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Author Topic: Climate Shift?  (Read 1363 times)

Michael Hauber

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Climate Shift?
« on: August 26, 2014, 12:41:44 PM »
It appears that the North Pacific has warmed up a lot:



That is a fairly big jump compared to anything else in the record, and suggests that maybe something a bit unusual is happening.  At the same time the North Atlantic is cooling a little, and now appears to be cooler than the North Pacific.



This is potentially interesting in light of a recent paper which suggests that the pause may relate to a warm North Atlantic pushing the Pacific into a La Nina like state  (link).  If this change in temperature balance between the North Pacific and North Atlantic persists, perhaps we'll see an end to the pause.  Of course perhaps a different explanation for the pause will turn out more accurate.  Or the current spike will reverse in a few months....

At the same time I note that the warm water volume for the west Pacific is at an all time August record by a significant margin.  (link).  Although the west WWV has been bigger in the past this has always been around the new year, and there is a strong seasonal component to WWV, as with most ENSO related statistics.  Furthermore the previous August records for WWV west have been set in 1989 and 2011 - just after strong La Ninas, which are associated with a build up of the western warm pool.  Whereas the current high anomaly is just after a massive Kelvin wave which has discharged a significant amount of warm water from the western warm pool.  In previous El Nino years the western warm pool had significantly shrunk by August.

Finally the PDO after several years of significant negative has gone substantially positive.  It peaked at 1.8 in May, which is higher than any time during the previous cool PDO phase (50s to mid 70s).  This spike in PDO has occurred despite and ahead of a mediocre spike in ENSO - nino 3.4 has barely made it past 0.5.  PDO often follows ENSO in the short term, but tends to by in sync with ENSO, or a little behind, and rarely leads as it has for this event.  While far too early to be confident of a sustained shift to a positive PDO, it is still interesting.
Climate change:  Prepare for the worst, hope for the best, expect the middle.