Why the misdirection on use of TRAPPED when describing the Green House Effect? Is it deliberate?
One
of my biggest complaints is the use of *TRAPPED* when describing the
GHE. Here is an interesting (non-peer reviewed) paper on CO2 physics
explaining just what *trapped* means. Heat is not trapped in the atmosphere, but it is slowed in its escape to space.
Here: http://brindabella.id.au/…/RadiativeDelayInContext170828.pdf
From the abstract:
"Atmospheric Radiative Heat Transfer in Context
Version 170827
© Dai Davies, PhD
dai@brindabella.id.au
REVIEW COPY
Abstract:
It is said that radiative gasses (RGs, or greenhouse gasses) trap heat radiated from the Earth's surface causing it’s temperature to rise by 33 K above the theoretical temperature with no atmosphere. The word ‘trap’ is misleading. RGs delay the radiative transmission of heat from surface to space. I estimate this delay and conclude that its average impact on atmospheric temperatures, the Radiative
Delay Effect (RDE), is in the order of 0.14 [0.1 to 1] K. This result is then placed in the broader context of atmospheric thermodynamics where it complements recent work on the air-surface interaction. The combination leaves no significant role for carbon dioxide...".
Trapped is used in the description of radiative cooling. Radiative cooling is a continuous function starting the instant that the earth is heated from solar radiation. The first step is the release of a photon which is vibrating at that heat frequency when released. So these photons frequecies change with the temperature. Some of these frequencies match with those molecules of certain atmospheric radiative gasses (GHGs), and since they are matching it allows those gas molecules to capture that photon. Capture actually exists for a very short period, typically in the range of a nano second to a micro second, when the vibration of the gas molecule expels a photon at the same frequency as its own heat. That new expelled photon can escape at any angle from the molecule, so that approximately 1/2 of them will return downward toward the earth. The remaining photons expelled toward space will either escape or hit another atmospheric molecule. Escaping to space completes the cooling step. Hitting another atmospheric molecule sill be handled later.
Those returning photons which reach the earth while in the warming phase will usually cool the receiving surface molecule. If the surface is in the cooling phase the returning photon will usually warm the receiving surface molecule. Remembering this is a continuous process, a new photon will be expelled vibrating at the new frequency of the heat of the surface molecule.
Those photons not escaping to space or returning to earth will collide with another atmospheric gas molecule. If that molecule is a GHG the capture release cycle will repeat. Remember there is little or no energy change (heat gain/loss) in the photon.
Most of the atmosphere, ~97% of it, consists of non-GHG gas molecules. In the case of a collision with one of these molecules some energy will be lost by the photon and gained by the non-GHG molecule. Heat is gained in the atmosphere. This step is called conduction, and the heat gained will be reatained for some period much longer than nano/micro seconds. During the period convection occurs causing the now heated molecule to rise in the atmosphere where it will collide with cooler gas molecules. With these collisions energy is again gained and lost by the molecules so that the average temperature of these molecules is lower.
In the end the better trapping of the heat energy is not due to radiative transfer, but due to conduction. Radiative transfer does have an additive effect to warming the atmosphere by reducing photon release to space compared to if these GHGs weren't resident in the atmosphere.
They do not <b>trap</b> heat energy in the atmosphere, they do slow its release to space, but in doing that allows the atmospheric heat to be increased in the non-GHG molecules of the atmosphere, and have some momentary effect on surface heating.
Here: http://brindabella.id.au/…/RadiativeDelayInContext170828.pdf
From the abstract:
"Atmospheric Radiative Heat Transfer in Context
Version 170827
© Dai Davies, PhD
dai@brindabella.id.au
REVIEW COPY
Abstract:
It is said that radiative gasses (RGs, or greenhouse gasses) trap heat radiated from the Earth's surface causing it’s temperature to rise by 33 K above the theoretical temperature with no atmosphere. The word ‘trap’ is misleading. RGs delay the radiative transmission of heat from surface to space. I estimate this delay and conclude that its average impact on atmospheric temperatures, the Radiative
Delay Effect (RDE), is in the order of 0.14 [0.1 to 1] K. This result is then placed in the broader context of atmospheric thermodynamics where it complements recent work on the air-surface interaction. The combination leaves no significant role for carbon dioxide...".
Trapped is used in the description of radiative cooling. Radiative cooling is a continuous function starting the instant that the earth is heated from solar radiation. The first step is the release of a photon which is vibrating at that heat frequency when released. So these photons frequecies change with the temperature. Some of these frequencies match with those molecules of certain atmospheric radiative gasses (GHGs), and since they are matching it allows those gas molecules to capture that photon. Capture actually exists for a very short period, typically in the range of a nano second to a micro second, when the vibration of the gas molecule expels a photon at the same frequency as its own heat. That new expelled photon can escape at any angle from the molecule, so that approximately 1/2 of them will return downward toward the earth. The remaining photons expelled toward space will either escape or hit another atmospheric molecule. Escaping to space completes the cooling step. Hitting another atmospheric molecule sill be handled later.
Those returning photons which reach the earth while in the warming phase will usually cool the receiving surface molecule. If the surface is in the cooling phase the returning photon will usually warm the receiving surface molecule. Remembering this is a continuous process, a new photon will be expelled vibrating at the new frequency of the heat of the surface molecule.
Those photons not escaping to space or returning to earth will collide with another atmospheric gas molecule. If that molecule is a GHG the capture release cycle will repeat. Remember there is little or no energy change (heat gain/loss) in the photon.
Most of the atmosphere, ~97% of it, consists of non-GHG gas molecules. In the case of a collision with one of these molecules some energy will be lost by the photon and gained by the non-GHG molecule. Heat is gained in the atmosphere. This step is called conduction, and the heat gained will be reatained for some period much longer than nano/micro seconds. During the period convection occurs causing the now heated molecule to rise in the atmosphere where it will collide with cooler gas molecules. With these collisions energy is again gained and lost by the molecules so that the average temperature of these molecules is lower.
In the end the better trapping of the heat energy is not due to radiative transfer, but due to conduction. Radiative transfer does have an additive effect to warming the atmosphere by reducing photon release to space compared to if these GHGs weren't resident in the atmosphere.
They do not <b>trap</b> heat energy in the atmosphere, they do slow its release to space, but in doing that allows the atmospheric heat to be increased in the non-GHG molecules of the atmosphere, and have some momentary effect on surface heating.
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