Gravesend:Broadness WMO03784 – The Weather Station that never really should have been, a personal tale.

51.46461 0.31110 No Known Met Office CIMO Assessment Installed 15/9/1995 Closed 30/8/2018

The Gravesend:Broadness weather station was the subject of much debate during its short lifetime. Tim Channon reviewed the site here and there were a number of other discussions on the Talkshop and elsewhere relative to the site. Many others have queried the accuracy of this site whilst some have defended it though I suspect most have never been there nor actually seen it. For my part I would like to add my own observations on the basis that I have been inside the compound more than once when it was actually operational.

Gravesend (also known in Met Office circles as Broadness) is neither in Gravesend nor even in Gravesham local authority area. It comes under Swanscombe and should be more correctly described as Dartford. However, as Dartford is well known due to the Thames Crossing and suggests proximity to London, it was probably misnamed to “disguise” its real location.

Gravesend was a regular star performer in the daily extremes stakes as a national hot-spot and even claimed the national record all time high in 2003 before being beaten by a farcical reading at the Faversham manual reporting station. Faversham will be reviewed separately in future but it is worth noting now that the record readings there were not accepted by the Royal Meteorological Society chairman. The late Philip Eden personally inspected the site after the event and refused to rule out that “actions by persons unknown” had affected the reading.

Emeritus Professor of Psychology at the University of Dundee, Trevor Harley, is also a keen amateur meteorologist and has produced a list of hottest days of each year. This shows the regular appearances of Gravesend during its short lifetime. Note the 2014 record is quoted as Swanscombe Marsh which was actually the Gravesend site under another alias.

https://www.trevorharley.com/hottest-day-of-each-year-from-1900.html

To this day the Met Office still acknowledges that Gravesend holds the all-time national October high of 29.9°C on 1/10/2011.

This is what the site looks like now which is pretty much the same as it did BEFORE the Met Office had anything to do with the area. Note the complete absence of a Stevenson Screen in this and the headline image.

I have no wish to belittle theories regarding the nature of the sand/soil, the tide, the surrounding berm, Littlebrook D power station discharge, the UK’s tallest pylons (190 metres high and not shown in the image above) carrying the 400kV transmission line over the Thames, the metallic nature of the compound structure or any other such idea. My view is from my own very immediate experience.

The site was originally built for the Thames navigation radar and is locally known just as “Broadness Radar”. The Met Office (for whatever reasons – though I suggest possibly questionable ones) opted to site a screen in the high security compound many years subsequent to the radar station’s construction. This is what it subsequently looked like.

I initially visited the site in 2004 on behalf of a marine coatings company for whom I was consulting in relation to long term protective coatings maintenance elements of this and other marine/coastal sites. I was completely unaware of the weather station and had little interest in such things at the time. There were additional security issues then as some of the “travelling community” were camped around the area with almost feral dogs running free – this is a rather inhospitable site at the best of times. A colleague and I were escorted to the site by a security officer in a large pickup truck.

Inside the compound on a hot early summer’s day the first and most noticeable thing I encountered by the entrance gate in front of the screen was the waft of warm air from the equipment room’s air conditioning. It was similar to walking past a restaurant’s exterior cooling fan outlet that nearly always seems to smell of stale cooking oil though in this case it had the slightly “fishy” smell of overloaded electrical circuits.

We measured the temperature of the extensive steel work (a requirement for calculation of dew point and curing time for “two- pack” coatings) and noted the potentially adverse effects of premature ” film blocking” for multiple coating in the vicinity of the air con outlets warm air draughts. After surveying the site and about to leave, my colleague commented “what a dumb place to put a weather station” – I had not even noticed it but on stopping to consider it we both agreed it was bound to pick up on the air con output. I did not give it a second thought at the time.

A few weeks later the two of us revisited the site in a more “relaxed” mood as the “travellers” had moved on and there were no intimidating dogs snarling at us though the newly coated perimeter fencing. Checking the site works we again noted the strength of hot air blowing from the large air con units located on the east and south elevations of the equipment housing. With more “comfortable” time available we took a look at the screen and both agreed it was bound to be affected at times, particularly warmer days, when the air con was working harder and the breeze was blowing over it. It was none of our immediate concern any more though we did note possible premature coatings breakdown due to embrittlement in the immediate few metres around the air con outlets.

It was not until some years later that I discovered this was the same site that so regularly claimed the UK’s highest temperatures and the realisation that the readings were almost certainly (in my observed opinion) elevated due to the air con units.

As I mentioned above most who commented on this site somehow overlooked the obvious and opted for some quite esoteric explanations. Of particular interest was an official Met Office response by their press officer Nicola Maxey –

“When open the station satisfied the usual criteria for weather stations in terms of its exposure, and was regularly inspected by the Land Surface Observations team.

“The concrete and railings would only make a very small difference to the temperature readings, probably greatest on sunny days with light winds but even then only a couple of tenths of a degree.”

Presumably Nicola had not read the script of the WMO website which focused on:

“Every part per million and every fraction of a degree temperature increase has a real impact on our lives and our planet. Prof. Celeste Saulo, WMO Secretary-General”

A “couple of tenths of a degree” is a fifth in fraction terms. It pails into insignificance compared to the warm air exhaust from the cooling units.

The Kentonline article is particularly revealing in many ways. The quoted local “expert”, Lester Gosbee states

“It’s {Editors note: presumably the weather station} overexposed to concrete and it has metal railings around it to stop it from being vandalised”

This is quite an absurd remark, the security was for the sole and original purpose of protecting nationally important and very expensive radar navigation equipment and nothing at all to do with the Stevenson screen. {Lester Gosbee will be included in the review of by far the worst weather station site in Kent (Frittenden) which he is responsible for – a relatively new Class 5 site and regular star performer in the national Met Office “Daily Extremes” listings.}

The Met Office given reasons for the site’s closure seem equally improbable. “It closed on August 30 last year after the weather service said there had been “significant changes to the site”, at Broadness, near Swanscombe, citing the development of the London Resort theme park as one of the reasons.”

The closure on these grounds seems remarkably ahead of time, the proposed theme park never happened and likely never will. It was also incredibly unlikely that the radar station site (complete with broadcast antenna and the large pylons carrying 400kV transmissions lines) were going anywhere in a short timescale. The site is still there and unchanged 6 years after the weather station closure.

My personal view is that the Met Office realised this site was producing artificially high temperatures that were way off scale and could no longer be passed off as reliable. The station was quietly closed down to avoid further potential embarrassment and “reasons” were supplied after the event.

This may be considered “water under the bridge” but my personal view is that any reasonable meteorologist responsible for installing this Screen or subsequently maintaining/inspecting it would unquestionably have been aware of the problems I have highlighted. That it was ever installed in the first place and then survived for so long indicates, to me, dubious motives.

Source: https://tallbloke.wordpress.com/2024/11/18/gravesendbroadness-wmo03784-the-weather-station-that-never-really-should-have-been-a-personal-tale/