50.82840 -4.54592 Met Office Assessed CIMO Class 3 and Satisfactory (Elevation 15 metres) Installed 1/1/1911
Bude is a long established municipal weather station on the north Cornish coast. The above aerial image suggests an open site free from external heat sources and superficially seems to be a good location. However, the Met Office themselves only rate it as CIMO Class 3 (potential inaccuracy due to siting of 1°C) – on further investigation even that looks rather optimistic. I am again indebted to Phil Marshall for excellent site photography that brings into focus issues not otherwise immediately obvious.
Bude is regularly credited as a national and regional high temperature point (dramatically described as “Extremes” by the Met Office ) as always with no reference to potential inaccuracy.
So what are the issues with this site? Well the clue is in Phil’s image below.
How come the view looks down onto the roofs of two story buildings just a short distance away? Because the site is atop a 15 metre high artificial mound above the almost sea level surroundings. The road level street view image indicates the steepness of the slope – the flagpole marks the weather station.
A different angle confirms the unnatural and unrepresentative nature of the site.
All of this appears to be a question of interpretation of the relevant CIMO rules. Sites should be, where at all possible, flat. Whilst the top of the mound probably is flat, as can be seen from another of Phil’s images below it is only just level in the site compound with sloping ground on all sides. The grass level within the compound is also reaching questionable levels of maintenance.
Quite exactly what effects this artificial mound has on airflows and consequent temperature records is open to debate, however, I doubt the Met Office would accept the data if this was a private weather station. Whether it meets Class 3 is highly debatable and the Met Office’s own assessment procedure states
” The ideal site should be on level ground with no trees, buildings or steep ground nearby that might influence the measurements.” (My emphasis)
Proclaiming national “Extremes” for such a site rather seems to fly in the face of observational integrity and smacks more of click bait for attention grabbing “extreme” headlines.
via Tallbloke’s Talkshop
October 17, 2024 at 05:25AM
Iowa Climate Science Education 