Many of us have seen the article by Willis Eschenbach over at the Anthony Watts site, “Smoking gun at Darwin Zero” (SGDZ) . I disagree with Willis that the strongly warming GHCN Darwin 0 data has been used by CRU.
Fig 1 in SGDZ shows a small IPCC diagram with a sketch temperature trend for Northern Australia for the period 1900’s to 2000. Willis found that the GHCN adjusted Zero version for Darwin warmed very strongly post 1940, see his Fig 8.
That trend in Fig 1 looks to me to agree with the land only CRUT3 trend that anyone can generate for that Northern Australia region using the useful KNMI Climate Explorer page which lets you interrogate many monthly global databases – enter link on right to Monthly observations.
Downloading CRUT3 and NCDC GHCN for the period 1907-2000 I get trends over the 94 years of 0.48 for CRUT3 and 0.87 for NCDC GHCN.
Following four graphics all from KNMI Climate Explorer
IPCC Northern Australia region – trend for CRUT3
IPCC Northern Australia region – trend for NCDC GHCN
Darwin grid cell – trend for CRUT3 (I think they are wrong to join Darwin Post Office to Aiport like that) No sign of Darwin Zero here.
Darwin grid cell – trend for NCDC GHCN
To wrap up this section re Darwin Zero, I am saying the GHCN Darwin Zero data is not used in CRUT3. What a shambles the global T datasets are.
Willis says in SGDZ “One of the things that was revealed in the released CRU emails is that the CRU basically uses the Global Historical Climate Network (GHCN) dataset for its raw data.”
IMHO you have taken this idea too far Willis and this has lead to the mistaken impression that GHCN Zero is causing the trend in the Fig 1 IPCC graphic at SGDZ.
Jones et al 1986 constructed their foundation data before GHCN was even published !! We have Jones et al station documentation for those 20 year old versions of CRUT (they included Darwin from 1882) – that provided global warming trends for the commencing of the IPCC at the end of the 1980’s – the Rio Conference in 1992 – Jones et al 1986 was in every way the BIRTH OF GLOBAL WARMING as we now know it. The GHCN followed along afterwards and basically agreed.
Sure, from his Jones 1994 update – Jones inserted many more stations and common sense tells you many of these must equate to GHCN sites. But I would bet my bottom dollar that they were all carefully sifted, scrutinised and altered where required by Jones / CRU before being used. Remember we do have the Jones 94 station data – but we do NOT have 1994 station documentation equivalent to the 1986-1991 TR022 and TR027 books published by the US Dept of Energy, CDIAC, refs here
These books are out of print, I hope people ask CDIAC to do another print run of the 1991 edition. It would be great to ask CDIAC for updated documentation books with all current station data too. Remember the DoE have been funding Jones / CRU from the early 1980 and I bet still do.
Back to Willis’ contention that “..CRU basically uses the Global Historical Climate Network (GHCN) dataset..”.
The Jones & Moberg 2003 update was a monster cut n paste n fill – mix n match, as stations numbers blew out to over 5,000.
There was no station data or TR022-27 type documentation for this version – but we have to assume their methods were basically as set out in TR022 and TR027. IMHO around this time senior UKMO people got uneasy at the developing shambles that was CRUT2 and planned the ending of that series in 2005 and the migration of the project across to the UKMO / Hadley Centre as CRUT3 with Jones as the “tail end author” in the Brohan paper.
See my; Huge variations now between the 3 main global T datasets
An example in detail: Hadley Centre inserts more warming into New Zealand climate history
I notice 24 Nov 09 statements by CRU saying, “It is well known within the scientific community and particularly those who are sceptical of climate change that over 95% of the raw station data has been accessible through the Global Historical Climatology Network for several years”. IMHO that was a classic example of misinformation and obfuscation – of which there are many examples in the last 25 years of climate saga. We should not be lead astray by CRU / Jones attempts to divert us from requiring that they reveal all their station data. As I say above, any GHCN stations incorporated in Jones et al data would have been “..carefully sifted, scrutinised and altered where required by Jones / CRU before being used”.
Let me just finish by saying, nobody will ever understand what Jones / CRU have done by studying the GHCN – which is riddled with its own errors.