Thorney Island WMO038371/2 – Gosport:Fleetlands alter ego?

50.81488 -0.92247 Met Office CIMO Assessed Class 3 Installed 1/1/1941

Thorney Island weather station lies in West Sussex close to the Langstone Harbour area next to Hayling Island. Former RAF Thorney Island is still an operational site (though now for the Royal Artillery) that was originally constructed in 1938 and featured prominently in the Battle of Britain. When Tim Channon originally reviewed this site he felt Class 1 was appropriate so the subsequent Met Office assessment of only Class 3 initially seemed odd. Whether things have changed since his review or was there something not evident was worth further investigation.

The first noticeable point was that the site had two different World Meteorological Organisation (WMO) recorded numbers plus two District County Network Numbers (5400 and 5401) . This suggested a site relocation at some time that was confirmed in the “Remarks” section of the archives as:

2000-10-09

Current

SITE INFORMATION

OLD SITE WAS AT GRID REF 4761E 1023N ELEVATION 4M

The given coordinates are not precise enough to locate the site exactly and there are confusing notes regarding the date of the move. The most likely conclusion was that it occured at some time around 1988/9

1995-11-23

Current

IDENTIFIERS

DCNN 5401 1941-1989; SAWS (5400/321374) from 1984; Gauge 321373 (‘B’) from 1988

The original manuscript copies from 1941 (not converted to the digital archives) also show a different location though again not precise enough to verify with pin point accuracy.

Again it is worth noting that the above site back then recorded to the nearest 0.1°F but the archived digital sets covering the 4 years of 1957 to 1960 indicate the crude conversion botching I noted here.

All of this is somewhat frustrating, a consistent site record from 1941 to date at a good quality site would be useful but with such uncertain historic provenance becomes too unreliable to consider.

So why the discrepancy between Tim’s assessment and the official one? The recent close up aerial imagery perhaps explains this.

There now appears to be some form of construction to the immediate north west that is tall enough to cast significant shadow. Additional fencing has been installed in the general surrounding areas and there is now a double fencing system around the enclosure. This is a very flat site and ground level breezes will be readily calmed before the Stevenson Screen. This is not a nitpick at all – the issue of over recording temperatures in Stevenson Screens (especially night time minima) is well recognised with recent research by Reading University suggesting up to 1 in 8 night time readings, Europe wide, could be adversely affected. Despite the “spin” that the very much pro AGW publication “The Conversation ” could put on the problem in its article, it still had to admit that “…...differences greater than 1°C. We estimated that across Europe about 4% of maximum temperatures will be affected in this way, and about 12% of recorded minimum temperatures.“

The above research was carried out at the Reading University Meteorological Department’s “White Knights” site, obviously a higher quality location. If such an effect is readily noted there then poorer sites will likely be far more prone to problems.  I suggest the Met Office current Class 3 assessment of Thorney Island falls into the same category as their Class 3 estimation of Heathrow i.e. somewhat suspect.

An additional aspect regarding siting standards are the comments that former senior Met Office manager John Maynard made in his excellent summary of Metrology. With all sites using PRTs to just one minute averaging such locations are liable to pick up any transient extraneous heat sources that the traditional LIGTs would not. Just 1 reading out of 1,440 sample points can cause major distortions to daily means.

Where does my cryptic reference to Gosport come into all this? Below is a recent UK Met Office “daily weather extreme” report indicating Gosport won the prize.

There is a hyperlink in the site name to further inspect the data from…..erm…..well one would expect Gosport….surely? Unfortunately, as I have noted on numerous occasions the link does not take you where you would expect. In the case of Usk No. 2 the Met Office referred to Chivenor a mere 68.6 miles away in a different country.

Bear in mind that the CEDA Archives hold no temperature data whatsoever for Gosport:Fleetlands and clearly state “No MIDAS Open data are available from this station” – probably having a weather station directly under the take off/landing route of Chinook helicopters gives them concern that the figures produced are not worth retaining. This is where that hyperlink takes you.

The Met Office does NOT provide any access to actually check Gosport’s previous immediate history and even in the case of Thorney Island all that is available are hourly readings that peak at 2.3°C lower than the claimed Gosport peak. One does wonder if there was any Chinook activity at Gosport that day!

The Met Office WOW site supplying the above Thorney Island above does not even recognise the existence of Gosport.

Why should the general public trust the doom laden proclamations of the Met Office such as their “State of the Climate Report” when the Met Office will not even offer credible verification of a single day’s temperature reading? The Met Office has become an untrustworthy organisation that has lost scientific credibility. This situation must change.

Source: https://tallbloke.wordpress.com/2025/09/30/thorney-island-wmo038371-2-gosportfleetlands-alter-ego/