GWPF inquiring into temperature adjustments

Well, this is an interesting one. GWPF has announced an inquiry into temperature adjustment practices. It is being boosted by Booker at the Telegraph ("Top scientists start to examine fiddled global warming figures") which is a bad dent in its credibility. However, it has a reasonably qualified panel, so it may be interesting to see what they develop. They have asked for submissions by June 30, so I might try to come up with something. But the remit sounds like they have been advised by Paul Homewood. For now, I'll just review that:

Are there aspects of surface temperature measurement procedures that potentially impair data quality or introduce bias and need to be critically re-examined?

Are they talking about current practice? Or that of years past? Are they going to recommend how it should have been done back then?

How widespread is the practice of adjusting original temperature records? What fraction of modern temperature data, as presented by CRU/GISS/NOAA/BEST, are actual original measurements, and what fraction are subject to adjustments?

This is framed Steven Goddard-style. How widespread is the practice of doing arithmetic? People use records to calculate spatial averages etc, and may well wish to adjust for that purpose. As they should. Is detrending, say, an adjustment? Or calculating an anomaly?

 CRU/GISS/NOAA/BEST do present data. NOAA explicitly offers unadjusted and adjusted data. GHCN Daily is largely an unadjusted copy of what the national Mets have, and GHCN Monthly unadjusted is a straight average of that (for long-record stations). But the primary business of CRU/GISS/NOAA/BEST is the calculation of spatial indices. That is basically a spatial integration, and requires manipulation. They have to calculate estimates of what actually happened in sub-regions, and they publish that.

Are warming and cooling adjustments equally prevalent?

Goddard again. No. Why should they be? Adjustments are for the repair of bias. If the identified bias is down or up, the repair will rightly have the opposite effect. TOBS, in the US, has a clearly cooling bias. The reasons are well established in terms of observing practices of the past, and so correction is clearly warming.

Are there any regions of the world where modifications appear to account for most or all of the apparent warming of recent decades?

This is straight Homewood. There may be some. The inference is that there was a cooling bias that masked all of the warming. But it isn't common. If it helps them, the broad regional breakdown is here.

Are the adjustment procedures clearly documented, objective, reproducible and scientifically defensible? How much statistical uncertainty is introduced with each step in homogeneity adjustments and smoothing?

Well, it will be interesting if naysayers finally bring themselves to read the papers of Menne and Williams etc. But agenda may intrude. Statistical uncertainty of what, I wonder? Anyway, I'll probably send in a submission. I've been working out how to convert the html of blog posts to pdf. We'll see.

ps ATTP

Update. I noted something amusing. Booker's articles (based on Homewood) have clearly been influential in setting up the inquiry, and at GWPF, Peiser has prominently featured Booker's announcement in the Tele. But he modified the headline to
"Top Scientists Start To Examine Adjusted Global Warming Figures"
As I noted above, Booker's headline is actually:
"Top Scientists Start To Examine Fiddled Global Warming Figures"

I guess GWPF likes to sound a little more objective.

Update again. Here at Homewood's blog is Booker celebrating their achievement in staging the inquiry
"It was entirely prompted by the two articles I wrote in the Sunday Telegraph on 24n January and 7 February, which as I made clear at the time were directly inspired by your own spectacular work on South America and the Arctic."