Heat Island At Heathrow
By Paul Homewood
I thought I would take a look at temperature trends at Heathrow Airport, since records began in 1948, and compare them with the nearby site at Oxford. The results are astonishing.
The trend in annual mean temperatures at Heathrow since 1948 has been 0.027C/year. Now contrast with Oxford, which is 47 miles to the west.
The trend at Oxford is 0.020c/year, about a quarter less. Put another way, Heathrow is warming at a rate of 0.7C per century more than Oxford.
The weather station at Oxford is in the garden of Green College, but is still not totally unaffected by UHI, as it lies in within the bounds of the city of Oxford.
Radcliffe Observatory, Oxford
Heathrow, of course, has grown out of all proportion since it began civil operations in 1946, as little more than a grass field with a few propeller planes carrying 63,000 passengers. Last year, more than 73 million flew from Heathrow.
Of course, it could be that there are genuine climatic reasons for the warmer trend at Heathrow, even though Oxford is only just up and the road, and both are inland sites. However, the probability that the heat island at Heathrow is responsible is much strengthened when we look at the Central England Temperature trends, which is based on the Midlands region bordering on Heathrow.
We actually find that the trend of the CET is less even than at Oxford, 0.014C/year. This would suggest that maybe half of the warming at Heathrow has been caused by the heat island.
Much of the temperature data used for global calculations these days come from airport sites, pretty much all of which have developed from small operations, usually just after the war. Though most don’t approach Heathrow in size, this analysis suggests that heat island at airports is a significant factor which may not being taken into account.
Regardless of the global implications, it clearly makes a nonsense of “the hottest UK July day” claim.