Guest Post by Willis Eschenbach
I’ve been reflecting over the last few days about how the climate system of the earth functions as a giant natural heat engine. A “heat engine”, whether natural or man-made, is a mechanism that converts heat into mechanical energy of some kind. In the case of the climate system, the heat of the sun is converted into the mechanical energy of the ocean and the atmosphere. The seawater and atmosphere are what are called the “working fluids” of the heat engine. The movement of the air and the seawater transports an almost unimaginably large amount of heat from the tropics to the poles. Now, none of the above are new ideas, or are original with me. I simply got to wondering about what the CERES data could show regarding the poleward transport of that energy by the climate heat engine. Figure 1 gives that result:
Figure 1. Exports of energy from the tropics, in W/m2, averaged over the exporting area. The figures show the net of the energy entering and leaving the TOA above each 1°x1° gridcell. It is calculated from the CERES data as solar minus upwelling radiation (longwave + shortwave). Of course, if more energy is constantly entering a TOA gridcell than is leaving it, that energy must be being exported horizontally. The average amount exported from between the two light blue bands is 44 W/m2 (amount exported / exporting area).
We can see some interesting aspects of the climate heat engine in this graph.
First, like all heat engines, the climate heat engine doesn’t work off of a temperature. It works off of a temperature difference. A heat engine needs both a hot end and a cold end. After the working fluid is heated at the hot end, and the engine has extracted work from incoming energy, the remaining heat must be rejected from the working fluid. To do this, the working fluid must be moved to some location where the temperature is lower than at the hot end of the engine.
As a result, there is a constant flow of energy across the blue line. In part this is because at the poles, so little energy is coming from the sun. Over Antarctica and the Arctic ocean, the sun is only providing about a quarter of the radiated longwave energy, only about 40 W/m2, with the remainder being energy exported from the tropics. The energy is transported by the two working fluids, seawater and air. In total, the CERES data shows that there is a constant energy flux across those blue lines of about six petawatts (6e+15 watts) flowing northwards, and six petawatts flowing southwards for a total of twelve petawatts. And how much energy is twelve petawatts when it’s at home?
Well … at present all of humanity consumes about fifteen terawatts (15e+12) on a global average basis. This means that the amount of energy constantly flowing from the equator to the poles is about eight-hundred times the total energy utilized by humans … as I said, it’s an almost unimaginable amount of energy. Not only that, but that 12 petawatts is only 10% of the 120 petawatts of solar energy that is constantly being absorbed by the climate system.
Next, over the land, the area which is importing energy is much closer to the equator than over the sea. I assume this is because of the huge heat capacity of the ocean, and its consequent ability to transport the heat further polewards.
Next, overall the ocean is receiving more energy than it radiates, so it is exporting energy … and the land is radiating more than it receives, so it is getting energy from the ocean. In part, this is because of the difference in solar heating. Figure 2, which looks much like Figure 1, shows the net amount of solar radiation absorbed by the climate system. I do love investigating this stuff, there’s so much to learn. For example, I was unaware that the land, on average, receives about 40 W/m2 less energy from the sun than does the ocean, as is shown in Figure 2.
(Daedalus, of course, would not let this opportunity pass without pointing out that this means we could easily control the planet’s temperature by the simple expedient of increasing the amount of land. For each square metre of land added, we get 40 W/m2 less absorbed energy over that square metre, which is about ten doublings of CO2. And the amount would be perhaps double that in tropical waters. So Daedalus calculates that if we make land by filling in shallow tropical oceans equal to say a mere 5% of the planet, it would avoid an amount of downwelling radiation equal to a doubling of CO2. The best part of Daedalus’s plan is his slogan, “We have to pave the planet to save the planet” … but I digress).
Figure 2. Net solar energy entering the climate system, in watts per square metre (W/m2). Annual averages.
You can see the wide range in the amount of sunlight hitting the earth, from a low of 48 W/m2 at the poles to a high of 365 W/m2 in parts of the tropics.
Now, I bring up these two Figures to highlight the concept of the climate system as a huge natural heat engine. As with all heat engines, energy enters at the hot end, in this case the tropics. It is converted into mechanical motion of seawater and air, which transports the excess heat to the poles where it is radiated to space.
Now, the way that we control the output of a heat engine is by using something called a “throttle”. A throttle controls the amount of energy entering a heat engine. A throttle is what is controlled by the gas pedal in a car. As the name suggests, a throttle restricts the energy entering the system. As a result, the throttle controls the operating parameters (temperature, work produced, etc.) of the heat engine.
So the question naturally arises … in the climate heat engine, what functions as the throttle? The answer, of course, is the clouds. They restrict the amount of energy entering the system. And where is the most advantageous place to throttle the heat engine shown in Figure 2? Well, you have to do it at the hot end where the energy enters the system. And you’d want to do it near the equator, where you can choke off the most energy.
In practice, a large amount of this throttling occurs at the Inter-Tropical Convergence Zone (ITCZ). As the name suggests, this is where the two separately circulating hemispheric air masses interact. On average this is north of the equator in the Pacific and Atlantic, and south of the equator in the Indian Ocean. The ITCZ is revealed most clearly by Figure 3, which shows how much sunlight the planet is reflecting.
Figure 3. Total reflected solar radiation. Areas of low reflection are shown in red, because the low reflection leads to increased solar heating. The average ITCZ can be seen as the yellow/green areas just above the Equator in the Atlantic and Pacific, and just below the Equator in the Indian Ocean.
In Figure 3, we can see how the ITCZ clouds are throttling the incoming solar energy. Were it not for the clouds, the tropical oceans in that area would reflect less than 80 W/m2 (as we see in the red areas outlined above and below the ITCZ) and the oceans would be much warmer. By throttling the incoming sunshine, areas near the Equator end up much cooler than they would be otherwise.
Now … all of the above has been done with averages. But the clouds don’t form based on average conditions. They form based only and solely on current conditions. And the nature of the tropical clouds is that generally, the clouds don’t form in the mornings, when the sea surface is cool from its nocturnal overturning.
Instead, the clouds form after the ocean has warmed up to some critical temperature. Once it passes that point, and generally over a period of less than an hour, a fully-developed cumulus cloud layer emerges. The emergence is threshold based. The important thing to note about this process is that the critical threshold at which the clouds form is based on temperature and the physics of air, wind and water. The threshold is not based on CO2. It is not a function of instantaneous forcing. The threshold is based on temperature and pressure and the physics of the immediate situation.
This means that the tropical clouds emerge earlier when the morning is warmer than usual. And when the morning is cooler, the cumulus emerge later or not at all. So if on average there is a bit more forcing, from solar cycles or changes in CO2 or excess water vapor in the air, the clouds form earlier, and the excess forcing is neatly counteracted.
Now, if my hypothesis is correct, then we should be able to find evidence for this dependence of the tropical clouds on the temperature. If the situation is in fact as I’ve stated above, where the tropical clouds act as a throttle because they increase when the temperatures go up, then evidence would be found in the correlation of surface temperature with albedo. Figure 4 shows that relationship.
Figure 4. Correlation of surface temperature and albedo, calculated on a 1°x1° gridcell basis. Blue and green areas are where albedo and temperature are negatively correlated. Red and orange show positive correlation, where increasing albedo is associated with increasing temperature.
Over the extratropical land, because of the association of ice and snow (high albedo) and low temperatures, the correlation between temperature and albedo is negative. However, remember that little of the suns energy is going there.
In the tropics where the majority of energy enters the system, on the other hand, warmer surface temperatures lead to more clouds, so the correlation is positive, and strongly positive in some areas.
Now, consider what happens when increasing clouds cause a reduction in temperature, and increasing temperatures cause an increase in clouds. At some point, the two lines will cross, and the temperature will oscillate around that set point. When the surface is cooler than that temperature, clouds will form later, and there will be less clouds, sun will pour in uninterrupted, and the surface will warm up.
And when the surface is warmer than that temperature, clouds will form earlier, there will be more clouds, and higher albedo, and more reflection, and the surface will cool down.
Net result? A very effective thermostat. This thermostat works in conjunction with other longer-term thermostatic phenomena to maintain the amazing thermal stability of the planet. People agonize about a change of six-tenths of a degree last century … but consider the following:
• The climate system is only running at about 70% throttle.
• The average temperature of the system is ~ 286K.
• The throttle of the climate system is controlled by nothing more solid than clouds, which are changing constantly.
• The global average surface temperature is maintained at a level significantly warmer than what would be predicted for a planet without an atmosphere containing water vapor, CO2, and other greenhouse gases.
Despite all of that, over the previous century the total variation in temperature was ≈ ± 0.3K. This is a variation of less than a tenth of one percent.
For a system as large, complex, ephemeral, and possibly unstable as the climate, I see this as clear evidence for the existence of a thermostatic system of some sort controlling the temperature. Perhaps the system doesn’t work as I have posited above … but it is clear to me that there must be some kind of system keeping the temperature variations within a tenth of a percent over a century.
Regards to all,
w.
PS—The instability of a modeled climate system without some thermostatic mechanism is well illustrated by the thousands of runs of the ClimatePredictionNet climate model:
Note how many of the runs end up in unrealistically high or low temperatures, due to the lack of any thermostatic control mechanisms.
Bob Weber says:
December 24, 2013 at 12:49 pm
Despite asking, I still haven’t been given a name by anyone here of a better long-range weather forecaster. Is there a problem with finding a brave enough soul who has the skill to make good 30-45 day forecasts? I don’t mean “Caleb Weatherbee” either, even though whoever that is has made a similar winter outlook for 2013/14 as did Piers.
Piers’ forecasts generally work out for the purposes I and his other customers need them for, and I know no one is going to be right all the time when it comes to these issues because of the chaos in the system and of course timing. Expecting perfection from anyone in forecasting is totally completely unreasonable. Back to your regularly scheduled program…
Merry Christmas all.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
And you Bob…
The reason you haven’t received the name of a “better” long-range forecaster is …… Because long range forecasting CANNOT be done. Just CANNOT be done ….. other than in the broadest of statistical terms.
This is my (well one) problem with Corbyn – he makes people think we can. Just not possible my friend.
Look, just think critically think about it. HOW is it possible for someone (note NOT a supercomputer as used in complex NWP forecasts) to produce detailed regional forecasts. Really?
Anyone who knows enough about weather knows full well it is just NOT possible. Full stop, and most probably never will be. Weather is highly chaotic and therefore unpredictable (beyond around 7 days at best).
How could he do it. Does his sunspot number/distribution equate to predictable detail 30 days or whatever away.
As I say, if he has a working method he should put aside his business model and revert to a scientific model – and donate it to mankind and receive the plaudits.
The only known weather effects of solar variation in the sunspot cycle, is that at low amplitude where (it’s theorised) a weak solar wind allows galactic cosmic rays to impinge on the Stratosphere. In winter this has the effect of destroying O3 within the stratospheric vortex. This causes warming and as a result weakens/disrupts the vortex. With time this propagates downward to the tropospheric vortex causing it to weaken, and reflect at the surface by forming high pressure. This is what lies behind colder winters regionally as Arctic air is diverged away from the Arctic (normally we have the opposite – with Low pressure dominating the Arctic and that is a convergent flow tending to keep the coldest air “locked-up”).
Aside from that – and the effect can take ~3 weeks to propagate to a surface effect – Solar variation does not have a noticeable affect on “weather”.
Barack Obama 20xx: ““If you like your health care plan, you can keep it. Period.”
Willis 12:34pm: “The key is that with an argon atmosphere, the only thing radiating is the surface. Period.”
Always investigate further in the case of: “..something stated. Period.”
An argon atm. would feebly absorb/emit IR both from/toward TOA space AND from/toward the surface. Because argon has mass. It would also convect where a layer is heated from below.
*****
Willis 1:22pm: “..an argon atmosphere, which has an emissivity in the relevant shortwave and longwave bands ≈ 0”
That’s better. No “Period.” Argon having mass feebly absorbs/emits both BOA and TOA emissivity ~0 and not 0.0.
I agree with Kristian above who points out that, for a circulation to be established, a higher cooler parcel of air only needs to be denser than the warmer parcel coming up behind. It does not need to radiate to space in order for it to be pushed to one side, find itself denser than the air
below it and start to descend.
As regards Willis’s comments I agree with Paul who had the last word over at:
http://wattsupwiththat.com/2012/01/13/a-matter-of-some-gravity/
That deals with the remaining points of substance regarding my earlier posts.
These issues being at the heart of AGW theory I expect further engagements in the future.
With that I will withdraw from this thread and wish everyone a Merry Christmas and Happy New Year.
No that is not what we are saying.
As stated above you have a conservation of energy equality which is unavoidable. To use your own analogy, if you build a very tall perfectly insulated silo and filled it with a gas in a gravity field you would have by definition (yours) a column with no temperature gradient (remember it is a perfectly insulating container which does not allow heat loss by either conduction or radiation. ) so that the sum of gravitational, kinetic, thermal and pressure potential energy was constant at all levels of the column. The gravitational potential energy must by definition increase as you go from bottom to top. If the gas is quiet and not in motion, but isothermal the only other form of potential energy available to sum out to zero the gravitational potential energy gradient is pressure (in your hypothetical case).
Under the conditions you imposed there is one and only one outcome, maximum possible pressure gradient and zero temperature gradient. Sum of pressure potential energy and gravitational potential energy is uniform at all levels in the silo, kinetic energy of mass motion (convection) is zero and temperature is isothermal.
The problem is in the real world you don’t have a perfectly insulating column and you have an air column that loses heat at the top due to radiant heat loss. Since all real materials must radiate electromagnetic energy at some frequency (IR, microwave, florescence in the visible and UV spectrum and all other manner of energy loss). You lose or gain heat at various points in the column depending on the net heat gain or loss at each point in the gas column.
It in a real world has a continuous heat gain from the bottom due to heating at the ground surface and through out the column due to sun light absorbed by the gases in the column. This forces a temperature gradient in combination with the pressure gradient. The pressure gradient drops and the temperature gradient increases from your ideal perfectly insulated zero heat gain heat loss example.
In a real column with heat gain and loss you get both a pressure gradient and a temperature gradient. Since outer space has a background radiant temperature of 2.7 K you are far far away from your perfectly insulated ideal case.
If you could figure out a way to make the column of air have a uniform pressure from top to bottom you would find you had a huge temperature gradient and no pressure gradient. (it would be very hot at the top and very cold at the bottom to make this happen)
These temperature pressure gradients are absolutely required by the physical laws we all agree on:
….. conservation of energy
….. interchangeability of different types of potential energy
….. ideal gas law
….. Law of gravity (and how gravitational potential energy varies with altitude above a massive object)
A column of air in a gravity field that has heat flow from the low gravitational potential end to the high gravitational potential end, absolutely positively Must have an equal and opposite energy gradient (usually temperature) or it violates the conservation of energy equality.
Konrad says:
December 23, 2013 at 6:24 pm
Thanks for that, Konrad. It’s a thick and long thread, and I don’t always catch everything. A polite reminder is never out of line.
See my answer above about what happens in a GHG-free atmosphere. Short answer is no, without radiative cooling the planetary circulation would mostly stop. I say “mostly” because of the uneven heating of the planet. I suspect that there would still be a slow equator to pole circulation and return, even without radiative cooling of the atmosphere.
In a way, however, it’s a trick question. The Hadley, Ferrel, and Polar cells are mostly powered by the massed thunderstorms at the ITCZ. These thunderstorms are powered by solar heat, and require water as their working fluid.
But if there is water, there is radiative cooling at altitude. So by specifying no radiative cooling, you have not only ruled out the circulation due to radiative cooling and the resulting lapse rate,
You have also ruled out the circulation due to the ITCZ thunderstorms, which can’t exist without water.
Regards,
w.
Larry Ledwick says, December 24, 2013 at 1:17 pm:
“Yes you are correct that decompressional cooling due to the increase in altitude trades temperature/pressure for gravitational potential energy. Thus the rising parcel of air will cool as it rises, but its total energy will remain constant!”
No. It cools because it loses energy. It transfers its gained energy (from surface heating) to the atmosphere at large (the air masses surrounding it, into which it expands), warming it, by doing work on it.
This is how the atmosphere is warmed by convection. If the rising air just took the heat from the surface and brought it ‘up on high’ to hide it away as potential energy, then the atmosphere would never heat from convection, it could never get warmer this way.
Read up on how the adiabatic process works:
http://en.wikipedia.org/wiki/Adiabatic_process#Adiabatic_heating_and_cooling
Willis Eschenbach says:
“Thanks, Ulric, for a good question. It would speed up when it has more incoming energy and the losses equal the inputs. This appears to be the case, for example, over the “Pacific Warm Pool”, which never gets over about 30°C or so.”
I do follow what are saying about an upper limit to tropical surface temp’s, but my point was if there is more energy shifted polewards, total average temp’ should go up, unless the tropics drop at the same time of course. Though what I am seeing from a solar forcing perspective is that when energy input is less, is when there is more poleward transport of energy, and El Nino conditions in the Pacific. Which sums up what I think is controlling the throttle, and in which direction it functions.
@ur momisugly Kristian says:
December 24, 2013 at 2:23 pm
I am very familiar with how adiabatic compression works you are mixing apples and oranges.
The adiabatic process (by itself) results in no heat energy gain or loss only in conversion of pressure energy (from the gravity gradient) to thermal energy. The sum of pressure, gravity and temperature (in the absence of conduction, advection and radiation) is constant there is no heat gain or heat loss.
Sustained convection like you see in a thunder storm is only possible in an unstable atmosphere where as the air parcel rises it is heated by energy released by the latent heat of water vapor and freezing of water crystals. This is what drives sustained convection.
At the ground surface where you have a stable atmosphere, the heated air rises and mixes with the adjacent air transferring energy by conduction and advection as you describe but that is not an adiabatic process.
The very definition of adiabatic is “without heat loss or gain”
Bob Weber says:
“A good recent example of a likely “successful” teleconnection: there was significant solar activity in the last week of October; protons elevated on Oct 28, spiking later, which was the buildup to Typhoon Haiyan, which ran from Nov 3-11, peaking Nov 7. Just a coincidence eh? We’ll see.
Did you break out laughing yet?”
Well actually yes because these are the teleconnections:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml
“Despite asking, I still haven’t been given a name by anyone here of a better long-range weather forecaster. Is there a problem with finding a brave enough soul who has the skill to make good 30-45 day forecasts? I don’t mean “Caleb Weatherbee” either, even though whoever that is has made a similar winter outlook for 2013/14 as did Piers.”
I was thrashing the pants off him with temperature forecasts all the time I was working with him and since, he was very reluctant to give me credit for it though, while nonetheless highly interested in knowing how I was doing it and what I was going to forecast.
Merry Christmas.
I’ll have to come back on a couple of points.
Kristian said:
“If the rising air just took the heat from the surface and brought it ‘up on high’ to hide it away as potential energy, then the atmosphere would never heat from convection”
The atmosphere doesn’t heat from convection.It heats via conduction from the surface which leads to convection and the convective overturning converts kinetic to potential and back again. The work that is done to lift against the force of gravity cools the air by creating potential energy from kinetic energy and the work done on descent with the force of gravity warms the air by creating kinetic energy from potential energy.
Here is something for Willis to think about:
The S-B equation applies ONLY where there is zero interference with the in / out radiative flux from any sort of atmosphere.
Argon does not have zero interference. It will interfere with the radiative flux but admittedly only by a tiny fraction above zero.
The thing is that ANY interference with the radiative flux will cause uplift off the surface and once uplift occurs the amount of energy absorbed by conduction is related to MASS and NOT radiative capability.
Thus even an Argon atmosphere will lift off the surface and thereafter acquire energy via conduction the quantity of which will be related to its mass. Obviously, the amount of energy acquired by conduction will be way out of proportion to its radiative capability.
Uneven surface heating and the inevitable decline in temperature with height will do the rest and a fully convective circulation cannot be prevented.
Meanwhile the S-B equation will still be satisfied but as Leif points out that will be at some point above the surface and that point will be determined primarily by the amount of energy that the mass of the Argon acquires via conduction.
Sorry, should have said:
that point (where S-B is satisfied) will be determined by the amount of energy that the mass of the Argon acquires via its radiative capability.
i’e. not far off the surface due to its low radiative capability.
Meanwhile the overall height of the atmosphere will be determined by the amount of energy that the Argon acquires via conduction.
Ulric I’d sure like to know where I can get your USA monthly forecasts if you have them available to the public. Thank you for the teleconnections info. I am talking about the buildup in the near-earth space environment of protons and electrons following earth-directed solar storms, and the pretty regular coincidence of extreme earth weather events that occur shortly after satellites measure these solar particle flows. That’s all for now.
Trick says:
December 24, 2013 at 1:39 pm
You are accusing me of lying like Obama? And for what?
For all practical purposes, the emissivity of argon in both short- and longwave is ZERO at earth’s temperatures. So you’re gonna get all nasty and accuse me of being like the Liar-In-Chief because the emissivity of argon is 0.000000001 instead of zero? A difference that makes absolutely no difference?
Egads, sire, you are an unpleasant little man.
Trick, your credibility with me just went to zero, and your odds of getting any future response are dropping fast. You’re willing to try to slime me and call me a liar because of a difference too small to be measured. Not good in any social arena, my friend.
A gentleman would apologize for that unwarranted and untrue accusation. I await your answer.
w.
Willis 3:39pm! As you often write – if you quote my words exactly then use their meaning exactly. Not write your own words for what I write & ask my apology for your meaning.
Argon cannot have both 0.0 emissivity as you write and the correct non-zero emissivity also as you write. One of your meanings has to be incorrect. I point out the 0.0 Ar emissivity is your incorrect statement. A little humor was intended. Very little it turns out.
Obama was incorrect initially. He corrected himself subsequently when fact checking pointed that out to him; so I chose a positive example. Your turn. The magnificent climate heat engine can be a positive learning experience in discussion, a very broad, tough subject to fact check. Broad, tough as healthcare.
Larry Ledwick says, December 24, 2013 at 2:44 pm:
“I am very familiar with how adiabatic compression works you are mixing apples and oranges.
The adiabatic process (by itself) results in no heat energy gain or loss only in conversion of pressure energy (from the gravity gradient) to thermal energy. The sum of pressure, gravity and temperature (in the absence of conduction, advection and radiation) is constant there is no heat gain or heat loss.”
Sorry, Larry, but you seem to be the confused one here. The air parcel expanding actually has its internal energy (U) reduced by the process … that’s why it cools.
No energy is transferred out of the air parcel as HEAT (Q), that is correct. However, energy is transferred out of the air parcel as WORK (W). (ΔU = Q – W.)
That’s what adiabatic cooling is all about.
Remember, this is your original statement, Larry, the one I’m reacting to:
“Yes you are correct that decompressional cooling due to the increase in altitude trades temperature/pressure for gravitational potential energy. Thus the rising parcel of air will cool as it rises, but its total energy will remain constant!” (My emphasis.)
Mass- Kristian says:
December 24, 2013 at 2:23 pm
Larry Ledwick says, December 24, 2013 at 1:17 pm:
“Yes you are correct that decompressional cooling due to the increase in altitude trades temperature/pressure for gravitational potential energy. Thus the rising parcel of air will cool as it rises, but its total energy will remain constant!”
No. It cools because it loses energy. It transfers its gained energy (from surface heating) to the atmosphere at large (the air masses surrounding it, into which it expands), warming it, by doing work on it.-
No. Larry Ledwick explains it well.
In terms of the troposphere region one should consider rising air as parcel of air, rather than individual molecules.
Or another way to say this is a single molecule of gas has zero buoyancy.
But parcel of air can have buoyancy.
So you put your hand over flame, and it’s hot a foot above such flame. If you only consider molecules as individuals, this does not work- you can’t explain why the hot air goes up, rather than sideways or down.
Second you never actually ever lose energy. It’s always transfer into different forms of energy.
So if “cools because it loses energy”, the question where and how do you “lose energy”- where does the energy go?
And I think Larry Ledwick explains well.
All surface heating of atmosphere is stored in the atmosphere. It has a lifetime.
I would say it depends how define lifetime terms how long it’s stored.
You can’t follow the energy by single molecule, because air molecules transfer energy
in less than nanosecond and distances nanometers. Therefore one follow energy a
group of molecules which retain most of the energy you might want to follow- hence a parcel
of air.
Your hand over a flame shows the direction of such parcel of air
If you just want follow the energy in term net bank accounts, than one could say roughly
the lifetime is less than a day or hours. If want try to follow your specific chunk of energy
in sea of energize atmosphere, pick your number- centuries if you like.
Depending how do accounting. In other words, you take the total amount heated air in say
24 hour period, globally, and divide that into the total energy of the atmosphere:
Toal mass of atmosphere divided by 2 in which you times “averaged” velocity of entire atmosphere in meter per second. Giving Total Joules of energy in an atmosphere.
And divide Total Joules by amount of joules of heating of gas per your 24 hour. And get some number like centuries of time, or decades or whatever it is.
And matters where some parcel of air is heated- one could make this vastly complicated.
But general the air heated when in sunlight and cools when sun goes down. And if in a Temperate Zone one gets large seasonal changes- or the warmed air parcel has longer lifetime in the summer.
Stephen Wilde says, December 24, 2013 at 3:00 pm:
“Kristian said:
“If the rising air just took the heat from the surface and brought it ‘up on high’ to hide it away as potential energy, then the atmosphere would never heat from convection”
The atmosphere doesn’t heat from convection. It heats via conduction from the surface which leads to convection and the convective overturning converts kinetic to potential and back again.”
Not according to your description, Stephen. There the surface air warms from receiving heat conductively from the surface, but then convection brings it aloft, where the air cools back again without passing any energy on – the heat is just gone! The energy is apparently there, just not the temperature. With radiative loss to space then included, the atmospheric temperature would start dropping.
“The work that is done to lift against the force of gravity cools the air by creating potential energy from kinetic energy (…).”
The lifting air does work on its surrounding air masses by expanding into them, thus cooling while the atmosphere at large warms ever so slightly. The lifting air loses internal energy. This energy is passed on to the rest of the atmosphere. That’s what happens.
Conduction is what heats the surface air parcel. Convection is what brings that energy into the atmosphere, making it a little bit warmer in total than what it was before the surface heat entered the surface air parcel (disregarding the concurrent radiation loss to space).
Stephen 3:00pm: “The S-B equation applies ONLY where there is zero interference with the in / out radiative flux from any sort of atmosphere.”
Zero interference? What does that mean exactly? Where is this in the real S-B derivation?
Your physics must be the Stephen-B equation. In the real S-B, the brightness of the light emitted by BB is given by Planck’s law, which is so good that it has 3 natural constants in it. Not many laws can boast of that. A real S-B limitation is that the body emitting be convex which a globe is good at being. This comes from the limitation in the derivation that a real S-B body does not emit to itself, follows cosine law.
Willis Eschenbach says, December 24, 2013 at 3:39 pm:
“For all practical purposes, the emissivity of argon in both short- and longwave is ZERO at earth’s temperatures. So you’re gonna get all nasty and accuse me of being like the Liar-In-Chief because the emissivity of argon is 0.000000001 instead of zero? A difference that makes absolutely no difference?”
But apparently a specific gas layer 5 kilometres up from the global surface, in the middle of the convective troposphere, holding a mean temperature of 255K and containing on average less than 0.5% of so-called GHGs (and more than 99.5% of N2, O2 and Ar) all of a sudden attains an emissivity of 1 to emit the entire Earth flux to space of 239 W/m^2. Impressive!
Stephen 3:00pm: “Thus even an Argon atmosphere will lift off the surface and thereafter acquire energy via conduction the quantity of which will be related to its mass.”
Each isolated atm. layer transfers energy mainly by convective (mass motion unlike solids), then by conductive and radiative energy transfer. Lord Kelvin figured out, in an atm., convection was dominant energy transfer in an 1862 paper, you remain behind in your reading assignments.
******
Kristian 5:06pm, Larry 2:44pm: Ascending parcels expand (cool) and descending parcels compress (warm). Gas parcel enthalpy is the conserved quantity for the parcel control volume.
******
Larry 2:03pm et. al.:
Unforced mixing increases the entropy up to a max. (unless externally forced down). Only in the absence of gravity would the equilibrium temperature be isothermal.
-Here is something for Willis to think about:
The S-B equation applies ONLY where there is zero interference with the in / out radiative flux from any sort of atmosphere.-
I would say S-B equation applies, only as rough guess.
And the way it’s averaged really messes it up.
Or to restate what you saying S-B equation only applies when dealing energy exchanges
occurring near the speed of light. When involves trapping energy or storing energy and you have problem with S-B equation.
I would say that to assume the only way to trap or store energy is with greenhouse gases is
quite mad.
And to assume greenhouse gas store most of energy of the sun is wrong.
Trick says, December 24, 2013 at 5:43 pm:
“In the real S-B, the brightness of the light emitted by BB is given by Planck’s law, which is so good that it has 3 natural constants in it. Not many laws can boast of that.”
Both Stefan-Boltzmann and Planck deal specifically with radiation and only that. Whenever conduction/convection/evaporation enter the stage, their results are no longer valid. Because the situation is no longer a BB in a vacuum situation. Energy no longer escapes solely through radiation.
That’s why the S-B equation isn’t applicable for the surface of the Earth, or for any specific atmospheric layer above it. On Earth, it would only give ‘correct’ results for an object much, much warmer than its surroundings (more than 3 times in absolute temperature), because then we could disregard convective heat loss and consider the object a pure/ideal emitter to space.
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/cootime.html
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html
For Earth’s surface? No. Any layers within the atmosphere? No.
gbaikie says, December 24, 2013 at 5:34 pm:
“Second you never actually ever lose energy. It’s always transfer into different forms of energy.
So if “cools because it loses energy”, the question where and how do you “lose energy”- where does the energy go?
And I think Larry Ledwick explains well.”
Did you even read what I wrote?
The energy disappears from the expanding air parcel. It goes to the air masses surrounding it. It doesn’t disappear from the atmosphere as a whole. Until it’s radiated away to space.
Adiabatic cooling specifically happens because of energy loss, only not through any transfer of HEAT (Q), but through WORK (W) performed.
Kristian 6:24pm: “Both Stefan-Boltzmann and Planck deal specifically with radiation and only that. ”
Yes, of course.
“Whenever conduction/convection/evaporation enter the stage, their results are no longer valid. Because the situation is no longer a BB in a vacuum situation.”
A vacuum situation is not an assumption in the Planck or S-B derivation, only that the system be in thermal equilibrium, convex which is the usual reasonable assumption for sun, earth, atm. system over eons.
This BB necess. emitting to vacuum seems to be a popular misconception, the source of which I have not been able to track down. Neither of your links notes a vacuum requirement or any link I can find and it is not mentioned as a requirement in Planck 1914, Brehm 1989 or Bohren 2006.
Perhaps you have a cite for your assertion I can fact check. Dependencies include chemical composition, physical structure, condensed matter (solid, liquid, gas, plasma), cosine law, wavelength et. al. but not a vacuum that I can find.