Pressure induced changes in the surface temperature of Triton – Neptune’s largest moon

Posted: June 8, 2012 by tallbloke in Astronomy, Astrophysics, atmosphere, Measurement, solar system dynamics

Thanks once again to Ned Nikolov, who has drawn attention to this press release from the Hubble Space Telescope website. It seems that real astrophysicists don’t have a problem proposing that a rise in the surface temperature of a celestial body can be brought about by an increase in the atmospheric mass of an inert gas… Or at least that that was the case back in 1998, when this press release dates from.  You can easily spot the GHG caveat intro sections that doesn’t sit consistently with the rest of the piece.

hubblesite.org News Release Number: STScI-1998-23
Hubble Space Telescope Helps Find Evidence that Neptune’s Largest Moon Is Warming Up

Sub Neptunian Hemisphere of Triton

Observations obtained by NASA’s Hubble Space Telescope and ground-based instruments reveal that Neptune’s largest moon, Triton, seems to have heated up significantly since the Voyager spacecraft visited it in 1989.

“Since 1989, at least, Triton has been undergoing a period of global warming – percentage-wise, it’s a very large increase,” said James L. Elliot, an astronomer at the Massachusetts Institute of Technology (MIT), Cambridge, MA. The warming trend is causing part of Triton’s frozen nitrogen surface to turn into gas, thus making its thin atmosphere denser. Dr. Elliot and his colleagues from MIT, Lowell Observatory, and Williams College published their findings in the June 25 issue of the journal Nature.

Even with the warming, no one is likely to plan a summer vacation on Triton, which is a bit smaller than Earth’s moon. The five percent increase means that Triton’s temperature has risen from about 37 degrees on the absolute (Kelvin) temperature scale (-392 degrees Fahrenheit) to about 39 Kelvin (-389 degrees Fahrenheit). If Earth experienced a similar change in global temperature over a comparable period, it could lead to significant climatic changes.

Triton, however, is a very different and simpler world than Earth, with a much thinner atmosphere, no oceans, and a surface of frozen nitrogen. But the two share some contributing factors to global warming, such as changes to the Sun’s heat output, how much sunlight is absorbed and reflected by their surfaces, and the amount of methane and carbon monoxide (greenhouse gases) in the atmosphere.

“With Triton, we can more easily study environmental changes because of its simple, thin atmosphere,” Elliot explained. By studying these changes on Triton, the scientists hope to gain new insight into Earth’s more complicated environment.

Elliot and his colleagues explain that Triton’s warming trend may be driven by seasonal changes in its polar ice caps. Triton is approaching an extreme southern summer, a season that occurs every few hundred years. During this special time, the moon’s southern hemisphere receives more direct sunlight, which heats the polar ice caps. “For a northern summer on Earth, it would be like the Sun being directly overhead at noon north of Lake Superior,” Elliot said.

The scientists are basing a rise in Triton’s surface temperature on the Hubble telescope’s detection of an increase in the moon’s atmospheric pressure, which has at least doubled in bulk since the time of the Voyager encounter.

Any nitrogen ice on Triton that warms up a little results in a considerable leap in atmospheric pressure as the vaporized nitrogen gas joins the atmosphere. Because of the unusually strong link between Triton’s surface ice temperature and its atmospheric pressure, Elliot says scientists can infer a temperature rise of two Kelvin (three degrees Fahrenheit) over nine years.

Elliot and his colleagues list two other possible explanations for Triton’s warmer weather. Because the frost pattern on Triton’s surface may have changed over the years, it may be absorbing a little more of the Sun’s warmth. Alternatively, changes in reflectivity of Triton’s ice may have caused it to absorb more heat.

[My Bold] Full press release here: 

For those interested, Ned mailed me this paper: Triton_Pressure_Temperature_Study_2010,  which details a closer look at the atmosphere of Triton. Later today I’ll track down the Nature article and add any relevant material.

Comments
  1. Nick Stokes says:

    TB,
    I didn’t see anywhere where they say pressure causes warming. They are saying warming evaporates nitrogen, which makes more atmosphere, hence more pressure. It’s the density of atmosphere that they measure.

    “The warming trend is causing part of Triton’s frozen nitrogen surface to turn into gas, thus making its thin atmosphere denser.”

  2. Harriet Harridan says:

    TB: “You can easily spot the GHG caveat intro sections that doesn’t sit consistently with the rest of the piece.”

    Of course. We can’t handle the truth. 🙂

  3. Hi Nick: Maybe we’re seeing a feedback forcing here. The increase in insolation starts the ablation of the solid Nitrogen, which then increases atmospheric mass and surface pressure, which then causes the surface temperature to rise further, and more quickly than would otherwise occur. 2C in a decade for a Moon that far from the Sun is pretty impressive global warming doncha think? 😉

  4. Stephen Wilde says:

    This is useful:

    http://www.st-andrews.ac.uk/~dib2/climate/pressure.html

    “Influence of Pressure and Density on Temperature: The Demijohn experiment:

    The relationship between density and pressure can be demonstrated in a corked demijohn combined with a bicycle pump. As air is pumped into the demijohn, the temperature (measured by a thermistor probe) increases. The increase in temperature is due to an increase in density (more air is pumped into the jar, increasing its mass compared to an equivalent volume of air in the surrounding room), and an associated increase in pressure. When the jar is depressurised, the temperature falls to its initial value.
    This is described by the equation p = R r T in the following way:

    Rearranging the equation to examine the effect of variations of pressure and density on temperature, we write: p/(r R) = T
    This says that pressure divided by (density multiplied by a constant) equals temperature
    In the demijohn experiment, we increase the air pressure and the density. As it turns out, the % increase in pressure is greater than the % increase in density, so the term p/rR increases. Hence, temperature increases.
    This explains the general reduction in temperature with altitude (a reduction in temperature due to decreasing pressure).”

    I have seen some suggestions from those who should know better that the initial compression gives a once and for all warming effect which then dissipates when the pressure ceases to increase.

    However that dissipation only occurs because the extra warmth is allowed to leak out into the surrounding environment. If such leakage is prevented the heat from the compression remains indefinitely.

    Above a planetary surface there is continuous compression and decompression going on from adiabatic cooling of rising air and adiabatic warming of descending air. That constant mechanical process keeps replenishing the surface heat.

    Mind you, that presupposes a constant input of energy from a nearby star stirring up the atmosphere by surface heating. Without such an input the heat at the surface would would indeed leak out to space and the atmosphere would congeal on the surface.

    That continuous adiabatic cooling and warming prevents leakage of the surface energy to space via non radiative means and thus effectively seals in the surface heat as determined by surface pressure.

    Since the adiabatic non radiative mechanical processes have sealed in the heat from compression at the surface the only energy that can escape must escape by radiative means and so, of course, the radiative energy out rises to exactly match the radiative energy in at equilibrium.

    Viewed from a point outside the atmosphere the Stefan – Boltzmann Law will apply but only at top of atmosphere where the radiation balance is achieved.

    However the surface temperature can be as much higher than the S -B Equation as the mass of the atmosphere dictates.

    The larger the mass of the atmosphere (even if entirely of non GHGs) the larger the temperature difference between the S – B temperature at top of atmosphere and the the actual temperature at the surface beneath the atmosphere.

    The mistake that has been made is to measure the S-B temperature at a point within the atmosphere instead of at the top of the atmosphere. Usually the so called effective radiating height is used but I say that must be wrong because it is skewed by the vertical temperature profile within the atmosphere.

    I aver that the temperature at the effective radiating height is NOT the temperature predicted by the S-B equation. That temperature must be taken at the top of the atmosphere wherever radiation in exactly balances radiation out.

    If that were to be done the Earth would be seen not to be any warmer than the S-B equation predicts.

    That mistake has been compounded by the failure to recognise the effectiveness of the adiabatic warming of descending air which returns heat back to the surface thereby sealing in the heat acquired at the surface from the initial gravitational compression.

  5. Trick says:

    Stephen Wilde 1:46pm: “..the initial compression gives a once and for all warming effect which then dissipates when the pressure ceases to increase…..constant mechanical process keeps replenishing the surface heat.”

    Control volume (cv) alert! Put a cv around the system. Work comes in to compress then equal and opposite heat goes out to return to original T cv equilibrium. See that by holding gas enthalpy constant (1st Law). If system ideal perfectly insulated, work can’t come in either.

    Nothing reasonable is putting work in continuously “pumping” planetary atmosphere V to warm the surface, gravity does not turn on & off. The sun replenishes the planetary surface heat, ideal atmosphere goes as PV = nRT. V expands, contracts in response when V not held constant w/time.

  6. Stephen Wilde says:

    Trick,

    The sun only replenishes the energy lost to space, not the energy lost from the surface, hence the top of atmosphere radiative balance.

    The energy put into the system by the initial gravitational compression is sealed in by the adiabatic process for as long as the gravitational pull continues.

    The pumping process involved in the adiabatic mechanism is a consequence of density differentials causing air to constantly rise and fall.

    It is true that anything else other than solar input to the top of the amosphere or an increase in atmospheric mass will cause changes in atmosphere volume to keep the initial pressure induced surface temperature stable.

    Gravity doesn’t need to turn on and off. All one needs is equal volumes of air rising against the force of gravity and then descending under the force of gravity. Density differentials do the job of providing the work that is being done continuously.

    Successive compressions and decompressions constantly maintaining the surface temperature from the initial gravitational compression.

    Focus on the effects of adiabatic compression of descending air. The temperature of that air increases steadily as it descends purely as a result of compression (pressure) and at any one time 50% of the entire atmosphere is in the process of descending and being heated in that way.

    The significance of adiabatic compression seems to have been completely overlooked.

  7. ferd berple says:

    Stephen Wilde 1:46pm: “..the initial compression gives a once and for all warming effect which then dissipates when the pressure ceases to increase…..constant mechanical process keeps replenishing the surface heat.”

    Where does it dissipate to? The atmosphere cannot conduct the energy away to space. If the atmosphere has no GHG it cannot radiate this energy away to space either. You cannot destroy the energy. It will not spontaneously dissipate without a mechanism.

    As proposed for CO2, atmospheric conduction must reduce outgoing radiation, by removing from the surface energy that would otherwise be radiated to space. In the absence of GHG in the atmosphere, the planet surface must heat up as a result to restore the outgoing radiation balance, exactly as proposed for CO2.

    Gravity concentrates the energy conducted away from the surface by the atmosphere through two mechanisms: pressure (joules/m^3) and by the conversion between kinetic and potential energy (lapse rate).

    This returns the energy lost to the atmosphere by conduction to warm the cold parts of the surface (night and poles) increasing the average temperature, in a process equivalent to CO2 back-radiation.

    Thus, a plant with an atmosphere and no GHG must be warmer at the surface than a planet without an atmosphere.

  8. Stephen Wilde says:

    Ferd.

    You are responding to an incomplete portion of my first post.

    AGW proponents say that the initial energy from compression dissipates because they use the bicycle pump analogy and of course the pump does cool down subsequently, after the compression has taken place because the warmth leaks out from the pump chamber through the walls to the outside world.

    My point is that such an analogy is wrong. As you confirm, the atmosphere can only lose energy to space by radiation and not by conduction or convection.

    Therefore what the AG proponents have missed is that the energy from the initial gravitational compression is stuck within the atmosphere forever until either the sun goes out or the gravitational field disappears to release the atmosphere to space.

    Otherwise we are agreed. The energy that goes up by non radiative means then comes back to the surface again but I say it is via adiabatic compression.

    The heat created by the initial gravitational compression is stuck within the atmosphere forever and is continuously pumped up and down as a result of density differentials within the atmosphere.

    An entirely separate process independent of the laws of radiative physics.

    Radiative physics only applies to the equilibrium temperature from top of atmosphere outwards. More specifically from the point where energy in equals energy out.

    All else is internal system, non radiative, processing and reprocessing of the initial block of energy derived from atmospheric mass, gravity and pressure.

    GHGs do help with radiation out but if they were able to affect the equilibrium then a single GHG molecule over enough time would either cause the atmosphere to be boiled off or frozen to the surface depending on whether the net effect is warming or cooling. That doesn’t happen so something else must change within the system to prevent it.

    In fact the non radiative processes adjust to offset the effects of compositional variations including GHG quantities.

    The circulation of any planetary atmosphere must self evidently reconfigure as necessary to match radiative outgoing with solar incoming.

    Otherwise a gaseous atmosphere is not possible.

    Only solar input at top of atmosphere and atmospheric mass can set the equilibrium temperature of any given planet. Any other changes just result in a regional redistribution of energy which is then countered by circulation changes in the atmosphere.

    To my mind that cuts through all the confusion and squares the circle.

  9. steveta_uk says:

    Therefore what the AG proponents have missed is that the energy from the initial gravitational compression is stuck within the atmosphere forever until either the sun goes out or the gravitational field disappears to release the atmosphere to space.

    What has the sun going out got to do with it? Energy that is “stuck” in your fantasy world doesn’t require the sun to maintain it, as surely gravity does it all by its magical self.

  10. Stephen Wilde says:

    “What has the sun going out got to do with it?”

    If the sun goes out then there will be no radiation incoming to match radiation outgoing and in due course the atmosphere will cool down enough to congeal on the surface.

    The solar input is required to give the molecules enough energy to form a gas and float free of the surface.

  11. Tenuc says:

    ferd berple says:
    June 8, 2012 at 3:28 pm
    “…The atmosphere cannot conduct the energy away to space. If the atmosphere has no GHG it cannot radiate this energy away to space either…

    Harry Huffman’s work clearly demonstrates that only the ratio of Earth and Venus distance from our Sun is needed to precisely explain each planets temperature ratio at points of equal pressure in the two atmospheres. This means that the level of GHG on each planet is irrelevant regarding temperature and thus the current CAGW CO2 scam is dead (but not yet buried, it seems).

    Link to Harry’s work here…

    http://theendofthemystery.blogspot.co.uk/2010/11/venus-no-greenhouse-effect.html

  12. Stephen Wilde says:

    “If the atmosphere has no GHG it cannot radiate this energy away to space either”

    The ground radiates it to space instead and adiabatic compression is what returns energy to the ground for radiation to space.

    Thus the circulation reconfigures to deliver exactly the right amount of energy back to the ground to enable radiation out to equal radiation in.

    However, radiation out never exceeds radiation in (or not for long) and so the energy from the initial gravitational compression remains locked in the atmosphere.

    There is no mechanism for getting it out again because the atmosphere always reconfigures to maintain balance.

  13. Trick says:

    Stephen Wilde 3:06pm: “The temperature of that air increases steadily as it descends purely as a result of compression (pressure)…”

    Because you’ve just defined it purely that way (control volume adiabatic process). The sun seems to me is the pure reason it is balmy outside today driving PV=nRT; ex Sol no more gravity “pumping” new work = new heat today.

    The sun heats, does work to expand V, opposite gravity force pulls V back down for equal work. This compression originates purely from sun; it cycles in LTE with radiation out if that is what you really mean. Gravity is not used up, Sol is being used up. 1st law applies.

    T=288K is purely from LTE w/sun today. IMO no memory of original compression heat remains, at all. Interesting though, need to see from 1st principles, got a link or ref.? Pretty sure discussed before.

  14. Trick says:

    Tenuc 6:03pm: “Furthermore, since the atmospheric pressure varies as the temperature…”

    Ideally atmospheric pressure varies as PV = nRT. So ideally pressure really varies as P = nRT/V. I went over to the link you posted, same thing:

    “…since the atmospheric pressure varies as the temperature, the temperature at any given pressure level in the Venusian atmosphere..”

    Whoa, that stopped me. Here Venus pressure must vary from Earth’s by n difference also. Venus has more n.

    Seems like can’t use Venus to invoke the “current CAGW CO2 scam is dead” until provide more information about how n varies to compare T of the two planetary systems at same PV.

  15. Stephen Wilde says:

    “The sun seems to me is the pure reason it is balmy outside today driving PV=nRT; ex Sol no more gravity “pumping” new work = new heat today.”

    You can look at that way. Most people do.

    But doing so obscures the truth.

    From the time that equilibrium is reached with solar incoming equalling longwave outgoing the solar incoming has no net effect. Outgoing swaps with incoming and vice versa indefinitely and so each cancels out the other yet at the same time the atmosphere remains balmy well above the temperature of the surrounding space.

    Thus you can look at that remaining residue of energy within the atmosphere as a phenomenon separate from the incoming solar.

    Once one looks at it that way the source is clear. The initial gravitation compression produced a reserve of energy that has never since been lost.

    True, that energy originally came from the sun but it was held back from being lost for a while by that gravitational compression and once stored in the atmosphere it stays there until the sun dies or the atmosphere is lost as a result of a loss of the gravitational field.

    If anything internal to the system (not sun or gravity) changes so that there is no longer an equilibrium then all that happens is a circulation change altering the speed of energy throughput to nearly instantly restore and then once again maintain the equilibrium.

    Climate changes are a consequence of such circulatory adjustments.

  16. Stephen Wilde says:

    “until provide more information about how n varies to compare T of the two planetary systems at same PV.”

    I think Huffman deals with that by referring to the pressure level and not actual height.

    He points out that there is an equivalence at the same pressure level in each atmosphere i.e. the height at which n is the same.

  17. Trick says:

    Stephen – Yeah, thx, I think you make sense. At the start of Earth’s atmosphere, I assume it wasn’t ever at 3K AFAIK or whatever deep space was those many billions of years ago. The sun did not have to heat whole atmosphere from 3K to 288K all alone, the original heat from whatever source (collisions, nuclear decay, friction) could be considered to still be here I suppose since the heat doesn’t flow thru with serial numbers on it to keep track. It is just me – I can’t see a moment before compression & a moment after one time compression with new heat from that ever really happening.

    “…height where n is the same.”

    Not sure how that matters. I scanned down the site Tenuc posted as well as searched several key words, could not find any discussion of the planetary n difference in PV=nRT. Have not found the source paper of the Venus temperatures but from reading the abstract & links supplied at the site, the source paper in 1994 did not get Venus T from thermometer measurements. The 1.176 ratio is so precise I’d like to find & read the orig. paper; would like to see how they so precisely derived Venus P&T profile from occultation of an ultra stable radio signal while pre-knowing earth profiles & (ex ante?) the 1.176 ratio.

    The site mentions hydrostatic lapse rate but that is derived from non-GHG ideal gas and can’t be then used to show no GHE. Earth’s lapse rate is only experimental; ideal theory says it should be a bit different than it is. Lotsa’ other non-ideal stuff happening.

  18. Trick says:

    Stephen & Tenuc – I spent some time googling for “radio occultation” as applied to profile T on other planets which the site Tenuc posted says is the physics of the source it uses for the Venus T profile with the paper paywalled. So not going there. I did, though, find this for free:

    “… radio occultation technique was originally developed at Stanford University and JPL (Jet Propulsion Laboratory) for studies of planetary and lunar atmospheres…. By assumptions of hydrostatic equilibrium, the equation of state, and a simple connection between the refractive index and density of the atmosphere, a temperature and density profile can be computed.”

    So once again, hydrostatic equilibrium assumptions are for non-GHG gases, PV=nRT eqn. of state as we know becomes increasingly inaccurate adding non-ideal empirical corrections at higher pressures. Too, I am left wondering what are the “simple” refraction connection idealized limitations. Need the orig. 1994 paper. Seems like T error bands might be larger than any GHE delta T trying to be found physically. Anyway, that’s it for me.

  19. Trick, The Russians actually landed a probe on Venus – Venera 13 see here http://www.mentallandscape.com/C_CatalogVenus.htm . I understand lots of scientists thought the surface would be somewhat sticky but it did not photograph that way. Thus the actual surface temperature as opposed to the above surface atmosphere temperature maybe less than what is thought.

  20. wayne says:

    Trick, you said “PV=nRT eqn. of state as we know becomes increasingly inaccurate adding non-ideal empirical corrections at higher pressures.” and I’m not sure that is correct. It is more like the parameters used in the equation at anywhere above a low pressures no longer follow the ideal laws. PV=nRT seems to hold with correct parameters.

    This afternoon I delved into Van der Waals, thanks to br1 for stirring my curiosity, darn him. This was going to take way to many words to explain what I found so here so here is the output on my dinky physics calculator:

    # Compute Van der Waals constants for air (80% N2, 20% O2)
    a = 0.8*1.408 + 0.20*1.378     # L²atm/mol
    b = 0.8*0.03913 + 0.20*0.03183 # L/mol
    0.1420576 <== a *= 0.101325 # –$lt; to m³²Pa/mol²
    3.767e-05 <== b *= 0.001 # –$lt; to m³/mol
    
    # Set some constants used
    R  = 8.31446
    V  = 1
    ρ0 = 1.22633      # near US.StdAtm.1976 SL density
    M  = 0.02897
    P0 = 101325
    
    # USING Van der Waals: (P+n²a/V²)(V-nb)=nRT
    
    P = P0
    42.331     <==  n = ρ0/M
    288.151    <==  T = (P+n²*a/V²)*(V-n*b)/(n*R)
    
    # n = mol/m³ from std. 22.414 l/mol at STP 0°C
    n = 44.615        
    T = 288.15
    106786.3   <==  P = (n*R*T)/(V-n*b)-(n²*a/V²)
    
    P = P0
    # same n
    273.452    <==  T = (P+n²*a/V²)*(V-n*b)/(n*R)
    

    See the 288.151 K and 273.452 K. That is the variance imposed on the atmosphere at sea level by Van der Waals forces and they mount to a whopping ~15°C. The density at sea level is lower by about 5% than what ideal law would report if pressure is 101325 Pa and temperature is 288.15K, it pops out 42.33 moles instead of ideal 44.62 moles.

    Of course near TOA the a & b coefficients near zero and ideal is in effect. But that put’s a temperature warp BETWEEN sea level and TOA.

    That basically seems to imply that the sea level to TOA’s lapse rate is affected some 15 degrees away from ideal purely by Van der Walls forces and I keep doubting myself for in the thousands of pages on “climate science” I have never come across these factors mentioned. Everyone just says the atmosphere is “near” ideal and I don’t call a whopping 5% “near”. If this is correct no wonder some of my calculations over the last three years have never matched the way I expected them to.

    (or am I missing something)

    [Reply] Wow! Wayne does it again. Let’s explore this, it looks important.

  21. bwdave says:

    It is interesting that this happened in 1998, given the corresponding spike in Earth’s temperature.
    Also, I wonder if Wayne isn’t just observing that water isn’t an ideal gas.

  22. Stephen Wilde says:

    A ‘warp’ in the vertical temperature profile between sea surface and TOA is exactly what I would expect to see if the temoerature at the actual surface is to differ from the TOA temperature derived from the S-B equations.

    Remember that S-B only applies at a point from TOA uipwards with the ideal height for the measurement being where radiation in equals radiation out. Below that point an atmosphere will interfere with the measurement and the surface temperature below the atmosphere can be any temperature at all as dictated by total atmospheric mass and TOA solar input.

    Anyway wayne comes up with about 15C for Earth which is about half the so called ‘excess’ temperature at the surface referred to as the greenhouse effect.

    Refer next to the standard vertical temperature profile of the atmosphere.

    Surface to tropopause cools, tropopause to stratopause warms, stratopause to mesopause cools then mesopause upwards warms. A ‘W’ shape laid out sideways is a good way to describe it.

    Now, net out the two cooling slopes and the two warming slopes and I think one will find a diference between the warming and cooling slopes of 15C or thereabouts which manifests itself as a net 15C diference between surface and TOA and that portion of any difference between surface and TOA will be entirely attributable to the non ideal nature of the atmospheric gases.

    However AGW theorists take the temperature at the effective radiating height in order to compare the Earth’s ‘actual’ emperature with the temperature it ‘should’ be from the S-B equation.

    They are wrong to do that in my opinion so consider the consequences of doing that.

    The effective radiating height is a height where about half of atmospheric density is beneath it and about half is above it so depending on the relationship between the slopes in that ‘W’ shape there will be a further distortion of the measured outcome as compared to the S-B expectation.

    I suspect that the non ideal features of the atmospheric gases cause a net warp of 15C between surface and TOA and that taking the temperature measurement at the wrong height effectively doubles it due to the height at which the temperature is taken not being an accurate reflection of the entire vertical temperature profile.

    A final point is that on any given planet the size of the warp would be a consequence of the internal air circulation reconfiguring itself to ensure that despite the non ideal nature of the gases the amount of radiation out will nonetheless match radiation in so as to retain system stability.

    The warp preserves PV=nRT despite the non ideal nature of the gases in a real atmosphere.

    I’m not 100% per cent sure on all of that but I think I am on the right general track. Refinements may be necessary. For the time being these are just discussion points.

  23. wayne says:

    Now I am trying to digest that new relationship. Wish I knew a bit more meteorology. Excess energy low in the atmosphere move the lapse rate curve as viewed in a radiosonde skew-t toward the DALR line so what meaning does this 15 degrees have in relation to the 6.5°C/km environmental lapse? That 15 degrees surface to toa would mean about 1.5°C/km. On side I keep coming up with is that it may have no real meaning to the atmosphere at all as we know it, for the ELR is empirical and DALR is computable, and is real, as viewing a radiosonde in the Sahara following the ~10°C/km upward. So where does this 15 degrees fit in?

    Seems though as if part of the hypothetical 33°C ghe, or more the probable the 134 °C by N&Z (288-154), is already accounted for, and caused by, the Van der Waals effects themselves of the atmosphere gases. If that 33°C has any reality then it is reduced to about 273 K or 18°C. Gee, there is 273 K again, seems I hit that figure, unrelated, about a month ago in a comment.

  24. Michael Hart says:

    Stephen,
    “However, radiation out never exceeds radiation in (or not for long) and so the energy from the initial gravitational compression remains locked in the atmosphere.”

    This causes me problems. Radiation out from some temporary ‘hot-spot’ according to SB and 4th power of T, is radiation lost. It cannot be balanced by a later return from the atmosphere, because the atmosphere doesn’t have it. A corresponding ‘cold-spot’ cannot match it because the radiating power is related to the absolute temperature, not an anomaly. That is, a cold and hot spot are not symmetrical and not equivalent, so there must be a net loss or gain.

    Also, if what you claim is true, then what happens to all the built up heat from radionucleides if it could never escape? Or tidal heating?

  25. Trick says:

    Wayne 6:23am – “…more like the parameters used in the equation at anywhere above a low pressures no longer follow the ideal laws.”

    Yeah, reasons PV=nRT becomes increasingly inaccurate – it is a “law” only for ideal gases under certain parameters. Above about 200 hPa to 0 hPa other non-ideal gas weaker molecular level forces kick in winning the force battle and nature falls more & more off the ideal gas non-isothermal lapse from PV=nRT unadjusted eqn. of state and starts heading back to isothermal with h but never quite gets there before expiring.

    At 1000 hPa (~surface) real standard atmosphere (~288K) starts out cooler than PV=nRT by ~14K. Then nature’s real lapse rate is slower than ideal up to ~225 hPa where the real standard atmosphere is now ~20K warmer. After that, the real standard atmosphere is increasingly warmer than ideal falling off the ideal PV=nRT curve; molecular level dynamics become increasingly more important as is intuitive.

    One method of correcting parameters in ideal PV=nRT found googling PV=znRT is here: http://en.wikipedia.org/wiki/Talk%3AZ-factor

  26. Brian H says:

    Edit: “the GHG caveat intro sections that doesn’t sit consistently with the rest of the piece”. XX

    Either — “the GHG caveat intro sections that don’t sit consistently with the rest of the piece”
    or
    “the GHG caveat intro section that doesn’t sit consistently with the rest of the piece”.
    Pick one.

  27. Stephen Wilde says:

    Michael (Hart),

    Radiation lost in excess of incoming (as a result of a temporary hot spot or any other cause) results in a slowdown of outgoing radiation due to a reconfiguration of the air circulation.

    Energy from radionucleides results in a speeding up of outgoing radiation due to a similar reconfiguration.

    Perhaps it would help to look at this way:

    Whatever energy is in the atmosphere at any given moment from ANY source is the sole driver of atmospheric circulation and atmospheric turbulence.

    So, more such energy drives a faster circulation and more turbulence. Less such energy drives a slower circulation with less turbulence.

    The outurn is that radiation out and radiation in are kept steady over time despite variations around the baseline. Nearly all energy in is solar but admittedly there is also a tiny fraction generated from the Earth itself.

    The response of the air circulation is always a negative and sufficient response to ANY change in the energy content of the troposphere.

    The result is that since solar energy received is always matched by longwave out the additional energy that keeps the atmosphere warmer than space never depletes unless the sun weakens or mass is lost from the atmosphere.

    For the Earth as a whole the sum total of all hotspots must always match the sum total of all coldspots because what goes up must come down and what flows poleward must return equatorward.

  28. wayne says:

    Thx Trick, I took that in a too narrow mental view, of one cubic meter at some given location. I see what you mean, of course when out-of-LTE, across entire columns or basically anywhere the variables are in flux, then the ideal laws are no longer accurate and usually not longer of any meaning. See, I tend to look in tight control volumes too (learned a new term)… and sometimes too much being rather new to some of the depths of td. 🙂 But most of the time I know just enough to get in trouble!

    Nice story on the z-factor. That same technique just might work in one other area where I need to filter thousands of outliners using the deviation.

  29. Tim Folkerts says:

    Stephen Wilde says: “From the time that equilibrium is reached with solar incoming equalling longwave outgoing the solar incoming has no net effect. Outgoing swaps with incoming and vice versa indefinitely and so each cancels out the other yet at the same time the atmosphere remains balmy well above the temperature of the surrounding space.

    The initial gravitation compression produced a reserve of energy that has never since been lost.”

    You have the conclusion backwards. There is “roughly” a continuing balance. Any EXTRA energy that has been deposited (nuclear decay in the atmosphere, meteors crashing into the atmosphere) will eventually leak away, leaving only the sunlight/earthlight balance. Or are you saying that the heat from every meteor that ever collided with the earth is still there too?

    Suppose I could suddenly set massive fires all around the world that provided enough energy to warm the atmosphere by 5 C (and then put out all those fires). Would the atmosphere stay 5 C warmer? Of course not. The outgoing IR would increase, cooling the atmosphere until equilibrium was again achieved.

    Only CONTINUED sources of energy will continue to keep anything warm. If I KEPT burning those fires, the temperature would stay elevated. The ~ 0.1 W/m^2 of continued geothermal energy flux provides a slight continued increase in the earths temperature. The continued DWLR from the atmosphere keeps the atmosphere warm. But the heating from a one-time compression billions of years ago has certainly had time to come to equilibrium.

  30. Stephen Wilde says:

    Tim.

    I suggest that you have not understood.

    The atmosphere always reconfigures so that radiation in equals radiation out over enough time. Otherwise there could be no atmosphere.

    That does not mean that there is never an excess either way. The system is in quasi equilibrium constantly oscillating around the temperature set by sun and mass of atmosphere.

    So, any extra energy from anything other than from more solar input or from increased atmospheric mass will indeed leak out as you say. A slightly faster outgoing over incoming for a while will remove the energy input by meteors or volcanoes via a change in the speed or efficiency of the air circulation.

    When you light those massive fires the atmospheric circulation will change to eliminate any extra energy more quickly.

    Part of the elimination process will involve aerosols from the burning spreading round the world and reducing insolation. They could even induce net cooling.

    The basic equilibrium temperature set by solar input and atmospheric mass is still there in the background as a constant whatever happens within the system.

    The price to be paid in climate terms in order to eliminate excess energy would be a fractionally expanded atmosphere with a fractionally more poleward air circulation pattern for a faster exit of energy to space but no higher temperature.

    The system would be slightly out of equilibrium for a while but system energy content stays virtually the same.

    As you say, the change in circulation would continue for as long as the fires keep burning. During that time the energy out might or might not exceed the energy in but in geological terms such fires could only last for the blink of an eye.

    Certain regions on the surface would experience warmer winds as any extra energy flowed past faster on its way out of the system but the system energy content as a whole stays much the same.

    Consider what happened in the late 20th century warming period. The equatorial regions stayed at much the same temperature. The mid latitudes warmed a little but the high polar regions actually cooled especially Antarctica because more zonal jets tend to cut off the poles from incoming warm air flows.

    Thus there was actually very little actual net global surface warming which is why the satellites show much less variation than unrepresentatively placed surface sensors.

    Meanwhile that one time compression from billions of years ago is constantly refreshed by ongoing adiabatic compression which continually replaces the energy lost by ongoing adiabatic decompression.

    Certainly the system has had time to come to equilibrium but that energy from gravitational compression is still there within the atmosphere and it cannot ever get out so long as radiation coming in equals radiation going out over time.

    Even if human emissions of CO2 do have a net warming influence they would come approximately nowhere being unmeasurable compared to the variations caused by sun and oceans alone. We saw climate zone shifts of 1000 miles between MWP and LIA for instance. Can you say how far our emissions shift them ?

    In fact it is likely that non condensing GHGs facilitate energy loss to space by radiating upward instead of having to return energy to the surface via adiabatic compression before radiating out which is the route that non GHGs have to use.

    Furthermore the presence of GHGs radiating to space means that the air circulation has to be less violent in order to match up the energy balance at top of atmosphere. Instead of all the energy having to flow up and down adiabatically and be flung to and fro from night side to day side and from equator to poles some of it gets radiated straight out which reduces the work that the rest of the atmosphere needs to do.

    Overall the net effect of non condensing GHGs is probably neutral and serves to give us a more calm atmosphere than would be the case without them.

    You said:

    “The continued DWLR from the atmosphere keeps the atmosphere warm”

    No it does not. Continuing adiabatic compression keeps the atmosphere warm and the warm atmosphere generates LR in ALL directions but mostly at the surface where density is highest. Strictly speaking the sun doesn’t keep the atmosphere warm because radiation out matches radiation in on average over time.

    You said:

    “The ~ 0.1 W/m^2 of continued geothermal energy flux provides a slight continued increase in the earths temperature”

    Yes it does and the atmosphere expands accordingly leaving surface temperature as it would have been without it.

  31. Brian H says:

    SW;
    Ya, I rather like your square circle. There’s a certain blunt logical inevitability about it. Thx!

  32. Stephen Wilde says:

    Actually on reflection I think one should treat newly generated geothermal energy as a secondary energy source along with solar input such that radiation out will equal the total of solar in plus geothermal in which would give both a greater volume for the atmosphere plus a slightly higher system temperature but by all accounts we are not currently able to measure the top of atmosphere global energy exchange that accurately.

    For climate purposes it can be ignored.

    For climate purposes we are trying to clarify whether simple energy redistribution can raise the system temperature without there being any extra energy supplied by sun, geothermal or atmospheric mass.

    I think it works as follows:

    Troposphere warms from a change in internal system features. Power of the sun and atmospheric mass stay the same. Ignore geothermal for present purposes.

    i) Atmosphere expands from increased energy content due to redistribution of available energy within the system.
    ii) Expanded atmosphere presents a larger surface area to the sun so top of atmosphere solar input rises but the potential warming effect from that cause is negated due to reduced molecular density at the surface
    iii) The larger circulation within the expanded atmosphere removes energy from the system more effectively so the potential warming effect on the surface from the internal system cause is also negated.
    iv) No rise in system equilibrium temperature, total system energy content or surface temperature averaged globally.

    Troposphere warms from increase in solar power and atmospheric mass stays the same.

    i) Atmosphere expands from increased solar energy reaching the top of atmosphere.
    ii) Expanded atmosphere presents a larger surface area to the sun so top of atmosphere solar input rises further but the reduced density at the surface will only deal with the extra energy arriving at top of atmosphere, not the extra energy arriving at the surface.
    iii) The enlarged circulation within the expanded atmosphere removes energy from the system more effectively so equilibrium is regained but since the surface temperature has risen from the extra solar power the enlarged circulation cannot reverse the process.
    iv) There is a rise in system equilibrium temperature, total system energy content and surface temperature averaged globally.

    Troposphere warms from increased atmospheric mass and solar power stays the same.

    i) Atmosphere expands because the extra mass absorbs more energy and keeps it in the system longer before releasing it to space.
    ii) Expanded atmosphere presents a larger surface area to the sun so top of atmosphere solar input rises but the potential warming effect is negated due to reduced molecular density at the surface.
    iii) The enlarged circulation within the expanded atmosphere removes energy from the system more effectively so equilibrium is regained but since the surface temperature has risen from more solar energy retained in the system for longer the enlarged circulation cannot reverse the process.
    iv) There is a rise in system equilibrium temperature, total system energy content and surface temperature averaged globally.

    Can anyone see any problems with that ?

  33. Tim Folkerts says:

    Stephen, you say a few things that are unclear to me. Mostly it boils down to me not knowing which “system” you mean.

    For example, you say “Only solar input at top of atmosphere and atmospheric mass can set the equilibrium temperature of any given planet. ” I would say that only solar input is sufficient to find the equilibrium temperature AS SEEN FROM SPACE of any given planet. Ie if you know the absorbed solar radiation, then you know the emitted IR. If you know the emitted IR, then you know the effective BB temperature. The mass of the atmosphere is irrelevant. This is because the planet as a whole only gains energy from the sun, and only loses energy via IR (ignoring, of course, geothermal energy). For earth, the numbers are ~ 240 W/m^2 absorbed and 255 K. Atmospheric mass is irrelevant.

    But the surface is different. Knowing solar input and atmospheric mass is insufficient. For example, suppose I built a planet 1 AU from the sun. A add an atmosphere of 100.00000% N2 with the same mass as earth’s atmosphere. I paint the surface gray to make the albedo 0.3. I would argue that the surface temperature of this planet would be ~ 255 K.

    In fact, we need to know a LOT more about the atmosphere than just the mass to know the surface temperature. We need to know heat capacity (it determines the lapse rate). We need to know the types and concentrations of GHGs, since these provide IR light to surface, keeping it warm.

    So when you say “iv) No rise in system equilibrium temperature, total system energy content or surface temperature averaged globally.”
    * I agree that the “system” consisting of the planet as a whole (including atmosphere) will have no rise in the effective BB equilibrium temperature.
    * I disagree that the system consisting of the surface but not the atmosphere will not change. The surface can and will change temperature based on changes within the atmosphere.

  34. bwdave says:

    The observed temperature of a body from space represents its heat loss, and must reflect 1)all heat received 2)all previously stored being released that which is released from within, minus 3)all heat being currently stored, None of the three are ever constant.

  35. wayne says:

    No albedo, TimF, in that 100% nitrogen atmosphere? So, average 682 Wm-2 on lit side compared to 682*.70 or ~477 we experience now anywhere near the tropics? Are you still allowing for some mass extinction in the atmosphere and if so which bands and why or why not? Are you counting energy leaving the dark side to also be blackbody, no inter-atmospheric S-B impedance? Are you still counting on the surface to be an ideal blackbody? (Seems like we had this example three years ago.) Oh, there is still dust and particles in the atmosphere I am assuming due to the high equalibrium winds. More, I also assume that dry surface has thermal capacity, it’s going to get rather hot!!, over the boiling point directly under the sun!

    “In fact, we need to know a LOT more about the atmosphere than just the mass to know the surface temperature.”

    I agree with that in your pure, though unrealistic example. I think Stephen is saying it would still be basically 288 k and I tend to agree once you add all of the real factors, or just calculate the same figure from the mass and pressure. Tim, I thought I read you are (or were) a physicist or taught physics, so haven’t you already tackled all of these mathematically as many here have done? Shouldn’t be too hard for someone with your background. The rest of us have to struggle through it.

  36. Stephen Wilde says:

    Tim.

    The thermal capacity of the atmosphere is tiny compared to water and land so it really doesn’t warm the surface.

    Furthermore the atmosphere is constatly in rapid movement both vertically and horizontally so as soon as it warms up from any cause then the energy is whisked away to cooler locations and lost more quickly to space.

    The volume of the atmosphere is highly relevant to the rate of loss of energy from atmosphere to space and the fact is that volume increases and decreases instantly in response to changes in energy content. The amount of such expanson and contraction which results from a given increase in energy is pressure dependent hence the direct relationship with atmospheric mass and thus pressure at the surface.

    That expansion and contraction prevents extra energy in the air from warming the surface. Instead, it is lost to space more quickly.

    There are regional surface temperature changes acoss the surface where warmer air might flow out horizontally for a while before being lifted off the surface but generally the regional changes at the surface balance out to negate each other because air that goes up must come down and air that flows poleward must flow back equatorward.

    So unless there is an increase in total energy available the system cannot warm up as a result of more energy in the atmosphere and there is only more total energy available if solar power input increases or atmospheric mass increases.

    Warming from more GHGs does not involve more energy in the system because it just escapes to space faster as a result of atmospheric expansion and the consequent increase in the size and efficiency of the circulation.

    You do get a miniscule shift in the climate zones but miniscule compared to that caused by sun and ocean variability.

    AGW proponents need to focus on the distance that the climate zones would shift purely as a result of human emissions.

    If they could establish that it is substantial in relation to natural climate zone shifting then they would be onto something but they must know it is infinitesimal otherwise they would indeed focus on that instead of ignoring the Gas Laws and resorting to the untenable proposition that radiative physics can ignore the Gas Laws.

    Some AGW proponents and even the models do recognise that poleward shifting of climate zones would occur in a warmer world but they fail to acknowledge that shifting of 1000 miles or more occurs naturally between times such as the MWP and LIA and they are resisting the observation that the earlier poleward shifting stopped around 2000 and may now be equatorward shifting despite continuing rises in atmospheric CO2.

    The fact is that the poleward shifting is a reflection of faster energy loss from surface to space. It is the climate zone shifting that prevents global surface warming.

    The surface warming in the mid latitudes from more warm equatorial air moving across is offset by colder poles as the more zonal circulation cuts the poles off from inflowing warm air so the poles get colder.

    When the mid latitudes cool the poles get warmer because more meridional jets allow more air to flow in and out of the poles.

    AGW proponents must start to realise that the lack of poleward shifting since 2000 despite the increasing CO2 puts a disconnect into the suggested causal relationship between CO2 increases and global surface temperature.

    Pre 2000 I saw a TV documentary stating clearly that the poleward shifting was due to CO2, permanent and all our fault.

    What about an update ?

    All the news now is about the climate consequences of more meridional / equatorward jets yet CO2 is still rising (for the time being).

    And the more meridional jets are being more and more attributed to the quieter sun.

    All the dots are there. Just join them up 🙂

  37. Wayne Job says:

    I seem to have read of late that all planets have been warming, not just this moon, thus it would be reasonable to assume that a common denominator is causing the warming. Your guess is as good as mine. I would also suspect that they will be cooling soon.