Wednesday, November 19, 2014

ENSO Wrap up - El Niño Alert

Sou | 2:55 AM Go to the first of 12 comments. Add a comment

The Australian Bureau of Meteorology (BoM) has shifted its ENSO status to alert, meaning there's a 70% chance or greater of an El Niño. I've updated the sidebar with the latest announcement (pdf version) from BoM.
The Pacific Ocean has shown some renewed signs of El Niño development in recent weeks. Above-average temperatures in the tropical Pacific Ocean have warmed further in the past fortnight, while the Southern Oscillation Index (SOI) has generally been in excess of El Niño thresholds for the past three months. Climate models suggest current conditions will either persist or strengthen. These factors mean the Bureau's ENSO Tracker Status has been upgraded from WATCH to ALERT level, indicating at least a 70% chance of El Niño occurring.
Not all indicators have shifted towards El Niño. Tropical cloudiness near the Date Line and trade wind strength are close to average, suggesting the atmosphere is still not firmly linked with the warmer ocean below. However, trade winds have weakened several times over the past few months and SOI values have remained generally negative, suggesting at least some atmospheric response to the underlying ocean conditions.
International climate models expect the warm tropical Pacific Ocean temperatures to persist, with most models predicting values will remain near or beyond El Niño thresholds for the next two to three months. Regardless of whether or not El Niño fully develops, warmer-than-average tropical Pacific Ocean temperatures, combined with cooler waters currently to the north of Australia increase the chance of some El Niño-like impacts. For many parts of Australia, this suggests below average rainfall and above average temperatures in the months ahead (as shown by the November–January Climate Outlook).

Here are the POAMA model projections - it doesn't look as if it will be earth shattering if it does eventuate. As always, click the image to enlarge it:

Source: BoM

This is what the monthly sea surface temperature anomalies for October looked like:

Source: BoM

And here's a comparison of sub-sea surface temperatures with earlier in the year:

Source: BoM

The updates come out every fortnight. Here is a link to pdf files of the current and past updates.

If you want to learn more about ENSO, this is probably the most extensive article I've written, and it has lots of links so you can explore further.


Millicent said...

An El Nino? Good heavens, that means the law of conservation of energy ceases to operate for a while - another useful 'fact' we learnt at WUWT.

Joe said...

Haha! What does Bob call it? chaotic charge-discharge oscillator? Except he claims the sun does the charging while TSI has been declining for decades. So it's more like a discharge non-oscillator, lol. Or...AGW

David R said...

Until recently at WUWT, Bob Tisdale spent a lot of time playing down the possibility of an El Nino in 2014.

More recently he seemed to switch track and started to look for El Ninos where none have yet been declared.

Possibly it has dawned on Bob that insisting there's no El Nino in 2014 while it turns out to be the warmest year on record is a bad look for his view that warming is caused by El Ninos.

Sou said...

In his latest article, Bob was poking fun at "alarmists" for talking up an El Nino earlier in the year. Which was weird coming from him, because if anyone was making a big deal of the topic it was Bob Tisdale. He wrote that snide comment in his twentieth article about how an El Nino might be coming - or not.

I kid you not. He's written twenty (20) articles about this possible El Nino.

His article even had the title: "The 2014/15 El Niño – Part 20 – November Update – The Little El Niño That Shoulda’-Woulda’-Coulda’"

JCH said...

The last ONI was +0.02.

Say 2014 stays warm and it either ties or eclipses 2010 as the warmest year. And say 2015 starts off with either an EL Nino or several reporting periods of positive ONI. What you would have is the potential for back-to-back warmest years. Lol. The pain.

JCH said...


Harry Twinotter said...

It still looks like the El Nino will be weak. So not catastrophic warming 2014-2015 hopefully. I would hate to see a 1998-type El Nino on top of the 2014 record global average temperatures.

Jammy Dodger said...

Obviously it would not be good news and no-one wants it to happen but it is likely to happen eventually. Perhaps it would be better if it happened earlier rather than later where the variables combined to give a hot year which might make it clearer what is happening to everyone. Then there might be some political will generated.

James D said...

What causes the El Nino effect? Where can I find this out?

Sou said...

The link at the bottom of the above article explains the mechanisms to some extent. Here's a direct link to the main section. The article has links to other sources of information.

ENSO a natural expression of the dynamics of the atmosphere and oceans, like other oscillating patterns such as the longer-lasting Pacific Decadal Oscillation, the Interdecadal Pacific Oscillation and other patterns that scientists see repeating over time.

I'm not suggesting ENSO events and the PDO and IPO are the brought about by the same mechanisms, they aren't. They are similar only in that they all seem to repeat. That is, in all three cases, similar (though not identical) patterns are seen to recur over time. In other wordws, a new La Nina has many similarities with a previous La Nina. One warm phase of the PDO has similarities with another warm phase of the PDO.

James D said...

Thank you - that's most helpful. It's a bit disappointing that ENSO events seem to be rather hard to predict.

Sou said...

It would be nice to predict an event with a bit more warning. On the other hand, the nature of these events and their duration means there's usually sufficient info far enough ahead for farmers to plan what crops and pastures to sow, and for utility companies (water and electricity in particular) to plan for dry or wet. And for ordinary people to decide whether it's time to finally get that rainwater tank installed :)

It's not perfect, but it's a lot better than it used to be.