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The SOI still rules

Who would have thought that if you knew the air pressure in Darwin and Tahiti in June, you could figure out that the start of 2011 might be a Stalingrad Winter up North and a cooler wetter summer down south (Not that people in Sydney feel all that cool right now). But the air pressure ratios are reported as the SOI (Southern Oscillation Index) and it’s the handiest thing if you like predicting global temperatures 7 months ahead. Look at that correlation.

Since June last year Bryan Leyland has been using the simple connection described by Carter, De Freitas, and  McLean in 2009 to predict up and coming temperatures.

So far, for what it’s worth, he’s right on track.


Such is the power of the stored pool of cold that is the bottom three-quarters of the Pacific Ocean. And when you look at how vast the Southern Pacific ocean is, is it any wonder it has such an influence? All that heat capacity…

The Pacific Ocean from space. This is a "full-disk" image of the Earth taken from the GOES-11 satellite at 8 a.m. EDT on Aug. 12. Credit: NASA/GOES Project

As far as records go, the Australian BOM has a list of monthly figures on the SOI chart: The 27.1 recorded in December 2010 was one of the highest readings since records began in 1876.

Bryan Leylands original post: Is the cold weather coming?

The first report of results: Laptop beats Met Supercomputer: SOI index (at record high) scores a win.

A summary of the role the oceans play: The deep oceans drive the atmosphere

David Archibald wrote about the SOI on WUWT in early Dec 2010. This is the full history (as known) of the SOI. Scoring a “27” is a five months-in-a-century type event. (This graph was obviously done before the SOI figure for December was released).


The SOI may be linked to the solar cycle length. Paul Vaughan suggests the Earths rotational velocity is correlated with the solar cycle and with Atlantic oscillations.” Scientists characterize Earth rotation velocity using a variable they call length of day (LOD). The rate of change of LOD (LOD’) is related to global average wind patterns. Changes in wind patterns affect temperature patterns.”

The graph below implies a correlation. If the solar cycle length influenced cloud cover (as per Svensmark) that would also change heating and cooling patterns on the surface of the oceans. That then potentially could shift currents (gradually). Would that then tweak the Length of Day (in nano second amounts)?

LOD = Length of Day, AMO = Atlantic Multidecadal Oscillation, SCL = Solar Cycle Length.

solar cycle length, earth rotational velocity, SOI, AMO, PDO

Click to enlarge

Random post note on the Perth Fires:

Unconnected (as far as I know) with the SOI are the devastating Perth bush-fires. 64 houses lost and in the fringe of suburbia. See the devastation here. No doubt, it will be added to the Evil-Caused-by-Global-Warming litany. Significantly most photos of burnt shells of houses have bush growing right up to the roofline. Strangely in the photos (perhaps it’s just chance) — quite often the trees were spared. I’ll save my thoughts on causes for when there is more information.

Yet again, my heart goes out to the poor souls who have lost everything.

UPDATE: Green policies once again set us up for disaster. According to one fire expert there had been little back burning over the last 15 years and the Perth Hills were and are a tinderbox. The worst fire was due to a man using an angle grinder during a total fire ban. This photo is typical of those suburbs “living in the bush”.

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