Roy Spencer returns to the "The Issue of Backradiation" in More Musings from the Greenhouse with statements like:
- The existence of this “back radiation” is disputed by some people because of two seemingly counter-intuitive features.
- Imagine two plates at two different temperatures facing one another. Let’s say one plate is at 100 deg. C and the other is at 0 deg. C.
- But now imagine that the cooler plate is nearly the same temperature (99 deg. C) as the hotter plate (100 deg. C). It will be obvious to most people that the net flow of IR energy from the 100 deg. C plate to the slightly cooler plate will be at a slower rate than it was before.
- But why should that be? In both cases the 100 deg. C plate is emitting IR at the same rate, yet the NET flow of IR is reduced if the cooler plate is not as cold.
When I ask in a comment what the scientific evidence Roy has for his proclamation that "in both cases the 100 deg. C plate is emitting IR at the same rate", I get the following answer:
- Yes, Claes you found me out. I have nefarious motives for using certain terminology. It’s simply to annoy you.
This is more than musing, it is nefariously amusing, with nefariously meaning "extremely wicked" or "extremely morally bad in principle or practice".
When I ask Roy to get serious, I get no response.
I ask him here again to get serious and answer my question: What is the scientific evidence Roy, supporting your proposition that emission of IR energy is independent of the surrounding temperature? You can reply as a comment to this post. I am serious.
PS Follow the debate as comments to Roy's post, and see how backradiation is deconstructed into the wardrobe of scientific ghosts.
Inlägg
Since I am not a mathematician or a physicist, I try to think in pictures. Two communicating buckets gives a large flow of the height difference is large and smaller at the small difference. The effluent from the higher bucket decreases due to the resistance of the tube. Analogously, in the case of irradiation as described should there be a resistance to a "medium" in which radiation is transmitted and which exerts a certain resistance to the flow that increases with the temperature difference.
SvaraRaderaMichelson / Moore?
Yes this is a reasonable physical model.
SvaraRaderaThe two "communicating buckets" could well be a water tank in a roof connected to a wash basin beneath it. The water flow rate F will be proportional to the head of water (i.e. the height difference) H and the resistance of the connecting pipe, R, such that F = H/R (exactly analogous to electrical current flow I = V/R).
SvaraRaderaA Deluge alarmist, however, would probably say that the flow of water out of any container of water is dependent on its absolute height above ground level (or maybe above the centre of the earth), and if the absolute height of water tank is 1000 metres, and the absolute height of the wash basin is 990 metres, and R=1, then water flows out of the tank at a rate 1000, and out of the washbasin at a rate 990, and the net flow is 1000-990, or 10. And that in the connecting pipe there is a downward water flow of 1000, and simultaneously an upward backflow of 990. And if you were able to prevent this upward backflow from occurring (by introducing a one-way valve into the pipe), water would come out of the tap at the rate 1000 rather than 10, i.e. 100 times faster, and a "Deluge". Even the slightest restriction of water flow in the pipe will have enormous effects.
It's a bit like having two connected horses pulling in opposite directions with almost equal force, so that there is only slight net movement in one direction. But if one horse stops pulling, the other horse will gallop away at high speed.
And this how AGW alarmists see radiative heat flow in the atmosphere. It's all only just in balance, and even a small change will result in "runaway" global warming (or cooling). Even the slight restriction caused by small amounts of CO2 in the atmosphere is enough to cause catastrophe
That is right Frank, with this kind balance you can create alarm out of nothing, if this is your objective.
SvaraRaderaThis is why backradiation is so popular among alarmists. But why does a non-alarmist like Roy embrace this fiction?
Maybe it's not that they _want_ to create alarm, but that the way they think about radiative heat flows leads them to become alarmed. The alarm is a logical consequence of the physical model they are using.
SvaraRaderaAfter all, if I thought that water flowed out of a tank in proportion to its absolute height alone, then I would see two connected water tanks as both having water flowing out of them, with the net flow being one flow subtracted from other, and a flow and a backflow. Logic demands it. And if this is what is imagined to happen in pipes, then there would be water flowing up one half of a pipe, and water flowing down the other half. But nobody seems to think that this is what is actually happening in water pipes (as far as I know!), and this because water is physical stuff which is likely to collide with water coming in the opposite direction, and so is implausible/impossible.
But in the case of radiative heat loss, which is regarded as being proportional to the fourth power of the absolute temperature of a body, the notion of backradiation doesn't seem as implausible as the backflow of water because photons aren't able to bump into each other (as far as I know) as they go past one another. How big and how heavy is a photon? Is it at all comparable to a water molecule? Has anyone ever seen a photon?
And since they see radiative heat transfer in this way, they can also see that it's inherently unstable, and can "flip" very quickly. Their model forces them to become alarmists. Perhaps the real question should be: Given he shares the same physical model, why isn't Roy Spencer an alarmist too?
Frank Davis:
SvaraRaderaThank you. Liked the horses.
Claes Johnson:
The Ether is missing. Is it enough to reevaluate the old Michelson–Morley experiment or is new experiments needed.
Yes I saw your calculations but couldn't follow.
Yes, incorrect math and physics can be dangerous: it may send alarm when there is no reason and miss to send alarm when there is reason. I am not convinced that alarmists have simply been misled by incorrect physics without any alarmist inclinations. I think it is a coupled problem where alarmism goes hand in hand with incorrect physics and which comes first is impossible to clear out, and maybe is not so interesting either.
SvaraRaderaElectromagnetic waves need ethers to for propagation. My idea is that there are many ethers depending on your velocity as observer. I develop this in Many-MInds Relativity:
SvaraRaderahttp://www.csc.kth.se/~cgjoh/ambsrelativity.pdf
Claes: The "one way emission theory" has been discussed many times in this and many other blogs and has been shown to produce absurd results. Why is it so important to keep a theory which so obviously is false. Because of the second law of thermodynamics?
SvaraRaderaThe AGW-alarmism can be fighted against by other means.
The two-way theory is incorrect physics and as such potentially very dangerous, as are all beliefs about reality which are grossly incorrect.
SvaraRaderaAnd still, it is the one-way theory that produces the unreasonable results, like zero emission/radiation within a closed blackbody.
SvaraRaderaWhich scientist said that and where?
SvaraRaderaIt follows from the one-way theory. The net radiation is zero from all parts inside.
SvaraRaderaAs I understand it, Dr. Spencer is saying two parallel plates, one hotter than the other, the hotter will get warmer still?
SvaraRaderaIs this assuming a constant power source?
Wouldn't it require more wattage to maintain the same temperature if a cold object is placed next to the hotter one since the heat will transfer from hot to cold?
A computer CPU uses a heat sink. It doesn't slow the cooling of the CPU by conduction obviously. Once at equilibrium, in order to raise the temperature of the CPU surface, work must be performed which requires an increase of wattage which translates into more heat generated; temperature rises. If a large gap is present instead, the CPU will rapidly warm. Would decreasing the gap cause the CPU to get warmer still? Removal of the heat sink completely would cause the CPU to burn up (in most cases), and not securely attached will cause the CPU to get much warmer, but I fail to see the logic that placing the heat sink closer would cause the CPU to get warmer still.
I would think a simple experiment should settle the issue. Surely an array of thermocouples to measure whether a hot plate will get hotter still if cold plate is placed next it.
Surely a heat transfer simulation software product would get it right? No?
Anonym, there is no constant power source, just two plates with starting temperatures.
SvaraRaderaI think Dr S tries to convince some people that there is a two way energy transfer by radiation between bodies with different temps. That´s what back radiation is about.
Hi Claes,
SvaraRaderaPlease allow me to give you an explanation to your question: Why Is Roy Spencer Not Serious?
I used to follow Dr Roy Spencer’s blog with great interest until the time he made that ‘Yes, Virginia, there is back radiation’ post on his blog. Since then I stopped.
Let’s look at the events leading up his post, and him making up his mind that he has discovered ’back radiation’ the climate scientists equivalent of the alchemist ‘lodestone’ turning lead into gold.
A short time before this post Roy bought an IR temperature reading instrument. He posted how overjoyed and happy he was with this new kit. He went outside, pointed the instrument at the night skies and measured the heat radiated from the cold dark skies, the back-radiation that climate change scientists put in their models. A blogger told him that he was not measuring the night skies but the temperature of the dense air layer above his house, but he ignored that. His couple of hundred dollars worth of kit manufactured in the China, can do things better that million dollar satellites!
He then wandered indoors, and pointed his instruments at various things in his house. (Notice how of late he measured the inside of his fridge and freezer; the cat must be fed-up by now.) He sat down, and pointed the instrument at his electric bar heater. He recorded a temperature of 200˚C when the instrument was pointed directly on the heating bar; interesting so far. He then moved a cold piece of metal, he described it as a metal bar, in front of the electric bar heater and then recorded the temperature of the heating bar at 250˚C. So there you are; he proved back radiation. The cold steel bar was radiating heat back at the heating element and the temperature of the heating bar increased by 50˚C. An Eureka moment of pure joy, a scientific breakthrough, his name will be passed down from generation to generation as the man that showed the whole world how back radiation can be demonstrated!
When I read his blog I was surprised that a supposedly clever man of science can be so naive!
I can remember the old fashioned heating bars that had exposed wires wound around a ceramic rod. When the heater is turned on the whole wire starts to glow, first in the centre, then spreading out towards the ends, until the whole wire is a red, almost yellow, colour, and the heat radiation from the coil spreads through-out the room. We did not have an IR instrument to measure the temperature of the wire, but I can remember one of my uncles holding up a cigarette to the heater, touching the wires, to light it. Those open wire electric bar heaters are not sold anymore as they are just too dangerous. It is too easy to start a fire if clothing is hung up to dry in front of it.
The modern version of the electric bar heater has the heating coil covered by a ceramic, almost glass like cylinder. The heating wires are shielded from the users by this outer cover. The outer temperature of this bar heater is controlled by two factors: the amount of heat generated by the inner heating element, and the rate at which the ceramic cover can get rid of the heat. Put the heater in a big hall, or outdoors, with some wind blowing or a draft, and the ceramic outer cylinder will dissipate heat so quickly that it will not be as bright, a sign of how hot it is, as when left inside in a smaller room.
An electrical/heating and ventilation engineer will be able to explain to Roy why he measured what he observed, and also explain that blocking a heater is bad practice as you will eventually blow the thing up!
Ok, just two plates with starting temperatures. Does the gap between them matter? Can too small a gap introduce conduction? What is the ideal gap to perform such a test?
SvaraRaderaLet me understand this. Dr. Spencer claims there will be a slower cooling rate of the hot plate?
The hot plate (373 deg K) will have a slower cooling rate if the background has a high temp (372 deg K) than if it has a low temp (273 deg K). Isn´t that logical to you? Perhaps I misunderstand you. Just think of energy loss by radiation, no conduction involved.
SvaraRaderaThis person says he did an experiment to show back radiation in action. Apparently there is much disagreement on this matter. The other person did a different experiment and says there was no slowing of the cooling rate while taking temperature measurements. It seems they are checking too different things.
SvaraRaderahttp://www.drroyspencer.com/2012/02/yes-virginia-the-vacuum-of-space-does-have-a-temperature/#comment-35194