Take a look at today’s puzzle.
On the left, I’ve plotted the three EIV reconstructions for the NH hemisphere using the infilled CRU series as a “target”. The data is straight from Mann’s website. One shows the “full” global network, one shows the “full” NH network (both of which I take to really be series selected as discussed in my Full Network post, but it’s always hard to be sure) and the third one is the “screened” NH network. As I understand it, SH proxies are used in the “GL full” network to teleconnect with NH reconstruction and this is the difference with the NH “full”, but again I’m not 100% sure.
The right panel shows the differences between the series, showing the differences in a cycle.
Take a careful look at both panels because lots of questions jump out at me.
First, all three reconstructions go to 2006 even though there aren’t any proxies that go to 2006. How’d they do that? (Of course, we can’t tell by consulting the EIV code, because, contrary to the representaton by PNAS, working EIV code isn’t provided.) Did they splice the instrumental record? Could be. It’s hard to tell.
Second, all three reconstructions are identical in the calibration period. How’d they do that? Is this from splicing or overfitting?
Third, look at the the year 600 in the right hand panel. The black and red series essentially flip orientation. How’d they do that? It looks like there’s a reconstruction step and the regression sign for a series flips over when the composition of the network changes. Whatever it is, it’s not a good sign,
Fourth, what about the green series in the left hand panel. What’s going on in the early portion? How’d they do that?
Just to show that I’m not making this up. Here’s a graphic from the SI in which I think that I discern some of these patterns:
Stranger and stranger.