The evidence of Downwelling Longwave Radiation put forward by CO2 alarmists is that an IR-detector of some sort when pointed to the sky gives a reading which is not zero, and the non-zero reading is used as evidence that something has been recorded, which is then interpreted as DLR or backradiation from the cold sky to the warmer surface of the Earth.The evidence of DLR is thus a non-zero reading of an IR-detector.
Suppose now, to turn the argument around, that the reading of the IR-detector is zero. That would be the case if the IR-detector works by detecting a temperature difference and if the temperature difference happens to be zero. This would be the case if the temperature of the Earth is equal to the temperature of the sky. The IR-detector working on a principle of
temperature difference, like a thermocouple, would then record zero, as if nothing was recorded.
The following questions present themselves:
- What could be concluded from a zero reading of an IR-detector?
- That there is positive DLR?
- That there is positive DLR precisely balanced by Upwelling Longwave Radiation?
- Or can nothing positive be concluded from a zero reading?
Inlägg
"What could be concluded from a zero reading of an IR-detector?"
SvaraRaderaIt's broken.
An IR detector that read zero when looking at something with a non-zero temperature would be a pretty worthless IR detector. An IR detector reading of zero (assuming this isn't some calibration error) should mean it is seeing zero incoming infrared energy, i.e. it is being completely shielded from all IR radiation.
SvaraRaderaA thermocouple reads zero if there is no temperature difference, and thus the detector will read zero if it is looking at an object of the same temp as it's own.
SvaraRaderaDoes the zero reading indicate zero temperature? Does the zero reading indicate
that there is a two-way canceling transfer of heat energy? If yes, how big is
the two-way flow? is it determined by the zero reading?
Claes, do you think that if the "greenhouse" gases around the earth had the same temperature as the earth surface, should this stop the radiation of IR from the earth. (The net radiation will be zero.)
SvaraRaderaA thermocouple is not an IR detector.
SvaraRaderaBut a common IR detector uses a thermocouple for detection.
SvaraRaderaClaes is correct and IR instrument uses a thermocouple or thermopile or other temperature measuring device which directly measures a voltage or current (eg resiatance thermometer which requires a battery). If the device is pointed at aniert object eg a statue which is at the same atmospheric temperature as the device the reading should be zero. If it is not then the output reading needs to be corrected back to zero. That is the first check anyone should do, ie correct the zero. Next the device needs to be calibrated for some known temperatures and emissivities. In pottery supply shops you can get cones which melt in a very small standard temperature range. Pottery kilns are good for learning about heat transfer. You can measure the fuel input (natural gas or LPG), you can adjust the burner, you can make it oxidising or reducing, you can measure the temperature and flow of the exhaust, you can measure the temperatures at various points, you can sight the ware and the temperature cones etc.
SvaraRaderaFinally, if you then study some engineering textbooks about heat transfer and do some calculations using your measurements from the pottery kiln you may just begin to realise what little physicists and climate scientists understand about heat transfer. (note- energy in must equal energy out & heat energy can only transfer from high temperature to low temperature) (also note as Nobel prizing winning physicist WE Lamb Jr has written in peer reviewed articles -photons do not exist, e-m energy from X-rays through IR, Microwaves & radio waves have a wave form which can be amplified or cancelled)
keep strang cementafriend
Incorrect. If you want to measure temperature differences, you can use a thermocouple. If you want to measure IR radiation, you can't. I don't think potters can give physicists many lessons in heat transfer.
SvaraRaderaAnonym @03:52 you clearly have no knowledge about heat transfer and clearly have never made any measurements. IR radiation can not be measured, it can only be calculated (eg the S-B equation) with some assumptions (eg emissivity of natural gas flame =0.45) which may not give the correct result because of turbulence and convective heat transfer (the latter is something no physicist has even the slightest understanding).
SvaraRaderaIf you can read I said "Pottery kilns are good for learning about heat transfer". I did not say that potters necessarily understand what and why things happen when a ceramic item is being fired but I can say that those climate scientists who pretend they know physics will not understand what happens in a pottery kiln.
In politeness I wish you good health and hope that you can learn something from Claes.
cementafriend
"IR radiation can not be measured"
SvaraRaderaWilliam Herschel managed it, more than 200 years ago. He did not need the Stefan-Boltzmann equation, firstly because it had not been formulated, and secondly because it is irrelevant to the detection of IR. Nor did he make any assumptions. He simply detected it directly. Have humans somehow become unable to do so since then?
To directly detect IR heating without directly detecting an increase of temperature is probably impossible.
SvaraRaderaThis post is very bizarre. Any functional IR detector with sufficient sensitivity pointed at the sky on a cloudless night will detect thermal emission from the atmosphere. The question of what a non-detection would mean is a retarded one.
SvaraRadera