From the University of British Columbia:
Compared to its celestial neighbors Venus and Mars, Earth is a pretty habitable place. So how did we get so lucky? A new study sheds light on the improbable evolutionary path that enabled Earth to sustain life.
The research, published this week in Nature Geoscience, suggests that Earth’s first crust, which was rich in radioactive heat-producing elements such as uranium and potassium, was torn from the planet and lost to space when asteroids bombarded the planet early in its history. This phenomenon, known as impact erosion, helps explain a landmark discovery made over a decade ago about the Earth’s composition.
Researchers with the University of British Columbia and University of California, Santa Barbara say that the early loss of these two elements ultimately determined the evolution of Earth’s plate tectonics, magnetic field and climate.
“The events that define the early formation and bulk composition of Earth govern, in part, the subsequent tectonic, magnetic and climatic histories of our planet, all of which have to work together to create the Earth in which we live,” said Mark Jellinek, a professor in the Department of Earth, Ocean & Atmospheric Sciences at UBC. “It’s these events that potentially differentiate Earth from other planets.”
On Earth, shifting tectonic plates cause regular overturning of Earth’s surface, which steadily cools the underlying mantle, maintains the planet’s strong magnetic field and stimulates volcanic activity. Erupting volcanoes release greenhouse gases from deep inside the planet and regular eruptions help to maintain the habitable climate that distinguishes Earth from all other rocky planets.
Venus is the most similar planet to Earth in terms of size, mass, density, gravity and composition. While Earth has had a stable and habitable climate over geological time, Venus is in a climate catastrophe with a thick carbon dioxide atmosphere and surface temperatures reaching about 470 C. In this study, Jellinek and Matt Jackson, an associate professor at the University of California, explain why the two planets could have evolved so differently.
“Earth could have easily ended up like present day Venus,” said Jellinek. “A key difference that can tip the balance, however, may be differing extents of impact erosion.”
With less impact erosion, Venus would cool episodically with catastrophic swings in the intensity of volcanic activity driving dramatic and billion-year-long swings in climate.
“We played out this impact erosion story forward in time and we were able to show that the effect of the conditions governing the initial composition of a planet can have profound consequences for its evolution. It’s a very special set of circumstances that make Earth.”
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This article drew lots of excellent comments. Earth is at an orbit where substantial amounts or water are present and temperatures permit all three phases of water to exist simultaneously. This produces a very stable climate regime where the solvent properties of water allow all sorts of chemistry to take place. As for CO2, that was taken care of by the appearance of critters in the ocean that could consume it. And of course more critters appeared to consume the oxygen they produced, namely, us. As for Venus, close to the sun, it has a massive atmosphere which convects just like earth’s so that the high surface pressure along with the shorter orbital radius produces high surface temperatures, too high for liquid water to exist. These simple facts need to be taken into consideration before greenhouse gasses, plate tectonics, and impact erosion are even thought of. In fact, that Venus’ atmosphere follows the same laws of thermodynamics as on earth is powerful evidence that the Climate Consensus and its fixation on radiative models is barking up the wrong tree.
Not quite. CO2 was starting to be removed from the atmosphere long before the emergence of life by liquid water acting as a catalyst to convert CO2 into limestone.
Well said, pochas.
There are many here and elsewhere who are coming to realise that not only are the alarmists wrong in denying the effect of atmospheric mass in causing the so called greenhouse effect but also a number of sceptics are wrong too including the well respected rgbatduke, our esteemed host plus the entertaining and usually informative Willis Eschenbach.
Convection adjusts to counter any radiative imbalances so as to maintain the hydrostatic balance of the atmosphere and no increase in surface temperature ensues unless one changes TOA insolation or global albedo assuming atmospheric mass and the strength of the gravitational field remain the same.
http://www.public.asu.edu/~hhuang38/mae578_lecture_06.pdf
Such was basic high school physics 50 years ago.
An atmosphere will only convect if it is heated from below and only 3% of impinging solar energy reportedly reaches its surface . Thus there would be almost no convection . If there is , it indicates internal heating even if the gravitational-thermal trade-off notion is true .
An atmosphere will convect through its entire depth as a result of density differentials arising in the horizontal plane at any height.
Rising or falling which is initiated at any point in the vertical column forces a chain reaction through the entire column.
This is why my core interest is in constructing the executable notation to succinctly express these relationships and be able to play with them .
You won’t get bottom to top convection in a planar top heated fluid . Venus’s rotation is so slow that there’s not much Coriolis effect . The extreme difference in diurnal insolation would be a driver , but that’s somewhat a different phenomenon .
The is a great deal of food for thought in this discussion , but I have no more time for it now .
I think it is most significant that the science of Venus’s extremes is so unsettled . If we can’t with well winnowed quantitative theory explain Venus’s 225% ratio of surface temperature to gray body temperature , what chance do we have of understanding Earth’s 3% , much less the 0.3% total variation this whole statist useful brouhaha is over .
An atmosphere is never a planar top heated fluid because density declines with height.
Insolation will always penetrate deeply enough through the low density upper layers to set up convective overturning through the entire vertical column.
That is why Venus has convection despite such a small proportion of insolation reaching the surface.
Bob,
Google “images venus” and click “more images.” Convection bands are clearly evident on many images that show the outer atmosphere, even though the atmosphere is heated from the top as you say. Convection occurs when gas heated at the equator advects toward the poles where it cools, densifies, and sinks. Heat of compression raises its temperature as it descends. Finally the hot gas migrates back to the equator to complete the cycle. Actually, the circulation is probably divided into cells as it is on earth.
Mike McMillan said:
“Still confused about the adiabatic lapse rate I see.
Maintained by gravity. An upward moving gas molecule loses speed, and thus temperature, to gravity. A downward moving molecule gains speed and thus temperature.”
That is only part of what happens.
In rising, gas molecules move apart and, as they do so, work is done against the force of gravity which seeks to pull them together into a smaller volume closer to the centre of gravity.
It is the moving apart that creates the bulk of the PE acquired by expanding gases at he expense of KE. That PE is additional to the PE acquired by simple uplift from the surface.
Less dense gases are cooler (vibrating less) and more dense gases are warmer (vibrating more) which is quite unlike solids and liquids, hence the need for The Gas Laws. At all times the gas molecules carry the same total energy but that energy transforms between KE (heat) and PE (not heat) in ascent/expansion and back again in descent/contraction.
Once one understands that concept it all falls into place such that radiative gases are not needed to explain surface temperatures higher then a straightforward S-B calculated radiative only energy exchange would suggest.
Stephen 8:32am: “..radiative gases are not needed..”
Who would you say wrote: “I do subscribe to IR emanating from each level of the atmosphere according to its temperature at that height”? Read the full context and consider that this energy is not destroyed Stephen. Nor does testing show evaporation and convection speed up to counter or compensate for this “emanating” energy. Consider also the water temperature was modulated by modulating the “emanating” energy, shielded and unshielded.
http://www.drroyspencer.com/2015/06/can-infrared-radiation-warm-a-water-body-part-ii/#comment-194491
Energy is not destroyed or created. It is simply transformed to an fro between KE (heat) which does release IR and PE (not heat) which does not release IR.
The proportion of PE relative to KE at any given height determines the amount of IR that will be released because that determines the temperature at that height.
Stephen 10:10am: Good, energy is not destroyed so Stephen gets some of the “emanated” energy entered the water.
Ideally also KE+PE yes, but nature is not ideal, not as tidy in experiments, some KE is transformed to radiation also, to and fro, not just PE. Testing shows no speed up of evaporation and/or convection to counter the “emanating” energy of the cirrus clouds after 1:30am, the water temperature is affected by their added “emanating” energy as this energy is not destroyed.
By the way Stephen, doesn’t it bother you that I can add&subtract PE to your ideal system merely by changing the arbitrary ref. level for PE? Could that be why Venus is so warm at the surface, nature merely changed the ref. level for PE over there? It is closer to the sun, atm. PE must be way down compared to earth in higher orbit.
All this about late heavy bombardments and the formation of the moon from a collision ignores one fact, the oldest rocks on earth, some 4.35 billion years old, show that they were all formed in the presence of liquid water. Would not a bombardment that threw off the crust, or a glancing blow that tore off the moon, also tear off that water and/or those oldest rocks that were formed in the presence of it?
If there was a late heavy bombardment that added the water, it would have to have added that before 4.35 billion years ago.
The idea that a late heavy bombardment is where our water came from came from the exact composition of that water matching one, and only one, comet from the Kuiper belt. However, now we have landed a craft on another comet from way out there, and discovered that its composition does not match that of the other nor of the earths water, this theory is discredited.
Any theory must therefor match the data of these earliest rocks, and the water completely covering the earth at that time, and preserve that water and those rocks through any bombardment or glancing moon causing blow that may happen, or those must have happened before 4.35 billion years ago, leaving an earth that, when it cooled, was completely covered in water.
That Venus is closer to the Sun and has an atmosphere two orders of magnitude more massive than Earth’s seems to be irrelevant in the minds of those seeking attention for this “evolutionary” theory of climate.
1sky1
Yes, it is weird.
I’ve spent the past several years arguing with so called sceptics who think an atmosphere must become isothermal in the absence of GHGs. They think that radiation from those GHGs is what causes the decline in temperature with height which is simply daft. Even Roy Spencer thinks that to be the case.
The decline in density with height occurs because as one moves up and away from the surface of a sphere the space available for the gases to expand into increases exponentially.
By virtue of three dimensional geometry an exponential increase in available space translates into a linear decline in density with height.
As the gas molecules move apart they vibrate less because their kinetic energy is used to power the process of moving apart against the force of gravity which is trying to pull them together into a smaller, lower volume towards the centre of gravity. Reduced vibration manifests itself as cooling and the visible sign of that cooling is the lapse rate slope.
You cannot stop convective overturning when a decline in density with height develops within an atmosphere held off a surface in hydrostatic balance against the force of gravity.
All one then needs is uneven surface heating which is inevitable around a sphere.
It is that convective overturning that pushes gas molecules up and away from the surface in the first place.
Kinetic energy held at the surface and which is engaged in maintaining hydrostatic balance ceases to be available for radiation to space because it is taken up in ascending columns via conduction and convection as fast as it returns in descending columns.
It is locked into the system and cannot radiate out to space past the mass of the atmosphere.
Thus the surface temperature increases as a consequence of atmospheric mass.
Old science that has been forgotten, not taught or deliberately ignored.
Stephen 11:49am: “Thus the surface temperature increases as a consequence of atmospheric mass.”
Because all mass radiates, at all times, all temperatures, all frequencies, depending on its mass extinction coefficient & mass mixing ratio, partial pressure of the particular specie. The water temperature under test was thus affected due radiation from cirrus clouds at 1:30am; evaporation & convection did not have the offsetting effect you claim.
Add more atm. mass, get more radiation as on Venus, less mass, less radiation as on Mars as in:
“I do subscribe to IR emanating from each level of the atmosphere according to its temperature at that height”
Radiation at a surface beneath an atmosphere (beyond that representing the equilibrium state of energy in equalling energy out) is merely a consequence of temperature caused by the interaction between mass and insolation. That temperature is highest where density is greatest because the greater the density the greater the proportion of insolation that is taken up by conduction and convection.
That means the temperature (with its IR) is highest at the surface and declines with height at a rate determined by the decline in density.
The radiative capability of the atmospheric mass is not causing the elevated temperature. The elevated temperature is a consequence of mass conducting and convecting and the IR present at the surface is a consequence of those non radiative processes.
It would all happen even if the radiative capability of the atmosphere were zero.
Diagram 3 in this article is especially pertinent:
http://hockeyschtick.blogspot.co.uk/2015/07/erasing-agw-how-convection-responds-to.html
Stephen 1:10pm: “The radiative capability of the atmospheric mass is not causing the elevated temperature.”
In the real world test, the added IR radiation from the cirrus showing up at 1:30am modulated the water temperature Stephen just as it does the 33K, and even the shield modulated the DW IR. While evaporation and convection undoubtedly had an effect, it was negligible & not immediate, the added IR being at speed of light was immediate. Dr. Spencer constructed a decent cloud detector, as did NOAA ESRL with same confirming results – on the same all mass radiates theory.
“..the IR present at the surface is a consequence of those non radiative processes.”
True but as you repeatedly write their energy exactly balances up and down so they don’t change median T over multiple annual periods yet surface T median does change due a surface atmospheric window (Venus surface has no true windows at wavelengths above 3 microns), and “I do subscribe to IR emanating from each level of the atmosphere according to its temperature at that height”.
“It would all happen even if the radiative capability of the atmosphere were zero.”
In which case so would the sun’s be zero, it would be mighty dark around here, no stars in the sky. If we were here, our campfires would look weird, but we might guess the moon is there based on tides et. al., and a space probe (wired as no radio) running into something.
Trick,
Variations are due to albedo changes altering the proportion of insolation that can be absorbed.
The radiative capability of an atmosphere of pure Nitrogen would be near enough zero as makes no difference for the purpose of my illustration. It does not follow that a sun made of other more radiative materials would also be near enough zero as makes no difference.
You seem to be setting out to obscure the basic point so as to confuse readers and pretend to be of superior intellect.
It is not disputed that all mass radiates to some extent. The point is that radiative capability is not the cause of the greenhouse effect whereas conduction and convection is.
Stephen 2:17pm – I make no assumption on intellect. Only the written word is evident here.
Albedo is reflected SW radiation not convection/conduction or evaporation Stephen, so the IR present at the surface does vary with that radiation modulation in addition to DW IR due clouds. Did the albedo change in Dr. Spencer’s experiment? Did evaporation/conduction change appreciably & immediately? No to both Stephen, the DW IR added from the cirrus changed the water temperature near earth surface measurably/immediately in the same way it affects the 33K. You can see the confirming effects in NOAA ESRL plots.
An easy energy balance including conduction/convection, evaporation & radiation can quickly compute the measured median ~33K and shows 0K on median T from conduction/convection multiple annual averages. So your task is to show a similar eqn. using just mass, insolation, gravity.
Any surface warming beneath stratiform cloud cover is due to a reduction in convection beneath the cloud and not a warming effect from downward radiation.
Additionally, clouds float above higher humidity which suppresses evaporaton from any water surface beneath them so that the water surface warms.
You are constantly introducing irrelevant special circumstances because you do not wish either yourself or readers to understand the reality.
HS has given equations relating to the US Standard Atmosphere which do show that mass, insolation and gravity are all one needs to establish the surface temperature and the lapse rate slope.
It applies on multiple planets with atmospheres with no term required for the radiative characteristics of constituent molecules.
Trick (replying to Stephen)
No, the -33 deg C ONLY works on the flat-earth simplified single-plane equilibrium radiation model favored by Trenberth’s approximations…
The real world (a sphere, last time we saw photo’s of earth) irradiated over an elliptical orbit while rotating every 24 hours at a 23.46 degree angle to the elliptical plane) does NOT come into any sort of -33 degree (not +14 degree, not any other constant temperature) because, in part) the most radiation received is between +45 and -45 degrees latitude, and the most energy radiated is at the regions of the highest temperatures. NO PLACE – even in the vacuum around the moon) exhibits the simplifications you seek.
Now, do that “simplified” radiation model for the actual moon you claim is so easy. Show me the actual full month cycles of the moon’s surface (1/2 meter deep) at each 10 degree band from pole to pole.
Roger 4:06pm: “..33 deg C ONLY works..”
Glad you agree the simplification does work Roger, it is at best a good analog do not stretch it. Stephen has not been able to improve on it with only mass, insolation and gravity.
“..do that “simplified” radiation model for the actual moon..”
Unfortunately the surface of the moon has significance diffraction from the powder, can’t ignore diffraction as was done by Planck, so not even straight Planck radiation is going to work on our moon, it is a toughie; I have seen no simplification that works on the powder. Going to have to grind it out or go set a thermometer field in place equiv. to GCN. Or better.
Actually the simplification gets more complicated on Venus too as the optical depth is so thick multiple layers are necessary not just the one layer that works so well on earth, but there are those that have done it the hard way, get results pretty close to ~730K from 1st principles for surface T and the upward profile after enough iterations.
Stephen – low stratiform clouds form from warm, moist upward convection. At any rate, the ~288K/33K are from global multiple annual periods including all the stratiform nature has to offer. The high ones in Dr. Spencer’s test are not a special circumstance and illustrate real world testing. Any other cloud type would have served the same purpose.
The US Standard 1976 atm. surface 288K was voted on by a committee as well as the profile which averaged mid-tropics testing by the thousands which include the radiation effects, there may be no real natural atm. anywhere showing the same profile, if there is, see the defn. of coincidence. And it has since changed! How could that be if only mass, insolation, gravity are involved?
Stratifirm clouds do not involve convection. They arise from temperature and humidity differences between layers. They are a result of horizontal advection not vertical convection.
Surface warming beneath clouds is a consequence of reduced upward convection (above land) and/or reduced evaporation above water) and NOT downward radiation. It is a non radiative process.
Roy Spencer’s cirrus clouds are at a point along the lapse rate slope where the temperatures are very low and IR coming downward is negligible. Cirrus clouds do not warm surfaces by radiating IR at them.
Roy is a whiz in his speciality but knows little basic meteorology, a common problem these days.
The Standard Atmosphere is a worldwide average and it works to a high degree of accuracy sufficient for aeronautics and rocketry. It may well be that the real world always shows something different at any given location or time but that is because the air is highly mobile and does not detract from the practical and empirical success of the numbers used.
It has not been ‘changed’, merely refined as more measurements accumulate. It is getting ever closer to the actual thermal profile derived from equations involving only mass, gravity and insolation. Radiation not needed.
Stephen 1:09am: “Cirrus clouds do not warm surfaces by radiating IR at them.”
Dr. Spencer’s test results show real world nature does not agree with your assertion. NOAA ESRL confirms Dr. Spencer’s results with daily records at its observing stations, detecting passing clouds with same results. To get meteorology right, according to test & instrumental observation, Stephen, you will have to add effects of radiation to your repertoire.
1:15am: “The Standard Atmosphere is a worldwide average…it has not been changed.”
Not worldwide only around mid-tropics, and US Standard Atm. was changed, updated by committee vote in 1993 to include the avg. changes nature made in the interim. It is not “derived” from eqn.s involving only mass, insolation and gravity, the numbers are from averaging huge amount of test flights in and around the mid-tropics including all of nature’s radiation therein.
Trick claims 1976 US Std Atmosphere “is not “derived” from eqn.s involving only mass, insolation and gravity, the numbers are from averaging huge amount of test flights in and around the mid-tropics including all of nature’s radiation therein.”
False, the 1976 US Std Atmosphere IS derived from basic physical chemistry & physics of molecular mass/gravity/pressure/density. The complete mathematical derivation & mathematical model is described in 50 pages of the 1976 US Std Atm technical description here:
http://hockeyschtick.blogspot.com/2014/12/why-us-standard-atmosphere-model.html
And their model does not use one single radiative transfer calculation whatsoever. AFTER developing the mathematical model, the model was then verified with millions of rocket, radiosonde, & flight observations.
Hockey , you and Stephen have opened my eyes to the very profound relationship between temperature and gravity . Alan Guth’s ( not original with him ) notion of gravity as being negative energy simplifies the thinking for me . So what is balanced at the effective radiative surface is
gravity + KineticEnergyand that is the quantity the divergence theorem holds constant .I’ve said since first getting diverted into this slough that calculating the mean temperature of a planet was more akin to calculating the temperature of a volume of gas thru gas laws rather than getting involved with the details of the internal eddies . Whatever convection there may or may not be doesn’t even enter into this constraint .
I’m glad all I did in my Heartland talk is show the quantitative absurdity of Hansen’s claim that Venus’s surface temperature was due to its spectrum rather than claim I knew the cause . I look forward to implementing and confirming your computations . I had been aiming at mapping the cosine function over the hemisphere and adding simple thermal conductance and radius as the next couple of expressions to implement ( in 4th.CoSy ) , but this is simply scalar and clearly the most important additional parameter .
BTW : my annual CoSy MidSummer Mountain Mela is next Saturday , August 1 . I invite anyone along the Front Range interested in this stuff enough to be reading this — and I know we are overrepresented here .
Damn , missed a closing .
A closing “” . Did that do it ?
( What ever value there is in having posts be archival is not a justification for no ability to preview or modify at least for a short period . )
Oops, corrected tag.
HS 11:43am: The US Standard Atmosphere, in the foreword, communicates and I quote verbatim skipping some uninformative classification detail: “The definition of the lowest 50km was recommended as the standard for international adoption by the International Standards Organization (ISO) cognizant committee…..It was approved by the ISO Member Bodies in September 1973 as the ISO Standard Atmosphere (ISO 1973).”
The 1976 starting z=0.0m temperature 288.156K is based on two international agreements (15C from 1924 !! & unchanged from that date) & profile avg. 6.5K/km is the product of a committee recommendation & approval, not nature, the Standard Atm. is “a hypothetical vertical distribution of atmospheric temperature, pressure and density…roughly representative of year round midlatitude conditions.”
Though the committee was guided by the tests and the science, it is not a natural atm. that can be studied for climate research or to draw reliable climactic conclusions, since it is hypothetical, thus you & Stephen should use actual soundings and basic/advanced science from measurement, analysis and test data which are intended for climate related conclusions. Commonly available in relative modern text books, especially those devoted to radiation (and RTM!).
The ISO standard typical uses: “pressure altimeter calibration, aircraft performance calculations, aircraft and rocket design, ballistic tables, and meteorological diagrams. The air is assumed to obey the perfect gas law and hydrostatic equation…”
Noticeably absent is an intended usage to draw real world (non-ideal) climate related conclusions.
As a hypothetical, the US Standard Atmosphere is derived from ideal non-real world eqn.s and “is not “derived” from eqn.s involving only mass, insolation and gravity, the numbers are from averaging huge amount of test flights in and around the mid-tropics including all of nature’s radiation therein.”
For instance, beyond mass, gravity, and insolation there are “diffusion coefficients”, molecular weights, number density of individual species, Maxwellian velocity distributions discussed and many more considerations. It is a good read. You can learn a lot. The various eqn.s for Tm came from expressions in the ARDC Model Atmosphere 1956 (Minzner and Ripley), as revised, from rocket and satellite data, a good read, See Fig. 2 for the curve fit. This when Venus data was a decade away.
“..their model does not use one single radiative transfer calculation.”
Agreed, ISO standard is not of RTM real world accuracy (meaning RTM used for analyzing real earth profiles close to observed as can be done for Venus), ISO Standard is only ideal & hypothetical committee vote after curve fitting.
“I’ve spent the past several years arguing with so called sceptics who think an atmosphere must become isothermal in the absence of GHGs. They think that radiation from those GHGs is what causes the decline in temperature with height which is simply daft. Even Roy Spencer thinks that to be the case.”
Yup, me too.
Easiest math proof that a pure N2 atmosphere would have an even greater GHE/tropospheric temperature gradient than the current Earth atmosphere:
http://hockeyschtick.blogspot.com/search?q=N2+Boltzmann+distribution
The decline in density with height occurs because as one moves up and away from the surface of a sphere the space available for the gases to expand into increases exponentially.
Shouldn’t that be quadratically?
As the gas molecules move apart they vibrate less because their kinetic energy is used to power the process of moving apart against the force of gravity which is trying to pull them together into a smaller, lower volume towards the centre of gravity. Reduced vibration manifests itself as cooling and the visible sign of that cooling is the lapse rate slope.
The translational kinetic energy is what is used to move them apart, not the vibrational energy. If the molecule is vibrationally excited and possesses a dipole then it will lose the excess vibrational energy by radiation.
Phil,
I’ll check both points but if you are right and my terminology is not correct the conclusions are the same.
There is a linear decline in temperature with height whether the decline in density is quadratic or exponential.
Molecules cool and move about less as they move apart whether it is a loss of translational or vibrational energy. Can vibrational energy decline by means other than loss of a photon such as by conduction to another molecule that has lost translational energy ?
If so, the distinction is not relevant.
HS 11:43am: The US Standard Atmosphere, in the foreword, communicates and I quote verbatim skipping some uninformative classification detail: “The definition of the lowest 50km was recommended as the standard for international adoption by the International Standards Organization (ISO) cognizant committee…..It was approved by the ISO Member Bodies in September 1973 as the ISO Standard Atmosphere (ISO 1973).”
The 1976 starting z=0.0m temperature 288.156K is based on two international agreements (15C from 1924 !! & unchanged from that date) & troposphere profile avg. 6.5K/km is the product of a committee recommendation & approval, not nature, the Standard Atm. is “a hypothetical vertical distribution of atmospheric temperature, pressure and density…roughly representative of year round midlatitude conditions.”
Though the committee was guided by the tests and the science, it is not a natural atm. that can be studied for climate research or to draw reliable climactic conclusions, since it is hypothetical, thus you & Stephen should use actual soundings and basic/advanced science from measurement, analysis and test data which are intended for climate related conclusions. Commonly available in related modern text books, especially those devoted to radiation (and RTM!).
The ISO standard typical uses: “pressure altimeter calibration, aircraft performance calculations, aircraft and rocket design, ballistic tables, and meteorological diagrams. The air is assumed to obey the perfect gas law and hydrostatic equation…”
Noticeably absent is an intended usage to draw real world (non-ideal) climate related conclusions.
As a hypothetical, the US Standard Atmosphere is derived from ideal non-real world eqn.s and “is not “derived” from eqn.s involving only mass, insolation and gravity, the numbers are from averaging huge amount of test flights in and around the mid-tropics including all of nature’s radiation therein.”
For instance, beyond mass, gravity, and insolation there are “diffusion coefficients”, molecular weights, number density of individual species, Maxwellian velocity distributions discussed and many more considerations. It is a good read. You can learn a lot. The various eqn.s for Tm came from expressions in the ARDC Model Atmosphere 1956 (Minzner and Ripley), as revised, from rocket and satellite data, a good read, See Fig. 2 for the curve fit. This when Venus data was a decade away.
“..their model does not use one single radiative transfer calculation.”
Agreed, ISO standard is not of RTM real world accuracy (meaning RTM used for analyzing real non-hypothetical earth T(z) profiles close to observed as can be done for Venus), ISO Standard is only ideal & hypothetical committee vote after some ideal eqn.s and curve fitting.
Nonsense.
Well now, Since New Horizons finally reconnected me WI-FI with Yuggoth, that’s PLUTO to you denizen’s of Erf, we can answer your ape like grunts with the wisdom of the Fungi from Yuggoth.
The Reasons you are not citizens of Venus, is because the Elder Things settled on Erf, and grew your ancient ancestors in a vat, in that frozen waste you call the Antarctic.
Simples.
By the way, it was a bloody nuisance playing hide and seek with that probe, spent ages looking from an empty hidy hole, Pluto isn’t exactly large you know.
Your Over lord superiors have spoken,…wait which button do I push?,…that one?, no? that one!,…well that’s daft who puts a self destruct button next to an off switch,…
Bear in mind the gods don’t really care what we believe. But we do keep them smiling. 🙂
This has been an interesting thread.
For any lurkers like myself a few pics of the surface of Venus may be interesting:
http://cseligman.com/text/planets/venus.htm
wayne,
Consider a rocky planet with no atmsphere. Then volcanic activity releases a bubble of gas.
That gas will expand without pushing against other gas molecules.
According to your scenario it will not cool during expansion because there are no other gas molecules for it to push against.
In reality it will expand againsty the pull of gravity which constantly tries to draw the gases back towards the centrre of gravity.
Work is done against gravity and the gases cool during expansion as per The Gas Laws.
Will.
You contend that air suspended off the ground against gravity in hydrostatic balance has no weight.
How, then, do you account for pressure at the surface which falls when the surface is overlain by warmer lighter rising air and rises when the surface is overlain by colder denser falling air?
Stephen Wilde says, July 26, 2015 at 3:23 am:
“Consider a rocky planet with no atmsphere. Then volcanic activity releases a bubble of gas.
That gas will expand without pushing against other gas molecules.
According to your scenario it will not cool during expansion because there are no other gas molecules for it to push against.”
Stephen, this is not “according to [wayne’s] scenario” (is he even on this thread?). It’s according to science, meteorology, atmospheric physics, common knowledge among people who’ve taken even a single course on thermodynamics.
Of course the gas won’t cool during expansion when it has nothing to push against. It’s called “free (or isothermal) expansion” and happens without a change in T. Just look it up. The opposite is “adiabatic expansion”, where the air rising is constrained by surrounding air and thus have to push it to the side (against a certain external pressure) in order to expand, thus DOING WORK ON THE SURROUNDING AIR, losing internal energy in the process, thus cooling. You can read about it for instance here (or in ANY learned text on the subject; if you want more sources, I’ll be happy to provide some, or you can just google “adiabatic process”):
http://eesc.columbia.edu/courses/ees/climate/lectures/atm_phys.html
From the link (under the heading “The first law of thermodynamics and adiabatic expansion:”):
“In reality it will expand againsty the pull of gravity (…)”
What does this even mean? Expand against the pull of gravity!? The bubble of gas will expand in all directions, Stephen. Up, down and to the sides. Spontaneously. Because there’s nothing stopping it from doing so. The gas will simply dissipate until it’s no longer a gas, simply according to the various trajectories of the individual gas molecules, the molecules eventually drawn back to the surface by gravity, if, before this happens, they don’t manage to escape into space. This is how the exosphere is maintained on different moons and asteroids in the solar system. An exoshpere is not really an atmosphere in its proper sense, because the gas molecules are spread so far apart that they hardly, if at all, interact.
Aaarrgh! Thanks, wordpress!
Kristian,
I meant to post on another thread elsewhere but no matter since you make the same error as the said wayne.
The example of isothermal expansion is limited to a parcel of gas which expands equally in all directions without altering its height. That assumes no solid surface beneath it restricting downward expansion.
A bubble of warm gas exiting from the ground and rising upwards against gravity whilst expanding as it does so is a very different scenario.
The gas leaving the ground will expand and cool as its molecules move upward and apart even without any surrounding molecules for it to do work against. There is no container wall for it to do work against.
In that case ‘the surroundings’ are the ambient gravitational field which is seeking to pull the gases back down towards the surface.
The quote you found is not applicable to the latter scenario and it is the latter scenario that applies to atmospheres around planets as opposed to free floating parcels that do not change height.
Stephen, you say:
“The gas leaving the ground will expand and cool as its molecules move upward and apart even without any surrounding molecules for it to do work against. There is no container wall for it to do work against.”
No, Stephen. It doesn’t magically come true just because you say it’s so, just because that’s how you picture it.
All you do is make up your own physical principles as you go along and state them as truth. You’re getting nowhere with such an approach. You will convince some people who don’t know this subject. The people who do know it, however, will laugh, shake their heads or just ignore. I’m trying to make you open your eyes and step out of your bubble. You need to pick up a book soon and start reading. You can never expect to be taken seriously before you do and stop promoting your self-invented nonsense physics. What you say goes squarely against the entire fields of thermodynamics, meteorology and atmospheric physics. You have to just realise that. Wake up.
Free, isothermal expansion of a gas happens in a vacuum. Gravity or no gravity. Gravity doesn’t cool the gas. If there’s no surrounding air for the gas to do work on, it will not cool. Everyone who has read just a little bit about these topics knows this. And that’s why we don’t know what to do with you. Because you simply won’t take that step back and go ‘Hmmm, maybe I should pick up that book’, no matter how many times we tell you (and show you) how fundamentally wrong you are. We lead you to the water. It’s there, right in front of you. Just drink. (It’s there. In black and white.) But you won’t. You just go ‘Oooh, look over there!’ And you’re off, as if nothing had happened. And everything starts all over again … It’s an impressive ability that you share with Doug.
You say: “The quote you found is not applicable to the latter scenario and it is the latter scenario that applies to atmospheres around planets as opposed to free floating parcels that do not change height.”
!!!!! The quote I found SPECIFICALLY addresses what happens in the atmosphere, Stephen. And I’ve shown you tens of similar ones before. They all say the same thing. It’s everywhere. It’s one of the first things you learn in this field. The fundamental connection between the 1st Law of Thermodynamics and the adiabatic process is legendary. This knowledge, these principles, go back to the days of Carnot and Clausius and their heat engines. It is work against surroundings, against external pressure, Stephen. NOT GRAVITY!!!!
Q = 0, so ΔU = -W. Pressure/volume work, Stephen. Ideal gas law. 1st Law of Thermodynamics. Adiabatic process. Look it up …!
Your obstinate refusal to acknowledge these simple (and totally uncontroversial) physical concepts, rather insisting that everyone else is simply wrong and misguided and only you (and Doug) are right, we all somehow missed it, and only you see it, frankly speaks volumes all by itself.
But it’s sad to behold.
I don’t see what this raging quibble is over . I doubt if Stephen has any real disagreement about gas laws sans the gravity parameter .
Stephen’s point , and Hockey’s and , I think Huffman’s is that gravitational energy ( or negative energy ) must be considered in temperature balance equations . I just never thought of it as having a significant static effect . But it’s effect is clearly rather simply and precisely computable .
Odd as it seems to me , the pressure and temperature lower in a gravitational field must be greater to balance a radiant temperature in essentially a 0 gravitational field .
Bob,
This “raging quibble” is over the adiabatic process and how it works in our atmosphere. Stephen thinks he’s come up with something that no one else in thermodynamics (all the way from Carnot and Clausius), in meteorology or in atmospheric physics, has ever realised, that adiabatic cooling and heating really works simply by a conversion back and forth between molecular KE and (what is perceived as) molecular PE as the air rises and falls in the atmospheric column. This is of course nonsense. And it is common knowledge in these fields that it is.
Stephen is simply mixing up the mechanical movement of bulk air up and down within the tropospheric column (where there is conversion going on between KE and PE, only bulk (centre of mass) KE and PE, not affecting the air temperature at all) with the adiabatic process, which only involves the expansion and contraction of the air as it moves up and down and thus faces a reduced, then increased, external air pressure. The adiabatic process affects directly the temperature of the air, because it pertains to its internal (microscopic/molecular, disordered) energy.
This is elementary stuff, and it annoys people who know these things, who have studied them thoroughly at university level for years, constantly having to wade through Stephen Wilde’s misguided ramblings on these issues that he clearly knows nothing about, just wild (!), self-invented physics that he does his best to push at every opportunity on whoever might pass by.
Bob, you say: “Stephen’s point , and Hockey’s and , I think Huffman’s is that gravitational energy ( or negative energy ) must be considered in temperature balance equations . I just never thought of it as having a significant static effect . But it’s effect is clearly rather simply and precisely computable .”
Hockeyschtick and Huffman are both wrong. They don’t see the forest for the trees. Gravity works together with the mass of an atmosphere to create a pressure and a density gradient, fine. However, these two parallel gradients can both be compressed and stretched, and the surface starting point of the density gradient can likewise be moved back and forth along the x-axis. How? Through a change in temperature, creating a change in ‘internal (or thermal) pressure’. This will not affect the adiabatic lapse rate, but it will affect the altitude of the so-called ‘average atmospheric level of upward radiation’, better known as the ERL. Same with mass and/or gravity. Increase the atmospheric mass (or planetary gravity) and the ERL is forced upward, away from the surface. This in turn will cause a rise in surface temperature.
HS claims that the ERL is simply located at the atmospheric ‘centre of mass’. It’s not. On Earth (and Titan) it’s close. Not quite there, but in the general ballpark. That’s because these two bodies happen to have ‘moderately’ thick atmospheres, and thus their ERL is forced somewhat off the surface. On Mars, the atmosphere is extremely thin and light, so thin that the ERL is actually to be found on the surface, below the entire mass of the atmosphere. At the other end of the spectrum, Venus’s atmosphere is extremely massive (heavy and dense), which means the ERL is forced 60-65 km off the ground, to the actual tropopause cloud layer, above most of the atmospheric mass.
Kristian said:
“Free, isothermal expansion of a gas happens in a vacuum. Gravity or no gravity. Gravity doesn’t cool the gas. If there’s no surrounding air for the gas to do work on, it will not cool.”
Movement away from a centre of gravity by way of raising height above a body of mass large enough to generate a gravitational field allows expansion that results in cooling as per The Gas Laws.
Expansion without movement away from a centre of gravity does not.
My example does state that the bubble of gas emanating from the rocky surface is warmer than the temperature of the surrounding vacuum otherwise it would not rise.
“It is work against surroundings, against external pressure, Stephen. NOT GRAVITY!!!!”
There is no external pressure when there is no gravitational field. Gravity imparts weight and thus pressure to mass. Expansion without changing position relative to a centre of gravity involves no change in external pressure and thus no change in temperature.
Kristian is so emotionally committed to the false impression that cooling in uplift is caused by rising air passing heat energy to surrounding moecules by doing work on them that he cannot accept that the work being done in adiabatic uplift is being done against the gravitational field and not against the surrounding molecules.
Even in the quote he refers to the reduction in outside pressure comes before the expansion and the walls of the parcel are therefore moving outward at the same rate as the molecules in the parcel so that the walls are exerting zero resistance against the outward moving molecules.
Zero resistance from the expanding walls means trhat no work is being done on those walls. The work being done is being done against the gravitational field which has been weakened so as to reduce the external pressure in the first place.
I am expressing the established science on this point. Kristian’s idea that a bubble of warm gas rising off the surface of a planet that previously had no atmosphere will not cool as it expands is bizarre and clearly contrary to The Gas Laws.
Kristian’s quote says:
“When a force is moving an object over a given distance it does work. Thus the expanding air parcel does work on its surroundings. ”
That does not say that the surroundings are the surrounding molecules. The surroundings against which work is being done is the ambient gravitational field when the expansion follows an initial reduction in external pressure. It is the movement across a distance that matters whether there are other molecules in the way or not. If there were no initial reduction in external pressure prior to the expansion then in that case the work would indeed have to be done against surroiunding molecules but that would then be a diabatic process with heat moving out from the parcel to those surrounding molecules via the work done.
If there is no gravitational field or if the expansion all occurs with no change in height then there is no change in temperature despite the expansion because then no work is done against either the ambient gravitational field or against surrounding molecules.
For expansion with no change in height within a gravitational field the work done against gravity in the upward expansion is exactly matched by the expansion with gravity in the downward expansion for zero net work overall hence no change in temperature.
Also, for expansion with no change in height there will be no movement of kinetic energy in or out of the parcel by way of work done on surrounding molecules because all the molecules involved both inside and outside the parcel average out to the same temperature and pressure.
So I think Kristian has it wrong about the established science rather than me.
Stephen Wilde, July 26, 2015 at 7:24 pm:
“So I think Kristian has it wrong about the established science rather than me.”
Sorry, Stephen. This is not a matter of opinion. The adiabatic process works by the air expanding against a reduced external air pressure, thus doing work on the air surrounding it, thus losing internal energy, thus cooling; conversely it works by the air contracting against an increased external air pressure, thus having work done on it by the air surrounding it, thus gaining internal energy, thus warming.
Q = 0, so ΔU = -W. 1st Law for the adiabatic process. Look it up.
When you release carbon dioxide from a fire extinguisher, it quickly expands, cools and condenses as a result. It does so whether you shoot it downwards or upwards or just straight ahead. Meaning, gravity doesn’t matter here. Only the swift expansion against a lowered external pressure does. Same with a cylinder piston. The air warms as the piston quickly compresses it and cools as it falls back, letting it expand again. This happens to the same extent whether the piston is working in an upward or in a downward or in a horizontal direction. Gravity takes no part. This is the adiabatic process, and it works by the exact same physical principles in the atmosphere as it does in these two examples, only there the air volume in question will have to move vertically for the external pressure to change.
This is just how it is. It doesn’t matter what you “think”, Stephen. This is how the adiabatic process works. Period. Gravity takes no part in it. That’s just your delusion.
I’m not happy with paras 3 4 and 5 above so please ignore. Para 1 is OK.
You can’t have expansion with no change in height within a gravitational field because the added thermal energy that needs to be supplied diabatically in order to cause the expansion creates a density change that inevitably leads to adiabatic uplift.
“Stephen. This is how the adiabatic process works. Period. Gravity takes no part in it”
Obviously wrong:
http://www.britannica.com/science/lapse-rate
“The dry adiabatic lapse rate for air depends only on the specific heat capacity of air at constant pressure and the acceleration due to gravity”
That’s the lapse rate, Stephen. Not the adiabatic process.
Sigh
The adiabatic lapse rate is a product of the adiabatic process.
Work done against gravity is integral to it and NOT work done against surrounding molecules. The latter is a diabatic process because heat moves in or out which is not permitted for an adiabatic process.
The former does not move heat in or out. The heat energy is transformed to or from PE instead.
Stephen, you say: “Work done against gravity is integral to it and NOT work done against surrounding molecules. The latter is a diabatic process because heat moves in or out which is not permitted for an adiabatic process.”
You don’t know ANYTHING about these things, do you? You haven’t read ANYTHING about even basic thermodynamics. And still you comment on this issue as if you words alone were enough to verify your nonsensical claims about reality. Unfathomable.
First you need to familiarise yourself with the 1st Law of Thermodynamics, what it is and what it says.
Then you need to know how ‘heat’ [Q], ‘work’ [W] and ‘internal energy’ [U] is defined in thermodynamics. They are both terms in the mathematically expressed version of the 1st Law.
Further, you will have to read about the basic definition of an “adiabatic process”. How is it expressed mathematically? And how does it connect with the 1st Law?
During this learning process you will encounter the term “PV work”, pressure volume work. PV work is the kind of thermodynamic work that operates in an adiabatic process. You can read about it here:
https://en.wikipedia.org/wiki/Work_(thermodynamics)#Pressure-volume_work
The work done by the system in an adiabatic process is PV work, thus it involves the internal and external pressures of the system, where the system expands against the external one (the surrounding pressure), thus doing (PV) work ON the surroundings. It’s there in black and white, Stephen. Once again. Like I said, this is not a matter of opinion. This is not about what you think. It’s about what the physics says.
There is much more to learn even after this, but start with this. It should occupy you for a while.
Kristian,
When expansion occurs during uplift the movement is towards an area of lower pressure.
No work needs to be done against surrounding molecules in that situation.
The rising parcel simply expands into the space made available by the less dense, lower pressure, medium,.
The only work that is necessary is work against the downward force of gravity and the equations work perfectly well in that scenario.
Convective overturning is not like a rising parcel pushing static gases above it out of the way and thus doing work against them in order to ‘win’ additional space for expansion.
Once the first convective overturning cycle completes, the entire cycle is in constant motion upwards in one column and downwards in the adjacent column.
Thus as fast as a rising parcel expands into the lower pressure space above it the molecules in that higher space are themselves moving out of the way by rising even further up and reducing their own density. No work is needed between rising molecules and the molecules above them.
Let’s try and get to the nub of the disagreement about the adiabatic process between me on the one hand and Kristian on the other.
As I recall, Kristian accepts that, for a process to be adiabatic, heat cannot transfer in or out AS HEAT.
I agree with that.
Kristian then said that heat can be transferred in or out AS WORK without the process ceasing to be adiabatic. Thus, rising molecules can do work on surrounding molecules so that heat transfers, from the rising parcel which cools, to the surrounding molecules which warm.
I disagree with that.
Is that a fair summary of the point in dispute ?
If so, then I will proceed to explain why I disagree with the second part but there is no point in doing so unless I have correctly identified the issue.
Stephen 5:08am – I will try to help, again, since you can’t read math. Lapse means a decline of something over a distance.
Neither of you are being mathematically precise. For the derivation of the dry adiabatic lapse rate in the 1890s, -g/Cp ~ 9.8K/km for earth, for the math to be simplified & proceed, which you can’t just imagine, Poisson assumed the expansion process (by reading thru his derivation not wiki, not a link on the net, but his original work) takes place:
1. at the same temperature as the surroundings T=Ts, and
2. at same pressure as the hydrostatic surroundings P=Ps. These two allowed him simpler integration over the z height.
And 3. no condensation, not moist, so dry.
Condition 2. means no work was assumed to be done on or by the air in the expansion process to derive the DALR. The cooling T comes from only gas expansion with z increasing due to surrounding pressure, density decreasing:
P(z)=density(z)*R*T(z).
So if P down, density down, then T down in the expansion process.
Poisson then went on to relax the condition on T equal to surroundings (keeping 2. and 3.) and found a more precise ideal troposphere lapse derived with integration that was more time consuming effort, you can see all this in his math if you could read it:
T(p) = To * (P(z)/Po)^R/Cp
None of this really happens in the troposphere as this work is ideal, that is why the ELR is the natural lapse existing in nature, needing RTM analysis or thermometer on a rocket/balloon to know at a given location with increasing z. The Stnd. Atm. curve fit existing midlatitude soundings and drew a straight line through them at exactly 6.5K/km guided by idealism. Closer to hub?
In the standard committee voted 6.5K/km, T is not equal Ts, P not equal Ps, and there are sometimes on avg. clouds, i.e moist not dry. Interestingly, this can be solved rigorously mathematically too but too advanced for your limited math skills to even attempt to discuss.
NB: I did not use “adiabatic” term in discussion except in DALR, did not use “heat” term, these are imprecise. Cause confusion.
Trick,
You have completely missed the point at issue.
Actually, Trick, this bit is useful:
“Condition 2. means no work was assumed to be done on or by the air in the expansion process to derive the DALR. The cooling T comes from only gas expansion with z increasing due to surrounding pressure, density decreasing:”
Kristian’s proposal seems to be in breach of that condition 2. Since gravity creates the decline in surrounding pressure and density one could argue that work is being done against gravity, just not against surrounding air molecules.
Stephen – A swing and miss then a hit for assumption 2. in 1st sentence at 8:54am. Pressure P=Ps does mean Poisson assumed no work done.
“..one could argue that work is being done against gravity..”
What did I just write? No, Poisson’s math moved forward with no work at all being done in the process of the gas expansion, P=Ps. g entered into the mix from the hydrostatic equilibrium of the atm. in that surroundings pressure gradient = -density of surroundings * g. Then P=Ps was key assumption.
It is ok to think of the air rising and doing work against gravity separately Stephen but you continuously miss the pv term in that discussion so it goes nowhere & sets Kristian off as at 9:34am. The specific enthalpy of a parcel decreases as it rises Stephen, not just the molecule KE, as I’ve repeatedly & futilely noted for you. For that you DO need the pv term to account for the work done by the parcel on/from its surroundings as in Kristian’s 9:34am.
I have noted you have recently written of the forces between molecules which is progress, THAT is where the important pv term arises in test and it is part of the conserved quantity “dry static energy” in the process of adiabatic ascent or descent but you have resisted this notion, focusing incorrectly on just PE+KE.
It may be useful to note that Poisson did not even need to consider the parcel in motion, he just used the mathematical process it would undergo from T=Ts and P=Ps & dry. He simply differentiated over z height one of his relations from the ideal gas law connecting p,V,T and made the assumptions I noted along the way. I would lay the calculations out but it would be futile.
Trick,
You are raising straw men from what I say.
I have it right as confirmed here:
http://virakkraft.com/Experimenting%20on%20a%20Small%20Planet.pdf
Kristian is wrong.
Work is done against or with gravity when the volume changes and not against surrounding molecules.
Stephen – No strawmen. That short paragraph article doesn’t have much if any foundation. You can do a lot better. “Cools by expansion” is sort of mixed with rising and descending work. Two different math concepts are simply mixed up.
Kristian is right about the pv term for ascending and descending work being done by surroundings, intermolecular forces and from gravity in ELR; Poisson is right about the “cooled by expansion” when no work is done DALR. Again, cooled by expansion is DALR no work, but when work is done you have the ELR. That paragraph confuses & mixes the two. You could easily see this if you could read the math involved, but alas you cannot. It is futile to convince you otherwise as I noted. Keep searching for a link that gets it not so confused, you know like a good text book, make it not futile.
It is the gravity field which comprises the relevant ‘suroundings’ against which work is done when a gas volume changes due to uplift and descent and not the surrounding molecules.
Kristian is wrong but neither he nor you will ever admit it.
Stephen – Again, the gravity field g only enters the DALR derivation as I wrote through hydrostatic equilibrium of the atm. in that surroundings pressure gradient = -density of surroundings * g. Then assuming Ps=P of the subject air. There is no motion against g.
For the DALR derivation is from simply taking the derivative dT/dz of the 1823 Poisson relation drawn from IGL, hence there is no motion against gravity at all in the DALR as work=0. The gas cooling is 100% from its expansion. In 1888, Helmholtz extended the work (with tougher integration of differential T not constant due advancement in calculus) to the formula I gave earlier and it became commonly known in meteorology as potential temperature in the 1890s.
Motion against gravity comes in the reduced ELR, work not equal 0, upon parcel ascent and descent against/for gravity which also brings in the pv term that Kristian discusses and you have never accepted, unfortunately, p*v energy is hard to imagine but you are getting there discussing intermolecular forces acting over a distance. Feynman: molecules close in repel, when they get far away molecules attract.
The motion against g occurred when the gases first rose off the surface. That was when the DALR was first put in place.
This is what is wrong with Kristian’s account:
Let’s look at Kristian’s use of equations.
He uses W (work), Q (heat) and U (internal energy).
For the starting point we can set all three at 0 because we are interested only in changes and not absolute values.
Kristian says that work can take place against surrounding molecules (say 1 unit of work) which reduces internal energy (by say 1 unit) but that Q can nonetheless remain at 0.
That contradicts his assertion that a reduction in internal energy results in cooling. In fact, reducing U by 1 unit must also reduce Q by 1 unit if the units of internal energy are kinetic energy rather than potential energy.
So how has he become so confused?
Kristian said:
“if there is cooling of the system, meaning, a reduction in system U, it can only be caused by a transfer of energy out of the system in the form of ‘work’ [W].”
However, work is NOT a ‘form’ of energy. Work is a process whereby energy can either be transformed (say KE to PE or back again) or moved (inside or outside of the initial volume).
Since he is wrongly asserting that work is a form of energy he thinks that 1 unit of work (+1) can offset a reduction of internal energy (-1) to leave Q on the other side of the equation at 0. He thinks that the unit of W is a form of energy that can be added back to the reduced internal energy to leave Q unchanged.
In fact what happens is that 1 unit of W will either transform 1 unit of U from KE to PE which reduces both U (if internal energy is defined as kinetic energy) and Q by 1 unit
OR
1 unit of work will move 1 unit of U out of the parcel which also reduces the Q of the parcel by 1 and in order to conserve energy the air outside of the parcel must gain 1 unit of internal energy and 1 unit of Q. Just as before, the initial parcel shows a reduction of 1 unit in both U and Q.
The former involves work against gravity (adiabatic since no internal energy is lost or gained by the parcel, simply a transformation from KE to PE) and the latter involves work against surrounding molecules (diabatic because some of the internal energy has moved out to the surroundings).
The temperature change in the real world is overwhelmingly the result of the adiabatic process arising from work done against gravity.
Stephen – “The temperature change in the real world is overwhelmingly the result of the adiabatic process arising from work done against gravity.”
No sir, the DALR is ideal not the real world Stephen, its cooling results 100% from expansion, not from work done against gravity, you can imagine for each molecule rising, one falls in the expansion process undergone by the gas of interest. The ELR is real world where the rising and descending parcels conserve the “dry static energy” not just KE+PE since there are forces between the molecules compressing & expanding which is also conserved (can’t destroy or create that existing energy either).
“..work is NOT a ‘form’ of energy..”
Has no meaning I can see, work is energy, a force over a distance of which there is none (W=0.0) in the derivation of the DALR arrived at in the 1800s, work was set = 0.0 in that original derivation taking dT/dz of an ideal gas under hydrostatic conditions & the 3 conditions I noted.
Recommend reading David Deutsch on chemical scum living on a typical rock in a typical etc etc
Stephen Wilde, July 28, 2015 at 6:39 pm:
“Kristian is wrong.”
*Sigh* Yeah, I thought you might like that source. I’ve discussed lgl’s peculiar “finding” with him at the site where he first brought it to our attention. It’s wrong. In fact, it’s stupidly so.
This Hay-fellow (as esteemed as he might be) does two fundamental (and quite amateurish) mistakes:
1) Like you, he cannot separate between ‘heat’ [Q] and ‘internal energy’ [U], and therefore cannot understand that energy is in fact lost and gained by the system during the adiabatic cycle, through ‘work’ [W] performed on and by the system, by and on its immediate surroundings.
2) Like you, he thinks by doing thermodynamic ‘work’, KE is somehow simply transformed to PE inside the system performing the work, instead of that system actually spending the energy while performing the work. In thermodynamics, when you do ‘work’, you use energy and you transfer it to the system that you do the work on. You do not just tranform some of your own internal energy from KE to PE. That’s not just ridiculous. It’s simply un-physical. Contrary even to Newton! If you do work and don’t transfer energy to the thing your doing work on, then you are not doing work, because you cannot accomplish any change.
Both of these points are elementary in thermodynamics (the second one even in Newtonian mechanics). Especially the second one is an egregious mistake to make. Simply because it’s so obvious.
BTW, Stephen, me and several others have provided you with an avalanche of sources over the years who say exactly the opposite to this one guy. You have never acknowledged even a single one of them.
I have seen a couple of other sources displaying the same kind of fundamental miscomprehension of this issue as this one does. They do exist, for sure. But they are (luckily) rare. All educational texts on the subject (i.e. the things actually taught at universities all around the planet) say the same thing, very consistently. I’ve shown you tens upon tens of examples of what they say before, and I know it’s still no use, because you just go lalalalalala anyway, but here are two more (randomly picked):
http://www.geog.ucsb.edu/~joel/g110_w08/lecture_notes/cooling_processes/cooling_processes.html
http://snowball.millersville.edu/~adecaria/ESCI107/esci107_lesson05_stability.pdf
From the first source:
From the second source:
I can keep going …
Read my post at 10.52 pm
Why? You clearly didn’t read my post. Once again it’s right there in front of you. In black and white. And you just ignore it. And move on with you own personal takes on science, physics and reality. It’s hopeless.
Here’s another source to enlighten you (one you should really read through thoroughly):
http://farside.ph.utexas.edu/teaching/sm1/lectures/node56.html
I will remind you once again, that ‘work’ in thermodynamics is defined like this:
https://en.wikipedia.org/wiki/Work_(thermodynamics)
Worth noting from the same source (for you in particular, Stephen, who seems to have a complete blind spot when it comes to differentiating between the transfer of energy as ‘heat’ [Q] to/from the system, the transfer of energy as ‘work’ [W] to/from the system, and the energy held inside the system, the ‘internal energy’ [U]):
http://www.geog.ucsb.edu/~joel/g110_w08/lecture_notes/cooling_processes/first_law.gif
See, Stephen? Two different types of energy transfer. In an adiabatic process, only the arrows to the left, the ‘heating’ [Q], is defined as zero, not the arrows to the right, the ‘working’ [W]. Because the ‘working’ arrows involve the expansion and the contraction of the air parcel, against a reduced and an increased outside air pressure respectively.
The energy inside the parcel is NOT what’s called ‘heat’. That’s ‘internal energy’, the U.
Any source which refers to work in an adiabatic process being done on the surrounding air is wrong.
The usual terminology is ‘surroundings’ or ‘environment’, both of which which accommodate
the gravity field.
You might try this:
http://hockeyschtick.blogspot.ca/
Given a choice between you and Feynman the decision is obvious 🙂
Stephen Wilde, July 29, 2015 at 3:35 am:
“Any source which refers to work in an adiabatic process being done on the surrounding air is wrong.
The usual terminology is ‘surroundings’ or ‘environment’, both of which which accommodate
the gravity field.”
Of course, if Professor Stephen Wilde says so, we have accomplished instant Truth. It just has to be so. His words alone do magic. They turn things into facts by simply being stated.
So the cooling of the air inside a cylinder as the piston relaxes and falls back is not adiabatic. The cooling of the air coming out of a punctured tire is not adiabatic. The cooling and resulting condensation of CO2 as it comes out of a fire extinguisher is not adiabatic. Because the expansional work done by the gases in all these examples are performed on the surrounding air and not on the gravity field. And so they are not adiabatic. According to Professor Stephen Wilde. If gravity doesn’t cool the gas, then it’s not adiabatic cooling. It’s … something else.
Yup. Welcome to the cuckoo’s nest!
Strange, then, how NONE of the educational texts and lectures on the adiabatic process in the atmosphere EVER mentions the ‘gravity field’ as a player, don’t you think? How the ‘surroundings’ or the ‘environment’ is NEVER specifically stated to include the gravity field.
Or, I guess you just have to know that, don’t you, Professor Stephen? It will never be stated. It’s just a hidden fact that only a few are allowed to utter. Right?
The expansion of the air parcel is done against the surrounding pressure, Stephen. The outside pressure of the air immediately surrounding the air parcel. That is what is stated. Again and again and again. Gravity is never mentioned.
Looks like my reply to Kristian tripped the moderation filter so I hope the mods approve it shortly.
While I wait for my full reply to be released I’ll just mention this :
Kristian said:
“The expansion of the air parcel is done against the surrounding pressure, Stephen. The outside pressure of the air immediately surrounding the air parcel. That is what is stated. Again and again and again. Gravity is never mentioned.”
If the ambient pressure were the same as or higher than the pressutre in the ascending parcel then you would be right.
However, gravity sets up declining pressure with height so the ascending parcel is expanding into a region of lower pressure.
Thus the surrounding molecules present no resistance and no work is done against them by the rising parcel which simply expands into the space made available by the lower pressure.
The only work that needs to be done is against gravity as the molecules move apart to fill the space made nrewly available during the ascent.
Try resubmitting that with a URL shortener and less caustic language
I’m just looking at this from the perspective of a layman quant with expertise elsewhere but for whom only quantitative relationships count .
Even the importance of the total energy impinging on an orbit has been so suppressed in this field that I’m not sure whether Kristian will agree that at the top of an atmosphere the temperature must converge on the temperature corresponding to that total — in the case of Venus , about 328K , Earth , 279K .
The next parameter to be considered is the planet’s spectrum as seen from the outside and its correlation w that of the Sun .
After that , and in many ways the big mystery is how heat can actually be “trapped” . How can the interior of a ball remain perpetually hotter than the temperature calculated for its surface ?
This discussion , and Hockey’s calculations and observational confirmation ( and Kristian’s graphs ) — which I have yet to work thru and implement myself , and probably won’t for at least a month , has made it clear that gravity is the force which cannot be ignored .
It is the next non-optional parameter .
It doesn’t matter the details , it is the sum of gravitational ( considered a negative ) and thermal energy which must be in balance with impinging radiation . Working out the equations should be , and apparently are , fairly simple from there .
But this is a basic change in world view . It extends to the very center of a ball . It means that even without radioactivity , the core of the earth will always be far hotter , by an easily calculable amount , than the surface as long as the Sun shines .
I wonder if Chandrasekhar covers this . I think he must .
Bob,
The interiors of large enough solid objects do indeed heat up as a consequence of gravity compressing the matter of which they are composed to a density higher than the molecular bonds would otherwise determine.
It is the struggle between the force of gravity and the molecular bonds that generates the kinetic energy.
That is part of the general physical characteristics of matter throughout the universe and if the aggregations of matter are large enough one gets the creation of suns when the force of gravity generates enough interior heat through the compression of matter to let fusion commence. Ultimately one can achieve creation of black holes (if they do actually occur).
The thing is, though, that it takes a lot more mass and much stronger gravity to create heat within solids and liquids than in gases simply because gases are magnitudes more compressible and so generate kinetic energy within a gravitational field much more readily than do liquids and solids.
I don’t think any of this is new since I learned it decades ago.
What seems to have happened is that the link between such astronomical processes involving planets and suns and the similar but magnified effect within gases has not been noticed by those climatologists who try to explain everything in terms of radiative balances.
That link was known decades ago because I was always taught that the high surface temperature of Venus was due to the compression of dense gases by gravity, long before anyone tried to explain it with radiative theory.
Stephen/Bob – As the planet compressed there was f*d energy increase; infalling matter brought KE with it. After this process completed there is f of gravity but no f*d (i.e. f*0) so no energy increase any longer except by radioactive decay which has f*d in itself.
Bob’s global surface Tmedian 279K comes from incorrectly considering the global atmosphere emissivity 0.6 when it has been actually measured ~0.7 looking up in coldest, dry polar regions and .95 in humid tropics. Confirmed by lowest DW IR recorded in polar regions around 130W/m^2 , where 0.6 would result in DW IR substantially lower around 102 W/m^2 which has never been observed naturally anywhere.
Tridk : “Bob’s global surface Tmedian 279K comes from incorrectly considering the global atmosphere emissivity 0.6 ”
NO ! . Absolutely totally WRONG .
It simply comes from adding up ( integrating ) all the radiant energy impinging on a point in our orbit .
Watch my Heartland presentation on How to Calculate the Temperature of a Radiantly Heated Colored Ball ,
http://climateconferences.heartland.org/robert-armstrong-iccc9-panel-18/ if you don’t understand why that is the only computationally relevant value .
The next parameter after that to be added to the computation is the full spectrum of the planet as seen from space . It is retarded , as I have pointed out above and elsewhere to keep perseverating on crude step function hypothetical spectra when actual measured spectra are available .
“As the planet compressed there was f*d energy increase; infalling matter brought KE with it. After this process completed there is f of gravity but no f*d (i.e. f*0) so no energy increase any longer except by radioactive decay which has f*d in itself.”
Depends on the size of the aggregation of mass of the planet. I didn’t commit myself as regards Earth because I don’t know the answer.
I’m going to cc Alan Guth on this .
I got to get ready for my closest Saturday to MidSummer 3 days hence .
Stephen , The thing is , I always thought of the gravitation heating as being a dynamic heating of accretion . But , given an external radiant source , the interior has to be hotter by the calculated gravitational energy than that calculated for its surface to be in radiative balance with that source .
Thus Kelvin needed not have worried that the Earth’s core would ever cool to its surface temperature .
I really look forward to having time to explore the computations , but for right now my priorities are more about testing that the function I made yesterday in my open and free 4th.CoSy to count the portion of Nobel laureates willing to sign onto CAGW :
: PoT 1p R@ur momisugly R@ur momisugly +/ %f 1P> ; | Proportions of Totalf( 30 35 )f PoT |>| 0.46153 0.53846
works perceptually instantaneously on a string of a million numbers and doesn’t bomb using my new stack frame definitions of those parameter push and Pop fns .
Bob 12:25pm – I have listened to your lecture and looked through your .ppt with obtuse nomenclature.
I will stand by what I wrote.
For instance, you multiply temperature on slide 24. This would imply 2 cups of room temperature water combined can multiply 2 * 72 = 144F. Not true. So 0.98*279K is not 273.4K.
Your chart on slide 11 gives no source, T does not appear to be correct from the usual sources.
You simply announce the 279K which is equiv. to global near surface Tmedian calculated from atm. at 0.6 emissivity looking up from surface on a simple balance (see e.g. Bohren 2006 text p. 33), no calculation given, no source. In fact I see no source given for any of the data.
I’m sorry you do not follow the computation of the temperature of a gray , flat spectrum object in our orbit simply from the temperature and radius of the Sun and our distance from it .
I spend a couple of slides on why the notation . In such APLs a functioning model of planetary physics can be written as succinctly as it can be expressed in any physics text . My friend Morten Kromberg recently gave a Google Tech Talk on his company’s APL which may help understand why these notations are worth learning : https://www.youtube.com/watch?v=PlM9BXfu7UY . I understand that Roy Spencer’s new system , still in FORTRAN , is under 10,000 lines . I consider that a remarkable achievement and clearly has to deal with a score of factors . In well written APL , I cannot imagine it taking much more than a hundred lines — mostly brief definitions . All of the code for the computation of equilibrium temperature of a ball with an arbitrary absorption=emission spectrum and arbitrary source spectrum are contained on the my slides .
You think I really need references for this slide :
http://cosy.com/Science/CO2vTkelvin.jpg
I believe it is universally accepted that our temperature has change from about 288K to 289K while CO2 has gone from about 290ppm to 390ppm . What’s to reference ?
Your comment on this slide
http://cosy.com/Science/WaterEquilibriumTemp.jpg
makes me wonder if you understand slide 10 which explains what I consider a grade school fact that only the 0 based Kelvin scale is useful in multiplicative computations .
Frankly , you come across to me as symptomatic of the utter retardation of the understanding of essential undergraduate math endemic in this field , prerequisite in any any other branch of applied physics , eg , semiconductors .
“You think I really need references for this slide :”
Yes. With citation.
“What’s to reference ?
The source of the data.
“..a grade school fact that only the 0 based Kelvin scale is useful in multiplicative computations .”
You can talk about delta temperature in grade school, 289K being 1K higher than 288K. Cannot multiply, cannot add 72F to 72F to get 144F, or zero based 288K + 288K = 576K.
https://en.wikipedia.org/wiki/Intensive_and_extensive_properties
“…makes me wonder if you understand slide 10…”
Let me remove all wonder, I do not understand slide 10. Fill me in. Start with what altitude is the 279K you discuss, is it global, annual spatial & temporal avg.? What? And what is a flat spectrum in the context of climate?
To claim that it is “accepted that our temperature has change from about 288K to 289K while CO2 has gone from about 290ppm to 390ppm .” needs some specific reference is just silly among this audience . I use the word “about” twice because the point is simply that dT%dCO2 at these concentrations is at most on the order of 0.01 .
I am NOT multiplying or adding 2 temperatures . I am multiplying the gray body temperature by the 4th root of a ratio of dot products . Perhaps my best phrasing so far in at http://cosy.com/Science/RadiativeBalanceGraphSummary.html :
The conversion of that statement of balance to the product of the gray body temperature times the 4th root of the ratio of absorption to emission is the subject of slide 23 , http://cosy.com/Science/AGWppt_AEratioCalc.jpg . Martin Hertzberg derives the same formula in a less general way .
I’m curious if you know what a dot product is . It is arguably the most fundamental computation of existence .
It appears to me that you have learned to parrot the 33K meme while never learning how to calculate the value for any arbitrary spectra . This should be absolutely core curriculum for anybody claiming even college level expertise in the field . The ubiquitous ignorance of even these most basic non-optional computations is what drove me to divert a painfully costly amount of time and energy into this battle against tyrannical nonscience .
Trick ,
I see you are right that my description of the necessity of 0 based scales is insufficient . Of course it is computations in energy , ie ,
T ^ 4which are linear . That’s why its the 4th root of the absorption%emission ratio which is used in the computation in terms of temperature .I’m surprised the phrase I commonly use “gray body in our orbit” is ambiguous . And I explicitly state it is calculated simply by summing the total energy impinging on a point in our orbit . It has nothing to do with atmosphere or observed Earth temperatures at some altitude or whatever . It is simply the StefanBoltzmann temperature calculated from the observed temperature of the Sun and the portion of the celestial sphere it subtends viewed from our orbit . It is the same for any shade gray from black
ae = 1to almost white ( there is a singularity , of course atae = 0) .Trick ,
I thought of another way to relate the 279K value to something you know . ( but also which I hoped my graph at July 22, 2015 at 6:24 pm tried to make clear . It’s the temperature corresponding to total top of atmosphere insolation . In 4th.CoSy current reverse Polish given the Stefan Boltzmann constant , 5.670373e-8 :
279. 4. ^ 5.670373e-8 * |>| 343.58 | 279K correspond to ~ 343.58 w%m^2 over the sphere .
343.58 4. * |>| 1374.32 | multiplying by ratio of surface of sphere to that of disk .
Does that make it clear ?. It’s the temperature of a sphere in our orbit before any spectral parameter is considered . It is what Wikipedia and NASA should label the black body
==gray body temperature .“I am NOT multiplying or adding 2 temperatures .”
This sure appears to be your doing so on the slide: 0.98 * 279 for 273.4. You are multiplying a number & temperature, which has no meaning as in 2 * 288K = 586K is not correct.
You are right that you cannot add temperatures without taking their 4th power to convert to energy in which computations are linear and then taking the 4th root .
However in Kelvin it does make sense to multiply and divide . It makes perfect sense to say that 200K is 2 times 100K . Note the multiplier 2 is dimensionless . It makes perfect sense because
200 ^ 4is2 ^ 4times100 ^ 4.“It makes perfect sense to say that 200K is 2 times 100K .”
You can do the calculation Bob, but no physical sense is made, unless you can demonstrate 200K water ice added to 200K water ice creates a a mix of liquid water boiling away at 400K.
What level are you at in school ? I hope it is not beyond high school .
There are some very basic issues you fail to understand .
Saying one temperature is twice another is NOT the same thing that if you add one mole of water to another mole of water at the same temperature the 2 moles of water will be 2 times the temperature .
You demonstrate that you DO NOT understand the necessity and import of the Kelvin scale .
Bob – It is you on your slide saying that not me! with your multiplying a temperature in K by a factor, you need to correct that slide. Then I’ll have a look at the rest.
I conclude that you have never had a college level or even good highschool level physics class .
By your (ill)logic even a thermometer would be impossible . Think about it . There is only an affine transformation between temperature scales .
You are coming close to revealing yourself to be a willfully dishonest troll .
Bob – Nothing to do with a thermometer. You multiplied a number by a temperature on your slide, I explained this is nonphysical, intensive properties include temperature. Pretty simple: your slide showing 0.98 * 279 for 273.4 needs to address this issue.
You are a willful troll who fails even high school math .
F
I’ll simplify and shorten the whole thing and repost shortly.
Kristian said:
“Strange, then, how NONE of the educational texts and lectures on the adiabatic process in the atmosphere EVER mentions the ‘gravity field’ as a player, don’t you think? How the ‘surroundings’ or the ‘environment’ is NEVER specifically stated to include the gravity field.”
One of your own links over at Tallbloke’s said this:
“there are two separate kinds of work being done here. Simply because we’re operating in a gravity field”
In relation to which I commented to you:
“The first kind of work is the raising vertically.
The second kind of work is the moving apart of molecules into lower pressure.
Both involve work against gravity and NOT against surrounding molecules. The link says as much since both types of work are explicitly mentioned as a consequence of ‘operating in a gravity field’.”
And there is this item:
http://hockeyschtick.blogspot.co.uk/
which discusses work against gravity in some detail.
All the authoritative sources emphasise the importance of gravitational acceleration in connection with adiabatic uplift and descent but I accept that some sources, misleadingly, do refer to work being done against surrounding molecules and that has caused your understanding to be faulty.
The examples you give are not applicable since they do not involve changing height within the gravitational field.
Stephen 9:58am: “The first kind of work is the raising vertically. The second kind of work is the moving apart of molecules into lower pressure. Both involve work against gravity and NOT against surrounding molecules.”
Both are in the math of the ELR, neither in DALR math.
Yes, the “first kind” is for ELR parcels considered ascending and descending in a gravity field.
The “second kind” though is independent against the force between molecules (not against gravity force) resulting in the p*v term, which you don’t acknowledge, from Maxwell’s reasoning and test around 1870. Here P of the air inside Kristian’s diagram may not equal Ps so there is a force over a distance called working in Kristian’s diagram when that is the case in the ELR, since v also changes the energy exchanged in the “working” arrows is p*v. This is not allowed in DALR since its math holds P=Ps so no force exists over the distance (which does exist).
Also there is thermal energy crossing the border as in Kristian’s diagram called “heating” both ways if T not equal Ts.
All of the energy crossing the border can be accounted for as conserved with z height changing & along with the existing internal energy (KE+PE), the sum of which with p*v term is called the “dry static energy” the proper conserved quantity – not just KE+PE being conserved as in your improper imagination that doesn’t line up with test.
You can find all this in a good text, in math and prose, internet links are subject to increased error propagation. Texts suffer that disease too, one appreciates the texts quoting the original work an increase of “goodness”. As I mentioned to you long ago.
Trick said:
“The “second kind” though is independent against the force between molecules (not against gravity force) resulting in the p*v term, which you don’t acknowledge”
Not correct.
The force between molecules has already been adjusted by the gravity field creating a declining pressure gradient with height. Gravity has previously done the necessary work on the molecules along the lapse rate slope so as to account for the p*v term even before uplift commences.
Thus there is no residual force between molecules opposing the expansion of a rising parcel when the expansion is into a region of lower density. The rising parcel simply expands to match the new ambient pressure and density.
That leaves the only force opposing expansion during uplift as the downward pull of gravity.
The necessary work of expansion is therefore done against that downward force.
As regards the rest of your post it is not relevant here. It is not disputed that there is some thermal leakage in and out of ascending parcels but that is a diabatic not an adiabatic process.
So Stephen – Do you have a proper test to go with your assertion(s)?
The ELR is always diabatic, the DALR always T=Ts and P=Ps so both Kristian’s arrows are 0.
The ELR is not all diabatic but it always has a diabatic component.
It is only diabatic to the extent that it diverges from the pure ALR determined by mass and gravity.
Even the DALR is partly diabatic because all matter has some radiative capability which allows leakage out from the adiabatic process.
Convection then adjusts to negate the diabatic components so that on average over time the ALR is achieved and the atmosphere retained.
The method of convective adjiustment is described here:
http://hockeyschtick.blogspot.co.uk/2015/07/erasing-agw-how-convection-responds-to.html
Stephen – nothing in nature is adiabatic, so it appears you have no tests backing your assertions, that site didn’t have any, your assertions remain speculative at best unsupported.
Nothing is purely adiabatic but there is adiabatic uplift and descent in so far as the work done is done against gravity.
Not even adiabatic uplift, ruled out by second law.
Don’t be silly.
http://eesc.columbia.edu/courses/ees/climate/lectures/atm_phys.html
With regard to the link I just gave you this is interesting since it may go some way to explaining Kristian’s confusion:
“As our air parcel expands in response to the lowering of the outside pressure, the force of its internal pressure is moving the walls of the container outwards. When a force is moving an object over a given distance it does work. Thus the expanding air parcel does work on its surroundings. This work must come at the expense of internal energy (remember, heat is neither added nor taken away from the parcel in this experiment). Thus the molecular motion within the parcel will slow down, and the parcel’s temperature will drop. ”
Note firstly that they previously referred to internal energy as kinetic energy only whereas potential energy should really be included. No doubt that was done for simplicity.
Note secondly that they refer to the walls of a flexible container and it is the walls of the container that are pushed out and NOT outside molecules being pushed away. There is no need to push outside molecules away because the lowered pressure outside the parcel has removed all resistance to expansion.
If there is no flexible container then the walls are effectively the outermost layer of molecules of the parcel and they cross a distance in response to the higher internal pressure of the parcel, not meeting any resistance along the way.
Work is done moving the molecules across the distance so it is that distance, that additional volume , which is the surroundings and NOT molecules outside the parcel.
In the process of crossing that distance work has to be done against the gravitational field which is constantly seeking to pull the parcel back down and compress it once more.
It really is obvious that the relevant work is being done against gravity but people such as Kristian and even providers of some source materials have misunderstood the position and simply assumed, incorrectly, that work against external molecules was required.
Stephen – My stuff agrees with that link, so nothing silly. In that link you don’t discuss the “outs” afforded by the discussion:
“the expanding air parcel does work”
Here they are discussing the ELR as Kristian’s arrows for working are stated non-zero, in contrast the DALR derivation the working arrows are 0 since P=Ps. This is a clue you miss all the time it seems.
“It really is obvious that the relevant work is being done against gravity”
Yes, for the ELR.
“the ideal gas law (ideal because it is not exact..”
IGL is ideal, not exactly reality. The adiabatic lapse rate DALR is NOT measured, the ELR is:
“The measured local vertical profile of temperature in the air is called the environmental lapse rate.”
Measured is real world.
“..rising air cools adiabatically…”
Here in context they are discussing the DALR with T=Ts and P=Ps.
“Water vapor is an absorber of infrared radiation..”
See? They even discuss mixing ratio – a term I have used. This link is ok but not “good” as it just announces things without telling us the original sources that relied on test for the “things” originally said, which is very unsatisfying.
Anthony Watts. It is the ROTATION that is the difference.
1) average temperature is irrelevant. We blow through it in a second twice per day. The Earth has a day temperature and a night temperature.
2) Compare the Moon and the Earth temperatures. The moon has much higher day temperatures and much colder night temperatures due to its lack of atmosphere and slow rotation.
3) Rotation. This is the key difference between the Earth and Venus. The Earth rotates in 24 hours. Venus, what I’d it 300 plus days?
4) Venus day/night cycle is extreme, like the moons, because of its long day/night cycle.
5) Venus would be much cooler if it rotated ever 24 hours.
The most profound effect of an atmosphere , and GHGs is to reduce diurnal variance . But I have never seen an analysis of this effect which vastly exceeds any effect on the mean .
My understanding is , and what made be believe Venus’s surface temperature must be due to internal heating , that it’s pre-dawn temperature is almost indistinguishable from it’s evening temperature ~ 114 days earlier .