Pyrgeometers work using a thermopile which generates a current when one side gets hotter than the other. They shield both sides but leave an infrared 'window' on the other side. If infrared light comes in, it gets hotter and it gives an output. It only gives you an output if there's infrared light coming in, it's a direct measurement and it also gives you the direction of the net flow.
But pyrgeometers aren't all, we can use gadgets called 'Fourier Transform Infrared Spectrometers' to split apart the different wavelengths of light and measure them separately.
This has been done over and over again and it shows the greenhouse effect and back radiation are real.
https://ams.confex.com/ams/Annual2006/te...
Seems to be some weird gobbledigook about clouds too. More aerosols provide more nuclei and mean that the average cloud droplet is smaller. Thunderclouds are so thick that the light doesn't get through anyway, that's why they look grey from below. Their droplet size isn't that important.
For other clouds, smaller droplets make them reflect more light. The calculations are done using Mie theory or geometric optics.
http://en.wikipedia.org/wiki/Mie_scatter...
For water droplets, the probability that light is scattered by a droplet is related to the 'cross section' of the droplet (which is pi times the radius squared).
Bigger droplets mean that each one has a bigger chance of causing scattering. If you make the droplets twice as wide, then the cross section and therefore the chance of scattering goes up by a factor of 4.
But if you make the droplets smaller, you get more droplets out of your water. Volume is (4/3) times pi times the radius cubed: so if you double droplet size you get 8 times fewer droplets.
Each one is a weaker scatterer, but there are lots more of them and this effect is more powerful. So aerosols make clouds 'brighter' and so they reduce the sunlight reaching the surface and cool it a bit.
This was found very neatly over Texas and the US southwest: changes in temperature followed changes in aerosols.
http://earthobservatory.nasa.gov/IOTD/vi...
" An IR optical pyrometer measures the proportion of vibrational activated emission sites, a function of temperature."
Wrong. An IR optical pyrometer works by heating a wire to a known temperature and comparing the color of the wire to the color of the object whose temperature is unknown. It has nothing to do with the proportion of "vibrational activated emission sites" (a phrase which has no meaning and is grammatically incorrect anyway).
http://en.wikipedia.org/wiki/Pyrometer#P...
"However. this is not a real energy flux but the potential energy that the emitter would transfer to a sink at absolute zero."
That is wrong. It is a real energy flux and can be measured. Even Roger Pielke doesn't argue that the longwave flux is an imaginary quantity:
http://pielkeclimatesci.files.wordpress.com/2010/11/pielke_2010-11-1_-gcmflux-midlat-fig1.jpg
My radiation physics is a bit rusty haven't used any of that math for 36yrs, so not going to try now. But in simple terms what is being said about back radiation makes sense and your post doesn't. Any green house gas acts as an insulator on the planet. It does not create energy, it simply reduces the flow of energy through it, thus creating a new quasi equilibrium once the planet has warmed enough to again be able to radiate out all the incoming energy.
The premise of your post is that adding an insulator [GHG] will not retain more energy on the planet. Sorry but that fails at the first hurdle of common sense. No need to fight through the pretended science.
Have you ever walked next to a building and felt warm, and yet you touched the building, and it felt cool to the touch. If you have, you have experienced back radiation.
edit
The joannenova article is nothing but a bunch of ad homs against Michael Brown.
I read the question as black radiation and I was pretty confused for a while. I think it is time for a new prescription.
Very interesting post by turnedoutnice. We didn't learn about much atmospheric physics in geology.
I like what this poster added later also :
"The IPCC has yet again tried to pull off an immense hoax by packaging it inside a pseudo-scientific report.
They did this 6 years ago with AR4 which had at its heart the claim that aerosols ‘making clouds more reflective’ hid CO2-AGW. To do this they substituted Sagan’s incorrect aerosol optical physics for Twomey’s more correct version when he had warned there was an unknown second optical effect.
This is large droplets in rain clouds scattering light much more effectively than small droplets – it’s why thunderclouds are very dark underneath and why Venus has high albedo. This is why Sagan got the Venusian atmosphere wrong and started the CO2-AGW scare for us.
This time the IPCC is trying to scare us with the ocean heat content argument. The claim that this is from the extra ‘back radiation’ from more CO2 is the scientific equivalent of ******** because IR causes more evaporation, not temperature rise.
In reality, the extra ocean heating has been from the burst of Asian aerosol pollution making clouds less reflective so more SW energy enters the oceans and it is SW that does the heating.
Correct the physics mistakes and there is virtually zero CO2-AGW and the aerosol effect has stabilised hence no more warming. Don’t let this intergovernmental posse of confidence tricksters and their unscientific hacks fool you yet again."
It invites the question : "Will the real AGW culprit please stand up and be recognized?" Arrhenius would be proud I think!
I have heard this term often and believe it is a necessary component of CO2 induced warming including water vapor feedback. However, I just read a comment on an unrelated post as follows:
"Sorry, but you are clearly one of the 97% of scientists and engineers who fail to understand radiative physics. An IR optical pyrometer measures the proportion of vibrational activated emission sites, a function of temperature. The pyrgeometer calculates the radiation field of a body with that temperature and outputs this in Power units, W/m^2, which assumes a collimated beam.
However. this is not a real energy flux but the potential energy that the emitter would transfer to a sink at absolute zero. The Kiehl – Trenberth energy budget makes this mistake and introduces an entirely artificial 333 W/m^2 ‘back radiation’, a perpetual motion machine of the 2nd kind with the lower atmosphere causing itself to expand.
To offset this they falsely claim Kirchhoff’s Law of Radiation applies at ToA resulting in the ‘Clear Sky Atmospheric Greenhouse Factor’ of 157.5 W/m^2, 6.85 times higher than the real atmospheric IR absorption of 23 W/m^2. This extra warming causes more evaporation in the models by pretending the ‘back radiation’ causes more evaporation.
During hind casting, they use double real low level optical depth to pretend to get the correct temperature. It’s a confidence trick and you are one of those who has fallen for it. Sorry, but these are the facts, not the glittering claims of fake physics." http://joannenova.com.au/2013/09/michael-brown-astronomer-says-science-is-not-about-debate-the-people-are-too-stupid/#comment-1322091
That seems like a pretty well constructed takedown of this so-called "back radiation". What holes can you poke in the above argument?
My radiation physics is a bit rusty haven't used any of that math for 36yrs, so not going to try now. But in simple terms what is being said about back radiation makes sense and your post doesn't. Any green house gas acts as an insulator on the planet. It does not create energy, it simply reduces the flow of energy through it, thus creating a new quasi equilibrium once the planet has warmed enough to again be able to radiate out all the incoming energy.
The premise of your post is that adding an insulator [GHG] will not retain more energy on the planet. Sorry but that fails at the first hurdle of common sense. No need to fight through the pretended science.
Have you ever walked next to a building and felt warm, and yet you touched the building, and it felt cool to the touch. If you have, you have experienced back radiation.
edit
The joannenova article is nothing but a bunch of ad homs against Michael Brown.
I read the question as black radiation and I was pretty confused for a while. I think it is time for a new prescription.
Very interesting post by turnedoutnice. We didn't learn about much atmospheric physics in geology.
I like what this poster added later also :
"The IPCC has yet again tried to pull off an immense hoax by packaging it inside a pseudo-scientific report.
They did this 6 years ago with AR4 which had at its heart the claim that aerosols ‘making clouds more reflective’ hid CO2-AGW. To do this they substituted Sagan’s incorrect aerosol optical physics for Twomey’s more correct version when he had warned there was an unknown second optical effect.
This is large droplets in rain clouds scattering light much more effectively than small droplets – it’s why thunderclouds are very dark underneath and why Venus has high albedo. This is why Sagan got the Venusian atmosphere wrong and started the CO2-AGW scare for us.
This time the IPCC is trying to scare us with the ocean heat content argument. The claim that this is from the extra ‘back radiation’ from more CO2 is the scientific equivalent of ******** because IR causes more evaporation, not temperature rise.
In reality, the extra ocean heating has been from the burst of Asian aerosol pollution making clouds less reflective so more SW energy enters the oceans and it is SW that does the heating.
Correct the physics mistakes and there is virtually zero CO2-AGW and the aerosol effect has stabilised hence no more warming. Don’t let this intergovernmental posse of confidence tricksters and their unscientific hacks fool you yet again."
It invites the question : "Will the real AGW culprit please stand up and be recognized?" Arrhenius would be proud I think!
I have heard this term often and believe it is a necessary component of CO2 induced warming including water vapor feedback. However, I just read a comment on an unrelated post as follows:
"Sorry, but you are clearly one of the 97% of scientists and engineers who fail to understand radiative physics. An IR optical pyrometer measures the proportion of vibrational activated emission sites, a function of temperature. The pyrgeometer calculates the radiation field of a body with that temperature and outputs this in Power units, W/m^2, which assumes a collimated beam.
However. this is not a real energy flux but the potential energy that the emitter would transfer to a sink at absolute zero. The Kiehl – Trenberth energy budget makes this mistake and introduces an entirely artificial 333 W/m^2 ‘back radiation’, a perpetual motion machine of the 2nd kind with the lower atmosphere causing itself to expand.
To offset this they falsely claim Kirchhoff’s Law of Radiation applies at ToA resulting in the ‘Clear Sky Atmospheric Greenhouse Factor’ of 157.5 W/m^2, 6.85 times higher than the real atmospheric IR absorption of 23 W/m^2. This extra warming causes more evaporation in the models by pretending the ‘back radiation’ causes more evaporation.
During hind casting, they use double real low level optical depth to pretend to get the correct temperature. It’s a confidence trick and you are one of those who has fallen for it. Sorry, but these are the facts, not the glittering claims of fake physics." http://joannenova.com.au/2013/09/michael-brown-astronomer-says-science-is-not-about-debate-the-people-are-too-stupid/#comment-1322091
That seems like a pretty well constructed takedown of this so-called "back radiation". What holes can you poke in the above argument?
