Visible Greenhouse Gases

[Richard111]

I was running Bing on "heat trapping greenhouse gases" and this turned up.

I suppose it had to happen. Look at the video on the first page and I quote the reason for this wonderful technology from the bottom of the second page.

Anyone care to bet how long before the BBC has one these cameras?


Greenhouse Gases: Seeing the Unseeable with 'Gas Finder' FLIR Cameras

Quote:On a walk through their plant to see how FLIR cameras are made, we asked them if - given global negotiations to regulate carbon dioxide – if anyone has requested a CO2 camera for commercial use.

"No one's asked us for one," said Benson.

Not yet, but global negotiations aiming to make it finally no longer free to put emit CO2 into the air may soon have FLIR's full attention.

[Questioning_Climate]

Richard111:

Thanks for sharing that. It is certainly an interesting piece, and the bit at the end referring to Hansen was a good laugh.

It was not clear from the article whether FLIR has invented some kind of technology variant or were using their standard equipment. I was not particularly impressed by the video because I have access to one of their cameras and the effects they show require high concentrations of gas. Several of the observations are similar to mirage effects that can be seen in any turbulent gas entering another of a different temperature. Gas leaks are generally, if not always, a different temperature to the surroundings.

To make good thermal measurements from the camera corrections need to be applied for the effect of humidity. Hot exhaust gases are very high in water vapour and we know it shares and dominates most of the IR spectrum. Similarly, the Arctic methane probably has a high level of water vapour relative to the background air.

If a camera of this type is to be used to detect any specific gas then it will be to be tuned to a fingerprint band that is not covered by other gases. Basically, it will have problems akin to those used at MLO for CO2 in terms of separating out the influence of water vapour and other IR responsive gases.

[Richard111]

Thanks for the comments Q_C. Food for thought.
When I looked at the video I did wonder how the camera could "see" CO2. I was thinking along the lines of a double image, one for normal colour, and then a filtered IR image overlaid after colour shifting.
Hell, I don't even know how an IR camera captures images.

[Questioning_Climate]

Examples of the camera spectral responses:

Quote:Spectral range:
FLIR T250 (R&D) = 7.5-13 μm
FLIR GF320 (Gas Leak type) = Cooled InSb / 3–5 μm

Whilst the gas leak type is probably best for the detection of CO2, it is still susceptible to the influence of CH4, H2O, O2/O3, N2O, etc. It will also 'image' the emissions temperature.

---

Richard111,

The cameras usually have 3 "realtime" viewing modes. They give standard (optical) picture like you'd expect from a domestic video camera; a thermal only image; and an overlaid optical and thermal image. Some allow sophisticated combinations such as optical with selected box for thermal.

Interpretation of the images needs great care. For example you could have a thick piece of copper that is half shiny and half blackened apparently reading very different temperatures even though the copper is isothermal. That is simply the result of differences in surface emissivity. Another common problem is reflections. Body heat and lighting - yes even fluorescents - can reflect and give spurious heat images.

One of our party tricks is to stand in front of a glass window and point the camera at it. You can view the window with the IR camera in optical mode and you see straight through. If you switch to thermal you can see almost nothing but your own reflection.

[Richard111]

Spectral range:
FLIR T250 (R&D) = 7.5-13 μm
FLIR GF320 (Gas Leak type) = Cooled InSb / 3–5 μm

And CO2 spectra is?? Never mind, the camera records hot gases. Good enough for greenies I guess.

[Derek]

Hot (exhaust) gases and steam so often portrayed as "man's pollution" that is supposedly "killing the planet".
How many times have we seen this "picture". ?

AGW is becoming so transparent, for what it actually is.
Hot air, nothing more.