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Seeking Peer-Reviewed Studies of Water Vapor Feedback

  1. Mar 14, 2009 #1
    One of the key factors in determining the climate sensitivity to the increasing atmospheric concentration of CO2 and other long lived greenhouse gases is the response of water vapor to the relatively small warming induced by these gases. Climate models produce a strong signal of positive water vapor feedback, while actual measurements taken over the past few decades seem to indicate otherwise if some of the popular skeptical blogosphere presentations are to be believed (specific humidity is purportedly shown to be decreasing). Water vapor feedback is indeed positive near the surface in the planetary boundary layer, but what about higher up in the mid and upper troposphere where the critical impact on enhancement to the greenhouse effect would take place? Can anyone here come up with peer-reviewed studies of this issue?
     
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  3. Mar 14, 2009 #2

    ZapperZ

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    What about:

    1. B.J. Soden et al., Science v.296, p.727 (2002).
    2. http://www.gfdl.gov/~gth/netscape/1999/adh9901.pdf [Broken]
    3. D. Rind et al. Nature v.349, p.500 (1991)

    Zz.
     
    Last edited by a moderator: May 4, 2017
  4. Mar 14, 2009 #3

    Gokul43201

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  5. Mar 14, 2009 #4
    I do not know if these are what you are looking for:
    The issue is related to something that Forster & Taylor (2006 J. Climate) and Forster & Gregory (also 2006 J. Climate) have previously demonstrated: In order to estimate radiative feedbacks, you must first remove any sources of time-varying radiative forcing from the data. No one has ever bothered to do this for the time-varying radiative forcing due to natural cloud variations in the satellite data. It appears to be the largest source of decorrelation in both the satellite data and the IPCC model output.

    http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175/2008JCLI2253.1&ct=1

    http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175/JCLI3611.1

    http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175/JCLI3974.1
     
    Last edited: Mar 14, 2009
  6. Mar 14, 2009 #5
    Or maybe this is what you are looking for:
    http://ams.allenpress.com/perlserv/?request=get-pdf&file=i1520-0442-21-21-5624.pdf
    "Feedbacks are widely considered to be the largest source of uncertainty in determining the sensitivity of the climate system to increasing anthropogenic greenhouse gas concentrations, yet the ability to diagnose them from observations has remained controversial. Here a simple model is used to demonstrate that any nonfeedback source of top-of-atmosphere radiative flux variations can cause temperature variability, which then results in a positive bias in diagnosed feedbacks. This effect is demonstrated with daily random flux variations, as might be caused by stochastic fluctuations in low cloud cover. The daily noise in radiative flux then causes interannual and decadal temperature variations in the model’s 50-m-deep swamp ocean. The amount of bias in the feedbacks diagnosed from time-averaged model output depends upon the size of the nonfeedback flux variability relative to the surface temperature variability, as well as the sign and magnitude of the specified (true) feedback. For model runs producing monthly shortwave flux anomaly and temperature anomaly statistics similar to those measured by satellites, the diagnosed feedbacks have positive biases generally in the range of −0.3 to −0.8 W m−2 K−1. These results suggest that current observational diagnoses of cloud feedback—and possibly other feedbacks—could be significantly biased in the positive direction."
     
  7. Mar 14, 2009 #6
  8. Mar 14, 2009 #7
    Here is a recent study claiming a strong water vapor feedback.

    Between 2003 and 2008, the global-average surface temperature of the Earth varied by 0.6°C. We analyze here the response of tropospheric water vapor to these variations. Height-resolved measurements of specific humidity (q) and relative humidity (RH) are obtained from NASA's satellite-borne Atmospheric Infrared Sounder (AIRS). Over most of the troposphere, q increased with increasing global-average surface temperature, although some regions showed the opposite response. RH increased in some regions and decreased in others, with the global average remaining nearly constant at most altitudes. The water-vapor feedback implied by these observations is strongly positive, with an average magnitude of λ q = 2.04 W/m2/K, similar to that simulated by climate models. The magnitude is similar to that obtained if the atmosphere maintained constant RH everywhere.

    http://www.agu.org/pubs/crossref/2008/2008GL035333.shtml"
     
    Last edited by a moderator: Apr 24, 2017
  9. Mar 15, 2009 #8
    Last edited: Mar 15, 2009
  10. Mar 15, 2009 #9
    Here was Dr. Roy Spencer's answer to Andrew Dressler:
    http://www.drroyspencer.com/2009/02/what-about-the-clouds-andy/
    "I’ve been receiving a lot of questions lately about Andrew Dessler’s water vapor feedback paper which supports the positive water vapor feedback exhibited by the IPCC climate models. Dessler and co-authors used AIRS temperature and humidity sounding retrievals from the Aqua satellite during 2003-2008 to compute how the specific humidity changed with warming"
     
  11. Mar 15, 2009 #10
    No offense Mike, but if I posted this from Dr. Spencer's website I do believe it would be "stricken from the record".

    http://www.drroyspencer.com/2009/02/...e-clouds-andy/" [Broken]

     
    Last edited by a moderator: May 4, 2017
  12. Mar 15, 2009 #11
    WeatherRusty:
    You brought up the Dressler paper and I pointed out a reply.
     
  13. Mar 16, 2009 #12

    Xnn

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    Here is a peer reviewed paper from the National Academy that identifies the human induced increases of atmospheric moisture content:

    http://www.pnas.org/content/104/39/15248.full.pdf+html

    and

    As I understand it, part of the problem is that there is not a lot of agreement between all the various models. After all, there is still a wide range between 2.0 to 4.5 C/doubling of CO2 accepted for climate sensitivity. That said, there is a corresponding differance between what is noise and what is not. What the above study has found is that the increase in moisture content has become significant enough that it can not be just noise.
     
  14. Mar 16, 2009 #13

    Xnn

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    Spencer runs a climate model with a 50m deep swamp instead of oceans.
    He finds that earth observations do not match it and then announces that something must be wrong.

    Like duh; what did he expect?

    Earths oceans are over 3000 m deep and absorb over 90% of the heat of global warming. So obviously, he is modeling the climate of some other planet.
     
  15. Mar 17, 2009 #14

    mheslep

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    Where's this coming from? One of his links above?
     
  16. Mar 24, 2009 #15
    That is not a reply.

    A proper reply would be published in the same journal as the original research article.

    And Spencer also believes Intelligent Design is a valid scientific theory.

    Not a very good authority to appeal to.
     
  17. Mar 24, 2009 #16

    mheslep

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    I don't think so. Appears he is saying he finds the scientific basis for both ID and evolution as weak, with evolution requiring imaginative constructions to cover gaps in the evidence.
    http://www.tcsdaily.com/article.aspx?id=080805I [Broken]
     
    Last edited by a moderator: May 4, 2017
  18. Mar 24, 2009 #17
    Perfect illustration of my point that Roy Spencer is not a very good authority to appeal to.

    He is claiming that evolution is faith based and that is nonsense. He said he used to believe it was a fact. Not very scientific since facts are not theories and theories are far more scientifically valid than facts since they are derived from the interpretation of facts. Facts can be right or wrong without changing the underlying theory.

    The scientific community and the courts have decided that ID is creationism. The strongest evidence being the draft documents and even the final publication where the authors did a search and replace on the word Creator with designer after a court ruling forbid the teaching of creationism in public schools.

    Spencer is not a good authority to appeal to. Even his analysis of the MSU data (his area of expertise) is the outlier among all the other global temperature records.
     
  19. Mar 24, 2009 #18
    Skyhumter:
    Actually everything in life is faith based. Ask any philosopher. I see no reason to not rely on Spencer. The issue is water vapor feedbacks and that seems to be an area he is concerned about and has published papers about.

    Do you have papers that falsify his theory or just disagree? Disagreement is called debate and I was lead to believe that is how science advances. Unless science has changed recently.
     
  20. Mar 25, 2009 #19
    That is a logical fallacy known as http://en.wikipedia.org/wiki/Poisoning_the_well" [Broken]

    The Spencer link provided was not about his published research or proposed theories. It was his opinion being masqueraded as a scientific critique. A real critique would be published in the same journal, not on a blog site.

    If you wish to discuss his theory about how the water cycle acts as a thermostat to limit global warming, first provide a link to his published research.
     
    Last edited by a moderator: May 4, 2017
  21. Mar 25, 2009 #20

    mheslep

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    I've no particular interest in defending Spence but these criticisms don't follow my reading of his statements:
    No, he explicitly acknowledges natural selection in populations due to environmental pressures, he states that Gould's punctuated equilibriums invented to cover the gaps in the fossil record are based not on observations, but on faith.
    He said "fact", in quotes. That's making a bit much of it.
    The scientific 'community' doesn't 'decide'. Scientists prove, or falsify, by train of evidence.
    C'mon, non-sequitur. Has nothing to do w/ statements by Spencer.
     
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