55.62732 -3.73624 Met Office CIMO assessed Class 4. Originally Installed 1984, Wind mast relocated from elsewhere 1994. {Image © Copyright Peter Wood and licensed for reuse under this Creative Commons Licence.}
Paul Homewood over at Not a Lot Of People Know That recently did a very good summary of Storm Eowyn and raised questions regarding the location of the Drumalbin site where the highest wind gust speed was recorded.
The issues of uncertain dates of installation and the site nature made me investigate further – my findings were somewhat concerning.
As the above image demonstrates this is a fully equipped main site for the Met Office and not some limited equipment back garden supplementary unit. The overall location map indicates a wide open rural site with no noticeable problems of shading nor extraneous heat sources. The low wall running south east to north west is 14 metres from the screen at its nearest point and unlikely to be an issue. Land use change is often mentioned at rural sites but it does not appear this site is heavily compromised.
I expected this to be a Class 2 site. When Tim Channon reviewed it in 2012 (with additional images supplied by Caz link below) he considered it a possible Class 1 candidate.
https://trigpointing.uk/trigs/view-album.php?t=7500
This raises the question why has the Met Office only scored it a lowly Class 4? More confusion is raised when looking at the site history. There are numerous cryptic remarks in the Archives most notably a relocation.
It is worth considering that the current site is recorded at an elevation of 245 metres amsl whilst the original site was quoted as 227 metres. An 18 metre (60 feet) difference is quite considerable. The coordinates quoted are not precise enough to definitively locate this previous location however the sting here is that from historic aerial imagery it appears the Stevenson Screen has always been at its current location and it was only the wind mast that was moved. It is actually common for instruments to be at separate locations most notably at aviation sites where wind masts are often separate as are barometers. Deeper research or more local knowledge is required (I guarantee the Met Office will not offer assistance) but it appears the anemometer has been moved purposely to a windier position.
Grid Reference finder suggests this below as the location which whilst around buildings would not preclude a 10 metre wind mast.
The ordnance survey sheet indicates this point sits between the 225 and 230 metre contour and would conform with the quoted elevation which is measured to the base of the mast.
The marking down to Class 4 of the site for temperature and humidity is quite possibly a reflection of the old Met Office siting guidance rather than the modern CIMO standard.
It seems quite possible that the Met Office (in days of greater integrity) originally avoided the wind mast being at the “Top of a hill or steep escarpment where winds will be unrepresentative of the wider area.” under the old classification system and later relocated it to chase records. Whilst that may seem a cynical remark, it has become highly noticeable that the Met Office now regularly predicts where they expect records to be set or broken and subsequently, almost miraculously, achieve the prediction. The 2019 Cambridge and 2022 Coningsby temperature “records” were both almost set up before the event as was the failed Floors Castle 2022 Scottish “almost” record and the Hawarden Airport record breaking relocation
Perhaps the irony of all this is that for accuracy of temperature recordings this site is probably much better than it is being credited for and is certainly much better than the likes of Class 3 Heathrow. Overall though it does look like a suspiciously “engineered” one.
via Tallbloke’s Talkshop
January 28, 2025 at 02:58AM
Iowa Climate Science Education 