Cambridge NIAB DCNN 3254 – A Class 1 site (sometimes) with yet another “creative” history.

52.24545 0.10032 Met Office CIMO assessed Class 1 Installed 1/1/1959 Temperature data archived from 1959

The National Institute for Agricultural Botany (NIAB) operatee this site at their principle Cambridge campus in Histon on the outskirts of Cambridge. It lies just 7 kilometres from the Cambridge Botanic Gardens site and has the rare distinction (for a rural site) of being specifically marked and named on google aerial images as above. This unusual site marking becomes all the more interesting when its history is considered.

The Met office currently assess this site as the best possible Class 1 though curiously this is only recent as in 2021 it was shown as Class 2.

This elevation may be one of the known Met office default setting issues with all stations rated as Class 1 unless manually altered as shown at both Hastings and Edenbridge. However, the site looks to be reasonably good and should meet acceptable standards with just one small caveat for which I am seeking clarification from the Met Office. Here is the site with a 100 metre circled area shown.

There do not appear to be any problematic extraneous heat sources nearby. Conventionally assessed Urban Heat Island warming effects shown to be so prevalent at the Botanic gardens site ( resulting in its removal from the CET back in 1931) do not appear to be obvious here. However, there is a potential problem to the north east perimeter of the 100 metre circle being the 132kV Histon electricity sub station. As highlighted in reviews of Amersham Field Centre and Bingley No 2 there is such a high level of waste heat from large electricity transformers that consideration has been given to using them to supply large district heating networks. I will notify any Met Office response regarding EL sub stations if they chose to respond.

If there is no interference from the Sub Station I feel this site would be otherwise acceptable for the long term temperature record and there comes the issue. How long has it actually been there?

Archived temperature records dating back to 1959 are available to view online. The station has just one unique District County Network Number (DCNN). When weather stations are moved over a predetermined distance (typically more than 400 metres) or the climatology of the new site is significantly different from the original location then it is given a new DCNN and usually a new name or suffix number i.e. “Bingley Number 2” as mentioned above. From the Met Office 20th century guidance notes:

“Over time certain instruments, or the whole enclosure, may be relocated some distance away from the original site. Where the distance moved is small, the observations obtained from the new site may have exactly the same climatological characteristics as previously and it makes sense to regard them as coming from the same source or station distinguished by certain identifiers. Where the distance moved is large, or, where the exposure at the new site is sufficiently different that a detectable impact on the measured climatology is judged likely, it is appropriate that observations from the new site are labelled by a different set of identifiers.”

Here is the current streetview image of the site as of August 2012.

However, if you scroll back in time to the previous image from the same spot, there is no weather station visible in the August 2008 image. This becomes exactly the same issue as highlighted at Southampton, Lowestoft and Braemar (and there are more to come) but, even worse in this case, the splicing together of data from distinctly different locations is totally covert.

The location co-ordinates given (52.245 0.102) are not changed at any time throughout the time series. It was only when I realised that the digital coordinates given are NOT the same location as the UK Grid Reference locators of 543500E and 260600N that I initially found this

And then using Google Earth Pro was able to go “back in time” to before the construction works to finally find this original location.

So how far was this old site from its new replacement? The small matter of 2.26 kilometres but also on a site owned by NIAB…..and with the A14(T) dual carriageway in between…and 16 metres difference in elevation found from Elevation Finder……and climatologically – significantly different.

When this relocation exactly took place required even further trawling through records to identify but eventually I was able to prove it was 19th June 2009. One indicator is here in changing the indicator from previoiusly DLY3208 to ongoing AWSDLY:-

And also the site archive indicates the 19th June change over all supported by the street view imagery.

What difference is this covert relocation likely to make? In the new location on that record hottest day in 2022 the site was in almost exact agreement with the known compromised nearby Botanic Gardens site at 39.9 °C. However, in its old site on previous record hot days it was anything but in agreement with its near neighbour. In the Faversham record breaking year of 2003 on the 10th August there was almost over a degree differential with the NIAB site cooler. Going back to the 1990 Chelmsford record breaking date of 3rd August the differential made NIAB 1.3 °C cooler than the Botanic Gardens. The original site indicates much cooler than both its replacement and manually reporting near neighbour.

In conclusion we have come back to the Met Office splicing together data from two different sites. It took someone like me, who is extremely well versed in this specific type of investigation, nearly two days to finally get to the hard provable data. Going back to my Southampton review, it is clear to see how incredibly easy it is for the Met Office to use their “appeal to authority” position to pass off spurious data as fact to prove an argument to the impressionable in society. I contend these sorts of practises are wholly against the public’s well being and are deceitful.

Source: https://tallbloke.wordpress.com/2024/12/18/cambridge-niab-dcnn-3254-a-class-1-site-sometimes-with-yet-another-creative-history/