ENSO a Natural Oscillation

ENSO Weekly Status.  Temps and Anomalies.

ENSO Weekly Status. Temps and Anomalies.

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This paper:

http://users.monash.edu.au/~dietmard/papers/dommenget.slab.elnino.grl.pdf/

Shows that, at least in a computer model, the ENSO (El Nino Southern Oscillation) can occur all on it’s own as a natural process.

Nice to have that “confirmed” by a model. (Guess it is kind of hard to run an experiment in the real world…)

Abstract

In a series of Atmospheric model simulations coupled to a simple slab ocean model it is illustrated that El Niño type of SST variability can exist in the absence of any ocean dynamics. Atmospheric feedbacks in cloud cover and changes in the wind field can produce positive and delayed negative feedbacks, that together with the heat capacity of the upper ocean can produce a damped interannual oscillation in the equatorial Pacific, that is comparable in strength and has characteristics to the observed phenomenon. The evolution of the SST pattern is similar to the SST-­‐mode of El Niño, but is entirely controlled by atmospheric feedbacks. The results challenge and extend our current understanding of the feedback mechanisms of El Niño in climate models and may also highlight possible atmospheric mechanisms that could partly control some observed ENSO events.

Well, glad all the science was settled about Global Warming before this came out…

Hate to think we’d been running back and forth between a warming 1930’s to a cooling 1960 and back to a warming 1990’s all as a natural 60 year cycle with no need at all for CO2 in the process…

(For the inevitable slow to think it through critics: Yes, the PDO is not the ENSO. But if ENSO is a natural emergent behaviour then the long term impacts of a similar process can manifest as a similar though longer term shift, the PDO.)

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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7 Responses to ENSO a Natural Oscillation

  1. Just thought I’d mention that ENSO has a *major* effect on Australia! We are having a really wet 12 months starting last December. Before Dec 09 the dams were getting very low/empty with less than half the normal annual rainfall for a decade. Most state Governments here have ordered Desalination Plants – very expensive and inappropriate IMHO.
    Untill the rains started the drought was ‘due to AGW’

    I was listening to a fellow who was managing a large Australian sheep farm with daily weather records spanning 120 years. He said there was a notebook for each year, and at the back of each book was a summary sentence. The most common summary was “This has been a most unusual year.”

    I think that sums up the situation nicely ;)

  2. Baa Humbug says:

    In a series of Atmospheric model simulations coupled to a simple slab ocean model it is illustrated that El Niño type of SST variability can exist in the absence of any ocean dynamics.

    I dare the authors to make that statement to Bob Tisdales face.

  3. Bob Tisdale says:

    Baa Humbug: In the real world, though, the ocean exists and isn’t removed/removable.

  4. tallbloke says:

    As Bob Tisdale has shown, during warming phases, El Nino causes upward step changes in global surface temp. The energy has to come from somewhere to do this, and it comes of the oceans. If the heat content of the oceans is still rising after an El nino, then the energy in the oceans is being topped up from somewhere else. That somewhere else is the sun.

  5. Laurence M. Sheehan says:

    Certainly, there appear to be oscillations, but the amplitudes and frequencies never match. The same sort phenomenon can be seen tracking a roulette wheel, periods where black can appear to seem to be oscillating with red, or one dominating the other for a while, then reversing in seeming oscillation.

    As quantum physics “says”, it may all be a matter of probability. Just like weather. And we know not the boundries of the outliers.

    Theory of probability and the nature of random distributions. We really know little from an accuracy standpoint, as far as history or proxies go.

    From what I have observed, what happened in the past can not be used to predict the future, from a weather or climate standpoint.

    Too, we should be stating temperatures in degrees Kelvin, if calculating a percentage of change.

  6. Tim Clark says:

    simple slab ocean model

    What the heck is that? How thick a slab?

    Atmospheric feedbacks in cloud cover and changes in the wind field can produce positive and delayed negative feedbacks.

    Same old, same old. Chicken and egg scenario.

  7. Pascvaks says:

    We really should be much relieved that they didn’t come to the conclusion that ENSO was ‘un-natural’. In this day and age, it wouldn’t have surprised me if they had. Computers can do anything. Really!

    (OK! NOT everything. But they’re working on it;-)

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