Historical Note: Greenwich, England Mean Temperature, 35-yr Daily Averages 1815-1849

Guest Essay by Kip Hansen

While researching for a future essay tentatively titled “Whither Original Measurement Error?”, I have been reading up on the origins of the modern meteorological thermometer. Fascinating stuff, those early scientific instrument makers and their creativity and engineering skills.

I came across an interesting little [e]book that was just the sort of thing I was looking for, written by John Henry Belville in 1850, who started work at the Royal Observatory, Greenwich, Kent, England, in 1811 as a meteorologist and was still at it 35 years later. Here I reproduce the Title Page and Preface from his book:

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Included in this little volume is the following chart, which I offer here without comment for those interested in the fascinating study of the long-term Central England temperature record. This thirty-five year average, day by day, is fairly well guaranteed not to have been adjusted or modified in any way since its publication in 1850 and might have some use for comparison purposes.

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* Concerning the decrease of the mean daily temperature from the 12th to the 14th of May, see Humboldt’s ‘Cosmos,’, vol. i. page 121. Bohn’s edition.

The small note under the chart was included in the book.  It refers to something in the great tome: Humboldt’s COSMOS; or a  Sketch of a Physical Description of the Universe.   Copies are available online, but I was not able to trace the exact reference.

The full Belville book is available to read online free – albeit through Google Play’s eBook app — at:

http://books.google.com/ebooks/app#reader/9L0ZAAAAYAAJ

It is a rather stiffly worded, but enjoyable, trip into the scientific past.

# # #

Moderation Note: I would appreciate links from [any reader] to good sources for historical sources of information on expected measurement errors of meteorological thermometers in use from 1850 to present, including narrative sources of “operator error”. (Example: Several years ago, I did a Surface Station Project interview in Santo Domingo, Dominican Republic, in Spanish, on how the Stevenson Screen thermometers were read there. Acceptable expected error according to the Chief Meteorologist? +/- 1 °C)

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Mike Wryley

Compact prose it is not, but the average educated person of the 1800s appears more able to put a coherent sentence together than his brethren 200 years hence.

Ian L. McQueen

Minor correction to moderator: plurals are not made with an apostrophe, like “reader’s”, above. (Possible exception: Australia; when I lived there in the 70s I got the impression that one could not become a professional signmaker, as in window signs, unless one DID use apostrophes.)
This is a VERY common practice, but should be avoided at all times.
Ian M

William Abbott

Thanks for posting this. I share your interest in weather and climate history. Don’t hesitate to post again. I’m going to take a look at the book tomorrow.

bernie1815

If the weather station was at the Greenwich Observatory, then it is in a relatively open area – part of the Royal Park – at the top of an old flood plain of the Thames – probably 200′ above sea level. There is a cluster of buildings around the Observatory so some local man-made impact is possible. It is unclear whether at earlier times there were additional buildings at the location. It is a beautiful area. I went to school in nearby Blackheath and our cross country runs included the nasty slopes to the left and right of the Observatory. The views of London from the Observatory and General Wolfe’s statue are spectacular.

a reader

Google play also has very early daily obs. for cities in the US, for instance Providence, RI. You can simply search forSmithsonion Contributions to Knowledge and meteorology and an assortment will come up. These are not the same records as are in World Weather Records summary books, but are the source records.

The errors introduced by the Stevenson screen itself is something that is worthy of evaluation.
It was a consistent standard for a long time, which is good. However, even in perfect order as screen will not totally isolate the thermometer from solar heating on a clear day, especially one with little wind.
There will be a small afternoon warming bias that will be function of sun-hours (clear sky conditions) and wind speed, ie not climate neutral.
Once the screens have degraded ( see surfacestations.org) the situation gets much worse, leading to an age (time) related bias.
We now have largely moved to pokey little plastic shielded thermistors which IMO are even more prone to an afternoon bias.

G P Hanner

That’s an interesting set of temperature means. For one thing, they are clearly measured in degrees Fahrenheit; for another, the summer temperatures are over ten degrees cooler than they were when I lived in England (East Anglia) in the early 1980s. Those averages do not reach 70 degrees, while in the early 1980s temperatures in well into the 70s were pretty common. When the temperature hit 80 or more the Brits were complaining that it was a hot day.

Time degradation leads to another problem when those who control the data start “homogenisation” . A Stevenson screen wiil degrade over time leaving a warming bias. However, when it gets restored or replaced, it will likely cause a dislocation in the record when compared to surrounding station data. This will lead ‘homogenisors’ to conclude an error in the data and “correct” the cooling by introducing an adjustment.
That station record gets a few tenths of a degree bump and starts degrading all over again.
When a neighbouring station gets cleaned, the same happens. Thus the whole record gets homogenised up.
Time to get back to REAL unpasteurised data , accepting its uncertainties, and realistic uncertainty estimations.
Speculative “corrections” do not reduce data uncertainty , they increase it.

richard

bit chilly in those days.

Lance Wallace

I may have found the reference in Cosmos regarding the depression of the temperature on May 12-14. (Although it seems to me the “depression” occurs on May 9 and 14).
I downloaded one version of Cosmos from the gutenberg site http://www.gutenberg.org/ebooks/14565
On p. 133, von Humboldt refers to a depression in temperature on the 12th of May associated with the November asteroids (?):
“Since the period that streams of meteoric shooting stars were first considered with reference to the direction of their orbit as a closed ring, the epochs of these mysterious celestial phenomena have been observed to present a remarkable connection with the regular recurrence of swarms of shooting stars Adolph Erman has evinced great acuteness of mind in his accurate investigation of the facts hitherto observed on this subject, and his researches have enabled him to discover the connection of the sun’s conjunction with the August asteroids on the 7th of February, and with the November asteroids on the 12th of May, the latter period corresponding with the days of 
St. Mamert (May 11th), St. Pancras (May 12th), and St. Servatius (May 13th), which according to popular belief, were accounted “cold days.”*
[footnote] Adolph Erman, in Poggend., Annalen, 1839, bd. xlviii., s. 582-601. Biot had previously thrown doubt regarding the probability of the November stream reappearing in the beginning of May (Comptes Rendus, 1836, t. ii., p. 670). Mädler has examined the mean depression of temperature on the three ill-named days of May by Berlin observations for eighty-six years (Verhandl. des Vereins zur Bedförd, des Gartenbaues, 1834, s. 377), and found a retrogression of temperature amounting to 2.2 degrees Fahr. from the 11th to the 13th of May, a period at which nearly the most rapid advance of heat takes place. It is much to be desired that this phenomenon of depressed temperature, which some have felt inclined to attribute to the melting of the ice in the northeast of Europe, should be also investigated in very remote spots, as in America, or in the southern hemisphere. (Comp. Bull. de l’Acad. Imp. de St. Pétersbourg, 1843, t. i., No. 4.)”

William Cox

As with most books.google.com ebooks, the book is available in a variety of formats, not just their eBook format.
Go to the “eBook Free” red box and hover; then click on PDF (or whatever format you want usually including PDF and HTML, and often other formats.
I downloaded the PDF (from scanned images) in this manner, and ran Adobe Acrobat Professional’s OCR on the text for easier searching and (e.g.) table copying.
Search for the author + title words and you find http://books.google.com/books?id=uzVWAAAAcAAJ&pg=PP7&dq=John+Henry+Belville+meteorological+instrument&hl=en&sa=X&ei=Px0KU46IE_OFyQHq9oHABw&ved=0CDsQ6AEwAQ#v=onepage&q=John%20Henry%20Belville%20meteorological%20instrument&f=false

Kip Hansen

Reply to McQueen ==> Quite right , sir! Dashed this note off without the benefit of my better half and English grad editor. I know all these rules but by old fingers and eyes neither remember to type them nor catch them in my own editing.
[There are very subtle differences between asking “readers” “any reader” and “all readers” to do something that editors and writers need to agree on, but lettuce not be too picky while choosing how to right a grammatical wrong. Mod]

G P Hanner says:
February 23, 2014 at 8:00 am

That’s an interesting set of temperature means. For one thing, they are clearly measured in degrees Fahrenheit; for another, the summer temperatures are over ten degrees cooler than they were when I lived in England (East Anglia) in the early 1980s. Those averages do not reach 70 degrees, while in the early 1980s temperatures in well into the 70s were pretty common. When the temperature hit 80 or more the Brits were complaining that it was a hot day.

Being “mean daily temperatures” they are likely the average of the low and high temperature, or probably morning and afternoon temperature.
I dare say that Brits would complain loudly on days where the average temperature is 80°F.

Elliott M. Althouse

GP Hanner- The average summer average in London peaks at about 63.5 F. I believe you are referring to high temperatures, these are averages of high and low. Last 30 year average for London is high 71 low 56 in mid July.

Elliott M. Althouse

The current London temperatures are only on average 0.6 C. higher in summer now than then, according to these observations. How accurate were the thermometers used then?

Seems to be measuring the last years of the ittle Ice Age.

Kip Hansen

Reply to Lance Wallace ==> Terrific detective work on Humboldt’s COSMOS. “Cold days” indeed. Very well done, sir. Thank you.

Kip Hansen

Reply to Greg Goodman [x2] ==> Thanks for your helpful input on errors introduced in the normal course of events in the use of Stevenson Screens.

@bernie1815
That wouldn’t be the ‘Blackwall Tunnel run’ from a school on Lee Terrace by any chance?

Kip Hansen

Reply to Mike Wryly ==> Amem! Certainly more able than I.

JDN

What was the site of these measurements? A hill? A tower? It would be incredible if they did 2 m temperature back then too.

bernie1815

James: It certainly was!! I was there from 1960-1968. Bros Vincent, Alban, Richard, Leo, etc. Alas they pulled it down 3 or 4 years ago. In a strange twist of fate and time, after growing up in Massachusetts, my daughter lives next to the Park.

Pat Frank

I’ve published two papers in E&E on systematic error in the surface air temperature record; the first here (869.8 KB pdf), and the second here (1 MB pdf). I’ve most of the work done for two more.

sonofametman

My father worked as an observer and forecaster for the UK Met Office for his entire career. He spent 6 years on weatherships in the North Atlantic in the 1950’s. He was concerned that the sea surface and air temperature measurements were affected by things like evaporative cooling of water samples and heat radiation from the vessel (converted naval corvettes). He wanted to do some experiments to try and eliminate these sorts of errors by improving the methods, so he wrote to the top brass, but was ignored. The errors in these measurements will be all over the place depending on the season and the weather.

Barry Cullen

I don’t know if this has been pointed out yet but these “chilly” temperatures were measured towards the end of the last LIA and are therefore to be expected.
BC

Keith Willshaw

JDN Asked
> What was the site of these measurements? A hill? A tower?
> It would be incredible if they did 2 m temperature back then too.
The Greenwich Royal Observatory which is on a low hill east of London close to the River Thames
Location 51.476864,-0.000491
Google maps shows it jut fine.
Keith

Stephen Richards

bernie1815 says:
February 23, 2014 at 7:36 am
Greenwich at that time was a small country village. I don’t know yet when the naval academe was built (but it must be on the web) because a lot of naval activity was focused at Portsmouth.

Stephen Richards

Elliott M. Althouse says:
February 23, 2014 at 8:50 am
The current London temperatures are only on average 0.6 C. higher in summer now than then, according to these observations. How accurate were the thermometers used then?
The thermometer were as accurate as any modern Mercury instrument but the reading may have been suspect. I was trained as a boy to read them (took about 3 minutes) but you can misread quite easily if you are not concentrating on your position relative to the thermometer.

@bernie1815 Well, what a small world!
I was there 1971-79. Of those names you mentioned only Brother Richard is familiar to me. He was my form teacher for (part of) the second year and taught me Latin.
My U6 year was the first year of a comprehensive intake. At the same time it went from three-form entry to four-form. Given how crowed things already were, that cannot have helped with the transition. The sixth-form was lost a long time ago (late 80s?) and it continued going downhill.
Under the Academies programme, it (together with a neaby primary school) was replaced by a newly built school called St Matthew Academy which was built on The Cerdars and opened in 2007. The SJA buildings were demolished after then.

bernie1815

JBD – though that can hardly be your real name unless your parents had a strange sense of humour and read SF Comics. I suspect that Bob Mellish was still there, along with Chief and John Hillier. Many of my teachers were getting close to retirement at the time I left. Was Mick Sheridan there at that time? He was a classmate.
Are you still in the UK or in the States?

Hoser

Mike Wryley says:
February 23, 2014 at 7:25 am

QED. I suggest “thence”, possibly “whence”, or “since then” instead of “hence”.

Kip Hansen

Reply to Pat Frank ==> Thank you for the two E&E papers. I have been puzzled for the last several years by the lack of any real acknowledgement of original measurement error when the world is in a panic over changes as small as .5°C, which fall well within known likely error in gross measurement error. Time will tell. Thank you.

… He wanted to do some experiments to try and eliminate these sorts of errors by improving the methods, so he wrote to the top brass, but was ignored. The errors in these measurements will be all over the place depending on the season and the weather.

I dare say that there is much error in all our weather data sets and that is without the outright fraud of the government data sets of modern times. But then someone once said you go to war with the data set you have and not the one that you wish you had.

Mods.
And another short post goes to moderation. Please look for it.

Stacey

Kip
The following link is to Professor Manleys paper on the CET. It may be of interest and actually he discusses the effect of urbanisation in temperature records.
http://www.rmets.org.uk/sites/default/files/qj74manley.pdf

Nigel S

Royal Naval College, Greenwich was built as the Royal Hospital for Seamen from 1696 to 1712 and designed by Sir Christopher Wren who also designed the Royal Observatory ‘for the Observator’s habitation & a little for Pompe’. Other gems there include The Queen’s House, 1616 by Inigo Jones. Greenwich has been quite built up for at least 300 years.

Elliott M. Althouse

Sir Christopher Wren designed the original building at The College of William and Mary in Williamsburg, Virginia. It was completed in 1693 when the college began its charter. There are a couple of photos on the college website, wm.edu if anyone is interested. William and Mary was the first chartered college in the U.S., although Harvard managed to begin functioning sooner by one year. Williamsburg was the colonial capital of Virginia.

bernie1815

Nigel: The cluster of buildings remains stunning. The question I have is whether the thermometer was moved and if buildings and/or walls were added or removed during the period. A few feet can also mean a change of 10 feet or more in altitude. My recollection is that there are small courtyards and enclosed areas, currently facing North. I think what may have been the living quarters face South away from the Thames.

Kip Hansen

Reply to Stacey ==> Thank you for the the link to Manley’s paper on Central England temperatures and urbanization.

Kip Hansen

Reply to Stephen Richards and Elliott M. Althouse ==> If they were using Six’s Max-Min thermometers, the original records I am researching list them as “troublesome” and less accurate than could be desired without careful calibration against a known standard. Stephen, are you saying that you received training on reading these? I know there were some museum pieces still around and in use. I’d be fascinated to read your narrative description of the method of reading them correctly.

If Maximum recording thermometers were not used back then, these temps all need to be either compared to recordings of the same method or be adjusted UP by an amount that is perhaps greater than the claimed warming since then..

YorkshireChris

There was a paper published in the (UK) “Meteorological Magazine”, vol 106, 1977, by Joyce Laing that looked at temperature records in the UK. This confirms that the temperatures at the Greenwich Royal Observatory were recorded from 1841 in a “Glaisher Stand”, introduced by James Glaisher, the Superintendent at the Observatory. The stand was a vertical board 4 feet above the ground, on which the thermometers were mounted, sheltered from above. The stand was rotated on a central pivot so that the thermometers were always shaded from the sun, but this depended on the conscientiousness of the observers.
In 1863 Thomas Stevenson designed the louvred “Stevenson Screen”, but this was not used at Greenwich for many years. There was a debate through the 19th Century about which type of screen gave the most accurate results for air temperature and a test was organised by J.G Symons (of British Rainfall fame) at Strathfield Turgiss, Hampshire, in 1868-70. Following these experiments the UK Meteorological Office recommended the use of Stevenson’s Screen as the standard screen in the UK. However, at the Greenwich Observatory the Glaisher Stand continued to be used until 1938, to preserve the homogeneous record. A Stevenson Screen was in place at the observatory from about 1900, but the readings from it were not published and the Glaisher Stand was only replaced as the formal recording location in 1938.
The comparisons of the screens found that, in summer, often the Stevenson Screen recorded maxima about 1F lower than in the Glaisher Stand, although on some days the difference was as much as 3F. The Met Office no longer now appears to use the temperatures recorded at Greenwich in the Glaisher Stand in the historical record, so the 100F recorded on 9 August 1911 at Greenwich is no longer regarded as almost the highest temperature in the UK. The suggestion is an equivalent Stevenson Screen temperature on that date would have been 96.6F.

bernie1815

One other commentary on the location of this station. The Observatory is close to a thickly settled area down by the river and to the West. This may be important because when Londoners used to depend almost exclusively on coal for warmth during the winter, the chances of smog were pretty high. Growing up in the 60s, there would be dense fog/smog to the South of the Observatory during the winter months sometimes lasting for days. It was so bad it was faster many times for me to walk home over Shooters Hill rather than stay on the bus. Obviously such local man-made weather conditions can play havoc with the temperature records. The replacement of coal by natural gas, better emission controls and the movement of industry out of London have all served to dramatically reduce the incidence of fog and increase sunlight compared to the 60s at least.

YorkshireChris

Further to my previous post, it would appear that the thermometers used at Greenwich were comparable to the standard maximum and minimum thermometers used in current times and certainly not the “Six’s” pattern of thermometer.

@bernie1815
Let’s not clutter this thread anymore. You can contact me at ugimill-0223 at yahoo.co.uk (squish).

Jim Jelinski

Hello to all.
I have a question on the Stevenson screen coatings.
My understanding is that for many years they were coated with whitewash, which would ‘wash off’ and expose a new, clean white surface with each rain.
My understanding is that at some point the coating was changed to white latex paint.
I know that in my local (Gulf South) climate, mildew often grows on latex paint, sometimes ‘white’ surfaces turn a color pretty close to black. This of course increases the heat absorption. The effect is probably not as pronounced in cooler, less humid climates.
My question is this:
How do ‘whitewashed’ Stevenson screens compare to white latex painted Stevenson screens?
What is the effect of the change in coatings on the temperature readings?
What is the typical effect on the heat absorption of the coating due to mildew, dust accumulation and aging of the latex paint compared to whitewash?
Have any experiments or studies been done to examine the possible effect on temperature readings resulting from the change in coatings?

Robtin

A 31 day average max of 11F on one day in June and July in London seems remarkable to me.

Robtin

Sorry, that should be a 35 year average.

Mike McMillan

[There are very subtle differences between asking “readers” “any reader” and “all readers” to do something that editors and writers need to agree on, but lettuce not be too picky while choosing how to right a grammatical wrong. Mod]
You need a comma between ‘readers’ and ‘any reader.’
A comma should also go between ‘any reader’ and ‘and.’
[The writer of a right correction to the moderator’s written righting of a previous writer’s righting of an earlier writer’s right to write readers rightly or wrongly should understand that the moderator’s right to write rightly about previous writers’ rewriting rightly or wrongly is not rightly wound around the right writers’ right to write wrongly. Mod]

Louis

If +/- 1 °C is an “acceptable expected error” for a surface station, then isn’t the estimated global warming over the past century of 0.8 degrees within the margin of error?

Mike McMillan

Jim Jelinski says: February 23, 2014 at 2:54 pm
You’re new here, right?
The difference between whitewash and latex was how this whole blog and the Surface Stations project got started.
http://wattsupwiththat.com/about-wuwt/faqs/