Daily Telegraph & Heathrow Record Temperature Claims
By Paul Homewood
The row over the Met Office’s claim of record temperatures at Heathrow has been picked by the Daily Telegraph:
The Met Office has been forced to defend the way it monitors temperatures after critics claimed weather station readings were skewed by the heat from aircraft.
According to forecasters Britain experienced its hottest July day ever on the first of the month, when temperatures nudged 100F at Heathrow.
But the climate blogger Paul Homewood said he had checked four other weather stations nearby and none showed such extreme readings.
Even The Met Office admitted that readings at neighbouring Kew Gardens, which are usually very close to airport temperatures, were more than two degrees cooler at the time of the supposed record-breaking spike. While Heathrow recorded 98F (36.7C) Kew only reached 96F (35.7C)
But the weather service said that a sudden break in the cloud at the airport had allowed temperatures to temporarily soar, while overcast conditions had kept things cooler just a few miles away at the Royal Botanic Gardens.
Mark McCarthy, Manager of the Met Office National Climate Information Centre , said: “There were scattered clouds in the area that afternoon. Both Heathrow and Kew Gardens have instruments measuring solar radiation. Both sites recorded a general dip in solar radiation due to clouds from approximately 1.30pm to 3.30pm which corresponds to a slight cooling at both sites.
“Heathrow saw a short gap in the clouds shortly after 2pm which resulted in a similarly short lived peak in temperature, while Kew Gardens remained cloudy.
“In turn Kew Gardens then saw a brief spell being sunnier than Heathrow just before 3pm and became warmer than Heathrow for about an hour.”
Did aircraft at Heathrow skew temperature readings on July 1?
Mr Homewood said the actual figures show a strange 1.7 degree temperature spike at 2.15pm and suggested that extra heat could have been generated by the heat from a nearby runway which would have been experiencing a busy Wednesday afternoon. Thermometers surrounded by tarmac have been known to exaggerate heat conditions if the wind suddenly changes direction.
“While clouds may have been the cause (The Met Office) fail to rule out other non-climatic factors, such as a subtle windshift bringing hot air from the runway. This is a well-known phenomenon at airports,” said Mr Homewood.
“No engineer would trust such a spike in any other field and would throw it out unless he had firm evidence that it was correct.
“It is hard to avoid the conclusion that the reading at the Met Office station at Heathrow is either incorrect, or has been artificially inflated by local, non-climatic factors.”
However the Met Office insisted that the data was reliable and the weather station met international requirements for temperature monitoring.
“It is reasonable to ask whether Heathrow, as a major international airport, can provide a reliable climatological record,” added Mr McCarthy
“But the instrumentation and station enclosure are managed so that they meet the standards required by the MetOffice and set out by the World Meteorological Organization.
“The site has been operating for 66 years and provides an excellent long observational series for west London.”
In true Science Editor fashion, Sarah Knapton appears to have done no more than cut & paste parts of my blog and the Met Office’s response from last week. It is a pity she did not put some of the questions I raised to Mark McCarthy, as they still remain unanswered.
Still, some of the comments are hilarious and overwhelmingly anti Met Office.
Comments are closed.
NOT A LOT OF PEOPLE KNOW THAT 
Great to know someone from the mainstream media is picking up at what you have published at your blog! “Cut and paste” is progress. Much better than ignoring insightful, diligent bloggers.
Is this the first time that someone other than Christopher Booker at the Telegraph has picked up on one of your blog posts?
Is it in the “real” newspaper, as well as the on-line version?
Yup, in the print version, next to photos of Shed of the Year and an article about worms using slugs as taxis for long distant journeys! Real newspaper!
That’s good.
I used to buy the Telegraph every day but stopped because it was full of “celebrity” gossip.
Page 9 apparently!
For a break in the clouds to produce a large spike in temperature the sunlight must get absorbed by some nearby material with low heat capacity, such as tarmac or sand. Anyone who has walked on sun-warmed sand at a sunny beach knows how hot it can get, and many people will have seen “melted” tarmac. Such material near the thermometer must surely make the station unsuitable for measuring air temperature. Now I understand why the Australian BoM recommend that thermometers be mounted over grass.
Thermal conductivity must also play a big part, probably a major reason why surface sand gets so hot. I’m sceptical of this cloud break theory, wind changes bringing hotter air from somewhere else seems more plausible.
“Now I understand why the Australian BoM recommend that thermometers be mounted over grass.” Good God, doesn’t ours? The one I tended for part of an adolescent summer was over grass.
Aw, c’mon, let em record it as the ‘hottest spike evah!’.
Well done Paul and thank you so much for all your work on these issues.
Watch what comes out of Kew also. In June I was in England for Magna Carta 800th as a descendant of 2 of the barons and William Marshal. Since I am a botanist, I spent an afternoon at Kew Gardens. The Xstrata Treetop Walkway sounded neat, so I walked up and across. Don’t bother it is mostly horse chestnut and indoctrination. I wanted to hurl myself off when I read the following bronze stem w/ buds posted along the fence:” Buds are bursting weeks earlier because of global warming.” Show me the original;, un-tampered with, data for that one.