Llysdinam DCNN 8304 – A Century of Dubious Data.

52.21571 -3.45166 Met Office Assessed CIMO Class 5 Installed 1/1/1882

The UK press seems preoccupied with filling its pages with any nonsense it can – it seems the Met Office is always willing to provide them with silly enough material.

So what is the reality behind this nonsense?

Firstly this is the “Daily Extremes” that the Met office publishes with LLysdinam as its star performer.

Tim Channon reviewed this site back in 2012 and described it quite bluntly “This site is extraordinarily poor for an AWS” {automatic weather station} He correctly judged it as a Class 5 site (inaccuracy by siting up to 5°C) as the Met Office subsequently assessed. Realistically it should also be judged as suffering from significant shading effects. At the time Tim could not get any close up imagery or further site details, however, that has now changed.

Firstly just to establish the level of hubris displayed by the Met Office, this is what they say about some of their long term sites

“In the UK, the Met Office has a long tradition and expertise in collecting accurate observations to monitor climate and weather.

We manage an extensive network of surface observing stations. Six of these sites, Eskdalemuir, Rothamsted, Balmoral, Armagh, Morpeth (Cockle Park), and Llysdinam, have now been awarded Centennial Station status by the World Meteorological Organization (WMO), recognising their global importance for collecting long records of accurate observations and for providing a unique history of recent climate.”

With the benefit of closer inspection below, I shall be as equally blunt as Tim was – this site is unfit for purpose of climate data reporting. The Met office claim of “collecting long records of accurate observations and for providing a unique history of recent climate.” ….. from a walled garden intentionally designed to elevate temperatures and create an artificial micro climate is patently untrue. The Met Office fully understands the effects of walled gardens on elevating temperatures – draw your own inferences from that.

This video has extensive views of the screen.

A typical screen grab shows this.

This begs the questions – if I install a regulation Stevenson Screen with accurate calibrated instrumentation in my walled back garden would the Met Office accept my figures? Are Met Office records now just a competition between walled gardens vying for the hot spot of the day? Whatever happened to integrity of data……and plain honesty?

Contributor “Oldbrew” recently drew attention to the Royal Meteorological Society’s guidance for home private weather stations. https://www.rmets.org/sites/default/files/2019-02/aws-guide.pdf It states

“Ideally, the screen should be fixed in an open place with good airflow on a level surface above short grass at the standard height. It should be no nearer than 30 metres (100 feet) from extensive concrete, aggregate or a road surface. Measure the height of surrounding objects above screen level: the distance from the screen to these objects should be at least two times these heights.
These are the ideals but what of the amateur siting his equipment in a suburban garden? There may be trees in the garden and if it is possible to move the screen far enough away from them it approaches too closely to the walls of the house, garden fence or hedging, or even off the lawn and into the herbaceous border………”

Clearly the Met Office has long ceased to be a credible data collecting organisation not even meeting standards advised for amateurs and Llysdinam proves the point.

Source: https://tallbloke.wordpress.com/2024/11/05/llysdinam-dcnn-8304-a-century-of-dubious-data/