KNMI has been measuring the wrong temperature for years
WUWT reader Mike writes with this little bombshell on one of the world’s leading meteorological agencies. It seems they can’t get their thermometer siting correct which resulted in a bias to the record. Hmmm. Where have we heard this before? The newspaper “AD” in the Netherlands has picked up the issue with two separate stories.Mike writes:
Dear Anthony,
I left this on the “tips” thread on WUWT, but since it is also relevant to surface stations, I felt you should hear of it directly. It probably deserves a whole story on WUWT.
As you probably already know, KNMI De Bilt is the only station in the Netherlands used for GISTEMP. The nearest long-term station is in a suburb of Brussels, hence is undoubtably UHI-polluted. De Bilt is the only long record stn in NL & within 150km in any direction would be a useful correction.
Two stories caught my eye in the Dutch papers today about a 0.5-degree error in the De Bilt record which was miraculously corrected this summer with a station move of 200 m without anyone being told of it. Here are the links to and my translations of the articles.
Mike’s translations of the newspaper stories are below, I’ve added relevant graphics. – Anthony
The instrument stood too close to a line of trees, due to which on average half a degree (Celsius) too high was measured.
After discovery of the fault the thermometer was moved to an open spot on the measurement field before last summer, the KNMI has confirmed. Due to the change the average measured temperature fell half a degree. This measurement should be reliable.
The mistake resulted in that the KNMI has announced more “official” summery and tropical days than there were in reality. According to the Institute, the defect has not or hardly influenced the scientific discussion on climate change, because researchers use the data from a large number of weather stations. SUZANNE DOCHTER
Above: GISS Temperature plot for De Bilt KNMI – notice the step function. Click for source data.
Here’s a picture and metadata for De Bilt, direct from KNMI. While I can’t be certain, this photo appears to be after the move:
Checking some nearby stations in GISS, click for source data:
The GISS plot for Maastricht Airport:
One whole data point? Why does GISS keep a station in the database with only one data point?
UPDATE: Well if GISS can’t find the data for Maastricht Airport, everybody else can, and damn quick:
See Weather Underground for current conditions.
And this website, tutiempo.net , has the complete climatic data set back to 1949.
http://www.tutiempo.net/en/Climate/Maastricht_Airport_Zuid_Limburg/63800.htm
Call out to GISS: Hey Gavin, as an American Taxpayer that funds your work, I request you take a moment from moderating realclimate.org and put some work into updating this record.
Here’s the next closest station, Essen, according to GISS a city of 7.5 million – doesn’t look much like the KNMI record:
2nd story —
KNMI has been deaf to criticism for years
WAGENINGEN – weather Institute KNMI has been deaf to years of criticism from competitor Meteo Consult of its temperature measurements in De Bilt
Weather specialists from the Wageningen-based Meteo Consult have been expressing their distrust for years, because the KNMI figures in De Bilt were always a bit warmer than in Cabau, 16 km away, where there is also a KNMI thermometer. The position of both places could, according to Meteo Consult, not explain the temperature difference of on average half a degree (Celsius). It was also not taken into account that De Bilt is located in a more built-up, and probably therefore warmer, surroundings than Cabau, near IJsselstein.
The meteorologists from Wageningen discovered this summer to their amazement that the temperature difference between both places in the KNMI figures had more or less disappeared. On enquiring of the De Bilt employees, it appeared that the thermometer had been moved. Since the intervention, the measurements from De Bilt show not 1/2°, but on average just 2 hundredths of a degree warmer than Cabauw, according to the spokesman of Meteo Consult.
This summer it appeared that the temperature difference was suddenly resolved. Again discussions blazed between the weather specialists and it was decided to closely compare the measurements between Bilt and Cabauw. “It was thus discovered that last summer in De Bilt was still 1/2 degree warmer and this year there was just a difference of 0.02 degree Celsius”, explained a spokesman of Meteo Consult.
The organisation decided to call the KNMI and heard that the “weather cabin” [translation: Stevenson Screen], in which the thermometer is located, had been moved. According to the KNMI the measuring instrument stood too close to a row of trees. Because the trees continued to get taller, the wind began to influence the temperature measurements too much. Now the “weather cabin” has been moved 200 m away, to a more open spot on the measurement field of De Bilt. KNMI employee Cees Molenaars cannot say how much influence the old placement of the thermometer has had on weather reports. “We must investigate that. We only regret is that we did not keep Meteo Consult and other parties informed of the movement.”
The thermometer of De Bilt is the official measurement used for determining heatwaves, cold waves, and summery days. To speak of a heatwave it must be at least 25°C released 5 days. Also it must be warm than 30° for 3 days. At 25° one can talk about a summery day.
With a cold wave, freezing temperatures must be measured for 5 adjoining days at De Bilt, with also 3 days with a hard frost. “The differences in minimum temperature between de Bilt and Cabauw were much smaller,” said the spokesman of Meteo Consult. “The chance that a cold wave is missed, is thus smaller.”
The thermometer in De Bilt has less influence on KNMI weather predictions. These are performed on the basis of the data of tens of measurement stations. Further, for scientific purposes, such as climate change research, the central Dutch temperature was brought to life long ago. For this, data from various stations is used [NOT TRUE — GISTEMP ONLY USES DE BILT!]. Meteo Consult are above all happy that the riddle has been solved. For fun they have also calculated what an extra half degree in De Bilt would have meant for this summer: 5 extra summery days and 2 tropical ones.
====================
Coincidentally, I’ve been conversing with Jos de Laat of KNMI, the Dutch Meteorological Institute who offered some scans of weather station siting specifications from the World Meteorological Institute (WMO)
he writes:
OK then, you can find the first part of the report here (~ 1 Mb):
http://www.knmi.nl/~laatdej/TMP/WMO488.pdf
Especially the beginning of part 3 is relevant, I guess. Because of document size considerations for now I only scanned up to paragraph 3.1.2.1.7 (after paragraph 3.1.2.1.7 the description of requirements for measuring on other locations like sea and the free troposphere starts).
Descriptions of sensor and siting requirements are also available online (see below) …
… but they are more formal and largely based on WMO report 488, which contains some interesting quotes that are not present in later reports. The online reports also refer to the report below, which unfortunately I was not able to locate either online nor in our library.
World Meteorological Organization, 1993a: Siting and Exposure of Meteorological Instruments (J. Ehinger). Instruments and Observing Methods Report No. 55, WMO/TD-No. 589, Geneva.
These specs are worth a read, because they show that quite a lot of thought and analysis went info choosing the specs.
As for the 100 feet cited by the NWS on this page: http://www.nws.noaa.gov/om/coop/standard.htm
I suspect its a round off of 30.48 m where 30 meters is the minimum distance to an artificial heat source cited for a Class 2 climate site as defined by the specs used in the Climate Reference Network (CRN) which has a French lineage, and likely traces back to WMO.
It seems that no matter where you look, meteorological agencies can’t follow siting specifications.
Steve McIntyre of Climate Audit has more on De Bilt and the adjustments that are being applied there:
http://www.climateaudit.org/?p=1650
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rbateman (09:49:54) : Who needs GISS? Seems like a boat anchor attached to NASA, dragging down the parent institute’s credibility. The question I would like answered is this: Is GISS really necessary and can it’s functions of meteorology be handled/absorbed by another Fed. institute with better credibility and accountability?
Having gone through all of GIStemp I can tell you that the only part I would keep is the “glue together the Antarctic data sets and GHCN” bit early in STEP0.
There are 6 steps numbered from 0 through 5. Step 4 just updates the Hadley SST anomaly box file. Step 5 merges this with the GIStemp land data. Given that Hadley data are now “the dogs lunch” I see no reason to keep STEP4_5 (it is a composite step).
STEP3 does a boxing / gridding process. It takes temperatures that it has fabricated (via a variety of oddball processes) and smears them around over an area up to 1200 km in radius. This, unfortunately, does not do what the AGW advocates assert in that it does not suppress one bad thermometer from having influence. In fact, one bad thermometer can warm an area about 1/2 the size of the continental USA (and does so).
See the impact of Diego Garcia, for example:
http://chiefio.wordpress.com/2009/09/08/gistemp-islands-in-the-sun/
So STEP3 is bogus just because all it does is take broken temperatures (largely based on airports) and smear them over far larger areas than they would otherwise screw up.
OK, what about STEP2? As seen in the “slice of pisa” link above, it takes temperatures from cold places and uses it to give an upside down UHI correction to places like PISA. It does not achieve it’s stated goal in that the anomaly phase in it does not suppress the real impact of actual cold places on the temperature series. The anomaly code does not work as advertised.
So jettison STEP2.
STEP0 takes the antarctic data, GHCN data, a “special” copy of Hohenpeissenberg data and glues them all together. Unfortunately, it also mucks around with an strange “unadjusting UHI” step as it does this merger and it has a slightly broken F to C conversion that warms 1/100 of the records by 1/10 C each. Easy fix: Use the GHCN “adjusted” records and forget about the GIStemp UHI farce. This also eliminates the F to C problem and gets rid of the strange “unofsetterizing” and merging process.
http://chiefio.wordpress.com/2009/07/30/gistemp-f-to-c-convert-issues/
So we are left with Hohenpeissenberg. Take a look at the data, if clean, let it in, if not, use the GHCN record.
And finally there is STEP1. This step uses stations from up to 1000 km away (or maybe it was 1200 km… GIStemp keeps changing the radius it likes to use from STEP to STEP. Cherry picking is so messy…) to re-imagine the temperature series by fabricating data where there are none. While it looks like it MIGHT be OK, it also looks like it does not contribute much to the process. Through STEP1 the temperature series are warmed by about 1/2 C (in addition to any bogus temperatures recorded in the first place).
http://chiefio.wordpress.com/2009/08/12/gistemp-step1-data-change-profile/
I see no reason to add 1/2 C to the data series while fabricating data that do not exist. So I’d toss it too.
That leaves the simple process of:
Get NOAA GHCN Adjusted data, merge Antarctica. Done.
I would then look at the long lived thermometers (not bothering to re-imagine data that do not exist) and simply ask them what to they say. What they say is that there is no warming:
http://chiefio.wordpress.com/2009/08/13/gistemp-quartiles-of-age-bolus-of-heat/
So at the end of about 3/4 of a year of work dragging my brain through GIStemp code, my conclusion is that the world would be better off tossing it in the dust bin and using the straight GHCN data plus Antarctic.
Anyone who supports the use of GIStemp has not analyzed what it does.
It sucks to be caught with your weather station pants down!
Here is some real data on the measurements site in De Bilt:
==============
Source: http://www.knmi.nl/publications/showAbstract.php?id=426
Parallel air temperature measurements at the KNMI-terrain in De Bilt (the Netherlands) May 2003 – April 2005
November 2004
by T. Brandsma (KNMI),
Abstract
From May 2003 through April 2005 a field experiment is being carried out
at the terrain of KNMI in De Bilt. The objectives of the experiments are to
study the representativeness of the current operational air temperature
measurements site and to explore the possibility of using present-day parallel
measurements to correct for inhomogeneities, caused by changes in the
surroundings and a relocation of the thermometer screen in 1951. At five
locations, including the operational location, temperature and wind speed
are measured at a height of 1.5 m every minute, using identical instruments.
The temperature differences between the sites are studied in connection
with wind speed differences and operationally measured weather variables.
The experiment is part of the KNMI-program ‘Hisklim’ (HIStorical
CLIMate). The measurements can be followed real time at the KNMIintranet
site http://info.knmi.nl/ks/hisklim/Parallelmetingen/.
The present interim report presents the results of the first phase of the experiment
(May 2003–April 2004). The report is meant to serve as a basis
for deciding upon the optimal future location of the current operational
temperature site. A Final report will be published at the end of the experiment.
Full text (pdf: 5 MB): http://www.knmi.nl/publications/fulltexts/hisklim7.pdf
==============
Source: http://www.knmi.nl/publications/showAbstract.php?id=5759
Understanding of inter-site temperature differences at the KNMI terrain in De Bilt (the Netherlands)
2008
by T. Brandsma (KNMI),
Abstract
From May 2003 through June 2005 a field experiment was carried out at the KNMI terrain in De Bilt. At five sites, including the operational site, temperature and wind speed were measured at a height of 1.5 m every minute, using identical instruments. The temperature differences between the sites have been studied in connection with the wind speed differences and operationally measured weather variables. During the experiment (in October 2004) a renovation of the nature area just west of the operational temperature screen took place. The renovation introduced an inhomogeneity in the temperature time series at the operational site. The inter-site temperature differences are largest in summer and smallest in winter. Except for the most enclosed site, these temperature differences have opposite signs for daily maximum and minimum temperatures. As could be expected, the magnitudes of the differences strongly depend on the weather conditions. The understanding of these dependencies is an important condition for improving the homogenization of daily temperature series.
TonyB (12:57:20) :
These are primarily due to vast numbers of ‘cold’ stations being withdrawn in Russia following the end of the approriately named cold war.
I trust that you are not implying that removal of cold stations will increase the rise in temperature?
Only anomalies are used in global averages (there is no other possibility) so of course the absolute temperature of individual stations does not affect the average.
Good one! LOL
Don’t forget that this works both ways. Those born in recent decades are likely to see a return to a more 70’s like climate over the coming decades.
If the cyclic nature (at least in this locale) is real, it would cause a lot of problems for places like the UK where AGW has been accepted more readily for the reasons you outline. Planning and taxing for a ‘Mediterranean’ climate while snow frequently brings our infrastructure to a grinding halt.
Meanwhile in Finland the Finnish Meteorologial Institute finds that due to UHI the night temperatures can be up to nine (9) degrees higher than in neighbouring urban areas.
This affects Helsinki metropolitan area in particular.
http://translate.google.fi/translate?prev=hp&hl=fi&js=y&u=http%3A%2F%2Fwww.fmi.fi%2Fuutiset%2Findex.html%3FId%3D1253684912.html&sl=fi&tl=en&history_state0=
3×2: If the cyclic nature (at least in this locale) is real, it would cause a lot of problems for places like the UK where AGW has been accepted more readily for the reasons you outline.
The optimistic olive (indeed – but in Cornwall, I think) and wine farmers may have to move to Tuscany to fulfill their dreams – after all 😉
@ur momisugly E.M.Smith
http://chiefio.wordpress.com/
So at the end of about 3/4 of a year of work dragging my brain through GIStemp code, my conclusion is that the world would be better off tossing it in the dust bin and using the straight GHCN data plus Antarctic.
Anyone who supports the use of GIStemp has not analyzed what it does.
Very few people have analyzed the GIStemp code, but you have, and we are in your debt. WUWT is fortunate to have people like you who dig into the details of the science and separate the slag from the AGW output.
It must be frustrating for the ‘professionals’ to put together a scientific paper or process, then have WUWT ‘amateurs’ go through them and not only point out the errors, but then reverse engineer their secret methods and generate the results they should have gotten.
Again, Danke. (is that Dutch or Danish?)
When iused to drive to work from a village 10 miles outside Munich Airport to the airport my car thermometer always jumped at least 1 degree c no matter what time of year or time of day.All that tarmac and concrete holding on to heat.Airport heat island,how many weather stations do airports have, that might find their readings ending up in climate data..
@Mike McMillan
Danke is German, ‘Dank je wel’ is Dutch
“De Bilt were always a bit warmer than in Cabau, 16 km away, where there is also a KNMI thermometer.”
In reality, the distance is about 36 km.
In reality, the difference over time has varied from zero to 0.5° C (which is minimal in all respects). It is statistically not possible to determine whether the hut had been displaced or not.
In reality, the difference of +0.5° C is on average maximum temperature, not on average temperature. The difference between min and max in the Bilt is a little larger than in Cabauw simply because de Bilt lies on sandy ground whereas Cabauw is mud. The difference of average max has varied between zero and a degree since the start of Cabauw in 1986 and may be attributed to said sandy underground and of course weather.
In reality, the average daily temperature on the new location was found to be 0.15° C higher, though this difference has no significance.
The ‘step function’, that is the sudden warming as of 1988, is real, no artefact. It is shown by all Dutch stations. It is reflected in e.g. the fact that skating on canals was possible 9 out of 10 winters prior to 1988, 4 out of 10 between 1988 and 2000, 2 out of ten this century.
July 2006, the hottest month ‘ever’ (shall we guess: about 4.000 years?) was real. I can’t stand that kind of Spanish heat and lost 10% of my bodyweight in those weeks.
Essen is a city of about 540.000 inhabitants but situated in the so called “Ruhrgebiet” an industrial area since the 19th century with a very high density of population. There are many cities quite close to each other like Essen, Dortmund, Duisburg, Bochum, Oberhausen. In former times this area was famous for coal mines, steel (Krupp) and heavy industry.
Re: Mike McMillan (00:27:02) :
“Again, Danke. (is that Dutch or Danish?)” – Neither, that’s German. Danish: Tak. Dutch: Dank.
Nice, these reactions from KNMI employes. And indeed, they have a lot to defend, in the first place their unassailable position in the dutch mainstream media concerning the holy AGW belief. In the second place of course their wages and funding as provided by the dutch ministry for economic affairs. KNMI nowadays is nothing else than a red-green propaganda institute collaborating with the government to oppres and indoctrinate the country in a stalinistic way.
@Mike McMillan.. Danke is German!
Anyway here is all the official DATA for De Bilt (maastricht and others are also there)
http://www.mscha.org/knmi/summer.cgi?station=260&sort=year&month=-1&columns=more
the average annual temp in the netherlands is 9.8 C (
here is the report from the parralel measurement before the move
it states that the old location is on average -0.15C colder !
http://www.knmi.nl/publications/fulltexts/hisklim7.pdf
Joel Heinrich : Uccle is part of Brussels. Brussels is formed of 19 borough like Paris 20 “arrondissements”, so the population of Uccle should not be considered as 76K but well at 1 million for Brussels
rtgr (02:58:24) :
Anyway here is all the official DATA for De Bilt (maastricht and others are also there)
http://www.mscha.org/knmi/summer.cgi?station=260&sort=year&month=-1&columns=more
What kind of adjustments have been applied to these temperatures?
They are very different from the unadjusted GISS data:
http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=633062600000&data_set=0&num_neighbors=1
and has even more trend than the adjusted GISS Data:
http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=633062600003&data_set=2&num_neighbors=1
At times when I consider the AGW argument, I feel as though I stepped through the looking glass.
Alice laughed, “There’s no use trying,” she said, “one can’t believe
impossible things.”
“I daresay you haven’t had much practice,” said the Queen. “When
I was your age, I always did it for half-an-hour a day. Why,
sometimes I’ve believed as many as six impossible things before
breakfast.”
In these discussions, humor, sarcasm, and irony have to be INDENTIFIED. The pro-AGW arguments become so tortured that they are parodies of themselves. So, ridiculing them has to be identified as ridicule so it won’t be taken as a serious comment.
By the way, I am guessing that:
Re: Mike McMillan (00:27:02) :
“Again, Danke. (is that Dutch or Danish?)”
is a subtle attempt at “engineer humor”. To imply that a German word is either Dutch or Danish is vaguely insulting to all parties. Sort of like saying Texas and California are the same. (I was working with a Dutchman and I mistakenly spelled his last name Von… instead of Van…. He promptly explained the enormity of my crime against the Dutch
People.)
Anthony,
Please keep up the good work. We need you!
Regards,
Steamboat Jack
RR Kampen: July 2006, the hottest month ‘ever’ (shall we guess: about 4.000 years?) was real.
4000 years? Come on! It may be the hottest month for 100 years in the Netherlands, but there are close contenders. And since June and August were not so hot, the summer 2006 wasn’t that extraordinary.
According to GISS data for de Bilt (I’m using the homogenized data now), the following are the 11 hottest June-July-August periods:
1947
1911
1935
1976
2003
1933
1939
1941
1983
2006
And according to the even more “homogenized” (i.e. upwards trended…) dutch data posted above, 1947 also had higher max temp than 2006.
So please, don’t conclude anything about climate from one hot summer month…
Re: Espen (06:16:07) :
“4000 years?”
That is the calculated return time for a July with such a great anomaly.
“Come on! It may be the hottest month for 100 years in the Netherlands, but there are close contenders.”
For July 2006 there are simply none. Temperaturerecord back to 1706, with some small interludes back to 1634, nothing like it.
“And since June and August were not so hot, the summer 2006 wasn’t that extraordinary.”
June 2006 was 13th warmest since 1901. August on the other hand was a degree cooler than the norm 1971-2000.
Summer 2006 became number three hottest, after 1947 and 2003.
“According to GISS data for de Bilt (I’m using the homogenized data now), the following are the 11 hottest June-July-August periods:
1947
1911
1935
1976
2003
1933
1939
1941
1983
2006”
According to our data (also with GISS, which has three different records by de Bilt) the 11 hottest summers were:
1947
2003
2006
1976
1983
1995
1994
1997
1992
1911
1975.
The only normal summer of ‘this century’, the year doesn’t even belong to it, is 2000.
The coolest summer this century ranks 39th since 1901.
“And according to the even more “homogenized” (i.e. upwards trended…) dutch data posted above, 1947 also had higher max temp than 2006.”
No, the highest absolute maxtemp and the July average were both above 1947. The pair June – July as well.
“So please, don’t conclude anything about climate from one hot summer month…”
I didn’t, read my post and please don’t put contentions in my mouth. I just said July 2006 was vastly extremely hot and this heat was real. Needed no thermometer to confirm that. If I wanted to show climate change, I would not take one month but a lot of numbers. The result is clear, though.
http://nlweer.com/img/17sep2006.PNG
I drink Homogenized milk
I wrote: “And according to the even more “homogenized” (i.e. upwards trended…) dutch data posted above, 1947 also had higher max temp than 2006.”
RR Kampen responded: “No, the highest absolute maxtemp and the July average were both above 1947. The pair June – July as well.”
Let me clarify: When I wrote “dutch data above”, I meant:
http://www.mscha.org/knmi/summer.cgi?station=260&sort=year&month=-1&columns=more
– which shows a max of 36.8 for 1947 and 35.7 for 2006.
Do I understand correctly:
RR Kampen IS a emloyee of KNMI?
And there are THREE different set of records by KNMI at GISS? Why?
And summer 1947 WAS warmer in Holland than anything recent?
Re: Espen (05:21:43) ,,What kind of adjustments have been applied to these temperatures?”
No adjustments were applied to the official (non-homogenized) KNMI record. The GHCN contains outdated or plain wrong records of De Bilt, of which I have already notified NOAA through the proper channels. Hopefully an update will be made to the GHCN soon.