We have focused considerable attention on the role of the Gaspé series in MBH98. While we alluded previously in MM05 (E&E) to information in our possession that the updated (1991) version of the series differed from the 1982 version and to our frustration that the updated version remains unarchived (see Jacoby #1) , we are now able for the first time to show the updated Gaspé site chronology and perhaps add additional flavor to our concerns over the impact of the use of the obsolete version.
Figure 1. Gaspé Site Chronologies. Purple (Ed Gas) – the 1982 version used in MBH98; Black (Gas) – the unreported and unarchived 1991 version.
In MM05 (E&E), we showed that the hockey-stick shaped Gaspé series was one of two influential outliers (together with the North American PC1 based on bristlecone pines) that caused the difference between MBH and MM-type results in the early 15th century. We showed that the unreported extrapolation of this series in MBH98 had a material impact on the reconstruction and that this extrapolation was concealed (perhaps unintentionally) by a misrepresentation of the start date of this series.
The impact of this series is compounded, because, in MBH99, the Gaspé series contributes to the Northern Treeline composite used for the MBH99 "adjustment" of the North American PC1. In the first part of the 15th century, the Gaspé series is the only contributor to Mann’s composite (including portions where there is only 1 or 2 trees) and undoubtedly contributes disproportionately to the MBH99 conclusion of "similarity" between the two series.
In passing, and I’ll post this on the Bristlecone Pine Adjustment theme as well, Jacoby begins his temperature reconstruction only in 1601, while Mann’s composite of the Jacoby versions (used for "adjustment") begins in 1400. But what bugged me more than the use of 1-2 trees is the withholding of the updated version. In the updated (1991) Gasp” chronology, there is obviously no hockey stick shape at all. However, Jacoby et al. are "mission oriented" and decided that they would not archive the new data, even though it had been funded with public money. Their argument is presumably that there’s something wrong with the new data – let them argue that and show it.