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The SOI this month

Discussion in 'Alpine & Southern' started by Gimble, Jun 4, 2007.

  1. Gimble

    Gimble First Runs

    Jun 1, 2006
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    Sorry if this is being discussed elsewhere, I couldn't see a thread on it. It's been a while since we had some discussion on the SOI and the latest report is out, so I figured I'd start a thread.

    I don't have a whole lot to say myself, since I don't fully understand it all, but I like to see what you guys think.
    #1 Gimble, Jun 4, 2007
    Last edited by a moderator: Nov 25, 2013
  2. keefy

    keefy First Runs

    Jan 28, 2003
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    A nuetral SOI ( + or - 2 to 3) in a "normal" climate would provide a predictable rain pattern across eastern Australia. However for "drought breaking" rains it is accepted that a very positive SOI should be seen for a number of months, even over a period of a year with moderation to a more nuetral pattern for another few years. However the current climate has tended to display a more negative tendancy for longer periods of time, thus drying out any sustainable rain periods in Eastern Australia... perhaps others could correct me, but I think the La Nina events are around the one in five, therefore we would need to NOT be in an El Nino for very long, to maintain an average rainfall pattern.

    From my prospective, the longer it takes for us to enter into a La Nina pattern, IMHO, the less chance of it actually occuring, based on my 20 years in Australia. Although I do recall the last La Nina event back somewhere in the late eighties early nineties, I do not recall any saturating rains apart from isolated pockets since then.

    The clues for a La Nina or El Nino event are in the Western Pacific, just off the Central and South America's. Although I haven't checked in the last week or so, I recall I was not impressed with the temperature declines, they did not seem to me to be inline with a long term ocean cooling scenario in the Western Pacific waters. The counterbalance to this is a warming of the waters between the Indian ocean and Central pacific to the north of our tropics, the latter seemed to be well underway the last time I checked (a couple of weeks ago)

    Others can throw more and better researched data than I could
  3. Vermillion

    Vermillion Pool Room Ski Pass: Gold

    Nov 13, 2005
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    Cranhole, Melbourne, VIC
    SSTs seem good to me [​IMG] nice and cool in the east pacific. indonesia is in the western pacific :p
    #3 Vermillion, Jun 4, 2007
    Last edited by a moderator: Nov 11, 2013
  4. Gerg

    Gerg One of Us

    Sep 8, 2001
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    There are other effects.

    The monthly SOI goes up and down with the Madden-Julian oscillation , so you need to look at the general SOI trend or at the actual SST's - not just a single month's figure.

    Then there's the PDO (or IPO). I gather that one has been in dry phase for us for the last decade or more, but just might be turning now? Our climate seems to depend on the combined status of ENSO (SOI) and IPO, rather than ENSO by itself.

    Probably there are still other "cycles" or quasi-cycles that significantly affect us.
    #4 Gerg, Jun 5, 2007
    Last edited by a moderator: Nov 14, 2013