Climate Discussion Group 2024, CDG2024
Discussion - Climate C6
October - November 2024
C6 Thermalization of inbound visible sunlight and de-Thermalization of heat energy back to IR radiated to space.
Nov. 28, 2024
Tom Shula USA
On The Dynamics Of Thermalization Of The Atmosphere
Below are a few excerpts. Read the entire article at the link above.
The exchange between David Burton and Will Happer in this thread is most interesting. This predates the works initiated by van Wijngaarden and Happer by 5 years, and Markus Ott and I have studied this process in detail. I strongly recommend the reader watch Markus Ott’s video:
Convection and Thermalization Kills the Greenhouse Effect and read our essay:
The "Missing Link" in the Greenhouse Effect , recently submitted for posting on this site.
One misconception I have noted in various discussions is the “thermalization of sunlight.” The sunlight is not thermalized, at least not directly. Thermalization generally refers to the redistribution of energy amongst an ensemble of particles such that they reach a distribution approaching thermodynamic equilibrium. In the case of our planet, sunlight heats the surface. The heat energy can be transferred from the surface to the atmosphere in two ways.
The first is via conduction when air molecules collide with the warmer earth surface and increase their energy via transfer of heat increasing their velocity. At STP, about 50 kg of molecules/sq-meter/sec collide with the surface. The energy transferred will be proportional to the difference in temperature.
The second mechanism for transfer of heat is via the thermal radiation from the surface which is absorbed by IR active molecules. This absorption is effectively complete within ~ 10 meters above the surface. The balance between these two processes will change with varying levels of solar insolation.
The troposphere is in a continuous state of attempting to reach equilibrium (but it never gets there.) The molecules at a given altitude will all have a distribution of kinetic energy following a MaxwellBoltzmann distribution according to the local temperature. The excitation and de-excitation
(thermalization) of the IR active molecules are driven not by absorption and emission, but by collisions with other molecules. It is replenished by, but independent of, the energy received from conduction and absorbed radiation at the surface.
Referring now to the Happer/Burton discussion, some correction of the numbers is needed. The collision rate of air molecules is about 7 billion collisions/second, so the mean time between collisions is around 150 picoseconds. The deexcitation/thermalization that Happer refers to does not occur for every collision. Non-radiative deactivation rates have been measured very precisely by Siddles, Wilson and Simpson( The vibrational deactivation of the (00o1) and (0110): Modes of CO2 measured down to 140 KScienceDirect ), and at STP the average deactivation time for the bending vibration of CO2 is about 10 microseconds. This is discussed in detail in both of our references linked at the beginning of this comment. This means each CO2 molecule will experience about 50,000 thermalizations/second. This is a difference of four orders of magnitude relative to what Happer alluded to in the discussion. These thermalizations of excited CO2 transfer heat to the non-IR active molecules and together with the heat from direct conduction this drives convection in the troposphere from the bottom up. ..
A similar process occurs for all IR active species. In the case of water vapor, it emits across almost the
November 30, 2024
entire IR band and so can be excited by a larger population of collision partners. I have not found a reference estimate for H2O but would expect it to be considerably larger than the 4.4% for CO2.
This random radiation field does not transport energy in any specific direction. The energy transport upwards in the atmosphere is the result of convection. The thermal (kinetic) energy is distributed amongst ALL molecules. In addition, there is the latent heat of water vapor. The transport of this energy is performed by the mass transport of convection, not by the propagation of a radiation field.
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ecause water vapor is a condensing gas, its concentration in the troposphere drops precipitously with altitude. It may surprise you that water vapor emits across almost the entire spectral range, even in the so-called atmospheric window. You can see this in Herman Harde’s paper from 2013 Radiation and Heat Transfer in the Atmosphere: A Comprehensive Approach on a Molecular Basis - Harde - 2013 - International Journal of Atmospheric Sciences - Wiley Online Library. His figures 17 and 18 are relevant here. The tiny peak at the center of the CO2 band is not present in his figure 18 because the spectrum is modeled at 12.5 km altitude, well below the emission altitude of 86 km for CO2. I find his treatment considerably more November 30, 2024
rigorous and transparent than van Wijngaarden and Happer, though it predates them by a few years.
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The less obvious conclusion one can draw from this is that IR absorbing gases are solely responsible for removing heat from the atmosphere, contrary to the so-called GHE. It is the emissive properties of IRactive gases that cool the earth, contrary to the “conventional wisdom” that the absorptive properties cause the earth to warm.
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I find contrast between the Harde work and that of van Wijngaarden and Happer (vWH) interesting. In Harde, he provides a much more complete picture including what is effectively a derivation of Einstein’s Quantum Theory of Radiation paper with recognition and a complete treatment of the role of collisional excitation and de-excitation as the driving process in the dense lower atmosphere. This is discussed in passing at best by vWH. Harde includes convection specifically in his model, though only the minimal 3 W/m^2 promoted by the IPCC at that time. vWH states in some papers that convective energy transport is dominant in the troposphere but provide no treatment of it and proceed with using the RTE alone to describe energy transport. The one comment in the Burton/Happer that surprised me and that I agree with is that the emissions from the atmosphere a function of the temperature and composition,
November 30, 2024
Oct. 13, 2024
Terigi CicconeIntroduction
William HapperComment
Dan Pangburn –Author Canada USA
independent of the heat source for the atmosphere.
In both cases the authors are driven by a radiationcentric perspective and a desire to reconcile the concept of the GHE which cannot exist. The calculations of the equations that they present are correct. It is perspective that limits the interpretation.
"Climate Change Drivers* Dan Pangburn, P.E.** May 20, 2019. Last revised on 10/7/24. See
https://www.researchgate.net/publication/316885439_Clima te_Change_Drivers
At the end, there was a note from a reader to Will Happer, and Will responded to it. Essentially Will Happer holds the same Thermalization position Gerald Ratzer and Terigi Ciccone have.
Below is the communication exchange as Will replied to David Burton 10 years ago.
Especially note the very last question-reply "[YES, PRECISELY. WE HAVE BEEN TALKING ABOUT WHAT CHANDRASEKHAR CALLS AN “ABSORBING ATMOSPHERE” AS OPPOSED TO A “SCATTERING ATMOSPHERE.” ASTROPHYSICISTS ARE OFTEN MORE INTERESTED IN SCATTERING ATMOSPHERES, LIKE THE INTERIOR OF THE SUN. THE BLUE SKY DURING A CLEAR DAY IS AN EXAMPLE OF SCATTERING ATMOSPHERE. VERY LITTLE HEATING OR COOLING OF THE AIR OCCURS WITH THIS “RAYLEIGH SCATTERING.”]"
From: William Happer
To: David Burton
November 13, 2014
Some response are entered below in square brackets and upper case. Thanks for your interest!
From: David Burton
To: William Happer
November 12, 2014
At your UNC lecture you told us many things which I had not known, but two of them were these:
1. At low altitudes, the mean time between molecular collisions, through which an excited CO2 molecule can transfer its energy to another gas molecule (usually N2) is on the order of 1 nanosecond.
2. The mean decay time for an excited CO2 molecule to emit an IR photon is on the order of 1 second (a billion times as long).
Did I understand that correctly? [YES, PRECISELY. I ATTACH A PAPER ON RADIATIVE LIFETIMES OF CO2 FROM THE CO2 LASER COMMUNITY. YOU SHOULD LOOK AT THE BENDING-MODE TRANSITIONS, FOR EXAMPLE, 010 – 000. AS I THINK I MAY HAVE INDICATED ON SLIDE 24, THE RADIATIVE DECAY RATES FOR THE BENDING MODE ALSO DEPEND ON VIBRATION AND ROTATIONAL QUANTUM NUMBERS, AND THEY CAN BE A FEW ORDERS OF MAGNITUDE SLOWER THAN 1 S^{-1} FOR HIGHER EXCITED STATES. THIS IS BECAUSE OF SMALL MATRIX ELEMENTS FOR THE TRANSITION MOMENTS.]
You didn't mention it, but I assume H2O molecules have a similar decay time to emit an IR photon. Is that right, too? [YES. I CAN'T IMMEDIATELY FIND A SIMILAR PAPER TO THE ONE I ATTACHED ABOUT CO2, BUT THESE TRANSITIONS HAVE BEEN CAREFULLY STUDIED IN CONNECTION WITH INTERSTELLAR MASERS. I ATTACH SOME NICE VIEWGRAPHS THAT SUMMARIZE THE ISSUES, A FEW OF WHICH TOUCH ON H2O, ONE OF THE IMPORTANT INTERSTELLAR MOLECULES. ALAS, THE SLIDES DO NOT INCLUDE A TABLE OF LIFETIMES. BUT YOU SHOULD BE ABLE TO TRACK THEM DOWN FROM REFERENCES ON THE VIEWGRAPHS IF YOU LIKE. ROUGHLY SPEAKING, THE RADIATIVE LIFETIMES OF ELECTRIC DIPOLE
November 30, 2024
MOMENTS SCALE AS THE CUBE OF THE WAVELENTH AND INVERSELY AS THE SQUARE OF THE ELECTRIC DIPOLE MATRIX ELEMENT (FROM BASIC QUANTUM MECHANICS) SO IF AN ATOM HAS A RADIATIVE LIFETIME OF 16 NSEC AT A WAVELENGTH OF 0.6 MIRONS (SODIUM), A CO2 BENDING MODE TRANSITION, WITH A WAVELENGTH OF 15 MICRONS AND ABOUT 1/30 THE MATRIX ELEMENT SHOULD HAVE A LIFETIME OF ORDER 16 (30)^2 (15/.6)^3 NS = 0.2 S.
So, after a CO2 (or H2O) molecule absorbs a 15 micron IR photon, about 99.9999999% of the time it will give up its energy by collision with another gas molecule, not by re-emission of another photon. Is that true (assuming that I counted the right number of nines)? [YES, ABSOLUTELY.]
In other words, the very widely repeated description of GHG molecules absorbing infrared photons and then re-emitting them in random directions is only correct for about one absorbed photon in a billion. True? [YES, IT IS THIS EXTREME SLOWNESS OF RADIATIVE DECAY RATES THAT ALLOWS THE CO2 MOLECULES IN THE ATMOSPHERE TO HAVE VERY NEARLY THE SAME VIBRATION-ROTATION TEMPERATURE OF THE LOCAL AIR MOLECULES.]
Here's an example from the NSF, with a lovely animated picture, which even illustrates the correct vibrational mode: http://scied.ucar.edu/carbon-dioxide-absorbs-andre-emits-infrared-radiation
Am I correct in thinking that illustration is wrong for about 99.9999999% of the photons which CO2 absorbs in the lower troposphere? [YES, THE PICTURE IS A BIT MISLEADING. IF THE CO2 MOLECULE IN AIR ABSORBS A RESONANT PHOTON, IT IS MUCH MORE LIKELY ( ON THE ORDER OF A BILLION TIMES MORE LIKELY) TO HEAT THE SURROUNDING AIR MOLECULES WITH THE ENERGY IT ACQUIRED FROM THE ABSORBED PHOTON, THAN TO RERADIATE A PHOTON AT THE SAME OR SOME DIFFERENT FREQUENCY. IF THE
CO2 MOLECULE COULD RADIATE COMPLETELY WITH NO COLLISIONAL INTERRUPTIONS, THE LENGTH OF THE RADIATIVE PULSE WOULD BE THE DISTANCE LIGHT CAN TRAVEL IN THE RADIATIVE LIFETIME. SO THE PULSE IN THE NSF FIGURE SHOULD BE 300,000 KM LONG, FROM THE EARTH'S SURFACE TO WELL BEYOND A SATELLITE IN GEOSYNCHRONOUS ORBIT. THE RADIATED PULSE SHOULD CONTAIN 667 CM^{-1} *3 X 10^{10}
CM S^{-1}*1 S WAVES OR ABOUT 2 TRILLION WAVES, NOT JUST A FEW AS IN THE FIGURE. A BIT OF POETIC LICENSE IS OK. I CERTAINLY PLEAD GUILTY TO USING SOME ON MY VIEWGRAPHS. BUT WE SHOULD NOT MAKE TRILLION-DOLLAR ECONOMIC DECISIONS
WITHOUT MORE QUANTITATIVE CONSIDERATION OF THE PHYSICS.]
(Aside: it doesn't really shock me that the NSF is wrong -- I previously caught them contradicting Archimedes: before & after.)
If that NSF web page & illustration were right, then the amount of IR emitted by CO2 or H2O vapor in the atmosphere would depend heavily on how much IR it received and absorbed. If more IR was emitted from the ground, then more IR would be re-emitted by the CO2 and H2O molecules, back toward the ground. But I think that must be wrong.[YES, THE AMOUNT OF RADIATION EMITTED BY GREENHOUSE MOLECULES DEPENDS ALMOST ENTIRELY ON THEIR TEMPERATURE. THE PERTRUBATION BY RADIATION COMING FROM THE GROUND OR OUTER SPACE IS NEGLIGIBLE. CO2 LASER BUILDERS GO OUT OF THEIR WAY WITH CUNNING DISCHARE PHYSICS TO GET THE CO2 MOLECULES OUT OF THERMAL EQUILIBRIUM SO THEY CAN AMPLIFY RADIATION.]
If 99.9999999% of the IR absorbed by atmospheric CO2 is converted by molecular collisions into heat, that seems to imply that the amount of ~15 micron IR emitted by atmospheric CO2 depends only on the atmosphere's temperature (and CO2 partial pressure), not on how the air got to that temperature. [YES, I COULD HAVE SAVED A COMMENT BY READING FURTHER.] Whether the
Oct. 11, 2024
Markus Ott
ground is very cold and emits little IR, or very warm and emits lots of IR, will not affect the amount of IR emitted by the CO2 in the adjacent atmosphere (except by affecting the temperature of that air). Is that correct? [YES, PRECISELY. WE HAVE BEEN TALKING ABOUT WHAT CHANDRASEKHAR CALLS AN “ABSORBING ATMOSPHERE” AS OPPOSED TO A “SCATTERING ATMOSPHERE.” ASTROPHYSICISTS ARE OFTEN MORE INTERESTED IN SCATTERING ATMOSPHERES, LIKE THE INTERIOR OF THE SUN. THE BLUE SKY DURING A CLEAR DAY IS AN EXAMPLE OF SCATTERING ATMOSPHERE. VERY LITTLE HEATING OR COOLING OF THE AIR OCCURS WITH THIS “RAYLEIGH SCATTERING.”]
Thank you for educating a dumb old computer scientist like me! [YOU ARE HARDLY DUMB. YOU GET AN A+ FOR THIS RECITATION SESSION ON RADIATIVE TRANSFER. ]
Saturation and thermalisation near the ground:
Outside the so-called atmospheric window (wavelength range from approx. 8 to 14μm), the thermal radiation radiated from the Earth's surface has only quite short ranges in the lower atmosphere. In air layers close to the ground, the density of the air is quite high, and the greenhouse gases are strongly diluted with non-IR-active gases (N2, O2, mixing ratio: 1 CO2 molecule to approx. 2500 N2 and O2 molecules).
As a result, greenhouse gas molecules collide here more or less exclusively with non-IR-active gas molecules (order of magnitude 10E10 collisions per sec and molecule). Greenhouse
gases in the excited state are therefore deactivated during collision events with nitrogen or oxygen molecules, before they find the time to emit IR radiation. The IR radiation absorbed here by greenhouse gases is practically completely converted into heat. Therefore, a pronounced back radiation of greenhouse gas IR frequencies from the lower atmosphere is not possible. Here thermalisation is the death of the greenhouse effect, so to speak.
Heat transport by convection:
From the air layers near the ground to the boundary of the troposphere, heat transport is predominantly by convection (Figure 65 and 66).
Thermally excited emission in the upper region of the troposphere:
Due to the low air density at high altitudes, the emission of thermal radiation becomes more important than non-radiative deactivation. Greenhouse gases intensify the cooling of the atmosphere here (Figure 65 and 66
Since the lifetime of the excited state of the 15μm absorption of CO2 is of the order of one second, November 30, 2024
Oct. 11, 2024
Gerald Ratzer
only one photon out of about 100,000 absorbed photons will be re-emitted. If one is careful and calculates with a (0110) lifetime of about 0.1 seconds, about 1/10,000 of the excited states will have the opportunity to emit a photon before it is deactivated by collision with other gas molecules.
Dismantling the CO2-Hoax 2021
- There are two main concepts in climate physics.
- RTC is the Radiation Transfer Concept
- HTC is the Heat Transport Concept
- They are both important and both needed to understand our weather and climate
- Weather and Climate are both very complex systems
- RTC needs an understanding of quantum physics, photons, etc.
- HTC needs a knowledge of the laws of
November 30, 2024
Oct. 11, 2024
Terigi Ciccone