Let’s move from the 2 column case to the 3 column case (e.g. Bagdarin, already considered) applying the results here. Some of the hypotheses from the earlier discussion have to be re-visited. Bagdarin has 3 dset=0 versions (0,1,2). As we’ve seen in the 2-column case, the column that continues to the present (version 2) exactly matches the dset=1 version in the later part of the record when there is only version. Bagdarin version 0 is reduced by 0.3 deg C, version 2 by 0.2 deg C. Given these adjustments, dset=1 more or less follows.
Versions 0 and 1 are scribal variations for 1980 and after and from 1951 to 1960, but are discrepant between 1960 and 1980. For analysis, it might be a good idea to find a record that has 3 columns and is only scribal.
Hansen and Lebedeff 1987 describe an iterative procedure for combining the versions net of the deductions. My experiments indicate that this boils down to a simple unweighted average of the versions net of deductions, but this is experimental so far.
Hansen’s description (for whatever that’s worth) indicates to me that he first calculated the delta between versions 0 and 1 (or alternatively between 1 and 2), then formed an interim composite and repeated the procedure. However, I couldn’t get everyting to work. If I apply the proposed 2-column Hansen-delta calculation to versions 0 and 1, I get a delta of -0.2, followed by a delta between the interim series and version 2 of +0.1: so this doesn’t work.
If I try version 1 against version 2 first, I get a delta of 0 followed by a delta of -0.2 between the interim series and version 1.
These deltas seem quite unstable to ordering in a first peek.
So today’s puzzle: find a system for the 3-column case, consistent with 2-column results.
Of course, Hansen could always free the code.