JoNova website...posted May 2nd, 2010:
The La Nina shark rises to bite --animation
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Does this herald the end of this years warm spell?
Frank Lansner has been watching the Southern Oscillation Index and noticed it’s rapid climb out of El Nino territory. He’s found graphs showing how the warm water is displaced from below and I’ve pasted them into a brutally rough animation.
See Franks full post
I wouldn’t use a single season to debunk AGW (and nor does Frank) but we all know that the crowds are swayed by weather, and Frank’s point is that the weather is possibly not going to help The Big Scare Campaign.
McLean, De Frietas, and Carter published a paper last year pointing out how much influence the La-Nina-El-Nino system has on the global climate. In an El Nino, the surface of the Pacific doesn’t churn as much because there is not as much wind, and so warm waters stay on the top and satellites record high temperatures. But in a La Nina the winds resume, surface mixing increases, deep cold waters from below displace the warmer water on top, and so the ocean surface cools.
If you’ve wondered why, during the 1998 El Nino, the satellite records “spiked” up so high compared to the surface records, it’s because of the influence of ocean temperatures. Satellites measure the surface temperature of the planet, and 70% of the surface is ocean. So when warm water is “stalled” on the surface, it shows up in the satellite records. But deep down, the oceans presumably are not getting that warming effect (or at least it is delayed).
There is roughly a 5-7 month lag between the SOI and global temperatures.
John McLean makes a guesstimate on the run (from an airport lounge):
I think UAH LTT’s [lower trophosphere satellite measurements of temperature] will remain on the high side until around October then a cooling off. Maybe we’re looking at another cold northern winter at year’s end.
Thanks to William Kininmonth for advice (over the last year), and Frank Lansner for his work
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UPDATE: There’s become quite a debate about the likelihood of a La Nina.