On Sunday, 12 July 2015 23:46:40 UTC+1, Len Wood wrote:
On Sunday, 12 July 2015 17:42:56 UTC+1, Bruce Messer wrote:
He seems to have been reading the comment that I made in this newsgroup on the 8th of July.

in the "Met Met Office explanation of Heathrow record" I did post "it would be interesting to see a graph of aircraft takeoff and landings for that day and just wonder if they were just clearing a bit of a delay on long distance 747's at around the time the maximum occurred"

Having worked at RAF stations for a good part of my observing career, it does seem plausible depending on the exact siting of the Stevenson screen..

Interestingly 6 (or maybe 7) of the 14 record breaking sites that the Met Office list in their blog are also on airfields!

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Here is a photo of the Stevenson screen at Heathrow airport with a Virgin 747 taxing in the background.

Scroll down to page 7 and Fig 4 in this UKMO doc:
http://cedadocs.badc.rl.ac.uk/270/1/factsheet17.pdf

Nuff said?

Len
Wembury

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Nuff said? Well no, not really. Are we to assume that the exhaust from an aircraft taxiing (basically on tickover) at about right angles to the line to the screen is going to affect the readings. It seems highly improbable to me.
Equally, with takeoff the blast is never directed at the screen and will contain large amounts of entrained air (the ejector effect) anyway.
The synoptic station at Gatwick was moved to Charlwood (I don't know all the reasons for this) and the site at Heathrow could be moved just as easily if the Met Office thought it appropriate but it seems satisfied. Should we stop being so sceptical of the place?

Tudor Hughes, Warlingham, Surrey.