I’ve spent an inordinate amount of time working up a practical emulation of Mannian CPS and have uploaded a function to do this. While Mann has made a decent effort to archive code and intermediates, as others have noted, the code itself is chaotic and hard to figure out. Added to this are the “stupid pet tricks” – the allocation of proxies to more than one gridcell if they are on a fence-post, the unexpected (and unmentioned in the running text) 1 degree displacement of all gridcells to the south and the repetitive smoothing of truncated proxies at each step. Plus the archived reconstructions are spliced versions, so it becomes that much harder to reconcile.
However, with the help of UC’s Matlab runs and key assistance from CA readers (especially Roman’s filtfiltx function), I now have a working function manniancps which is presently located at http://www.climateaudit.info/scripts/mann.2008/utilities.txt. It requires the downloading of a considerable amount of data which can be carried out by executing http://www.climateaudit.info/scripts/mann.2008/collation.cps.txt (requires the package signal for Mannian smoothing).
A “verbose” version of the function will also yield various intermediates. These are compared to UC Matlab versions for the AD1000 step NH iHAD in the script http://www.climateaudit.info/scripts/mann.2008/replication.cps_AD1000.txt.
For comparison of reconstructions, I’ve used the SH iHAD reconstruction since, although the archived versions are spliced, the peculiar Mannian splicing procedure preserves the AD1000 network in this network, rendering it more useful for benchmarking than other networks.
Here is a comparison of my emulation of the SH iHAD cps series to the archived version.
Top – SH iHAD CPS – top: emulation vs archive (splice in this case); bottom – differences.
The algorithm sets three parameters to control for “stupid pet tricks” – smoothmethod; outerlist and lat.adjustment. If these are set to “sensible” procedures i.e. smoothing the entire proxy record once and using this smoothed record throughout; allocating proxies to only one gridcell and not displacing the gridcells, one gets a somewhat different NH reconstruction, as shown below.
The “pet tricks” have a not inconsiderable effect on the relationship between the 1930s and 1980s.
To analyze substantive issues like the impact of using Tiljander proxies upside-down, one has to wade through this stuff. It’s taken a while to get the emulation to stand still, but I should be able to now do these sensitivities in fairly short order. (The EIV recons remain a bit of a black box, unfortunately, and will take some time to parse.)
The differences arising from “stupid pet tricks” are, in some cases, a not inconsiderable proportion of the claimed uncertainty. At present, I have no idea how Mannian “uncertainties” were calculated. I asked Mann et al 2008 reviewer for information on this topic, and, in his best traffic cop manner, he told me to “move on” – which I take to mean that he doesn’t have a clue how they were calculated.