2009 SOI so far refuses tango with El Nino

The large climate groups including NOAA in the USA, are predicting an El Nino event in 2009.

The Australian Bureau of Meteorology (BoM) said on 8 July “Leading climate models indicate that warming of the Pacific will continue for the next few seasons, with very little chance of the current development stalling or reversing.”

It is is noteworthy that the Southern Oscillation Index (SOI) which should be trending towards negative monthly values for an El Nino – still shows a positive 30 day average value of 8.38 as of the 18th July 09. SOI information.

The BoM discuss effects of the “classical” or “canonical” ENSO events since 1900 and I have plotted the month by month SOI numbers showing development of those El Nino events – adding in 2002 and 2006. We can compare 2009 with the series of strong El Nino’s and it is clear that the SOI in 2009 is too positive for us to be expecting a “canonical” El Nino.

2009 SOI compared strong El Nino years

I have put in a nominal 0 value for July but note that as I write the 30 day average at 18th July is 8.56.

So it looks unlikely we will see a “canonical” El Nino start in 2009. But hey !!, we might see a weaker event.

Interesting too that the TAO SST map for the El Nino regions for the 17th July seems to show the anomaly weaker than the BoM inset shows re the 8th.

NOAA TAO SST anomalies

The BoM say their next comment is on 22nd July – it will be interesting to examine the nuances in what they say – in the light of hard data.

16 thoughts on “2009 SOI so far refuses tango with El Nino”

  1. NOAA talks about the same event Ian. They must be betting on a very sharp plunge in the SOI from now on. If that happens and we get a classical El Nino with SOI between -15 and -20 in what’s left of 2009 – then by my graphic it will be a once in a century event – coming so late. Bear in mind my heavy red line should be at +10 now, I have it at zero for July to allow for the SOI to fall in what is left of July.

  2. Thanks WSH.
    Does NOAA provide the sea surface temperatures? I noticed that they claim that June was one of the warmest Junes ever (2nd?). Yet when one looks at their global temp map there seems to be some odd results (ie NSW is shown as 3C above normal for the most part; BOM says less than 2C).
    www.ncdc.noaa.gov/img/climate/research/2009/jun/map-blended-mntp-200906-pg.gif
    It will be interesting to see if your analysis holds (especially if NOAA’s figures are dodgy). Here are some recent comments from the BOM (22nd July).
    ‘ The latest 30-day SOI value is +12, while the monthly value for June was −2. The latest 30-day value is unusual for a developing El Niño; persistent negative values are a feature of El Niño events.’
    ‘Some cooling of the warm waters off northern Australia has occurred in the past week. As the equatorial Pacific continues to warm and Trade Winds remain generally weak the SOI is expected to fall to negative values again.’
    Only time will tell.

  3. You’d probably know better than me-what is the best indicator of ENSO variability? Obviously this post refers to SOI but there are many others-which makes it hard to figure which is the “real” ENSO proxy.

  4. The SOI has the advantage of a reconstruction from 1876. I would be very surprised if we saw a significant El Nino without a prominent negative SOI signal. Note that from mid-July the daily SOI has been oscillating near zero, of little help to the BoM and NOAA predictions. There is a week of strong positive numbers to work out of the 30 day average – so that will very likely keep easing to end July. From the start of August the BoM and NOAA need month after month of strong negative numbers to roll through.

  5. You were v close with your 0 prediction for July SOI. Have you noticed on the TAO SST anomaly map how the yellow +1 cigar shaped anomaly is weakening and a zero contour has come in near PNG.

  6. Great call Warwick.

    At least NOAA’s doing a good job of providing data and sticking their necks out with predictions. It’s great that they explain their thinking about El Nino every week at the first site you reference (under “Weekly ENSO Update”).

    And if you look at their latest weekly update (click on the words pdf or ppt on their page, not the symbols), they would have felt they had good reason to call an El Nino a month ago. In particular, slide 11 shows huge warm water anomalies in the Pacific depths that one could expect to well up to the surface.

    Their other, more elaborate indicators were looking good for El Nino too – wind patterns, outgoing longwave radiation, Madden-Julian oscillation. All very sophisticated stuff.

    Unfortunately they, and their large suite of models, forgot something simple. El Ninos almost always form by July, and the ENSO index (a measure of the difference in atmospheric pressure between Darwin and Tahiti), has to fall regularly for months beforehand. It was falling all right – but the fall didn’t start early enough and hasn’t gone fast enough to produce a decent El Nino.

    The BOM discussion of “canonical” ENSO events that you also reference actually gets very close to realising this. It shows a graph that is in effect the average of the lines on your graph. You can see from it that, on average, the last 12 El Ninos were fully established by July. But your graph is better in that it shows practically every one of them was fully established by July. The only exception is 1991, and that was both pretty weak anyway, and dropped away sharply in August and September. The obvious conclusion is that if we do get an El Nino this year and early next, it is is likely to be weaker than any of the 12 canonicals.

    NOAA’s latest weekly bulletin (10 August) is still calling El Nino conditions through next winter. They say that “A majority of ENSO models indicate El Niño (SST anomalies greater than +0.5°C) will continue to intensify during Northern Hemisphere summer and last through Northern Hemisphere winter 2009-10. The models disagree on the eventual strength of El Niño (+0.5°C to +2.0°C), but nearly all of the dynamical models predict a moderate-to-strong episode.”

    That might happen but I wouldn’t bet on it. The way it looks now it might not even meet the official definition of an El Nino at all – five sucessive three-month averages of more than half a degree over normal in the mid-Pacific. NOAA’s slide 5 shows this measure has already fallen from 0.9 to 0.75 in the last month, and as of today (your TAO SST map) it is not much about zero.

    There’s another NOAA Weekly Update out today. Wonder if they’ll start backing off?

  7. The author’s religion, alleged or otherwise, has nothing to do with the science. And science proves the AGW theory wrong. To bring up the author’s religious beliefs is a standard debate tactic when you can’t refute the facts or science. If you can’t refute the point, refute the presenter.

  8. The Mantua paper elucidating PDO indicated ENSO and PDO have to be in phase for El Nino/La Nina episodes to be climatically efficacious, i.e, NOAA is asleep, dreaming of warming.

    I wonder whether following a long La Nina-with increased cloudiness worldwide in the relative absence of solar input-this is merely a chimeral El Nino: SSTs have risen due to falling cold water.

  9. One of the NOAA people has a more personal discussion of the current El Nino conditions here:

    He (a Mr Klaus Wolter) concludes his latest report (5 August) thus: “We have now entered the time of year when rapid changes of the MEI become less common, and the recent switch to El Niño is now ‘locked in’ for at least several months. This is a major change compared to my assessment a few months ago, but consistent with last month’s discussion that such a big rise in the MEI and such high MEI values as in the last two months have always been followed by continued El Niño conditions through the remainder of the calendar year, at least in the post-1950 MEI record. This does not exclude an early weakening of this event either, in fact, the best ‘analog’ year of 1951 ended up with very weak El Niño conditions by the end of that year.”

    He backs this up with a graph that shows current conditions following a pattern of La Nina’s turning into weak and short-lived El Ninos (i.e. events that just qualify, and most of which are tailing off by December/January).

    Seems a bit odd when NOAA’s official assessment this week still says: “Current observations and dynamical model forecasts indicate El Niño is expected to strengthen and last through Northern Hemisphere winter 2009-10.”

    Meanwhile the TAO/TRITON graph shows the central Pacific warming up a bit again after the cool spell the last couple of weeks. But it’s still less than 1 degree above normal overall and as Gary Gulrud says above, it is not having much effect on climate – the last 90 days of the Southern Oscillation Index, which would be down to minus 15 or 20 in a decent El Nino, is today only at minus 1.

  10. Warwick: I like your method of analysis. But do you implicitly assume that the climate system is stable over time, driven by essentially unchanged basic parameters?

    I have a post at climatechange1.wordpress.com entitled “Wherefore art thou Nino” that looks at the origins of the increase in temperature along the equator in the Pacific and in the global tropics.

    The point that I make in this post is that the driver of Pacific and Tropical Ocean warming in general is changing. That change has been going on for a long time. In particular, the latitude 30-40S in the South East Pacific came into play only in the eighties and has been a strong driver of the temperature of the in-feed waters since that time. Those in-feed waters have been strongly gyrating in temperature over the last few years but the bottom of the troughs are on a strongly ascending trend. Currently cooling, but due to warm again late in the year these waters could pre-warm to the extent where the 2010 winter surge will produce a notable El Nino event.

  11. Thanks for dropping in Erl – you know I have long enjoyed your work.
    The purpose of my post was to simply point out how the big climate groups like NOAA and BoM – spending Billions of our hard earned tax dollars – and major supporters of proposed colossal Govt schemes to reduce carbon emissions – have called El Nino wrong in 2009. My point being, “if they can not call El Nino a few months ahead – how come society is believing what they say re warming several decades into the future.”

  12. I agree it is remarkable to see a media piece not beating up AGW – actually discussing the meteorology. Yet note the BoM media release “Climate records broken” which seems to be from the BoM that we know and love, no talk of meteorology there !! I have a few comments planned.

  13. I’m a keen follower of late-winter weather and rainfall, for various reasons. What amazed me was the fifties-style winters of ’07 and ’08 that hardly rated a mention by MSM. Here on the mid-north coast of NSW we had months of cold, damp southerlies, thunder in august, temp averages only kept up by persistent cloud-cover. To me this was at least interesting and some kind of support for the PDO thesis, yet for many in the media nothing was going on.

    Now we have one very mild winter and you can’t shut ‘em up.

    It seems that what warms is climate, and what cools is weather.

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