Last week on 1 July the UK saw its warmest July daily max temperature on record (records date back as far as 1853), with 36.7 °C at Heathrow. This has led to considerable interest in the wider context of the record temperatures. Here, Mark McCarthy, Manager of the Met Office National Climate Information Centre discusses records and how we record them.
Where were record temperatures observed on 1 July 2015?
Although Heathrow measured the highest temperature recorded by the Met Office observing network on a July day, record temperatures were reported across a wide stretch of the country, including from some of the Met Office’s very long running climate stations.
Temperatures exceeded 35 °C at a handful of locations in London and the south east, but also reached the low 30s across the Midlands, East Anglia and parts of north-west and north-east England. It is in these areas that July temperature records were broken.
Map showing stations recording new July temperature records, 1 July 2015
The table below lists those stations with more than 50 years of observations for which 1 July 2015 was a record. These data show that record temperatures for July were not confined to London or other major urban centres. The records were, in fact, part of a larger scale pattern of high temperatures extending through Spain, Portugal and France.
| SITE | DATE OF PREV JULY RECORD | PREV RECORD JULY MAX (°C) | 1 JULY 2015 MAX (°C) | YEARS OF DATA |
| Durham | 31/7/1943, 10/7/1921 | 30.6 | 31 | 133 |
| Sheffield | 31/7/1943, 10/7/1921 | 31.7 | 33.3 | 130 |
| Bradford | 31/7/1943, 13/7/1935 | 30.6 | 30.9 | 106 |
| Cranwell | 22/7/1996 | 32.6 | 34.3 | 93 |
| Sutton Bonnington | 19/7/2006 | 32.9 | 33.6 | 84 |
| Stonyhurst | 3/7/1976 | 31.1 | 32.6 | 75 |
| Manston | 15/7/1983 | 31.4 | 33.6 | 74 |
| Goudhurst | 3/7/1976 | 32.8 | 33.3 | 74 |
| Waddington | 12/7/1949 | 32.2 | 33.1 | 67 |
| Heathrow | 19/7/2006 | 35.5 | 36.7 | 66 |
| Nottingham (Watnall) | 3/7/1976 | 32.3 | 33.9 | 64 |
| Marham | 3/7/1976, 5/7/1959 | 32.8 | 33.5 | 58 |
| Wittering | 5/7/1959 | 32.8 | 35.3 | 53 |
| St James’s Park | 5/7/1959 | 34.4 | 34.7 | 52 |
How does this compare to past heatwaves?
Temperatures over 36 °C reported at any station in the UK observing network are very rare, with only a handful of notable heatwaves seeing such extremes. The heatwaves of August 1990, August 2003, and July 2006 each saw a number of stations exceed 36 °C, whereas on 1 July 2015 Heathrow was the only station.
The Met Office maintains a list of climate extremes for the UK. It is standard practice to report the highest and lowest temperature every month as part of our routine monitoring of UK weather and climate. It is therefore always noteworthy when one of these records is broken.
While there is no doubt that some previous heatwaves have seen more extreme or more widespread high temperatures overall – particularly in the climatologically warmer period from late July into early August – 1 July 2015 has the honour of holding the highest recorded temperature for a July day with 36.7 °C at Heathrow.
How do you ensure the data are reliable?
To ensure consistency, Met Office weather records are only given for stations with standard instruments and exposure. This means that our records would not represent the extremes that may have occurred in places where we do not have standard instruments. This may have been the case on 1 July 2015, where the availability of additional data from amateur observers contributing to Met Office WOW show peak temperatures in the range 35 to 37 °C to the west London.
It is reasonable to ask whether Heathrow, as a major international airport, can provide a reliable climatological record. Are the observations biased by the presence of runways and air traffic?
The instrumentation and station enclosure are managed so that they meet the standards required by the Met Office 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.
The first thing we can do is compare the climatological temperatures with a nearby station at Kew Gardens. The average daytime maximum temperatures for the two sites are very close:
| Site | June | July | August |
| Heathrow | 21.04 °C | 23.54 °C | 23.15 °C |
| Kew | 21.02 °C | 23.48 °C | 23.15 °C |
On 1 July the maximum temperature recorded at Heathrow (36.7 °C) was higher than Kew (35.7 °C). Modern instrumentation means we can look at the temperatures minute-by-minute at the two sites, as shown below. The two locations recorded very similar temperatures through most of the afternoon and the average temperature at the two sites between 12:00 and 18:00 GMT agree to within 0.02 °C. However, there was a peak in temperature at Heathrow between 14:00 and 14:30 GMT that was not seen at Kew Gardens. What could cause such a peak?
Temperature (°C) graph for Heathrow and Kew Gardens 1 July 2015
There were scattered clouds in the area that afternoon. Both Heathrow and Kew Gardens have instruments measuring solar radiation, shown in the graph below. Both sites recorded a general dip in solar radiation due to clouds from approximately 13:30 to 15:00 GMT which corresponds to a slight cooling at both sites. Heathrow saw a short gap in the clouds shortly after 14:00 GMT 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 15:00 GMT and became warmer than Heathrow for about an hour.
Solar radiation (W/m2) graph for Heathrow and Kew Gardens 1 July 2015
Official blog of the Met Office news team 
The Met Office lost all credibility long ago when Slingo and the crew jumped on the AGW activist bandwagon. To claim that there is no UHI effect at a location a few metres from an airport runway just demonstrates how gullible they think the public are.
Just wait, there will be a few more of these ‘records’ reported by the Met Office before the Paris shindig to soften the public up. I’m sure if they attend a few bonfires around November and set up their instruments just downwind of the flames they can record a clutch of November records.
Still waiting for Peter Stott to provide the data proving a link between last January flooding in Somerset to AGW as claimed in several news interviews. Data proving hard to find Peter?
You said it. I’m sure there are some very nice people at the Met Office, but there have been far too many instances of pushing propaganda instead of facts.
It’s going to take a long time of total impartiality from the Met Office before I can trust it again.
How odd that “systems problems” are preventing the Met Office from releasing data on the Heathrow station on the particular day a record was supposed to have been set. One would think that the Met Office has something to hide.
It’s also odd that the other four weather stations in the immediate vicinity of Heathrow are all remarkably consistent in showing temperature around 3 degrees F lower than the Met Office ‘record’ temperature.
“It’s also odd that the other four weather stations in the immediate vicinity of Heathrow are all remarkably consistent in showing temperature around 3 degrees F lower than the Met Office ‘record’ temperature.” What specific stations are you talking about? At 35.7 C, Kew was only 2 F lower than Heathrow not 3 F (because of cloud in the early afternoon seemingly). And I suspect that Northolt was NOT significantly less hot than Kew last Wednesday.
“the climatologically warmer period from late July into early August”
Do you mean the ‘seasonally warmer’ period, or are you trying to make a point about AGW?
Reblogged this on the WeatherAction News Blog.
So what UHI allowance for Heathrow is used?
Using your own definition (http://www.metoffice.gov.uk/learning/learn-about-the-weather/weather-phenomena/heatwave) there was no heatwave last week (at Heathrow) because only two of the days (30th & 1st) had maxima that were 5°C above the long-term average of 23.5°C when a minimum of five such days are required. I have written my findings here:
http://wp.me/p3yVic-1fc
The definition of heatwave that I cut and pasted into my blog on the matter I took directly from you web site, but it has strangely disappeared when I look today.
This article raises more questions than it answers, e.g.
1) How can you compare a record temp at Heathrow with the previous record at Wisley Gardens? How much does the tarmac and jets at Heathrow add to temp?
To say that it fits WMO rules simply emphasises that no airports should be counted in global temp datasets. They were never set up for that purpose.
2) Max CET on 3rd July 1976 was considerably higher than last week, showing that although some parts may have been hotter last week, most was not. (This also shows the nonsense of trying to pretend early Aug is hotter than early July, a fact that is easily disproved by a look at the CET chart)
3) We also know that 3rd Aug 1990 was much hotter and affected most of the UK, unlike last week.
When are we going to see a proper comparison with 1976 and 1990, incl maps, so that we can put 2015 into proper perspective?
4) You list new July records, but don’t show how many stations did not break records. Nor how many disappear when you include August.
5) You show a spike at Heathrow, but don’t explain why this is not seen at Ruislip, just seven miles away, which was reporting at about 10 minute intervals around the same time.
While clouds may have been the cause, you 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.
Certainly no engineer would trust such a spike in any other field, and would throw it out unless he had frim evidence it was correct.
6) There is evidence that the automatic sensors we have nowadays pick up every little short term spike, which earlier thermometers could not.
Are we therefore comparing apples and pears.
For more questions and analysis, see here.
Paul
Thank you for your interest in last weeks temperatures. We have addressed many of your points in our blogs and news articles and will, as we do for spells of noteworthy weather, be publishing an event summary shortly that will put last week into context with previous hot spells. You’ll be able to find it on the climate pages of our website.
In consideration of a couple of your points above which have not been covered already, the records discussed are for the calendar month of July (not August); the CET is an areal measurement for a region stretching from London-Bristol-Liverpool whereas the records discussed are individual station values.
We’d like to point out that we publish blogs and articles without bias when any type of record is broken whether it be wet, dry, sunny, hot or cold.
I hope you’ll find all the information you need in the climate pages and previous information we’ve already published on this issue.
Helen
“without bias”
Don’t make me laugh.
Paul
On 1 July the wind was blowing generally from a southeast direction which means that aircraft were landing from the west and taking off from the east. We have checked with NATS and confirmed that the north runway, which is closest in proximity to our observing station, was being used for landing aircraft. Therefore landing aircraft would most likely have had idle engines by the time they reached the eastern half of the runway, where our observation station is sited.
This only confirms once again that it is extremely unlikely that aircraft movements influenced the temperature reading at Heathrow on 1 July. In addition the turbulence generated by passing aircraft would help mix the air close to the ground and so, is more likely to lower the air temperature rather than raise it.
However, we once again would point to the nearby data from our observing site at Kew Gardens to show that there is no evidence of a temperature bias either way at Heathrow: looking at all the daily maximum temperatures over the last 10 years from Heathrow and Kew Gardens the average difference between the two sites of 0.03 °C.
I hope this answers your questions about the impact of aircraft on the record July temperature recorded at Heathrow.
Helen
Early August max temp’s just peak above early July:
Would air heated by 100-200 MWh of combusted fuel and discharged in the vicinity of the runways, affect the air temperature measured by the equipment?
Especially if gusts of wind blew some of it towards the thermometer?
On 1 July the wind was blowing generally from a southeast direction which means that aircraft were landing from the west and taking off from the east. We have checked with NATS and confirmed that the north runway, which is closest in proximity to our observing station, was being used for landing aircraft. Therefore landing aircraft would most likely have had idle engines by the time they reached the eastern half of the runway, where our observation station is sited.
This only confirms once again that it is extremely unlikely that aircraft movements influenced the temperature reading at Heathrow on 1 July. In addition the turbulence generated by passing aircraft would help mix the air close to the ground and so, is more likely to lower the air temperature rather than raise it.
However, we once again would point to the nearby data from our observing site at Kew Gardens to show that there is no evidence of a temperature bias either way at Heathrow: looking at all the daily maximum temperatures over the last 10 years from Heathrow and Kew Gardens the average difference between the two sites of 0.03 °C.
I hope this answers your questions about the impact of aircraft on the record July temperature recorded at Heathrow.
Helen
“This only confirms once again that it is extremely unlikely that aircraft movements influenced the temperature reading at Heathrow on 1 July. In addition the turbulence generated by passing aircraft would help mix the air close to the ground and so, is more likely to lower the air temperature rather than raise it.”
Would someone please explain the physics of that statement?
The engines are discharging heat, i.e. adding heated air to the ambient air close to the ground. This increases the temperature of resultant mixed volume.
Any air at velocity though, won’t induce a cooling effect to the screened temperature measuring device.
In reference to the question surrounding turbulent mixing and how this can affect temperature:
On a warm, sunny day the ground gets heated from the sun, in turn the ground then heats the air above it. This means that the air nearest the ground becomes much hotter than that above and can lead to what is called a superadiabatic layer at the surface. This is where the temperature decreases at a rate greater than 10C/Km. This effect is most notable on dry, calm days when winds are light. If the wind is strong or gusty, then the air nearest the ground will be constantly replaced or ‘mixed’ and the heat will be distributed more widely. Therefore, in this case any turbulence generated by passing aircraft would have ‘mixed’ the air disrupting any superadiabatic layer at the surface.
Should the Met Office be the foghorn of climate alarmism? What is your remit, to provide accurate timely weather forecasting? Has your performance at weather forecasting improved over the years as your costs to the taxpayer have risen?
How differently would you perform if this office was on payment by performance for accuracy of weather forecasting?
You say they ‘know’ how the climate will change over the century but fail completely to accurately forecast weather events for the coming few weeks.
It it just me that sees the banality of this, or do taxpayers just shrug their collective shoulders and carry on paying?
Your inability to answer Paul Homewood’s questions and putting his comment in moderation just shows your lack of public responsiveness at this Met Office.
Tom, thank you for your comments. Our accuracy figures are updated every month on our website.
Regarding moderating comments, I would ask everyone to read our moderation guidelines https://blog.metoffice.gov.uk/moderation-guidelines/, and note that we “monitor the site mainly during normal working hours (0900 – 1730, GMT) and aim to process comments as quickly as possible.”
Thank-you for you reply but your reply beg yet more information please….
You say , “Our accuracy figures are updated every month on our website.”
So who independently verifies these figures? Are there any targets for improvement? If so, who sets them and how low are they set?
Also
Is this Met Office able to concisely answer Paul Homewood’s questions now that his comment is out of moderation.
“accurately forecast weather events for the coming few weeks”
I’ve been painting the outside of my house for the last two weeks and can assure you the Met Office has been unable to accurately forecast the weather for the following day on 80% of the days.
The Met Office has surely exposed itself as a prime target for some of George Osborne’s long overdue cuts. There are plenty other private firms which provide at least as good, if not more accurate, weather data as the AGW obsessed Met Office.
One further point.
On the map of “new records”, how many of these stations were operating back in 1976?
Records at stations with only a few years of data are meaningless.
If the Met Office were a private company, its inability to provide a service that its customers would be willing to purchase means that it would have gone bust years ago. It’s long past time for the Met Office senior personnel to be relieved of their duties and for some people with integrity and scientific/engineering ability to be put in charge of a slimmed down and fit-for-purpose organisation.
Starting with Julia Slingo first. She has done more damage to the Met Office than any of her predecessors ever managed. Activist propagandists should never be allowed to run an organisation that relies for its credibility on unbiased output.
I think a few people are being a bit hard on the Met. Office here. Yes, they may have sometimes been guilty of pushing the AGW political agenda, but this article is about actual observed temperatures and an all time record at one particular station. This is something that actually happened. There is no politics involved. I thought it was a good article. July first was an all time high for my own amateur station in Leicester (32.5C) as well, so I don’t doubt the figures are correct as reported. And there have nearly always been aircraft at Heathrow. What other issue is there?
You appear to rather gullible if you consider this article free of political propaganda, or doubt the validity of a reading immediately adjacent to the busiest airport runway in the UK.
More than a bit hard I think. The hearts of the Met Office staff must sink when they read the bulk of these comments.
It’s clear from the presented evidence that the 1st July was a very hot day and the hottest July day ever recorded at a large number of sites, 14 of which have over 50 years of observation each. It beggars belief that people could argue with this, do they think all those stations are wrong?
It seems that some people are so blinkered by their belief that climate change is not happening/not due to us that they immediately leap on any occurrence that they perceive might challenge that view and try to rubbish it. So much do they want to not hear such facts that they propose in all seriousness to dismantle a world class organisation merely so they can remain happily ignorant.
Carry on Met Office, you are doing a great job.
I don’t know anyone who does not agree that climate change has been happening for the last 4.5 billion years, and that man mas played some minor role in that, either through land use changes or the addition of a small amount of CO2 to the atmosphere.
There is a very big difference however between claiming that we will see 4- 6 deg C warming by 2100, as a new paper from the Met Office published this week claimed, and the expected 1.2 deg C warming expected from the doubling of CO2 according to the latest reputable papers. It is clear that climate sensitivity is MUCH lower than the alarmists at the Met Office have been claiming, and their reputations can only suffer even more by the promotion of temperature ‘records’ at stations adjacent to airport runways. No one was suggesting it was not a warm day, but does it not strike you as odd that the record was broken at a location where jet engined aircraft were taking off and landing. That weather station does not even remotely satisfy the quality standards laid down for weather stations contributing to the CET records.
If the MO “is doing a great job”, one would have thought it’d have no difficulty answering my logical question from 7th July; and, Paul Homewood’s supplementary question from 8th July.
If anyone from the MO reads this, would they at least provide an acknowledgement. Please.
Gilbert Smith. You have said,
“It seems that some people are so blinkered by their belief that climate change is not happening/not due to us that they immediately leap on any occurrence that they perceive might challenge that view and try to rubbish it. So much do they want to not hear such facts that they propose in all seriousness to dismantle a world class organisation merely so they can remain happily ignorant.”
“Blinkered,”
“do not want to hear such facts,”
“happily ignorant.”
Really?
Firstly, the climate is always changing.
Secondly, the pseudo science of “radiative heat trapping” by “greenhouse gases” at the heart of anthropological climate changed is physical nonsense.
The notion of “back radiation” enhancing the lower tropospheric kinetic distribution (temperature) can be shown by globally averaged data to be untrue. The upper troposphere by unit mass is in exact energy equilibrium with the surface potential temperature once values of specific humidity are accounted for and respective latent heat subtracted. Virtually all of the proposed “radiative greenhouse enhancement” has to occur within the lower troposphere due to the concentration of atmospheric water at lower altitudes. Water is present at about 5% of surface levels by 7.5km. Also pressure broadening of absorption lines has to be far more pronounced at near surface pressures 1013mb than at reduced upper atmospheric levels, the pressure at around 7.5km globally being around 400mb. But alas, there is no sign of it in the data.
In reality, the only temperature that we can attempt to calculate with a purely radiative model is Earth’s effective mean radiative temperature EMRT. This temperature reflects the physical necessity that at equilibrium the Earth will radiate to space in the long wave the equivalent of the short wave solar energy thermalised. As the Earth can be seen to radiate to space from satellite-borne instrumentation, we can determine the intensity of radiations from the respective radiating bodies (atmosphere, cloud, sea, land etc). We can then weight the respective mean temperatures of the radiating bodies by their independently measured emissivities to produce a single, weighted mean emissivity for the Earth radiating at the EMRT.
And this is where it goes belly up for the warmists. Enhancement of equilibrium temperature is achieved by a reduction in the mean emissivity which forces the increase of temperature. However, detailed analysis shows that the bulk of radiations ALREADY come from the atmosphere (not the surface) which is intrinsically low emissivity. But by adding more radiatively active gases the atmosphere’s emissivity is RAISED thereby allowing equilibrium at a lower temperature. The atmosphere’s ‘blue sky’ emissivity is around 0.65, cf land and sea at around 0.95 and cloud at around 0.54 weighted by proportional abundance. This gives an overall global emissivity of around 0.63 to 0.64 for the ‘Blue Planet’, with an effective mean radiative height somewhere between the surface and the planetary boundary layer within 1km of the surface with an EMRT of around 285K. These numbers are inferred from energy budget diagrams and independent emissivity measurements.
One further thing. Pure radiative models can only be reference across the insulation of a vacuum. Within the atmosphere radiative balance by itself is nonsense as all heat transfer processes are coupled and long wave radiation in terms of thermalised absorption and re-radiation is part of local thermodynamic equilibrium. By itself this radiative transfer cannot produce an inhomogeneity. It always strives to reduce any temperature gradient. The autonomous production of density, pressure and thermal gradients within any gravitationally bound gaseous envelope sets and maintains basic conditions. Once a thermal gradient (dT/dh =-g/Cp) exists then inter-atmospheric and surface to atmospheric radiative exchange will answer to this unless the gradient evolves. The persistence over time of the gravitationally set lapse indicates that the whole of proposed “greenhouse gas”, “upper atmospheric cooling” and “lower tropospheric heating” (heat trapping rubbish) has NOT caused any long term deviation from the classically derived lapse rate.
I think overall that I would prefer to remain ‘ignorant’ than to achieve your level of understanding sir.
Best regards.
Heatwaves are relatively rare in the UK, and their hottest locations vary from one to the next. If all heatwaves had roughly the same peak temperature there would always be quite a few locations for which the latest temperature was the maximum over a mere 50 years.
There seems to me to be an undue effort to portray a picture of rising temperatures when in fact there may be no such thing taking place.
The Daily Telegraph has now picked-up the story. I wonder if they (unlike me) will extract a formal response from you?
http://www.telegraph.co.uk/comment/11733731/Met-Office-caught-out-over-its-hottest-July-day-ever-claim.html
Christopher Booker eh? So it MUST be true!
Well the Met Office is yet to deny it’s true …..
Gilbert,
Your from the heart defence of the MET office is to be applauded, however, I fear that it is you who “blinkered by your own beliefs and that you no doubt jump on any occurrence which might help to support your opinions.
It is my personal opinion that no temp recordings should be taken from poorly positioned stations e.g airports, roads etc.. as they never seem to correspond with any of the nearby stations.
It should also be made extremely clear when the specific stations records began, has the station moved location, what possible external factors might cause some anomalies and most important if the peak temp is shown as a spike than it must be removed from the figures.
There was an intense heat wave over much of Europe during July and August 1949. It was speculated in the Press of the time and in various publications since, that the temperature around London reached over 100F.
This does not seem to be in the official records and I wondered where the reading was taken and what stopped it being authenticated? Thanks for your reply
Tony Brown
Tony
We have checked the Met Office observations for summer 1949 and there are no temperatures recorded near 100F (37.8C) in London. The highest temperature in the London area is 32.2C at Camden Square on 12th July 1949.
You can see the Monthly Weather Reports on our website . The highest temperature these quote is 92F (33.3C) at Worcester on 12th July.
Temperatures reached the 30s as far west as Newquay, as far north-west as Cheshire and as far north as Durham, but there are no values approaching 35C let alone 37C.
If the speculation you mention was around a reading from a non offical site then, unfortunately, we don’t have access to it and so are unable to comment.
Helen
Helen
So a very widespread heatwave if not the hottest?
Coming from South Devon myself I am sure those in the nearby Met Office in Exeter noticed that, whilst our weather has been rather pleasant, it has been by no means hot, so all the Daily Express type headlines passed us by!
Tony Brown
There is a bigger picture behind this story that most people seem to be missing, it concerns the introduction of electronic sensors to replace mercury thermometers that has occurred over the last 30 years across the world, as manual observing sites have been closed and replaced by automatic weather stations.
These temperature sensors are more sensitive and are being polled more frequently by data loggers. Who knows especially at airports (which make up at least 50% of the global observing network) a blast of warm air from a passing taxiing jet which may only last a few seconds or so, might be sensed by the sensor and not by the old fashioned mercury in glass thermometer.
I’ve expanded a little more on this in “Is global warming due to more sensitive thermometers?”
http://wp.me/p3yVic-1fV
I see that Benton has failed to answer my question about his previous comment.
He or she should also consider whether RHS Wisley (the ‘hot spot’ in July 2006) is particularly known for its tarmac and aircraft engines.
THIRD REQUEST:
Please will someone from the Met Office either acknowledge or categorically deny, that heat released during aircraft taking-off, landing (reverse-thrust) and taxiing at the world’s 3rd busiest airport may affect the readings of the temperature-measuring equipment located relatively close to the runways.
On 1 July the wind was blowing generally from a southeast direction which means that aircraft were landing from the west and taking off from the east. We have checked with NATS and confirmed that the north runway, which is closest in proximity to our observing station, was being used for landing aircraft. Therefore landing aircraft would most likely have had idle engines by the time they reached the eastern half of the runway, where our observation station is sited.
This only confirms once again that it is extremely unlikely that aircraft movements influenced the temperature reading at Heathrow on 1 July. In addition the turbulence generated by passing aircraft would help mix the air close to the ground and so, is more likely to lower the air temperature rather than raise it.
However, we once again would point to the nearby data from our observing site at Kew Gardens to show that there is no evidence of a temperature bias either way at Heathrow: looking at all the daily maximum temperatures over the last 10 years from Heathrow and Kew Gardens the average difference between the two sites of 0.03 °C.
I hope this answers your questions about the impact of aircraft on the record July temperature recorded at Heathrow.
Helen
Thank you for your response, Helen.
“…. looking at all the daily maximum temperatures over the last 10 years from Heathrow and Kew Gardens the average difference between the two sites of 0.03 °C.”
Which site is shown to be the warmer – Heathrow or Kew Gardens?
Aircraft movements would not have ‘spiked’ around 3.15 pm I don’t think: http://www.metoffice.gov.uk/news/releases/archive/2015/hot-july
@ Ashley Haworth-roberts (19:10:40) :
“Aircraft movements would not have ‘spiked’ around 3.15 pm I don’t think”
The issue is not when aircraft movements spiked. It’s whether heat emissions from 700 or so aircraft movements that day prior to the measured temperature spike, had any effect upon the adjacent air temperature.
It also begs the question ‘How could the Met Office know there was no effect?’, since the air around that particular station has always been affected by aircraft heat emissions.
It seems the heat was more widespread (and built up more gradually and for a bit longer) leading up to 19 July 2006: http://news.bbc.co.uk/1/hi/england/5193970.stm
Of course jet engines don’t move much air, do they?
Today’s question to the Met Office is:
If a 747’s exhaust ‘Throw’ increases from 435m to 625m when the engine exhaust velocity decreases 30% from 22.352 m/sec (50mph) to 15.65 m/sec (35mph), how far away will its exhaust discharge be distributed when the exhaust velocity decreases by a further 96%, to 0.5m/sec?
http://tinypic.com/r/11j23af/8
It’s a shame the Met Office has come to this. It’s ceased to be a weather forecaster (not that it was any good at that, but at least it was contributing to the GDP by trying to help the productive part of our economy) and now is managed by zealots who want to influence political actions they approve of.
It’s not what they’re paid for, but then the BBC isn’t paid to push a left-wing agenda either. One thing for certain the public will eventually decide to get what they’re paying for from both organisation. The sooner the better.
The rapid rise in temperature at Heathrow looks too sharp to be explainable as just the sun coming out. One might expect a tarmac surface to react that fast but not grass nor a thermometer 2m above the ground inside a Stepehnsen Screen which is supposed to shield it from the sun.
I think a more likely scenario is that a China South Boeing 787 which landed from Guangzhou at 14:09 exited the runway next to the Met Station because it had to make its way to Terminal 4. With heavy traffic it may have been delayed on the Taxiway with engines running. The SE wind then exacrebated the heating effect. See: