Guest post by ducdorleans who is a Belgian civil engineer.
The Iceland Met Office (IMO) maintains some of the most carefully curated climate records in the World. This does not stop the Global Historical Climatology Network (GHCN) from tampering with the data, normally in a way that cools the past making today appear to be anomalously warm.
The winter of 1929 was an unusual one in northern Europe. In February 1929, for example, England was gripped by frost while Iceland was uncommonly mild. It was in fact 17˚ warmer in Reykjavik than in London. GHCN overcame this inconvenient historic warmth by simply changing +5.4˚C to -5.4˚C creating an 11˚C swing between reality and the version of history preferred by climate science. A forensic analysis of the weather station at Stykkisholmur is provided below the fold.
1. GHCN v1
This post was inspired by and builds upon Re-writing The Climate History of Iceland published on Energy Matters in February this year.
Bringing together, into GHCN v1, all (or most) available information from the hundreds of National (and maybe some private) Meteorological organizations from around the world – as done by The Argonne National Laboratory around 1990 – was a most commendable task. I can only begin to imagine the then workload.
Some individual MET’s had surely started their own GHCN-like task of bringing together and homogenizing their own meteorological data for temperature, pressure, precipitation and others. With some explanation on how their Fortran or Cobol generated data files were structured, and maybe some data quality control, these data were ready to be put into the Big Global GHCN database in a minute.
But others might just have come into the form of a printed book, or a handwritten ledger of records, with 1978 just after 1961, and just before 1945. Hard to recognize handwriting maybe? Diminishing ink?
This is what GHCN themselves have to say about it in the accompanying document for the GHCN v1 data.
All in all, not only commendable, but surely a Gargantuan task ! But also an extremely important one ! GHCN v1 is the original database, on which every other future version would (or should, but as it turned out “might”) base itself on.
2. Icelandic meteorological data
I got interested in the Icelandic temperature data because I read, on Paul Homewood’s blog, that the “original IMO data were available online”.
“Original data? … online!? “ … WOW!
I remembered – reading climateaudit.org e.g. here – Dr. P. Jones’ difficulties to get by “original data”. The struggle his department had with the national METs about them. The treaties between Governments and States over their use. And the difficulties to properly archive them, so that, if somebody asked for them a few years later, they were not lost in an office move.
And now, for Iceland, they would simply be available online ? …
A real climate science luxury!
3. Icelandic Met Office (IMO) website (http://en.vedur.is/ )
In view of the ongoing controversy over past temperatures, the IMO website is, as to historic data, what a meteorological website – IMHO – should be. Clear, open and transparent. Even the written or printed published records since 1873 can all be searched online (publications section of the about page)!
You are interested, for some strange – or just some – reason, in the temperature observation at 9pm on 21st October 1873 in Stykkisholmur ? … Well, it was -1,4°C, the highest observation of the day!
If you want to know some monthly values, no problem either … Interested in the observed average temperature during the month of March 1929 in Stykkisholmur? … This page is giving the answer: it was 5,4°C (it is on “Blaðsíða” 10 …)
4. Longer IMO temperature series
Apart from a model website, (at least some of) IMO staff don’t need FOIA rules to offer more help and information either. After my first looking into the different data sets, and with a faulty conclusion, I was wondering about them and sent an email to Trausti Jónsson, meteorologist at the Iceland Met Office. A prompt reply, and links to more information followed immediately. Iceland and Icelanders are taking their climate very seriously. No feet dragging, no formal request I had to put in … complete transparency, as it should be.
His reply email explained some – e.g. :
“Most of the observations made before 1870 are generally considered to be of a lesser quality than those made later – and some of them are. The dmi published icelandic data in their yearbook. We have made those accessible online. However, most of the temperature averages published there are not entirely compatible with later averages because of changes in observing routines – this is the main cause for the adjustments that we have made on the series.
The Stykkisholmur series proper starts in November 1845. The homogenisation of this was done in 1970 and the results published in 1975. There are no later adjustments to the Stykkisholmur series.”
(As a side note, what I never understood, both as a civil engineer and a citizen is that any data, in possibly the most lethal and most dangerous challenge mankind has faced in modern times – i.e. CAGW (catastrophic anthropogenic global warming) – , could possibly be hidden behind a paywall or FOIA rules. These data – especially these data ! – should all be publicly available at no cost and at all times. Because of all the possible dangers involved, both in human lives and economic losses, withholding any of them, or offering them at a price, should be a criminal offense !)
5. Why original data?
It is obvious that all and everything should and has to be compared to the original observations.
All over the world, there were the men and the woman who went out in the rain, heat, cold, the night, the day, to read that thermometer or that pluviometer, and what would possibly be their reason to NOT do it properly. I’m absolutely convinced that they took great pride in being the ones to have to do this work.
But, those original observations are not necessary the gospel. Maybe, the procedure – what they were told to do – could have been, looking backwards, sub-optimal and really should be adapted. And therefore the original observations might have to be amended, and/or corrected.
In Iceland, that was all done by the IMO starting 1970, as Mr. Jonssón wrote … “After that, I suppose that no other “homogenizations” would be necessary …” On his blog, he writes:
“Everyone can look up the numbers and compare both adjusted and earlier published values. Most of the later adjustments that have been made by the IMO are concerned with changes in the observing hours that necessitate slight adjustments. The methodology of the current calculation of monthly means is described in detail in:
Exactly the same method has been in use since 1956. There is no mystery surrounding the data from the Icelandic Meteorological Office. The current version (2003) of the Reykjavík data is available at the website of the IMO (and has been for many years):
and the Stykkishólmur series has not been adjusted since 1975 – only updated:
6. About the data, the used datasets, and the stations …
World Weather Records, “published since 1927“
leads to “temp.data” which I used – 23,103,900 bytes (accessed 11/03/2015)
|GHCN v2||Temperature files in the GHCN v2 database seem to have gone walkabout atm …|
( = “raw GHCN data + USHCN corrections”)
|GISS v3 hom.||http://data.giss.nasa.gov/gistemp/station_data/v3.mean_GISS_homogenized.txt.gz|
(Trausti Jónsson’s blog … this is a tabled summary of http://en.vedur.is/about-imo/publications/ )
- In july 2012, Mr. Jónsson posts “Temperatures in Iceland – as originally published” ( http://icelandweather.blog.is/blog/icelandweather/entry/1249149/ ) in which he gives other temperature data in the file “original_pub_temperature_values.txt” , linked with the stations whose metadata are in the file ” original_pub_temperature_stat_info.txt ” … these temperature data, I called “IMO unaudited” (imo U)
- So, I have 3 datasets – GHCN v1, and IMO “audited” and “unaudited” – with sometimes overlapping time frames.
( * = NO “audited” temperature data )
7. IMO vs GHCN v1
Ok, then … Since Stykkisholmur temperature data are available, in the GHCN and IMO datasets, for minimum the years 1846 to 1980, let’s compare them …
For all the months of the year, except January and March, hardly any differences … Both datasets seem to have been recording the same variable !
But what about January and March ? …
Up to nearly 12°C difference in certain years ? If we add those 2 months together, this is the result:
From beginning of the 1920ies up to the end of the 1940ies, GHCN v1 combined January + March monthly values are up to 15° colder than the IMO data. What is at work here ? Some highly scientific, wrought and otherwise profound algorithm that presumes GHCN v1 values more worthy then IMO values ?
Not really, just a change of sign ! The above mentioned REAL +5.4°C in March 1929 in the IMO dataset simply becomes -5.4°C at GHCN v1. (a quick sidestep to today: To make matters worse, in the GHCN v3 dataset, the real average temperature in Stykkisholmur has been tortured more to now become an even colder -5,71°C !)
Check it out in the original data, or in the accompanying excel sheet.
The case of March 1929
a) March 1929 in the original yearbooks
b) January to March 1929 temperatures in Iceland in the newspapers
Everybody can make mistakes in manually inputting values into a database. However, the methodical nature – only in January and March, and only in relatively warm months – of the error makes it less and less of a mistake, and more and more of an effort to slightly change the yearly values of the Stykkisholmur temperature record. The other stations have more of the same, i.e. changes to the original IMO data, but less obvious as at Stykkisholmur. Is this the aforementioned “quality control” at work ?
The idea and the database itself is excellent, necessary and commendable. But it should be done as a scientific task, not as another activist endeavor. Prof Ole Humlun – faculty of Mathematics and Natural Sciences at the University of Oslo, who also maintains the climate4you.com website – has recently started referring to the Hadcrut, NOAA and GISS world temperature series, all based partly on the GHCN database, as a lesser “quality class” compared to the 2 satellite datasets. In view of what I saw happening to the Icelandic temperature records, I would offer that he remains rather benign in naming them just 1 or 2 units less.