Here is the paper from MITRIE on climate reconstructions
M. N. Juckes, M. R. Allen, K. R. Briffa, J. Esper, G. C. Hegerl, A. Moberg, T. J. Osborn, S. L. Weber, E. Zorita, Millennial temperature reconstruction intercomparison and evaluation, Climate of the Past Discussions, 2, 1001-1049, 2006
There has been considerable recent interest in paleoclimate reconstructions of the temperature history of the last millennium. A wide variety of techniques have been used. The interrelation between the techniques is sometimes unclear, as different studies often use distinct data sources as well as distinct methodologies. Recent work is reviewed with an aim to clarifying the import of the different approaches. A range of proxy data collections used by different authors are passed through two reconstruction algorithms: firstly, inverse regression and, secondly, compositing followed by variance matching. It is found that the first method tends to give large weighting to a small number of proxies and that the second approach is more robust to varying proxy input. A reconstruction using 18 proxy records extending back to AD 1000 shows a maximum pre-industrial temperature of 0.25 K (relative to the 1866 to 1970 mean). The standard error on this estimate, based on the residual in the calibration period is 0.149 K. Two recent years (1998 and 2005) have exceeded the estimated pre-industrial maximum by more than 4 standard errors.
Update – Oct. 26
Some quick thoughts on the proxy selections. I’m sorting my way through this. It’s a full European Hockey roster with Briffa, Moberg, Esper etc. develop a “Union” reconstruction with 18 proxies, listed in their Table 1 with an asterisk. The proxies are pretty familiar.
Let’s compare the selections to my Hegerl predictions using my prediction numbering based on the least indpendence principle. The Briffa-Moberg-Esper et al reconstruction contains the following:
1. Yang composite – this is included. It’s listed twice in Table 1 under different alter egos, which BME did not identify as being the same; they correctly identify a couple of alter egos, but are not very accurate.
2. Taymir – this is in. Again it’s listed twice in their Table 1.
3. Polar Urals This is used TWICE in their reconstruction – once as the Briffa MXD version and once as the Yamal version of Briffa 2000. The Polar Urals update of Esper et al is NOT used, not is the version from Hegerl et al 2006 (which seems to be an average of the Yamal and Polar Urals update.)
4. Mongolia Surprisingly this is not used.
5. Tornetrask Again, this is unaccountably used TWICE in their reconstruction – once in the Briffa MXD version and once in the Esper RCS version. Their Table 1 attributes a series to Norway in Hegerl et al, but this is an alter ago for Tornetrask and another goof.
6. van Engeln This is not used, as it does not go back far enough.
7. Greenland dO18 This is used. Table 1 mentions three seemingly related versions, all referenced to Fisher et al 1996, using the version from Jones 1998. There is no archive for Jones 1998 and I’d previously concluded that the version used in Jones et al 1998 is identical to MBH. I had previosuly thought that the versions were all the same, but will need to examine this/
8. Jasper somewhat surprisingly not included, but the Luckman version does not go back to 1000 although it goes back nearly that far.
9. Bristlecones/foxtails Briffa-Moberg-Esper et al use no fewer than FOUR bristlecone/foxtail series – the two foxtail series used in Esper (and again in Hegerl). Their Table 1 fails to mention the use of these foxtails by Hegerl (or her use of Mann’s PC1). The other two versions are two series from Moberg (Methuselah Walk, Indian Garden) which do not have big growth pulses. Moberg inadvertently used the Methuselah Walk version twice, but it’s only used once here.
So the above series, which were my prime predictions for Hegerl, contribute 11 of 18 Briffa-Moberg-Esper series.
Other series in the Union reconstruction are:
Chesapeake Mg/Ca – used in Mann and Jones 2003, Moberg, Osborn and Briffa 2006
Quelccaya (accumulation and dO!8 from Core 2) – thus 2 series. Core 1, also used in MBH99, is not mentioned. The dO!8 series also contributes to Thompson’s tropical dO18 average. Guliya and Dunde dO18 from Thompson are important ingredients in the Yang composite.
GRIP boreholetemperature – this is a very high MWP value
Morocco morc014 – this is a tree-ring series from MBH98-99. It’s a functional equivalent of noise (and a precipitation proxy if anything)
Arabian_Sea:Globigerina_bulloides – we’ve talked lots about this. This measures G. bulloides foraminifera, associated with upwelling cold water. Comes from Moberg. Very non-normal.
Shihua Cave, China stalagmite – another Moberg series.
The following are excluded – I haven’t checked explanations yet:
Agassiz ice melt – perhaps a little surprisingly since it’s very HS;
Conroy Lake sediments – these have a high MWP and were in my apple-picking reconstruction
Sargasso Sea – also have a high MWP and were in my apple-picking reconstruction
Caribbean dO18 –
Tsulmajavri, Finland sediment
Indigirka ring widths – this has a high MWP and was in my apple picking reconstruction