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
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
This just in: ReallywrongClimate has declared that this mistake “doesn’t matter”…..
Meteo Consult (The other, privately funded) meteorological institute in the Netherlands originally came up with the story (can be found here, in Dutch though):
http://www.weer.nl/nl/home/weer/weer_in_het_nieuws/weernieuws/archive/2009/september/ch/ce28e4a799/article/knmi_verplaatst_thermometer_stilletjes.html
because a lot of us were puzzled, to say the least, that EHDB had been more in line with the stations in the southeast of the Netherlands on hot days than what should be expected. And we were just as puzzled when EHDB was not this summer.
Turns out that the staff had undertaken research because they had noticed that effect as well (turned out to be +0.28C on average, and up to +0.5-+0.7C during hot days), and quietly moved their thermometer to a site that complied with WMO standards. Another side effect of this move is that the average night time temperatures nowadays are warmer than they used to be, because the old, more sheltered location gave an average deviation of -0.48C. All together, the old location was on average -0.15C colder than the new one, that complies with WMO standards.
The only thing that KNMI messed up with in this entire episode is that they did not sent out a press report concerning this move, allowing the tabloid media in the Netherlands to make their own story off of it.
Clint Hotvedt,
Bsc student Earth Sciences,
VU Amsterdam.
Is anybody else noticing a theme lately where otherwise “alarmist” institutions (I’m looking at you BBC, Guardian), are publishing articles that convey a sense of “Maybe it’s not as bad as we thought”.
Don’t get me wrong, there’s still an awful lot of cant being published, but I’m noticing a definite amelioration. I wonder if they’re starting to reposition themselves in light of new realities.
Do these people and organizations that take care of these weather stations ever make ‘mistakes’ that end up with a negative bias?
If that photo shows how one of their sites looks, is this the old met. site which is very close to the KNMI premises?
52.099119° 5.176728°
If so, as usual, these professionals never give accurate co-ordinate information.
Anthony,
This proves a lot of people are carefully reading your site.
I think it is wonderful you have a large and attentive audience.
There is a price: people want errors fixed.
And you fix them, unlike other sites.
I forgive you for confusing Dutch with Danes.
But will I find it in my heart to forgive if you were to confuse Colorado with Texas? Or worse, California?
LOL
In my World Weather Records book 1941-1950, under the station notes for DeBilt temperature it says “in order to reduce means of 1/3(8+14+19hr) to means of 24 hours, the following corrections should be applied:” then it lists corrections of from -0.3C for Dec. and Jan. to -1.8C for June. Then it says that “these corrections are based on the means of the period 1901-1930.” I have often wondered if all these corrections from when records were in hard copy were correctly accounted for when the records were put on line. The temperature drop for the year was -1.1C after the adjustment–it seems odd the adjustment happened the same time as the big drop in the graph above.
I sent the Met Office a questioning email last week, they have just posted this article on their climate change section. Perhaps a tipping point has been reached but not in the way you might think!!
A Pause in Arctic’s melting trend — Met Office response
23 September 2009
Met Office response to American research which has found that the Arctic sea-ice melt has not been as profound as in the last two years:
“The extent of Arctic sea ice has been decreasing since the late 1970s. In 2007 it decreased dramatically in a single year, reaching an all-time low. At the time it was widely reported that this was caused by man-made climate change and that the rate of decline of summer sea ice was increasing.
“Subsequent analysis has shown that this minimum was due, in part, to unusual weather patterns. Arctic weather systems are highly variable year on year and the prevailing winds can enhance, or oppose, the southward flow of ice into the Atlantic. Consequently, the sea ice has not declined every year, but has shown considerable variability.
“The high variability has made it difficult to attribute the observed trend to man-made emissions of greenhouse gases, although there is now enough data to detect a human signal in the 30-year trend. The trend and observed variability, including the minimum extent observed in 2007, is consistent with climate modelling from the Met Office.
“The climate model shows that ice invariably recovers from extreme events and that the long-term trend of reduction is robust, with the first ice-free summer between 2060 and 2080. However, about half of the climate models involved in the IPCC fourth assessment report, show that ice declines in steps — failing to recover from extreme years. The observed temporary recovery from the 2007 minimum in 2008 and 2009 indicates that the Arctic ice has not yet reached a tipping point, if such exists. We expect Arctic ice to continue to decline in line with increasing global temperatures. If the rate of global temperature rise increases then so will the rate of Arctic sea-ice decline.”
Americans + Geography = total mess.
Unfortunately both KNMI and Meteo Consult enjoy their ride on the AGW gravy train spewing AGW propaganda en mass.
I had the same problem, except wind was described as the problem and not shadow. One possibility is that blocking the wind was allowing the still air to warm more than the surrounding air. There are probably other identifiable effects but the known effects should have been taken into account when the siting rules were created.
No, they don’t. Anything that comes out which does not support the current meme of AGW gets “adjusted” before publication.
“The only thing that KNMI messed up with in this entire episode is that they did not sent out a press report concerning this move, allowing the tabloid media in the Netherlands to make their own story off of it.”
Is this the same KNMI that allowed the tabloid media to vent their warming hysteria?
There is lots of talk about how bad GISS is, and how it negatively affects NASA reputation and that change is needed. I think that the folks at GISS and their liberal masters are getting exactly what they want. They have control of the data, and a “connection” to NASA that gives them an aura of respectability. The desired outcome of the product that GISS produces is “PROOF” of AGW. This is not a scientific operation, it is a political one. The fact the GISS is in NASA has no bearing on what GISS is doing. Their goal is not rocket science. The goal is to further the political agenda of the Left.
isn’t this all moot?
I thought that the correction algorithms are so reliable that we are phasing out actual measurements because we don’t really need them anymore.
Anthony,
Not sure I quite get your point with the comparison to Essen. I resized and overlayed the Essen graph onto DeBilt, and they actually do show good agreement.
Graphic here.
http://www.prclaser.com/images/debiltvsessen.jpg
Are you trying to make the point that the more recent high temps have caused Giss to adjust down the past temps at DeBilt??
George Tobin (11:56:16) :
I thought that the correction algorithms are so reliable that we are phasing out actual measurements because we don’t really need them anymore.
—-
No, no, no.
You have it all backwards.
The MODELS are so good that we don’t need to collect observational data. It is obvious that if there is any discrepancy between the models and reality, that there must be something wrong with the instruments.
Robert M. (11:46:07) :
Fine. I’m sure the argument can be made to increase NASA’s budget at the expense of a disposable institution.
You heard the President: We are going to seek out those institutions that aren’t working and eliminate them.
I’m much rather see NASA have what they need for space stuff.
My favorite quote of the month!!!!
Heck, out here, they don’t look at instruments OR out the window for weather forecasts… it seems they just try to guess based on historical averages. Which would be why yesterday’s record high (by 3C !!!) was a total shock to those whose job it is to guess…. er, forecast.
And hey, everyone knows that 30 years is “enough” for historical averages, right?
I just found a copy of “World Weather Records” online at archive dot org–sorry I don’t know how to make links but you can find it by googling. The fact that the temperature shoots up again about 1990 really looks fishy; like corrections were applied incorrectly then later corrected? If you would like to see the publications history and provenance of “World Weather Records” google global change master directory DSI-9644 –it’s eye opening. When these records were put online or digitized, I expect it was done by some poor little GS-2 who may not have any idea what a correction meant or how it was done.
Interesting article illustrating how a faulty station can play havoc with the records.
As I don’t like the concept of ‘global temperatures I tend to use national temperature data sets-the older the better. The Dutch ones go back (sporadically) about as far as CET.
I thought it would be an interesting exercise to try and smooth out the short term temperature trends that will make someone in their 30’s today say-‘it’s got warmer in my lifetime’- a point which their great grandparents might disagree with, having lived through the 1920’s and 30’s
Consequently I decided to see what temperature a person living a three score year and ten life span in England would experience (using CET to 1660)
This table is based on the average annual mean temperature enjoyed by the ‘British Everyman’ through each year of each decade. This assumed he was born at the start of a decade and died the last year of the decade seventy years later. These are the calculations;
Someone born in Britain in 1660 and living to 70- Average annual temp 8.87c
Someone born in 1670 and living to 70 Average annual temp 8.98
1680 9.01
1690 9.05
1700 9.19
1710 9.21
1720 9.17
1730 9.14
1740 9.04
1750 9.03
1760 9.08
1770 9.10
1780 9.07
1790 9.12
1800 9.15
1810 9.13
1820 9.14
1830 9.12
1840 9.10
1850 9.14 (Start of the famously reliable Hadley global temperatures)
1860 9.17
1870 9.21
1880 9.30 Official end of the Little Ice Age-Start of GISS
1890 9.39
1900 9.40
1910 9.46
1920 9.497
1930 9.60
1940 9.70 (projected to 2009)
1950 9.76 Extrapolating current trends (our favourite phrase)
1960 9.79 Using advanced modelling techniques to create a robust scenario.
I called the people born in the period from 1660 to 1880 ‘LIA Everyman’ in as much the person lived part or all of their lives during the little ice age. Those born born from 1890 to the present day I have termed ‘UHI Everyman’ for obvious reasons. No adjustments have been made to correct UHI, poor siting, change of instruments etc.
The depths of the LIA can be clearly seen, but what I find interesting is that temperatures have risen only some 0.6 degree C since the warmest period of the LIA, which does not suggest a runaway climate change scenario to me.
(The slightly cooler average temperatures in the LIA are primarily due to colder winters – summers were pretty similar)
Of course, were it possible, it would be most interesting to extrapolate this back to the MWP and Roman optimums, as it would put todays very modest rises into a proper perspective.
My main point is whether anyone else living in a country with long records-Holland, Denmark, Sweden etc, would care to compile a similar chart on the same basis, that smooths out the short term noise.
tonyb
Is our RR Kampen not a Dutch meteorologist? Where is he when he is needed? Can he be prodded to come out of the woods?
(I just hope he does not work at KNMI)
a reader 12 47 19
Here is the explanation for the temperature increase since 1990-it is to do with the impossibility of constructing a meaningful global temperature
Link 1 Wikipedia’s explanation of global temperature with a colour globe showing location of weather stations world wide.
http://en.wikipedia.org/wiki/File:GHCN_Temperature_Stations.png
Link 2 Even better explanation with graphs
http://www.appinsys.com/GlobalWarming/GW_Part2_GlobalTempMeasure.htm
Link 3 This piece is taken from link 2 and is a blink chart illustrating station change
http://climate.geog.udel.edu/~climate/html_pages/air_ts2.html
(go to first item- ‘stations locations’ and click) You will get a media player animation illustrating the ever changing location and number of weather stations from 1950. Look for the startling changes since 1990.
These are primarily due to vast numbers of ‘cold’ stations being withdrawn in Russia following the end of the approriately named cold war.
tonyb
In Norway I have noticed some places that the area under the white boxes where they measure temperature is “environmentaly” a disaster area with very little green, but instead loads of brown.
Strange?
MattN,
Mistakes never matter to RC or members of the ‘Team’. Even the “hockey stick” mistake is now deemed unimportant and it is time’to move on’.
They are on a mission and mistakes don’t alter that.