Sunday, April 13, 2014

The Coming El Nino and Surface Temperatures

So if the coming (probably) El Nino peaks with a Nino3.4 sea surface temperature anomaly of about 0.8-1.0°C, as NOAA's models are currently projecting (on average), what might that mean for the peak in surface temperature?

Recent history doens't offer much help. Below are the peak surface temperature anomalies (Cowtan & Way dataset) plotted as a function of peak Nino3.4 SSTAs I plotted yesterday.

There's no correlation. Some recent El Ninos have caused even warmer surface temperatures than did the monster 1997-98 El Nino, even though the surface water in the equatorial Pacific never got as warm.

But some did not.

And of those that did, both (2007 and 2010), the latter happened despite the Pacific ocean being in the negative (cold) phase of the PDO.

So the current cold phase might not matter, as some have speculated.

But there is somewhat of a correlation between peak UAH lower tropospheric temperatures as a function of  peak Nino3.4 temperatures:

which is a little surprising, but the correlation between surface temperatures and lower tropospheric temperatures is not perfect (especially, it seems, after El Ninos):

(The correlation is only slightly better (R2 = 0.72) for a 1-month lag, and it degrades with higher lags after that.)

So again, it look iffy to guess what the coming El Nino might bring to atmospheric warming.

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