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Yesterday, Kemp et al. 2011 was published in PNAS, relating sea-level variation to climate over the past 1,600 years (UPenn press release). Among the authors is Prof. Mann. (Kemp11 is downloadable from WUWT.) Figs. 2A and 4A are “Composite EIV global land plus ocean global temperature reconstruction, smoothed with a 30-year LOESS low-pass filter”. This is one of the multiproxy reconstructions in Mann et al. (2008, PNAS). The unsmoothed tracing appears as the black line labelled “Composite (with uncertainties)” in panel F of Fig. S6 of the “Supporting Information” supplement to Mann08 (dowonloadable from pnas.org).

This is one of the Mann08 reconstructions that made use of the four (actually three) uncalibratable Tiljander data series.

As scientist/blogger Gavin Schmidt has indicated, the early years of the EIV Global reconstruction rely heavily on Tiljander to pass its “validation” test: “…it’s worth pointing out that validation for the no-dendro/no-Tilj is quite sensitive to the required significance, for EIV NH Land+Ocean it goes back to 1500 for 95%, but 1300 for 94% and 1100 AD for 90%” (link). Also see RealClimate here (Gavin’s responses to comments 525, 529, and 531).

The dependence of the first two-thirds of the EIV recon on the inclusion of Tiljander’s data series isn’t mentioned in the text of Kemp11. Nor is it discussed in the SI, although it is an obvious and trivial explanation for the pre-1100 divergence noted in the SI’s Figures S3, S4, and S5.

Peer review appears to have been missing in action on this glaring shortcoming in Kemp11′s methodology.

More than anything, I am surprised by this zombie-like re-appearance of the Tiljander data series — nearly three years after the eruption of the controversy over their misuse as temperature proxies!

Not sure if you are refering to the report on this page…

http://www.publications.parliament.uk/pa/ld200506/ldselect/ldeconaf/ldeconaf.htm

They looked at the hockey stick debate and concluded that they were not qualified to give a view, but did comment that “One curious feature of the debate over Professor Mann’s time series is that the critics appear to ignore other studies which secure similar hockey stick pictures”. The report’s footnote to this is to: K. Briffa et al. Low frequency temperature variations from a northern tree ring density network. Journal of Geophysical Research, 106, (D3), 2001, 2929-41. Hilarious.

Interesting, if one checks the reconstruction without UC’s “red paint”, it seems that MWP values are higher than current values, and early values are skyrocketing. So the Tiljander series and bristlecones do indeed “matter”, don’t they?

AD1000 temperatures seem to get some boost when one skips Tiljanders and dendro, and even more when the both are dropped. No Tiljander, forget the Mann-Smoothed-hemispheric-scaling ( hey, Kaufman had a better method *), no red paint = no HS ?

* with some problems http://www.climateaudit.org/?p=7005

> Amac – 26 – Are the proxy weights relevant to your query?

My understanding of these issues isn’t adequate to answer.

The concept is that the 810-850 valley is a prominent feature of the anomaly trace. According to Jean S (#8 supra), the addition of the four Lake Korttajarvi series is the only pre-1700 difference between the Fig. S8a “NH CPS minus 7″ trace (Black) and the “Original CPS NH” trace (Green). Given that there is no obvious “cooler” or “warmer” signal in those series (with respect to, say, 750-800 and 850-900), the coincidence of Black and Green is notable.

That superpositioning is likely the consequence of the absence of a 810-850 dip for temperatures calculated by RegEM for the grid box that covers Finland.

So my question becomes, is there a way to identify that grid box and the RegEM-calculated temperature anomalies for that box? If so, that series could be graphed against the Lake Korttajarvi proxies, 750-900.

Another error

Interesting choice of words.

Rather than say Corrigendum 1, 2 etc, so you can track how many, we just get a date and “Another”.

Not a good look in any event, “Another!”

Amac – 26 – Are the proxy weights relevant to your query?