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)
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
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
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.
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.
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?
Mike Wryley says:
February 23, 2014 at 7:25 am
QED. I suggest “thence”, possibly “whence”, or “since then” instead of “hence”.
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.
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.
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
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.
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.
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.
Reply to Stacey ==> Thank you for the the link to Manley’s paper on Central England temperatures and urbanization.
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..
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.
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.
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).
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?
A 31 day average max of 11F on one day in June and July in London seems remarkable to me.
Sorry, that should be a 35 year average.
[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]
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?
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/