Preston:Moor Park DCNN 7245 – A lack of Academic Oversight.

53.77426 -2.70480 Met Office Assessed Class 5 and Satisfactory Installed 1/1/1876

Preston:Moor Park is an automatic reporting weather station adjacent to the Jeremiah Horrocks Observatory, part of the Institute bearing the name of the famous 17th Century astronomer. It is now a section of the University of Central Lancashire (UCLan) which has several sites and associated colleges also housing weather stations notably Myerscough. Given its long history and close academic association, this weather station should be an example of a good quality site – but it is not. Again I am indebted to Phil Marshall for detailed site photography enabling an accurate site evaluation.

Despite being assessed as a the lowest possible standard of CIMO Class 5 (with inaccuracy due to siting of up to 5°C ) this does not stop the Met Office regularly proclaiming regional and/or national daily temperature “Extremes” from Preston:Moor Park with no mention of the known error margin.

{N.B. Almost all the national and regional daily highs that the Met Office announce throughout the year are from Class 4 and 5 weather stations, a small number of sites dominate the figures and it is an exception for a Class 1 site to be included. A future post will develop this theme with data kindly supplied by reader Eric Hux}

Apart from the obvious proximity to an Observatory Dome casting shadow over the screen (as recently highlighted as an issue with Oxford) what are the other problems? Phil’s images are most enlightening.

Firstly, how much closer could the screen have actually got to the brick built observatory? It scales out at just 12 metres. The synthetic courts are under 10 metres away with a bush in between. If the dome does not cast shade from one angle, the numerous surrounding trees do from several others. Going in for a closer look details the surface material.

Screens are supposed to be over grass or natural vegetation….well this one is, but only just! The extensive gravel area rules out any definition of natural vegetation. The heat absorption profile of gravel is completely unnatural for this area and will inevitably affect the screen temperature readings. So what does the Met Office say?

” To ensure consistency of measurements in the records, weather stations must meet strict criteria, in alignment with meteorological organisations across the world. This includes specific standards on the levels of grass-cover within the observations area, as well as having enough clear space for the weather station to be free from the influence of non-meteorological factors on the readings.” {My bold} Followed by:

Ideal site

Level ground.
No trees; buildings, or steep ground nearby that might influence the measurements.

Undesirable site

Warming effect of buildings on the measurement of temperature
Sheltering or shading effects of trees on the measurement of sunshine and wind.

https://www.metoffice.gov.uk/weather/learn-about/how-forecasts-are-made/observations/weather-stations

It is blatantly obvious, from their own definition, that this is an “undesirable site”. Quite how the Met Office can call this site “Satisfactory” is again a further indication of effectively non existent standards as demonstrated at Seavington:Hurcott Farm.

However, what makes this Preston:Moor Park site such a disappointment is that it simply does not have to be that way. Phil’s image looking south over the screen is very revealing.

The surrounding area is perfectly flat and there is no shortage of space. A minor relocation away from buildings and shade with a more natural surface turns this Class 5 site into a good quality one. Though it is unlikely to achieve 100m Class 1 separation it may well be possible to achieve a respectable Class 2, it would certainly be better than the absurd Class 3 rating given to the Heathrow site.

Preston could join that growing elite group of weather stations located by cricket pitches such as Coventry:Coundon and Linkenholt:Post Office and the even more illustrious Dunbar to be reviewed soon.

Jeremiah Horrocks used accurate observations to predict the 1659 solar transit of Venus and measure the obliquity of the Lunar orbit. It feels wrong that the successors bearing his name cannot manage accurate observations of much more mundane items.