St Athan WMO 03716 – Taxiway Temperature Taking – but not by the “Runway”.

51.40543 -3.44077 Met Office assessed CIMO Class 5 & Satisfactory Installed 1/9/1988

Another aviation site subject to similarly close proximity of aircraft movements as highlighted at DYCE . The wider area view clearly demonstrates that aircraft, under power and on the taxiway, must regularly pass very close to this site likely queueing at busy periods as shown.

Any reasonable person would conclude that the exhaust heat from aviation gas turbine engine exhausts in such close proximity would affect instruments taking temperature readings. So what is the view of the alleged experts in this field? From https://www.metoffice.gov.uk/weather/learn-about/how-forecasts-are-made/observations/weather-stations

“For example, official weather stations are often located at airports as they have plenty of open space making them a good place for observations to take place. However, the observation equipment is set an internationally-agreed distance from the runway to ensure no external factors can influence readings in any way.”

Notice how carefully worded that statement actually is – “internationally-agreed distance from the runway”

There is NO internationally agreed distance from a runway (hyphenated or not.) Nowhere in the CIMO assessment procedure refers to the specific terminology of “runways”, after all, that would exclude “taxiways”. If there really were an “internationally-agreed distance” why not simply state what that distance is?

And then “….ensure no external factors can influence readings in any way.” Gas Turbines seemingly do not count as “external factors”? Do meteorologists never stand downwind of powerful heat sources? Jet engine exhausts run up to 850°C.

What the CIMO assessment procedure does refer to is

2.2 Class 1
(a) Flat, horizontal land, surrounded by an open space, slope less than ⅓ (19°);
(b) Ground covered with natural and low vegetation ((c) Measurement point situated:
(i) At more than 100 m from heat sources or reflective surfaces (buildings, concrete
surfaces, car parks, etc.);
(ii) At more than 100 m from an expanse of water (unless significant of the region);
(iii) Away from all projected shade when the sun is higher than 5°.

The only distance mentioned is of “buildings, concrete surfaces, car parks, etc.” presumably on the assumed basis that no credible meteorological organisation would ever consider proximity to fully functioning jet engine aircraft as acceptable but the UK Met Office demonstrably does. Very obviously somewhat mealy-mouthed words from the Met Office.

For St Athan’s readings to be considered acceptable for the historic climate record is clearly indefensible, however, the Met Office regularly proclaims this site as a regional daily high and allows it to distort the overall climate record. Surely this is unacceptable.