|The emissivity [which also equals absorption] of infrared radiation by CO2 declines with temperature, the opposite of a true blackbody for which the Kirchhoff, Planck, and Stefan-Boltzmann laws apply|
|The emissivity [which also equals absorption] of infrared radiation by water vapor also declines with temperature, the opposite of a true blackbody for which the Kirchhoff, Planck, and Stefan-Boltzmann laws apply|
In a recent lecture, Dr. Robitaille explains the significance of these findings and applicability to CO2 and water vapor:
As Dr. Robitaille demonstrates, Kirchhoff falsely assumed that his law was universally applicable to all materials including non-blackbodies. Since the Planck and Stefan-Boltzmann laws are derived from Kirchhoff's law, they are also applicable only to true blackbodies and cannot be applied to the radiative physics of greenhouse gases.
See also: Is blackbody radiation universal?
This is of course very interesting. However, in an atmosphere Kirchhoff's Law would not apply anyway, because molecules also gain and lose energy by processes other than radiation.ReplyDelete
The oceans are not covered by black asphalt. Instead their surface layer is almost completely transparent to radiation. Hence the ocean surface is not heated by solar radiation alone. Nor is anything on the surface of Earth, let alone Venus where its surface receives less than 10% of the Solar radiation that Earth's surface receives.
The solar radiation reaching Earth's surface (<165W/m^2) would not even raise black asphalt to 235K (let alone 255K or 288K)
Radiation is not the primary determinant of planetary surface temperatures. It is gravity which traps energy, not back radiation, and it's all in my book "Why it's not carbon dioxide after all" from Amazon and iTunes..
You are totally mistaken. Roy Spence, a climate skeptic has listed your theory as one of the most common mistakes made by AGW skeptics.Delete
Gravity is a driver of the lapse rate, which is the rate of change of temperature with altitude. It does not determine the temperature at the bottom of the gaseous atmosphere. This is determined by radiation balance, as well as convection and the transport of latent heat by evaporation from the surface.
False. Surface temperature is determined by equilibrium temp with the Sun + lapse rate from the middle of mass of the atmosphere: 255K + 6.5*5km = 288K.Delete
Bingo - surface temperature determined solely by the barometric formulas, which have absolutely no terms for radiative forcing and are entirely independent of CO2.
Read the posts
Entire 33K GHE is explained solely by atmospheric mass, gravity, pressure, heat capacities.
Your argument unjustifiably ignores radiative transfer without proving its effect is negligible. You are assuming what you claim to prove. You are neglecting the effect of radiation on the lapse rate, rather than proving that it does nothing. You also haven't shown that the effect of additional H2O on the dry adiabatic lapse rate is going to reduce the height at which emission into space takes place. You need to explain why your guesstimates are correct, and the calculations of the GHE in clear air, made by Plass using a computer in the 1950's, which are still accepted by climate scientists as accurate are actually wrong. In addition, you claim by handwaving that additional cloudiness due the the higher WV concentration, would occur and be a cooling effect. In fact the effect of clouds are the most uncertain part of climate models, and observations of clouds indicate that they are a positive feedback.Delete
Your arguments are flawed, and consist merely of hand waving.
1. False, the atmosphere is in radiative/convective equilibrium. Convection easily overcomes any radiative imbalance to restore equilibrium. Read the published paper on radiative/convective equilibrium in this post
2. The equation for the lapse rate is dT/dh = -g/Cp where g = gravity, Cp = heat capacity. There is no term whatsoever in the lapse rate equation for radiative forcing and the lapse rate is completely independent of radiative forcing.
3. The wet adiabatic lapse rate is 1/2 the dry, therefore they effect of additional water vapor is cooling.
4. I've already explained above how the atmospheric temperature profile and surface temperature are determined on all the planets with thick atmospheres. For Earth, surface temperature is determined by equilibrium temp with the Sun + lapse rate from the middle of mass of the atmosphere: 255K + 6.5*5km = 288K. These calculations are completely independent of radiation or "back-radiation forcing"
5. Clouds have a large net negative feedback cooling effect, 6X greater than the alleged [false] warming effect of doubled CO2:
I'm not publishing any more comments from you since they are full of ad homs and against the comment policy.
You comments are devoid of scientific arguments, which you obviously don't have, so you resort to ad homs, inflammatory and abusive comments, and false insinuations.
Simply put, there is no "green house effect", sans a real green house (walls, ceiling, etc). Back radiation cannot heat the source any further. You cannot heat your face by staring into a mirror. If a body, any body, could heat itself via back radiation, then there would be runaway processes happening throughout our universe, and our universe could never have existed in the first place.ReplyDelete
There is no spontaneous creation of energy involved in the greenhouse effect. Energy is arriving at the earth's surface from the sun. When the atmosphere reduces the rate at which energy is radiated back to space below the rate of arrival from the sun, the excess heat is retained by the earth increasing its temperature in areas where the retained heat is located. The earth is not heating itself. The heat has arrived from the sun.Delete
The back radiation greenhouse theory does in fact violate the first & second laws, and requires an impossible reduction of total entropy by assuming heat flows from cold to hot in the lower troposphereDelete
Equilibrium temperature with the sun is 255K. Greenhouse gases cannot warm the earth from 255K to 288K, only atmospheric mass, gravity, and heat capacityDelete
eadler2 - Your comment above is complete nonsense. If the earth does retain heat it does not follow that there is any increase in the temperatures. All that can happen is the temperatures at some point could stay at higher temperatures for longer but there is no increase in any temperature just because heat loss is slowed down. It is easier to see with home insulation but this is not quite the same because we use a thermostat to control room temperatures, with or without insulation. What insulation does is reduce the energy needed to heat the house. It does not and cannot increase the temperature of the heat source. It changes the temperature profile. In the case of the earth, since internal heat is ignored, the heat source is the sun.Delete
Joel Shore is not going to like this.ReplyDelete
You're probably rightDelete
Squidly says "Back radiation cannot heat the source any further", but it can slow down the rate of cooling and that is what I understand to be what is called the "greenhouse effect" in the atmosphere. It is likened to a blanket which stops heat escaping as fast.ReplyDelete
Blankets, greenhouses, and home insulation all work by limiting convection, not by "back-radiative forcing"Delete
The fact is that radiation from the surface of the earth would go out into space with the speed of light if it were not absorbed by greenhouse gases in the atmosphere thermalized, The GHG's will convert the upward radiation into radiation emitted in randomized directions. This inhibits the escape of the radiation directly. What happens is that the radiation emitted to outer space directly occurs at higher elevations and at lower temperatures because of the lapse rate. The redirected radiation maintains the heat contained in the region at and below the earth's surface.
One slight correction;Delete
Blankets and home insulation work (mostly) by slowing the velocity of thermal energy flowing through them (conduction). A man made greenhouse limits convection.
One important consideration when installing home insulation is limiting convection of water vapor into the insulation which reduces it's effectiveness. This is why home builders staple plastic sheets on to the walls of a house (over the insulation) before they put up the "plaster board".
This is all conduction and convection, radiation (back, or otherwise) has a miniscule effect.
Back twenty years ago or so here in the USA you could go to the local hardware store and buy fiberglass insulation that was "foil faced" (i.e. it had a layer of aluminum foil on one side). Allegedly it was more "efficient", however when you do the actual calculations you find out that at the typical temperature differentials (50 degrees F) found when insulating a house the "foil faced" insulation is "useless". Actually it is worse than "useless", the conductive aluminum foil can start fires when commingled with 120 Volt AC wiring, You cannot purchase "foil faced insulation"in the US lately, nobody wants the liability for poor installations.
Indeed with higher temperature differentials (blast furnaces and toaster ovens) reflective insulation (back radiation) can become important, but the concept of "back radiation" is still incorrect.
False most IR absorbed by GHGs is immediately re-emitted with no thermalization. A much lesser amount is thermalized with collisions between CO2/H2O and N2/O2. Inconsequential as far as re-heating the Earth surface however. Convection "short-circuits" & overcomes radiative imbalance in the atmosphere:
Entire 33K GHE is explained solely by atmospheric mass, gravity, pressure, heat capacities.
eadler2 - What do you mean by the "region at and below the earth's surface"? What do you mean by "maintaining the heat"? Is this an alternative the usual "trapped" heat? Heat cannot be trapped or maintained. Heat by definition is the transfer of thermal energy from a hot to a cooler region. Your comment makes no sense.Delete
Derek; the term "slow the rate of cooling" is incorrect in the context of the "greenhouse effect".ReplyDelete
A blanket works by decreasing the velocity at which thermal energy flows through it (versus just air).
IR energy flowing away from the surface departs at the speed of light.
The "rate of cooling" of a surface (via radiation) is determined by the thermal diffusivity of the material below/behind the surface.
The alleged "greenhouse effect" in the atmosphere has no effect on the average temperature of the surface.
Heck a light bulb filament isn't even a "true blackbody", yes the spectral shape approximates the S-B curve, but there are lots of little peaks and valleys. The emissivity of the tungsten varies with wavelength. Even the surface of the Sun (observed outside the Earth's atmosphere) is not a "theoretical black body".ReplyDelete
The S-B theoretical blackbody is a useful construct, but nobody has actually created one, yet.