Claim: Greenhouse gases reduce Walker Circulation

From the UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE and the “correlation is not causation department” comes this paper that suggests GHG’s decrease the Walker Circulation. Only one problem. They don’t give a clear cut mechanism, only tenuous linkage. I suspect Willis will have a thing or two to say about this paper.

Study of cloud cover in tropical Pacific reveals future climate changes

UM Rosenstiel School researchers find new evidence for weakening of Walker circulation

Walker Circulation is illustrated. CREDIT NOAA Climate.gov

Walker Circulation is illustrated. CREDIT NOAA Climate.gov

MIAMI – A new analysis using changes in cloud cover over the tropical Indo-Pacific Ocean showed that a weakening of a major atmospheric circulation system over the last century is due, in part, to increased greenhouse gas emissions. The findings from researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science provide new evidence that climate change in the tropical Pacific will result in changes in rainfall patterns in the region and amplify warming near the equator in the future.

“Our findings show that an increasing concentration of greenhouse gases leads to significant changes in atmospheric circulation and tropical rainfall patterns,” said Katinka Bellomo, an alumna of the UM Rosenstiel School. “This study demonstrates that we can predict these changes in the Walker circulation from changes in cloud cover.”

The UM Rosenstiel School researchers used historical observations of cloud cover as a proxy for wind velocity in climate models to analyze the Walker circulation, the atmospheric air flow and heat distribution in the tropic Pacific region that affects patterns of tropical rainfall. Their findings revealed a weakening and eastward shift of the Walker circulation over the last century due to greenhouse gas emissions. The analysis showed that changes in cloud cover can serve as a proxy in climate models for wind velocity in the atmosphere, which cannot be directly measured.

“This study makes innovative use of a decades old-dataset,” said Amy Clement, professor of atmospheric science at the UM Rosenstiel School. “It is impressive that visual observations from the decks of ships transiting the Pacific Ocean over a half-century can tell us something so fundamental about climate change.”

This new information can be incorporated into current climate models to predict future changes in the magnitude and pattern of the Walker Circulation due to increased greenhouse gas emissions. The study suggests that rainfall will decrease over Indonesia and in the western Pacific and increase over the central Pacific Ocean.

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The study, titled “Evidence for weakening of the Walker circulation from cloud observations,” was published in the journal Geophysical Research Letters. The study’s authors include: Katinka Bellomo and Amy C. Clement of the UM Rosenstiel School. The work was supported by grants from National Science Foundation Climate and Large Scaled Dynamics, National Oceanic and Atmospheric Administration’s Climate Program Office, grant # NA10OAR4310204 and Department of Energy Biological and Environmental Research, grant #DESC0004897.

The publication can be accessed here: http://onlinelibrary.wiley.com/doi/10.1002/2015GL065463/abstract (Paywalled)

Abstract

Climate models simulate a weakening of the Walker circulation in response to increased greenhouse gases, but it has not been possible to detect this weakening with observations because there are not direct measurements of atmospheric circulation strength. Indirect measurements, such as equatorial gradients in sea level pressure (SLP), exhibit trends of inconsistent sign. In this study we estimate the change in midtropospheric velocity (ω500) from observed change in cloud cover, which we argue is more closely tied to the overturning circulation than indirect measurements of SLP at the surface. Our estimates suggest a weakening and eastward shift of the Walker circulation over the last century. Because changes in cloud cover in Atmospheric Model Intercomparison Project simulations forced with increased sea surface temperature are remarkably similar in pattern, sign, and magnitude, we assert that the observed changes in cloud cover and the associated weakening of Walker circulation are at least in part externally forced.

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37 thoughts on “Claim: Greenhouse gases reduce Walker Circulation

  1. Correlation does not equal causation – the weakening of the Walker circulation just MAY be due to other factors!!!!!!!!!!

    • Too bad these folks are spewing all this speculation as if it were empirical, which when proven false will damage their credibility in the science community.

  2. “This study makes innovative use of a decades old dataset ”
    Isn’t “Climate scientists ” getting “innovative ” with datasets the primary problem?

      • That was the phrase that jumped out to me as well, when you see something being used in an “innovative” way it means it is being used in way that it was not designed to be used
        James Bull

  3. A new analysis using changes in cloud cover over the tropical Indo-Pacific Ocean showed that a weakening of a major atmospheric circulation system over the last century is due………..Our estimates suggest a weakening and eastward shift of the Walker circulation over the last century.
    …………“This study makes innovative use of a decades old-dataset,” said Amy Clement, professor of atmospheric science at the UM Rosenstiel School. “It is impressive that visual observations from the decks of ships transiting the Pacific Ocean over a half-century
    I hate it when they do this

    • In AMIP, Walker is not interwoven with ENSO and PDO because there is no ocean-atmosphere feedback. Add a second bogus meter to measure the magnitude of bogus meter pegging.

  4. Chicken, egg, horse and cart modelled to perfection. Walker becomes runner circulation sprinting toward Parisian finish line.

  5. 1 – Climate models simulate a weakening of the Walker circulation in response to increased greenhouse gases
    2 – not been possible to detect this weakening with observations because there are not direct measurements of atmospheric circulation strength.
    3 – Indirect measurements, such as equatorial gradients in sea level pressure (SLP), exhibit trends of inconsistent sign.
    4 – Because changes in cloud cover in Atmospheric Model Intercomparison Project simulations forced with increased sea surface temperature
    5 – we assert that the observed changes in cloud cover and the associated weakening of Walker circulation are at least in part externally forced.

    1 -Since the models do not get anything right, why do you think they get Walker circulation right?
    2 -Could this also be because there is no weakening (until your assertion).
    3 -Trend in inconsistent sign? You mean “like Walker circulation is increasing?”
    4 -So they forced the model, to get an increase in temperature, stimulate a weakening, go search for any sign it could happen. Bill Engvall – “Here’s Your Sign” already copyrighted that.
    5 -We assert our computer is externally forced by our programmers.

  6. Assume that the Walker circulation is weakening, thereby pushing the tropical evapotranspiration upwelling farther to the east. What implication does that have for the western and southwestern US? Wouldn’t the semi-perpetual high pressure resulting from all the sinking air upon its downward return shift desert-like dryness father east as well? Would that explain the Dustbowl of the 1930’s, and would it portend a much wetter California/Great Basin/Sonoran Desert region?

  7. So they can’t measure something in the real world, take some data which might be related into partial climate models. They tinker with the climate models and get a result which they expected, and use that to claim proof of a change which must be made to climate models. Worse, their “result” is because several climate models agreed with other climate models, and if climate models agree with each other then reality must work the same way.
    I need to convert more meteorological instruments into drinking implements.

  8. Ah hahaha oh my god the cloud observations from the freaking ship tracks? Really? Do they have any idea how unreliable that kind of thing is going back a century?.
    Of course they do. But “I can’t find this effect in a relatively reliable dataset, so let’s try an unreliable one instead!” is standard fare by now in Climate Science (TM)

    • Like tossing out readings from buoys and replacing them with readings from shipboard water intakes. Whatever database shows the result you are looking for, must be the accurate one.

  9. I presume this paper was peer reviewed – those “peers” are equally to blame. No wonder they wish to remain anonymous.

  10. “The UM Rosenstiel School researchers used historical observations of cloud cover as a proxy for wind velocity in climate models to analyze the Walker circulation…”
    Proxy? Is there no actual wind data available? What relationship was used; more clouds with more wind or vice versa? I believe the normal understanding is that low atmosphere pressure (measured with barometers and such) leads to high winds, and vice versa. Yet they cannot find a way to make their model work with that generally accepted principle, so they use some eyeball data and get it to fit. Hmm.
    Willis, Help!

  11. “In Science, when we understand a system, we can predict its behavior. If not, we do not understand the system.”-John Christy
    “Abstract:
    Climate models simulate a weakening of the Walker circulation in response to increased greenhouse gases, but it has not been possible to detect this weakening with observations …” -Katinka Bellomo and Amy C. Clement
    Another admission that these models have no predictive ability. But let’s go ahead and use broken models to implement world policy. (Evil laughter now: Bwa ha ha ha…) Let’s all meet in Paris and take another crack at breaking open that big carbon money bomb.

  12. 2 things: First I would like a little more evidence that the proxies they chose are actually valid proxies.
    Second, I love the way they assume that since something has changed, it must be caused by CO2 changes. After all, we have already proven that nothing else has changed, anywhere in the world over the last 100 years, haven’t we?

  13. “It is impressive that visual observations from the decks of ships transiting the Pacific Ocean over a half-century can tell us something so fundamental about climate change.”
    In this instance I would have gone with “impossible” rather than impressive.

  14. Abstract
    Climate models simulate a weakening of the Walker circulation in response to increased greenhouse gases, but it has not been possible to detect this weakening with observations because there are not direct measurements of atmospheric circulation strength.

    Translation: “We studied The Big Rock Candy Mountain and here are our results.”
    (Link to the song: “Big Rock Candy Mountain”)
    http://www.metrolyrics.com/big-rock-candy-mountain-lyrics-harry-mcclintock.html

  15. So, they/we are to accept conclusions based on ships 100 years ago recording their correct latitude, longitude, and cloud conditions? And, doing so reliably under any sea or weather conditions so as not to insert bias in one way or another? (Besides relating it directly to how the Walker Circulation might change…)
    OUTSTANDING!
    /snark
    I once analyzed some of these reports in college. We found that some of those 100 year old ship reports claimed to be from the middle of the Sahara…and others where the water temperatures were well below freezing.

    • Am I seeing this correctly, they “used historical observations of cloud cover as a proxy for wind velocity in climate models to analyze the Walker circulation”? This, so called, data is from older ship deck level observation that were probably ships that were slower than some of the frontal systems they may have observed?
      Next they will be using old ship engine intake temp records instead of the precise ARGO data. Oh wait,,,,, they already did that…..
      .http://judithcurry.com/2015/06/04/has-noaa-busted-the-pause-in-global-warming/

  16. So these models show a weakening Walker Circulation in the tropics with less clouds, more sunshine, and more heat. I assume these are the same models that show a runaway heating from water vapor feedback. So, more water vapor and less clouds are in the tarot cards, it’s unprecedentedly worse than we thought.

  17. Didn’t think it would take long for them try to blame CO2 on El Ninos again because they have already tried to blame CO2 on everything else there is on the planet. It has been becoming too obvious that ENSO is too much involved in the main swing of global temperatures, with decreasing cloud cover and increased SW radiation. CO2 has absolutely nothing to do with the Walker circulation because it does not reduce water vapor in the atmosphere. In fact there is no sign CO2 has any affect on water vapor at all in the atmosphere on land or the ocean. Water vapor has been increasing over ocean with ENSO, but decreasing over land. A recent study from the reanalysis project showed the Walker Circulation had not changed.
    Models means absolutely nothing until real observations show the same thing for x number of years.
    The Walker circulation is caused by the pressure gradient force that results from a high pressure system over the eastern Pacific ocean, and a low pressure system over Indonesia. When the Walker circulation weakens or reverses, an El Niño results, causing the ocean surface to be warmer than average, as upwelling of cold water occurs less or not at all. An especially strong Walker circulation causes a La Niña, resulting in cooler ocean temperatures due to increased upwelling.

    A scientific study published in May 2006 in the journal Nature indicates that the Walker circulation has been slowing since the mid-19th Century. The authors argue that global warming is a likely causative factor in the weakening of the wind pattern. However, a new study from The Twentieth Century Reanalysis Project shows that the Walker circulation has not been slowing (or increasing) from 1871-2008.

    • Climate models simulate a weakening of the Walker circulation in response to increased greenhouse gases, but it has not been possible to detect this weakening with observations because there are not direct measurements of atmospheric circulation strength.

      ENSO is the direct result of the atmospheric circulation strength, but during only one PDO cycle you can’t blame this trend from anything other than a change from negative PDO to the recent positive PDO.

  18. Well, since neither Willis nor Bob Tisdale has commented, I’ll have a third string go.
    The walker circulation has implications for “westerly wind bursts”, the “quasi biennial oscillation”, and the “southern oscillation index”. Supply your own acronyms as needed.
    All of these are ENSO indices. (Acronym supplied)
    Are they arguing that greenhouse gasses reduce ENSO?
    The paleo data is ambiguous.

  19. Yes, according to the climatistas it must be because of greenhouse because they can’t think of anything else.
    I who has identified the main drives of ENSO have another explanation. ENSO is affected by changes in the Earth’s magnetic field and by changes in the solar wind.
    When these solar variables are strong the trade wind is weaker and there are more and stronger El Niños. Weaker solar activity has the opposite effect.

  20. When these solar variables are strong the trade wind is weaker and there are more and stronger El Niños. Weaker solar activity has the opposite effect

    Don’t you mean the other way round?
    The behavior of ENSO since the 1950’s shows correlation between weakening solar activity and increased El Ninos. There are also numerous papers on weak El Nino’s during MWP and strong El Nino’s during numerous ice ages or glaciation periods like the YD.

    • You may have a point. During El Niños, Earth loses more heat through outgoing radiation and during La Niñas the Earth gain more heat accumulation in the Oceans. What I have looked at is what has happened during recent decades. Anyway, it’s the Sun, nothing to do with GHG.

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