other molecules, mostly diatomic. Every so often (on the molecular time scale, ie many times per second) a GHG molecule gets kicked to a high energy state (perhaps stepwise, perhaps all at once) and stays there long enough to radiate. So any increase in thermal radiation is constantly heating all the gas.
In case there is any book that would help orient better questions it is raypierre’s.
One other thought about Perry’s social science experiments occurs to me.
In an academic setting Perry’s researchers would likely have been required to put this experiment in front of an IRB, for a dispassionate review of the experiment’s ethics and the impacts of the experiment on the human subjects involved. Informed consent on the part of the subjects would also likely be required. It’s not probable that such procedures were followed in the case of the experimental subjects touched by Carney’s investigation.
So here we have whole towns and cities full of human subjects, enlisted in a grand social science experiment without their knowledge or consent. I’m left wondering what would happen if this sort of practice was uncovered at NSF’s Directorate for Social, Behavioral & Economic Sciences.
The style of freelance, methodical, goal-oriented, morally dubious activity of the sort Perry is practicing is often termed “hacking” of the black hat variety. Perry’s campaign is to harvest ballots from voters, obtain something of value, and here we see methods employed for that purpose which seem to include a form of deception. Hacking the electorate is not new, but Perry seems to be ahead of the rest of the pack.
Septic matthew:
There can’t be a net energy flow from a low energy source to a high energy source. If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.
No. Consider a billard ball on x=0, and a second ball with identical mass approaching it with velocity vx along the x axis. The second ball will come to rest and exchange all momentum to the first one.
Now repeat the thought experiment with the first ball going through the origin at collision time still at rest resp. X axis, but with arbitrary velocity resp. Y axis vy. Set vy > vx, arbitrarily.
At the collision event energy is transferred from the ball with lower energy to that with higher energy, both energy and momentum of the system conserved.
The entropy law and the whole of thermodynamics accounts for *ensembles*, not singular particles
Cheers, Marcus
365, Pete Dunkelburg: So any increase in thermal radiation is constantly heating all the gas.
That is beyond dispute, or at least I think it is beyond dispute.
For a mole of CO2 (or other GHG) molecules in a well-defined region, say in a rectangular horizontal layer with a side of 1 square meter, how much of the absorbed radiant energy is transferred to the N2 and O2 molecules via collisions, and how much is radiated? Is the answer the same for a mole of CO2 molecules in a 1 meter tall cylinder? How about for the CO2 molecules in a really thin layer (which might be made arbitrarily thin in a limit)?
361, Martin Vermeer: Ehm, you don’t heat molecules, you heat gas.
363, Hank Roberts: It’s true, I have no answer or citation for the question you asked. The question you asked can be improved, but not answered as asked.
Septic Matthew needs to KISS:”If the CO2 molecule has a lower energy than the O2 molecule with which it collides , then any net energy transfer is from the O2 to the CO2 molecule.”
If this was true, then a gas at equilibrium would have all molecules going the same velocity. Contrast this with the Maxwell-Boltzmann distribution.
Pretty much all transferred and pretty much all radiated. Over and over.
I recently read this news release from Woods Hole Oceanographic Institute:
“News Release : Newly Discovered Icelandic Current Could Change North Atlantic Climate Picture”
http://www.whoi.edu/page.do?pid=7545&tid=282&cid=110069&ct=162
The paper is in Nature Geoscience:
“Significant role of the North Icelandic Jet in the formation of Denmark Strait overflow water”
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1234.html
How important is the findings of this study? If the results of hold up under wider scientific scrutiny, what are the implications for anthropogenic global warming?
I re-read the posts on RealClimate on the Atlantic circulation and I recently read Peter Ward’s “Under a Green Sky” where he writes that in some of the past mass extinctions changes in ocean circulation was a key factor.
I was wondering what is the up-to-date state of knowledge of ocean circulation and AGW is, particularly in the Atlantic. Maybe a new post from RealClimate can be written or someone can direct me to a recent review paper on the topic.
An a more ideal world, this would be off-topic:
http://thinkprogress.org/romm/2011/08/22/300821/nsf-inspector-general-investigation-michael-mann/
but I do hope this brings these unpleasant (to say the least) episodes to an end.
Joseph O’Sullivan @ 371, That’s a neat paper. Ocean currents are important redistributors of heat. Learning about currents like that one and this one will help us to have sharper models in a couple years. As you say it would be nice to have an up to date review of ocean circulation, yet as these papers show, up to date is hard to get except by reading new research all the time. Meanwhile global warming will continue.
David Benson, in a perfect world … yes and at least a few people are working on it.
SM, you started from mistaken assumptions; you haven’t said where you got those.
What do you know about the wavelengths and intensity of the incoming radiation; material of the container; temperatures; time span; gases; pressure; mean free path for photons involved; time between collisions. Just handwaving from my amateur reading, which leads me to think you’re missing some information needed to ask a meaningful question.
What are you reading? Name your reference shelf books, the ones you said are right there next to you, eh?
For those following along who like me are just amateurs trying to figure out what people are talking about, these are useful:
U4735 – Lecture 4. Greenhouse Effect
http://www.ldeo.columbia.edu/edu/dees/U4735/lectures/20/
How is energy transferred from radiant energy to matter …
http://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf
Infrared radiation and planetary temperature
john burgeson — Even shorter is “Why does climate change? Causes and Timescales” by Chris Colose
http://blog.timesunion.com/weather/why-does-climate-change-causes-and-timescales/1261/
Doug Bostrom @364
That’s politics. Part manipulation, part pandering. Part representing, part testifying. Part art, part science. You can be sure that a lot of effort goes into crafting the message, polishing the performance and, well, gaming the system–just as you’d expect designers to fuss over logos, lawyers to hone their arguments, copywriters to sell the brand, and good old boys to crunch the numbers and gerrymander their districts.
What does Perry really think about science? Does it matter? Any way you look at it he’s full of baloney.
Septic Matthew,
There is a reason why statistical mechanics (and the atmospheric science you are trying to understand, which is based on stat mech) deals with numbers of particles that are–to use a technical term–freakin’ huge. Huge numbers simplify things tremendously. Rather than talking about energy transfer between A CO2 molecule and A O2 molecule, you are looking at net transfer between many, many of said molecules–it is the average that matters. If you have CO2 and O2 starting out at the same temperature, and CO2 molecules absorb a bunch of IR, then the CO2 molecules will be shifted to higher energy than the equilibrium distribution associated with that temperature. By equipartition they will shed some of that extra energy in collisions with other molecules and transfer some of the energy to O2 and N2 molecules. Equipartition is a strong tool for figuring out which way energy will flow.
OH NO! I find myself in agreement with Ray Ladbury @ 378.
Although, I would note that unlike the CO2 molecules being able to absorb, store, emit energy with extra-translational motion (without affecting temperature); the O2 and N2 molecules that through collision receive energy from potentially IR excited CO2 molecules must do so through translational motion (by temperature increase). Also, those collisions can also transfer translational energy from O2 and N2 to CO2 molecules that could lose this energy by emitting IR thus having a local cooling effect.
Equipartition Theorem
375, Hank Roberts: incoming radiation; material of the container; temperatures; time span; gases; pressure;
I was referring to the atmosphere of earth, and I asked about effects of altitude and pressure. I selected CO2, N2 and O2 as some constituents: CO2 because it is the focus of discussion of AGW; N2 and O2 because they are the most prevalent of the gases in the atmosphere. The answer isn’t necessarily the same for the CO2 and H2O in a region just above the earth’s surface at local temperature and pressure, or in every geographic region.
You might just as well admit that you neither know nor care what the answer is.
364 Doug Bostrom: “experiments testing the effectiveness of all the things that political consultants do reflexively”
That actually makes sense out of Rick Perry’s getting elementary school science wrong. Like the other Republican candidates, he was gesturing hypnotically to the religious right. See Altemeyer’s book. “The Authoritarians” by Bob Altemeyer. Free download from:
http://home.cc.umanitoba.ca/~altemey/
Septic Matthew #380 you have been advised that your question is essentially meaningless. How much time have you devoted to understanding why anyone would know or care about the answer to a meaningless question? I think you need to read Ray Ladbury’s response at #378, and then think about it. “We need better septics.”
Having lived in Texas for a number of years, and having watched Governor Perry up close and personal for that time, here is what I think about his attitude on anthropogenic global warming:
He doesn’t really care if it is happening or not, because he doesn’t feel that it is likely that humans can (or will) do anything about it. It really doesn’t matter to him if humans are responsible, or that they could do something about it if they tried. Action to address AGW is just not likely to happen, and he is fine with this – in fact, he doesn’t really see this as any of his responsibility. It is simply beyond his control.
But as a tactic to win an election, he sees denying AGW as an excellent way to appeal to those whose support he needs. IT IS A TACTIC, nothing more and nothing less. And if public opinion changed so that it would benefit him to acknowledge AGW and even support political action to address it, he would suddenly find a way to “change his mind,” just like he did to overcome his strong denials that he would never run for president.
In other words, to Rick Perry, it is first and foremost about winning. It is not about changing society for the better, except at the margins (that is, after he has done what he needed to do to win).
That is apparently what he sees as “leadership” – you have to “win” to “lead.” Truth, or justice, or integrity all become a distant second to WINNING.
I have watched Perry for a long time on this and other issues, and that is the pattern that emerges. And remember – HE NAS NEVER LOST AN ELECTION.
If that doesn’t scare you, I don’t know what will.
I would not be harsh on SM because he wants to dig his way to understanding through “microphysics”, because I would regard this a decent approach in principle even if not *necessary*. Though I am not sure what he is about with the consideration of the volume element geometry.
One maybe could consider a back of the envelope calculation to achieve orders of magnitude, for a column element at high altitude that is cold and has low pressure. One could pick some wavelengths/state transitions of interest, work out their average lifetime from lifetime broadening or look them up, and compare those to collision frequency. The latter could be worked out from kinetic gas theory quite simply.
Would You be happy with that, Septical Matthew?
I would recon that everywhere where line broadening is dominated by pressure, energy transfer by collision overpowers spontaneous re-radiation, almost per definition.
Cheers,
Marcus
Yeah, sure… actually what he wants is not impossible, and should just be done as you outline. Collision frequency follows directly from mean free path (tabulated here) and temperature –) mean velocity by kT = mv^2.
Excitation state lifetimes are harder to come by; is this relevant?
“The important lifetimes in the CO2 laser are practically all determined by collisional phenomena. The radiative lifetimes vary from a few milliseconds to a few seconds, whereas the mean free time between molecular collision is of the order 10 to 100 nanoseconds.”
And as you say, the shape of the air element just doesn’t enter into it.
Marcus that’s another way of saying “LTE”…
384, Marcus: One maybe could consider a back of the envelope calculation to achieve orders of magnitude, for a column element at high altitude that is cold and has low pressure. One could pick some wavelengths/state transitions of interest, work out their average lifetime from lifetime broadening or look them up, and compare those to collision frequency. The latter could be worked out from kinetic gas theory quite simply.
That would be a good start. Then I’d hope for some confirming/testing experiments. Then differences between low, medium and high altitudes, and over water vs. over land of different types such as desert and forest. At the highest level of the atmosphere the atmosphere is sparse, as we all know, and all energy transmitted out to space is via radiation.
378, Ray Ladbury: numbers of particles that are–to use a technical term–freakin’ huge.
That’s why in one of my formulations of the question I proposed a volume, of different shapes, containing a mole of GHG molecules: say a region containing at least 1 mole each of CO2, H2O and CH4, which would have many times more moles of O2 and N2.
385, Martin Vermeer: Excitation state lifetimes are harder to come by; is this relevant?
“The important lifetimes in the CO2 laser are practically all determined by collisional phenomena. The radiative lifetimes vary from a few milliseconds to a few seconds, whereas the mean free time between molecular collision is of the order 10 to 100 nanoseconds.”
So collisions dominate at low altitudes and are rare at high altitudes. What’s the variation in between?
For a large volume of air, say 125 cubic miles, it matters whether the region is nearly flat near the ocean surface, or a narrow column above a rain forest.
Have I mentioned that I am a statistician? Statistics is about variation, especially about modeling deterministic variation in the presence of random variation. I think that quantitative answers to my question have deterministic (altitude above a small part of the Pacific Ocean) and random (across parts of the Pacific Ocean) components.
We should eagerly anticipate the publications that result from this voyage:
http://www.awi.de/en/news/press_releases/detail/item/rv_polarstern_reaches_north_pole/?tx_list_pi1%5Bmode%5D=6&cHash=e4f4e0a501e31c702c3e9f2195b7ceb5
SM — “Have I mentioned that I am a statistician?”
Big deal. “Doing the maths without doing the physics is not doing the physics.” You should’ve listened to Wegman.
RE: #308 (the link therein)
Nice graphic, but I think that it may be the second source mentioned in this particular thread, which seriously over-simplifies the action of clouds i.e. that they necessarily create a negative feedback.
RE: #390
Wegman.
When it comes to statistical physics (SP), I doubt whether a typical statistician would be familiar with much of the statistics,let alone the maths or the physics, and of course some of the problems discussed above have been concerned with SP.
> some confirming/testing experiments.
http://bbs.keyhole.com/ubb/ubbthreads.php?ubb=showflat&Number=1432047
http://laserstars.org/history/co2.gif
“The R(8) transition at 10.33 microns in the infrared is produced from one vibrational quanta of asymmetric stretching to one quantum of symmetric stretching with a change of one quantum of rotational energy from J=8 to J=7”
Australian PR firm Jackson Wells handles publicity not only for Cambridge University Press and the University of West Sydney but also Australia’s anti-science “Galileo Movement.”
Jackson Wells is in position of conflicted interest. To the extent Galileo Movement succeeds, Cambridge University Press and UWS fail:
Galileo Movement:
Humans did not cause global warming. It’s part of Nature’s ongoing changing of climate. Climate alarm though, is caused by humans – academics spreading falsehoods and even lies and grabbing Government grants, politicians telling lies and using fear and guilt to push taxation and regulations. Unlike human production of carbon dioxide though which has many benefits, these moral issues are entirely destructive.
UWS Climate Change and Energy Research Facility:
Generation of reliable data about the impacts of climate change on Australia’s land, water and alternative energy sources is crucial for our economy, environment and society.
The Climate Change and Energy Research (CCER) facility will provide empirical data to assess the impact of climate change on Australia’s land and water resources and assist the nation to adapt to a carbon-constrained economy.
The CCER facility will establish Australia’s most comprehensive climate change research projects.
Cambridge University Press:
Cambridge University Press advances learning, knowledge and research worldwide
Time to drop a dime?
University of West Sydney contact information
Contact information for Cambridge University Press
Re my coauthored book on sea level rise, the manuscript must be in the hands of the publisher by the summer of 2012, i.e., long before the next IPCC assessment report will be available.
My guess is that the IPCC report will not contain any brand-new or block-busting information on sea level rise, but will essentially be a restatement and a summation of the current state of knowledge on this subject.
If I’m mistaken in this belief, please let me know. Thanks very much.
Re : #394
CUP?
Raypierre’s book, and many others, excellent.
Lomborg’s book(s). If they employed reviewers, they chose ones who didn’t do their job properly, especially for the chapter consisting of a review of climate science in the first book.
Is my untutored eye missing something, or does the Cryosphere Today graphic show the Main NorthWest Passage completely open?
[Response: If you mean Lacanster Sound/Viscount Melville Sound, then yes. This is not however the ‘Main Northwest Passage’ – traditionally the NWP was always the southern route through the McLintock Channel and south of Victoria Island. This full passage opened up around the same time in Aug 2007 and Aug 2010. – gavin]
For Hunt Janin: I’m sure you’ve already seen this — it’s by now rather old, but just in case — you’ll certainly recognize the authors’ names:
http://www.cmar.csiro.au/sealevel/downloads/797655_16br01_slr_080911.pdf
Briefing: a post-IPCC AR4 update on sea-level rise
“There is increasing concern about the potential instability of both the Greenland and the West Antarctic Ice Sheets leading to a more rapid rate of sea-level rise than the current model projections. While our understanding of the relevant processes is limited, it is important to recognize that the uncertainties are essentially one-sided: the processes can only lead to
a higher rate of sea-level rise than current model projections ….”
Re: 398, Hank Roberts.
Many thanks for the good suggestion.