Ian Wilson: Is the November 2018 Madden Julian Oscillation (MJO) a possible trigger for an El Niño?

Posted: November 20, 2018 by oldbrew in climate, ENSO, research

Conservation of angular momentum – ice skater


The title says it all. Another in the author’s series of intriguing brain-teasers for followers of climate theory to explore, this time with a particularly topical theme.

1. The Madden Julian Oscillation (MJO)

The Madden Julian Oscillation (MJO) is the dominant form of intra-seasonal (30 to 90 days) atmospheric variability in the Earth’s equatorial regions (Zang 2005). It is characterized by the eastward progression of a large region of enhanced convection and rainfall that is centered upon the Equator.

This region of enhanced precipitation is followed by an equally large region of suppressed convection and rainfall. The precipitation pattern takes about 30 – 60 days to complete one cycle, when seen from a given point along the equator (Madden and Julian 1971, 1972).

At the start of the enhanced convection phase of an MJO, a large region of greater than normal rainfall forms in the far western Indian Ocean and then propagates in an easterly direction along the equator.

This region of enhanced rainfall travels at a speed of ~ 5 m/sec across the Indian Ocean, the Indonesian Archipelago (i.e. the Maritime Continent) and on into the western Pacific Ocean. However, once it reaches the central Pacific Ocean, it speeds up to ~ 15 m/sec and weakens as it moves out over the cooler ocean waters of the eastern Pacific.

Wheeler and Hendon (2004) have developed a Real-time Multivariate MJO (RMM) Index that tracks the strength and movement of the enhanced-convection phase of MJOs.

This index is based upon the first two Empirical Orthogonal Functions (EOFs) of the combined fields of the equatorially averaged (15°S to 15°N) outgoing longwave radiation (OLR), 850 hPa zonal wind and 200 hPa zonal wind data for the period from 1979 to 2001.

Continued here.

Comments
  1. oldbrew says:

    Wikipedia offers some support to IW’s line of thinking.

    In the Pacific, strong MJO activity is often observed 6 – 12 months prior to the onset of an El Niño episode

    Read more: https://en.wikipedia.org/wiki/Madden%E2%80%93Julian_oscillation#Link_to_the_El_Nino-Southern_oscillation
    – – –
    El Niño and solar cycle prediction are two of the trickiest problems in the climate realm.

  2. cognog2 says:

    I find this fascinating; for I have long held the view that lunar/solar/tidal influences in the atmosphere must reflect in the wind and the hydro cycle, due to the barometric pressure changes involved. The latter being the resulting change in the temperature at which phase change takes place. However it never occurred to me that the conservation of angular momentum could be involved. The 30 to 60 day period appears to have synergy with the tides.

    But Oh Dear! the complexities and nuances are daunting. Seems in lateral thinking terms that there is a heart beating somewhere.

  3. oldbrew says:

    From the Australian BoM’s new ENSO outlook issued today:

    The ENSO Outlook remains at El Niño ALERT. This means the chance of El Niño forming in 2018 is around 70%; triple the normal likelihood.

    Temperatures in the tropical Pacific Ocean remain above El Niño thresholds, but atmospheric indicators have yet to show a consistent El Niño signal and are presently neutral. This suggests the tropical Pacific atmosphere and ocean have yet to couple (reinforce each other), a process that would sustain an El Niño, and result in widespread global impacts. Model outlooks indicate that sea surface temperatures in the tropical Pacific are likely to remain above El Niño thresholds in the coming months.

    El Niño ALERT is not a guarantee that El Niño will occur; it is an indication that most typical precursors of an event are in place. If an El Niño were to develop, it would be considered a very late starting event.

    http://www.bom.gov.au/climate/enso/outlook/

    [NB this is overwritten every two weeks. Next issue 4 December 2018]

  4. oldbrew says:

    A brief look at the MJO and its likely effects, from the Indian Express – aimed at general readers.

    https://indianexpress.com/article/explained/madden-julian-oscillation-the-reason-behind-the-unexpectedly-good-june-rainfall/

  5. Salvatore Del Prete says:

    In my opinion they can not predict El Nino.

  6. oldbrew says:

    Yes, no, maybe…?

    EL NIÑO SIGNAL WEAKENS
    Date: 20/11/18 Reuters

    El Niño signal weakened again with sea surface temps in central-eastern Pacific +0.7C above long-term average down from +1.2C two weeks prior

    https://www.thegwpf.com/el-nino-signal-weakens/

  7. Salvatore Del Prete says:

    astro climatelink – but you predict no EL NINO of any sort this winter?

  8. FYI here is a link for this week analysis for MJO and ENSO at Stormsurf. The analysis of MJO and ENSO start at 13:30 into the video. https://youtu.be/dBu-GtwokA4

  9. Shaun says:

    Hi Ian, this is interesting. In your chart of deviation of length of day I notice that the slowest points at the equatorial crossing are quite different in the same month. I presume this is to do with the height of the tide being different for these two times. Is there a convenient source for the angular momentum so that I could construct such a chart on an ongoing basis?
    I ask because it might help me refine a rough forecasting method which appears to work at the location of my farm in Tasmania, where rain, if it comes at all, often seems to coincide with the moon crossing the equator from north to south.

  10. Shaun says:

    Actually I think I should have said angular velocity not momentum, which is of course constant.

  11. oldbrew says:

    Well-known warmist frothing already…

    Another El Niño is nearly upon us. What does that mean?
    By Eric Holthaus on Nov 21, 2018

    A new El Niño is brewing in the tropical Pacific, threatening an uptick in global temperatures and extreme weather.

    https://grist.org/article/another-el-nino-is-nearly-upon-us-what-does-that-mean/

  12. Shaun says:

    Excellent, thanks Ian.

  13. Brett Keane says:

    For the last 3yrs I have been riding my own horse on Enso matters. As I/we predicted tentatively, the last two Ninos have fizzled, aborted for lack of energy. We put it down to the Quiet Sun ie lack of HF sunlight UV etc..
    But we make no claims of certainty yet, data is incomplete as usual so only Empirics lead us for now……. Brett

  14. Brett Keane says:

    Astro, my guess is that we have seen that period and are now starting a cooler regime. AMOC is overturning too, something the warmista have ignored but cannot control…… The loopy vortices, North and South Polar, are bringing the viciousness, noticeably right now. Brett

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