A short delay explanation: I did say “further details following“, but following a minor stroke that “following” has had to become a flexible term. Not forgotten, but further down the list of priorities.
Placeholder for now. Discussion, explanations and further details following.
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There will be a short (I hope) pause while I investigate the stations used by GHCN to adjust Valentia. Complicated by the not uncommon situation in climate science that things are not quite what they seem. In this case the downloadable code dates from 2012, which should correspond to v3.2.0 — but in fact it seems to be code specially modified for a dataset for Peter Thorne, now of Maynooth. When reconfigured for GHCN input and run with GHCN-M v3.2.0 raw data the output is close to, but does not quite match, the corresponding GHCN-M adjusted data. Whether this is due to some hard-coded parameter or parameters which were not placed in the documented configuration files, or whether the modified basic code was frozen in time before all the modifications for v3.2.0 were completed, remains for the moment a matter of conjecture.
As the tutorial material I am adding will be excessive for those already familiar with some topics, I will finally shorten the post by moving out some expanded explanations to linked secondary posts.
This post started out to bring together a Twitter conversation:
The remaining corrupted Valentia GHCN-M data, dealt with further below, is relatively minor. But the facts that even after notification and ‘correction’ any such errors remain, and that 17 months later the nature of their errors in MCDW still seems to elude them, as evidenced by the absence of a code correction, can hardly inspire confidence in their claim that the problem lies just with ‘some mean temperature data for select stations in Ireland’.
This post now also provides an opportunity to clarify some common misunderstandings regarding surface temperature series as well as discussing the specific question above.
Owen M seems sound on energy, but has fallen into the trap of straying from the area he is familiar with and accepting what seems at face value an authoritative analysis, but one by someone else who has also strayed from the area they were familiar with, and not understood the source data they were dealing with. This is the reason I try to confine my own blog posts to Surface Temperature data sets, and in particular Gistemp and GHCN. It is only too easy to make errors when accepting other peoples work at face value without checking for yourself.
I dealt with Ewert’s errors in November 2015 when blogs picked up his material. At Not a Lot of People Know That (1), Not a Lot of People Know That (2), Not a Lot of People Know That (3) and NoTricksZone. At NoTricksZone unfortunately a flood of comments from one David Appell, although he was correct on this occasion, seems likely to have caused the substantive issue to become lost.