Reader Eric Worrall writes:
I was playing with Wood For Trees, looking at the relationship between Pacific Decadal Oscillation vs global temperature (Hadcrut 4), when the following graph appeared.
The interesting thing is PDO in this graph appears to have predictive skill for changes in global temperature – the changes in PDO appear to match changes in global temperature, once the graphs are normalised, but temperature lags PDO by around 5 years.
Source: http://goo.gl/hzOxW
Is it all just coincidence? Bad endpoint choice? Or does it in fact have some predictive value?
Readers are invited to weigh in.
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@ur momisugly Girma
Be careful interpreting the linked summary. Attribution is misplaced. AMO/AMOC = locally amplified manifestation (not driver). The phenomenon is global and externally governed.
http://tallbloke.files.wordpress.com/2013/03/scd_sst_q.png
Interpretive Caution: Temporal cycle acceleration/deceleration indicates spatiotemporal acceleration/deceleration more generally due to a simple relationship:
http://iopscience.iop.org/0004-637X/589/1/665/fulltext/57538.fg2.html
i.e. rate of change of rate of solar spatial pattern change = SCD
@rgbatduke June 5, 2013 at 5:12 pm:
“If the Pacific is almost half of the globe, and the PDO is a monotonic transform of the temperature of the Pacific as he seems to assert, why does global average temperature lag the average temperature of the Pacific?”
I looked up the WHOLE Pacific one time, and the number was 32%, which is about 1/3, not 1/2 the globe.
I’ve been up on this for a decade or so, and the PDO is NOT the entire Pacific, only the northern part of the northern half. Think in terms of north of Hawaii. Willis talks about it here as extending from the ENSO region to the upper reaches of the Pacific, but that is not how I know it. Perhaps someone has widened the definition when I wasn’t looking.
At the same time, the ocean north of Hawaii is itself a HUGE area, somewhat larger than Russia. It is the biggest monolithic named element in the climate equation, and being so large it is like an elephant in the room – the one that has pretty much been ignored, especially by warmists, who would lose a lot of their arguing points if a new natural element was seen as contributing so much. By comparison with the PDO any emissions by mankind are almost infinitesimally minuscule – CO2 or otherwise.
Of COURSE an element that large is going to affect the entire global temps – in ways far exceeding anything else. The PDO is several times larger than ENSO, so its effects should be relatively proportional. And humans have no effect on ENSO. ENSO leads. PDO also leads, as this shows. The 5-year lag mentioned here seems just about right, based on when the regime change occurred.
Willis has a nice concept here, tying ENSO and the PDO. It is certainly worth someone looking into some day. I would guess that with so much funding going into CAGW there is precious little funding left for real science.
…Steven Mosher asserts out that the PDO is part of the global temps, and therefore (he says) it is obvious that it is the same. That isn’t true, even on the face of it. Only SOME other areas of the globe swing up and down with the global averages. The evidence doesn’t show all of the regions in phase with the global. But with the terrible siting that Anthony points out in the US (still by far the most well-covered area), who knows WHAT the real regional phases do relative to the global.
People who knew about the PDO ten years ago (long before anyone else) were already predicting this present slowdown/pause/slight decline, specifically because of the regime change that occurred in the PDO from cool to warm, which they anticipated and then detected. And they have been spot on. And even with their rudimentary knowledge about the PDO they said the change would last from 20-30 years, if not more. So we are 1/3 or 1/2 the way through that.
Steve Garcia