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:
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.
* 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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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.
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
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.
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.
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.
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.
bit chilly in those days.
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.)”
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
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
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.
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.
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.
Reply to Lance Wallace ==> Terrific detective work on Humboldt’s COSMOS. “Cold days” indeed. Very well done, sir. Thank you.
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?
Reply to Mike Wryly ==> Amem! Certainly more able than I.
What was the site of these measurements? A hill? A tower? It would be incredible if they did 2 m temperature back then too.
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.
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.
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.
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