post wuwt 31/1/13

<i>Konrad says: January 30, 2013 at 1:57 pm   thefordprefect,  I note in your IR imaging that while water vapour does not read at 100C is is still slightly visible, reading 28C.</i> ——- Looks as if blogger has lost the videos one showed Steam at 28C rising from the boiling water – the still is from the same run ——– <i>Experiment 1. (low cost)  Build two insulated containers with potassium chloride salt lenses for lids. Under a clear dry night sky (desert conditions would be best) fill both containers with dry 30C gas. CO2 in one container 1, N2 in container 2. Which container cools Faster? Is the answer – A. Both containers cool at the same rate.  B. Container 1 cools faster because of the greater IR emission from CO2.  C. Container 2 cools faster because of the greater thermal conductivity of N2</i> ——– This is not a good experiment as you describe it: the insulated walls/salt winow will be heated by the gas to gas temperature. These will then radiate in all directions, with BB radiationprofile, eventuall passing the window to space. same for both boxes. The CO2 will additionally radiate at specific wavelengths but the large proportion of escaping radiation will be from the warm insulation/salt. the CO2 will additionally intercept some of the wavelengths from the walls of the box/window preventing this escaping The hot Co2 will radiate in all directions. this wold reduce the radiation escaping at the absorption frequencies.

I think i would suggest that the CO2 gas will cool slower.    ——— <i> Experiment 2. (high cost)  Attach two gas cylinders with regulators one CO2, one N2, to two 10m long lengths of 5mm PVC tubing. Coil most of the tubing through an insulated container full of hot water. Attach the two open ends of the PVC tubes to two retort stands in front of a cool wall. Set gas flow from both tubes to 1 L/s. Observe the gas flowing out of both tubes with a high quality IR camera capable of seeing beyond 15um. Are the results – A. Both tubes are visible as warm, but both gas plumes are undetectable.  B. Both tubes are visible as warm and the CO2 gas plume is also visible</i> ————— both tubes will be visible at same temperature. N2 will be invisible. CO2 will show up as warm plume but on a camera adjusted for BB radiation the temp will be much less than the actual temp.. ————-   <i>Or perhaps this –  “What would happen to convective circulation in the lower atmosphere if the atmosphere contained no radiative gases?”</i>

Convection does not depend on ghgs. The ground would radiate as a BB and the lw radiation would all escape without absorption with no ghgs. The ground/sea transfers heat (conducts) from/to the non ghg atmosphere and eventually equilibrium will be reached when radiation from the ground = radiation from the sun. the ground temp will be the same as the lowest layer of atmos temp and presumably the amos will cool at adiabatic lapse rate from this temp

http://wattsupwiththat.com/2013/01/28/matt-ridley-a-lukewarmers-ten-tests/#comments

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One Comment

  1. Posted 2013/01/31 at 12:26 | Permalink | Reply

    post failed!
    try again:

    By logging in you’ll post the following comment to Matt Ridley: A Lukewarmer’s Ten Tests:
    Well the “open site” of WUWT is not!
    I posted this from my home IP address and it got binned!

    Konrad says: January 30, 2013 at 1:57 pm thefordprefect, I note in your IR imaging that while water vapour does not read at 100C is is still slightly visible, reading 28C.
    ——-
    Looks as if blogger has lost the videos one showed Steam at 28C rising from the boiling water – the still is from the same run
    ——–
    Experiment 1. (low cost) Build two insulated containers with potassium chloride salt lenses for lids. Under a clear dry night sky (desert conditions would be best) fill both containers with dry 30C gas. CO2 in one container 1, N2 in container 2. Which container cools Faster? Is the answer – A. Both containers cool at the same rate. B. Container 1 cools faster because of the greater IR emission from CO2. C. Container 2 cools faster because of the greater thermal conductivity of N2
    ——–
    This is not a good experiment as you describe it: the insulated walls/salt winow will be heated by the gas to gas temperature. These will then radiate in all directions, with BB radiationprofile, eventuall passing the window to space. same for both boxes. The CO2 will additionally radiate at specific wavelengths but the large proportion of escaping radiation will be from the warm insulation/salt. the CO2 will additionally intercept some of the wavelengths from the walls of the box/window preventing this escaping The hot Co2 will radiate in all directions. this wold reduce the radiation escaping at the absorption frequencies.

    I think i would suggest that the CO2 gas will cool slower.
    ———
    Experiment 2. (high cost) Attach two gas cylinders with regulators one CO2, one N2, to two 10m long lengths of 5mm PVC tubing. Coil most of the tubing through an insulated container full of hot water. Attach the two open ends of the PVC tubes to two retort stands in front of a cool wall. Set gas flow from both tubes to 1 L/s. Observe the gas flowing out of both tubes with a high quality IR camera capable of seeing beyond 15um. Are the results – A. Both tubes are visible as warm, but both gas plumes are undetectable. B. Both tubes are visible as warm and the CO2 gas plume is also visible
    —————
    both tubes will be visible at same temperature. N2 will be invisible. CO2 will show up as warm plume but on a camera adjusted for BB radiation the temp will be much less than the actual temp..
    ————-
    Or perhaps this – “What would happen to convective circulation in the lower atmosphere if the atmosphere contained no radiative gases?”

    Convection does not depend on ghgs. The ground would radiate as a BB and the lw radiation would all escape without absorption with no ghgs. The ground/sea transfers heat (conducts) from/to the non ghg atmosphere and eventually equilibrium will be reached when radiation from the ground = radiation from the sun. the ground temp will be the same as the lowest layer of atmos temp and presumably the amos will cool at adiabatic lapse rate from this temp

    *****************
    additional

    http://www.nrel.gov/midc/srrl_bms/

    has un-modified upward/downwar IR measurements
    These are used here:
    http://www.climateandstuff.blogspot.co.uk/2012/09/some-more-analysis-of-ud-lwir-and-clouds.html
    and
    http://www.climateandstuff.blogspot.co.uk/search/label/back%20radiation
    but you to can download the data

    Then there are these which show DLWIR=ULWIR on some days wierd??
    http://www.patarnott.com/atms749/pdf/LongWaveIrradianceMeas.pdf
    Downward longwave irradiance uncertainty under arctic atmospheres: Measurements and modeling
    http://www.slf.ch/ueber/mitarbeiter/homepages/marty/publications/Marty2003_IPASRCII_JGR.pdf
    Figure 2
    Enjoy

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