Ooops, Dutch Meteorological Institute caught in weather station siting failure – moved station and told nobody

KNMI has been measuring the wrong temperature for years

debilt_newspaper

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

DE BILT – Weather Institute KNMI has been measuring the years incorrect temperatures on its grounds in De Bilt due to an incorrect setup of a thermometer.

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

KNMI-DeBilt_GISS

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:

De-Bilt-metadata

Checking some nearby stations in GISS, click for source data:

KNMI_nearby_stations

The GISS plot for Maastricht Airport:

Maastricth_station_GISS

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:

ESSEN_station_GISS

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) …

http://www.wmo.ch/pages/prog/www/IMOP/publications/CIMO-Guide/Draft%207th%20edition/Part1-Ch01FINAL_Corr.pdf

http://www.wmo.ch/pages/prog/www/IMOP/publications/CIMO-Guide/Draft%207th%20edition/Part1-Ch02Final.pdf

… 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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Gene Nemetz

the only station in the Netherlands used for GISTEMP
James Hansen is pathetic!

Rhys Jaggar

So a mere siting issue for a thermometer can give rise to a half degree error?
And what is the ‘runaway’ figure for global warming again?
0.6 degrees?

Dr. Cornelius, P Eng.

You obviously mean the DUTCH, not Danish Met Institute.
[Fixed, thanks. ~dbs, mod.]

Well, we all like WUWT to be precise and eloquent. So please, change “Danish” in the header for “Dutch”.
I read most amusing discussion on this subject on a Dutch/ Belgium weather forum. The meteorologist working for KNMI could’t explain why they moved the thermometer: the KNMI officially deny that the measurements were corrupted. The question why they changed the thermometer placement anyway remains unanswered to this day.
We all saw tMax at De Bilt drop, the last half year. Now we know why.

Anthony! We live in the Netherlands, we are Dutch, not Danish
REPLY: Yes my bad, fixed, thank you. – Anthony

Seppie

De Bilt is in Holland, so its Dutch not Danisch meteo institute!!!!!

Michael T

Oops, should the headline read ‘Dutch’, Anthony? When I first read it I thought that all of those lovely danish arctic data were to be thrown into the garbage.
REPLY: Press refresh.

Espen

Dutch, not Danish! You better keep us Europeans apart, or we’ll assume you’re Mexican or Canadian 😉
Anyway, this is very interesting. I commented on the de Bilt station in the comment thread on Lucy’s Arctic article, questioning the quality of the data, and also that GISS actually adds a trend when “homogenizing” the data.
Anyway, one of the posters there commented “I’m 42 and I know the difference between recent years and the seventies/eighties. It is vast.”. Well, I’m 48 and know the difference too – especially the late seventies and late eighties had much colder winters than recent years. I think this claim is very revealing: Most of the researches, activist and politicians promoting the AGW theory are too young to have experienced the 30s and 40s – but they’re also old enough to have experienced the seventies or at least the eighties. So they have actually experienced “global warming”! But they don’t realize that this warming may be part of a natural cycle, and that many places in the world may have been just as warm, or very close to current values, in the 30s and 40s.
Therefore, it’s such a pity that there are so few stations left that actually cover the whole period from the beginning of the 20th century to today, and that so little care is taken to keep these records as continuous and good as possible.
Anyway, I have a hunch that we’re in for an extremely cold 2009/2010 winter. Maybe the Dutch may go skating on their canals again, like they did this January – for the first time in 12 years.
REPLY: PRESS REFRESH PLEASE

Hoi Polloi

Yeah, it’s Dutch and Kopenhagen is the capital of Holland.

Espen

PRESS REFRESH PLEASE
Anthony: Hey, don’t shout, there were no comments yet when I started writing 🙂
If you don’t mind I’d like to repeat something I wrote in the “what hockey stick?” thread:
I tried to find stations with long records in Holland, and found De Bilt (near Utrecht) which shows the same result of homogenization as the arctic cities: The temperatures from 1881 to 2009 first shows a flat trend (-0.05C/century), but after homogenization there’s suddenly a +1C/century trend! For Milano, Italy, it’s even stranger – a -0.7C/century trend is turned into a +0.7/century trend. I.e. the homogenization performs the reverse of an UHI correction, despite the fact that Linate is an airport very close to a huge city!
Notice the part about Milano here. I’m starting to believe that the GISS data for Europe (and probably other parts of the world too) is even worse than what you have discovered in the US with the surfacestations project. And the CRU data we can’t even evaluate…
One interesting exercise one could do, is to have a look at the 2000-2008 versus 1921-1950 anomaly, with 250 km radius:
http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2009&month_last=08&sat=4&sst=0&type=anoms&mean_gen=08&year1=2000&year2=2008&base1=1921&base2=1950&radius=250&pol=reg
I think a lot of the red spots on that map will turn out to be due to really bad data…
REPLY: Not shouting, just trying to get everyone’s attention that keeps pointing out the error in the title. – Anthony

Bob Kutz

Espen (08:02:50) :
Regarding your point about having “actually experienced ‘global warming’!”
I find it really interesting that many of the ‘scientists’ have now taken to adding that there’s no way to account for the swift climatic change only from natural variability, and then proceed to allocate most of the warming to ‘man-man’, anthropogenic, or even “human induced” conditions.
It’s just another twist of terminology to cover their tracks, kind of like the official change of ‘global warming’ into ‘climate change’ when the surface temps refused to go along with their predictions. To me; the fact that they are adding ‘natural variability’ to their lexicon is a solid clue that most of them realize their golden-egg laying goose may eventually be cooked, ironically by a cooling climate!

Joel Heinrich

correct population numbers:
De Bilt: 42,052
Maastricht: 118,355
Essen: 579,759
Uccle: 76,732
Don’t know where Gisstemp get their numbers… Oh, do they “correct” the data according to the population?

Espen

Joel Heinrich: GISS counts Essen as 7.5 millions. The reason is that Essen is in the middle of the Ruhr Area which can be considered one vast metropolitan area (they don’t do this to other similar areas, though, like Frankfurt am Main and surrounding cities, or Ludwigshafen/Mannheim/Heidelberg)

John S.

The step-down seen in the De Bilt record from the 50s through the mid-80s certainly can’t be attributed to proximity to then much-younger trees. Although it looks suspicious, similar cooling was experienced then throughout much of northern Europe, notwithstanding the contrary indication from UHI-affected Essen. It does, however, raise the issue of perhaps other unreported siting changes, which no “homogenization” procedure–least of all the GISS “knee-bend”–can adequately fix. Despite all of this, De Bilt is by no means the most egregiously unreliable record in that region.

Steve S.

What difference does this make when RC is making the daily claims that warming is continuing?
Just look at the recent comments there.
It’s an astounding display of very agressive manipulation by the most arrogant and condescending alarmists around.
IMO this battle must be waged here and in their faces.

The instrument stood too close to a line of trees, due to which on average half a degree (Celsius) too high was measured

Strange. My common sense would have said that if there is a line of trees shadowing the thermometer, this should read lower temperatures, not higher.

Bill Yarber

At least KNMI moved their sensor to comply with standards. Look at all the work Anthony and his helpers have done to show the deplorable state or the US surface stations and NOAA has done next to nothing to correct the numerous problems but found the time to attack Anthony. Hansen and NOAA or totally corrupt when it comes to AGW!

jeroen

The drop in the 50’s is also because the station was moved away from a building. So pre 50’s should be lower. The early forthy’s had a lot of hars winters in a row. essen doesn’t look like the record of the bilt because the see influance is a lot larger in the bilt then essen. So you can’t compare those and say only 150km away. But then again KNMI are true AGW believers.

jeroen

Another thing about the upward trend in the bilt from the 60′ till now. The knmi offcourse blamed AGW but they also noted that there was a lot of extra sunsine in the last years.
http://www.knmi.nl/klimatologie/maand_en_seizoensoverzichten/maand_260_grafiek.html
This link is form this month. You can see the second graph for sunshine.

ared

Also, they changed from a pagode-hut to a Stevenson screen right at the jump in 1950. I’ve heard local specialists say the hut recorded T-max too high, also resulting in elevated T-avg.
Does anyone know how long the thermometer has been at this location? When they changed from Stevenson to digital dish (1993), or was the Stevenson at the same location? When did the difference between Cabauw and De Bilt build up?

Bill Marsh

Always the same line, no matter how many of these poorly sited, suspect stations turn up, they NEVER affect the overall accuracy of the system.

jeroen

They say there is no change in the climate average because they use multiple stations. But these station are too suffering from bias.

h.oldeboom

KNMI is a miserable organisation and a slave of WMO and IPPC; therefore is good to know now how weak their temperature measurement procedures are. In the Netherlands you can better inform yourself about weather when you live in the south by KMI (Belgian weather forecast) or when you live in the north by the Northern German weather service. By the way, about 35 years ago, KNMI transferred a local weather station from the dike (near the sea) in Den Helder
(I lived there) to the local airport. Interesting to know if they realised/administrated then a possible sudden temperaure change.

rbateman

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?
Or can GISS be salvaged with new management?
Budgets are tight, you know.

peter vd berg

fipo 23-09-09 on Tips i want my name also mentioned 😉
peter vd berg (11:34:12) :
This link unfortunately only in dutch
http://www.elsevier.nl/web/Nieuws/Wetenschap/246638/KNMI-meet-jarenlang-foute-temperatuur.htm
shows that the dutch KNMI meteo has been measuring the wrong temperatures for years now.
They’d placed their equipment next to a row of trees and only found out when they moved their equipment and suddenly there was a temperature drop of about 0.5 Celsius on average.
Later comparisons with other weatherstations showed that this fault had been creeping in due to the row of trees growing and retaining heat more.

MattN

This just in: ReallywrongClimate has declared that this mistake “doesn’t matter”…..

Clint Hotvedt

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.

Mark

Do these people and organizations that take care of these weather stations ever make ‘mistakes’ that end up with a negative bias?

Tim Channon

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.

Jack Simmons

REPLY: Not shouting, just trying to get everyone’s attention that keeps pointing out the error in the title. – Anthony

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

a reader

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.

Murray Carpenter

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.”

the_Butcher

Americans + Geography = total mess.

Ron de Haan

Unfortunately both KNMI and Meteo Consult enjoy their ride on the AGW gravy train spewing AGW propaganda en mass.

AnonyMoose

Urederra (09:05:17) :
Strange. My common sense would have said that if there is a line of trees shadowing the thermometer, this should read lower temperatures, not higher.

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.

Mike O

No, they don’t. Anything that comes out which does not support the current meme of AGW gets “adjusted” before publication.

Hoi Polloi

“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?

Robert M.

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.

George Tobin

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.

radar

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??

PSU-EMS-Alum

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.

rbateman

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.

CodeTech

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.

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?

a reader

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

Alexej Buergin

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

Jon

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?

Dave Andrews

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.