Trenberth's Energy Budget

Discussion in 'Environment' started by IanC, Oct 23, 2011.

  1. IanC
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    IanC Gold Member

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    [​IMG]

    how many of you think it is a deception to have 390 (W/m2) going up and 324 coming down? while it is true in an absolute way it disguises the fact that only 66 w/m2 is available as the difference between the temps of the surface and the lower atmosphere. out of that 66, 40 leaves directly with only 26 W/m2 warming the lower atmosphere.

    so 26 W/m2 is the greenhouse effect and I have never seen any estimates higher than 26% for CO2's share of the GHE so that means ~8 W/m2 or less for the total amount of CO2. the absorption of CO2 is logrithmic so that means we are into the ninth doubling (256-512) so every doubling is ~(8W/m2)/8 doublings= 1 W/m2 or less.

    I find it hard to believe that something that is responsible for ~1 W/m2 is the grand control knob of the climate. it is an amount that is lost in the error bars of measurement. but that is just my opinion but now you know why I think that way.

    [​IMG]
     
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    Last edited: Oct 23, 2011
  2. code1211
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    code1211 Senior Member

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    Yeah! What HE said!.
     
  3. Mr. H.
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    Mr. H. Diamond Member

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    Looks like a coronary bypass.
     
  4. Mr. H.
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    Mr. H. Diamond Member

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    That would be a handsome accompaniment to your foil hat.
     
  5. IanC
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    IanC Gold Member

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    does everybody understand the conceptual difference between the 168 W/m2 coming from the sun that is available to directly heat an object, and the 324 W/m2 backradiation that can only counteract part of the 390 W/m2 upward radiation from the surface? on a cloudy day you feel immediate warmth when the sun peeks through.
     
  6. IanC
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    IanC Gold Member

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    I forgot to note that the Sun's 168 W/m2 is mostly higher energy photons than the radiation from and back to the earth, which would also affect why it seems warm when the sun comes out
     
  7. wirebender
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    wirebender Senior Member

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    There is no energy coming back to the earth.

    Second Law of Thermodynamics: It is not possible for heat to flow from a colder body to a warmer body without any work having been done to accomplish this flow. Energy will not flow spontaneously from a low temperature object to a higher temperature object.

    Second Law of Thermodynamics

    Clausius statementGerman scientist Rudolf Clausius is credited with the first formulation of the second law, now known as the Clausius statement:

    No process is possible whose sole result is the transfer of heat from a body of lower temperature to a body of higher temperature.

    Spontaneously, heat cannot flow from cold regions to hot regions without external work being performed on the system, which is evident from ordinary experience of refrigeration, for example. In a refrigerator, heat flows from cold to hot, but only when forced by an external agent, a compressor.



    Which part of "not possible" and "will not" is it that you guys don't understand. "Net" energy flow is a fiction, a fabrication, a concoction, a fable, and a falsehood invented by people to whom the actual second law of thermodynamics is an inconvenience.

    Of course, if you can show some observable, repeatable experimental evidence that proves otherwise, I would be very interested in seeing it as it would be the basis for a damned profitable perpetual motion machine.

    BTW, absorption and emission by CO2 molecules does not constitute work.
     
    Last edited: Oct 24, 2011
  8. flacaltenn
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    flacaltenn USMB Mod Staff Member Gold Supporting Member

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    I've stared at this before -- and no it's not illogical to have 390 going out with 324 bouncing back. That's the heat loss rate of the earth that HAS to happen at night when the left side of the diagram is not operating. Futhermore, we know that the heat loss at night would be mitigated by cloud and atmospheric conditions. So as far as your calculations for CO2 contribution -- you could be right.

    Part of the confusion is that the Trenberth numbers are for heat FLOW RATES, not energy. The earth and atmosphere is a heat battery that gets charged by the left side rates and discharged by the right side rates. So "average rates" aren't very meaningful unless you consider the CAPACITY of the various components to store energy. Add water vapor and greenhouse gases and that CAPACITY increases in the atmosphere. So even if the rates didn't change (they would) -- the ability to coast thru a colder night is increased by the storage capacity. Can't really analyze the dynamics of temperature change without the time and capacity factors.

    2nd -- the right side of the chart is happening all day long. It's just easier to see it's sum contribution by considering it at nighttime. Whereas the left side is operating at VARYING efficiency all day long. So the rate of heat charge to replace loss at night has to EXCEED the sum discharge rate on the right side. That's why when you find the net discharge to be 66w/m2, -- it's no surprise that the net CHARGE rate is closer to 168w/m2. That's MORE then double the net discharge -- which makes perfect sense because of "daytime variability" of power coming in.

    So yeah --- after staring at it a couple times, it passes the first level reasoning that at least I can apply to it...
     
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  9. flacaltenn
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    flacaltenn USMB Mod Staff Member Gold Supporting Member

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    One thing that could be looked at more BTW --- is that we are concentrating on the energy balance at the earths surface.. That is just ONE of the TWO major heat storage systems in the diagram. Even if we could affirm "balance" at the surface of the earth, there is still "balance" in the temperature of the atmosphere which has DIFFERENT flow rates associated. Could be that more energy is being stored in the atmosphere than actually at the surface. Thus modifying the "back radiation" value. In fact, it's a little flaky that I see about 200w/m2 going OUT of the atmosphere, but LESS than that coming in.. That can't proceed that way for very long -- can it... !!!

    But I thought that they've scratched their heads about not finding the predicted warming at higher altitude that the GHG folks expected..
     
    Last edited: Oct 24, 2011
  10. wirebender
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    wirebender Senior Member

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    That budget isn't based on a model that has a left and a right side. That model is based on a flat earth that is receiving sunlight 24 hours a day at a rate of 1/4 of actual. There is no dark side of the earth associated with that model and as a result, a greenhouse effect is necessary to explain the observed temperature.

    If you model the earth as a sphere that is being radiated across 180 degrees of its surface and dark across 180 degrees of its surface, no greenhouse effect is necessary to account for the observed temperature of the earth.
     

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