Discussions on pyrgeometers (IR measurement)

Posted: February 11, 2013 by tchannon in Measurement, Surfacestation

ImageThe subject of pyrgeometers as used in meterology and climatology turns up from time to time on the Talkshop. Let’s have that as a discussion in it’s own thread.

I’m writing here as an electronics instrumentation engineer although I am not familar with these instruments. In a different life you would be surprised.

Web page for a low cost (all relative) model is to the right where I have used this web snap because the lower illustration shows two instruments mounted back to back forming a “net” instrument (only the upper has a skyshade)

The same company do a top of range model for science work type CGR-4 (linked here) which is referenced by BADC (British Atmospheric Data Centre), part of NERC (Natural Environment Research Council) which is the major academic organisation in the UK.

Their page on this instrument is here and includes an important piece of information the spectral response.Image

This is one part of the whole instrument problem, nothing is perfect. I expect this characteristic is the result of a combination of factors

  • actual plastic/glass perhaps with fillers
  • spluttered “optical” filter at IR comprising many micron layers of materials forming a filter not dissimilarly to delay in electronics

I suspect the polar response against filter characteristic is imperfect too.

There are many manufacturers and models where the foregoing is as example and should not be taken as promotional.

Most of these instruments use some kind of solid state electricity generator variously named, all more or less a variation on one theme

  • Seebeck effect
  • thermocouple
  • thermopile (several thermocouples connected together)
  • Peltier diode

These do not do magic: one end is hot, the other cold, generates electricity roughly in proportion to the temperature difference. Other technologies suggest themselves, some fancy. What we have here strikes me as crude and cheap, actual reality with many things.

So far as I have seen the pyrgeometers are sensors only which can drive any suitable indicator

  • galvanometer / moving coil
  • paper recorder
  • digitisation

The indicator adds additional errors.

Most or all of these devices cannot handle direct sunlight without error and where this is important an active shield is used. This needs discussing, what exactly is the problem?

Matching with other wavelength sensors is I suspect not very good.

So far as I know these are dumb sensors which have no idea what exactly they are sensing and certainly cannot distinguish between water and CO2 or a variety of other things.

For outbound usage there is a major problem if that is intended to measure outbound from the ground: generalising from the exact location of the instrument to even a short distance away is usually unsafe. Put another way there is no safe way to measure what the ground is emitting. Similarly there is no way to know what or where inbound originated. Atmospheric profile data (radiosonde/sounder) would help. The whole thing is vague.

Put at it’s crudest, these are cloud detectors.

Accuracy? In the field I’d put this at with care better than 5% and worst case much much worse, after which scratching starts. Feel free to argue, ends in metrology. (correct spelling)

An example of a cloud detector appeared in this article http://tallbloke.wordpress.com/2012/04/14/yes-virginia-back-radiation-delivers-measurable-heat-just-not-very-much/

[update, adding links]

This article

http://tallbloke.wordpress.com/2012/03/16/hans-jelbring-back-radiation-and-observational-meteorologial-evidence/

and particularly this comment with plot and tabular data

http://tallbloke.wordpress.com/2012/03/16/hans-jelbring-back-radiation-and-observational-meteorologial-evidence/comment-page-1/#comment-20475

[/update]

Post by Tim Channon

Comments
  1. tchannon says:

    Comment by article author and moderator. I am by hand moving several comments off a different article to below here. No offence is meant.

    Copied there started here http://tallbloke.wordpress.com/2013/02/04/david-cosserat-atmospheric-thermal-enhancement-part-i-the-great-debate-begins/comment-page-1/#comment-43389

  2. I’ve been looking at data from:
    http://www.nrel.gov/midc/srrl_bms/
    loads of Raw data recorded every minute (I’ve used the hour data)

    The results of analysis
    http://climateandstuff.blogspot.co.uk/2013/02/what-affects-dlwir.html
    and
    http://climateandstuff.blogspot.co.uk/2013/01/yearly-co2-variation-shown-as-change-in.html

    These look at the effects of various parameters on DLWIR as measured on the PIR devices in the measurement array. The most unexpected is the effect of hour of day. DLWIR is greater in morning and evening – don’t see why though.

  3. J Martin says:

    TheFordPrefect, “DLWIR is greater in morning and evening – don’t see why though.”

    I don’t understand DLWIR at all and find conversations about it just confusing. But one thing I did want to try to better understand is the Pointing (? did I get that right ?) effect, perhaps that has some relevance to the am. pm. phenomenon.

    I can’t find anything on Google about it, but I may well be searching for the wrong thing or wrong spelling.

  4. Kristian says:

    TheFordPrefect, you say: “… DLWIR as measured on the PIR devices …”

    That’s the whole point. DLWIR is NOT ‘measured’ by the PIR devices. It is computed.

  5. Bryan says:

    J Martin says:

    “I don’t understand DLWIR at all and find conversations about it just confusing.”

    This is because DLWIR cannot be measured directly.
    Instruments that claim to measure DLWIR are measuring an INFERRED value.
    The pyrgeometer is a typical device

    What can be measured directly is the net radiative flux (H) or heat flow because it is a real physical property.

    Take the simple case of atmospheric science at night it.

    The Earth surface radiates up (ULWIR) with a value of the local temperature fed into the SB equation(U).
    The Atmosphere radiates down (DLWIR) with a value of the multiple temperatures fed into the SB equation(D).

    This part is pure guess work and inaccurate because of the multiple temperatures of a filtered source for which the SB equation is invalid.

    (Its interesting that SoD now admits this and a line by line value of the IR gases needs to be taken for an accurate result )

    The instrument is calibrated to read D = H – U

    This gives the 333W/m2 value in the KT diagrams .

    The pyrgeometer is probably the most inaccurate instrument of modern times and itsproblems have been highlighted several times.

    The POYNTING VECTOR comes from the clasical theories of Maxwell .
    It gives the direction of heat flow as a single value.
    Maxwells Theories are well established .

    They are accurate for radation wavelengths > 3 um
    This includes approximately all nighttime radiation.

    They are inaccurate for radiation < 3um
    This is a problem if using them if solaar radiation is involved.

  6. Bryan says: February 10, 2013 at 12:38 pm

    …This is because DLWIR cannot be measured directly.
    Instruments that claim to measure DLWIR are measuring an INFERRED value.
    The pyrgeometer is a typical device

    From the nrel site linked in my post

    PRECISION INFRARED RADIOMETER
    Model PIR
    The Precision Infrared Radiometer, Pyrgeometer, is intended for unidirectional operation in the measurement, separately, of incoming or outgoing terrestrial radiation as distinct from net long-wave flux. The PIR comprises a circular multi-junction wire-wound Eppley thermopile which has the ability to withstand severe mechanical vibration and shock. Its receiver is coated with Parson’s black lacquer (non-wavelength selective absorption). Temperature compensation of detector response is incorporated. Radiation emitted by the detector in its corresponding orientation is automatically compensated, eliminating that portion of the signal. A battery voltage, precisely controlled by a thermistor which senses detector temperature continuously, is introduced into the principle electrical circuit.

    Isolation of long-wave radiation from solar short-wave radiation in daytime is accomplished by using a silicone dome. The inner surface of this hemisphere has a vacuum-deposited interference filter with a transmission range of approximately 3.5 to 50 µm.

    SPECIFICATIONS

    Sensitivity: approx. 4 µV/Wm-2.
    Impedance: approx. 700 Ohms.
    Temperature Dependence: ±1% over ambient temperature range -20 to +40°C.
    Linearity: ±1% from 0 to 700 Wm-2.
    Response time: 2 seconds (1/e signal).
    Cosine: better than 5%.
    Mechanical Vibration: tested up to 20 g’s without damage.
    Calibration: blackbody reference.
    Size: 5.75 inch diameter, 3.5 inches high.
    Weight: 7 pounds.
    Orientation: Performance is not affected by orientation or tilt.
    ————————-

    This looks to me as if it is measuring the heating effect (thermopile) of radiation hitting the dome of the sensor (transmission 3.5 to 50um. The thermopile of course generates a voltage dependant on the temperature difference between one side and the other The non-dome side is not exposed to external radiation so no effect there. However, the nondome side temperature must be measured and compensated.
    The instrument also compensates for its own generated IR.
    No assumption of BB radiation is assumed. It is the ACTUAL heating effect of IR radiation of narrow or wide bandwith hitting the sensor that is the cause.

    This all sounds as accurate as a liquid in glasss thermometer to me.

    If the radiative “temperature” is less than the receiver temperature then the thermopile still measures – see my series of posts about thermal imaging – the camera microbolometers sitting at 20+C shows temperatures down to -40C

  7. Bryan says:

    thefordprefect

    The pyrgometer has as a detector a wire-wound Eppley thermopile

    This measures heat flow as I said above.
    So far so good.

    What is INFERRED from this reading is not so good.

    Most people don’t realise that when pointed to the cold sky more radiation leaves the pyrgeometer than enters it from the sky.
    If you read this link it makes clear that the SB equation is used extensively for its calibration.
    Even in this late link (2006) the paper admits the instrument is showing an uncertainty of -5 to – 17W/m2
    So for a real reading of 100W/m2 the instrument would return anything between 95 to 83W/m2

    http://www.arm.gov/publications/proceedings/conf16/extended_abs/stoffel_t.pdf

  8. tchannon says:

    Under ideal conditions.

    In addition that text demonstrates a woeful lack of information, takes many things assumed.

    Still comes down to you don’t know what is being measured.

    In addition it is even more difficult, I suggest impossible to measure outgoing.

  9. Kristian says:

    Bryan, I’m with you on this one. Here’s what Wikipedia has to say about the way pyrgeometers ‘measure’ DLWIR:

    “The atmosphere and the pyrgeometer (in effect its sensor surface) exchange long wave IR radiation. This results in a net radiation balance according to:

    Enet = Ein – Eout

    Where:
    Enet – net radiation at sensor surface [W/m^2]
    Ein – Long-wave radiation received from the atmosphere [W/m^2]
    Eout – Long-wave radiation emitted by the sensor surface [W/m^2]

    The pyrgeometer’s thermopile DETECTS THE NET RADIATION balance between the incoming and outgoing long wave radiation flux and CONVERTS IT TO A VOLTAGE according to the equation below.

    Enet = Uemf/S

    Where:
    Enet – net radiation at sensor surface [W/m^2]
    Uemf – termopile output voltage [V]
    S – sensitivity/calibration factor of instrument [V/W/m^2]

    The value for S is determined during calibration of the instrument. The calibration is performed at the production factory with a reference instrument traceable to a regional calibration center.

    To DERIVE THE ABSOLUTE DOWNWARD LONG WAVE FLUX, the temperature of the pyrgeometer has to be taken into account. It is measured using a temperature sensor inside the instrument, near the cold junctions of the thermopile. The pyrgeometer is considered to approximate a black body. Due to this it emits long wave radiation according to:

    Eout = σ * T^4

    Where:
    Eout – Long-wave radiation emitted by the earth surface [W/m^2]
    σ – Stefan-Boltzmann constant [W/(m^2 K^4)]
    T – Absolute temperature of pyrgeometer detector [kelvins]

    From the calculations above the incoming long wave radiation can be derived. This is usually done by rearranging the equations above to yield the so called pyrgeometer equation by Albrecht and Cox.

    Ein = Uemf/S + σ * T^4

    Where all the variables have the same meaning as before.

    As a result, THE DETECTED VOLTAGE AND INSTRUMENT TEMPERATURE YIELD THE TOTAL global [?] LONG WAVE DOWNWARD RADIATION.”

    http://en.wikipedia.org/wiki/Pyrgeometer

  10. Bryan says: February 10, 2013 at 3:37 pm and
    Kristian says February 10, 2013 at 6:04 pm

    Thanks for the calibration doc ref.
    Yes I agree that the PIRs are calibrated using a black body – ie. the calibrating surface is radiating at frequencies conforming to Pank’s law for a solid body.
    I agree that the thermopile is cooling as a black body
    I agree that radiation from the sky is mainly in the form of discrete wavelengths corresponding to GHG absoption bands.
    BUT
    The electrical output (measured signal) corresponds to the temperature difference between the front and back faces of the thermopile. This temperature difference is caused by the incoming radiation being absorbed and the energy converted to heat. It does not depend on the incoming radiation being bb or discrete the total energy of the radiation will be converted,
    The temperature reached by the thermopile will be determined by the balance between energy received as discrete wavelengts and energy lost as black body.
    If anything the individual discrete wavelengths will cause less heating than the equivalent BB. But this is correct – we want to know the w/sqm energy from the sky (this is wgat the sensor is measuring). We do not want the peak radiation from the sky. We want the heating effect.

  11. Bryan says:

    thefordprefect

    There is a difference between a bolometer sensor and a pyrgeometer sensor.

    A bolometer uses a detector whose resistance changes when heated.
    For accurate work a semiconductor is used.
    This resistance is one part of a balanced Wheatstone bridge.
    When it goes out of balance a current flows.
    I think a bolometer is an accurate instrument.

    A thermopile is used in a pyrgeometer.
    It is a series of thermocouples.
    A voltage is developed if there is a temperature difference between the thermocouple terminals.
    It measures heat flow.
    This is then used to predict radiation flows according to several ‘iffy’ conditions used in its calibration.
    There is circular logic in its operation.
    if it is calibrated with faulty theory then it can only confirm the faulty theory.

  12. Kristian says:

    thefordprefect, you say: “The electrical output (measured signal) corresponds to the temperature difference between the front and back faces of the thermopile. This temperature difference is caused by the incoming radiation being absorbed and the energy converted to heat.”

    I’m afraid not. Not from the sky. You should take note of what Bryan said earlier: ‘Most people don’t realise that when pointed to the cold sky more radiation leaves the pyrgeometer than enters it from the sky.’ This means there can be no heating of the thermopile in such case. The front face of the thermopile will cool, not warm, because the net flux is negative. This will produce a negative voltage according to the equation given above (Enet = Uemf/S) to be used in deriving the DLWIR (Ein) value from the equation Ein = Uemf/S + σ * T^4, where the last element is IR emitted by the sensor (Eout) calculated from its absolute temperature.

    The base assumption here is the first equation above: Enet = Ein – Eout. This concept is what the whole issue is about. It is a simplified way to picture what happens. To illustrate the energy exchange. The two component fluxes are however not ‘real’ in any physical, measurable sense. That only goes for the net flux. The actual transfer of heat. The concept works, though. I have no trouble accepting the notion of a two-way flow. The problem has to do with the way the confusion it may cause is capitalized on by people making lofty claims based on energy diagrams such as Trenberth & Kiehl’s … It might confuse one into thinking that the atmosphere is bringing heat to Earth’s global surface. That the atmosphere is somehow a second heat source. And that the DLWIR flux can and should be equated to and bunched together with the net solar flux as a heat giver.

  13. heres a video I did of boiling water with a thermal imaging camera (2um to 13um sensitivity)

    The steam is invisible but put a piece of paper into it and it starts radiating as a bb at 100C!

    there is more here:
    http://climateandstuff.blogspot.co.uk/2012/12/water-vapour-and-thermal-imaging.html

  14. Kristian says: February 10, 2013 at 10:46 pm

    thefordprefect, you say: “The electrical output (measured signal) corresponds to the temperature difference between the front and back faces of the thermopile. This temperature difference is caused by the incoming radiation being absorbed and the energy converted to heat.”

    I’m afraid not. Not from the sky. You should take note of what Bryan said earlier: ‘Most people don’t realise that when pointed to the cold sky more radiation leaves the pyrgeometer than enters it from the sky.’

    Apologies – bad terminology.

    point a microbolometer array through a germanium lens (i.e. a thermal imaging camera) that focuses objects at -273 to +1500C onto parts of the array.

    at -273C the bolometer sees no source of heat so it will be at say 20C this being the temperature of the bolometer when it is warmed by camera ambient within and losing heat at 20C
    at -20C the bolometer sees both focused IR from the object and the energy from the 20C local camera ambient. The temperature 20C is the same as before (within reason) so the rate of loss of heat will be the same as when -273C is focused. When the bolometer radiates it does not know the temperature of its destination. The bolometer is now receiving more energy than when -273C is focused. The bolometer therefore heats a fraction to say 20.1C

    Hopefully you can see where this is going.
    The microbolometer temperature is modified by temperatures above -273C – the IR is focussed by the germanium lens onto each part of the array. The temperature of the bolometer is then converted to a video signal. This can therefore show a difference between the bolometer with focussed ir from an object at -20c and the bolometer at -273C DESPITE the fact the array is at 20C.

    The lense does not focus cold rays!

    The stuff on my blog shows photos/videos taken with a room temperature microbolometer array. This includes sky photos showing temperatures down to -40C (the camera limit) together in the same frame as a temperature of -1. All measured to an accuracy of +-2C with a sensitivity of 0.03C
    (note that as ambient changes the array is calibrated by viewing a isothermal plate rather than the image required)

    If cold objects did not add energy to a warm object then this sort of camera would not work. (note that it does not cause warming it slows cooling.) There are no cool rays to focus onto the array so it has to be IR.

    The difference between bolometers and thermopiles is large. bolometers are used for arrays as these can be processed like silicon semiconductors. But in essence the physics is similar.a sensor temperature is modified by the IR falling on it (from any thing above -273C) and this is referenced to a measured internal temperature.

    I agree that the accuracy of the PIR is not good about 5w/sqm at 300W/sqm i.e. about 2% but saying this negates any measurements seems over the top..

  15. Good move – stops this cluttering the other thread!
    some more stuff to consider:

    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

    Clalibration stuff
    http://www.nrel.gov/aim/borcal.html

    Pictures of measurement site
    http://www.nrel.gov/solar_radiation/solar_photos.html

    You say:
    Matching with other wavelength sensors is I suspect not very good.

    true – these know nothing of the wavelength just that it passes their input filters

    So far as I know these are dumb sensors which have no idea what exactly they are sensing and certainly cannot distinguish between water and CO2 or a variety of other things.

    true – they absorb all filtered radiation and heat up. CO2 H2O are just sources of radiation.

    For outbound usage there is a major problem if that is intended to measure outbound from the ground: generalising from the exact location of the instrument to even a short distance away is usually unsafe. Put another way there is no safe way to measure what the ground is emitting. Similarly there is no way to know what or where inbound originated. Atmospheric profile data (radiosonde/sounder) would help. The whole thing is vague.

    I think it a bit strange that you assume the people involved with these measurements have not considered such problems – it is what they have trained for!

    Put at it’s crudest, these are cloud detectors.

    No pyroheliometers would detect clouds as they measure direct sunlight.
    pyronometers are shaded from direct sunlight and measure LW IR
    Only the 1st would indicate clouds

    Accuracy? In the field I’d put this at with care better than 5% and worst case much much worse, after which scratching starts. Feel free to argue, ends in metrology. (correct spelling)

    looking at some of documents some sensors are better than 1% and not many are as high as 5% inaccurate

    There’s more here (but ignore my wafflings on lapse rates)
    http://climateandstuff.blogspot.co.uk/2012/01/are-adiabatic-lapse-rates-controlling.html

  16. Tim C,

    Congratulations. Moving the issue of the accuracy of pyrgeometers from “Atmospheric Thermal Enhancement Part I – The Great Debate Begins” to this new thread here is a stroke of genius. This is indeed a technical issue that needs resolving one way or the other because it keeps popping up when discussing the reality or otherwise of downwelling radiation from atmosphere to surface.

    I await the emergence of some sign of expertise concerning this practical engineering issue rather than just the extensive arm waving and wild assertions that we have been subjected to hitherto. It will also excellently unclog the other thread so we can get on with our other main business there.

  17. tchannon says:

    I hope it works David rather than wreck the blog. What we hope will work rarely comes to pass.

    Doing a move on the managed version of WordPress is ghastly because there is no direct database access, can only copy field by field, not merely move pointers or one hit copy. I’ve probably missing some. I had to do a fast but sane article to go with this.

  18. Bryan says:

    thefordprefect

    Did you notice that the confidence in the accuracy of pyrgeometers in your 2003 link turned out to be misplaced by my 2006 link?
    This pattern has been repeated many times since pyrgeometers first appeared around 1950

  19. AlecM says:

    The pyrgeometer is a pyrometer for which the temperature signal is converted by the S-B equation to give the potential energy flux that the emitter(s) in the field of view would emit to a sink at absolute zero.

    This not a real energy flux. You prove this very simply. Have two pyrgeometers back to back in zero temperature gradient and the net signal is zero. Take one away and the signal jumps to the temperature value.

    Then manufacturers are very specific on this – to measure real energy flux you need the back to back signal.So the signal is an artefact of the shield behind the detector.

    This has been a 50 year mistake by people who don’t know the most basic physics. The Trenberth Energy Budget has in it 100s of man years of wasted effort. Correct the many other mistakes in the physics and there are three separate reasons why there can never be any CO2-AGW.

    This has been a disaster for science.

  20. tchannon says:

    My comment about glorified cloud detector is pointedly cynical yet that is reality, it is water which is dominating. Clear sky day or night is black, bone dry moreso.

    I view the sky situation as about attenuation, no point in considering the inner details. This works both directions so perhaps this is similar to the Throttle concept.

    A lot of people do domain jumping, ie. invoke Stephan-Boltzman to switch temperature with flux. I see this as very dubious since it can only be done if all the parameters are known, which they never are. From this point of view a fluxmeter seems a good thing.

    On the other hand the fluxmeters I know about are proxy devices, the case with almost all measurements of real things anyway.

    ==
    “I think it a bit strange that you assume the people involved with these measurements have not considered such problems – it is what they have trained for!”

    Experience. Example: why is it a universal defect in eg, climatology is violating nyquist and shannon given these people are trained? Or, why does the Hurst issue exist? Or, why do fatal flaws exist in computer language design?

    A lot of this comes down to messes which in turn comes down to politics. Often many actually know things are wrong but muddle on anyway, no easy way for the buck to stop. Does happen sometimes, disruptive.

    In this context I and I assume all of you are aware of your own specialisms where you know certain things are wonky but do you publish this or is it part of “the knowledge”. Outsiders won’t know.
    Baldly accepting because someone says so etc. doesn’t break conventions, lead to insight. Often a waste of time, sure.

    Obviously a zontal plate(*) is a far better way to actually measure flux.

    See the problem? Not how it is done, just like switching all drinks to water, the people won’t buy this. If someone has a better mousetrap they charge more and so on.

    * fictitious
    ==
    So what is one of these sensors?

    It looks to me like a thermal short circuit where thermal flux does Stephan-Boltzman on the front side, get out a function of the power dissipated. Loss in the filter comes out as in band heat.

    The “trick” of using heat equivalent is possibly the oldest and most common metrology technique where extreme frequency bandwidth is wanted. Basis is everything ends up as heat.


    Credit: Wiebe Nijland
    http://www.ir-photo.net/topics.html

    Near IR but good enough.
    Sky is black apart from clouds, vegetation is white. This incidentally is why Stephenson screen exposure is so critical, horizon, a collar of hot rising with vegetation height.

  21. Kristian says, February 11, 2013 at 2:30 am: The concept works, though. I have no trouble accepting the notion of a two-way flow. The problem has to do with the way the confusion it may cause is capitalized on by people making lofty claims based on energy diagrams such as Trenberth & Kiehl’s … It might confuse one into thinking that the atmosphere is bringing heat to Earth’s global surface. That the atmosphere is somehow a second heat source. And that the DLWIR flux can and should be equated to and bunched together with the net solar flux as a heat giver.

    So there we have it. A changed Kristian from the one I encountered at my blog article. You are now (apparently) saying that, yes, pyrgeometers do work reasonably well after all (having rubbished them earlier) and that you personally have no problem with the idea of two-way energy flow (by which I take it you mean Trenberth’s upwelling and downwelling radiation figures of 356Wm-2 and 333Wm-2 respectively).

    If this is really what you do mean then you have wasted everybody’s time on a wild goose chase.

    You are entitled to your opinion that people with ulterior motives may capitalise on the two-way flow to imply radiation is the cause (rather than the symptom) of the phenomenon. But the whole point of my article was to show that the two-way enhanced radiation flow is a consequencenot a cause of the enhanced KE (read elevated temperature) of the atmosphere and that skeptics shouldn’t shy away from it but should take it on board to move the debate forward armed with the knowledge that they can do so from a position of strength, not weakness.

  22. Tim,

    By an exquisite coincidence I have found a doctoral thesis here that reports actual observations of downwelling radiation using a Kipp & Zonen professional pyrgeometer:
    http://www.tdx.cat/bitstream/handle/10803/31841/tavm.pdf;jsessionid=942324F10A34C255B358DCD71581E2CE.tdx2?sequence=3

    On page 91, Fig.4.6 shows that actual pyrgeometer readings are in the ~300Wm-2 arena, exactly as Trenberth has them.

    What a nonsensical diversion this has been.

    Interesting though in its own right – this is real science in action :-)

  23. mkelly says:

    David Socrates says:

    February 11, 2013 at 8:03 pm

    I skimmed over the paper you linked to and in all references he mentioned I did not see one for Hottel and his work with CO2 in heat transfer. The emissivity of CO2 is a question that many of us say is so low as not possible to do what is asked of it. Also with the Trenberth diagram in the paper I am not sure the writer could have come up with anything else other than support for Trenberth.

  24. tchannon says:

    Excellent find.

  25. Tim Folkerts says:

    Kristian says ” It might confuse one into thinking that the atmosphere is bringing heat to Earth’s global surface. That the atmosphere is somehow a second heat source.”

    You can hardly blame a scientist for the potential confusion of a non-scientist reading a scientific paper. :-)

  26. mkelly says, February 11, 2013 at 8:39 pm: Also with the Trenberth diagram in the paper I am not sure the writer could have come up with anything else other than support for Trenberth.

    So, in effect, are you suggesting the author fiddled his own doctoral thesis experimental results?

    As I ask everyone who challenges Trenberth’s figures: do you have some alternative values, with references, that you feel confident to put forward?

  27. mkelly says:

    David Socrates says:

    February 11, 2013 at 9:20 pm

    No I don’t think he fiddled with anything. He may have just confirmed what he thought from the begining. And if these instruments work the way folks here say they do he had to get the same answer since he was measuring the same thing with the same kind of device.

    And you missed my main point, the lack of citation for Hottel and his work with CO2.

  28. tchannon says:

    Updated article with links to Hans Jelbring’s from Sweden and comment with data from Koorin expedition.

  29. tjfolkerts says:

    Bryan says: “What can be measured directly is the net radiative flux (H) or heat flow because it is a real physical property.

    Several people have said things to this effect, and the more I think about it the less I agree.

    * It is often EASY to measure net fluxes (of various sorts)
    * It is often PRACTICAL to measure net fluxes.

    But “net flux” is NOT the “real physical property”.

    Consider a slight breeze — blowing maybe 1 m/s. That would be a net flux of about 1 kg/m^2/s or about 50 moles/m^2/s or 3E25 particles/m^2/s blowing along. But what is “really” happening is that the molecules in the air are moving randomly with speeds on the order of several 100 m/s. Nearly 1/2 of the molecules are heading “upstream” at several 100 m/s. There is a large flux of molecules heading upstream, and a slightly larger flux heading downstream.

    The effect is even stronger in electric circuits. The “drift velocity” of the conduction electrons is typically a few cm/s, while the thermal speeds of the electrons are around 10^6 m/s.

    For IR in the atmosphere, what is “really” happening is that lots of photons are heading down through each square meter each second, and “lots + a few percent” of photons are heading up.

    It might be EASIER to measure the net flux of photons. It might be MORE PRACTICAL in some circumstances to measure the net flux. But what is “really” happening is a flux downward and another flux upward.

    [Reply] Not forgetting the flux sideways, which is four times bigger than the up or down flux. – TB.

  30. tchannon says:

    Oh boy, have I a post coming up if I can put it all together, maybe.

    Earlier I popped outside, pointed an IR thermometer at the sky -7C, air temperature ~1C, no ice, heavy overcast. Time, about 22:00hrs

    The twist, I happen to live 30km from one the world’s foremost atmospheric observatories which has advanced radar and lidar. It was all working yesterday so I have grabbed the plots, 13 of them. Can even see the radar profile of the cold front coming through with light snow and temperature change, this brought snow to London area.

    Two of the plot are for… pyrgeometer, grin.

    One was about 310 W/sqm when I took the readings, SB gives -1.23C, the other trace I think I now understand as is net, looks like tracking zero, ie. no heat flow.

    If you are fast you can see “yesterday”, back up to the other sensor plots.
    http://www.stfc.ac.uk/Chilbolton/weather/Visible+and+IR+radiation+sensors/26698.aspx

  31. tjfolkerts says:

    Tim C,

    The top plot is a “pyranometer”:

    ” A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface and is a sensor that is designed to measure the solar radiation flux density (in watts per metre square) from a field of view of 180 degrees.”

    http://en.wikipedia.org/wiki/Pyranometer

    So it is pretty obvious that this is a cloudy day. The solar flux stays below ~ 200 W/m^2 even at noon (and of course tracks right near 0 W/m^2 all night long). The IR flux (from the clouds and the GHGs below the clouds) is steady and strong. In fact, the one moment when the sunlight is strongest (around 13:00), the IR dips a tiny bit — I bet the clouds broke briefly at that time.

  32. tjfolkerts says:

    Ballpark figures. Chilbolton is ~ 51 N. Direct overhead sunlight is about 1000 W/m^2 (after accounting for atmospheric absorption).

    So on the first day of winter (Dec 21), the noon insolation should be about
    1000 cos (51+23) = 275 W/m^2

    On the first day of spring (Mar 21), the noon insolation should be about
    1000 cos (51) = 625 W/m^2.

    So if you get a sunny day soon, I expect the top plot to go to ~ 500 W/m^2 (and the bottom plot to go down to ~ 100 W/m^2)

  33. wayne says:

    tchannon: “… looks like tracking zero, ie. no heat flow …”

    Can’t wait for a good post on that Tim. Needed.

    Same thing NOAA’s ESRL pyrgeometers generally show in different locations when there are dense clouds above, no or very little net surface up l.w.

    ESRL also show’s the upwelling l.w. above the clouds (satellite I assume) and when cloudy (warmer at surface, no net, so cloud bottoms are at the same temp as the surface), the net l.w. to space actually goes UP a bit, more energy lost for the clouds are closer to the ToA or space.

    Kinda like clouds often make the surface stay warmer but the net effect overall is still more cooling with cloud cover. You will feel that upper air cooling sooner or later, usually the very first break in the clouds, then the surface temps plummet. Ever notice that? After a cloudy period, the first clear night is the coldest, with gradual warming each succeeding night as it creeps back to normal.

  34. Tim Cullen says:

    David Socrates says: February 11, 2013 at 9:20 pm
    As I ask everyone who challenges Trenberth’s figures: do you have some alternative values, with references, that you feel confident to put forward?

    This is a VERY non-scientific approach.

    To falsify a theory the “challenger” is NOT required to supply a “alternative” theory… equally a “challenger” is NOT required to supply “alternative values”.

    Demanding “alternative values” does not make “Trenberth’s figures” correct – end of story.

    In the case of the “energy budget” it is demonstrably clear that there is insufficient knowledge [and data] regarding the atmospheric processes, flows and transformations therefore nobody is in a position to generate an “energy budget” because there is insufficient knowledge and data.

    “Insufficient Data” is a perfectly legitimate scientific position which should [hopefully] encourage the scientific community to do more research [not more posturing].

  35. AlecM says:

    mkelly: 8.39 pm.

    A radiometer in the atmosphere measures a different emissivity to the work of Hottel. Leckner showed an error in the measurement path of Hottel, whom I once met. The reason is very simple.and has been totally missed by Climate Alchemy.

    The experimental apparatus of Hottel and Leckner was a heated tube so what you measure is the result of the mutual interaction of the gas and the wall at which indirect thermalisation takes place. The measurement in an air path includes the GHG effects in that path.

    A satellite radiometer will therefore measure about half the apparent emissivity of CO2 for a given temperature.It depends on the GHG being in self-absorption mode, standard in analytical spectroscopy but totally unrecognised by Climate Alchemy. Pyrgeometers do not and cannot measure an energy flux. And if you look at the real way they work, it isn’t even radiative equilibrium – they rely on internal convection.

    This is because the atmospheric window means you need to put as much radiant energy to the sensor plate outside the AW as you lose in the AW. Yes folks, radiative equilibrium with a non grey body, semi-transparent emitter means bidirectional energy flux so for air at 15 °C, the pyrgeometer sensor has to be at -13.5 °C, hence it’s internal convection that causes thermal equilibrium.

    If these Climate Alchemists had used bolometers,they might have made a science out it it. As it is they are hoist on their own petards, unable to go back to accepting there can never be any CO2-AGW.

    I am writing a paper about this but it will never be published by the CO2-religion fanboys. However, it shows the 13 errors in basic physics some very famous people like Sagan have made as they created the monster called climate science, the biggest religious fraud since Phlogiston.

    As for my tip for the top of the deluded – it’s Houghton who made three serious mistakes and misled the rest. These people have forgotten how to do basic experimentation.

  36. thefordprefect says:

    tchannon says: February 12, 2013 at 3:12 am

    The top plot is a visible light only plot for solar w/sqm it purposedly shows very little LWIR
    The bottom plot contains no w/sqm from Visible so most solar output is ignored (if it is not sheilded from the sun then it will also measure the LWIR from the solar spectrum.

    We are requiring the “heating” (less cooling than no radiation) effect of the radiation and this is just what the systems do.
    The sensor is warmed (by a specific heater or body temperature or thermal output of electronics – it does not matter)
    The sensor is a solid object with the to surface coated to maximise emissivity
    The sensor top surface both radiates as a black body (as nearly as possible) and absorbs energy as a black body.
    The rate of loss from the top surface is determined by its temperature (a value set by the flux difference between internal and through the window external.
    The rate of increase is determined not by external temperature (although this has an efffect) but by the radiation received through the window. (Put this in the thermosphere and it will measure very little IR flux despite the very high temperature).
    The incoming radiation is not black body it is discrete bands of IR These bands will have less heating effect than a BB equivalent but that is what we want. we want the sensor to respond to the heating effect of the radiation not its temperature.

    so we have the sensor cold junction (which will be warm!) sitting at a measured temperature and not responding to incoming IR and the hot junction sitting at a temperature dependant on the BB loss (at a measured temperature) +- the incoming IR.
    It is now possible to calulate the heating effect of the IR.

    Pointing an IR thermometer at the sky proves very little unfortunately see my thermal imaging pages http://www.climateandstuff.blogspot.co.uk/2012/12/water-vapour-and-thermal-imaging.html.
    Vapour from boiling water shows up as 28C until it heats a solid surface (the vapour is radiating with wavelengths outside the cameras bandwidth 2 to 13um the paper is radiating as a BB at 90C.
    A IR thermometer would have similar wavelength filtering. Both camera and thermometer expect the heat source to be a BB. Vapour/GHGs/clouds are not BBs!
    When I used the camera to measure sky temperature it was less than -40C for clear sky.

    The important stuff here is:

    Cold objects radiate and if this radiation hits a hot object surrounded by even colder objects (space) then the hot object cools more slowly and reaches a warmer stable temperature.

    Measurement of ULWIR and DLWIR you need the “heating” effect of the IR not its temperature – net flux will determine the temperature.

    GHG and water vapour do not radiate as a BB

    IR Thermometers/cameras expect the radiation to be from a BB

  37. Tim Folkerts says:

    “[Reply] Not forgetting the flux sideways, which is four times bigger than the up or down flux. – TB.

    Not really — the flux in any direction is pretty much the same.

    ~ 396 W/m^2 = upward flux
    ~ 333 W/m^2 = downward flux
    ~ 365 W/m^2 = northward flux
    ~ 365 W/m^2 = southward flux
    ~ 365 W/m^2 = eastward flux
    ~ 365 W/m^2 = westward flux

    (We could even throw in things like
    ~ 360 W/m^2 = flux heading NNE, 10 degrees below horizontal
    ~ 380 W/m^2 = flux heading ESE, 40 degrees above horizontal)

    The FOUR fluxes sideways are each about the same as the fluxes in any other direction. Of course, since the north & south flux oppose each other, the net flux north or east or southwest is basically zero. So for energy balance (the “practical” aspect I was talking about), the sideways fluxes can pretty well be ignored.

  38. mkelly says:

    AlecM says:

    February 12, 2013 at 9:25 am

    mkelly: 8.39 pm.

    Thank you. I appreciate you taking the time to write that explanation. I hope you publish your 13 errors here on this blog in the future so they can be discussed.

  39. Tim Folkerts says:

    Tim Cullen says: ““Insufficient Data” is a perfectly legitimate scientific position which should [hopefully] encourage the scientific community to do more research [not more posturing].

    True.

    But it is NOT a legitimate scientific position to say “I can’t find any specific problems with your data, and I can’t find any specific problems with your theory, but I don’t like the conclusions it leads to, so I will reject your theory and data on ideological grounds.” The point is that we are NOT facing insufficient data. There is plenty of data that says clouds and GHG’s radiate ~ 333 W/m^2 (give or take several percent, but not give or take 100%) of thermal IR to the ground. There is a robust theory of heat transfer & thermal IR & vibrational modes of polyatomic molecules & atmospheric lapse rates that all support the measurements.

    Research is always good (well, until it becomes simply too expensive to justify continuing), and posturing is bad. But I am always amazed at the number of people (not referring specifically to anyone in this thread) who basically say “I don’t understand math or physics or equations, but I am sure all these PhDs are wrong.”

  40. Tim Folkerts says:

    FordPrefect,

    Thanks for hitchhiking to earth and adding your response at February 12, 2013 at 12:50 pm. I like what you wrote.

  41. Tim Cullen says, February 12, 2013 at 9:05 am: This is a VERY non-scientific approach.To falsify a theory the “challenger” is NOT required to supply a “alternative” theory… equally a “challenger” is NOT required to supply “alternative values”. Demanding “alternative values” does not make “Trenberth’s figures” correct – end of story. In the case of the “energy budget” it is demonstrably clear that there is insufficient knowledge [and data] regarding the atmospheric processes, flows and transformations therefore nobody is in a position to generate an “energy budget” because there is insufficient knowledge and data.

    For some of the Trenberth figures maybe. For others obviously not true. Surely you don’t dispute the solar constant measured by satellite instrumentation. That’s the start of the Trenberth energy budget diagram. Internally, the transfers are indeed estimates. But sniping away at the Trenberth figures, as many people have done, without giving any kind of explanation of why the figures are (apparently) grossly wrong doesn’t help the scientific process either.

    This particular thread is concentrating on just one figure, the radiative flux between atmosphere and surface. Yet still the wild arm-waving goes on, leavened with a snide comment about someone who has written a doctoral thesis using an industry-standard pyrgeometer that appears (dammit!) to confirm (broadly) Trenberth’s own figure.

    Maybe you don’t think I know how to do science because, in trying to assess the significance of an arm wave from an anonymous source, I politely ask each time for some kind of contrary evidence. Well why don’t we skeptics take your suggestion to its logical conclusion and pack up CHALLENGING the warmists on the grounds that it is down to them to prove their case, not down to us to disprove it… :-)

  42. wayne says:

    David Socrates

    But sniping away at the Trenberth figures, as many people have done, without giving any kind of explanation of why the figures are (apparently) grossly wrong doesn’t help the scientific process either.

    This particular thread is concentrating on just one figure, the radiative flux between atmosphere and surface. Yet still the wild arm-waving goes on, leavened with a snide comment about someone who has written a doctoral thesis using an industry-standard pyrgeometer that appears (dammit!) to confirm (broadly) Trenberth’s own figure.

    David, I don’t think anyone here is “sniping away” at Trenberth’s IR figures without cause. That paper you just supplied proves what is being said by so many here, I just bet you missed it when reading his thesis.

    Read about how he says that within the pyrgeometer itself, that any wind or wetness on the IR absorbing and emitting surface (the sensor), is largely influenced by such affects, that is the real world. He is correct, you cannot have simultaneous energy leaving from a surface by conduction (wind) or evaporation (wetness), it drastically lowers what would be seen from a calm dry environment.

    So… they place a window to keep the little sensor as if it existed on a dry and calm Earth. They read 300 Wm-2 of radiation and Trenberth reads 396 and 333 Wm-2 IR from a perfect dry and wind-less sensor and then say this is what our world’s surface and atmosphere are like when looking at infrared. See the problem. I’m not saying it was on purpose, just a slip from reality.

    As for myself, my spreadsheet was an honest attempt to extract out of Kevin Trenberth’s data, I think most of the other data is as close as possible as available to him, what must be, according to the facts above, what our world really, really is like in the IR aspects of our atmosphere when you let the wind and rain and water in and let it manifest itself. you get much lower “real” wet and windy readings from the pyrgeometer when you remove the window.

    Of course, that one specific location does not mimic the oceans (wet) and latitudinal winds so it would be also wrong to just use such a single pyrgeometer, or from a limited number. But, he should have known that the 17 (wind) and 80 Wm-2 (wet) figures are what he should have removed from the 396 Wm-2, ε=1, hypothetical readings to get a closer real look at the energy budget.

    Now all of that was not written and expanded on within that one simple statement about wind, rain, and weather, but, many here can see through those words, this has been covered before, you are the new person here, and they also know it is incorrect as it is being used. Pyrgeometers are the best we have but the data they spit out must be used with all of the other factors involved allowed for.

  43. A C Osborn says:

    Tim Folkerts says:
    February 12, 2013 at 2:20 pm

    There is plenty of data that says clouds and GHG’s radiate ~ 333 W/m^2

    So if I have a large balloon with Infra Red receptors all over it’s top surface can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.
    Will it provide energy to drive electric motors?
    Heat the Balloon’s Atmosphere?
    What height would it be best for the balloon to be at to take advantage of this energy?
    Is anybody using it for anything other than measuring with a pyrgeometer?

  44. Bryan says:

    Tim Folkerts says:

    ” There is plenty of data that says clouds and GHG’s radiate ~ 333 W/m^2 (give or take several percent, but not give or take 100%) ”

    There is plenty of evidence that the pyrgeometer is a very inaccurate device.
    There is plenty of evidence that a pyrgeometer cannot measure accurately to a resolution of plus or minus one unit out of 333

    Yet that is what the presented figure implies.

    1/333 = 0.003 or 0.3% relative uncertainty for the 333W/m2 figure

    I don’t think so

    Why does Trenberth put such unsubstantiated 3 figure accuracy numbers out?
    Its to imply accuracy where it doesn’t exist.

    Fraud or carelessness?
    Who knows?

    The atmospheric window 40 to 66 W/m2 or some number in between?
    Cloud cover and cloud density vary continuously with time.
    This will affect most of the other numbers continuously.

    Is there a point to pluck numbers out of thin air and get them all to match in a diagram ?

  45. mkelly says:

    A C Osborn says:

    February 12, 2013 at 7:03 pm

    Some good questions, sir. Also we are all familar with the r^2 rule for radiationand I have not seen if anyone has ever looked at the output of a CO2 molecule using E=hf and applying the r^2 rule to see when that energy becomes so dilute as to be unmeasurable. Just a thought.

  46. Tim Folkerts says:

    A C Osborn asks a few questions…

    “So if I have a large balloon with Infra Red receptors all over it’s top surface can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.
    Yes, but (as with any heat engine) only if there is a “cold reservoir” around to use. Since you want to use the “cool” atmosphere” as “hot reservoir”, then you would need something even cooler for the “cold reservoir”. The obvious choices would be cooler air higher up, or space.

    “Will it provide energy to drive electric motors?
    Yes, in principle. But in practice it would not be very effective. If i HAD to do this, I would probably take a Stirling engine (http://static.ddmcdn.com/gif/stirling-engine-displacer.jpg) and mount a parabolic reflector aimed at the sky as the cool side (a technique that can be used to freeze water on nights when the local air is above freezing – http://solarcooking.org/radiant-fridge.htm).

    I am now tempted to do this simply to prove it can be done! And it would be cool to own a sterling engine. :-)

    “What height would it be best for the balloon to be at to take advantage of this energy?
    The most important factor would be to get above the clouds (or do it on a clear night). That way the downward IR would have more of the 2.7K background radiation and less of the much warmer atmospheric radiation.

  47. Trick says:

    ACO 7:03 pm – “..can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.”

    No; though you could do so if resurrect & employ Maxwell’s demon to sort out the DWIR from the UWIR at night.

    “Heat the Balloon’s Atmosphere?”

    No, your balloon on global avg. temporal and spatial sampled is going to lose about 1K overnight.

    “Is anybody using it for anything other than measuring with a pyrgeometer?”

    On avg., I use 157 of the Trenberthian 333 to run my furnace less in the winter and to comfortably wear a less thick coat outside than if the 157 was not available to me.

  48. Tim Folkerts says:

    Bryan wonders: “There is plenty of evidence that a pyrgeometer cannot measure accurately to a resolution of plus or minus one unit out of 333

    Yet that is what the presented figure implies.

    It might have been better to give the actual uncertainties, but this is just a graphical summary of the results. I would look to the text of the paper to seek information about the uncertainties.

    Also, just because a number is written to a certain number of decimal places does not necessarily imply anything about the uncertainty. “Significant digits” are a common way (but also a lousy way) to try to indicate uncertainty. But it is not the only way.

    For example, if you look to the NIST site for the mass of the “atomic mass unit” (http://physics.nist.gov/cgi-bin/cuu/Value?u|search_for=physchem_in!) you will find it quoted as

    1.660 538 921 x 10^-27 kg.

    Someone might naively assume that the uncertainty is in the last digit (the “1″) but they would be wrong. Looking a little farther you will find that the uncertainty is much bigger — 0.000 000 073 x 10-27 kg — 73 times bigger in fact. It is common practice to write down your best estimate — even if the last 1 or even 2 digits are a bit uncertain.

  49. Tim F,

    You have the patience of Job. I don’t know how you do it, day after day, gently ad politely correcting ignorance. :-)

  50. tchannon says:

    When I threw together the head article I forgot to add a link, this one which accurately describes the obvious, a semiconductor thermoelectric device generating power under clear sky as energy passes through and generating zero under cloud when no energy passes through.

    Now what about pyrgeometer also thermoelectric device. Well apparently this generates power under cloud and no power under clear sky.
    It contain no independent power source.

    Since they are opposite one notionally must be perpetual motion.

    From CG4 manual

    What are typical values for downward atmospheric long wave radiation?

    Ambient C Overcast (Lnet = 0 Wsqm) Clear sky (Lnet -150 Wsqm)
    -20 230 80
    0 315 165
    30 480 330

    Clear sky. Day or night, doesn’t say. The text does indirectly hint various places.

    They “calibrate” at night against one of it’s own! Metrologist would go spare at this practice. At best a check calibration. Never mind, it isn’t very good anyway, I’ve been looking, lots of glossing over the awkward parts as don’t matter. Wrong advice too but hey this is science and people pay money so keep trap shut.

    Carrying on here the manual describes back to back. Do that and the result is zero output under cloud. Must be two batteries. Wink.

    The truth?
    As usually claimed the pyrgeometer is bollox. Doesn’t produce a damn thing under cloud.

    The table above gives the game away whilst omitting to spell out what is going on.

    The xxx W/sqm is a pure mathematical artefact, is computed. It’s computing the zero point based on the temperature of the body of the generator. That is why it has a temperature sensor inside the thing. That is glossed over. The reading is wot the thermometer says

    Used back to back the temperature of the body hopefully cancels.

    Go and read the maintenance manual, is incomplete but contains enough to work out a lot of it.
    I am amused at how the text dances around omitting to tell it as it is.

    As a device of it’s kind I am sure it is fine.

    Now lets get this whole thing clear in people’s minds, what really is going on. Then perhaps some progress can be made on other things.

    Ld = (Uemf/S) . 5.67e-8 . Tb (formula 2 from manual)

    where
    Ld is flux
    Uemf is thermocouple output
    S is instrument scale factor
    Tb is temperature of instrument alloy frame

    If flux is zero under cloud

    Ld = 5.67e-8 . Tb
    which is an offset

    So all we have is some black paint on top of a thermally shorting thermocouple on a metal frame. Over the top is a plastic filter. Same thing could be done in other ways but direct flux measurement, no. It’s just an SB device turning flux into power.

    The table above, note how ambient temperature is so critical. Perhaps look at the manual again or the installation sheet. Notice something missing? Why doesn’t it go on at length at how it must be mounted so that the body is at Stevenson screen temperature?

    What does that error do?

  51. tchannon says:

    tkf,
    Re: Chilbolton
    You wonder about a break in the cloud where the objective of the site is pointing upwards at those fluffy things. Did any of it show a break?

    There is even instrumentation estimating water content.

    Seems to me there is an opportunity for someone to estimate what was going on with the breakthrough of solar, I guess from top of cloud heating.

  52. Bryan says:

    A C Osborn asks

    “can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.
    “Will it provide energy to drive electric motors?”

    TJ Folkers say

    “Yes, in principle.”
    I say no because it will contradict the second law

    TJ then covers his error by saying the sink would need to be colder than the night sky producing the 333W/m2 downward

    The only practical place is deep space at 3K but that requires the 333K to go upwards.

    TJ has just invented his own perpetual motion machine.

    Since TJ admits it has never been done before (I wonder why?) then we all await his Nobel prize award.

  53. Bryan says:

    David Socrates say

    “Tim F,

    You have the patience of Job. I don’t know how you do it, day after day, gently ad politely correcting ignorance. :-)”

    Yes David all us ignorant people here at Tallbloke are grateful to you and Tim for dropping by and showing how KT97 is sound science.

    Your own version of third party insults is masterful.

  54. Bryan says:

    TJ Folkers you are in need of revising uncertainty and significant figures in reporting a final value.

    Hope this helps.

    http://nebula.deanza.edu:16080/~norona/4A_labs_files/UncertaintyandSignificantFig.pdf

  55. tjfolkerts says:

    Bryan conjectures: “TJ has just invented his own perpetual motion machine.
    If by “perpetual motion machine” you mean “a heat engine that can run as long as the sun is hot and space is cold”, then yes, this is indeed a perpetual motion machine. But there is no violation of any law of thermodynamics here.

    “I say no because it will contradict the second law.”
    Since this is your interpretation of the 2nd Law of Thermodynamics, then maybe it IS a good thing David & I are here to present some sound science.

    “The only practical place is deep space at 3K but that requires the 333K to go upwards.
    Seriously? Your only objection is the *direction* that the heat needs to move?

    “TJ Folkers you are in need of revising uncertainty and significant figures in reporting a final value.
    And Bryan, you needs to realize that the simplifications you learned in undergraduate science labs are not the only way to do things (or even the best way to do things).

  56. tchannon says, February 13, 2013 at 12:33 am

    Tim,

    I think you are being a bit too hasty in your dismissal of pyrgeometers.

    1. Your initial link to the peltier device for use as a cloud detector is an interesting and intriguing one but is not relevant since it demonstrates (correctly) the very criticism levelled here (incorrectly in my view) against pyrgeometers. Namely the peltier device measures the difference between upward and downward radiation. Great for detecting when clouds are passing over, useless for measuring downwelling radiation (the main topic here).

    2. You say: They “calibrate” at night against one of it’s own! Metrologist would go spare at this practice. True but irrelevant. A good meteorological centre would re-calibrate its device at regular intervals against a reference standard. So it is not a killer for the pyrgeometer concept as such. Also, Kipp & Zonen may well also re-calibrate their reference device at intervals against a reference standard. As a fellow electronics engineer, you will appreciate, as I do, that the initial calibration of a manufactured item to bring it into line with reality is sometimes quite a different process from subsequent re-calibrations needed to correct for longer-term ageing and drift in an instrument.

    3. You say: Carrying on here the manual describes back to back. Do that and the result is zero output under cloud. Does that surprise you? Clouds are relatively warm and low clouds are likely to be warmest of all. So isn’t it quite possible that up and down radiation would be similar under the majority of back-to-back cloud testing conditions, hence a low or minimal output from back-to-back net radiation tests? After all, according to the (apparently despised) Trenberth figures, the world mean difference between up and down radiation at the surface-atmosphere interface is only 23Wm-2!

    4. You say: The truth? As usually claimed the pyrgeometer is bollox. Doesn’t produce a damn thing under cloud. The table above [Kipp & Zonen CGR4 Manual page 28] gives the game away whilst omitting to spell out what is going on. My jaw drops open, not for the first time in this blog trail. The Table that you refer to shows a minimum of 230Wm-2 downwelling radiation when the surface air is -20degC, a healthy near-Trenberthian 315Wm-2 when the surface air temperature is 0 degC and 480Wm-2 when the surface air temperature is 30degC. Given those figures how can you substantiate your comment?

    5. You say: So all we have is some black paint on top of a thermally shorting thermocouple on a metal frame. Over the top is a plastic filter. My initial reading of pyrgeometer technology is quite the opposite to your initial reading. I get the impression that the various manufacturers are very well aware of the pitfalls and go to great lengths to avoid them. Consequently, the careful physical construction of their devices, and the associated electronic compensation mechanisms, are designed to minimise the problems you and others talk about. I am sure they achieve this with varying degrees of success, no doubt correlated to price! Kipp & Zonen quotes a 5% accuracy for their CGR4 device. Maybe they are Trenberthian-indoctrinated scumbags and are lying through their teeth and it is actually 95%. Or just maybe they can substantiate that 5% figure. I don’t know. But I haven’t read anything yet in this thread that convinces me that 5% accuracy is impossible. And 5% accuracy is more than good enough for my purposes in establishing that a world average back radiation of the order of ~300Wm-2 exists. (Remember we are working against some people who genuinely think that back radiation is ZERO!)

    And when people imply (you didn’t) that pyrgeometers are rubbish because they don’t work very well when it rains then I know that scientific and engineering reasoning is going down the plughole. Why are they surprised? For that matter rain gauges don’t work very well in the snow; and I believe wind gauges are really hopeless inside sheltered buildings. :-)

  57. A C Osborn says:

    Bryan says:
    February 13, 2013 at 8:18 am

    TJ Folkers say

    “Yes, in principle.”
    I say no because it will contradict the second law

    TJ then covers his error by saying the sink would need to be colder than the night sky producing the 333W/m2 downward

    I am not well educated, no PHD etc, but I do have a logical mind, I reached an International grading at Chess of 2100, I programmed in BASIC and still program in VBA, before retirement I was also quite adept at Problem Solving, which has procedures very similar to the Scientific Method, with one more added, not only did you have to “Solve” a problem you had to prove it by creating “Prevention of Recurrence”.

    So my Logical question is this
    1. Climate Scientists state that DWIR reaches and warms the Earth’s Surface.
    2. Tim say’s “mount a parabolic reflector aimed at the sky as the cool side (a technique that can be used to freeze water on nights when the local air is above freezing ” which I am well aware of.
    3. I have used a Parabolic Reflector (3″ Torch reflector) to collect the Sun’s rays in the UK Summer to heat a 1/4″ diameter piece of Steel to over 350 degrees C.

    So Solar energy Heats steel to 350C, Whereas DWIR Cools water to <0C, but at the same time it warms the Earth's Surface. (Cooler object heating Warmer Object)?

    Does anybody else see a Conflict here?

  58. Tim Folkerts says:

    A C,

    You are missing an important but subtle point.
    * My design for a heat energy would run very poorly on a cloudy night, because the “hot reservoir” ( the ground) and the “cold ” reservoir” (the clouds & any GHGs below the clouds) would be at about the same temperature.
    * It would run a little better on a clear night, because now the “cold reservoir” would be some combination of slightly cooler GHGs and much cooler outer space.
    * It would run even better yet if the GHG’s were completely removed so the “cold reservoir” was simply outer space (@ 2.7 K).

    Similarly, the earth cools poorly with clouds (and lots of downward IR)
    It cools more effectively on a clear night (with some downward IR from GHGs)
    It would cool even more effectively with no GHGs (and basically no downward IR).

  59. tchannon says:

    Oh dear, this is going to be hard.

    Firstly, I am struggling trying to handle life, blog housekeep and content, and taking part. If I seem to ignore anyone, sorry, not a sleight.

    I nearly commented yesterday about TKF being naughty by jumping away from what I read as a cynical comment by ACO, TKF won’t have misread, can’t be all seeing and blind. I decided not to because people bashing looks bad.

    Extracting from ACO’s comment

    ACO quotes TKF: There is plenty of data that says clouds and GHG’s radiate ~ 333 W/m^2

    ACO: So if I have a large balloon with Infra Red receptors all over it’s top surface can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.

    ACO: What height would it be best for the balloon to be at to take advantage of this energy?

    (i’ve added bolding)

    To which, extracting again

    TKF: A C Osborn asks a few questions…

    TKF quotes “So if I have a large balloon with Infra Red receptors all over it’s top surface can I get any actual “Work” out of the 333 W/m^2 when it is on the night side of the planet.

    TKF: Yes, but (as with any heat engine) only if there is a “cold reservoir” around to use. Since you want to use the “cool” atmosphere” as “hot reservoir”, then you would need something even cooler for the “cold reservoir”. The obvious choices would be cooler air higher up, or space.

    Naughty. The correct answer to the question asked is no.

    Afterwards it is of course permissible to relate how a different situation would work.

    TKF : I am now tempted to do this simply to prove it can be done! And it would be cool to own a sterling engine.

    TKF rhetorical paraphrase: “What height would it be best for the balloon to be at to take advantage of this energy?
    TKF : The most important factor would be to get above the clouds (or do it on a clear night). That way the downward IR would have more of the 2.7K background radiation and less of the much warmer atmospheric radiation.

    At this point it looks ugly, TKF having failed to say No, now demonstrates he does understand but makes a further mess for himself getting flak as a result.

    Worst of all “(or do it on a clear night)” when there is no 333. Or perhaps CO2 is a wonder gas, it’s still there, a travesty with all this technology, must be hiding in the dark.

    He brings up the subject of cloud declaring needs to be above that, mention deep space but omits to mention he just wiped out the 333 from above, in addition fails to admit the at night is the result of cloud, no cloud situation is completely different.
    He then proceeds to invert the balloon above the clouds… flak then appears from eg. Bryan (who is close to being snipped as impolite, seriously considered, what starts bun fights)

    I hope we can resolve all this because only then can the whole general problem go anywhere. All part of why I rarely take part in “radiative crap” (self quote), to me is pig wrestling. I’m either way behind or way ahead, same place I ain’t.

    Aside: N% is as ever a problem, Stirling isn’t a lot of use, in practice nearer Rankine is used with extremely large turbines where massive energy flow at very low temperature drop is all there is.

  60. A C Osborn says:

    tchannon says:
    February 13, 2013 at 2:11 pm

    OK, no more questions, I should have asked on the old Thread anyway and not this one.

  61. Tim Folkerts says:

    PS. A note on names (which seems to be getting confusing).
    * I am “Tim Folkerts” (with a “t” near the end).
    * I am also “tjfolkerts” or “TJF” or “Tim F”
    * There is also “tchannon” who is “Tim Channon” who is a moderator
    * There is also “Tim Cullen” who posted on this thread.

    So …
    * we have three “Tim”s on this thread, two of whom are “Tim C”.
    * I have not been responding to comments to “TKF” because I thought that was someone else, but it seems these were directed to be me — I will have to go back and look later when I have time.
    * I may well have attributed a comment or two to the wrong “Tim C” in this thread — I don’t think I was paying enough attention to “Cullen” vs “Channon”.

  62. steverichards1984 says:

    Re the CGR4, I see that they use a thermocouple and a thermistor, and the thermistor can be replace with a PT100 sensor!

    Why not use just a PT100 on its own?

    It is more accurate than a thermocouple, requires no special wiring/cold junctions etc

    They already have wiring in place (in the manual, page 27) for a 4 wire PT100, so that would give a much more accurate reading.

    I will be impressed if the thermoelectric voltages in the connections to the display/recording device does not influence the value output from the complete system.

  63. Tim Folkerts says:

    And a bit of a peace offering. I was responding to the generalized of the question — “Can the IR from the atmosphere be part of a heat engine?”. The answer is clearly yes to the general question. I was not looking at the details like where the sensors were or what sort of sensors they were or how hot the balloon was. In specific circumstances, it is indeed quite possible not to be able to use the “333 W/m^2 coming from some conglomeration of clouds and GHGs at varying temperatures” in specific circumstances.

    Now back to work …

  64. Max™ says:

    A safer way to phrase that is as follows:

    It is not possible to extract work from downward infrared radiation to run a heat engine, unless there is a reservoir cooler than the atmosphere available.

  65. Stephen Wilde says:

    How does a pyregeometer distinguish between radiation flowing toward it from a distant point as distinct from radiation released as a result of the temperature of the molecules all around it ?

  66. A C Osborn says:

    Further to Stephen Wilde’s question -
    What value do you get from a pyrgeometer when you point it directly at the Sun?

  67. tchannon says:

    Oh dear, sorry. Names. I much prefer threaded but this has been discussed and was not wanted by a number of parties.

    I use an awkward handle as the solution to the clash of name problem. I don’t like it but how it is.

    At the moment I am try to split the circularity of atmospheric argument, something has to break.
    To illustrate and with no intent other then showing how the whole thing revolves

    “Similarly, the earth cools poorly with clouds (and lots of downward IR)
    It cools more effectively on a clear night (with some downward IR from GHGs)
    It would cool even more effectively with no GHGs (and basically no downward IR).”

    The last sentence is where I dispute, the atmosphere will heat without ghg, will spin back around to dynamic body, lapse profile, convection, water cycle and there we are again.

    Cleaving the measurement of flux is an attempt to gain more clarity.

  68. thefordprefect says:

    Stephen Wilde says: February 13, 2013 at 3:49 pm
    How does a pyregeometer distinguish between radiation flowing toward it from a distant point as distinct from radiation released as a result of the temperature of the molecules all around it ?

    It responds to all molecules that radiate within its optical bandwidth. O2 N2 etc absorb / radiate at wavelengths outside the bandwidth. In fact the path lenght of radiation at STP is small so most radiation will be from close molecules.

    A solid object would radiate as a BB and would therefore be within the bandwidth- hence it is important to keep solid objects to a minimum and preferably a long way away.

    Conduction to non-GHGs will heat the unit but this would be nulled by temperature measurements.

  69. wayne says:

    Everyone says math and experiment, here’s one that might answer the burning question of what pyrgeometers are actually measuring.

    An Inexpensive Experiment to Measure Back-Radiation:

    ● Take two identical small boxes, 6″×6″×6″ should do.

    ● Insulated each very well on five sides leaving the other open.

    ● You need two 6″×6″×2″ weighed blocks of dry ice that will be placed at the bottom of each box held in place by a course screen, chicken wire should suffice.

    ● Over the open side of each place an IR transparent membrane, very thin Mylar or a plate of rock salt. Poke a small hole at the top and bottom of each box to guarantee identical pressure inside of each.

    ● Each box will quickly fill with pure carbon dioxide.

    ● Place each one meter from the surface on a clear dark night preferable when the relative humidity is low. One will face upward toward the open sky, the other toward the Earth.

    If back-radiation has power, if back-radiation does really exist and waves do not cancel, that back-radiation is quickly absorbed and thermalized to perform work sublimating dry ice, you should observe that the block of dry ice facing the Earth and the block facing the sky are close to the same size (slight 63 W/m² difference), the one facing the Earth being the somewhat smaller.

    If back-radiation has no power, if back-radiation does not have a real existence and the e/m quanta waves are being simply cancelled or are standing waves who have no power at the attachment ends, that back-radiation is never actually thermalized to work in any way, you should observe that the block of dry ice facing the Earth quickly (may take an hour) disappears and most of that in the upward box remains sizeable.

    If you have measured and weighed each carefully and recorded the elapsed time and ambient temperature, you should be able to calculate a pretty close value of how much back-radiation is beaming downward on you every night from the sky.

    You might want to repeat this experiment on an overcast night to show whether the two blocks of dry ice end up close to the same weight or not.

    It also might be a good idea to move the location of whatever is holding the boxes off the surface so that the surface maintains its temperature and does not itself get colder. We will just assume the vast sky cannot be cooled by a mere 2 kg of dry ice to any measurable degree.

    The science:

    Dry ice has a density of ~1500 kg/m³
    Dry ice mass 6″×6″×2″ is 1.77 kg
    Dry ice sublimates at -78.5 °C (194.65 K)
    Assumed ambient surface temperature 16°C (289.15 K) or equivalent, 396 W/m²
    Assumed back-radiation 333 W/m², equivalent@ε=1 of 3.7 °C (276.8 K))

    The differential between the dry ice and the surface is (289.15^4-194.65^4) K or 314.7 W/m². The difference for the sky pointing box is 251.5 W/m², a difference of 314.7-251.5 W/m² or 63.2 W/m² as expected.

    Excuse the excess of precision, it is all my calculator’s fault. ;)

    One should sublimate much more than the other if back-radiation has little or no actual power or be close to the same (just 63.2 W/m² difference) if back-radiation does beam down from the sky upon us. I would like to know and this should supply the answer one way or the other.

    Does anyone see any immediately refutable flaws before spending any time and money? Can someone do this? Sorry, I am unable at this time or I would do just this.

  70. wayne says:

    It might be easier to do this at first with just one box and start with the sky pointing case. It the box freezes up, ice forms on the Mylar and the 333 W/m² of sky energy cannot even melt the ice, I would say the experiment was just answered. But if this happens, go ahead and turn it upside down toward the warmer Earth at 396 W/m² and see if it can not only melt the ice but starts to sublimate the dry ice. That might be one result. Maybe not.

    You know, you might be able do this without any measurements at all. Anyone agree?

  71. Stephen Wilde says, February 13, 2013 at 3:49 pm: How does a pyregeometer distinguish between radiation flowing toward it from a distant point as distinct from radiation released as a result of the temperature of the molecules all around it ?

    Hello Stephen,

    The Kipp & Zonen CGR4 pyregeometer seems to be the top of the range professional model. You can download the pdf instruction manual from:
    http://www.kippzonen.com/?product/17152/CGR+4.aspx

    It is extremely readable and well worth the effort. Most of the basic information is on Page 25, viz:

    “CGR 4 has been designed for scientific measurements outdoors of downward atmospheric long-wave
    radiation with extremely high reliability and accuracy.

    CGR 4 provides an output voltage that is proportional to the net radiation in the far infrared (FIR). By
    calculation, downward atmospheric long-wave radiation is derived. CGR 4 has an integrated temperature sensor to measure the housing temperature.

    CGR 4 uses a specially designed silicon meniscus dome. Although the window is not hemispherical, CGR 4 has a 180° field of view with good cosine response. A hard-carbon, diamond-like, coating protects the outer surface of the window and smoothes the spectral response. On the inside, a solar blind interference filter blocks all short-wave solar radiation.

    The solar radiation absorbed by the window is conducted away into the housing very effectively, by a
    unique construction. Even in full sunlight the window heating offset is very low compared to that of other pyrgeometers on the market. This allows accurate daytime measurements without the need for a tracking shading disk. It also eliminates the need for window heating compensation by using the correction formula.

    The special features of the CGR 4 are:

    - Sensitive to infrared radiation in a wavelength range from 4.5 to 42 μm.
    - Extremely low window heating offset.
    - 180° field of view with good cosine response.
    - Diamond-like coating for optimal protection against environmental influences.
    - Low temperature dependence of sensitivity.

    Looks like a really professisonal job to me. But they could be lying through their teeth and quite possibly are an offshore subsidiary of Trenberth Inc.

    Must keep the paranoia flying. :-)

  72. Tim Folkerts says:

    Wayne,

    Let me suggest a couple things.

    * The top of a car often frosts before the sides. The side of a car facing AWAY from buildings often frosts before the side facing TOWARD buildings. This would be due to the exact idea you are discussing — the top side is receiving radiation from the cold atmosphere, while the sides are receiving radiation from the warmer ground and buildings.

    * The technique of freezing water with a parabolic mirror pointing toward the sky also relies on the fact that the radiation from the sky is less than the radiation from the ground.

    * I would line the boxes with aluminum foil (or ‘aluminium’ for our British friends). This will limit the IR that would come directly from the walls of the box.

    * Pointing one box up and one box down would introduce some potentially significant differences (eg convection). You might instead put a sheet of plywood a couple feet above one of the boxes — it should be pretty close to the temperature of the ground due to the local atmosphere. This way they would all be in the same orientation.

    * The dry ice introduces an “out” for those who “don’t believe in back-radiation”. You will STILL be looking at radiation from a “warm” region (the clouds and GHGs near the surface), to a cold region (the dry ice). So most “back-radiation skeptics” will (I suspect) agree that radiation can go from the atmosphere to this colder dry ice.

  73. wayne says:

    Be out all p.m. Can’t wait to see the remarks. The more I think on it, the better that experiment appears to be.

  74. Bryan says:

    A C Osborn says

    “So Solar energy Heats steel to 350C, Whereas DWIR Cools water to <0C, but at the same time it warms the Earth's Surface. (Cooler object heating Warmer Object)?

    Does anybody else see a Conflict here?"

    Yes you have spotted a whopper of a conflict.

    TJ Folkers has on many occations said that the back radiation 'warms' the Earth surface.

    Now he proposses to collect and focus this radiation.

    So guess what he says the result of collecting and focusing this warming radiation?

    To make the temperature very, very, very, cold !

    It just shows you IPCC advocates will believe any old rubbish.

    This is what TJF calls sound science.

  75. tchannon says:

    David Socrates,

    Calibrate against what? I think that needs answering, how is absolute measurement of flux done.

    It is a glorified thermometer, after the horse entered the stable.

    What I have identified as a major problem is the flux reading is directly related to the temperature of the device where that is an omitted variable/function from the actual temperature relative to the flux. Vaguely 5Wsqm per degree error.

    The table is showing the temperature coefficient.

    Where is the device, sitting with the ground frost, on a heated cabin, etc.,is it sun heated, in the wind, etc.
    Even at the vague head height of Stevenson there is a serious problem with representativity, of where is the assumed outbound being bounced back, how do we know it is the same temperature as the body of the device. (also applies to a full device as a problem)

    It is the ground which is supposed to be of interest and that is not the air temperature. Can’t read this from air temperature thermometers.

    In addition the usual exposure matters apply including the horizon.

    WMO 1064, “DIRECT RADIATION AND SUNSHINE DURATION” covers this.

  76. tchannon says:

    Stephen Wilde says, February 13, 2013 at 3:49 pm: How does a pyregeometer distinguish between radiation flowing toward it from a distant point as distinct from radiation released as a result of the temperature of the molecules all around it ?

    I can try. Conduction cancels by touching, radiation travels without touching, flown in.

    I suspect it would be more sensitive if the device was under hard vacuum but that means producing a mechanically strong window transparent to IR.

  77. Bryan says:

    TJ Folkerts has shot himself in the foot with his warming radiation device that does the opposite.

    http://solarcooking.org/radiant-fridge.htm.

    The device will freeze water that otherwise would be above the freezing point, it is true but unfortunate for the greenhouse theory.

    Another strange result is that on cold nights the temperature inside a greenhouse can drop below the ambient temperature outside.
    What creative excuse will greenhouse advocates invent to explain this?

    http://www.hort.cornell.edu/hightunnel/about/research/general/penn_state_plastic_study.pdf

    This paper also back up the famous Woods experiment although that was not the intention.

  78. Tim Cullen says:

    Tim Folkerts says: February 12, 2013 at 2:20 pm
    The point is that we are NOT facing insufficient data

    I will be more specific then: Insufficient and Bad data

    http://tallbloke.files.wordpress.com/2012/11/clear-cloudy.png

    When comparing the clear and cloudy spectrums it is evident:

    Clouds absorb UVB and emit visible light and infrared radiation.

    This is additional observational evidence that indicates:

    The atmosphere transforms energy.

    This was observed by Sir David Brewster back in 1836:

    Sir David Brewster (1836) found that certain lines had strengths that varied with the sun’s elevation and with the seasons. He correctly ascribed these ‘atmospheric lines’ as originating in the terrestrial atmosphere.

    http://tallbloke.wordpress.com/2012/11/22/tim-cullen-the-problem-with-tsi-total-solar-irradiance/

    David Socrates says: February 12, 2013 at 3:28 pm
    Surely you don’t dispute the solar constant measured by satellite instrumentation.

    You can be assured there are problems with Satellite TSI:
    http://tallbloke.files.wordpress.com/2012/12/image10.jpeg
    http://tallbloke.files.wordpress.com/2012/12/image11.jpeg
    http://tallbloke.wordpress.com/2012/12/09/tim-cullen-1366-and-all-that-the-secret-history-of-total-solar-irradiance-tsi/

  79. Bryan says:

    David Socrates

    Seems quite happy with the 333W/m2 figure for DWIR measured using a pyrgeometer.

    Anyone who doesn’t like this figure must supply their own.
    Otherwise its ‘hand waving’

    He does not seem to appreciate that this instrument has a 50 year history of false dawns only to have users hopes dashed as its inherent bad science gives unreliable readings

    Read someof the latest batch

    Page 20
    http://www.arm.gov/publications/programdocs/doe-sc-arm-p-05-011.pdf

    page 1

    http://www.arm.gov/publications/proceedings/conf16/extended_abs/stoffel_t.pdf

    Pointing out the inherent contradictions or falsification of a theory or experiment has a long history and It is sufficient in itself.

    It does not require the critic to have an alternative theory or value

  80. thefordprefect says:

    tchannon says: February 13, 2013 at 6:15 pm
    David Socrates,

    Calibrate against what? I think that needs answering, how is absolute measurement of flux done.

    It is a glorified thermometer, after the horse entered the stable.

    The literature suggests that calibration is done using a heated sphere with the sensor poking in at the bottom.
    The sphere radiates at a calculable w/sqm (temperature and BB assumed.
    The device gives a voltage out according to the received flux.

    The devices are designed not to be temperature sensitive -40C to 80C i think i have read gives about 1% error

    So as a thermometer it is useless.

    These devices or similar have been around for eons(!) long before agw and I do not see scientists able to propagate an error/fraud/misconception for so long without some 19th/20th C scientist calling their bluff.

  81. thefordprefect says:

    Bryan says:
    February 13, 2013 at 7:11 pm

    Reading your refs it appears that the error is+-3 to +-4 w/sqm since 2005, and earlier to 2002 results are to be corrected.

    Even at worst case an error of +-12w/sqm still shows a DLWIR of at least 318w/sqm!

  82. Tim Folkerts says:

    [[ Banging my head against a wall ]]

    OK .. let me make one more attempt. Downward IR really does “warm” objects and everything I have said is consistent with such a claim!

    Suppose I have a a flat sheet 1m x 1m of material that is a blackbody. The sheet is thin enough that the top and bottom will be at the same temperature. Let’s also ignore conduction to/from the surroundings (perhaps the sheet is suspended in a vacuum by thin strands of silk).

    We have available the following “heaters”:
    * a blackbody at 300 K = 459 W/m^2 (eg the ground)
    * a blackbody at 280 K = 349 W/m^2 (eg a layer of clouds ~ 3 km above the ground)
    * a graybody at 280 K = 250 W/m^2 (eg GHGs in the atmosphere)
    * a blackbody at 2.7 K = 0 W/m^2 (eg outerspace = no GHGs & no clouds (& no aerosols) in the atmosphere)

    We also have some large mirrors that reflect IR very well (eg Al).

    What will the temperature of the sheet in the following circumstance?

    * Space on both sides = 0 W in
    → 2.7 K
    * Space on one side + GHG on the other = 250 W in = 125 W out from each side
    → 217 K = 214 K warmer

    GHG on one side; space on the other = 250 W in
    → 217 K
    GHG on one side + GHG on the other = 500 W in
    → 258 K = 41 K warmer

    Clouds on one side; space on the other = 349 W in
    → 234 K
    Clouds on one side + GHG on the other = 599 W in
    → 270 K = 36 K warmer

    Ground on one side; space on the other = 459 W in
    → 252 K
    Ground on one side + GHG on the other = 709 W in
    → 281 K = 29 K warmer

    IN EVERY CASE, HAVING GHGs INSTEAD OF OUTER SPACE PRODUCES A WARMER TEMPERATURE FOR THE OBJECT.

    Now, it is certainly true that removing the strong radiation from the ground and replacing it by weaker radiation from GHGS (for example by putting reflectors under the sheet to block IR from the ground and reflect in IR from above to make a “radiant refrigerator”) can cool the sheet (from 281 K to 258 K in the example above). This would, for instance allow us to freeze water into ice.

    BUT WHAT IS THE ALTERNATIVE with no GHGs? If you leave the rest of the experiment alone, the no-GHG-sheet would be receiving IR only from space, and the sheet would cool to the temperature of space = 2.7 K! Again GHGs produce warming over the no-GHG alternative.

    All the objections others have made in previous posts are apples-to-oranges.

  83. Bryan says:

    TFolkerts

    You have 333 W/m2 DWIR as David and KT97 say ‘warm’ the warmer Earth. surface.
    You then use a parabolic mirror to focus the warming rays to some extent say 400W/m2

    Surprise, surprise!

    The concentrated warming rays freeze water.

    When will you accept that reality does not correspond to your radiation obsessed theories.

    Have you worked out yet why the air temperature inside a greenhouse is colder than the ambient outside air temperature on some cold nights?

  84. tchannon says:

    Ford, odd then the manufacturers do not do that. No mention of a calibrator. I want to know why, not that an answer is going to appear.

    The problem I am seeing is fundamental but outside of the immediate. If the device was used to purely proxy thermal flux the problem would be far more apparent. On it’s own it would give a value but that could not be readily split.

    It’s the dubious practices in so much of this stuff which so troubles me.

  85. Bryan says:

    thefordprefect

    The 2005 paper (page20) tells them to suspend taking readings until the calibration issue was sorted out.

    The 2006 paper says(page 1) there is a persistent bias of plus or minus 5 and – 12W/m2

    So a night time real value of 100W/m2 would be read anywhere from 93 to 83 W/m2

    If you look at the Davos 2002 paper the user group were overjoyed because they got the various pyrgeometers to read the same value when pointed at the same sky.
    To get this they had to modify the manufacturers formula.

    This episode unfortunately turned out to be another false dawn as the 2005 and 2006 papers confirm

  86. tchannon says:

    TF
    Some time ago somewhere else, private discussion group I produced a simile vaguely of that nature. To my complete surprise a few days later a well known name came up with the same thing on their high profile blog. One snag, it was different in a critical detail. Given who they are I could say nothing but they share your view on radiation. I’m curious on why.

    I’m not going to do anything right now, too much else attention needing but I’ll note that as a possible basis for a discussion article. Would need drawings, takes time.

    I think one of the headbangers is language, there are sharp differences of comprehension, both correct. You are using the word warming I think carelessly when you do not mean warm as an action. Putting a blanket on something does not warm it, the something warms itself as a result of reduced loss rate.
    This is highlighted more when gradients are considered, for example, reducing a thermal load on a surface will lead to a rise in the temperature of the surface even though the body has a fixed temperature (is controlled), there is a surface gradient.
    In the case of atmosphere there are a variety of ancillary factors complicating things as I think might become clear if that lot can be drawn up.

    Where and how we differ, pass. I think we do differ over no ghg necessary to gain a hotter atmosphere, other processes can do that on their own. What does gas phase only ghg do? I don’t know, too many confounding things.

    I do consider attenuation to be a more useful way to consider the effect of loss or gain moderating media. This avoids bothering with radiative balance, an internal detail.

  87. Bryan says:

    I said earlier

    “There is plenty of evidence that a pyrgeometer cannot measure accurately to a resolution of plus or minus one unit out of 333

    Yet that is what the presented figure implies.

    1/333 = 0.003 or 0.3% relative uncertainty for the 333W/m2 figure

    I don’t think so

    Why does Trenberth put such unsubstantiated 3 figure accuracy numbers out?
    Its to imply accuracy where it doesn’t exist.”

    Yet Tim Filberts makes lame excuses for KT97
    This falls into a familiar pattern for Tim.
    You will find him defend every last dot and comma of IPCC pseudoscience.

    Even if we accept an absurdly low value for uncertainty say 5%

    Then the real value could be anywhere between 316 and 350

    So what are the last two digits in 333W/m2 doing there if not to claim an accuracy that is not there.

    Tim thinks 333W/m2 it all right in this ‘pass with a shove’ branch of pseudoscience.

    In a future experiment a climate science researcher measures the value of a resistor .

    The voltage is 10 Volts and the current is 3 amps

    The researcher calculates the resistance 3.333333333333………….to infinity ohms

    That’s the kind of reporting values that Tim defends.

  88. Bryan says, February 13, 2013 at 7:11 pm

    In defence of your position that pyrgeometers falsely report ~300wm-2 for downwelling LW radiation, you provide two links to professional literature discussing an operational calibration problem that occurred between world standard pyrgeometers several years ago and involved discrepancies only of the order of 5 to 15Wm-2.

    It is very difficult to know where you are coming from. You are obviously very exercised by the idea that the Trenberth figure of 333Wm-2 is wrong but you won’t say how wrong you think it is.

    (1) If your argument is that it might be 5 to 15Wm-2 wrong then I would agree you could well be right. No instruments are perfect and it would not of the slightest concrn to me if the figure were to be modified by that small percentage.

    (2) On the other hand if you are suggesting that downwelling LW IR is ZERO then I will be laughing my socks off.

    You have gone on and on about this now for days without EVER explaining what scale of discrepancy you are concerned about. Until you do, it is impossible to have any meaningful dialogue with you.

  89. tjfolkerts says:

    tchannon says:
    “Given who they are I could say nothing but they share your view on radiation. I’m curious on why.”
    Maybe because the mystery blogger and I both understand the physics of thermal radiation? ;-)

    “You are using the word warming I think carelessly when you do not mean warm as an action.”
    I admit that the language is a challenge — “warm” because it is so vague, and “heat” because it is so specific. I would still say that since the atmosphere actively sends energy to the surface via IR photons, that the atmosphere is indeed “warming” the surface. (But I admit that there are other equally reasonable interpretation of the concept “to warm”).

    “I think we do differ over no ghg necessary to gain a hotter atmosphere, other processes can do that on their own.”
    Lots of things affect the temperature. But nothing I can think of besides IR properties of the ToA will allow the surface to reach an average temperature above 255 K (given the current albedo). GHGs — along with clouds and aerosols — are part of the radiation balance that allows an average temperature above 255 K.

    Let me turn the question around to you. Are you saying that you think IR properties of OTHER THINGS (clouds and/or aerosols) are responsible for the warming from 255K? Or are you saying that even in an atmosphere that is completely IR transparent that the average surface temperature could be above 255K do to some “other processes”? Those seem to be the only two options consistent with your statement.

  90. Bryan says:

    David Socrates says
    “In defence of your position that pyrgeometers falsely report ~300wm-2 for downwelling LW radiation, you provide two links to professional literature discussing an operational calibration problem that occurred between world standard pyrgeometers several years ago and involved discrepancies only of the order of 5 to 15Wm-2.”

    My quote

    “The 2006 paper says(page 1) there is a persistent bias of plus or minus 5 and – 12W/m2″

    2006 is not several years ago in the history of this defective device.
    They first appeared in 1950 and have never worked properly since.
    I can find no more recent information on its calibration problems.

    The fact that it fails to perform as the theory suggests indicates that aspects of the theory are not correct.

    You say

    “On the other hand if you are suggesting that downwelling LW IR is ZERO”

    Where did this absurd idea come from?
    Nothing I have written indicates that.

  91. wayne says, February 13, 2013 at 5:06 pm: Everyone says math and experiment, here’s one that might answer the burning question of what pyrgeometers are actually measuring.

    All power to your experiment but it won’t settle the question of whether pyrgeometers are accurate because it will not give a quantitative result. Pyrgeometers do give quantitative results that are most probably accurate to 5 or 10%. Several world standard reference sites have been measuring downwelling LW radiation for years using pyrgeometers and their results agree well. Bryan [February 13, 2013 at 7:11 pm] managed to dig up a report from years back when they discovered they had a discrepancy between sites of the order of only 5 to 15%. Why did they bother? Because they are professionals using professional instrumentation and wanted to get to the bottom of a calibration problem even though it was of a comparatively minor nature. How do you think Trenberth and his colleagues came up with the 333wm-2 figure? They did a re-analysis of all available sources. Yes they might be wrong by 5 or 10% but is that going to change the face of climate science? I think not.

    You have to understand what is going on here. Some people are fixated on the idea that downwelling LW radiation is a complete fiction. They are horribly misinformed because it has been measurable (and measured) for years, albeit with some instrumentation uncertainty. But they won’t give up, whatever evidence you present to them. They just say things like ‘pyrgeometers are bollox’.

    Very scientific. :-)

  92. Bryan says, February 13, 2013 at 11:19 pm: You say “On the other hand if you are suggesting that downwelling LW IR is ZERO”. Where did this absurd idea come from? Nothing I have written indicates that.

    Good progress. Now tell us all exactly how bad you think pyrgeometers are at measuring downwelling LW radiation. I suggest 5% error for the best pyrgeometers available. What’s your figure?

  93. Max™ says:

    What if I said “downwelling IR is -63 W/m^2″?

  94. tchannon says:

    Question. Where does the 333 originate?

  95. Max™ says:

    From a blue layer of haze marked “Greenhouse Gases”, I think.

  96. tchannon says:

    There was a slight frost before dawn here, uniform weather conditions, still unbroken low cloud, been so for days, temperature hovering just above zero. I hazard a guess that is the cause of the dip.

    Chilbolton Obs.

    Shown out of interest.

  97. tchannon says: February 13, 2013 at 8:35 pm

    Ford, odd then the manufacturers do not do that. No mention of a calibrator. I want to know why, not that an answer is going to appear

    fig 3a 3b 3c in this:
    http://www.arm.gov/publications/proceedings/conf16/extended_abs/stoffel_t.pdf

    page 16 etc of this
    http://www.arm.gov/publications/programdocs/doe-sc-arm-p-05-011.pdf

    Expected error is of the order of 8w/sqm from reference bb cal to sky calibration. (2005) – at this time they were still deciding on a reference standard for universal calibration.

    The real reference is a Absolute Sky-scanning Radiometer Comparisons (IPASRC) but using NREL BB to calibrate 12 PIRs produced readings within +-3w/sqm.

  98. tchannon says:

    Thanks.

    Wrote some but perhaps not now, maybe tomorrow, less likely to write upsetting notes. Shall we say I am amused.

  99. wayne says:

    Ok, just back… (hate those trips to the dentist ;()

    Hmm… no takers so far. Konrad, right up your alley. You seem to already have everything but the dry ice.

    Dry ice was chosen, even thought liquid nitrogen would have been better, but couldn’t envisionalize how to easily hold liquid nitrogen in place at the bottom of the boxes with chicken wire. ;) Really, because the substance had to be far below the temperature of either radiative powers being tested.

    Come on, surely someone has a small Styrofoam box in their garage, a box that Xxxxxx came packed, maybe from FedEx? Surely someone can find a place to purchase a pound of dry ice. I do hope. Use toothpicks instead of chicken wire that might now be rather hard to come by in our rapidly de-industrialized world… where there is no ability to test science for there nothing available to the commoners to use in the test.

    Waiting. :)

  100. Bryan says:

    David S

    Says
    “Good progress. Now tell us all exactly how bad you think pyrgeometers are at measuring downwelling LW radiation. I suggest 5% error for the best pyrgeometers available. What’s your figure?”

    After making a completely unfounded allegation and after giving you evidence from 2006 by users of up to 17W/m2 uncertainty you appear not to have read any of it.

    Work it out for yourself

    17/reading then multiply by 100 to get percentage uncertainty.

    Good progress my foot.

  101. thefordprefect says, February 14, 2013 at 3:06 am

    Exactly. Precisely.

    Thanks for an input of sanity into a hitherto bizarre debate. Fact is, there’s likely nothing wrong at all with modern pyrgeometers, in particularly the leading professional device, the CGR 4 from Kipp & Zonen, used all over the world by monitoring stations. I have no proof of their claim that it is accurate to 5% but I wouldn’t be at all surprised if that figure were to be substantiated after further investigation.

    A week ago I knew very little about pyrgeometers (nothing actually). But, thanks to Tim Channon and this blog, we now all know a lot more. Or at least some of us do, those of us who…

    1. have appraised in some detail the underpinning technology and its application in a modern professional product;
    2. have discovered that international standards ARE being observed and applied (yes, due indeed to professional diligence and cooperation leading to improvements a few years back);
    3. are not sufficiently paranoid (on good days :-) ) to think that Kipps & Zonen are in league with the devil incarnate;
    4. appreciate that the world mean figure for back radiation between atmosphere and surface is of the order of 300Wm-2 but do not quibble over the exact number (as if it mattered one jot in this woolly, slipperly, imprecise climate business);
    5. appreciate that pyrgeometers don’t work very well in the rain but that this does NOT invalidate them as accurate measuring devices

    Tim Channon’s discovery of the UK’s Chilbolton Observatory with its ‘real time’ graph of the downwelling radiation hovering at around the 310Wm-2 mark is just the icing on the cake. What a marvellous find that was, cutting through swathes of armchair obfuscation. (See Tim’s graph just above, February 14, 2013 at 2:46 am, taken from the site yesterday.) And Chilbolton is only just over an hour’s drive from where I live in Oxfordshire. I have already contacted them, hope to visit them if they agree, and will respond with a proper professional report in due course.

    Why am I going to all this trouble? Is it because I have suddenly developed a passion for pyrgeometers?

    Nope.

    It’s because I need to knock firmly on the head the prevalent idea among many AGW skeptics that back radiation from the atmosphere to the surface exists and that my fellow skeptics who don’t believe it exists should just get over it. Otherwise we will never move forward to tackle the real issues, as we are attempting to do over on my TB blog article from which Tim Channon helpfully spun off this side investigation.

  102. Bryan says February 14, 2013 at 8:02 am

    Brian,

    That’s a typical non-reply to my pointed question. I presume you wrote it before reading
    thefordprefect’s response on February 14, 2013 at 3:06 am.

  103. Bryan says:

    David Socrates

    You obviously have never handed in a lab report.

    The most recent (2006) pyrgeometer calibration review said that a persistent bias of up to – 17 W/m2 was present.

    So the percentage error has to be worked out for a particular reading.

    So typical daytime value = 17/300 = 0.06 = 6%
    typical nighttime value = 17/200 = 0.09 = 9%

    Now if a doubling of atmospheric CO2 produces one W/m2 as claimed then uncertainties of 17W/m2 in one value make fine calculations like KT97 futile.

  104. steverichards1984 says:

    This paper http://www.arm.gov/publications/proceedings/conf16/extended_abs/stoffel_t.pdf posted by ford is most illuminating.

    I always thought (read) the BBs were a theoretical concept, that you can manufacture one that is near to being a BB but it will not be a perfect BB.

    We now have scientists constructing BBs to calibrate pyrgeometers.

    They document a range of problems trying to get measurements to agree with theory, then they ‘adjust’ the calibration to get it as close as possible to what they believe it should be!

    What happened to traceable standards? the amp, the ohm, etc where units of measurements could either be absolute or derived. Either way, they had a firm physical or mathematical under pinning.

    Are any traditional measurement houses involved in developing accurate instruments in this field?

  105. Tim Cullen says:

    Bryan says: February 14, 2013 at 9:11 am
    uncertainties of 17W/m2 in one value make fine calculations like KT97 futile.

    And “Trenberth et al., 2009” shows a Net absorbed 0.9 W/m2 :-)

    http://malagabay.files.wordpress.com/2013/01/celebrating-changing-climate-science.png

  106. AlecM says:

    Those on this thread who imagine that because a body has a particular temperature, the power output calculated for that temperature from the S-B equation is a real energy flux are wrong. It is the potential energy flux the body would radiate to a sink at absolute zero.

    FOR ANY OTHER TEMPERATURE SINK, THE SINK EMITS AN OPPOSING FLUX WHICH REDUCES THE NET FLUX.

    This is taught to every physical scientist as the difference between two S-B equations including emissivities and absorptivities plus geometric view factor. Only Climate Alchemy teaches that the notional flux the atmosphere would emit to absolute zero adds to the net IR emitted by the surface of the Earth to create the black body emission claimed by Houghton following Aarhenius.

    This was debunked at the time by Neils Bohr. It recreates the imaginary BB flux from the Earth’s surface. The real net IR is that BB potential emission – ‘back radiation’. To think otherwise is ludicrous.

    This BB radiation is the supposed to be absorbed by atmospheric GHGs leaving the OLR.

    Ramanathan’s G=Surface emission – OLR is 157.5 W/m^2 (Trenberth et. al. 2009). Of this only 23 W/m^2 is real. 333-238.5 = 94.5 W/m^2 is imaginary = MOD(back radiation)- MOD(OLR) (used to balance top and bottom of atmosphere 360° emission to complete the two-stream approximation at the boundaries). To this must be added the Atmospheric Window emission from the Earth’s surface, 40 W/m^2, which cannot be included in MOD(OLR).

    So, 134.5 W/m^2 is imaginary warming: it’s offset by using tricks like double real low level cloud optical depth in hind casting, the cause of imaginary positive feedback.

    Because of a quirk of physics, very easily explained, an atmospheric heterogeneity ‘sees’ the thermal GHG output of a self-absorbing GHG band at the black body level. This means that at the Earth’s surface the BB emission in those same wavelengths is annihilated, Poynting’s Theorem, from Maxwell’s Equations.

    So there is no net surface emission at the 15 micron CO2 band. There can be no direct thermalisation of surface IR because of Local Thermodynamic Equilibrium plus quantum exclusion. Other effects occur as well which transfer energy to the atmospheric window.

    Above cloud level thermalisation falls off so Kirchhoff’s Law of Radiation ceases to apply by TOA except for stratospheric emission.

    The problem is the S-B equation: because you calculate net flux by the difference of the two opposing Planck Irradiation Functions, the dim imagine back radiation is real. It does not exist except as information in the electromagnetic continuum. Only when the two Poynting Vectors combine vectorially is there any quantised energy transfer.

    When the bodies are of identical temperature and the same emissivity, the PVs annihilate. If they did not there could never be radiative thermal equilibrium.

    As a final point,. Houghton was wrong to claim grey body atmosphere. The Atmospheric Window means heat loss at night in clear skies. ground frost, fog, dew is a heating mechanism opposing this. If there were ‘back radiation’ these effects could not exist except at the poles.

    Bottom line – CO2-AGW is impossible. There is no GHG blanket. The 0.9 or is it 1 W/m^2 abyssal heat is a last desperate throw of the die.

  107. Bryan says, February 14, 2013 at 9:11 am:

    You obviously have never handed in a lab report.

    Wrong! I worked for a decade in R&D at the beginning of my career in telecommunications, electronics and computer systems design. My R&D phase was in industry not academia – so I am grounded in reality as well as in process and procedure. :-)

    Now if a doubling of atmospheric CO2 produces one W/m2 as claimed then uncertainties of 17W/m2 in one value make fine calculations like KT97 futile.

    Ah! Light at last. I think I now understand the context in which you are arguing – which is just different from mine and not at all wrong.

    Yes, I agree that one would need an incredibly accurate pyrgeometer (to a fraction of 1Wm-2 resolution) to test, over time, whether or not ongoing increases in atmospheric CO2 were causing consequent increases in downwelling radiation. I think that would be completely unachievable by any current (or, probably, conceivable) technology.

    But I am fighting a different battle: with skeptics who don’t believe in downwelling radiation AT ALL. Such people seem to have a visceral fear of it because they think that if downwelling LW IR is accepted as a reality, it would support the ‘CO2 causes warming’ mantra. I think their fears are completely unfounded and that their denials are actually impeding progress and making climate skepticism look ridiculous.

    So, I need to point out to such people the observational data showing substantial downwelling radiation – and for that purpose 1 significant digit of accuracy would be absolutely fine, let’s say 300Wm-2! Which explains my relaxed attitude over the accuracy of Trenberth’s figures just as your diffrerent perspective explains your valid concernsover them.

    I do understand from your earlier comment above that you are not one of those who deny the existence of downwelling radiation, and apologise for earlier assuming that you were. I am not so sure about other commentators here but presumably that at least puts to rest our previous diagreements?

  108. Bryan says:

    MostlyHarmless

    On page 28 of the CNR1 manual it states that there is no primary standard for pyrgeometers.

    Now this seems strange to somone who looks into this for the first time.
    The unit is the W/m2 so it should be easy to tie it into the international systems of units however it is not the case.

    It seems that it is impossible to cross check the calibration by using some other independent process that outcomes in Watts and metres squared.

    Looking further into it you find that you are tied into a circular reasoning loop .
    The devices are gauged against themselves and a black-body source.
    So if the theory is used to set the calibration you cannot use the instrument to verify the theory.

  109. AlecM says:

    PS Read the Kipp and Zonen pyrgeometer literature and they specifically point out that only net radiation is real. These people are Physicists no Climate Alchemists so they cover themselves.

    Just because an instrument outputs a power signal doesn’t mean you have to believe it.

  110. AlecM says, February 14, 2013 at 11:10 am

    AlexM, I agree with your final conclusion (that the CO2 warming matra is almost certainly a busted flush) but I profoundly disagree that back radiation is a fiction. Pyrgeometers (which is what this blog is about) measure it reasonably accurately, certainly to a very modest 1 significant digit, to be around 300Wm-2 (world wide mean value). If you deny such an obvious empiical fact you walk straight into the trap of the warmists. The observational facts are clear and your absurd claim devalues any other strong arguments you may bring to bear to support your commendable skeptical position.

    Actually, it is just arithmetic and sophistry at work here. You are absolutely right to point out that downward and upward radiation offset one another, mathematically speaking. And, in reality, it is the net flow in one direction or the other that defines the actual net energy transferred. So your sums work out correctly. But the existence of radiation, whether it is upwards, downwards, or sideways really cannot be denied, especially since radiating bodies have no concept of ‘up’, ‘down’, or ‘sideways’. :-)

  111. AlecM says:

    To David Socrates: 11.17 am.

    The argument is not about ‘back radiation’ nor the implied thermal impedance because that notional flux opposes the notional IR from the earth’s surface. It is irrelevant for self-absorbing GHGs.

    Their radiative energy to the surface is annihilated with no energy absorption. This is Maxwell’s Equations. Radiative Equilibrium Physics 101 all professional engineers and physicists are taught and should retain as part of their professionalism is the poor man’s way of explaining this, The net difference of S-B equations but these falsely imply two radiation streams when there is just one, the electromagnetic continuum.

    So ;’back radiation’ is of no consequence except for the non self-absorbed water vapour and trace gases which comprise the real 23 W/m^2 absorbed IR. This is why there can be no CO2-AGW at a first order level.

    As for pyrgeometers, sorry to harp on about this, but a temperature reading translated to a power reading as back radiation can be considered as a potential energy.

    Thus imagine a ball dropped from height H and unity coefficient of restitution. It bounces back to the same H so net energy transfer = zero. So it is with two opposing radiators.of equal temperature. The potential energy is very different from the net energy transfer. An emissivity = absorptivity <1 for one body is the same as <1 coefficient of restitution.

  112. michael hart says:

    I’ve pasted a quote below from the SHI cryogenics group at:
    http://www.shicryogenics.com/index.php?option=com_content&view=category&layout=blog&id=13&Itemid=62&lang=en

    “Keeping the James Webb Telescope cool will be a challenge, with a sunshade the size of a tennis court and a cooler system to chill it’s infra-red sensors to -232C (41K). MIRI operates at this temperature because infra-red radiation is heat. Any objects warmer than 15.5K in or around the instrument would give off an infra-red glow that could be detected by the instrument and interpreted as a light signal. Even infra-red radiation from the earth itself would ruin any experiments.”

    My question(s):
    If high-end IR detectors are supercooled to reduce detector radiation (as I have often been given to believe), then why is the same not possible in atmospheric measurements? Many lab instruments are supercooled.

    Is it a cost issue relating to the engineering required to prevent condensation etc?

  113. AlecM says:

    David Socrates 11.37 AM.

    ‘Back Radiation’ does not exist. It is easy to prove this by experiment. Have two pyrgeometers back to back in zero temperature gradient. The net signal = zero.

    Now take one away and the net signal jumps up to the potential power output to a sink at absolute zero of the emitter(s) in the field of view. Yet the initial signal was and remains zero. Therefore ‘back radiation’ does not exist as a separate entity in the EM continuum.

    The single instrument signal is the difference between the 360° zero net radiative flux and what is excluded by the shield behind the detector..

    In other words, you use a pyrometer to measure temperature not energy flux.

    Also, a pyrgeometer doesn’t work like they’re claimed to work. When measuring atmospheric temperature, the sensor plate equilibrates by cooling below the atmosphere temperature because of emission via the atmospheric window, until internal convection makes up the difference of the heat flow.

    This is why they now have thermistors to measure body temperatures, to attempt to linearise this internal conduction – the ‘Philipona equation’.

    This failure to understand how this instrument works has wasted 100s of man years of research in Climate Alchemy and is why they have totally failed predictively. My teachers of the past would have sacked me for such a failure. What we now have is people being rewarded for telling porkies, and 1000s of researchers being misled by these charlatans.

  114. AlecM says:

    Michael Hart 11.54 AM. A cooled bolometer is attractive except for the atmospheric window which means you always have bi-directional radiative heat transfer on non cloudy days.

    The only real way to solve the problem is to use two FTIRs back to back and subtract the signals but then the IPCC would see there can never be any CO2-AGW. and would can the project at source.

  115. Bryan says:

    David Socrates says

    “I am not so sure about other commentators here but presumably that at least puts to rest our previous diagreements?”

    Yes I agree
    I think your throttling idea is worth exploring.

    There seems to be much more energy circulating in the system than is supplied by our daily slug of solar energy.
    Much more latent heat contribution and the biosphere which the IPCC ignores and instead attributes everything to the greenhouse effect and the villain CO2..

    I do not think Climate science is normal science.
    I was alarmed when Climate-gate exposed very serious departures from normal science.
    There is a small leading group who think in terms of a ’cause’ rather than rational investigation.
    My blogging activity dates from post Climate-gate.
    I have trust in the vast majority of hard working scientists and engineers.
    I would not dream of critically commenting on their work in any area outside climate science.

  116. A C Osborn says:

    AlecM, THANKYOU.

    You have supplied the answer to my questions.

    I envisaged photon flows talked about by Climate Scientists like water, try making a Fire Engine 3″ diameter hose at full pressure flow wet with an apposing 1/2″ garden hose using mains pressure.

  117. thefordprefect says:

    Bryan says: February 14, 2013 at 11:20 am

    Looking further into it you find that you are tied into a circular reasoning loop .
    The devices are gauged against themselves and a black-body source.
    So if the theory is used to set the calibration you cannot use the instrument to verify the theory.

    ——————-
    Using transfer standards is a very common practice.
    I have used capacitance standards calibrated by government body to a measured value at a measured temperature.

    These are low drift components and can be used to calibrate other instruments.
    All calibration houses use transfer standards – there is not a long queue of engineers waiting to use the metre reference suit, the voltage cell, or the frequency reference chamber waiting to calibrate a dvm!

    So a non-portable black body reference is used to calibrate stable pyregeomters

    . These will have been proven stability and can then be used to calibrate other devices. some accuracy with ref to the standard BB will be lost.
    ========================================


    michael hart says: February 14, 2013 at 11:58 am
    My question(s):
    If high-end IR detectors are supercooled to reduce detector radiation (as I have often been given to believe), then why is the same not possible in atmospheric measurements? Many lab instruments are supercooled.

    Is it a cost issue relating to the engineering required to prevent condensation etc?

    Cooled thermal imaging cameras produce less noisy pictures than room temperature versions and will measure smaller temp differences (0.015C). The cost will be more, and the conveniance less (you’ll have to wait for the camera to cool (10 minutes), and the battery life less
    Most people are happy with a non cooled version for engineering purposes. But the small differential temperatures enable gas leaks to be detected and provide better human recognition definition.

    As you say somewhewre in the system there must be a condesation zone (even with insulation) I do not know how they handle this.

    e.g. http://www.flir.com/cs/apac/en/view/?id=55757

  118. AlecM says:

    A C Osborn: Climate Alchemy’s knowledge of physics is sorely lacking. You can’t blame them for this though because Planck never really completed his work.

    It’s because he was never happy with the idea of the photon. My view is that it does not exist except when a net Poynting Vector develops near a sink or a source of quantised energy.

    The idea of photon streams is ludicrous. Lots of physicists believe in a photon gas but you can’t buck Maxwell’s Equations.

  119. mkelly says:

    Tim Folkerts says:

    February 13, 2013 at 8:06 pm

    In this post you show that W/m^2 is the equivalent of T in Kelvins. Can I just add 273 K to 300 K and get a temperature in Kelvins higher than 300?

  120. Tim Folkerts says:

    AC says: “I envisaged photon flows talked about by Climate Scientists like water…
    That is one analogy, but it has serious limitations and errors when talking about photons. Photons can pass right through each other — water molecules can’t.

    AlecM says: “Lots of physicists believe in a photon gas but you can’t buck Maxwell’s Equations.
    Wave-particle duality has been experimentally and theoretically confirmed by a wide variety of experiments. You are living in the 1800′s, my friend, with your disbelief in photons. Einstein did buck Maxwell, expanding our knowledge of the universe and allowing us to understand the photoelectric effect (among MANY other readily observed phenomena).

  121. tchannon says:

    Okay folks. Spoke to Tallbloke yesterday, he’s been away to collect a winter affliction, still recovering, we wish him well. There is fun stuff coming so I will hold on more content. Got lots of content from me in due course.

    I managed to actually sleep again, it won’t last…

    Gradually we are entering early spring in England, days of low cloud, 1C night and day has switched to approaching 10C, breaks in cloud, a frightfully bright light showing at times.

    My spring reference, clump of snowdrops tight north side under a hazel has been showing white tips for near a month, still in limbo. A few elsewhere are just about out, also in limbo. Rhubarb is well through, idiot.

    Popped outside north side, pointed IR gun at ground, 7C, will be warming, at cloud -1C, a fairly blue patch with some cloud, -24C (it is full daytime), no surprises. This is not what it is designed to do, so what. Point at freezer contents -18, fridge ice box -10, radiator 60 and so on.

  122. tchannon says:

    Continuation from plot above as weather changed and now we start to see the truth.

    Plots below.
    Upper plot is still unclear on it’s real meaning, cloud is now broken so incoming solar is obvious but so far it is unclear whether the trace is of net, the balance, for that we need a clear night when it should start to read negative.

    Lower plot shows reduced sky temperature as the clouds broke even in sunshine. No surprise.

  123. AlecM says:

    T Channon: the IR gun will probably have filters so you measure the atmospheric window 8 – 24 microns eliminating most GHG emission!

    This is why you measure -24 °C for the blue sky, cloud at -1 °C should be for 1 km base level 5.5 K lapse rate below ground temperature, ~2.5 : too low.temperature, so it’s really measuring the atmospheric window part of the grey body cloud spectrum, no GHG emission!

  124. AlecM says:

    Tim Folkerts; 3.13. Don’t for one moment imagine I do not believe in wave particle duality. it’s just for that duality to exist there has to be a source or a sink for it to come or go.

    To think of streams of IR photons from an IR optical source either hitting home a sink of exactly the right energy or bouncing off such a sink which is full of energy from the inside or the outside is a recipe for the crazy thinking in Climate Alchemy!

    The reality is the EM continuum of opposing monochromatic waves with Poynting Vectors on which is superimposed thermal incoherence. The net energy transfer can vary locally depending in the Poynting Vector. On average though, the laws of standard optics apply.

    The real problem with Climate Alchemy has been its obsession with S-B instead of the Planck Irradiation Function which for a collimated beam is identical at any lambda to the Poynting Vector.

    The real data should be from back to back FTIRs so you have net PVs at any lambda. Then you see exactly the same data as the experiments show: 40% IR, 60% convection+evapo-transpiration. 1/3 rd the IR is absorbable, non self-absorbed trace gases and water vapour, no CO2 IR bands except minor stuff., 2/3rds is the atmospheric window.

    Hence the climate models exaggerate IR absorption plus atmospheric window by 6.85 times hence CO2-AGW and positive feedback is imaginary and offset the extra warming by cheating in the hind casting. no climate model can predict climate

  125. Tim Folkerts says:

    tchannon says: ” … Upper plot is still unclear on it’s real meaning … “

    No, it isn’t really that unclear. They say it is an instrument to measure solar irradiance and it behaves like an instrument to measure solar irradiance. It drops to zero at night; it rises to ~ 600 W/m^2 at noon on a sunny day which is about what you would expect; it is well below 600 W/m^2 at noon on cloudy days.

    “Lower plot shows reduced sky temperature as the clouds broke even in sunshine.
    No, it shows reduced irradiance. The drop of about 100 W/m^2 is due to the absence of clouds and their ability to “fill in the atmospheric window.” There is no direct way to determine the

    Look at MODTRAN results (http://forecast.uchicago.edu/Projects/modtran.html — a resource anyone in this duscussion should get familiar with)
    * Look up from 0 km for Mid-Latitude Winter — 207 W/m^2
    * now add cumulus clouds — 292 W/m^2
    (it is valuable also to look at the shape of the IR spectra).

    These are in the same ballpark as Chilbolton (presumable slightly higher temperatures at Chilbolton and perhaps different clouds than the model).

  126. AlecM says:

    Tim: MODTRAN creates the Planck irradiation Function which when integrated is the S-S equation.. To get net flux at any position, you subtract Down from Up.

    Only net flux can do thermochemical work.

  127. AlecM says:

    Sorry – S-B equation, not S-S.

  128. Tim Folkerts says:

    Alec,

    More specifically, MODTRAN creates the Planck irradiation Function which when integrated FOR A BLACK BODY is the S-B equation. Of course, the spectrum from the sky is not a BB.

    “Only net flux can do thermochemical work.
    I don’t think I would have said it exactly that way, but I’m not going to ague the wording. The “heat” = net flux is indeed important in the behavior of heat engines.

    But the fact that net flux is related to the ability to do work does NOT mean the individual flows do not exist. As an analogy, I might only get taxed on my net income, but that doesn’t negate the reality of gross income & expenses. The two opposed flows exist, but they “counteract” each other to produce the “net” effect.

    [Reply] Not forgetting the existence of the 4 times bigger flow sideways of course.

    There really are 459 W/m^2 of IR photons leaving a 300 K BB — independent of any temperature of any other object around.

  129. Roger Clague says:

    AlecM says:
    February 14, 2013 at 11:10 am

    Above cloud level thermalisation falls off so Kirchhoff’s Law of Radiation ceases to apply by TOA except for stratospheric emission.

    Please explain and support this statement.

    I argue that Kirchoff’s Law of Radiation does apply at TOA. That is for the surface together with the atmosphere, and not at the surface. Because at the TOA there is thermal equilibrium. The surface is not at thermal equilibrium. E.g. day/night and poles/equator.

  130. mkelly says:

    Tim Folkerts says:

    February 14, 2013 at 7:31 pm
    “There really are 459 W/m^2 of IR photons leaving a 300 K BB — independent of any temperature of any other object around.”

    So you are saying then that the surface of the earth can only emit what the sun deposits and is ” independent of any temperature of any object around” say CO2.

  131. wayne says:

    AlexM, thank you so very much for the clarity above, any additions would be hugely appreciated. ;)

    What is this of ‘self absorbing’ and ‘non-absorbing’? I don’t recognize the nomenclature off the top. Have anything to do with the lack of a permanent dipole? The linearity of the molecules?

    Is it the same as mentioned in this comment over at Judith’s site:

    Spartacusisfree | September 6, 2012 at 12:42 pm

    My Dear lolwot, there’s absolutely no evidence proving any CO2-AGW. There are ample data showing that by ~200 ppmV in dry air, the emissivity of CO2 levels off due to self absorption:
    These dry air data exactly replicate the experimental data of Hottell in the late 1940s used to design furnaces, replicated 30 years later by Leckner.. This explains the reduction of CO2 band IR at TOA.

    But what’s really interesting is the effect of humidity: by ~10% RH at ambient the emissivity change, therefore the absorptivity change of CO2 with change of concentration is zero. In other words, CO2-AGW is only possible for the most arid of deserts. This mixing effect has been completely ignored by the IPCC.

    However, the coup de grace for the GHG blanket is that IPCC modelling assumes ‘back radiation’ makes up what is supposed to be the same IR from the Earth’s surface as an isolated black body in a vacuum. ‘Back radiation’ does not exist: it’s a failure to understand it’s the artefact of of shielding radiation from the other direction which would normally annihilate all or some of IR a pyrometer receives.

    The logic forces only one conclusion, GHGs in self-absorption reduce the emissivity of the Earth’s surface in those bands and the GHE is caused by increased impedance for energy flow. the only atmospheric IR warming is from non-absorbing residual side-bands of water vapour. The GHE is fixed by the first ~1000 ppmv water vapour. Time for the ‘consensus’ to be put into the barrel marked ‘junk science’.

    Spartacusisfree | September 6, 2012 at 12:49 pm

    PS What I am developing is the real explanation of Miskolczi’s observations and the physics underlying his theory.

    Is that the same topic you are referring to? Why CO2 lines do not even appear and limited to Planck’s curve until the ~217 K level. That water vapor molecules are generally always saturated at all available energy levels per the local temperature and it is stimulated emissions there that are letting the bands in water vapor to have a free ride to space at all temperature levels?

    Any clarity in this realm sure would be appreciated.

    [mod WordPress for some reason clipped part of Spartacusisfree's comment I referenced above:

    "... off due to self absorption: http://notrickszone.com/2012/08/07/epic-warmist-fail-modtran-doubling-co2-will-do-nothing-to-increase-long-wave-radiation-from-sky/ ..."

    Maybe that can be pasted in? The whole reason for his logic was left out. -- not clear exactly where so here is the comment]

  132. wayne says:

    Sorry Alec, not Alex. My mistake.

  133. tchannon says:

    TF, I am very slow, their wording means little to me so I don’t trust it until I see it walk. Clipping at zero is a trick I have seen too often.

    If it is a net py., it will go negative at night. Read the text on the plot, says py. You say zero. See the problem?

    It is now dark here, clear sky and the truth is revealed. The upper trace is zero.

    The sky was hazed blue (rare to get properly clear here) at dusk, see sky photos, microwave shows a lot of water up there. The sky half py. is now as it was during the day reading lower than under cloud. The all sky “py.” is now shown as unclear on what it really is.

    It isn’t net py.
    It isn’t a half py.
    This suggests it is insolation, which is not py. as labelled. I do not know what it really is. (might try and figure out the actual instrument)

    No data on py. body temperature is given.

    (bit later) is now particularly clear, after rain, moon and starlit night. For the record now reading -33C on sky, 4C on concrete north side. (regardless of what it means, is writ down)

    I might script up gently grabbing the Chilbolton plots, which can be decoded to numbers if needed. There are a variety of things need investigating to figure out what actually happens, a matter of doing it and now Rog is back I can do more.

    Why doesn’t modtran provide accurate values?

  134. tjfolkerts says:

    tchannon, does “py.” mean “pyrgeometer”? If so, I would point out that the top graph is actually labeled “pyanometer” which (with the help of google) is used to measure solar energy (presumably ~ 0.1 – 4 um).

  135. tjfolkerts says:

    mkelly asks “So you are saying then that the surface of the earth can only emit what the sun deposits and is ” independent of any temperature of any object around” say CO2.

    No, I am not saying that at all!

    I am saying that if the surface of the earth happens to be 300 K (from whatever sources of energy it might have used to reach that temperature) (and happens to be a blackbody), then it would radiate 459 W/m^2 of IR photons. That energy could have come from the sun … or from DWIR or an electric heater or radioactive rocks or geysers or … (or any combination of these).

  136. tchannon says:

    Ok, I can’t read. Never heard of it either.

    Will still suffer the temperature problem. I’m considering on how important this is.

  137. suricat says:

    tchannon says: February 14, 2013 at 9:23 pm

    Touchy subject for instrumentation! The ‘py’ (instrument body temperature) alters the gain rate of ‘OP AMPS’ (operational amplifiers). The ‘commercial’ solution is to use a thermistor for temperature stability, but this solution gives low accuracy for a high production output of manufacture.

    For better accuracy a negative feedback ‘AMP’ (amplifier) is used within the ‘IC’ (integrated circuit [multiple OP-AMP IC in this case]) to give an ~absolute temperature correction, but each unit of production needs to be taken to its extremes of temperature to assess the ‘feedback factor’ needed for correction. Thus this latter process is more expensive and counter to a ‘high production/cost’ model.

    The +- 10% accuracy looks more like the ‘thermistor’ job than the +- 1% ‘OP-AMP’ calibrated job to me. Needless to say, a ‘thermopile’, or ‘thermocouple’, can only relate to ‘sensible heat’ and not a ‘radiative flux’, or any ‘latency’ process. I’m confused! :(

    Without a ‘circuit diagram’, or ‘schematic’, I can’t even begin to assess the product in question.

    I’ve not even ‘seen’ one. :)

    Best regards, Ray.

  138. Further to my comment of February 14, 2013 at 8:34 am where I listed 5 good reasons why pyrgeometers are real instruments, with the best ones probably accurate to 5%…

    REASON 6. On further research, the manufacturers of the Kipp & Zonen pyrgeometers quote an uncertainty on CGR-4 measurements of 3% for daily radiation totals and less than 7.5 W/m2 for individual measurements.

    For my purposes (establishing whether Trenberth’s world mean value of 333Wm-2 is correct even to one significant figure) a 10% accuracy is just great.

    As the (resolved) issue with Bryan shows, if you are looking for sub-1% accuracy, forget it.

  139. AlecM says: February 12, 2013 at 9:25 am
    AlecM says, February 14, 2013 at 1:24 pm
    AlecM says, February 14, 2013 at 11:10 am
    AlecM says, February 14, 2013 at 11:10 am
    AlecM says: February 14, 2013 at 11:42 am
    AlecM says: February 14, 2013 at 1:24 pm
    AlecM says: February 14, 2013 at 4:33 pm
    AlecM says: February 14, 2013 at 12:02 pm

    AlecM,

    This thread has developed away from a discussion about pyrgeometer instrumentation (we have probably flogged that to death!) into the much more general area of radiation physics.

    Sadly I note that you have not commented within my original TB blog article (from which this one on pyrgeometers was spawned)…

    “Atmospheric Thermal Enhancement Part I – The Great Debate Begins”

    Too late now because Part I is now more-or-less drawing to a close, with everyone waiting for the imminent Part II.

    But when Part II does get published it would be great if you would join in the debate. I am sure it is going to be about physics details and I think you have a lot of knowledge to contribute. You would be a good, and equally polite and measured, foil to Tim Folkerts (warmist) and to Roger Clague (skeptic). What we will need is some real experts.

    The only thing I would ask is that you bear in mind that not everyone reading your comments will understand all of your terminology. So please go easy on us, insofar as that is realistic given the inherent complexity of the subject.

  140. In the meanwhile, I offer the following analysis of the ‘back radiation’ controversy:

    1. AlecM is absolutely right to point out that measuring uni-directional radiation from one body to another (assuming one can do it!) doesn’t tell you anything useful about the net energy transfer between those two bodies. That can only be determined by measuring the unidirectional transfers in both directions and then subtracting one from the other. At that level of argument, I don’t think any reasonable person with any physics knowledge would disagree with his logic.

    2. In the case of two bodies radiating at exactly the same level towards one another, there is obviously no net energy transfer between them. So nobody would disagree with that either.

    3. In the case of the earth’s surface-atmosphere interface, the net radiation transfer is (according to Trenberth’s figures) a tiny 23Wm-2. People might argue with Trenberth’s actual figures (sigh!) but very few people would argue against the notion that the net value is quite small – i.e. that it is tens rather than hundreds of watts per square metre.

    4. For a warmist, that smallish figure is OK because their calculations are already based on that kind of value. It is therefore within their comfort zone.

    5. For the skeptic, the smallish figure is also OK because it looks incredibly small compared with the other incoming energy flows to the atmosphere totalling 175Wm-2.

    6. What is fiercely controversial is the depiction in the Trenberth and other diagrams, of the two large uni-directional flows between surface and atmosphere (356Wm-2 up; 333Wm-2 down) rather than (as is done in some later diagrams) just the small net transfer figure of 23Wm-2 up.

    7. Why should this be such a controversial problem when it is only really an artefact of a diagram, with everyone actually agreeing about the net energy transfer anyway? I believe the answer is psychological: skeptics are concerned that putting in the two huge uni-directional figures lends false credibility to the notion that radiation is boosting the temperature of the atmosphere; whilst warmists are concerned that to leave out the uni-directional figures lends false credibility to the notion that radiation has little or nothing to do with boosting its temperature. So the bottom line is that everyone is getting emotional about…a diagram!

    8. In my blog article, I have tried to demonstrate why skeptics should not fear the depiction in the diagram of large upwelling and large downwelling values. And the key I now realise (but I did not explicitly mention it there), is AlexM’s point that uni-directional radiation does not do work.

    9. By showing the two very high uni-directional flow values, the Trenberth diagram has the virtue of demonstrating that the atmosphere is at an elevated temperature because of the huge fund of Kinetic Energy stored within it. One of the consequences of that elevated temperature is the huge circulation of ‘virtual energy’ (for want of a better term!) of 333Wm-2 that appears to be going round and round in a circle between surface and atmosphere doing no work.

    10. So the bottom line on all this is that a diagram is a diagram. Nobody should be afraid of those uni-directional flow figures (even if, as AlecM maintains, they are in fact virtual: physics has plenty of useful virtual concepts!) Skeptics should rejoice because those two large values actually make the psychological point perfectly that the atmosphere is warmed by a trapped FUND of KE and not by radiation.

    11. In my blog article I used the same concept when discussing the Bulk of the Atmosphere where there is an ever-present ‘fog’ of radiation. This buzzes around in all directions being continually absorbed and emitted. But that radiation is a consequence of the levels of KE at the various elevations and not their cause. To deny that this ‘net zero’ radiation exists (whether, from a physicist’s point of view, virtually or actually) will not do the skeptical cause any good.

  141. AlecM says:

    Tim Folkerts 7.31 pm: ’There really are 459 W/m^2 of IR photons leaving a 300 K BB — independent of any temperature of any other object around.’

    Only for an isolated body in a vacuum radiating to the cosmic microwave background.

    In all other cases, the net flux is determined by the vector sum of all the Poynting Vectors. This means you can have bidirectional radiative flux in and out of the atmospheric window coupled to convection, evapo-transpiration and conduction. You get all the parameters from 4 rate equations relating internal kinetic energy via the activated intermediate state to the EM world or to molecules.

    Think of the net PV formation as a handshake routine like when you put your PIN into a cash machine. Until that moment there is no value = energy transaction even though you are radiating potential wealth!

    Roger Clague: 8.49 PM.

    There is no direct thermalisation – quantum exclusion and local thermodynamic equilibrium. Will Happer warned the IPCC of this mistake on 1993.

    Any surface ‘photon’ is absorbed and at the same time an already activated GHG ejects the same energy. So the atmosphere is full of peripatetic photons finding a heterogeneous site to thermalise.

    Above cloud level this becomes less probable so increasing those photons and thermsl photons that go to lower temperature so are not in LTE spill over to space. Therefore Kirchhoff’s law of radiation cannot apply at TOA because there is no direct thermalisation.

    Wayne: 9.02 pm. Self-absorption is standard physics completely missed by Climate Alchemy. Also by another quirk of physics, a self-absorbed GHG band appears at the BB level to an atmospheric radiometer but at the self-absorbed level [half BB level for CO2] by a satellite radiometer – it’s a very simple explanation, purely statistical..

    http://www.thespectroscopynet.eu/?Physical_Background:Atomic_Emission_Lines_Shapes:Selfabsorbed_lines

    13 mistakes in Climate Alchemy and counting – I’m just a humble engineer who doesn’t believe any bullshit except where there is absolute experimental proof. Standard radiative equilibrium physics means the thermal 15 micron CO2 band is at the BB level so Poynting’s Theorem means it annihilates the same IR emission from the Earth’s surface. Lapse rate keeps the atmosphere at the same temperature as the surface.

    So, that plus no direct thermalisation means there can never be any CO2-AGW or indeed any GHG-AGW where the GHG is in self-absorption.

    As for ‘back radiation’ never detected, it is an assumption based on the belief that when you scale temperature to potential flux, that potential flux is real. It isn’t.

  142. AlecM says:

    Correction: ‘Standard radiative equilibrium physics means the thermal 15 micron CO2 band is at the BB level so Poynting’s Theorem means it annihilates the same IR emission from the Earth’s surface.’ This implies that the BB level for the thermal GHG emission is the artefact caused by the optical heterogeneity of the surface – there is no self-absorption for thermal photons near that surface. Hence the surface PVs are annihilated at source even though their amplitude is above the true self-absorbed absorptivity/emissivity in the bulk.

    Further argument gets into heavy statistical thermodynamics.

  143. mkelly says:

    tjfolkerts says:

    February 14, 2013 at 11:48 pm

    mkelly asks “So you are saying then that the surface of the earth can only emit what the sun deposits and is ” independent of any temperature of any object around” say CO2.”

    No, I am not saying that at all!

    I am saying that if the surface of the earth happens to be 300 K (from whatever sources of energy it might have used to reach that temperature) (and happens to be a blackbody), then it would radiate 459 W/m^2 of IR photons. That energy could have come from the sun … or from DWIR or an electric heater or radioactive rocks or geysers or … (or any combination of these).

    So you are saying that the earths surface is not “independent”? Either it is independent or it is not. Please pick one.

  144. tchannon says:

    David

    It seems that I have not made myself clear. A split whole instrument cannot reasonably measure inbound from the sky.

    I will try a tale.

    Let’s take the earth with full cloud cover and assume there is zero net energy flow.

    We put an instrument at the equator and wait for it to settle. Let’s say it reads 400.

    Now move it to say 70 north. You can have say 200 or 400, which do you want?

    Why so? Because the reading is a pure fabrication, literally dependent on the instrument body temperature. There is zero flux, if you set the answer computation temperature to the same as at the equator you get 400. The instrument is inventing a flux value and that is body temperature power four.

    If you read the manual or the docs thefordprefect indicated you will see skating around this elephant.

    I mentioned earlier there is no advice or practice on matching actual ground temperature. This is not air temperature and is not soil temperature.

    This matters because this temperature is the assumed ground radiation temperature.

    The AGW claim is about outbound coming back as inbound, the mid point of a split instrument, the balance, is critical to the argument.

    Now can someone please either confirm or not what I am saying.

  145. A C Osborn says:

    Tim, did you nip down to the equator to try it out? /humour

  146. Tim,

    I really don’t follow you. The pyrgeometer at Chilbolton appears to be working fine and is giving a consistent reading in the right ballpark. You keep putting up screen shots to show this.

    There is “no advice or practice on matching actual ground temperature” in the manual because there is no need to provide any. You appear to have misunderstood how an advanced professional pyrgeometer works. It is temperature compensated, as its specifications tell you. Are you seriously suggesting that all over the world professional meteorological organisations like Chilbolton are being fooled by a heap of junk costing thousands of pounds?

    There IS a quite separate argument being advanced by some in this thread that there is no sense in measuring DWLR without simultaneously measuring UWLR because it is only the difference between the two that gives you a figure for the net real energy transfer, and that DWLR and UWLR are ‘virtual’ rather than ‘real’ radiation fluxes. Fine, I have some sympathy from a physics theory point of view. But that’s just an interesting philosophical discussion. Fact is, people get a consistent reading from pyrgeometers and the readings have clearly got more and more accurate over the years as the sophistication of the devices has increased.

  147. Tim Folkerts says:

    mkelly asks: “So you are saying that the earths surface is not “independent”? Either it is independent or it is not. Please pick one.
    Independent of what? I don’t understand your questions.

  148. Tim Folkerts says:

    tchannon says: “Let’s take the earth with full cloud cover and assume there is zero net energy flow.

    I’m not sure what you are proposing. Are you saying the entire earth has could cover (or perhpas only particular spot)? Are you saying that there is no net energy flow between surface & clouds (or between some other pair of locations)?

    ” … This matters because this temperature is the assumed ground radiation temperature.
    If I understand your concern properly (which quite possibly I do not), this is basically the same challenge as you have measuring temperature with a thermocouple. The actual signal from the device depends on the “reference temperature” (the cold junction for the thermocouple; the body temperature for the pyrgeometer). I don’t know ANY of the details about how the py. is built, but I would like to think that the engineers took into account the fact that the surface temperature varies!

  149. AlecM says:

    mkelly 3.04 pm: ‘I am saying that if the surface of the earth happens to be 300 K (from whatever sources of energy it might have used to reach that temperature) (and happens to be a blackbody), then it would radiate 459 W/m^2 of IR photons. That energy could have come from the sun … or from DWIR or an electric heater or radioactive rocks or geysers or … (or any combination of these).

    This is wrong. If the Earth is at 300 K, the static local atmosphere is at 300 K,and there is no water to evaporate, the only heat transfer that can occur is non self-absorbed GHG emission that can be accepted by the atmosphere plus the atmospheric window to space.

    All other heat transfer is switched off. Put in 160 W/m^2 from the sun and you upset that equilibrium. The bottom lone is that 300 K radiative heat transmission at its full rate is only achievable if the Earth were isolated in a vacuum.

    Sorry, but this fixation with temperature is ludicrous. I spent a very long time measuring these things in industry and for steel off a rolling mill, to get radiation to exceed natural convection needs >100 °C. For Aluminium it’s > 300°C.

    The Earth’s surface in still air loses very little heat except to space via the AW.

    Read up a good heat transmission handbook like the article by Hottel in Perry’s Chemical Engineering Handbook.

  150. AlecM says:

    David Socrates: 4.02 pm.

    A pyrgeometer reading is the potential energy flux the lower atmosphere could emit to a sink at absolute zero, it is the pyrometric temperature converted by S-B into that potential power

    The real flux could be zero.

    This is the biggest mass delusion in scientific history and has wasted 100s of man years of work in a wild goose chase. Only net flux is real……

    In no other subject except Climate Alchemy are students taught false physics as part of their course. This is a serious slur on academic science despite meteorology teaching it for 60 years…..

  151. wayne says:

    AlecM, thanks much. I’ll take the time to progam those equations in to get a better understanding of that effect.

  152. mkelly says:

    AlecM says:

    February 15, 2013 at 4:33 pm

    Thanks for the info Alec but Mr. Folkerts is the person saying that not me.

  153. mkelly says:

    Tim Folkerts says:

    February 15, 2013 at 4:18 pm

    mkelly asks: “So you are saying that the earths surface is not “independent”? Either it is independent or it is not. Please pick one.
    Independent of what? I don’t understand your questions.
    Tim Folkerts says:

    February 14, 2013 at 7:31 pm
    “There really are 459 W/m^2 of IR photons leaving a 300 K BB — independent of any temperature of any other object around.”

    You used the word “independent”. I am trying to figure out what you mean and how it applies to the surface of the earth. Please read your own words. “independent of any other object around” said Mr. Folkerts.

  154. Tim Folkerts says:

    Alec emphatically states: “Only net flux is real……”

    There is real radiation pressure.
    http://scienceworld.wolfram.com/physics/RadiationPressure.html or http://en.wikipedia.org/wiki/Radiation_pressure

    There is real radiation energy density.
    See for example http://en.wikipedia.org/wiki/Planck%27s_law or http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/raddens.html

    Both of these exist in regions where the NET flux is zero. Neither of this could exist if only “net flux” was “real”.

    I would agree that only net flux matters for a heat engine, but that is not the same as saying that only net flux matters for everything!

  155. Tim Folkerts says:

    mkelly,

    Whether on not the “surface is independent” depends on what property of the surface you might be interested in. Certain properties or dependent on some factors; other properties are dependent on other factors. Your question was (and still is) ambiguous.

    *******************************************************************************
    The thermal radiation leaving a surface depends only on the temperature and emissivity of that surface, and thus is independent of other factors like humidity of the air, sun shining on the surface, CO2 radiating down to the surface, etc.

    Once I know the temperature and the emissivity, that is good enough. Calculating the expected temperature is a completely different question. (And speak of the devil … )

    The temperature of a surface depends on many factors, including sunlight shining on the surface, CO2 radiating, how warm it was 2 minutes ago, etc.

    **********************************************************************************

    Since I had postulated a fixed temperature (“a 300 K BB”), then this question is simply about radiation, not about any actual temperature of any specific part of the earth’s surface.

  156. wayne says:

    ” this fixation with temperature is ludicrous “

    Boy, I could not agree more Alec. This is what causes some imaginations to go wild!

    Radiations are waves, Feynman understood this so very well, Susskind understands it. Waves combine, merge, morph, affect other waves at all frequencies, and change the local e/m field at every point in space, like complex wave patterns in the reflections in a swimming pool, that’s the way Feynman worded it. And it is the resultant combined e/m field, it’s incredibly complex wave patterns, within the local space continuum, that affects the actual transfer of energy and what pyrgeometers can “see” and record and what frequencies manifest themselves and where they are manifested. These are intensities and the probabilities (the normalized sum intensities squared) that determine whether there is even a “photon” of a certain frequency therefore carrying a quanta of energy existing at each and every point in space and time, if so there can be an absorption matching the matter energy levels at that point. Like waves in exact opposition they cancel themselves, no transfer of energy occurs at all in that case… follow the Principle of Least Action that all, and I mean all, of physics is built upon. (but you will have to delve a bit into the Lagrangians, the Hamiltonians, the actual physics that underlie all we are speaking of here in essence but seem unable to get down to the nitty-gritty of it all)

    I can see you and I are parallel but the words are a bit different, one an engineering view, the other a physics view, but in all essence they are the same. “Back-radiation”, except for being a negative term in some equations, has no foot in reality.

    Max(TM): yes, you can view it as “negative energy”, mathematically, as vectors, but your mention of 63 W/m² should have been closer to 333 W/m². ;)

  157. tchannon says:

    The dispute over pyrgeometer temperature dependence is open, no actual answer so far.

    Keep this in mind.

    I’ve been trawling, lot of details have turned up, including admitted errors from sunshine and dark sky (something like +25W and -15W) and transient effects.

    A surprise was discovering a totally different instrument design which implemented ideas I have had on how to measure IR for a different application. This design was done for US DoE, would be relatively very expensive and looks dead, last web update 2006. Must have been through serious stuff and mentions Davos.
    Uses a detector, mechnaical chopper, black body and mirror. This kind of detector responds to change. A classic design is chopper with reference(s) switched in. Synchronous signal decode can then be done. (used in some IR gas analysers I have worked on, how you get signals relative to a reference)
    http://www.yesinc.com/products/data/tir570/index.html
    This points to cost as the reason for the simple devices. Usually the case, money wins.

    I wonder if they would talk and spill some beans?

  158. Tim,

    You say: The dispute over pyrgeometer temperature dependence is open, no actual answer so far.

    What answer are you seeking? Both Tim Folkerts and I have separately suggested to you that it is unlikely that an expensive commercial product like the Kipp & Zonen CPR4 intended for use by professional organisations would be so badly designed that it could not perform over a wide range of temperatures.

    On further investigation I find on page 26 of the CGR 4 manual that the temperature sensitivity is less than 1% between -20degC and + 50degC.

  159. This discussion has moved off-topic, as was feared. Those who question how radiometers (generic term for all radiation-measuring devices) work whether they actually measure what is claimed for them, seem not to question the role and function of satellite-borne detectors. They of course work in the same way(s) as terrestrial high-accuracy instruments. The instruments being discussed here are not such high-precision instruments as used in measuring LWIR and plotting spectra – they cannot be, they cannot resolve narrow frequency bands at all They can’t resolve any frequency bands – they integrate incident radiation and record a single value. They’re designed for use in met. stations, not research.

  160. tchannon says:

    That is the temperature specification of the sensitivity (gain).

    So far as I know there is a thermopile which is just series connected thermocouples and associated with that is a “compensation” circuit, manufacturers are coy on the details.

    Since I notice the temperature characteristic is strange whereas thermocouples have no mysterious narrow temperature range but are inherently non-linear and also the device has a surprisingly high output resistance, thermocouples are metal wires, I assume this is a fiddle factor non-linearity compensator involving resistors and possibly thermistors. That would explain the narrow range and curves. (recommended load is >=1M ohm)

    The only other thing in there is a body temperature sensor.

    Both sensors are fed via wires to the outside world.

    The instrument manufacturer has nothing else to do with things.

    External to the device the user has to compute a useful output. This is where the trouble appears.

    I expect the manufacturer will wash their hands of foolish users but do not so far as I have seen made suggestions or recommendations on how to try and fix this problem.

    This is likely to involve one or more external temperatures and perhaps computation producing a good estimate of the true ground temperature for this specific application and location.

    1. thermopile voltage (probably in uV)
    2. device body temperature as PTC resistance or whatever
    3. estimate true ground temperature
    4. device sensitivity calibration

    Now compute the flux value using all four.

    Nowhere I have seen is this mentioned.

    In some cases there is also a temperature sensor on the dome.

    The highest error figure in sunshine I have seen is 25W and for cold sky 12W

    Given all the temperatures this can largely be compensated.

    I am still saying I don’t know.

  161. wayne says:

    This discussion has moved off-topic, as was feared. Those who question how radiometers (generic term for all radiation-measuring devices) work whether they actually measure what is claimed for them, seem not to question the role and function of satellite-borne detectors.

    MostlyHarmless, I don’t see why you think this has move off topic. I think most here realize these are bolometric type devices, not operating on a per line or band basis, just a single averaged reading assuming a joule, no matter of its frequency, is going to have the same effect on the electronic sensor and circuit as from any other frequency.

    But satellite sensors are different in one big aspect, they all point downward upon a warm Earth, an energy source, and are in a near absolute zero environment devoid of little e/m field from any other directions, and then it seems close to reasonable that you can simply use the radiation that causes temperature that through electronics gives a voltage reading converted to flux that might then using the reverse Stefan-Boltzmann relation with an assumed emissivity to produce a brightness temperature. Satellite sensors never read “back-radiation”.

    But that is not what pyrgeometers used on the surface do so simply. They cannot just assume near ambient 0 K and must differential their readings with a measured radiation-to-temperature differential or offset that the difference is then sensed as a voltage change to imply flux. Then they might also use an assumed emissivity and the reverse of the Stefan-Boltzmann relation to generate a brightness temperature round trip.

    The real question comes, and that lies under this post, what ARE they measuring when turned backwards away from an energy source and pointed at a set of gases at temperatures much lower that the base ambient temperature of the device itself?

    Some see that as proof of “back-radiation”, it is making the sensor warm with it’s photons, just not quite as warm as pointing it down at the real energy source.

    Some see it that the sensor would be at the ambient temperature reading, the full flux from the energy source, except now it is pointing at something cooler and part of that energy (therefore temperature) of the ambient sensor can leave the sensor cooling it and that is what is being measured, the decrease from ambient flux, the energy not what is being received but that energy that is subtracting, a loss of warmth, not from “back-radiation”. These see no such thing exists called “back-radiation”. They see the first way to view this as a mathematical trick to imply something real that isn’t.

    So what do you think this device is measuring, in reverse mode pointing away from an energy source? Do you see photons flowing backwards into the device being absorbed and setting the sensor’s temperature above near 0 K, or, do you just see that not so many photons or e/m waves are leaving the already warm device that is in reality at the local ambient temperature?

    I think this post is right on topic. To me the “back-radiation” is mathematically equivalent but has no reality bound to it, I have the latter view, being just a negative term in the math used to compute a deviance in warm to cool radiation according to temperature differences between the two by the so misused Stefan-Boltzmann equation.

  162. AlecM says:

    Tim Folkerts 7.24 pm.

    I agree there is a radiation pressure but you can only measure the pressure by applying a force in the opposite direction. That pressure can be from the inertia of a spacecraft for example.

    Therefore it is a net effect which acts by an opposing Poynting Vector except this is from the equilibrium temperature of the sink. The question then is ‘Is there radiation pressure when the object sensing the pressure is at the same temperature as the source of the radiation?’.

    This is a key question. My suggestion is that when the PVs annihilate there can be no radiation pressure. Miskolczi thinks the GHE is work done by radiation pressure. He may be right!

  163. Tchannon says: February 16, 2013 at 1:36 am

    All your questions answered here.

    http://s.campbellsci.com/documents/us/manuals/nr01.pdf

    This is not the best sensor but seems to give 10% accuracy

    This has same correction formulas
    http://www.kippzonen.com/?download/35132/CGR+4+Pyrgeometer+-+Instruction+sheet+(EN+D+F+ES).aspx

    This shows errors expected and more
    http://www.kippzonen.com/?download/38192/CGR+4+Pyrgeometer+-+Manual.aspx

  164. Bryan says:

    MostlyHarmless says

    “Those who question how radiometers (generic term for all radiation-measuring devices) work whether they actually measure what is claimed for them, seem not to question the role and function of satellite-borne detectors.”

    Bolometers and Thermopiles are based on different thermal effects.
    Bolometers are thought to be reliable.
    Pyrgeometers based on the thermopiles have never been reliable .
    Since their introduction in 1950 various manufacturers have claimed to have produced a reliable device.
    In use the device consistently fails.

    In 2002 at Davos a user group set themselves the task of at least getting the various devices to read the same when pointed at the same sky.
    To do this they had to depart from the manufactures calibration equation which did not please the manufacturers.

    The users admit that there is a circular logic flaw in their operation.
    They can only be calibrated against another Pyrgeometer and black body theory.
    So the obliviously cannot be used to verify black body theory.

    In 2006 this latest hope was dashed as the instruments were reported to still be unsatisfactory.
    It would be wise therefore to wait for a suitable period of time before relying on the manufacturers persistently optimistic claims.
    This is most recent test I can find.

    It would be interesting to follow the suggestion of MostlyHarmless and put a Prygeometer in a satellite.
    No back radiation problem .
    It could be tested against bolometer sensor technology

  165. Is it necessary to be able to measure LWIR to verify SB? No, of course not. SB was established before any direct measurement of radiation was possible. Verification was by measuring temperatures, and comparing them with what the SB function predicted. Pyrgeometers measure temperature – nothing else, the result of heating produced by incident LWIR. That they measure upward flux from the ground is verified by measuring the ground temperature. When pointed up they measure something which indicates a source warmer than the instrument and its surroundings. Observation trumps off-beat theory every time.

    There’s no net transfer of heat energy via radiation between two bodies at the same temperature. Is there an exchange of heat energy between them? Of course – remove one and the remaining body cools down. Substitute a colder body for one of the original bodies and it warms up as the other cools down at a slower rate due to radiation from the colder body. Radiation doesn’t just appear or disappear at the whim of an hypothesis.

  166. A C Osborn says:

    MostlyHarmless says:
    February 16, 2013 at 11:18 am There’s no net transfer of heat energy via radiation between two bodies at the same temperature. Is there an exchange of heat energy between them? Of course – remove one and the remaining body cools down. Substitute a colder body for one of the original bodies and it warms up as the other cools down at a slower rate due to radiation from the colder body. Radiation doesn’t just appear or disappear at the whim of an hypothesis.

    Do not remove one body and they both cool down unless the only direction radiation can flow is between them, which is not what the atmosphere is about.
    So you are saying that Radiation cannot cancel or redirect Radiation?

  167. http://lasp.colorado.edu/sorce/data/tsi_data.htm
    On-orbit instrument characterization is an on-going effort, as the TIM team regularly tracks instrument degradation and calibrates the instrument servo system on-orbit, periodically updating the data processing system with new calibration values. Only minor corrections are anticipated at this phase in the SORCE/TIM mission. To date the TIM is proving very stable with usage and solar exposure, and long-term relative uncertainties are estimated to be less than 0.014 W/m2/yr (10 ppm/yr). Present absolute accuracy is estimated to be 0.48 W/m^2 (350 ppm), largely determined by the agreement between all four TIM radiometers. The 4.5 W/m^2 by which the TIM reads lower than prior instruments has been resolved as being largely due to internal instrument scatter in those prior instruments causing erroneously high readings (see Kopp & Lean, GRL, 38, L01706, 2011).

    http://lasp.colorado.edu/sorce/instruments/tim/tim_concept_op.htm
    The basic theory of ESR detectors is based on the measurement of electrical power to maintain constant detector temperature as incident radiation is modulated. Two identical sensors, one active and one used as a thermal reference, are housed in the same environment and maintained at the same temperature. The sensors have a very high and accurately-known absorptance in order to efficiently collect incident radiation, so that nearly all photon energy incident on the detector is converted into heat. A constant amount of Joule heat is supplied to the reference sensor by a resistive heater circuit, elevating this reference sensor to some temperature. The active sensor is actively driven to this same temperature by a servo system that determines the electrical power necessary to heat it via its resistive heater. This thermally balances the two sensors at the reference sensor’s temperture, and requires similar electrical heater power to each sensor in the absence of any incident light. When radiation is then allowed to fall on the active sensor, such as when that sensor’s shutter opens, a corresponding amount of electrical heat to that sensor must be reduced in order to maintain constant temperature. This reduction in electrical heat to the active sensor is equivalent to, and effectively “substituted” by, the radiant energy incident upon it. By knowing this electrical heating to a high accuracy, the incident radiation is measured to similarly high accuracy.

    some calibration stuff here:
    http://glory.giss.nasa.gov/tim/
    The calibrator is at liquid helium temps. it is a blackbody absorber, it and the tim device are in a vacuum, the calibration power is at expected solar levels.
    The calibration radiometer is basically the same as the satellite TIM – a radiation absorbing cone which is held at constant temperature the needed power is then related to the energy from the incoming solar irradiance.
    With TIM you are not expecting a wide variance of power levels to measure. TIM operates in a vacuum. So all tuning can be to a nominal level giving phenominal accuracy. TIM and the calibrator are not cheap so unlikely to be used other than on satellites (currently).

  168. We are simply going round in circles now.

    1. You can’t have a sensible argument about whether an instrument is accurate or not without defining needed accuracy. Also, Bryan’s historical trail over how inaccurate pyrgeometers were in 2002 is interesting but meaningless in terms of where we are now in 2013.

    2. Bryan and I had a misunderstanding (now resolved). I was happy with ~10% measurement error, so that the device could be used to prove or disprove empirically that Trenberth’s 333Wm-2 figure for DWLR was in the right ball park. Bryan wanted a much smaller measurement error, a fraction of 1%, so that he could use the device to show whether or not, over time, an increase in atmospheric CO2 does or does not cause a temperature increase. (Presumably Brian was prepared to wait 50 or more years to check that out, but, hey, his accuracy requirement was in itself perfectly reasonable, just different from what I needed.)

    3. The likely reality (denied still by many here without any kind of proof) is that the best-of-breed Kipp & Zonen CGR4 pyrgeometer has around 5% accuracy. If so, it happens to be good for my purposes but not for Bryan’s. So we have resolved our original difficulty.

    4. In fact Bryan and I are kindred souls: we both believe that LWIR is real and therefore, in principle, measurable.

    5. So the next onslaught comes from Sophists Anonymous, several people who believe that uni-directional radiation isn’t real. It’s just an imaginary artefact. They say that if two bodies at two different temperatures are radiating towards one another, then…er…they aren’t actually radiating towards one another – because uni-directional radiation doesn’t exist. But, nevertheless, if you subtract the radiative power that body A isn’tradiating towards body B from the radiative power that body B isn’t radiating towards body A, the difference is a real radiating power which transports real energy from one body to the other.

    All fine fun for armchair handwaving. But is it a debate that is going to enhance the skeptical position on climate change and bowl over the warmists? I think not.

  169. Bryan says:

    MostlyHarmless

    “Pyrgeometers measure temperature – nothing else, the result of heating produced by incident LWIR. with what the SB function predicted. ”

    Did you know that there is more radiation leaving the pyrgeometer than entering it via LWIR?
    Did you know that the second law explicitly says colder objects to not heat warmer objects ?

    If not read through the thread where these things were discussed earlier.

  170. tchannon says:

    Observation

    I recently was surprised to learn why paint peels yet obvious in hindsight. (note: not the only reason)

    Vapour pressure. Humidity difference when moisture in under the coating and lower outside.

    Talking of pressure a sharply critical problem of causal comes to mind where radiation pressure has been a claimed reason for effect, with many large names declaring “is so”. Can’t all be correct.

    Stuff we are dealing with here is very hard.

    My point here is demonstrating an instance of struggle to get a correct solution, not so much the actual answer. (telling is won’t work in hard vacuum)

    http://math.ucr.edu/home/baez/physics/General/LightMill/light-mill.html


    Image credit timeline. wikipedia here

  171. Bryan says:

    David Socrates says

    “Also, Bryan’s historical trail over how inaccurate pyrgeometers were in 2002 is interesting but meaningless in terms of where we are now in 2013.”

    David why do you continue to ignore the 2006 paper that showed serious inaccuracies?
    There has been no new developments since then that I’m aware of.
    Perhaps you have some new information?

    Also another source of error comes in when inaccurate emissivity values are introduced.
    Another source of error comes in when the atmospheres IR active gases are treated as black or grey bodies since they do not emit a full Planck spectrum.

    If the actual radiative flux is 300W/m2 say and defective theory calibration equation says its 400W/m2 then the newly calibrated instrument will have these inaccuracies built in.

    There is a large body of informed opinion saying that the quoted values of atmospheric radiative flux are too high.

    As AlecM says
    “Read up a good heat transmission handbook like the article by Hottel in Perry’s Chemical Engineering Handbook.

    Cementafriend makes the same point.

    The heat transfer expert Schack also says that the radiative effects of CO2 must be considered at furnace temperatures but at atmospheric temperatures are negligible.

    Industrial Heat Transfer: Alfred Schack, I. Gutman: 9780412079801 …

  172. tchannon says:

    thefordprefect, yes the concept of matching power is widely used (including by me many times over the years).

    The reason for doing this is not obvious to outsiders but whether a complete explanation is needed, up to people to ask.

    Snag with satellites is no-one can go look, nor bring it back later to see what it now does. Are always confounding things. Tend also to suffer from single point, there is only one when many are needed.

    With TIM I have never found a specific hard declaration of what it does. The only actual claims seem very vague (that basic measures 95% is not endearing). I also subscribe to the view it is looking through a fog.

  173. Steven Mosher says:

    ” But the whole point of my article was to show that the two-way enhanced radiation flow is a consequencenot a cause of the enhanced KE (read elevated temperature) of the atmosphere and that skeptics shouldn’t shy away from it but should take it on board to move the debate forward armed with the knowledge that they can do so from a position of strength, not weakness.”

    Precisely David.

  174. tchannon says:

    Pyrgeometer threads, don’t know if anyone is watching the threads, or for that matter is interested.

    I’ve been grabbing data from Chilbolton since February, missed one day.

    I’ve now pretty much working code to extract numbers from the line plots.

    An irritation is the plots are for 23 hours a day, last hour is missing, now confirmed by cross checking sun radiation against sunrise/set obtained from Solex. Couldn’t be certain how the timescale was out hence needed a definite time and duration.

    I think it is about 2.5 minutes per point, embarrassingly fine resolution. Going to be fun though trying to calibrate. Humidity for example never goes full scale 100%
    Could compute RH etc. if we wanted.

    The weather has moved on, frost, cold, sun, rain, cloud, Some additional data from elsewhere has been indicated if needed.

    Lot of stuff now for anyone wanting to explore weather. The original objective pyrgeometers and what gives is still there. Still pretty obvious it is essentially a cloud detector.

    I haven’t coded up doing all the file handling, extracting from the archives, hundreds of files. Bit by bit things get done.

    Any suggestions or ideas?

  175. Stephen Wilde says:

    Has no one registered the point that the clear sky reading is lower as compared to the cloud reading simply because the lower reflectivity of clear air causes the pyrgeometer to measure temperature at a higher, colder location ?

  176. Bryan says:

    Two years ago I looked into the uncertainty (or errors) associated with this instrument.

    http://www.webpages.uidaho.edu/~vonw/pubs/TownEtAl_2005.pdf

    Here is a fairly recent report based on field measurements in the Antarctic.

    It compares readings taken by an Interferometer and a Pyrgeometer.

    On page 4237 they quote the expected pyrgeometer uncertainty as being 8W/m2
    The readings taken were in the 100W/m2 range so a relative error of 8% was expected.

    On page 4239 the Pyrgeometer was consistently reading about double the comparative readings of the Interferometer.

    I have much more faith in the physics of an Interferometer than that of the Pyrgeometer and supports my feeling that while ‘backradiation’ exists, its magnitude is greatly overstated.

    The Pyrgeometer does not produce a direct reading of LWIR instead it produces an INFERRED value.
    The only direct measurement is the heat flow (in this case outward from the instrument).
    The temperature of the instrument is used to get SB value for upward flux and a calculation made and displayed.
    Its a bit like working out your bank debits accurately if only the balance and credits are given.

  177. Trick says:

    Stephen 8:20am – “Has no one registered…reflectivity…”

    Pretty sure the Garmin et. al. folks have registered atm. cloud reflectivity very effectively.

    http://www8.garmin.com/aviation/brochures/10127GWX68/M021012000910.pdf

    Even my eyes can register the daylight reflectivity of clouds (I can see ‘em!). If my eyes could see in broad IR bands, they would also detect DWIR brightness looking up (and looking down UWIR) as does an IR cloud detector (aka pyrgeometer) even at night. If my IR eyes were sensitive enough then even detect the brightness difference (i.e. different temp. reading of looking up at cloud vs. looking up at clear sky).

    Over time, villains have not suddenly jumped out of clouds or other IR sources so our eyes have not needed to react to IR brightness changes as fair warning of impending doom. But you know, detecting an impending storm would have been useful to enter caves before artificial roofs (and radar/pyrgeometers) invented. So we can see (register) daylight cloud reflectivity.

  178. Stephen Wilde says:

    Trick.

    I think you should read my question properly.

  179. Trick says:

    Stephen 2:53pm – Implies I read the question posed in english improperly. Ok maybe so, I will have to interview to find the questioner’s real hidden intent for a proper answer. Fill me in on the question context exactly to form a more proper answer; shed some visible band light on it. Helps tb if stay on topic – pyrgeometer IR measurement in the invisible band.

  180. Stephen Wilde says:

    There is no hidden intent. It is perfectly clear.

    The sensor only recognises a surface at a given level of reflection so when one points it at clear sky it records a higher colder ‘surface’ than when one points it at a cloud.

    The two readings are therefore not comparable and the temperature recorded is nothing to do with radiative exchange but simply the lapse rate in action.

    The pyrgeometer data is therefore not indicating what AGW proponents say which is extra radiation from the cloud capable of warming the surface.

    It simply measures the lapse rate temperature at a given height with no effect on temperature at the sensor because the temperature of the sensor is set by the lapse rate too.

  181. Trick says:

    Stephen 3:51pm – “…no hidden intent.”

    Your 8:20am question is now even more clear to me, since no hidden intent. My 2:22pm answer for your clear question was proper beginner textbook science. Perhaps the experimental data work by Tim C. at Chilbolton will help improve your understanding of the modern textbook explanations for radar reflectivity physics and pyrgeometer emission/absorption physics.

    The pyrgeometer works (rather coarsely +/- a few % ~4.5 µm to 100 µm) on cloud and clear sky IR emission/absorption since visible band is being mostly filtered out (less than 4.5 µm) by the lens cap so pyrgeometer can’t then “see” the clouds like we can by visible reflectivity. The weather radar works on cloud reflectivity. Weather radar (and defense) guys choose a band where the clear or cloudy sky is very transparent (not absorbing) to their signal so the reflectivity of their transmission can be better measured. Same for IR telescope locations. All those engineers have to “get” atm. radiative physics really well to apply 1st principles of science in the atm. for good benefit.

    Textbooks tell us if you mean by “it” say a handheld IR thermometer (an ~inexpensive one will do fine) given a level of atm. emission at the measurement location so when one points IRT at clear sky it records a higher (in altitude) colder ‘surface’ than when one immediately points IRT at a cloud w/slightly higher T measured at lower avg. altitude.

    Note the IR thermometer is NOT a reflectivity thermometer so I inserted in your comment the correct textbook physics. This would experimentally demonstrate the role of IR active gas in the atm. that the msm likes to call greenhouse effect. If there were no T difference w/IRT immediately pointed at cloud vs. clear sky, then no GHE. There IS a higher T measured when IRT pointed at cloud vs. clear sky at a earth surface location so there IS a surface GHE from IR active gas in the atm. As we know defined from satellite radiometers & near surface atm. thermometers (OLR measured 255K vs. atm. near surface measured 288K).

    Tim C.’s work is on the IR data avg.d over the spectrum as measured at Chilbolton and not on the visible reflection which is much lower power avg.d over the spectrum. I cite for you Bohren’s 1998 text which offers a great description of the physics in reflectivity of clouds.

    Stephen has correctly noted the IRT measured EEL will be lower when a cloud is in the view of the IRT looking up and EEL higher when no cloud is in IRT view. Same effect happens for the radiometers on satellites looking down. Note IR measuring satellites don’t use reflect-o-meters. The satellite data also provide observations of albedo (earthshine) – the fraction of insolation reflectedby cloud & L&O surfaces not emitted back to space as you know. As of 2005, longer global satellite records will be required to discern climate trends in Earth’s albedo.

    Guess I’m in epistle writing mode today. Any more questions (with no hidden intent)? Any answers?

    Stephen continues: “The pyrgeometer data is therefore not indicating what AGW proponents say which is extra radiation from the cloud capable of warming the surface.”

    Correct Stephen, Chilbolton pyrgeometer is not being heated from cooler atm. so if AGW proponents say that then they have the science wrong, since coming from a cooler EEL atm. source the “extra radiation from the cloud” can’t warm the surface but the “extra radiation from the cloud” as measured by the IRT and pyrgeometer CAN slow the cooling of the surface (day and night) after surface has been warmed by the sun. Cite Bohren 1998 & 2006 texts explaining this radiative physics in detail. Or go get an IRT and see for yourself, they are “cool” to play with.

    Stephen even goes on further: “..the temperature of the sensor is set by the lapse rate too.”

    Text tells the avg. atm. temperature of the sensor at Chilbolton near the surface is set by net insolation, emissivity of L&O and emissivity of atm., all globally avg.d spatially and temporally plus weather chaos. The lapse rate starts at that determined near surface temperature and can be plotted as observed (~standard atm.) or as ideal Poisson eqn., pick your flavor.

    Maybe Tim C.’s work can tease some a’ this out of the Chilbolton data. Would be great (if no typo.s above).

  182. Stephen Wilde says:

    “extra radiation from the cloud” as measured by the IRT and pyrgeometer CAN slow the cooling of the surface (day and night) after surface has been warmed by the sun2

    The point is that the difference between the clear sky and cloudy sky readings does not supply evidence of that either way since in the former case the sensor is recording a lower temperature at a greater height and not any change in the rate of energy loss (as compared to the cloudy reading) as normally proposed.

    I am not here saying anything about the net effect of clouds or opacity in general, Just pointing out that IR sensors are not evidence of any change in the rate of energy loss because they change the height at which they measure temperature depending on opacity.

    Their output should not be used as evidence that the rate of GLOBAL energy loss is less under clouds.

    The net effect of clouds globally appears to be one of cooling because the increase in albedo prevents solar energy entering the system in the first place.

  183. Trick says:

    Stephen 9:19pm “…the difference between the clear sky and cloudy sky readings does not supply evidence of that either way since in the former case the sensor is recording a lower temperature at a greater height and not any change in the rate of energy loss (as compared to the cloudy reading) as normally proposed.”

    If not any change in the rate of energy loss then the clear sky and cloudy sky pyrgeometer (or IRT) reading would be the same at Chilbolton but Tim C. clearly writes the data shows Chilbolton instrument is detecting clouds. If different IR flux detected then change in the rate of energy loss (or gain) exists.

    Tim C. 4:12am: “The original objective pyrgeometers and what gives is still there. Still pretty obvious it is essentially a cloud detector.”

    So different flux measured meaning a change in the rate of energy loss as clouds detected as normally proposed supplies good evidence. And same is shown by hand held IRT with different temperature readouts pointing w/cloud & w/clear sky same location/time.

    Radiative physics is the key to understanding Tim C.’s Chilbolton data gathering effort. Not reflective physics. That instrument instantly detects the change in radiative physics when a cloud goes by just like you instantly feel difference in sun load when outside and a cloud covers sun. So slower conduction/convection are not the drivers in this instrument readouts for cloud/no cloud neither is P=density*R*T.

    Stephen continues: “The net effect of clouds globally appears to be one of cooling because the increase in albedo prevents solar energy entering the system in the first place.”

    Now you’re talking debatable stuff worth discussing/researching. Good; global albedo, L&O&A emissivity and insolation matter. But are somewhat off topic to pyrgeometer IR measurement.

  184. Stephen Wilde says:

    The pyrgeometer measures the temperature of the cloud at the height of the cloud which is the same as the temperature of the air at that height.

    When there is no cloud the reduced opacity causes it to measure the temperature of the air at a greater height and due to the lapse rate that height is colder.

    Nonetheless the air at cloud height remains at the same warmer temperature with or without a cloud present due to the lapse rate.

    Therefore there is no change in the temperature at any level when the cloud passes over. All that happens is that the sensor takes a reading at a different height.

    If one could somehow get the sensor to record temperature at the same height as the cloud but without the cloud being present it would record the same temperature with or without a cloud.

    That is different to the change in ‘sun load’ when outside and a cloud covers sun because the sun is a source of fresh energy.

    The sky is not a source of fresh energy and nor is the cloud so the thermal effects of the differing radiative capabilities of both are already fully accounted for in the lapse rate.

  185. tchannon says:

    I’ve been bashing on writing some scripts for creation of data files from the graphic files.

    This sounds trivial, rarely is. Dealing here with autoscaling graphs and legend fonts too poor for OCR (sure I could but I have to do it). Pragmatic fall back on human typing it in but engineers are lazy.

    Also has to work as new data arrives. Think I’ve figured workable methods, lots of simple tricks.
    I’ve decided to add a calibration file to each day archive, has to edited after eyeballing the plots.
    Probably good enough to simply append data day by day. Recreate from scratch is no big deal if needed.

    Theoretically, sure the calibrate ought to be done independently later. Lot of ought in reality.

    Now get that lot handling many files inside archives.

    Got to handle the missing data yet. Missing hour every day is easy to do.

    Looks like two file sets.

    1. by parameter with a row of columns per day (files of humidity, sun, farts, etc.)

    2. Single file time series with parameters by column, can script this from (1)

    Initially do it raw as produced, with silly errors which will take some tricky workarounds, if they matter. Such as a legend key sometimes intruding on data. Another is how the he.. to handle extremely noisy parameters, going to be fun handling wind direction, which wraps.

    Does this sound reasonable?

  186. Be careful assuming that an IR thermometer measures real temperatures of clouds.sky. The IRT is most likely calibrated for a Black Body source. The sky emits radiation from water vapour and GHGs as discrete wavelengths rather than BB.

    See these pages (and others) on the use of a thermal imaging camera on measuring the sky temperature and water vapour temperature.
    http://climateandstuff.blogspot.co.uk/2012/12/water-vapour-and-thermal-imaging.html
    http://climateandstuff.blogspot.co.uk/2012/12/sky-temperature-and-thermal-imaging.html

    The measurement of water vapour at 100C may be surprising to some. It appears as about 35C until it gets converted to a BB by paper placed in its path where it then registers its real temperature of near 100C.

    It should also be understood that O2 N2 etc do not absorb nor emit significant IR. Any temperature measured by the IRT will be from GHGs

    Clouds would be emitting grey body radiation from the water droplets (and discrete wavelengths from water vapour) and would indeed be at the temperature of the air at cloud height and would register as near correct temperature on the IRT.

    GHGs would be absorbing and emitting IR at discrete wavelengths (this would include some of the cloud radiation). The mean free path of a photon of IR emitted from GHGs would mean that the pyregeometer / IRT would be measuring the radiation from these gasses just above the sensor with clear sky. This radiation would be from backradiated energy from the ground plus any lingering heated GHG molecules above. The temperature on an IRT would be incorrect because as stated above it is not BB radiation.

    Pyregeometers do not measure temperature – they measure energy balance..
    A hot object in its field of view emits x quanta of energy picked up on the sensor surface
    The pyregeometer at a known temperature emits y quanta
    The sum of energy the pyregeometer sees is x-y quanta this allows the device to warm to z degC
    A cold object in its field of view emits r quanta of energy picked up on the sensor surface
    The pyregeometer at a known temperature emits y quanta
    The sum of energy the pyregeometer sees is r-y quanta this allows the device to warm to s degC
    An absolute zero object in its field of view emits zero quanta of energy picked up on the sensor surface
    The pyregeometer at a known temperature emits y quanta
    The sum of energy the pyregeometer sees is -y quanta this allows the device to warm to t degC

    The temperature of the pyregeometer is determined in some way (resistance change/thermocouple).
    The quantum of energy carried by one photon of IR will vary depending on its wavelength (shorter wavelength= more energy).

    z is greater than s is greater than t.

  187. Trick says:

    Tim C. 1:14am: “…sound reasonable?”

    It isn’t clear to me what you plan for the weather & flux data once collated. Maybe up thread somewhere? Link or post time? Or lay it out again.

    ******

    Stephen 11:48pm: “The sky is not a source of fresh energy…”

    So to understand this , can you define “fresh energy”? In physical terms please.

    Then add how does the Chilbolton pyrgeometer separately detect this “fresh energy” any differently than non-“fresh energy”? How would Tim C. find “fresh energy” and non-“fresh energy” in the Chilbolton data he’s taken to support your hypothesis about the sky?

    “The pyrgeometer measures the temperature of the cloud at the height of the cloud which is the same as the temperature of the air at that height.”

    The Chilbolton pyrgeometer is measuring flux coarsely from some EEL altitude with cloud and another EEL without cloud. Like the satellite radiometers. It is the IRT reading out in temperature.

    “Therefore there is no change in the temperature at any level when the cloud passes over.”

    Whoa. Not in my experience. I notice for sure the local atm. gets cooler when clouds pass over blocking sun; I put on a jacket as countermeasure to that on certain days. Sun comes out, local atm. warms back up, might take the jacket back off. I observe thermometers near surface register the atm. changed T too with clouds passing, day and night.

    “All that happens is that the sensor takes a reading at a different height.”

    Chilbolton pyrgeometer data is thus experimentally consistent w/GHE.

  188. Stephen Wilde says:

    “the local atm. gets cooler when clouds pass over blocking sun”

    They cut ofd the supply of fresh energy which is new energy arriving at top of atmosphere and filtering to the surface.

    That does change the air temperature.

    If one then excludes that effect the mere passing over of a cloud has no effect on temperature.

    Since there is no fresh energy from the sky or from the cloud it cannot alter temperature either by adding energy or slowing the rate of energy loss.

    When clouds do appear to affect temperature it is due to the advection of a different temperature air mass or the suppression of convection.

    The temperature gradient is then set by the pressure gradient and not the radiative exchange between sky and surface or clouds and surface.

    The sensor will measure the temperature at whatever height it focuses on whether that be cloud or clear sky but either way it is the same temperature for a given height due to the lapse rate.

  189. Trick says:

    Stephen 10:41am: “If one then excludes that effect the mere passing over of a cloud has no effect on temperature.”

    Yet the near surface atm. temperature is different w/cloud vs. no cloud at night (no “fresh energy”). In addition, an IRT or the Chilbolton pyrgeometer data could be used to detect presence of cloud at night.

    “The temperature gradient is then set by the pressure gradient and not the radiative exchange between sky and surface or clouds and surface.”

    Cloud/no cloud at night changes the starting point of the lapse curve. Radiative exchange then does set the temperature lapse curve or gradient even with no “fresh energy”. Note we can’t “see” clouds at night since no reflectivity of the “fresh energy”. If we had IR active eyes, then could see ‘em dudes.

    Stephen – cloud reflectivity and cloud emission/absorption is all discussed in a very interesting way in Bohren’s 1998 and 2006 texts. The written text is very descriptive with orig. art work no need to worry about not getting the math. You will be pleasantly surprised by how much you can learn reading those modern books given your interest.

  190. Trick says:

    TFP2:31am – Yes, to convert flux to temperature the IRT is “pre-programmed” or calibrated with a guess at the BB emissivity of the object (body) being observed.

    As the object (body) emissivity is changed from the “guess” it is easily possible to “fool” the instrumentation. In your experimentation when the object being observed has the emissivity roughly expected, can you still majorly “fool” the IRT or IR camera?

    Pyrgeometers in service are routinely recalibrated to BB source.

  191. Stephen Wilde says:

    “Yet the near surface atm. temperature is different w/cloud vs. no cloud at night”

    The presence of cloud prevents convection and stratus cloud at night is always evidence of warmer air aloft which has advected in from elsewhere.

    It is the warmer air aloft that radiates down rather than the cloud droplets.

    The radiative effects are a consequence and not a cause.

    The IR sensor does not distinguish between warm clear air or warm cloudy air at the same height.

    When it produces a lower temperature under a clear sky it is measuring a higher colder location.

    It isn’t evidence of the different radiative haracteristics of warm clear air or warm cloud droplets at the same height because it doesn’t measure at the same height when the air is clear.

    It does operate as a cloud detector but simply by measuring at a lower warmer height when a cloud crosses the field of view.

  192. Trick says:

    Stephen 3:52pm: Many causes eand effects. The key understanding is in “producing a lower temperature” the lapse rate changes by radiative transfer.

    That’s a key concept that many miss and the physics can be confirmed reading thru Bohren’s 1998 text on the subject. The Chilbolton pyrgeometer data Tim C. is collecting will confirm this understanding of nature also.

  193. Stephen Wilde says:

    The lapse rate is set by the declining pressure gradient and the net radiation flux follows.

    If some other factor tries to change the net radiation flux in order to take the lapse rate (averaged globally) away from that set by gravity then there is simply a circulation change.

    I know you will never accept that so there is no point going further.

    The starting temperature at the ground is then set only by insolation and cannot be affected by air or clouds because they introduce no new energy into the system.

    Nor can air and clouds slow down energy loss because mass is the determining factor as regards the speed of energy throughput.

  194. Stephen Wilde says:

    Or rather ,air and clouds can reduce the speed of energy throughput but ony proportionately to their mass.

  195. wayne says:

    TFP, you almost lost me again. That’s a good description of precisely how a IR camera works spectrally but starting where you describe the temperature of “the device” you have the device “warming” whether the scene is warmer than the camera, same temperature as the camera, cooler than the camera… even if the scene is at absolute zero! You always see warming.

    But I think I do see what you are saying in a weird way, that ‘z’ degC > ‘equal’ deg C > ‘s’ degC > ‘t’ degC at the sensing devices “pixel” surface as seen through the lens. I just wonder why you don’t use the word “cooling” in the case of ‘s’ and ‘t’ temperatures, I’m sure you realize that the cooler ‘s’ case and definitely the ‘t’ absolute zero case can not warm the pixel through the lens. But curiously you use the word “warming” in all four cases. (I inserted the ‘equal to’ case).

    You have worded this in the same manner before. Why?

  196. All effects are measured with respect to the no external radiation i.e. when the eternal temperature is -273C

    so -272 will emit more flux that hits the sensor than zero thus allowing the sensor to warm to a higher temperature than when all objects focussed are -273 and no flux is focussed.

    It reaches a higher temperature that will allow the in flux to equal out flux

  197. tchannon says:

    Smug chuffed.

    First set of output files for a day. Only doing one day at the moment.
    Once this stage is reached it’s defluffing and appraising.

    As expected this is a heck of a lot of numbers so now I have to decide on what are sensible formats.

    Might be a good idea to keep things simple. Changing this only involves the output routine. One take is switch to day files but do I separate different parameters fully?

    I’m now thinking a vertical time series is a better bet.

  198. Bryan says:

    thefordprefect says:

    Deep space at -272 C will ‘warm’ a sensor at a much higher temperature.
    This is a complete distortion of any normal use of the meaning of to ‘warm’

    How many ways can you set out something which seems obvious to most but not TFP?

    Object A is at a temperature of 300K

    Object B is at a temperature of 200K
    Object C is at a temperature of 350K
    Object D is at a temperature of 100K
    Object E is at a temperature of 2.7K

    The only object that can ‘heat’ or ‘warm’ object A is object C.

    IPCC Climate Science explanations often follow the logic of ;

    ‘since object A would lose more heat to entity E than to B then we can say that B has warmed A’

    This is a misuse of language and seems designed to give a misleading impression.
    Whether this is intentional or not is a genuine question.

  199. Bryan
    my statement is the way it is:
    All effects are measured with respect to the no external radiation i.e. when the eternal temperature is -273C

    so -272 will emit more flux that hits the sensor than zero thus allowing the sensor to warm to a higher temperature than when all objects focussed are -273 and no flux is focussed.

    It reaches a higher temperature that will allow the in flux to equal out flux
    ===========
    It is a balance of fluxes – otherwise the object will not have reached a stable temperatures.
    an object recieving 1milli watt per second and 10 watts per second will be receiving a total flux of 10.001watts this will give a stable temperature in its environment of t1
    Remove the 1 milli watt and the object will now be receiving 10 watts. its temperature will be less than t1 assuming the rate of loss of heat is constant for the object.

    What is the natural base temperature of an object in the real world to be able to determine heating and cooling. If it is in a vacuum universe with many heat sources it will have a stable temperature based on input and output energy balance.
    The only reference temperature that can be used universally is that based on its temperature in a vacuum universe of 0K objects. Here there will be no unknown external sources of energy and the temperature will depend only on its loss of energy through radiation.

  200. Bryan says:

    thefordprefect

    You must distort any ordinary meaning of ‘temperature’ and ‘warm’ to end up with deep space at -272C ‘heating’ or ‘warming’ a sensor at a temperature of around 20C.

    Can you find any dictionary that would agree with your use of the word ‘warm’ or ‘to warm’?

    I think that as you look at how the word is used you will realise what a desperate distortion of words and science that the hoax IPCC Global Warming relies on.

  201. Bryan says:

    thefordprefect

    Do you not realise you are using the word ‘warm’ in a ridiculous way?

    Think what nonsense these sentences would make!

    Tim likes to holiday in the Antarctic, he strips naked to get the benefit of the warmth all around him.

    People in satellites in deep space need no insulation as the temperature of -272C will warm them up.

  202. Bryan says:

    thefordprefect

    More ‘warm’ nonsense.

    The radiation detector at 20C is pointed to a building at 10C.
    It is then pointed to a cloud at -10C.
    The detector sensor then ‘warms down’

    TFP find anywhere in the world any printed reference to ‘warms down’.

    After that exercise in futility, find any printed reference to ‘warms up’.

    Yes there are millions!

    TFP, now why do you think that is ?

  203. Bryan says April 16, 2013 at 3:10 pm
    Do you not realise you are using the word ‘warm’ in a ridiculous way?
    ————
    is an object at -272.9999C not warmer than -273?

    I have never knowingly said surrounding yourself with something at -272C will warm you. BUT you will certainly be warmer than if you surround yourself with something at -273C.
    =====================
    Bryan says: April 16, 2013 at 6:25 pm
    The radiation detector at 20C is pointed to a building at 10C.
    It is then pointed to a cloud at -10C.
    The detector sensor then ‘warms down’
    ======================
    Bryan I have never used the term Warmed down!

    A professional IR Thermometer would be calibrated by pointing it into a black body sphere heated evenly to a number of temperatures and the output plotted. The BB would at all temperatures be outputting BB energy spectrum defined by the temperature. note this is energy not temperature that is reaching the thermometer. The sensor in the thermometer is not at absolute zero so it too must be emitting energy. The energy balance of the sensor must be zero for the temperature to stabilise . i.e. the energy lost from the sensor = the energy from the source object (the bb calibration sphere). If the calibration sphere temperature increases then the energy reaching the sensor from the sphere will increase. This means the energy from the sensor must increase to match this. i.e. the temperature of the sensor must increase.
    Whatever the temperature of the sphere the energy hitting the sensor must be matched by the energy lost from the sensor (this is complicated by the materials around the sensor also radiating)

    If the thermometer is reading a steady temperature the energy into the sensor must be the same as the energy out of the sensor. This holds true whatever energy is focussed on to the sensor from cold or hot. Remember you cannot focus cold rays onto the sensor.

  204. Bryan says:

    thefordprefect says

    “Bryan I have never used the term Warmed down!”

    You and the rest of the planet because to say so would be idiotic.

    Yet you will countless number of times used the term ‘warmed up’ because ‘warmed’ implies a temperature increase.

    thefordprefect says:

    “Deep space at -272 C will ‘warm’ a sensor at a much higher temperature.
    This is a complete distortion of any normal use of the meaning of to ‘warm’”

    How many ways can you set out something which seems obvious to most but not TFP?

    Object A is at a temperature of 300K

    Object B is at a temperature of 200K
    Object C is at a temperature of 350K
    Object D is at a temperature of 100K
    Object E is at a temperature of 2.7K

    The only object that can ‘heat’ or ‘warm’ object A is object C.

    IPCC Climate Science explanations often follow the logic of ;

    ‘since object A would lose more heat to entity E than to B then we can say that B has warmed A’

    This is a misuse of language and seems designed to give a misleading impression.
    Whether this is intentional or not is a genuine question.

  205. Bryan says:

    thefordprefect says

    “If the thermometer is reading a steady temperature the energy into the sensor must be the same as the energy out of the sensor.”

    Nonsense

    The temperature of the sensor must be -272C if the object is at -272C for zero flux transfer.

    This shows your statement is patently untrue.

    The temperature of a thermometer at 20C would never have a sensor at -272C unless backed up by a very powerful sophisticated refrigerating system.

    Perhaps you could supply details of this thermometer because it certainly has nothing to do with the topic thread of pyrgeometers.

  206. tchannon says:

    Yay and first art

    The final step adds the data file to the archive.
    Edit calibrate file, add to archive.
    Invoke program giving date.
    That’s it.

    THIS IS PROVISIONAL, SCRUFFY, INACCURATE.
    Ignore the last few data points in the data file.

    http://tallbloke.files.wordpress.com/2013/04/chilbolton-2013-04-14.zip

    Why the 14th? Just the date I was using as a test.

    Rain data is wrong.
    Might add a new configuration item, mode. Needs peak value only.

    End of trace is messy, lot more to do on this. This includes figuring a way where present to automatically kill the graph legend since this is taken as data by the code.

    Output floats are just slightly excessive. Not entirely trivial fixing this as in a universal way. Making it configurable per case is possible.

    None of this is vital, the whole project is casual it’s just that automating a good deal of it makes life easier.

  207. Tim Folkerts says:

    Focus on the science, not the semantics!

    The science is pretty straightforward:
    The photons from any object — even one that is colder than the sensor — will get absorbed by the sensor and give energy to the sensor. This energy — along with other energy the sensor might gain or lose — determines the temperature that the sensor will stabilize to.

    Focusing on whether to say “warms up” or “warms down” or “heats” or “slows the cooling of” or “lowers the temperature less”, etc puts the emphasis in the wrong place.

    ********************************************************************************

    A little more science. FordPrefect said “If the thermometer is reading a steady temperature the energy into the sensor must be the same as the energy out of the sensor” … which is correct.

    dQ = mc dT/dt

    If the thermometer sensor is indicating a steady temperature (ie dT/dt = 0), then the thermal energy into the sensor must equal the thermal energy out of the sensor (ie dQ = 0; the heat is zero).

    Perhaps Bryan was thinking specifically about the IR energy in and IR energy out, which does NOT need to be balanced (since the sensor can also get thermal energy by conduction from the rest of the camera body).

  208. Bryan says:

    Tim Folkers says

    Forget about the language used.

    That’s because no bending of the meaning of words can be used to sustain the cold warms the hotter object theory.

    That IPCC hoax ‘science’ is as bankrupt as the flat Earth theory is becoming increasingly obvious.

    TFP was asked to produce evidence that there is a IR thermometer that requires the sensor to be at -272C for it to measure an object at -272C.

    So far nothing !!!!!!!

    Trust Tim Folkerts (the IPCC chief cheerleader here) to try to save TFP from the hole he has dug for himself.

    But I forgot, asking for evidence ‘is only words’ and the IPCC and its advocates are not very good at either.

  209. Bryan says:

    Tim Folkers .

    There is nothing to stop you being more constructive rather than sniping from the sidelines.

    If you think that TFP is correct then why don’t you give details of the pyrgeometer (or IR thermometer as TFP switches instrument) that requires an Earth bound instrument to have its sensor at -272C , to measure -272C.

    I would certainly be interested in the details of such an instrument.
    Then we could discus the reality or not of TFP’s statements.

    That’s how rational science progresses.

  210. tfp: i mistakingly said:
    the energy lost from the sensor = the energy from the source object (the bb calibration sphere)
    this should have been:
    the energy lost from the sensor = the energy from the source object (the bb calibration sphere)+energy from any heating elements+energy from the body of the thermometer+energy from the lens+energy from the air (GHGs mainly, dust,rain)

    I did then go on to say:
    Whatever the temperature of the sphere the energy hitting the sensor must be matched by the energy lost from the sensor (this is complicated by the materials around the sensor also radiating)

    which I thought covered the other inputs of radiation to the sensor.
    ————-
    Bryan:
    The temperature of the sensor must be -272C if the object is at -272C for zero flux transfer.

    This shows your statement is patently untrue.

    The temperature of a thermometer at 20C would never have a sensor at -272C unless backed up by a very powerful sophisticated refrigerating system.

    If you think that TFP is correct then why don’t you give details of the pyrgeometer (or IR thermometer as TFP switches instrument) that requires an Earth bound instrument to have its sensor at -272C , to measure -272C
    ———-
    TFP: I have never said that the sensor temperature must be -272C to measure a tempeature of -272C
    I said:
    All effects are measured with respect to the no external radiation i.e. when the eternal temperature is -273C

    so -272 will emit more flux that hits the sensor than zero thus allowing the sensor to warm to a higher temperature than when all objects focussed are -273 and no flux is focussed.

    It reaches a higher temperature that will allow the in-flux to equal out-flux

    I have not said what temperature the sensor has to be.
    It could be, e.g. 1000C when measuring an object of -272C. But when it measures an object of -273C its temperature will go lower say to 999.99999999999999C. Similarly when measuring a temperature of -271C its temperature will go higher than when measuring -272C say 1000.0000000000001C – THIS ASSUMES THAT THE THE SENSOR TEMPERATURE HAS REACHED A STABLE VALUE.

    tfp: I have never knowingly said surrounding yourself with something at -272C will warm you. BUT you will certainly be warmer than if you surround yourself with something at -273C.

  211. Bryan says:

    thefordprefect says

    “If the thermometer is reading a steady temperature the energy into the sensor must be the same as the energy out of the sensor.”

    Since we are talking about a radiative exchange then radiative flux in, from object at -272C must equal the radiative flux out from the sensor.

    This can only be true if the sensor is at -272C or even less!!!!.
    The flux from a distant source will be subject to a 1/R^2 decrease.
    Also how does a sensor at presumably 20C radiate as if it was at -272C ?

    Put some numbers in joules or watts from all sources to firm up your conjecture.

    I think to sort out your ideas you will need to specify the sensor being used.
    Is it a thermistor type or a thermopile or some other?
    These both operate with different physics principles.

    Are we discussing an IR thermometer or a pyrgeometer.
    Give a model so we can get real.
    You drift from one to the other.

    I notice that you now accept that only IPCC ‘science’ uses ‘warming’ to mean the effect of cold objects on warmer objects otherwise you would have given examples.

  212. Tim Folkerts says:

    Bryan says: “Tim Folkers says ‘Forget about the language used.’ “
    No, I said to FOCUS on the science. But it is quite possible to focus on one thing without forgetting about everything else.

    Bryan says: “That’s because no bending of the meaning of words can be used to sustain the cold warms the hotter object theory.”
    I would say the OPPOSITE. Using words instead of equations ALLOWS people to quibble about what is meant by some vague phrase like ‘the cold warms the hotter object theory’.

    Conversely, using math like ‘ΔU = Q + W’ makes things much more definite and much more focused.

    I suspect that your “cold warms the hotter object theory” objection is really a version of the 2nd Law of Thermodynamics — that entropy must always increase. So if you think there is a problem with the 2nd law in something that someone says, then show how their scenario is decreasing the entropy of the universe.

    Bryan says: “Trust Tim Folkerts (the IPCC chief cheerleader here) … “
    I have said nothing about IPCC or even climate here. I would accept the title “Chief Textbook-Science Cheerleader” since I do keep pushing the standard science that has been presented in physics textbooks for 100 years. :-)

    Bryan says: “There is nothing to stop you being more constructive rather than sniping from the sidelines. “
    I think that if you look back through the thread, that you will see that I have provided some rather specific, constructive, scientifically-based comments.

    I notice that when I DID give specifics, you ignored them. :-(

    Bryan says: “… why don’t you give details of the pyrgeometer … that requires an Earth bound instrument to have its sensor at -272C , to measure -272C”
    As has been pointed out a couple times now, that is a strawman argument. Only your misunderstanding continues to push this idea.

    The sensor …
    * gains energy from IR photons that hit it
    * loses energy from IR photons that leave it
    * gains/loses energy from conduction (and maybe radiation and convection) with the “case” of the thermometer.

    In a typical design, the temperature of the sensor will change until the net energy in = zero. The temperature of the sensor will be a function of all three energy flows. Since two of these (IR energy out and conduction to/from the case) can be pretty well estimated or controlled, then the third energy flow (energy in via IR photons) can be determined.

    The sensor does not need to be at -272 C to be affected by photons from -272 C objects.
    The sensor does not need to be at -272 C to have a net energy balance of 0 J/s.

    (Of course, this is basically what TFP has already said, but sometimes hearing it twice — or with different words — can help.)

  213. Bryan says: April 17, 2013 at 12:46 pm April

    Since we are talking about a radiative exchange then radiative flux in, from object at -272C must equal the radiative flux out from the sensor.

    Bryan you did not read what I said – The whole of the body, the electronics, the lens, the ghgs in the unit are heating the sensor, as is the image through the lense. Nothing can cool the sensor – heat pumps excepted)
    assume the sensor at 20C is at 20C only when pointing at -273C object
    then when pointed at an object at -272C the sensor will be warmer say 20.000000001C
    when pointed at an object at 100C the sensor temperature will be perhaps 21C

    so you see, any change in object temperature will result in the sensor temperature changing
    ———
    b: This can only be true if the sensor is at -272C or even less!!!!
    ———
    tfp: Its energy balance that is all it does not matter what the sensor temperature is.
    ———-.

    b: I think to sort out your ideas you will need to specify the sensor being used.
    Is it a thermistor type or a thermopile or some other?
    These both operate with different physics principles.

    Are we discussing an IR thermometer or a pyrgeometer.
    Give a model so we can get real.
    You drift from one to the other.
    ——————
    tfp: type of sensor is not important it is only energy in to energy out balance that is important IR thermometer/pyregeometer are similar.
    A thermistor sensor has additional problems since it has to have a voltage across it. This causes self heating (which can be corrected by software). A thermopile has to have a reference junction (known temperature) – the “cold” junction. The temperature of this junction has to be measured to correct the voltage generated.
    ————————————–
    b:I notice that you now accept that only IPCC ‘science’ uses ‘warming’ to mean the effect of cold objects on warmer objects otherwise you would have given examples.
    ————–
    tfp: please explain what you are requesting I do not understand.

  214. Bryan says:

    TFP says

    “so -272 will emit more flux that hits the sensor than zero thus allowing the sensor to warm to a higher temperature than when all objects focussed are -273 and no flux is focussed.”

    “the energy lost from the sensor = the energy from the source object”

    “type of sensor is not important it is only energy in to energy out balance that is important IR thermometer/pyregeometer are similar.”

    Tim Folkerts agrees.

    Now the pyrgeometer (I assume that is what we are discussing ) has a passive detector unit.
    It contains no battery.
    TFP says quite clearly in the above quote that this passive unit at the ambiant temperature has this temperature increased when pointed to an object at -272C
    In any radiative exchange there will be much more radiation leaving the sensor unit at say 20C than enters it from -272C

    I will repeat this as Tim and TFP are of the opposite opinion

    In any radiative exchange there will be much more radiation leaving the sensor unit at say 20C than enters it from -272C

    So in the example given

    The net effect is to cool the sensor.

    Cool means its temperature will drop below what was its ambiant temperature.

    What part of this does TFP and Tim Folkerts fail to understand.

    TFP ends by saying

    ” please explain what you are requesting I do not understand.”

    For once I tend to agree.

  215. Bryan says:

    Tim Folkerts says

    “I would accept the title “Chief Textbook-Science Cheerleader”

    To prove it he proudly produces two equations which are rather trivial
    In terms of UK education these equations would be met by pupils around the age of

    dQ = mc dT/dt…….thirteen ……but you have wrong equation here …..check units!

    ΔU = Q + W’…….Eighteen.

    Not very impressive for a Chief Textbook-Science Cheerleader

    As I said above IPCC Climate Science explanations follow the logic of ;

    ‘since object A would lose more heat to empty space than to any other object then we say that B has warmed A’

    This misuse of language is designed to give a misleading impression.
    Only IPCC ‘science’ use this distortion

    Isn’t it pathetic how they clutch at such an obvious distortion!

  216. Bryan
    TFP says quite clearly in the above quote that this passive unit at the ambiant temperature has this temperature increased when pointed to an object at -272C
    In any radiative exchange there will be much more radiation leaving the sensor unit at say 20C than enters it from -272C
    ———–

    Please please please read what TF and I actually say and look at the number example I gave.

    -273C will not radiate onto sensor
    -272C will radiate onto sensor
    +1000C will radiate onto sensor

    With all temperatures greater than -273C the temperature of the sensor will be hotter than the sensor temperature with -273C focussed onto it (all other energy being constant)

    I cannot say it more plainly.

  217. Bryan
    ‘since object A would lose more heat to empty space than to any other object then we say that B has warmed A’

    This misuse of language is designed to give a misleading impression.
    Only IPCC ‘science’ use this distortion

    Isn’t it pathetic how they clutch at such an obvious distortion!
    —————————-
    which is warmer 19.000000000000° or 19.000000000001°C
    I would suggest that 19°C has warmed by 000000000001°C

  218. Tim Folkerts says:

    Bryan states: “In any radiative exchange there will be much more radiation leaving the sensor unit at say 20C than enters it from -272C

    I think we can all agree with that.

    Bryan continues: “Now the pyrgeometer (I assume that is what we are discussing ) has a passive detector unit.”
    Here is a link to a “typical” pygeometer — just so we can be ‘on the same page’. They don’t give FULL details about the construction, but detector here does seem to be passive with no battery power, as you describe.
    http://www.kippzonen.com/?download/36152/CGR+Pyrgeometers+-+Brochure.aspx

    Bryan continues: “Cool means its temperature will drop below what was its ambiant temperature.”
    I think the focus should be on that vague word “it”. We need to be careful which “it” we are talking about — the body around the sensor, or the sensor itself. (And there is also the “target” that the sensor is aimed at, which can be at a different temperature yet.) .

    As I said, the full details about he detector are not in the linked brochure, , but the principle seems pretty straightforward.
    * There is a thermometer to determine the temperature of the body.
    * There is a separate thermometer to determine the temperature of the sensor.

    The thermometer on the sensor lets us determine the power of the IR radiation leaving the sensor using Stefan-Boltzmann Law.
    The difference between the two thermometers lets us determine the power conducted to the sensor from the body.
    The difference between the power conducted to the sensor and the power radiated from the sensor will give us the power radiated TO the sensor from the target.

    So the body is at “ambient temperature”. The sensor cools below that ambient temperature by radiating to the target = ‘the cool sky’. The cooler the sky, the cooler the sensor will be, since there will be less radiation returning from the target to the sensor.

    Let me repeat — the cooler the sky, the cooler the sensor will be. If the sky is at -273 C, the sensor will be as cold as possible. If the sky is “warmed” to -272 K, the sensor will warm. The radiation from the -272 C sky will warm the sensor compared to the temperature it was with a -273 K sky.

    To say that another way, the “ambient temperature” of the sensor could be taken as the temperature the sensor would be when the body is at some temperature and the target is “nothing” = 0 K. (The “nothing temperature might better have been given as 2.7 K cosmic background temperature, but that is a trifling detail.) Aiming at “something” — even something only slightly warmer than 0 K — will raise the sensor above the “nothing” temperature.

    *********************************************************

    I think all of that is consistent with what both TFP and I have been saying all along.

    That is ALSO quite similar to the “warming” of the earth’s surface by the atmosphere. The “ambient temperature” of the earth when surrounded by the 2.7 K nothingness of outer space is ~ 255 K. If the earth is instead surrounded by an atmosphere that is warmer than 2.7 K, then the surface will “warm” above ~255 K due to the presence of the presence of the atmosphere — EVEN IF that atmosphere is cooler than 255 K (since it is ABOVE 2.7 K).

  219. Tim Folkerts says:

    PS … yes, I did leave out the “/dt” on the right side of the equation. But even cheerleaders are allowed occasional typos. :-)

  220. Tim Folkerts says:

    Bryan says mockingly: “‘since object A would lose more heat to empty space than to any other object then we say that B has warmed A’

    I find it fascinating that Bryan can articulate the concept, but seems to more intent on the semantics than the science.

    HOWEVER YOU WANT TO SAY IT — the temperature of the sensor depends on the temperature of the target.
    With “nothing” there (2.7 K), the sensor (Object “A”) will be one temperature.
    With “something” (Object “B”) there (even if it is only 3.7 K), the sensor will be a higher temperature.

    That is the science. it is only semantics whether you want to call this “to warm” or “to reduce the cooling” or “to raise the temperature” or “zu erwärmen” or “à réchauffer”. (I personally would NOT call it “to heat” because “heat” has a very specific technical meaning in thermodynamics, but even so,most people who understand the science would be able to see beyond the semantics to the meaning.)

    ********************************************************

    Similarly …

    The earth would be ~ 255 K without the effect of the atmosphere.
    The earth is ~ 288 K with the effect of the atmosphere.

    I have absolutely no problem saying that adding the atmosphere has “warmed” the earth.

  221. donald penman says:

    I think that the sensor measuring the target temperature does not have to take on the temperature of the target because the ambient temperature is removed mathematically not in reality, I read this in the information provided by the manufacturers.I think that what is being measured is the flow of IR between the sensor and the target.I am not sure if we actually have a target if we just point the thing at a clear sky, it may be that the instrument has a maximum range that is the default when there is no target.

  222. tchannon says:

    donald penman,

    Yep.

  223. Tim Folkerts says:

    Don, I like what you say except for ” it may be that the instrument has a maximum range that is the default when there is no target.”

    Such instruments do not have a “range” per se. They take in whatever IR hits them — whether it came from 1 mm away or 1 million light years away. The instrument has no way of knowing.

  224. Stephen Wilde says:

    “I am not sure if we actually have a target if we just point the thing at a clear sky, it may be that the instrument has a maximum range that is the default when there is no target.”

    That comes back to the point I raised earlier.

    If it points at a clear sky then the ‘target’ becomes the height at which the optical depth causes the sensor to interpret a ‘surface’ which it then ‘measures ‘.

    If the atmosphere is completely opaque it will measure the temperature right in front of the instrument.

    If the atmosphere is completely transparent it will measure the temperature of space.

    So the temperature that the sensor records when pointed at a clear sky is the temperature at the height at which the optical depth allows it to recognise a surface that it can measure.

    That will always be a different height to that recorded when a cloud enters the field of view.

    So it isn’t measuring a change in net radiative flux at all. It is simply recording the temperature at different heights and those temperatures are dependent on the lapse rate not the net radiative flux.

    It is not providing data the indicates anything about the radiative flux at all.

  225. Bryan says:

    Tim Folkerts a.k.a Chief Textbook-Science Cheerleader exhorts us to use equations rather than language.
    This is because no distortion of any meaning of ‘warm’ is sufficient to cover object at -272C warming object at 20C

    But then he writes down an equation that is nonsense.

    I pointed this out to him, but instead of thanking me he slips in.

    “PS … yes, I did leave out the “/dt” on the right side of the equation. But even cheerleaders are allowed occasional typos.”

    This is no spelling mistake but an ‘equation’ that does not balance.!

    Another misuse of an equation by the Great Cheerleader is when the pyrgeometer gives a steady reading.

    Tim then assumes

    dT/dt = 0

    Or in language terms the object at -272C is at the same temperature as the sensor.

    If Tim or TFP disagree let them put in their own value of the sensor temperature.

    dT/dt = 0 … will only be true when the pyrgeometer at 20C points to an object at 20C.

    If object is less than 20C (the usual situation) net radiation will flow from pyrgeometer to object.

    If object temperature is greater than 20C net radiation will flow to pyrgeometer from object.

    I will repeat again an object at -272C will never be in equilibrium with a sensor at 20C

    donald penman above has it spot on.

    The pyrgeometer above works on the basis of knowing its own temperature and estimating from its radiation loss or gain what radiation is leaving the object.

    I’m glad that we are now discussing a real pyrgeometer and hope that we will refer to it in further comments

  226. Tim Folkerts says:

    Bryan.

    1) dT/dt does NOT mean ” the object at -272C is at the same temperature as the sensor” ! You have wrong equation here …..check units!

    This equation means that the rate of change of temperature of the sensor is zero, ie the temperature of the sensor is not changing. It has NOTHING to do with the temperature difference between the sensor and the object it is aimed.

    2) I am impressed that you caught the error by checking the units. Dimensional analysis is a very powerful technique that works even when people don’t really know what the equation means. I would have been EVEN MORE impressed if you had realized
    a) the equation clearly comes from Q = mc ΔT
    b) the next line clearly was intended to be to differentiating both sides with respect to time to get
    dQ/dt = mc dT/dt
    c) The difference between what was written and the “correct” equation is simply the “/dt” that was left of in haste.

    **********************************************

    The rest of what you say is basically repeating what we all agree on — that the net radiation will always be from the warmer object to the cooler object.

    The equilibrium (or more precisely, the “steady-state condition”) that TFP & I are talking about is the sensor itself — that the sensor will reach a steady temperature where the total power in (from the target and the case of the pyrgeometer) equals the total power out (to the target).

  227. bryan:
    I will repeat again an object at -272C will never be in equilibrium with a sensor at 20C
    —————–
    If all temperatures are static then all objects/pyrgeometers/sensors are in energy balance .
    ie.
    total energy in =total energy out in the same time frame.

    the sensor energy comes from local sources (including self heating if resistive sensor is used), electronics, case, optics, unit window etc. it is energy it is not temperature and energy does not know from what temperature it originated. It can only be positive energy. added to the local sources will be whatever energy the sky is generating this is positive energy and the energy does not know what temperature it originated from, or how far away its origin.
    add ALL energys together and knowing the rate of loss of energy you can work out a temperature for this combination of inputs. If one source changes e.g. the lens is cooled by water evapourating from it then the temperature of the sensor changes. All sources of energy in the pyrgemeter need calibrating out excluding of course that coming through the 180deg view window.

    The energy through the window is purely lw IR (the window and filters assure this is so). Assuming that there are no solid objects (not sure about clouds) in the 180deg view above then only ghg emissions and cloud emissions will pass through the window.

    These are discrete ranges of wavelength not black bodies. O2 and N2 will not be transmitting any IR. I may be wrong but I believe that the mean path of IR photons is very short at 1 atmos. So the GHG emissions will be from close to the pyrgemeter.

    Put an opaque cloud above the pyrgeometer and I believe this appears more like a BB radiating
    a bb range of frequencies.

    The discrete bands of frequency from IR GHGs do not register the temperature correctly – they have been calibrated as if the IR was from a BB. They expect to be focussed on a solid at a certain distance.

  228. Tim Folkerts says:

    Ford Prefect,

    For a pretty good calculation of what the actual IR spectrum would look like in various cases, try MODTRAN ( http://forecast.uchicago.edu/Projects/modtran.html ). You can add or remove clouds, vary the CO2, compare winter vs summer, look up from the surface or down from a satellite, etc.

    Yes, clouds will be basically BB radiation.
    On a clear day, the IR will come from GHG’s (and aerosols).

  229. thanks TF
    As I said the mean free path for GHG radiation will be small so measured DLWIR from GHGs will be from close to sensor.

    Radiation from the cloud will be absorbed and re-radiated in all directions by the GHGs but only in the bands that GHGs absorb. This will reduce the cloud IR in the absorption bands by up to 0.5.

    The rest of the cloud radiation will reach the sensor directly from the cloud (although some will be absorbed by aerosols to be re-radiated with BB specra)

  230. Bryan says:

    Tim Folkerts a.k.a Chief Textbook-Science Cheerleader says

    “I would have been EVEN MORE impressed if you had realized
    a) the equation clearly comes from Q = mc ΔT”

    [Snip]

    The only way that the sensor will have dT/dt = 0 is when pointed at an object at the same temperature as itself i.e. 20C.

    When the display unit gives a steady value it does so after working out via an elaborate equation an unchanging value.
    Its a dynamic situation involving a number of factors, look at the equation
    In the example quoted of pyrgeometer at ambient temperature of about 20C involved with a radiative exchange with object at -272C part of the sensor facing object will be coldest and other parts warmer having better contact with pyrgeometer.
    So the idea that a steady reading means that all parts of the senor are at the same temperature is wrong.
    There will be a large flow of heat from the sensor to the cold object at -272C in this situation

  231. Tim Folkerts says:

    Bryan,

    You are still not getting it. dT/dt means the rate at which the temperature of a given object is changing temperature. This requires measuring the temperature of one location at two different times, not measuring the temperature of two different locations at one time.

    Bryan says“In the example quoted of pyrgeometer at ambient temperature of about 20C involved with a radiative exchange with object at -272C part of the sensor facing object will be coldest and other parts warmer having better contact with pyrgeometer.”

    Yes.

    dT/dt for the -272 C object is 0 K/s
    dT/dt for the 20 C body of the pyrgeometer is 0 K/s
    dT/dt for the sensor of the pyrgeometer is 0 K/s (after it has been pointed at -272 C object for a while).

    If you point the pyrgeometer at some other object, then dT/dt for the sensor will (temporarily) not be 0 K/s. If we switch to a warmer object, then dT/dt will be positive as the sensor warms up a little. During this time, the pyrgeometer will read a temperature somewhere between the temperature of the old object and the temperature of the new object. Eventually (within about 18 seconds according to the brochure for the Kipp & Zonen pyrgeometer), the sensor will stabilize at a new temperature and dT/dt will again be zero and the instrument will read the temperature of the new object.

    “So the idea that a steady reading means that all parts of the senor are at the same temperature is wrong.
    I think maybe you are confusing the concept of dT/dt with the concept of dT/dx. We all agree (I am 99.99% sure) that the “face” of the sensor will be cooler than the “back” of the sensor (when pointed at a cool sky).

    Indeed, measuring the difference is indispensable. That difference tells us how much heat is being conducted through the sensor. This in turn tells us how much heat is being radiated from the surface (but only when dT/dt is zero as well, so dU/dt will also be zero).

  232. Bryan
    Heres an experiment you can try
    Make some 0C water in a jar – crushed ice a little water then leave it until the ice starts melting.
    paint a thermometer bulb matt black/grey/any MATT oill based paint .
    place the thermometer in a draught free location away from heat sources in your room (above 0C!) and measure the temperature when stable
    place the jar containing ice and water mix within 2 cm of your thermometer
    when the temperature stabilises I am willing to bet it does not measure 0C
    It will measure less than room temperature (you have replaced nearly 50% of objects at room temperature radiating towards the bulb and substituted glass at 0C radiating towards the bulb.

    Note: the amount of radiation FROM a BB (the bulb of the thermometer) depends on the temperature of the BB only the temperature of its environment does not change the radiation exiting the BB (if the initial temperature is the same) There is no environment temperature variable in thebb radiation equations

  233. Bryan says:

    Tim Folkerts says:

    “Eventually (within about 18 seconds according to the brochure for the Kipp & Zonen pyrgeometer), the sensor will stabilize at a new temperature and dT/dt will again be zero and the instrument will read the temperature of the new object.”

    What page of the Kipp & Zonen pdf gives this information

  234. Bryan says:

    TB or whoever

    How come Tim F gets to make sneering comments but when I reply in kind it gets snipped?

    [reply] He doesn’t. So if one got past, give me the date stamp. – Rog

  235. Bryan says:

    TFP says

    “I am willing to bet it does not measure 0C
    It will measure less than room temperature (you have replaced nearly 50% ”

    Its getting very hard to know what your on about.

    The room is at 20C (say) before introducing the ice – water mix

    You then apparently say that the thermometer will read less than 20C

    Agreed but what point are you trying to make?

  236. Bryan says:

    TB read April 18, 2013 at 12:46 pm

    Tim Folkers after I had corrected him for putting in the wrong equation then says

    “I would have been EVEN MORE impressed if you had realized
    a) the equation clearly comes from Q = mc ΔT”

    Note the ‘YOU’

    Tim after making a hash of this simple equation implies that I am not aware of its correct equations existence.

    This low level sniping by Tim is persistent and will drive others to the point of exasperation.

    If I on the other hand had made a hash of an equation I would not give a sneering reply to the person that pointed it out .

    So I think that my snipped comment was fully justified.

    [Reply] I’m certain you are able to deal scientifically with what you perceive to be sniping without resorting to the use of the words I snipped.

  237. Tim Folkerts says:

    Bryan, look for the “response time” to see how quickly the instrument adjusts to new conditins — for example here:
    http://www.kippzonen.com/?product/16132/CGR+3.aspx

  238. Bryan says: April 17, 2013 at 12:46 pm

    Since we are talking about a radiative exchange then radiative flux in, from object at -272C must equal the radiative flux out from the sensor.

    This can only be true if the sensor is at -272C or even less!!!!.
    The flux from a distant source will be subject to a 1/R^2 decrease.
    Also how does a sensor at presumably 20C radiate as if it was at -272C ?

    later
    TFP says
    “I am willing to bet it does not measure 0C
    It will measure less than room temperature (you have replaced nearly 50% ”

    Its getting very hard to know what your on about.
    The room is at 20C (say) before introducing the ice – water mix
    You then apparently say that the thermometer will read less than 20C
    Agreed but what point are you trying to make?
    ————————————–
    tfp:
    Your statement that the sensor will have to be at -272 for radiative balance is what I am trying to disprove.
    From your first comment I assumed you would expect the temperature to read 0C.

  239. tchannon says:

    Phew… I’m exhausted, moved from code bashing to data editing, looking at all the plots and editing the plot limits as necessary.

    Looks like it is then hit update the archives with the edited configurations and invoke a high level script which munches all the plots to data and new plots which takes, dunno, 15 minutes. And I still haven’t done loads of housekeeping stuff. Think it is workable enough to show results warts and all.

    I showed a plot earlier with 10 graphs. That is now 12, with the last one where all the fun will start.

    There is going to be a surprise.

    I am looking for a volunteer who can remain anon or mentioned. I need someone to go through all the zip archives (61 to date, 600 or so files) checking the plot limits match the text configuration files, looking for my mistakes.
    Boring job. See why I am tired?

    Apart from being able to take a fair size data file, no special tools. Text editor and plot viewer.
    If you want to be anon and don’t have my email, portal at top, there is a contact form in there, Rog sees this too. If that is a problem, err… comment on my blog which will say in moderation which I can intercept.
    Task could be split if it would be easier to have several help out.

  240. Bryan says:

    TFP
    Once again ts getting very hard to know what your on about.
    The room is at 20C (say) before introducing the ice – water mix
    You then apparently say that the thermometer will read less than 20C
    Agreed but what point are you trying to make?

    Has it occurred to you that heat can be transferred by other means apart from radiation?

  241. Bryan says:

    TF

    Have a look at the calibration equations although it seems to be still a matter of debate which is the best one.
    The voltage across the thermopile is fed into an analysing process.
    Dome temperature ,Case temperature also are required to be known.

    The displayed value is the best guess at what the DWLR/m2 is.
    You and TFP seem to be saying that all that needs to be done is to get the thermopile voltage to equal zero.
    A careful reading will show that this is wrong.

    http://www.arm.gov/publications/proceedings/conf16/extended_abs/stoffel_t.pdf

  242. Bryan
    You and TFP seem to be saying that all that needs to be done is to get the thermopile voltage to equal zero.
    A careful reading will show that this is wrong.
    ================
    yes it is wrong.
    This would require active heating or cooling of the back side of the thermopile.

    All you need is a stable front temperature. Using temperature measurements from back surface of thermopile, and window temp ( to be able to subtract the effect of IR emitted from the window – but not all units do this)
    Calibration is done using a BB sphere.
    Software can very simply use equations or interpolation to provide the w/sqm output.

  243. Bryan says:

    TFP

    I’m glad you now realise that the sensor voltage (or the thermopile voltage) will not be zero.
    The link provided makes it clear that the thermopile voltage is only one part of the input required for a calculation and display of DLWR/m2.