In the report ‘hottest day ever’ must mean ‘since the weather station was installed’, but we’re used to this kind of excitable exaggeration in BBC climate reporting. At least they are admitting the obvious here, that Heathrow has certain heat-related factors built-in.
It’s Europe’s busiest airport, says BBC News, and as well as attracting millions of passengers could Heathrow also be a magnet for the sizzling heat?
Heathrow holds the UK record for July’s hottest day ever. Three years ago it reached a sweltering 36.7C.
It also briefly recorded 2018’s highest temperature of 35C, before being pipped by Faversham (35.3C) in Kent last Thursday.
And last year the thermometer peaked at 34.5C at – you guessed it – Heathrow.
So what’s causing Heathrow to rise to the top of the temperature charts?
How is temperature measured?
To get a standardised temperature, a weather station, known as a Stevenson Screen, is used.
These white boxes, which contain a thermometer, are installed 4ft (1.25m) above the ground and are dotted all around the UK.
The weather station at Heathrow is located very close to the northern runway, so with aeroplanes constantly landing and taking off, does it make a difference to the temperature?
Not according to Paul Williams, Professor of Atmospheric Science at the University of Reading.
“Planes make a negligible difference,” says Professor Williams.
“Every time you use energy – whether it’s from a plane’s engine, or even just switching on a light bulb or taking a shower – it’s eventually turned into heat.
“But all of that is a minor influence compared to the effect of the urban heat island.”
The urban heat island is, Prof Williams explains, the process where buildings absorb more sunlight than open fields.
Cities tend to hang on to the heat for longer, which can push up temperatures by a few degrees, he says.
Heathrow – with its large black asphalt runways and airport buildings – will naturally absorb more heat.
Continued here.
via Tallbloke’s Talkshop
August 2, 2018 at 02:54AM
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