The missing hockey stick is found hiding in central England
Tamino has been looking at the CET - Central England Temperature record - and does some clever stuff picking out a few potential problems with the older records. (The direct link above to the blog post doesn't seem to be working so you may have to go Tamino's main blog page to find his article.) But he ignores the fact that this "longest single instrumental temperature record" has been buggered about with, especially since 1974. with station changes, adjustments and tweaking, all with the good intention of "improving" the record.
But no matter because he takes this: The monthly temperature anomalies - the difference between each month’s value, and the average for that month during a reference period (the entire time span ).
And by his sooper secret process - " I used a *modified* Savitzky-Golay filter because I apply a weighting function of my own design, tailored to minimize the impact of noise on the result. I called it "Savitzky-Golay" without the "modified" because this post is not about filters, so I decided to keep it simple. I'm working on a peer-reviewed publication to introduce my new weighting function. Furthermore, I also applied a wavelet filter and a low-pass filter. The results are the same. The very large warming in the last 30 years is real, and shows up just as prominently in all the filters I applied."
He turned it into this!
Hurray! The hockey stick is back! Trebles all round! But he can do better: "I’ve also plotted lines marking out the episodes of known changes in the precision of the data...If we plot only the most precise part of the data, from 1800 to the present, we get a very clear picture of the climatological changes in CET for the last two centuries:
Bish, bash, bosh; job done.